package main

import (
	"fmt"
	"math"
	"os"
)

func WriteSCAD(filename string, triangles [][3]Point) error {
	// Fallback/legacy mesh WriteSCAD
	f, err := os.Create(filename)
	if err != nil {
		return err
	}
	defer f.Close()

	fmt.Fprintf(f, "// Generated by pcb-to-stencil\npolyhedron(\n  points=[\n")
	for i, t := range triangles {
		fmt.Fprintf(f, "    [%f, %f, %f], [%f, %f, %f], [%f, %f, %f]", t[0].X, t[0].Y, t[0].Z, t[1].X, t[1].Y, t[1].Z, t[2].X, t[2].Y, t[2].Z)
		if i < len(triangles)-1 {
			fmt.Fprintf(f, ",\n")
		} else {
			fmt.Fprintf(f, "\n")
		}
	}
	fmt.Fprintf(f, "  ],\n  faces=[\n")
	for i := 0; i < len(triangles); i++ {
		idx := i * 3
		fmt.Fprintf(f, "    [%d, %d, %d]", idx, idx+1, idx+2)
		if i < len(triangles)-1 {
			fmt.Fprintf(f, ",\n")
		} else {
			fmt.Fprintf(f, "\n")
		}
	}
	fmt.Fprintf(f, "  ]\n);\n")
	return nil
}

// ExtractPolygonFromGerber traces the Edge.Cuts gerber to form a continuous 2D polygon
func ExtractPolygonFromGerber(gf *GerberFile) [][2]float64 {
	var points [][2]float64
	curX, curY := 0.0, 0.0
	interpolationMode := "G01"

	for _, cmd := range gf.Commands {
		if cmd.Type == "G01" || cmd.Type == "G02" || cmd.Type == "G03" {
			interpolationMode = cmd.Type
			continue
		}

		prevX, prevY := curX, curY
		if cmd.X != nil {
			curX = *cmd.X
		}
		if cmd.Y != nil {
			curY = *cmd.Y
		}

		if cmd.Type == "DRAW" {
			if len(points) == 0 {
				points = append(points, [2]float64{prevX, prevY})
			}

			if interpolationMode == "G01" {
				points = append(points, [2]float64{curX, curY})
			} else {
				iVal, jVal := 0.0, 0.0
				if cmd.I != nil {
					iVal = *cmd.I
				}
				if cmd.J != nil {
					jVal = *cmd.J
				}
				centerX, centerY := prevX+iVal, prevY+jVal
				radius := math.Sqrt(iVal*iVal + jVal*jVal)
				startAngle := math.Atan2(prevY-centerY, prevX-centerX)
				endAngle := math.Atan2(curY-centerY, curX-centerX)
				if interpolationMode == "G03" {
					if endAngle <= startAngle {
						endAngle += 2 * math.Pi
					}
				} else {
					if startAngle <= endAngle {
						startAngle += 2 * math.Pi
					}
				}
				arcLen := math.Abs(endAngle-startAngle) * radius
				steps := int(arcLen * 10)
				if steps < 5 {
					steps = 5
				}
				for s := 1; s <= steps; s++ {
					t := float64(s) / float64(steps)
					a := startAngle + t*(endAngle-startAngle)
					ax, ay := centerX+radius*math.Cos(a), centerY+radius*math.Sin(a)
					points = append(points, [2]float64{ax, ay})
				}
			}
		}
	}
	return points
}

// WriteNativeSCAD generates native parametrically defined CSG OpenSCAD code
func WriteNativeSCAD(filename string, isTray bool, outlineVertices [][2]float64, cfg EnclosureConfig, holes []DrillHole, cutouts []SideCutout, minBX, maxBX, boardCenterY float64) error {
	f, err := os.Create(filename)
	if err != nil {
		return err
	}
	defer f.Close()

	fmt.Fprintf(f, "// Generated by pcb-to-stencil (Native SCAD)\n")
	fmt.Fprintf(f, "$fn = 60;\n\n")

	// 1. Output the Board Polygon Module
	fmt.Fprintf(f, "module board_polygon() {\n  polygon(points=[\n")
	for i, v := range outlineVertices {
		fmt.Fprintf(f, "    [%f, %f]", v[0], v[1])
		if i < len(outlineVertices)-1 {
			fmt.Fprintf(f, ",\n")
		}
	}
	fmt.Fprintf(f, "\n  ]);\n}\n\n")

	// Dimensions
	clearance := cfg.Clearance
	wt := cfg.WallThickness
	lidThick := wt
	snapHeight := 2.5
	trayFloor := 1.5
	pcbT := cfg.PCBThickness
	totalH := cfg.WallHeight + pcbT + trayFloor
	lipH := pcbT + 1.5

	// Create Peg and Socket helper
	fmt.Fprintf(f, "module mounting_pegs(isSocket) {\n")
	for _, h := range holes {
		if h.Type == DrillTypeMounting {
			r := (h.Diameter / 2.0) - 0.15
			if isTray {
				// We subtract sockets from the tray floor
				r = (h.Diameter / 2.0) + 0.1
				fmt.Fprintf(f, "  translate([%f, %f, -1]) cylinder(r=%f, h=%f);\n", h.X, h.Y, r, trayFloor+2)
			} else {
				fmt.Fprintf(f, "  translate([%f, %f, 0]) cylinder(r=%f, h=%f);\n", h.X, h.Y, r, totalH-lidThick)
			}
		}
	}
	fmt.Fprintf(f, "}\n\n")

	// Print Side Cutouts module
	fmt.Fprintf(f, "module side_cutouts() {\n")
	for _, c := range cutouts {
		// Cutouts are relative to board.
		x, y, z := 0.0, 0.0, c.Height/2+trayFloor+pcbT
		w, d, h := c.Width, 20.0, c.Height // d is deep enough to cut through walls
		if c.Side == 0 {                   // Top
			y = outlineVertices[0][1] + 10 // rough outside pos
			x = c.X
			fmt.Fprintf(f, "  translate([%f, %f, %f]) cube([%f, %f, %f], center=true);\n", x, y, z, w, d, h)
		} else if c.Side == 1 { // Right
			x = maxBX
			y = c.Y
			fmt.Fprintf(f, "  translate([%f, %f, %f]) cube([%f, %f, %f], center=true);\n", x, y, z, d, w, h)
		} else if c.Side == 2 { // Bottom
			y = outlineVertices[0][1] - 10
			x = c.X
			fmt.Fprintf(f, "  translate([%f, %f, %f]) cube([%f, %f, %f], center=true);\n", x, y, z, w, d, h)
		} else if c.Side == 3 { // Left
			x = minBX
			y = c.Y
			fmt.Fprintf(f, "  translate([%f, %f, %f]) cube([%f, %f, %f], center=true);\n", x, y, z, d, w, h)
		}
	}
	fmt.Fprintf(f, "}\n\n")

	// Print Pry Slots Module
	fmt.Fprintf(f, "module pry_slots() {\n")
	pryW := 8.0
	pryD := 1.5
	fmt.Fprintf(f, "  translate([%f, %f, 0]) cube([%f, %f, %f], center=true);\n", minBX-clearance-wt+pryD/2, boardCenterY, pryD*2, pryW, snapHeight*3)
	fmt.Fprintf(f, "  translate([%f, %f, 0]) cube([%f, %f, %f], center=true);\n", maxBX+clearance+wt-pryD/2, boardCenterY, pryD*2, pryW, snapHeight*3)
	fmt.Fprintf(f, "}\n\n")

	if isTray {
		// --- TRAY ---
		fmt.Fprintf(f, "// --- TRAY ---\n")
		fmt.Fprintf(f, "difference() {\n")
		fmt.Fprintf(f, "  union() {\n")
		fmt.Fprintf(f, "    // Tray Floor (extends to clearance + 2*wt so it is flush with enclosure outside)\n")
		fmt.Fprintf(f, "    linear_extrude(height=%f) offset(r=%f) board_polygon();\n", trayFloor, clearance+2*wt)
		fmt.Fprintf(f, "    // Tray Inner Wall (thickness wt)\n")
		fmt.Fprintf(f, "    translate([0,0,%f]) linear_extrude(height=%f) difference() {\n", trayFloor, snapHeight)
		fmt.Fprintf(f, "      offset(r=%f) board_polygon();\n", clearance+wt)
		fmt.Fprintf(f, "      offset(r=%f) board_polygon();\n", clearance)
		fmt.Fprintf(f, "    }\n")
		fmt.Fprintf(f, "    // Snap Bumps (on outside of tray wall)\n")
		fmt.Fprintf(f, "    translate([0,0,%f]) linear_extrude(height=%f) difference() {\n", trayFloor+snapHeight-0.6, 0.4)
		fmt.Fprintf(f, "      offset(r=%f) board_polygon();\n", clearance+wt+0.4)
		fmt.Fprintf(f, "      offset(r=%f) board_polygon();\n", clearance+wt)
		fmt.Fprintf(f, "    }\n")
		fmt.Fprintf(f, "    // Mounting Pegs\n")
		for _, hole := range holes {
			if hole.Type != DrillTypeMounting {
				continue
			}
			pegRadius := (hole.Diameter / 2.0) - 0.15
			fmt.Fprintf(f, "    translate([%f,%f,0]) cylinder(h=%f, r=%f, $fn=32);\n", hole.X, hole.Y, totalH-lidThick, pegRadius)
		}
		fmt.Fprintf(f, "  }\n")

		fmt.Fprintf(f, "  // Subtract Lip Recess (for easy opening)\n")
		fmt.Fprintf(f, "  translate([0,0,-1]) linear_extrude(height=%f) difference() {\n", trayFloor+lipH+0.5)
		fmt.Fprintf(f, "    offset(r=%f) board_polygon();\n", clearance+2*wt+1.0)
		fmt.Fprintf(f, "    offset(r=%f) board_polygon();\n", clearance+2*wt-0.5) // Assuming lipCut is 0.5mm
		fmt.Fprintf(f, "  }\n")

		// Remove peg holes from floor
		for _, hole := range holes {
			if hole.Type != DrillTypeMounting {
				continue
			}
			socketRadius := (hole.Diameter / 2.0) + 0.1
			fmt.Fprintf(f, "  translate([%f,%f,-1]) cylinder(h=%f, r=%f, $fn=32);\n", hole.X, hole.Y, trayFloor+2, socketRadius)
		}
		fmt.Fprintf(f, "  pry_slots();\n")
		fmt.Fprintf(f, "  side_cutouts();\n")
		fmt.Fprintf(f, "}\n\n")

	} else {
		// --- ENCLOSURE ---
		fmt.Fprintf(f, "// --- ENCLOSURE ---\n")
		fmt.Fprintf(f, "difference() {\n")
		fmt.Fprintf(f, "  union() {\n")
		fmt.Fprintf(f, "    // Outer Enclosure block (accommodates Tray Wall + Enclosure Wall)\n")
		fmt.Fprintf(f, "    translate([0,0,%f]) linear_extrude(height=%f) offset(r=%f) board_polygon();\n", trayFloor, totalH-trayFloor, clearance+2*wt)
		fmt.Fprintf(f, "  }\n")
		fmt.Fprintf(f, "  // Subtract Inner Cavity (Base clearance around board)\n")
		fmt.Fprintf(f, "  translate([0,0,-1]) linear_extrude(height=%f) offset(r=%f) board_polygon();\n", totalH-lidThick+1, clearance)
		fmt.Fprintf(f, "  // Subtract Tray Recess (Accommodates Tray Wall)\n")
		fmt.Fprintf(f, "  translate([0,0,-1]) linear_extrude(height=%f) offset(r=%f) board_polygon();\n", trayFloor+snapHeight+0.2, clearance+wt+0.15)

		fmt.Fprintf(f, "  // Subtract Snap Groove\n")
		fmt.Fprintf(f, "  translate([0,0,%f]) linear_extrude(height=%f) difference() {\n", trayFloor+snapHeight-0.7, 0.6)
		fmt.Fprintf(f, "    offset(r=%f) board_polygon();\n", clearance+wt+0.5)
		fmt.Fprintf(f, "    offset(r=%f) board_polygon();\n", clearance+wt)
		fmt.Fprintf(f, "  }\n")
		fmt.Fprintf(f, "  pry_slots();\n")
		fmt.Fprintf(f, "  side_cutouts();\n")
		fmt.Fprintf(f, "}\n")
		fmt.Fprintf(f, "mounting_pegs(false);\n")
	}

	return nil
}