package itemimage

import (
	"bytes"
	"image"
	"image/color"
	"image/png"
	"strings"
	"testing"

	"printer.backend/internal/model"
)

const sampleItemSVG = `<?xml version="1.0" encoding="UTF-8"?>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="-13 -13 106 106">
  <defs>
    <clipPath id="item-mask">
      <rect x="0" y="0" width="80" height="80" rx="5" ry="5" />
    </clipPath>
  </defs>
  <g clip-path="url(#item-mask)">
    <rect x="-2" y="-2" width="84" height="84" fill="#00FF00" opacity="0.7" />
  </g>
</svg>`

func testPNG(w, h int) []byte {
	img := image.NewRGBA(image.Rect(0, 0, w, h))
	for y := 0; y < h; y++ {
		for x := 0; x < w; x++ {
			img.Set(x, y, color.RGBA{uint8(x % 256), uint8(y % 256), 128, 255})
		}
	}
	var buf bytes.Buffer
	_ = png.Encode(&buf, img)
	return buf.Bytes()
}

func TestEmbedReplacesGreenMask(t *testing.T) {
	spec := model.ItemSpec{WidthMM: 80, HeightMM: 80, BleedMM: 2, MarginMM: 5, PaddingMM: 3}
	out, err := Embed([]byte(sampleItemSVG), spec, testPNG(1, 1), "image/png")
	if err != nil {
		t.Fatal(err)
	}
	s := string(out)
	if strings.Contains(s, "#00FF00") || strings.Contains(s, "#00ff00") {
		t.Fatal("green placeholder should be replaced")
	}
	if !strings.Contains(s, `<image `) || !strings.Contains(s, `preserveAspectRatio="xMidYMid slice"`) {
		t.Fatalf("expected embedded image, got: %s", s)
	}
	if !strings.Contains(s, `x="-2.0000"`) {
		t.Fatal("expected bleed-aligned image placement")
	}
	if !strings.Contains(s, "data:image/jpeg;base64,") {
		t.Fatal("expected downscaled jpeg data uri")
	}
}

func TestEmbedDownscalesLargeImage(t *testing.T) {
	spec := model.ItemSpec{WidthMM: 80, HeightMM: 80, BleedMM: 2, MarginMM: 5, PaddingMM: 3}
	huge := testPNG(4000, 3000)
	out, err := Embed([]byte(sampleItemSVG), spec, huge, "image/png")
	if err != nil {
		t.Fatal(err)
	}
	const maxSVG = 600_000 // ~600 KB embedded payload is plenty for rsvg
	if len(out) > maxSVG {
		t.Fatalf("embedded svg too large: %d bytes", len(out))
	}
}

func TestEmbedInvalidSVG(t *testing.T) {
	spec := model.ItemSpec{WidthMM: 80, HeightMM: 80, BleedMM: 2, MarginMM: 5}
	_, err := Embed([]byte("<svg></svg>"), spec, testPNG(1, 1), "image/png")
	if err == nil {
		t.Fatal("expected error")
	}
}