//go:build cgo

package transform_test

import (
	"image"
	"image/color"
	"image/jpeg"
	"bytes"
	"testing"

	"atp.pics/internal/transform"
)

func makeJPEG(w, h int) []byte {
	img := image.NewRGBA(image.Rect(0, 0, w, h))
	for y := range h {
		for x := range w {
			img.Set(x, y, color.RGBA{R: 100, G: 150, B: 200, A: 255})
		}
	}
	var buf bytes.Buffer
	_ = jpeg.Encode(&buf, img, &jpeg.Options{Quality: 90})
	return buf.Bytes()
}

func TestTransform_ProportionalResize_WidthOnly(t *testing.T) {
	src := makeJPEG(400, 200)
	out, ct, err := transform.Transform(src, "image/jpeg", transform.Params{Width: 200, Format: "webp"})
	if err != nil {
		t.Fatalf("Transform error: %v", err)
	}
	if ct != "image/webp" {
		t.Errorf("Content-Type = %q, want image/webp", ct)
	}
	if len(out) == 0 {
		t.Error("output is empty")
	}
}

func TestTransform_ProportionalResize_HeightOnly(t *testing.T) {
	src := makeJPEG(400, 200)
	out, ct, err := transform.Transform(src, "image/jpeg", transform.Params{Height: 100, Format: "webp"})
	if err != nil {
		t.Fatalf("Transform error: %v", err)
	}
	if ct != "image/webp" {
		t.Errorf("Content-Type = %q, want image/webp", ct)
	}
	if len(out) == 0 {
		t.Error("output is empty")
	}
}

func TestTransform_CoverFit_BothDimensions(t *testing.T) {
	src := makeJPEG(400, 200)
	out, ct, err := transform.Transform(src, "image/jpeg", transform.Params{Width: 100, Height: 100, Format: "webp"})
	if err != nil {
		t.Fatalf("Transform error: %v", err)
	}
	if ct != "image/webp" {
		t.Errorf("Content-Type = %q, want image/webp", ct)
	}
	if len(out) == 0 {
		t.Error("output is empty")
	}
}

func TestTransform_JPEG_Output(t *testing.T) {
	src := makeJPEG(200, 200)
	out, ct, err := transform.Transform(src, "image/jpeg", transform.Params{Width: 100, Height: 100, Quality: 80, Format: "jpg"})
	if err != nil {
		t.Fatalf("Transform error: %v", err)
	}
	if ct != "image/jpeg" {
		t.Errorf("Content-Type = %q, want image/jpeg", ct)
	}
	if len(out) == 0 {
		t.Error("output is empty")
	}
}

func TestTransform_PNG_Output(t *testing.T) {
	src := makeJPEG(200, 200)
	out, ct, err := transform.Transform(src, "image/jpeg", transform.Params{Width: 100, Height: 100, Format: "png"})
	if err != nil {
		t.Fatalf("Transform error: %v", err)
	}
	if ct != "image/png" {
		t.Errorf("Content-Type = %q, want image/png", ct)
	}
	if len(out) == 0 {
		t.Error("output is empty")
	}
}

func TestTransform_NoResize_DefaultDimensions(t *testing.T) {
	src := makeJPEG(300, 150)
	out, ct, err := transform.Transform(src, "image/jpeg", transform.Params{Format: "webp", Quality: 85})
	if err != nil {
		t.Fatalf("Transform error: %v", err)
	}
	if ct != "image/webp" {
		t.Errorf("Content-Type = %q, want image/webp", ct)
	}
	if len(out) == 0 {
		t.Error("output is empty")
	}
}