package main

import (
	"fmt"
	"io"
	"os"
	"path/filepath"
	"strings"
)

type VWStencilConfigJS struct {
	Clearance     float64 `json:"clearance"`
	WallThickness float64 `json:"wallThickness"`
	TranslateX    float64 `json:"translateX"`
	TranslateY    float64 `json:"translateY"`
	Rotation      float64 `json:"rotation"`
	ScaleX        float64 `json:"scaleX"`
	ScaleY        float64 `json:"scaleY"`
}

type VWStencilResultJS struct {
	SCADSource string `json:"scadSource"`
	SCADPath   string `json:"scadPath"`
}

// GenerateVectorWrapStencil creates a SCAD file: thin shell conforming to the
// object surface with the SVG vector art cut through as stencil openings.
func (a *App) GenerateVectorWrapStencil(cfg VWStencilConfigJS) (*VWStencilResultJS, error) {
	a.mu.RLock()
	vws := a.vectorWrapSession
	projPath := a.projectPath
	a.mu.RUnlock()

	if vws == nil {
		return nil, fmt.Errorf("no vector wrap session active")
	}
	if vws.SVGPath == "" {
		return nil, fmt.Errorf("no SVG loaded for vector wrap")
	}

	debugLog("GenerateVectorWrapStencil: svg=%s model=%s (%s)", vws.SVGPath, vws.ModelPath, vws.ModelType)

	if cfg.Clearance <= 0 {
		cfg.Clearance = 0.2
	}
	if cfg.WallThickness <= 0 {
		cfg.WallThickness = 0.8
	}
	if cfg.ScaleX == 0 {
		cfg.ScaleX = 1
	}
	if cfg.ScaleY == 0 {
		cfg.ScaleY = 1
	}

	outDir := formerTempDir()
	if projPath != "" {
		outDir = filepath.Join(projPath, "output")
	}
	os.MkdirAll(outDir, 0755)

	// Copy SVG to output directory so the SCAD can reference it
	svgDest := filepath.Join(outDir, "stencil_art.svg")
	if err := copyFile(vws.SVGPath, svgDest); err != nil {
		return nil, fmt.Errorf("copy SVG: %w", err)
	}

	// Determine object source
	objectSCAD, sourceType, err := a.resolveObjectSource(vws)
	if err != nil {
		return nil, err
	}

	// If STL, copy it to output dir too
	stlRef := ""
	if sourceType == "stl" {
		stlDest := filepath.Join(outDir, "stencil_model.stl")
		if err := os.WriteFile(stlDest, vws.ModelSTL, 0644); err != nil {
			return nil, fmt.Errorf("write STL: %w", err)
		}
		stlRef = "stencil_model.stl"
	}

	// Get SVG dimensions
	svgW, svgH := 100.0, 100.0
	if vws.SVGDoc != nil {
		svgW = vws.SVGDoc.Width
		svgH = vws.SVGDoc.Height
	}

	scad := buildVWStencilSCAD(objectSCAD, sourceType, stlRef, svgW, svgH, cfg)

	scadPath := filepath.Join(outDir, "wrap_stencil.scad")
	if err := os.WriteFile(scadPath, []byte(scad), 0644); err != nil {
		return nil, fmt.Errorf("write SCAD: %w", err)
	}

	debugLog("GenerateVectorWrapStencil: wrote %s (%d bytes)", scadPath, len(scad))

	return &VWStencilResultJS{
		SCADSource: scad,
		SCADPath:   scadPath,
	}, nil
}

func (a *App) resolveObjectSource(vws *VectorWrapSession) (string, string, error) {
	// SCAD source
	if vws.ModelType == "scad" && vws.ModelPath != "" {
		data, err := os.ReadFile(vws.ModelPath)
		if err != nil {
			return "", "", fmt.Errorf("read SCAD model: %w", err)
		}
		return string(data), "scad", nil
	}

	// STL
	if vws.ModelType == "stl" && len(vws.ModelSTL) > 0 {
		return "", "stl", nil
	}

	// Project object — check for reconstructed.scad
	a.mu.RLock()
	projPath := a.projectPath
	a.mu.RUnlock()
	if projPath != "" {
		scadPath := filepath.Join(projPath, "output", "reconstructed.scad")
		if data, err := os.ReadFile(scadPath); err == nil && len(data) > 10 {
			return string(data), "scad", nil
		}
	}

	// Reconstructed STL in vectorwrap dir
	if vws.ModelPath != "" && len(vws.ModelSTL) > 0 {
		return "", "stl", nil
	}

	return "", "", fmt.Errorf("no object source found")
}

func buildVWStencilSCAD(objectSCAD, sourceType, stlRef string, svgW, svgH float64, cfg VWStencilConfigJS) string {
	cl := cfg.Clearance
	wt := cfg.WallThickness

	var buf strings.Builder
	buf.WriteString("// Vector Wrap Stencil — fits around the object for painting/marking\n")
	buf.WriteString(fmt.Sprintf("// Shell: clearance=%.2fmm, wall=%.2fmm\n\n", cl, wt))
	buf.WriteString("$fn = 32;\n\n")

	// Target object module
	buf.WriteString("module target() {\n")
	if sourceType == "stl" {
		buf.WriteString(fmt.Sprintf("    import(%q);\n", stlRef))
	} else {
		for _, line := range strings.Split(objectSCAD, "\n") {
			buf.WriteString("    " + line + "\n")
		}
	}
	buf.WriteString("}\n\n")

	// Shell module
	buf.WriteString("module shell() {\n")
	buf.WriteString("    difference() {\n")
	buf.WriteString(fmt.Sprintf("        minkowski() { target(); sphere(r=%.4f); }\n", cl+wt))
	buf.WriteString(fmt.Sprintf("        minkowski() { target(); sphere(r=%.4f); }\n", cl))
	buf.WriteString("    }\n")
	buf.WriteString("}\n\n")

	// SVG art module with user transforms
	buf.WriteString("module art() {\n")
	buf.WriteString(fmt.Sprintf("    translate([%.4f, %.4f, 0])\n", cfg.TranslateX, cfg.TranslateY))
	buf.WriteString(fmt.Sprintf("    rotate([0, 0, %.4f])\n", cfg.Rotation))
	buf.WriteString(fmt.Sprintf("    scale([%.4f, %.4f, 1])\n", cfg.ScaleX, cfg.ScaleY))
	// Center the SVG around origin
	buf.WriteString(fmt.Sprintf("    translate([%.4f, %.4f, 0])\n", -svgW/2, -svgH/2))
	buf.WriteString("        import(\"stencil_art.svg\");\n")
	buf.WriteString("}\n\n")

	// Stencil: shell minus SVG projected from all 6 cardinal directions
	buf.WriteString("// Stencil: shell with SVG art cut through from all directions\n")
	buf.WriteString("difference() {\n")
	buf.WriteString("    shell();\n\n")

	// Project from Z+ (top-down)
	buf.WriteString("    // Top-down projection\n")
	buf.WriteString("    linear_extrude(height=500, center=true)\n")
	buf.WriteString("        art();\n\n")

	// Project from Z- (bottom-up) — same as top-down for extrude center=true
	// Already covered by center=true

	// Project from X+ (right side)
	buf.WriteString("    // Right side projection\n")
	buf.WriteString("    rotate([90, 0, 90])\n")
	buf.WriteString("        linear_extrude(height=500, center=true)\n")
	buf.WriteString("            art();\n\n")

	// Project from Y+ (front)
	buf.WriteString("    // Front projection\n")
	buf.WriteString("    rotate([90, 0, 0])\n")
	buf.WriteString("        linear_extrude(height=500, center=true)\n")
	buf.WriteString("            art();\n")

	buf.WriteString("}\n")

	return buf.String()
}

func copyFile(src, dst string) error {
	in, err := os.Open(src)
	if err != nil {
		return err
	}
	defer in.Close()

	out, err := os.Create(dst)
	if err != nil {
		return err
	}
	defer out.Close()

	_, err = io.Copy(out, in)
	return err
}