package webp_test

import (
	"bytes"
	"errors"
	"image"
	"image/color"
	"image/draw"
	"io"
	"strings"
	"testing"

	"git.golem15.com/golem15/summercms/modules/lagoon/attach"
	"git.golem15.com/golem15/summercms/modules/lagoon/attach/webp"
	"gocloud.dev/blob/memblob"
)

// TestEncodeImageKinds pins Encode on the image kinds a decoder hands it:
// RGBA, NRGBA, grey, paletted and YCbCr pictures all come out as a WebP of
// the same size, and a 1x1 picture too.
func TestEncodeImageKinds(t *testing.T) {
	rgba := gradient(48, 30)
	nrgba := image.NewNRGBA(rgba.Bounds())
	draw.Draw(nrgba, nrgba.Bounds(), rgba, image.Point{}, draw.Src)
	gray := image.NewGray(rgba.Bounds())
	draw.Draw(gray, gray.Bounds(), rgba, image.Point{}, draw.Src)
	pal := image.NewPaletted(rgba.Bounds(), color.Palette{color.Black, color.White, color.RGBA{200, 20, 20, 255}})
	draw.Draw(pal, pal.Bounds(), rgba, image.Point{}, draw.Src)
	ycc := image.NewYCbCr(rgba.Bounds(), image.YCbCrSubsampleRatio420)
	one := image.NewRGBA(image.Rect(0, 0, 1, 1))
	for name, img := range map[string]image.Image{"rgba": rgba, "nrgba": nrgba, "gray": gray, "paletted": pal, "ycbcr": ycc, "1x1": one} {
		var buf bytes.Buffer
		if err := webp.Encode(&buf, img); err != nil {
			t.Fatalf("%s: %v", name, err)
		}
		cfg, format, err := image.DecodeConfig(bytes.NewReader(buf.Bytes()))
		b := img.Bounds()
		if err != nil || format != "webp" || cfg.Width != b.Dx() || cfg.Height != b.Dy() || !isWebP(buf.Bytes()) {
			t.Fatalf("%s: decoded %+v %q err=%v, want a %dx%d webp", name, cfg, format, err, b.Dx(), b.Dy())
		}
	}
}

// TestEncodeConstants pins the variant's format, content type and quality.
func TestEncodeConstants(t *testing.T) {
	if webp.Format != "webp" || webp.ContentType != "image/webp" || webp.Quality < 1 || webp.Quality > 100 {
		t.Fatalf("Format %q ContentType %q Quality %d", webp.Format, webp.ContentType, webp.Quality)
	}
}

// TestVariantStoredWithContentType pins the stored variant's content type
// and that the variant key is the thumbnail's VariantKey, and that a
// second call answers the same key without touching the stored bytes.
func TestVariantStoredWithContentType(t *testing.T) {
	bucket := memblob.OpenBucket(nil)
	defer bucket.Close()
	f := &attach.File{ID: 11, DiskName: "jkl012mno345pqr678stu9.jpg"}
	putOriginal(t, bucket, f, 320, 200)
	key, err := webp.Variant(t.Context(), bucket, f, 160, 100, "exact")
	if err != nil {
		t.Fatal(err)
	}
	thumb, err := f.ThumbKey(t.Context(), bucket, 160, 100, "exact")
	if err != nil || key != attach.VariantKey(thumb, webp.Format) {
		t.Fatalf("key %q, thumbnail %q err=%v", key, thumb, err)
	}
	attrs, err := bucket.Attributes(t.Context(), key)
	if err != nil || attrs.ContentType != webp.ContentType {
		t.Fatalf("attributes %+v err=%v, want image/webp", attrs, err)
	}
	before, _ := bucket.ReadAll(t.Context(), key)
	again, err := webp.Variant(t.Context(), bucket, f, 160, 100, "exact")
	after, _ := bucket.ReadAll(t.Context(), key)
	if err != nil || again != key || !bytes.Equal(before, after) {
		t.Fatalf("second call %q err=%v, bytes changed %v", again, err, !bytes.Equal(before, after))
	}
}

// TestVariantBrokenAndRefused pins the edges: a missing original gets
// ThumbKey's broken-image thumbnail, whose variant is still a WebP; a mode
// outside the token rule is refused and writes no variant.
func TestVariantBrokenAndRefused(t *testing.T) {
	bucket := memblob.OpenBucket(nil)
	defer bucket.Close()
	missing := &attach.File{ID: 12, DiskName: "vwx901yza234bcd567efg8.jpg"}
	key, err := webp.Variant(t.Context(), bucket, missing, 100, 100, "exact")
	if err != nil {
		t.Fatal(err)
	}
	if raw, err := bucket.ReadAll(t.Context(), key); err != nil || !isWebP(raw) {
		t.Fatalf("variant of the broken-image thumbnail %q: err=%v", key, err)
	}
	good := &attach.File{ID: 14, DiskName: "tuv345wxy678zab901cde2.jpg"}
	putOriginal(t, bucket, good, 200, 200)
	if _, err := webp.Variant(t.Context(), bucket, good, 100, 100, "../x"); err == nil {
		t.Fatal("a mode outside the token rule must fail")
	}
	iter := bucket.List(nil)
	webps := 0
	for {
		obj, err := iter.Next(t.Context())
		if errors.Is(err, io.EOF) {
			break
		}
		if err != nil {
			t.Fatal(err)
		}
		if strings.HasSuffix(obj.Key, ".webp") {
			webps++
		}
	}
	if webps != 1 {
		t.Fatalf("%d WebP files in the bucket, want only the broken-image variant", webps)
	}
}