import SwiftUI
import AppKit

// MARK: - MarkdownLayoutManager

class MarkdownLayoutManager: NSLayoutManager {
    struct BlockRange {
        let range: NSRange
        let kind: BlockKind
    }

    enum BlockKind {
        case codeBlock
        case blockquote
        case horizontalRule
        case checkbox(checked: Bool)
        case tableBlock(columns: Int)
    }

    var blockRanges: [BlockRange] = []

    override func drawBackground(forGlyphRange glyphsToShow: NSRange, at origin: NSPoint) {
        super.drawBackground(forGlyphRange: glyphsToShow, at: origin)

        guard let textContainer = textContainers.first else { return }

        for block in blockRanges {
            let glyphRange = self.glyphRange(forCharacterRange: block.range, actualCharacterRange: nil)
            guard NSIntersectionRange(glyphRange, glyphsToShow).length > 0 else { continue }

            switch block.kind {
            case .codeBlock:
                drawCodeBlockBackground(glyphRange: glyphRange, origin: origin, container: textContainer)
            case .blockquote:
                drawBlockquoteBorder(glyphRange: glyphRange, origin: origin, container: textContainer)
            case .horizontalRule:
                drawHorizontalRule(glyphRange: glyphRange, origin: origin, container: textContainer)
            case .checkbox, .tableBlock:
                break
            }
        }
    }

    override func drawGlyphs(forGlyphRange glyphsToShow: NSRange, at origin: NSPoint) {
        guard let textContainer = textContainers.first else {
            super.drawGlyphs(forGlyphRange: glyphsToShow, at: origin)
            return
        }

        var skipRanges: [NSRange] = []
        for block in blockRanges {
            guard case .checkbox(let checked) = block.kind else { continue }
            let glyphRange = self.glyphRange(forCharacterRange: block.range, actualCharacterRange: nil)
            guard NSIntersectionRange(glyphRange, glyphsToShow).length > 0 else { continue }
            skipRanges.append(glyphRange)
            drawCheckbox(checked: checked, glyphRange: glyphRange, origin: origin, container: textContainer)
        }

        if skipRanges.isEmpty {
            super.drawGlyphs(forGlyphRange: glyphsToShow, at: origin)
            return
        }

        skipRanges.sort { $0.location < $1.location }
        var cursor = glyphsToShow.location
        for skip in skipRanges {
            if cursor < skip.location {
                super.drawGlyphs(forGlyphRange: NSRange(location: cursor, length: skip.location - cursor), at: origin)
            }
            cursor = NSMaxRange(skip)
        }
        if cursor < NSMaxRange(glyphsToShow) {
            super.drawGlyphs(forGlyphRange: NSRange(location: cursor, length: NSMaxRange(glyphsToShow) - cursor), at: origin)
        }
    }

    private func drawCodeBlockBackground(glyphRange: NSRange, origin: NSPoint, container: NSTextContainer) {
        var rect = boundingRect(forGlyphRange: glyphRange, in: container)
        rect.origin.x = origin.x + 4
        rect.origin.y += origin.y - 4
        rect.size.width = container.containerSize.width - 8
        rect.size.height += 8

        let path = NSBezierPath(roundedRect: rect, xRadius: 6, yRadius: 6)
        Theme.current.surface0.setFill()
        path.fill()
        Theme.current.surface1.setStroke()
        path.lineWidth = 1
        path.stroke()
    }

    private func drawBlockquoteBorder(glyphRange: NSRange, origin: NSPoint, container: NSTextContainer) {
        var rect = boundingRect(forGlyphRange: glyphRange, in: container)
        rect.origin.x = origin.x
        rect.origin.y += origin.y
        rect.size.width = container.containerSize.width

        let bgRect = NSRect(x: rect.origin.x + 8, y: rect.origin.y, width: rect.size.width - 16, height: rect.size.height)
        Theme.current.surface0.withAlphaComponent(0.3).setFill()
        bgRect.fill()

        let barRect = NSRect(x: origin.x + 8, y: rect.origin.y, width: 3, height: rect.size.height)
        Theme.current.lavender.setFill()
        barRect.fill()
    }

    private func drawHorizontalRule(glyphRange: NSRange, origin: NSPoint, container: NSTextContainer) {
        let rect = boundingRect(forGlyphRange: glyphRange, in: container)
        let y = rect.origin.y + origin.y + rect.size.height / 2

        let path = NSBezierPath()
        path.move(to: NSPoint(x: origin.x + 8, y: y))
        path.line(to: NSPoint(x: origin.x + container.containerSize.width - 8, y: y))
        path.lineWidth = 1
        Theme.current.overlay0.setStroke()
        path.stroke()
    }

    private func drawCheckbox(checked: Bool, glyphRange: NSRange, origin: NSPoint, container: NSTextContainer) {
        let rect = boundingRect(forGlyphRange: glyphRange, in: container)
        let size: CGFloat = 14
        let x = rect.origin.x + origin.x
        let y = rect.origin.y + origin.y + (rect.size.height - size) / 2
        let boxRect = NSRect(x: x, y: y, width: size, height: size)
        let path = NSBezierPath(roundedRect: boxRect, xRadius: 3, yRadius: 3)

        if checked {
            Theme.current.green.setFill()
            path.fill()

            let check = NSBezierPath()
            check.move(to: NSPoint(x: x + 3, y: y + size / 2))
            check.line(to: NSPoint(x: x + size * 0.4, y: y + 3))
            check.line(to: NSPoint(x: x + size - 3, y: y + size - 3))
            check.lineWidth = 2
            check.lineCapStyle = .round
            check.lineJoinStyle = .round
            NSColor.white.setStroke()
            check.stroke()
        } else {
            Theme.current.overlay0.setStroke()
            path.lineWidth = 1.5
            path.stroke()
        }
    }

    private func drawTableBorders(glyphRange: NSRange, columns: Int, origin: NSPoint, container: NSTextContainer) {
        guard columns > 0 else { return }
        var rect = boundingRect(forGlyphRange: glyphRange, in: container)
        rect.origin.x = origin.x + 4
        rect.origin.y += origin.y
        rect.size.width = container.containerSize.width - 8

        let outerPath = NSBezierPath(rect: rect)
        outerPath.lineWidth = 1
        Theme.current.surface2.setStroke()
        outerPath.stroke()

        guard let ts = textStorage else { return }
        let charRange = characterRange(forGlyphRange: glyphRange, actualGlyphRange: nil)
        let text = ts.string as NSString
        let tableText = text.substring(with: charRange)
        let lines = tableText.components(separatedBy: "\n").filter { !$0.isEmpty }

        var charOffset = charRange.location
        for (i, line) in lines.enumerated() {
            let lineLen = (line as NSString).length
            if i > 0 {
                let lineGlyphRange = self.glyphRange(forCharacterRange: NSRange(location: charOffset, length: 1), actualCharacterRange: nil)
                let lineRect = boundingRect(forGlyphRange: lineGlyphRange, in: container)
                let y = lineRect.origin.y + origin.y
                let rowLine = NSBezierPath()
                rowLine.move(to: NSPoint(x: rect.origin.x, y: y))
                rowLine.line(to: NSPoint(x: rect.origin.x + rect.size.width, y: y))
                rowLine.lineWidth = 0.5
                Theme.current.surface2.setStroke()
                rowLine.stroke()
            }
            charOffset += lineLen + 1
        }

        if let firstLine = lines.first {
            let nsFirstLine = firstLine as NSString
            var pipeOffsets: [Int] = []
            for i in 0..<nsFirstLine.length {
                if nsFirstLine.character(at: i) == UInt16(UnicodeScalar("|").value) {
                    pipeOffsets.append(i)
                }
            }
            if pipeOffsets.count > 2 {
                for pi in 1..<(pipeOffsets.count - 1) {
                    let charPos = charRange.location + pipeOffsets[pi]
                    let pipeGlyph = self.glyphRange(forCharacterRange: NSRange(location: charPos, length: 1), actualCharacterRange: nil)
                    let pipeRect = boundingRect(forGlyphRange: pipeGlyph, in: container)
                    let x = pipeRect.origin.x + origin.x + pipeRect.size.width / 2
                    let colLine = NSBezierPath()
                    colLine.move(to: NSPoint(x: x, y: rect.origin.y))
                    colLine.line(to: NSPoint(x: x, y: rect.origin.y + rect.size.height))
                    colLine.lineWidth = 0.5
                    Theme.current.surface2.setStroke()
                    colLine.stroke()
                }
            }

            if lines.count > 1 {
                let firstLineRange = NSRange(location: charRange.location, length: nsFirstLine.length)
                let headerGlyphRange = self.glyphRange(forCharacterRange: firstLineRange, actualCharacterRange: nil)
                var headerRect = boundingRect(forGlyphRange: headerGlyphRange, in: container)
                headerRect.origin.x = rect.origin.x
                headerRect.origin.y += origin.y
                headerRect.size.width = rect.size.width
                Theme.current.surface0.setFill()
                headerRect.fill()
            }
        }
    }
}

// MARK: - Interactive Table Component

enum TableAlignment {
    case left, center, right
}

struct ParsedTable {
    var headers: [String]
    var alignments: [TableAlignment]
    var rows: [[String]]
    var sourceRange: NSRange
}

func parseMarkdownTable(from text: NSString, range: NSRange) -> ParsedTable? {
    let tableText = text.substring(with: range)
    let lines = tableText.components(separatedBy: "\n").filter { !$0.isEmpty }
    guard lines.count >= 2 else { return nil }

    func parseCells(_ line: String) -> [String] {
        var trimmed = line.trimmingCharacters(in: .whitespaces)
        if trimmed.hasPrefix("|") { trimmed = String(trimmed.dropFirst()) }
        if trimmed.hasSuffix("|") { trimmed = String(trimmed.dropLast()) }
        return trimmed.components(separatedBy: "|").map { $0.trimmingCharacters(in: .whitespaces) }
    }

    let headers = parseCells(lines[0])
    guard headers.count > 0 else { return nil }

    var sepIdx = 1
    var alignments: [TableAlignment] = Array(repeating: .left, count: headers.count)

    if sepIdx < lines.count && isTableSeparator(lines[sepIdx].trimmingCharacters(in: .whitespacesAndNewlines)) {
        let sepCells = parseCells(lines[sepIdx])
        for (i, cell) in sepCells.enumerated() where i < alignments.count {
            let c = cell.trimmingCharacters(in: .whitespaces)
            if c.hasPrefix(":") && c.hasSuffix(":") {
                alignments[i] = .center
            } else if c.hasSuffix(":") {
                alignments[i] = .right
            }
        }
        sepIdx += 1
    }

    var rows: [[String]] = []
    for i in sepIdx..<lines.count {
        let cells = parseCells(lines[i])
        var row = cells
        while row.count < headers.count { row.append("") }
        if row.count > headers.count { row = Array(row.prefix(headers.count)) }
        rows.append(row)
    }

    return ParsedTable(headers: headers, alignments: alignments, rows: rows, sourceRange: range)
}

func rebuildTableMarkdown(_ table: ParsedTable) -> String {
    let colCount = table.headers.count
    var colWidths = Array(repeating: 3, count: colCount)
    for (i, h) in table.headers.enumerated() {
        colWidths[i] = max(colWidths[i], h.count)
    }
    for row in table.rows {
        for (i, cell) in row.enumerated() where i < colCount {
            colWidths[i] = max(colWidths[i], cell.count)
        }
    }

    func formatRow(_ cells: [String]) -> String {
        var parts: [String] = []
        for (i, cell) in cells.enumerated() where i < colCount {
            parts.append(" " + cell.padding(toLength: colWidths[i], withPad: " ", startingAt: 0) + " ")
        }
        return "|" + parts.joined(separator: "|") + "|"
    }

    var lines: [String] = []
    lines.append(formatRow(table.headers))

    var sepParts: [String] = []
    for i in 0..<colCount {
        let w = colWidths[i]
        var dash = String(repeating: "-", count: w)
        switch table.alignments[i] {
        case .left:   dash = " " + dash + " "
        case .center: dash = ":" + dash + ":"
        case .right:  dash = " " + dash + ":"
        }
        sepParts.append(dash)
    }
    lines.append("|" + sepParts.joined(separator: "|") + "|")

    for row in table.rows {
        lines.append(formatRow(row))
    }

    return lines.joined(separator: "\n")
}

class MarkdownTableView: NSView, NSTextFieldDelegate {
    var table: ParsedTable
    weak var textView: NSTextView?
    var onTableChanged: ((ParsedTable) -> Void)?

    private var cellFields: [[NSTextField]] = []
    private let cellHeight: CGFloat = 26
    private let cellPadding: CGFloat = 4
    private let headerHeight: CGFloat = 28

    init(table: ParsedTable, width: CGFloat) {
        self.table = table
        super.init(frame: .zero)
        wantsLayer = true
        layer?.backgroundColor = Theme.current.base.cgColor
        layer?.cornerRadius = 4
        layer?.borderWidth = 1
        layer?.borderColor = Theme.current.surface2.cgColor
        buildGrid(width: width)
    }

    required init?(coder: NSCoder) { fatalError() }

    private func buildGrid(width: CGFloat) {
        subviews.forEach { $0.removeFromSuperview() }
        cellFields = []

        let colCount = table.headers.count
        guard colCount > 0 else { return }
        let colWidth = (width - CGFloat(colCount + 1)) / CGFloat(colCount)
        let totalRows = 1 + table.rows.count
        let totalHeight = headerHeight + CGFloat(table.rows.count) * cellHeight

        frame.size = NSSize(width: width, height: totalHeight)

        // Header row
        let headerBg = NSView(frame: NSRect(x: 0, y: totalHeight - headerHeight, width: width, height: headerHeight))
        headerBg.wantsLayer = true
        headerBg.layer?.backgroundColor = Theme.current.surface0.cgColor
        addSubview(headerBg)

        var headerFields: [NSTextField] = []
        for (col, header) in table.headers.enumerated() {
            let x = CGFloat(col) * colWidth + CGFloat(col + 1)
            let field = makeCell(text: header, frame: NSRect(x: x, y: totalHeight - headerHeight + 2, width: colWidth, height: headerHeight - 4), isHeader: true, row: -1, col: col)
            addSubview(field)
            headerFields.append(field)
        }
        cellFields.append(headerFields)

        // Data rows
        for (rowIdx, row) in table.rows.enumerated() {
            var rowFields: [NSTextField] = []
            let y = totalHeight - headerHeight - CGFloat(rowIdx + 1) * cellHeight
            for (col, cell) in row.enumerated() where col < colCount {
                let x = CGFloat(col) * colWidth + CGFloat(col + 1)
                let field = makeCell(text: cell, frame: NSRect(x: x, y: y + 2, width: colWidth, height: cellHeight - 4), isHeader: false, row: rowIdx, col: col)
                addSubview(field)
                rowFields.append(field)
            }
            while rowFields.count < colCount {
                let col = rowFields.count
                let x = CGFloat(col) * colWidth + CGFloat(col + 1)
                let field = makeCell(text: "", frame: NSRect(x: x, y: y + 2, width: colWidth, height: cellHeight - 4), isHeader: false, row: rowIdx, col: col)
                addSubview(field)
                rowFields.append(field)
            }
            cellFields.append(rowFields)
        }

        // Grid lines
        for i in 1..<colCount {
            let x = CGFloat(i) * (colWidth + 1)
            let line = NSView(frame: NSRect(x: x, y: 0, width: 1, height: totalHeight))
            line.wantsLayer = true
            line.layer?.backgroundColor = Theme.current.surface2.cgColor
            addSubview(line)
        }
        for i in 0..<totalRows {
            let y = totalHeight - headerHeight - CGFloat(i) * cellHeight
            let line = NSView(frame: NSRect(x: 0, y: y, width: width, height: 1))
            line.wantsLayer = true
            line.layer?.backgroundColor = Theme.current.surface2.cgColor
            addSubview(line)
        }
    }

    private func makeCell(text: String, frame: NSRect, isHeader: Bool, row: Int, col: Int) -> NSTextField {
        let field = NSTextField(frame: frame)
        field.stringValue = text
        field.isEditable = true
        field.isBordered = false
        field.drawsBackground = false
        field.font = isHeader
            ? NSFontManager.shared.convert(Theme.editorFont, toHaveTrait: .boldFontMask)
            : Theme.editorFont
        field.textColor = Theme.current.text
        field.focusRingType = .none
        field.cell?.truncatesLastVisibleLine = true
        field.tag = (row + 1) * 1000 + col
        field.delegate = self
        if let align = table.alignments[safe: col] {
            switch align {
            case .left:   field.alignment = .left
            case .center: field.alignment = .center
            case .right:  field.alignment = .right
            }
        }
        return field
    }

    func controlTextDidEndEditing(_ obj: Notification) {
        guard let field = obj.object as? NSTextField else { return }
        let tag = field.tag
        let row = tag / 1000 - 1
        let col = tag % 1000

        if row == -1 {
            guard col < table.headers.count else { return }
            table.headers[col] = field.stringValue
        } else {
            guard row < table.rows.count, col < table.rows[row].count else { return }
            table.rows[row][col] = field.stringValue
        }
        onTableChanged?(table)

        if let movement = obj.userInfo?["NSTextMovement"] as? Int, movement == NSTabTextMovement {
            let nextCol = col + 1
            let nextRow = row + (nextCol >= table.headers.count ? 1 : 0)
            let actualCol = nextCol % table.headers.count
            let actualRow = nextRow
            let fieldRow = actualRow + 1
            if fieldRow < cellFields.count, actualCol < cellFields[fieldRow].count {
                window?.makeFirstResponder(cellFields[fieldRow][actualCol])
            }
        }
    }

    func control(_ control: NSControl, textView tv: NSTextView, doCommandBy commandSelector: Selector) -> Bool {
        if commandSelector == #selector(NSResponder.insertNewline(_:)) {
            guard let field = control as? NSTextField else { return false }
            let tag = field.tag
            let row = tag / 1000 - 1
            let col = tag % 1000
            _ = row; _ = col

            table.rows.append(Array(repeating: "", count: table.headers.count))
            onTableChanged?(table)

            let width = frame.width
            buildGrid(width: width)
            needsLayout = true
            return true
        }
        return false
    }
}

private extension Array {
    subscript(safe index: Int) -> Element? {
        indices.contains(index) ? self[index] : nil
    }
}

// MARK: - File Embed Attachment Cell

class FileEmbedCell: NSTextAttachmentCell {
    let filePath: String
    let fileName: String
    private let fileIcon: NSImage

    init(filePath: String) {
        self.filePath = filePath
        self.fileName = (filePath as NSString).lastPathComponent
        self.fileIcon = NSWorkspace.shared.icon(forFile: filePath)
        self.fileIcon.size = NSSize(width: 16, height: 16)
        super.init()
    }

    required init(coder: NSCoder) { fatalError() }

    override func cellSize() -> NSSize {
        let textSize = (fileName as NSString).size(withAttributes: [.font: Theme.editorFont])
        return NSSize(width: 16 + 8 + textSize.width + 16, height: max(24, textSize.height + 8))
    }

    override func draw(withFrame cellFrame: NSRect, in controlView: NSView?) {
        let path = NSBezierPath(roundedRect: cellFrame.insetBy(dx: 1, dy: 1), xRadius: 4, yRadius: 4)
        Theme.current.surface1.setFill()
        path.fill()
        Theme.current.surface2.setStroke()
        path.lineWidth = 1
        path.stroke()

        let iconRect = NSRect(x: cellFrame.origin.x + 6, y: cellFrame.origin.y + (cellFrame.height - 16) / 2, width: 16, height: 16)
        fileIcon.draw(in: iconRect)

        let textRect = NSRect(x: iconRect.maxX + 4, y: cellFrame.origin.y + (cellFrame.height - 16) / 2, width: cellFrame.width - 30, height: 16)
        let attrs: [NSAttributedString.Key: Any] = [
            .font: Theme.editorFont,
            .foregroundColor: Theme.current.text
        ]
        fileName.draw(in: textRect, withAttributes: attrs)
    }

    override func wantsToTrackMouse() -> Bool { true }

    override func trackMouse(with theEvent: NSEvent, in cellFrame: NSRect, of controlView: NSView?, untilMouseUp flag: Bool) -> Bool {
        if theEvent.clickCount >= 1 {
            NSWorkspace.shared.open(URL(fileURLWithPath: filePath))
        }
        return true
    }
}

// MARK: - Title View

struct TitleView: View {
    @Binding var titleLine: String
    @State private var isEditing = false
    @State private var editText = ""
    var onCommitAndFocusEditor: (() -> Void)?

    private var displayTitle: String {
        let stripped = titleLine.trimmingCharacters(in: .whitespaces)
        if stripped.hasPrefix("# ") {
            return String(stripped.dropFirst(2))
        }
        return stripped
    }

    var body: some View {
        HStack {
            if isEditing {
                TitleTextField(
                    text: $editText,
                    onCommit: { commitEdit() },
                    onEscape: { commitEdit() }
                )
                .font(.system(size: 24, weight: .bold))
                .foregroundColor(Color(ns: Theme.current.text))
                .padding(.horizontal, 58)
                .padding(.top, 16)
                .padding(.bottom, 8)
            } else {
                Text(displayTitle.isEmpty ? "Untitled" : displayTitle)
                    .font(.system(size: 24, weight: .bold))
                    .foregroundColor(displayTitle.isEmpty
                        ? Color(ns: Theme.current.overlay0)
                        : Color(ns: Theme.current.text))
                    .frame(maxWidth: .infinity, alignment: .leading)
                    .padding(.horizontal, 58)
                    .padding(.top, 16)
                    .padding(.bottom, 8)
                    .contentShape(Rectangle())
                    .onTapGesture(count: 2) {
                        editText = titleLine
                        isEditing = true
                    }
            }
            Spacer()
        }
        .background(Color(ns: Theme.current.base))
        .onReceive(NotificationCenter.default.publisher(for: .focusTitle)) { _ in
            editText = titleLine
            isEditing = true
        }
    }

    private func commitEdit() {
        titleLine = editText
        isEditing = false
        onCommitAndFocusEditor?()
    }
}

struct TitleTextField: NSViewRepresentable {
    @Binding var text: String
    var onCommit: () -> Void
    var onEscape: () -> Void

    func makeCoordinator() -> Coordinator { Coordinator(self) }

    func makeNSView(context: Context) -> NSTextField {
        let field = NSTextField()
        field.isBordered = false
        field.drawsBackground = false
        field.font = NSFont.systemFont(ofSize: 24, weight: .bold)
        field.textColor = Theme.current.text
        field.focusRingType = .none
        field.stringValue = text
        field.delegate = context.coordinator
        field.cell?.lineBreakMode = .byTruncatingTail
        DispatchQueue.main.async {
            field.window?.makeFirstResponder(field)
            field.currentEditor()?.selectAll(nil)
        }
        return field
    }

    func updateNSView(_ field: NSTextField, context: Context) {
        if field.stringValue != text {
            field.stringValue = text
        }
    }

    class Coordinator: NSObject, NSTextFieldDelegate {
        var parent: TitleTextField
        init(_ parent: TitleTextField) { self.parent = parent }

        func controlTextDidChange(_ obj: Notification) {
            guard let field = obj.object as? NSTextField else { return }
            parent.text = field.stringValue
        }

        func control(_ control: NSControl, textView: NSTextView, doCommandBy sel: Selector) -> Bool {
            if sel == #selector(NSResponder.insertNewline(_:)) {
                parent.onCommit()
                return true
            }
            if sel == #selector(NSResponder.cancelOperation(_:)) {
                parent.onEscape()
                return true
            }
            return false
        }
    }
}

// MARK: - Editor View

struct EditorView: View {
    @ObservedObject var state: AppState
    @State private var titleIsEditing = false

    private var titleBinding: Binding<String> {
        Binding(
            get: {
                let lines = state.documentText.components(separatedBy: "\n")
                return lines.first ?? ""
            },
            set: { newTitle in
                let lines = state.documentText.components(separatedBy: "\n")
                var rest = Array(lines.dropFirst())
                if rest.isEmpty && state.documentText.isEmpty {
                    rest = []
                }
                state.documentText = ([newTitle] + rest).joined(separator: "\n")
            }
        )
    }

    private var bodyBinding: Binding<String> {
        Binding(
            get: {
                let text = state.documentText
                guard let firstNewline = text.firstIndex(of: "\n") else {
                    return ""
                }
                return String(text[text.index(after: firstNewline)...])
            },
            set: { newBody in
                let lines = state.documentText.components(separatedBy: "\n")
                let title = lines.first ?? ""
                state.documentText = title + "\n" + newBody
            }
        )
    }

    var body: some View {
        VStack(spacing: 0) {
            TitleView(
                titleLine: titleBinding,
                onCommitAndFocusEditor: {
                    NotificationCenter.default.post(name: .focusEditor, object: nil)
                }
            )
            EditorTextView(
                text: bodyBinding,
                evalResults: offsetEvalResults(state.evalResults),
                onEvaluate: { state.evaluate() },
                onBackspaceAtStart: {
                    NotificationCenter.default.post(name: .focusTitle, object: nil)
                }
            )
        }
    }

    private func offsetEvalResults(_ results: [Int: String]) -> [Int: String] {
        var shifted: [Int: String] = [:]
        for (key, val) in results where key > 0 {
            shifted[key - 1] = val
        }
        return shifted
    }
}

struct EditorTextView: NSViewRepresentable {
    @Binding var text: String
    var evalResults: [Int: String]
    var onEvaluate: () -> Void
    var onBackspaceAtStart: (() -> Void)? = nil

    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }

    func makeNSView(context: Context) -> NSScrollView {
        let scrollView = NSTextView.scrollableTextView()
        let defaultTV = scrollView.documentView as! NSTextView

        // Build LineNumberTextView reusing the default text container
        let tc = defaultTV.textContainer!
        tc.replaceLayoutManager(MarkdownLayoutManager())

        let textView = LineNumberTextView(frame: defaultTV.frame, textContainer: tc)
        textView.minSize = defaultTV.minSize
        textView.maxSize = defaultTV.maxSize
        textView.isVerticallyResizable = defaultTV.isVerticallyResizable
        textView.isHorizontallyResizable = defaultTV.isHorizontallyResizable
        textView.autoresizingMask = defaultTV.autoresizingMask

        textView.isEditable = true
        textView.isSelectable = true
        textView.allowsUndo = true
        textView.isRichText = true
        textView.usesFindBar = true
        textView.isIncrementalSearchingEnabled = true
        textView.font = Theme.editorFont
        textView.textColor = Theme.current.text
        textView.backgroundColor = Theme.current.base
        textView.insertionPointColor = Theme.current.text
        textView.selectedTextAttributes = [
            .backgroundColor: Theme.current.surface1
        ]
        textView.isAutomaticQuoteSubstitutionEnabled = false
        textView.isAutomaticDashSubstitutionEnabled = false
        textView.isAutomaticTextReplacementEnabled = false
        textView.isAutomaticSpellingCorrectionEnabled = false
        textView.smartInsertDeleteEnabled = false
        textView.isAutomaticLinkDetectionEnabled = false

        textView.textContainerInset = NSSize(width: 4, height: 8)
        textView.textContainer?.widthTracksTextView = false
        textView.registerForDraggedTypes([.fileURL])

        scrollView.documentView = textView

        textView.string = text
        textView.evalResults = evalResults
        textView.delegate = context.coordinator
        context.coordinator.textView = textView

        if let ts = textView.textStorage {
            ts.beginEditing()
            applySyntaxHighlighting(to: ts)
            ts.endEditing()
        }
        textView.typingAttributes = [
            .font: Theme.editorFont,
            .foregroundColor: Theme.current.text
        ]
        updateBlockRanges(for: textView)

        DispatchQueue.main.async {
            context.coordinator.triggerImageUpdate()
            context.coordinator.triggerTableUpdate()
        }

        return scrollView
    }

    func updateNSView(_ scrollView: NSScrollView, context: Context) {
        guard let textView = scrollView.documentView as? LineNumberTextView else { return }
        if textView.string != text {
            let selectedRanges = textView.selectedRanges
            textView.string = text
            if let ts = textView.textStorage {
                ts.beginEditing()
                applySyntaxHighlighting(to: ts)
                ts.endEditing()
            }
            textView.selectedRanges = selectedRanges
            updateBlockRanges(for: textView)
        }
        textView.backgroundColor = Theme.current.base
        textView.insertionPointColor = Theme.current.text
        textView.typingAttributes = [
            .font: Theme.editorFont,
            .foregroundColor: Theme.current.text
        ]

        textView.evalResults = evalResults
        textView.needsDisplay = true
    }

    class Coordinator: NSObject, NSTextViewDelegate {
        var parent: EditorTextView
        weak var textView: NSTextView?
        private var isUpdatingImages = false
        private var isUpdatingTables = false
        private var embeddedTableViews: [MarkdownTableView] = []
        private var focusObserver: NSObjectProtocol?
        private var settingsObserver: NSObjectProtocol?

        init(_ parent: EditorTextView) {
            self.parent = parent
            super.init()
            focusObserver = NotificationCenter.default.addObserver(
                forName: .focusEditor, object: nil, queue: .main
            ) { [weak self] _ in
                guard let tv = self?.textView else { return }
                tv.window?.makeFirstResponder(tv)
                tv.setSelectedRange(NSRange(location: 0, length: 0))
            }
            settingsObserver = NotificationCenter.default.addObserver(
                forName: .settingsChanged, object: nil, queue: .main
            ) { [weak self] _ in
                guard let tv = self?.textView, let ts = tv.textStorage else { return }
                let palette = Theme.current
                tv.backgroundColor = palette.base
                tv.insertionPointColor = palette.text
                tv.selectedTextAttributes = [.backgroundColor: palette.surface1]
                tv.typingAttributes = [
                    .font: Theme.editorFont,
                    .foregroundColor: palette.text
                ]
                ts.beginEditing()
                applySyntaxHighlighting(to: ts)
                ts.endEditing()
                tv.needsDisplay = true
            }
        }

        deinit {
            if let obs = focusObserver {
                NotificationCenter.default.removeObserver(obs)
            }
            if let obs = settingsObserver {
                NotificationCenter.default.removeObserver(obs)
            }
        }

        func textDidChange(_ notification: Notification) {
            guard let tv = textView, let ts = tv.textStorage else { return }
            if isUpdatingImages || isUpdatingTables { return }
            parent.text = tv.string
            let sel = tv.selectedRanges
            ts.beginEditing()
            applySyntaxHighlighting(to: ts)
            ts.endEditing()
            tv.typingAttributes = [
                .font: Theme.editorFont,
                .foregroundColor: Theme.current.text
            ]
            tv.selectedRanges = sel
            updateBlockRanges(for: tv)
            tv.needsDisplay = true

            DispatchQueue.main.async { [weak self] in
                self?.updateInlineImages()
                self?.updateEmbeddedTables()
            }
        }

        func textView(_ textView: NSTextView, doCommandBy commandSelector: Selector) -> Bool {
            if commandSelector == #selector(NSResponder.insertNewline(_:)) {
                textView.insertNewlineIgnoringFieldEditor(nil)
                DispatchQueue.main.async { [weak self] in
                    self?.parent.onEvaluate()
                }
                return true
            }
            if commandSelector == #selector(NSResponder.deleteBackward(_:)) {
                if textView.selectedRange().location == 0 && textView.selectedRange().length == 0 {
                    parent.onBackspaceAtStart?()
                    return true
                }
            }
            return false
        }

        func textView(_ textView: NSTextView, clickedOnLink link: Any, at charIndex: Int) -> Bool {
            var urlString: String?
            if let url = link as? URL {
                urlString = url.absoluteString
            } else if let str = link as? String {
                urlString = str
            }
            guard let str = urlString, let url = URL(string: str) else { return false }
            NSWorkspace.shared.open(url)
            return true
        }

        func triggerImageUpdate() {
            updateInlineImages()
        }

        func triggerTableUpdate() {
            updateEmbeddedTables()
        }

        // MARK: - Embedded Tables

        private func updateEmbeddedTables() {
            guard let tv = textView, let lm = tv.layoutManager as? MarkdownLayoutManager,
                  let tc = tv.textContainer else { return }

            for tableView in embeddedTableViews {
                tableView.removeFromSuperview()
            }
            embeddedTableViews.removeAll()

            let text = tv.string as NSString
            for block in lm.blockRanges {
                guard case .tableBlock = block.kind else { continue }
                guard let parsed = parseMarkdownTable(from: text, range: block.range) else { continue }

                let glyphRange = lm.glyphRange(forCharacterRange: block.range, actualCharacterRange: nil)
                var rect = lm.boundingRect(forGlyphRange: glyphRange, in: tc)
                rect.origin.x += tv.textContainerInset.width
                rect.origin.y += tv.textContainerInset.height

                let tableWidth = tc.containerSize.width - 8
                let tableView = MarkdownTableView(table: parsed, width: tableWidth)
                tableView.frame.origin = NSPoint(x: rect.origin.x + 4, y: rect.origin.y)
                tableView.textView = tv

                tableView.onTableChanged = { [weak self] updatedTable in
                    self?.applyTableEdit(updatedTable)
                }

                tv.addSubview(tableView)
                embeddedTableViews.append(tableView)
            }
        }

        private func applyTableEdit(_ table: ParsedTable) {
            guard let tv = textView, let ts = tv.textStorage else { return }
            let newMarkdown = rebuildTableMarkdown(table)
            let range = table.sourceRange
            guard NSMaxRange(range) <= ts.length else { return }

            isUpdatingTables = true
            let sel = tv.selectedRanges
            ts.beginEditing()
            ts.replaceCharacters(in: range, with: newMarkdown)
            applySyntaxHighlighting(to: ts)
            ts.endEditing()
            tv.selectedRanges = sel
            parent.text = tv.string
            updateBlockRanges(for: tv)
            isUpdatingTables = false
        }

        private static let imageRegex: NSRegularExpression? = {
            try? NSRegularExpression(pattern: "!\\[[^\\]]*\\]\\(([^)]+)\\)")
        }()

        private func updateInlineImages() {
            guard let tv = textView, let ts = tv.textStorage else { return }
            guard let regex = Coordinator.imageRegex else { return }

            let text = ts.string
            let nsText = text as NSString
            let fullRange = NSRange(location: 0, length: nsText.length)

            let existingAttachmentRanges = findExistingImageAttachments(in: ts)
            let matches = regex.matches(in: text, range: fullRange)

            var resolvedPaths: [String] = []
            for match in matches {
                let urlRange = match.range(at: 1)
                let rawPath = nsText.substring(with: urlRange)
                if let resolved = resolveLocalImagePath(rawPath), FileManager.default.fileExists(atPath: resolved) {
                    resolvedPaths.append(resolved)
                }
            }

            let neededSet = Set(resolvedPaths)
            let existingSet = Set(existingAttachmentRanges.map { $0.1 })
            if neededSet == existingSet { return }

            isUpdatingImages = true
            ts.beginEditing()

            for (range, _) in existingAttachmentRanges.reversed() {
                ts.deleteCharacters(in: range)
            }

            let recalcText = ts.string
            let recalcNS = recalcText as NSString
            let recalcFull = NSRange(location: 0, length: recalcNS.length)
            let recalcMatches = regex.matches(in: recalcText, range: recalcFull)

            var offset = 0
            for match in recalcMatches {
                let urlRange = NSRange(location: match.range(at: 1).location + offset, length: match.range(at: 1).length)
                let rawPath = recalcNS.substring(with: NSRange(location: urlRange.location, length: urlRange.length))
                guard let resolved = resolveLocalImagePath(rawPath),
                      FileManager.default.fileExists(atPath: resolved),
                      let image = NSImage(contentsOfFile: resolved) else { continue }

                let maxWidth: CGFloat = min(600, tv.bounds.width - 40)
                let ratio = image.size.width > maxWidth ? maxWidth / image.size.width : 1.0
                let displaySize = NSSize(
                    width: image.size.width * ratio,
                    height: image.size.height * ratio
                )
                image.size = displaySize

                let attachment = NSTextAttachment()
                let cell = NSTextAttachmentCell(imageCell: image)
                attachment.attachmentCell = cell

                let attachStr = NSMutableAttributedString(string: "\n")
                attachStr.append(NSAttributedString(attachment: attachment))
                attachStr.addAttribute(.toolTip, value: resolved, range: NSRange(location: 1, length: 1))

                let lineEnd = NSMaxRange(match.range) + offset
                let insertAt = min(lineEnd, ts.length)
                ts.insert(attachStr, at: insertAt)
                offset += attachStr.length
            }

            ts.endEditing()
            isUpdatingImages = false
        }

        private func findExistingImageAttachments(in textStorage: NSTextStorage) -> [(NSRange, String)] {
            var results: [(NSRange, String)] = []
            let fullRange = NSRange(location: 0, length: textStorage.length)
            textStorage.enumerateAttribute(.attachment, in: fullRange) { value, range, _ in
                if value is NSTextAttachment {
                    var extRange = range
                    if extRange.location > 0 {
                        let prev = NSRange(location: extRange.location - 1, length: 1)
                        let ch = (textStorage.string as NSString).substring(with: prev)
                        if ch == "\n" {
                            extRange = NSRange(location: prev.location, length: extRange.length + 1)
                        }
                    }
                    let tip = textStorage.attribute(.toolTip, at: range.location, effectiveRange: nil) as? String ?? ""
                    results.append((extRange, tip))
                }
            }
            return results
        }
    }
}

// MARK: - Block Range Detection

private let checkboxPattern: NSRegularExpression? = {
    try? NSRegularExpression(pattern: "\\[[ xX]\\]")
}()

func updateBlockRanges(for textView: NSTextView) {
    guard let lm = textView.layoutManager as? MarkdownLayoutManager else { return }
    let text = textView.string as NSString
    guard text.length > 0 else {
        lm.blockRanges = []
        return
    }

    var blocks: [MarkdownLayoutManager.BlockRange] = []
    var lineStart = 0
    var openFence: Int? = nil
    var blockquoteStart: Int? = nil
    var blockquoteEnd: Int = 0
    var tableStart: Int? = nil
    var tableEnd: Int = 0
    var tableColumns: Int = 0

    while lineStart < text.length {
        let lineRange = text.lineRange(for: NSRange(location: lineStart, length: 0))
        let line = text.substring(with: lineRange)
        let trimmed = line.trimmingCharacters(in: .whitespacesAndNewlines)

        if openFence == nil && trimmed.hasPrefix("```") {
            openFence = lineRange.location
        } else if openFence != nil && trimmed == "```" {
            let range = NSRange(location: openFence!, length: NSMaxRange(lineRange) - openFence!)
            blocks.append(.init(range: range, kind: .codeBlock))
            openFence = nil
            lineStart = NSMaxRange(lineRange)
            continue
        }

        if openFence != nil {
            lineStart = NSMaxRange(lineRange)
            continue
        }

        if trimmed.hasPrefix("> ") || trimmed == ">" {
            if blockquoteStart == nil { blockquoteStart = lineRange.location }
            blockquoteEnd = NSMaxRange(lineRange)
        } else {
            if let start = blockquoteStart {
                blocks.append(.init(range: NSRange(location: start, length: blockquoteEnd - start), kind: .blockquote))
                blockquoteStart = nil
            }
        }

        if isHorizontalRule(trimmed) && openFence == nil {
            blocks.append(.init(range: lineRange, kind: .horizontalRule))
        }

        // Task list checkboxes
        let taskPrefixes = ["- [ ] ", "- [x] ", "- [X] ", "* [ ] ", "* [x] ", "* [X] ", "+ [ ] ", "+ [x] ", "+ [X] "]
        let strippedLine = trimmed
        for prefix in taskPrefixes {
            if strippedLine.hasPrefix(prefix) {
                let checked = prefix.contains("x") || prefix.contains("X")
                if let regex = checkboxPattern,
                   let match = regex.firstMatch(in: text as String, range: lineRange) {
                    blocks.append(.init(range: match.range, kind: .checkbox(checked: checked)))
                }
                break
            }
        }

        if trimmed.hasPrefix("|") {
            if tableStart == nil {
                tableStart = lineRange.location
                tableColumns = trimmed.filter({ $0 == "|" }).count - 1
                if tableColumns < 1 { tableColumns = 1 }
            }
            tableEnd = NSMaxRange(lineRange)
        } else {
            if let start = tableStart {
                blocks.append(.init(range: NSRange(location: start, length: tableEnd - start), kind: .tableBlock(columns: tableColumns)))
                tableStart = nil
                tableColumns = 0
            }
        }

        lineStart = NSMaxRange(lineRange)
    }

    if let start = blockquoteStart {
        blocks.append(.init(range: NSRange(location: start, length: blockquoteEnd - start), kind: .blockquote))
    }
    if let start = tableStart {
        blocks.append(.init(range: NSRange(location: start, length: tableEnd - start), kind: .tableBlock(columns: tableColumns)))
    }

    lm.blockRanges = blocks

    let fullRange = NSRange(location: 0, length: text.length)
    lm.invalidateDisplay(forCharacterRange: fullRange)
}

// MARK: - Syntax Highlighting

private let syntaxKeywords: Set<String> = [
    "let", "fn", "if", "else", "for", "map", "cast", "plot", "sch"
]

private let syntaxOperatorChars = CharacterSet(charactersIn: "+-*/=^<>!(){}[]:,")

func applySyntaxHighlighting(to textStorage: NSTextStorage) {
    let text = textStorage.string
    let fullRange = NSRange(location: 0, length: (text as NSString).length)
    let palette = Theme.current
    let syn = Theme.syntax

    let baseFont = Theme.editorFont
    let baseAttrs: [NSAttributedString.Key: Any] = [
        .font: baseFont,
        .foregroundColor: palette.text
    ]
    textStorage.setAttributes(baseAttrs, range: fullRange)

    let fencedRanges = highlightFencedCodeBlocks(textStorage: textStorage, palette: palette, baseFont: baseFont)
    let tableHeaderLines = findTableHeaderLines(textStorage: textStorage, fencedRanges: fencedRanges)

    let nsText = text as NSString
    var lineStart = 0

    while lineStart < nsText.length {
        let lineRange = nsText.lineRange(for: NSRange(location: lineStart, length: 0))

        if isInsideFencedBlock(lineRange, fencedRanges: fencedRanges) {
            lineStart = NSMaxRange(lineRange)
            continue
        }

        let line = nsText.substring(with: lineRange)
        let trimmed = line.trimmingCharacters(in: .whitespaces)
        let isTableHeader = tableHeaderLines.contains(lineRange.location)

        if highlightMarkdownLine(trimmed, line: line, lineRange: lineRange, textStorage: textStorage, baseFont: baseFont, palette: palette, isTableHeader: isTableHeader) {
            highlightInlineCode(textStorage: textStorage, lineRange: lineRange, palette: palette, baseFont: baseFont)
            highlightStrikethrough(textStorage: textStorage, lineRange: lineRange, palette: palette)
            highlightFootnoteRefs(textStorage: textStorage, lineRange: lineRange, palette: palette)
            lineStart = NSMaxRange(lineRange)
            continue
        }

        if isCordialLine(trimmed) {
            highlightCodeLine(line, lineRange: lineRange, textStorage: textStorage, syn: syn)
        }
        highlightInlineCode(textStorage: textStorage, lineRange: lineRange, palette: palette, baseFont: baseFont)
        highlightStrikethrough(textStorage: textStorage, lineRange: lineRange, palette: palette)
        highlightFootnoteRefs(textStorage: textStorage, lineRange: lineRange, palette: palette)

        lineStart = NSMaxRange(lineRange)
    }

    highlightBlockComments(textStorage: textStorage, syn: syn, baseFont: baseFont)
    highlightLinks(textStorage: textStorage, palette: palette, fencedRanges: fencedRanges)
    highlightImages(textStorage: textStorage, palette: palette, fencedRanges: fencedRanges)
    highlightAutolinks(textStorage: textStorage, palette: palette, fencedRanges: fencedRanges)
}

private func highlightMarkdownLine(_ trimmed: String, line: String, lineRange: NSRange, textStorage: NSTextStorage, baseFont: NSFont, palette: CatppuccinPalette, isTableHeader: Bool = false) -> Bool {
    if trimmed.hasPrefix("### ") {
        let hashRange = (textStorage.string as NSString).range(of: "###", range: lineRange)
        if hashRange.location != NSNotFound {
            textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: hashRange)
            let contentStart = hashRange.location + hashRange.length
            let contentRange = NSRange(location: contentStart, length: NSMaxRange(lineRange) - contentStart)
            if contentRange.length > 0 {
                let h3Font = NSFont.systemFont(ofSize: 15, weight: .bold)
                textStorage.addAttribute(.font, value: h3Font, range: contentRange)
                textStorage.addAttribute(.foregroundColor, value: palette.text, range: contentRange)
            }
        }
        return true
    }

    if trimmed.hasPrefix("## ") {
        let hashRange = (textStorage.string as NSString).range(of: "##", range: lineRange)
        if hashRange.location != NSNotFound {
            textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: hashRange)
            let contentStart = hashRange.location + hashRange.length
            let contentRange = NSRange(location: contentStart, length: NSMaxRange(lineRange) - contentStart)
            if contentRange.length > 0 {
                let h2Font = NSFont.systemFont(ofSize: 18, weight: .bold)
                textStorage.addAttribute(.font, value: h2Font, range: contentRange)
                textStorage.addAttribute(.foregroundColor, value: palette.text, range: contentRange)
            }
        }
        return true
    }

    if trimmed.hasPrefix("# ") {
        let hashRange = (textStorage.string as NSString).range(of: "#", range: lineRange)
        if hashRange.location != NSNotFound {
            textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: hashRange)
            let contentStart = hashRange.location + hashRange.length
            let contentRange = NSRange(location: contentStart, length: NSMaxRange(lineRange) - contentStart)
            if contentRange.length > 0 {
                let h1Font = NSFont.systemFont(ofSize: 22, weight: .bold)
                textStorage.addAttribute(.font, value: h1Font, range: contentRange)
                textStorage.addAttribute(.foregroundColor, value: palette.text, range: contentRange)
            }
        }
        return true
    }

    if trimmed.hasPrefix("> ") || trimmed == ">" {
        textStorage.addAttribute(.foregroundColor, value: palette.overlay2, range: lineRange)
        let indent = NSMutableParagraphStyle()
        indent.headIndent = 24
        indent.firstLineHeadIndent = 24
        textStorage.addAttribute(.paragraphStyle, value: indent, range: lineRange)
        let gtRange = (textStorage.string as NSString).range(of: ">", options: [], range: lineRange)
        if gtRange.location != NSNotFound {
            textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: gtRange)
        }
        return true
    }

    if isHorizontalRule(trimmed) {
        textStorage.addAttribute(.foregroundColor, value: palette.base, range: lineRange)
        textStorage.addAttribute(.font, value: NSFont.systemFont(ofSize: 0.01), range: lineRange)
        return true
    }

    // Footnote definition
    if trimmed.hasPrefix("[^") && trimmed.contains("]:") {
        highlightFootnoteDefinition(textStorage: textStorage, lineRange: lineRange, palette: palette)
        return true
    }

    // Task list (check before generic unordered list)
    if trimmed.hasPrefix("- [ ] ") || trimmed.hasPrefix("- [x] ") || trimmed.hasPrefix("- [X] ") ||
       trimmed.hasPrefix("* [ ] ") || trimmed.hasPrefix("* [x] ") || trimmed.hasPrefix("* [X] ") ||
       trimmed.hasPrefix("+ [ ] ") || trimmed.hasPrefix("+ [x] ") || trimmed.hasPrefix("+ [X] ") {
        highlightTaskList(trimmed, lineRange: lineRange, line: line, textStorage: textStorage, palette: palette)
        return true
    }

    // Table rows
    if trimmed.hasPrefix("|") {
        let isSep = isTableSeparator(trimmed)
        highlightTableLine(trimmed, lineRange: lineRange, textStorage: textStorage, palette: palette, baseFont: baseFont, isHeader: isTableHeader, isSeparator: isSep)
        return true
    }

    // Unordered list
    if let regex = try? NSRegularExpression(pattern: "^\\s*[-*+] "),
       regex.firstMatch(in: line, range: NSRange(location: 0, length: (line as NSString).length)) != nil {
        highlightUnorderedList(trimmed, lineRange: lineRange, line: line, textStorage: textStorage, palette: palette)
        return true
    }

    // Ordered list
    if let regex = try? NSRegularExpression(pattern: "^\\s*\\d+\\. "),
       regex.firstMatch(in: line, range: NSRange(location: 0, length: (line as NSString).length)) != nil {
        highlightOrderedList(trimmed, lineRange: lineRange, line: line, textStorage: textStorage, palette: palette)
        return true
    }

    return false
}

private func highlightCodeLine(_ line: String, lineRange: NSRange, textStorage: NSTextStorage, syn: Theme.SyntaxColors) {
    let nsLine = line as NSString
    let baseFont = Theme.editorFont
    let italicFont = NSFontManager.shared.convert(baseFont, toHaveTrait: .italicFontMask)
    let boldFont = NSFontManager.shared.convert(baseFont, toHaveTrait: .boldFontMask)

    let trimmed = line.trimmingCharacters(in: .whitespaces)

    // Line comment
    if let commentRange = findLineComment(nsLine) {
        let absRange = NSRange(location: lineRange.location + commentRange.location, length: commentRange.length)
        textStorage.addAttributes([
            .foregroundColor: syn.comment,
            .font: italicFont
        ], range: absRange)
        highlightCodeTokens(nsLine, inRange: NSRange(location: 0, length: commentRange.location), lineOffset: lineRange.location, textStorage: textStorage, syn: syn)
        return
    }

    // Eval prefix
    if trimmed.hasPrefix("/=") {
        let prefixRange = (textStorage.string as NSString).range(of: "/=", range: lineRange)
        if prefixRange.location != NSNotFound {
            textStorage.addAttribute(.foregroundColor, value: syn.operator, range: prefixRange)
        }
    }

    highlightCodeTokens(nsLine, inRange: NSRange(location: 0, length: nsLine.length), lineOffset: lineRange.location, textStorage: textStorage, syn: syn)

    // Bold markers **text**
    highlightInlineMarkdown(textStorage: textStorage, lineRange: lineRange, pattern: "\\*\\*(.+?)\\*\\*", markerLen: 2, trait: .boldFontMask, font: boldFont)

    // Italic markers *text*
    highlightInlineMarkdown(textStorage: textStorage, lineRange: lineRange, pattern: "(?<!\\*)\\*(?!\\*)(.+?)(?<!\\*)\\*(?!\\*)", markerLen: 1, trait: .italicFontMask, font: italicFont)
}

private func highlightInlineMarkdown(textStorage: NSTextStorage, lineRange: NSRange, pattern: String, markerLen: Int, trait: NSFontTraitMask, font: NSFont) {
    let palette = Theme.current
    guard let regex = try? NSRegularExpression(pattern: pattern) else { return }
    let matches = regex.matches(in: textStorage.string, range: lineRange)
    for match in matches {
        let fullRange = match.range
        let openMarker = NSRange(location: fullRange.location, length: markerLen)
        let closeMarker = NSRange(location: fullRange.location + fullRange.length - markerLen, length: markerLen)
        let contentRange = NSRange(location: fullRange.location + markerLen, length: fullRange.length - markerLen * 2)
        textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: openMarker)
        textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: closeMarker)
        if contentRange.length > 0 {
            textStorage.addAttribute(.font, value: font, range: contentRange)
            textStorage.addAttribute(.foregroundColor, value: palette.text, range: contentRange)
        }
    }
}

private func findLineComment(_ line: NSString) -> NSRange? {
    guard line.length >= 2 else { return nil }
    var i = 0
    var inString = false
    while i < line.length - 1 {
        let ch = line.character(at: i)
        if ch == UInt16(UnicodeScalar("\"").value) {
            inString = !inString
        } else if !inString && ch == UInt16(UnicodeScalar("/").value) && line.character(at: i + 1) == UInt16(UnicodeScalar("/").value) {
            return NSRange(location: i, length: line.length - i)
        }
        i += 1
    }
    return nil
}

private func highlightCodeTokens(_ line: NSString, inRange range: NSRange, lineOffset: Int, textStorage: NSTextStorage, syn: Theme.SyntaxColors) {
    let sub = line.substring(with: range)
    let scanner = Scanner(string: sub)
    scanner.charactersToBeSkipped = nil
    let digitChars = CharacterSet.decimalDigits.union(CharacterSet(charactersIn: "."))
    let identStart = CharacterSet.letters.union(CharacterSet(charactersIn: "_"))
    let identChars = identStart.union(.decimalDigits)

    while !scanner.isAtEnd {
        let pos = scanner.currentIndex

        // String literal
        if scanner.scanString("\"") != nil {
            let startIdx = sub.distance(from: sub.startIndex, to: pos)
            var strContent = "\""
            var escaped = false
            while !scanner.isAtEnd {
                let ch = sub[scanner.currentIndex]
                strContent.append(ch)
                scanner.currentIndex = sub.index(after: scanner.currentIndex)
                if escaped {
                    escaped = false
                    continue
                }
                if ch == "\\" { escaped = true; continue }
                if ch == "\"" { break }
            }
            let absRange = NSRange(location: lineOffset + range.location + startIdx, length: strContent.count)
            textStorage.addAttribute(.foregroundColor, value: syn.string, range: absRange)
            continue
        }

        // Number
        if let numStr = scanner.scanCharacters(from: digitChars) {
            let startIdx = sub.distance(from: sub.startIndex, to: pos)
            let absRange = NSRange(location: lineOffset + range.location + startIdx, length: numStr.count)
            textStorage.addAttribute(.foregroundColor, value: syn.number, range: absRange)
            continue
        }

        // Identifier / keyword
        if let ident = scanner.scanCharacters(from: identChars) {
            if let first = ident.unicodeScalars.first, identStart.contains(first) {
                let startIdx = sub.distance(from: sub.startIndex, to: pos)
                let absRange = NSRange(location: lineOffset + range.location + startIdx, length: ident.count)
                if syntaxKeywords.contains(ident) {
                    textStorage.addAttribute(.foregroundColor, value: syn.keyword, range: absRange)
                }
            }
            continue
        }

        // Operator
        if let op = scanner.scanCharacters(from: syntaxOperatorChars) {
            let startIdx = sub.distance(from: sub.startIndex, to: pos)
            let absRange = NSRange(location: lineOffset + range.location + startIdx, length: op.count)
            textStorage.addAttribute(.foregroundColor, value: syn.operator, range: absRange)
            continue
        }

        // Skip unrecognized character
        scanner.currentIndex = sub.index(after: scanner.currentIndex)
    }
}

private func highlightBlockComments(textStorage: NSTextStorage, syn: Theme.SyntaxColors, baseFont: NSFont) {
    let text = textStorage.string
    let nsText = text as NSString
    let italicFont = NSFontManager.shared.convert(baseFont, toHaveTrait: .italicFontMask)
    let len = nsText.length
    guard len >= 4 else { return }

    var i = 0
    while i < len - 1 {
        if nsText.character(at: i) == 0x2F && nsText.character(at: i + 1) == 0x2A { // /*
            let start = i
            var depth = 1
            i += 2
            while i < len - 1 && depth > 0 {
                let c = nsText.character(at: i)
                let n = nsText.character(at: i + 1)
                if c == 0x2F && n == 0x2A { // /*
                    depth += 1
                    i += 2
                } else if c == 0x2A && n == 0x2F { // */
                    depth -= 1
                    i += 2
                } else {
                    i += 1
                }
            }
            if i > len { i = len }
            let range = NSRange(location: start, length: i - start)
            textStorage.addAttributes([
                .foregroundColor: syn.comment,
                .font: italicFont
            ], range: range)
        } else {
            i += 1
        }
    }
}

// MARK: - Fenced Code Blocks

private func highlightFencedCodeBlocks(textStorage: NSTextStorage, palette: CatppuccinPalette, baseFont: NSFont) -> [NSRange] {
    let text = textStorage.string
    let nsText = text as NSString
    let monoFont = NSFont.monospacedSystemFont(ofSize: baseFont.pointSize, weight: .regular)
    var fencedRanges: [NSRange] = []
    var lineStart = 0
    var openFence: Int? = nil

    while lineStart < nsText.length {
        let lineRange = nsText.lineRange(for: NSRange(location: lineStart, length: 0))
        let line = nsText.substring(with: lineRange)
        let trimmed = line.trimmingCharacters(in: .whitespacesAndNewlines)

        if openFence == nil {
            if trimmed.hasPrefix("```") {
                openFence = lineRange.location
                // Mute the fence line
                textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: lineRange)
                textStorage.addAttribute(.font, value: monoFont, range: lineRange)
                // Language identifier after ```
                if trimmed.count > 3 {
                    let langStart = (nsText as NSString).range(of: "```", range: lineRange)
                    if langStart.location != NSNotFound {
                        let after = langStart.location + langStart.length
                        let langRange = NSRange(location: after, length: NSMaxRange(lineRange) - after)
                        if langRange.length > 0 {
                            textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: langRange)
                        }
                    }
                }
            }
        } else {
            if trimmed == "```" {
                // Close fence
                textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: lineRange)
                textStorage.addAttribute(.font, value: monoFont, range: lineRange)
                let blockRange = NSRange(location: openFence!, length: NSMaxRange(lineRange) - openFence!)
                fencedRanges.append(blockRange)
                openFence = nil
            } else {
                textStorage.addAttribute(.font, value: monoFont, range: lineRange)
                textStorage.addAttribute(.foregroundColor, value: palette.text, range: lineRange)
            }
        }

        lineStart = NSMaxRange(lineRange)
    }

    return fencedRanges
}

private func isInsideFencedBlock(_ lineRange: NSRange, fencedRanges: [NSRange]) -> Bool {
    for fenced in fencedRanges {
        if lineRange.location >= fenced.location && NSMaxRange(lineRange) <= NSMaxRange(fenced) {
            return true
        }
    }
    return false
}

// MARK: - Inline Code

private func highlightInlineCode(textStorage: NSTextStorage, lineRange: NSRange, palette: CatppuccinPalette, baseFont: NSFont) {
    guard let regex = try? NSRegularExpression(pattern: "`([^`]+)`") else { return }
    let monoFont = NSFont.monospacedSystemFont(ofSize: baseFont.pointSize, weight: .regular)
    let matches = regex.matches(in: textStorage.string, range: lineRange)
    for match in matches {
        let fullRange = match.range
        let openTick = NSRange(location: fullRange.location, length: 1)
        let closeTick = NSRange(location: fullRange.location + fullRange.length - 1, length: 1)
        let contentRange = NSRange(location: fullRange.location + 1, length: fullRange.length - 2)
        textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: openTick)
        textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: closeTick)
        if contentRange.length > 0 {
            textStorage.addAttribute(.font, value: monoFont, range: contentRange)
            textStorage.addAttribute(.foregroundColor, value: palette.text, range: contentRange)
            textStorage.addAttribute(.backgroundColor, value: palette.surface0, range: contentRange)
        }
    }
}

// MARK: - Strikethrough

private func highlightStrikethrough(textStorage: NSTextStorage, lineRange: NSRange, palette: CatppuccinPalette) {
    guard let regex = try? NSRegularExpression(pattern: "~~(.+?)~~") else { return }
    let matches = regex.matches(in: textStorage.string, range: lineRange)
    for match in matches {
        let fullRange = match.range
        let openMarker = NSRange(location: fullRange.location, length: 2)
        let closeMarker = NSRange(location: fullRange.location + fullRange.length - 2, length: 2)
        let contentRange = NSRange(location: fullRange.location + 2, length: fullRange.length - 4)
        textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: openMarker)
        textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: closeMarker)
        if contentRange.length > 0 {
            textStorage.addAttribute(.strikethroughStyle, value: NSUnderlineStyle.single.rawValue, range: contentRange)
        }
    }
}

// MARK: - Footnotes

private func highlightFootnoteRefs(textStorage: NSTextStorage, lineRange: NSRange, palette: CatppuccinPalette) {
    // Inline refs: [^label] (but not definitions which start line with [^label]:)
    guard let regex = try? NSRegularExpression(pattern: "\\[\\^[^\\]]+\\](?!:)") else { return }
    let matches = regex.matches(in: textStorage.string, range: lineRange)
    for match in matches {
        textStorage.addAttribute(.foregroundColor, value: palette.blue, range: match.range)
        textStorage.addAttribute(.superscript, value: 1, range: match.range)
    }
}

private func highlightFootnoteDefinition(textStorage: NSTextStorage, lineRange: NSRange, palette: CatppuccinPalette) {
    guard let regex = try? NSRegularExpression(pattern: "^\\[\\^[^\\]]+\\]:") else { return }
    let nsText = textStorage.string as NSString
    let lineContent = nsText.substring(with: lineRange)
    let localRange = NSRange(location: 0, length: (lineContent as NSString).length)
    let matches = regex.matches(in: lineContent, range: localRange)
    for match in matches {
        let absRange = NSRange(location: lineRange.location + match.range.location, length: match.range.length)
        textStorage.addAttribute(.foregroundColor, value: palette.lavender, range: absRange)
    }
}

// MARK: - Tables

private func highlightTableLine(_ trimmed: String, lineRange: NSRange, textStorage: NSTextStorage, palette: CatppuccinPalette, baseFont: NSFont, isHeader: Bool, isSeparator: Bool) {
    let monoFont = NSFont.monospacedSystemFont(ofSize: baseFont.pointSize, weight: .regular)
    let boldMono = NSFontManager.shared.convert(monoFont, toHaveTrait: .boldFontMask)

    textStorage.addAttribute(.font, value: monoFont, range: lineRange)
    textStorage.addAttribute(.foregroundColor, value: palette.text, range: lineRange)

    if isSeparator {
        textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: lineRange)
        return
    }

    if isHeader {
        textStorage.addAttribute(.font, value: boldMono, range: lineRange)
    }

    // Mute pipe delimiters
    guard let pipeRegex = try? NSRegularExpression(pattern: "\\|") else { return }
    let matches = pipeRegex.matches(in: textStorage.string, range: lineRange)
    for match in matches {
        textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: match.range)
    }
}

// MARK: - Lists and Horizontal Rules

private func highlightOrderedList(_ trimmed: String, lineRange: NSRange, line: String, textStorage: NSTextStorage, palette: CatppuccinPalette) {
    guard let regex = try? NSRegularExpression(pattern: "^(\\s*)(\\d+\\.)( )") else { return }
    let nsLine = line as NSString
    let localRange = NSRange(location: 0, length: nsLine.length)
    guard let match = regex.firstMatch(in: line, range: localRange) else { return }
    let markerRange = match.range(at: 2)
    let absMarker = NSRange(location: lineRange.location + markerRange.location, length: markerRange.length)
    textStorage.addAttribute(.foregroundColor, value: palette.blue, range: absMarker)

    applyListIndent(line: line, lineRange: lineRange, textStorage: textStorage)
}

private func highlightUnorderedList(_ trimmed: String, lineRange: NSRange, line: String, textStorage: NSTextStorage, palette: CatppuccinPalette) {
    guard let regex = try? NSRegularExpression(pattern: "^(\\s*)([-*+])( )") else { return }
    let nsLine = line as NSString
    let localRange = NSRange(location: 0, length: nsLine.length)
    guard let match = regex.firstMatch(in: line, range: localRange) else { return }
    let bulletRange = match.range(at: 2)
    let absBullet = NSRange(location: lineRange.location + bulletRange.location, length: bulletRange.length)
    textStorage.addAttribute(.foregroundColor, value: palette.blue, range: absBullet)

    applyListIndent(line: line, lineRange: lineRange, textStorage: textStorage)
}

private func highlightTaskList(_ trimmed: String, lineRange: NSRange, line: String, textStorage: NSTextStorage, palette: CatppuccinPalette) {
    let checked: Bool
    if trimmed.hasPrefix("- [ ] ") || trimmed.hasPrefix("* [ ] ") || trimmed.hasPrefix("+ [ ] ") {
        checked = false
    } else if trimmed.hasPrefix("- [x] ") || trimmed.hasPrefix("* [x] ") || trimmed.hasPrefix("+ [x] ") ||
              trimmed.hasPrefix("- [X] ") || trimmed.hasPrefix("* [X] ") || trimmed.hasPrefix("+ [X] ") {
        checked = true
    } else {
        return
    }

    // Find the checkbox in the actual line
    guard let cbRegex = try? NSRegularExpression(pattern: "\\[[ xX]\\]") else { return }
    guard let cbMatch = cbRegex.firstMatch(in: textStorage.string, range: lineRange) else { return }
    let cbRange = cbMatch.range

    if checked {
        textStorage.addAttribute(.foregroundColor, value: palette.green, range: cbRange)
        let afterCb = NSRange(location: cbRange.location + cbRange.length, length: NSMaxRange(lineRange) - (cbRange.location + cbRange.length))
        if afterCb.length > 0 {
            textStorage.addAttribute(.strikethroughStyle, value: NSUnderlineStyle.single.rawValue, range: afterCb)
        }
    } else {
        textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: cbRange)
    }

    // Bullet coloring
    guard let bulletRegex = try? NSRegularExpression(pattern: "^(\\s*)([-*+])") else { return }
    let nsLine = line as NSString
    guard let bMatch = bulletRegex.firstMatch(in: line, range: NSRange(location: 0, length: nsLine.length)) else { return }
    let bulletRange = bMatch.range(at: 2)
    let absBullet = NSRange(location: lineRange.location + bulletRange.location, length: bulletRange.length)
    textStorage.addAttribute(.foregroundColor, value: palette.blue, range: absBullet)

    applyListIndent(line: line, lineRange: lineRange, textStorage: textStorage)
}

private func applyListIndent(line: String, lineRange: NSRange, textStorage: NSTextStorage) {
    let leading = line.prefix(while: { $0 == " " || $0 == "\t" })
    let spaces = leading.filter { $0 == " " }.count
    let tabs = leading.filter { $0 == "\t" }.count
    let level = tabs + spaces / 2
    if level > 0 {
        let indent = NSMutableParagraphStyle()
        let px = CGFloat(level) * 20.0
        indent.headIndent = px
        indent.firstLineHeadIndent = px
        textStorage.addAttribute(.paragraphStyle, value: indent, range: lineRange)
    }
}

private func isCordialLine(_ trimmed: String) -> Bool {
    if trimmed.isEmpty { return false }
    if trimmed.hasPrefix("/=") { return true }
    if trimmed.hasPrefix("//") { return true }
    if trimmed.hasPrefix("/*") { return true }
    if trimmed.hasPrefix("let ") {
        return trimmed.contains("=")
    }
    guard let eqIdx = trimmed.firstIndex(of: "=") else { return false }
    if eqIdx == trimmed.startIndex { return false }
    let after = trimmed.index(after: eqIdx)
    if after < trimmed.endIndex && trimmed[after] == "=" { return false }
    let before = trimmed[trimmed.index(before: eqIdx)]
    if before == "!" || before == "<" || before == ">" { return false }
    return true
}

private func isHorizontalRule(_ trimmed: String) -> Bool {
    if trimmed.isEmpty { return false }
    let stripped = trimmed.replacingOccurrences(of: " ", with: "")
    if stripped.count < 3 { return false }
    let allDash = stripped.allSatisfy { $0 == "-" }
    let allStar = stripped.allSatisfy { $0 == "*" }
    let allUnderscore = stripped.allSatisfy { $0 == "_" }
    return allDash || allStar || allUnderscore
}

private func findTableHeaderLines(textStorage: NSTextStorage, fencedRanges: [NSRange]) -> Set<Int> {
    var headerStarts = Set<Int>()
    let nsText = textStorage.string as NSString
    var lineStart = 0
    var prevLineStart: Int? = nil
    var prevTrimmed: String? = nil

    while lineStart < nsText.length {
        let lineRange = nsText.lineRange(for: NSRange(location: lineStart, length: 0))

        if !isInsideFencedBlock(lineRange, fencedRanges: fencedRanges) {
            let line = nsText.substring(with: lineRange)
            let trimmed = line.trimmingCharacters(in: .whitespacesAndNewlines)

            if trimmed.hasPrefix("|"), isTableSeparator(trimmed),
               let pStart = prevLineStart, let pTrimmed = prevTrimmed,
               pTrimmed.hasPrefix("|") {
                headerStarts.insert(pStart)
            }

            prevLineStart = lineRange.location
            prevTrimmed = trimmed
        } else {
            prevLineStart = nil
            prevTrimmed = nil
        }

        lineStart = NSMaxRange(lineRange)
    }

    return headerStarts
}

private func isTableSeparator(_ trimmed: String) -> Bool {
    guard trimmed.hasPrefix("|") else { return false }
    let inner = trimmed.trimmingCharacters(in: CharacterSet(charactersIn: "| "))
    guard !inner.isEmpty else { return false }
    let cells = inner.components(separatedBy: "|")
    return cells.allSatisfy { cell in
        let c = cell.trimmingCharacters(in: .whitespaces)
        guard let regex = try? NSRegularExpression(pattern: "^:?-{1,}:?$") else { return false }
        return regex.firstMatch(in: c, range: NSRange(location: 0, length: (c as NSString).length)) != nil
    }
}

// MARK: - Markdown Links

private func highlightLinks(textStorage: NSTextStorage, palette: CatppuccinPalette, fencedRanges: [NSRange]) {
    guard let regex = try? NSRegularExpression(pattern: "(?<!!)\\[([^\\]]+)\\]\\(([^)]+)\\)") else { return }
    let text = textStorage.string
    let fullRange = NSRange(location: 0, length: (text as NSString).length)
    let matches = regex.matches(in: text, range: fullRange)
    for match in matches {
        if isInsideFencedBlock(match.range, fencedRanges: fencedRanges) { continue }
        if isInsideInlineCode(match.range, in: textStorage) { continue }

        let openBracket = NSRange(location: match.range.location, length: 1)
        let textRange = match.range(at: 1)
        let closeBracketAndUrl = NSRange(
            location: textRange.location + textRange.length,
            length: match.range.length - textRange.length - 1
        )

        textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: openBracket)
        textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: closeBracketAndUrl)

        if textRange.length > 0 {
            let urlStr = (text as NSString).substring(with: match.range(at: 2))
            textStorage.addAttributes([
                .foregroundColor: palette.blue,
                .underlineStyle: NSUnderlineStyle.single.rawValue,
                .link: urlStr
            ], range: textRange)
        }
    }
}

// MARK: - Markdown Images

private func highlightImages(textStorage: NSTextStorage, palette: CatppuccinPalette, fencedRanges: [NSRange]) {
    guard let regex = try? NSRegularExpression(pattern: "!\\[([^\\]]*)\\]\\(([^)]+)\\)") else { return }
    let text = textStorage.string
    let fullRange = NSRange(location: 0, length: (text as NSString).length)
    let matches = regex.matches(in: text, range: fullRange)
    for match in matches {
        if isInsideFencedBlock(match.range, fencedRanges: fencedRanges) { continue }
        if isInsideInlineCode(match.range, in: textStorage) { continue }

        let bang = NSRange(location: match.range.location, length: 1)
        let openBracket = NSRange(location: match.range.location + 1, length: 1)
        let altRange = match.range(at: 1)
        let closeBracketParen = NSRange(
            location: altRange.location + altRange.length,
            length: 2
        )
        let urlRange = match.range(at: 2)
        let closeParen = NSRange(
            location: match.range.location + match.range.length - 1,
            length: 1
        )

        textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: bang)
        textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: openBracket)
        textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: closeBracketParen)
        textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: closeParen)

        if altRange.length > 0 {
            textStorage.addAttribute(.foregroundColor, value: palette.green, range: altRange)
        }
        if urlRange.length > 0 {
            textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: urlRange)
        }
    }
}

// MARK: - Autolinks

private let autolinkDetector: NSDataDetector? = {
    try? NSDataDetector(types: NSTextCheckingResult.CheckingType.link.rawValue)
}()

private func highlightAutolinks(textStorage: NSTextStorage, palette: CatppuccinPalette, fencedRanges: [NSRange]) {
    guard let detector = autolinkDetector else { return }
    let text = textStorage.string
    let fullRange = NSRange(location: 0, length: (text as NSString).length)

    let inlineCodeRanges = collectInlineCodeRanges(in: textStorage)
    let linkAttrRanges = collectLinkAttributeRanges(in: textStorage)

    let matches = detector.matches(in: text, range: fullRange)
    for match in matches {
        guard let url = match.url else { continue }
        if isInsideFencedBlock(match.range, fencedRanges: fencedRanges) { continue }
        if rangeOverlapsAny(match.range, ranges: inlineCodeRanges) { continue }
        if rangeOverlapsAny(match.range, ranges: linkAttrRanges) { continue }

        textStorage.addAttributes([
            .foregroundColor: palette.blue,
            .underlineStyle: NSUnderlineStyle.single.rawValue,
            .link: url.absoluteString
        ], range: match.range)
    }
}

private func isInsideInlineCode(_ range: NSRange, in textStorage: NSTextStorage) -> Bool {
    guard let regex = try? NSRegularExpression(pattern: "`[^`]+`") else { return false }
    let fullRange = NSRange(location: 0, length: (textStorage.string as NSString).length)
    let matches = regex.matches(in: textStorage.string, range: fullRange)
    for m in matches {
        if m.range.location <= range.location && NSMaxRange(m.range) >= NSMaxRange(range) {
            return true
        }
    }
    return false
}

private func collectInlineCodeRanges(in textStorage: NSTextStorage) -> [NSRange] {
    guard let regex = try? NSRegularExpression(pattern: "`[^`]+`") else { return [] }
    let fullRange = NSRange(location: 0, length: (textStorage.string as NSString).length)
    return regex.matches(in: textStorage.string, range: fullRange).map { $0.range }
}

private func collectLinkAttributeRanges(in textStorage: NSTextStorage) -> [NSRange] {
    var ranges: [NSRange] = []
    let fullRange = NSRange(location: 0, length: textStorage.length)
    textStorage.enumerateAttribute(.link, in: fullRange) { value, range, _ in
        if value != nil { ranges.append(range) }
    }
    return ranges
}

private func rangeOverlapsAny(_ range: NSRange, ranges: [NSRange]) -> Bool {
    for r in ranges {
        if NSIntersectionRange(range, r).length > 0 { return true }
    }
    return false
}

// MARK: - Image Cache & Path Resolution

private let imageCacheDir: URL = {
    let dir = FileManager.default.homeDirectoryForCurrentUser
        .appendingPathComponent(".swiftly/images", isDirectory: true)
    try? FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
    return dir
}()

private func resolveLocalImagePath(_ rawPath: String) -> String? {
    if rawPath.hasPrefix("http://") || rawPath.hasPrefix("https://") { return nil }
    let expanded: String
    if rawPath.hasPrefix("~/") {
        expanded = (rawPath as NSString).expandingTildeInPath
    } else if rawPath.hasPrefix("/") {
        expanded = rawPath
    } else if rawPath.hasPrefix("file://") {
        expanded = URL(string: rawPath)?.path ?? rawPath
    } else {
        expanded = rawPath
    }
    return expanded
}

// MARK: - LineNumberTextView

class LineNumberTextView: NSTextView {
    static let gutterWidth: CGFloat = 50
    var evalResults: [Int: String] = [:]

    override var textContainerOrigin: NSPoint {
        return NSPoint(x: LineNumberTextView.gutterWidth, y: textContainerInset.height)
    }

    override func setFrameSize(_ newSize: NSSize) {
        super.setFrameSize(newSize)
        let insetWidth = textContainerInset.width
        textContainer?.size.width = newSize.width - LineNumberTextView.gutterWidth - insetWidth
    }

    override func drawInsertionPoint(in rect: NSRect, color: NSColor, turnedOn flag: Bool) {
        var widened = rect
        widened.size.width = 2
        super.drawInsertionPoint(in: widened, color: color, turnedOn: flag)
    }

    override func drawBackground(in rect: NSRect) {
        super.drawBackground(in: rect)

        let origin = textContainerOrigin
        let gutterRect = NSRect(x: 0, y: rect.origin.y, width: LineNumberTextView.gutterWidth, height: rect.height)
        Theme.current.mantle.setFill()
        gutterRect.fill()

        drawLineNumbers(origin: origin)
    }

    private func drawLineNumbers(origin: NSPoint) {
        guard let lm = layoutManager, let tc = textContainer else { return }
        let palette = Theme.current
        let text = string as NSString
        guard text.length > 0 else { return }

        let lineMode = UserDefaults.standard.string(forKey: "lineIndicatorMode") ?? "on"

        var containerVisible = visibleRect
        containerVisible.origin.x -= origin.x
        containerVisible.origin.y -= origin.y
        let visibleGlyphs = lm.glyphRange(forBoundingRect: containerVisible, in: tc)
        let visibleChars = lm.characterRange(forGlyphRange: visibleGlyphs, actualGlyphRange: nil)

        var lineNumber = 1
        var idx = 0
        while idx < visibleChars.location {
            if text.character(at: idx) == 0x0A { lineNumber += 1 }
            idx += 1
        }

        var cursorLine = 1
        if lineMode == "vim" {
            let cursorPos = selectedRange().location
            var ci = 0
            while ci < min(cursorPos, text.length) {
                if text.character(at: ci) == 0x0A { cursorLine += 1 }
                ci += 1
            }
        }

        let lineAttrs: [NSAttributedString.Key: Any] = [
            .font: Theme.gutterFont,
            .foregroundColor: palette.overlay0
        ]
        let currentLineAttrs: [NSAttributedString.Key: Any] = [
            .font: Theme.gutterFont,
            .foregroundColor: palette.text
        ]
        let resultAttrs: [NSAttributedString.Key: Any] = [
            .font: Theme.gutterFont,
            .foregroundColor: palette.teal
        ]

        var charIndex = visibleChars.location
        while charIndex < NSMaxRange(visibleChars) {
            let lineRange = text.lineRange(for: NSRange(location: charIndex, length: 0))
            let lineGlyphRange = lm.glyphRange(forCharacterRange: lineRange, actualCharacterRange: nil)
            let lineRect = lm.boundingRect(forGlyphRange: lineGlyphRange, in: tc)
            let y = lineRect.origin.y + origin.y

            if lineMode != "off" {
                let displayNum: Int
                let attrs: [NSAttributedString.Key: Any]
                if lineMode == "vim" {
                    if lineNumber == cursorLine {
                        displayNum = lineNumber
                        attrs = currentLineAttrs
                    } else {
                        displayNum = abs(lineNumber - cursorLine)
                        attrs = lineAttrs
                    }
                } else {
                    displayNum = lineNumber
                    attrs = lineAttrs
                }
                let numStr = NSAttributedString(string: "\(displayNum)", attributes: attrs)
                let numSize = numStr.size()
                numStr.draw(at: NSPoint(x: LineNumberTextView.gutterWidth - numSize.width - 8, y: y))
            }

            if let result = evalResults[lineNumber - 1] {
                let resultStr = NSAttributedString(string: "\u{2192} \(result)", attributes: resultAttrs)
                let size = resultStr.size()
                let rightEdge = visibleRect.maxX
                resultStr.draw(at: NSPoint(x: rightEdge - size.width - 8, y: y))
            }

            lineNumber += 1
            charIndex = NSMaxRange(lineRange)
        }
    }

    // MARK: - Paste (image from clipboard)

    override func paste(_ sender: Any?) {
        let pb = NSPasteboard.general
        let imageTypes: [NSPasteboard.PasteboardType] = [.tiff, .png]

        if let imageType = imageTypes.first(where: { pb.data(forType: $0) != nil }),
           let data = pb.data(forType: imageType) {
            if let image = NSImage(data: data), let pngData = image.tiffRepresentation,
               let bitmap = NSBitmapImageRep(data: pngData),
               let png = bitmap.representation(using: .png, properties: [:]) {
                let uuid = UUID().uuidString
                let path = imageCacheDir.appendingPathComponent("\(uuid).png")
                do {
                    try png.write(to: path)
                    let markdown = "![image](~/.swiftly/images/\(uuid).png)"
                    insertText(markdown, replacementRange: selectedRange())
                    return
                } catch {}
            }
        }
        super.paste(sender)
    }

    // MARK: - Drag and Drop

    override func draggingEntered(_ sender: NSDraggingInfo) -> NSDragOperation {
        if sender.draggingPasteboard.canReadObject(forClasses: [NSURL.self], options: [
            .urlReadingFileURLsOnly: true
        ]) {
            return .copy
        }
        return super.draggingEntered(sender)
    }

    override func performDragOperation(_ sender: NSDraggingInfo) -> Bool {
        guard let urls = sender.draggingPasteboard.readObjects(forClasses: [NSURL.self], options: [
            .urlReadingFileURLsOnly: true
        ]) as? [URL] else {
            return super.performDragOperation(sender)
        }

        let imageExts: Set<String> = ["png", "jpg", "jpeg", "gif", "bmp", "tiff", "webp"]
        guard let ts = textStorage else { return false }

        var didInsert = false
        for url in urls {
            let ext = url.pathExtension.lowercased()
            if imageExts.contains(ext) {
                let uuid = UUID().uuidString
                let dest = imageCacheDir.appendingPathComponent("\(uuid).\(ext)")
                let markdown: String
                do {
                    try FileManager.default.copyItem(at: url, to: dest)
                    markdown = "![image](~/.swiftly/images/\(uuid).\(ext))"
                } catch {
                    markdown = "![\(url.lastPathComponent)](\(url.path))"
                }
                insertText(markdown, replacementRange: selectedRange())
                didInsert = true
            } else {
                let attachment = NSTextAttachment()
                let cell = FileEmbedCell(filePath: url.path)
                attachment.attachmentCell = cell
                let attachStr = NSMutableAttributedString(string: "\n")
                attachStr.append(NSAttributedString(attachment: attachment))
                let insertAt = min(selectedRange().location, ts.length)
                ts.insert(attachStr, at: insertAt)
                didInsert = true
            }
        }

        return didInsert || super.performDragOperation(sender)
    }
}