package main

import (
	"bytes"
	"encoding/base64"
	"image"
	"image/color"
	"image/jpeg"
	"image/png"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

func writeTestImage(t *testing.T, name string, w, h int, asJPEG bool) string {
	t.Helper()
	img := image.NewRGBA(image.Rect(0, 0, w, h))
	for x := 0; x < w; x += 3 {
		for y := 0; y < h; y += 3 {
			img.Set(x, y, color.RGBA{R: uint8(x % 255), G: uint8(y % 255), B: 128, A: 255})
		}
	}
	var buf bytes.Buffer
	var e error
	if asJPEG {
		e = jpeg.Encode(&buf, img, nil)
	} else {
		e = png.Encode(&buf, img)
	}
	if e != nil {
		t.Fatal(e)
	}
	p := filepath.Join(t.TempDir(), name)
	if e := os.WriteFile(p, buf.Bytes(), 0o644); e != nil {
		t.Fatal(e)
	}
	return p
}

func decodeDataURL(t *testing.T, dataURL string) image.Image {
	t.Helper()
	i := strings.Index(dataURL, ";base64,")
	if !strings.HasPrefix(dataURL, "data:image/") || i < 0 {
		t.Fatalf("not a data URL: %.40s", dataURL)
	}
	raw, e := base64.StdEncoding.DecodeString(dataURL[i+8:])
	if e != nil {
		t.Fatal(e)
	}
	img, _, e := image.Decode(bytes.NewReader(raw))
	if e != nil {
		t.Fatal(e)
	}
	return img
}

func TestImageFileToDataURLDownscalesLargeImages(t *testing.T) {
	p := writeTestImage(t, "big.png", 600, 400, false)
	dataURL, e := imageFileToDataURL(p)
	if e != nil {
		t.Fatal(e)
	}
	if !strings.HasPrefix(dataURL, "data:image/png;base64,") {
		t.Fatalf("png source should stay png: %.40s", dataURL)
	}
	img := decodeDataURL(t, dataURL)
	if b := img.Bounds(); b.Dx() != 256 || b.Dy() != 170 {
		t.Fatalf("expected 256x170, got %dx%d", b.Dx(), b.Dy())
	}
}

func TestImageFileToDataURLKeepsSmallJPEG(t *testing.T) {
	p := writeTestImage(t, "small.jpg", 120, 80, true)
	dataURL, e := imageFileToDataURL(p)
	if e != nil {
		t.Fatal(e)
	}
	if !strings.HasPrefix(dataURL, "data:image/jpeg;base64,") {
		t.Fatalf("jpeg source should stay jpeg: %.40s", dataURL)
	}
	img := decodeDataURL(t, dataURL)
	if b := img.Bounds(); b.Dx() != 120 || b.Dy() != 80 {
		t.Fatalf("small image should keep size, got %dx%d", b.Dx(), b.Dy())
	}
}

func TestImageFileToDataURLErrors(t *testing.T) {
	if _, e := imageFileToDataURL(filepath.Join(t.TempDir(), "missing.png")); e == nil || e.Error() != "FILE_NOT_FOUND" {
		t.Fatalf("want FILE_NOT_FOUND, got %v", e)
	}
	bad := filepath.Join(t.TempDir(), "not-image.png")
	if e := os.WriteFile(bad, []byte("hello world"), 0o644); e != nil {
		t.Fatal(e)
	}
	if _, e := imageFileToDataURL(bad); e == nil || e.Error() != "AVATAR_DECODE_FAILED" {
		t.Fatalf("want AVATAR_DECODE_FAILED, got %v", e)
	}
}

func TestEnsureDefaultAvatar(t *testing.T) {
	s, e := OpenStore(filepath.Join(t.TempDir(), "defavatar.db"))
	if e != nil {
		t.Fatal(e)
	}
	defer s.db.Close()
	a := &App{store: s}
	a.ensureDefaultAvatar()
	st, e := s.Settings()
	if e != nil {
		t.Fatal(e)
	}
	if st.AvatarMode != "base64" || !strings.HasPrefix(st.AvatarValue, "data:image/") {
		t.Fatalf("default avatar not set: mode=%q value=%.40s", st.AvatarMode, st.AvatarValue)
	}
	if s.Meta("avatar_updated_at") == "" {
		t.Fatal("default avatar should bump avatar_updated_at so sync pushes it")
	}
	if img := decodeDataURL(t, st.AvatarValue); img.Bounds().Dx() > avatarMaxEdge || img.Bounds().Dy() > avatarMaxEdge {
		t.Fatalf("default avatar should fit %dpx, got %v", avatarMaxEdge, img.Bounds())
	}
	// 已设置过头像时不覆盖。
	st.AvatarMode, st.AvatarValue = "url", "https://cdn.example.com/me.png"
	if e = s.SaveSettings(st); e != nil {
		t.Fatal(e)
	}
	a.ensureDefaultAvatar()
	got, e := s.Settings()
	if e != nil {
		t.Fatal(e)
	}
	if got.AvatarMode != "url" || got.AvatarValue != "https://cdn.example.com/me.png" {
		t.Fatalf("existing avatar should not be overwritten: mode=%q", got.AvatarMode)
	}
}

func TestSaveSettingsBumpsAvatarTimestampOnlyOnAvatarChange(t *testing.T) {
	s, e := OpenStore(filepath.Join(t.TempDir(), "avatar.db"))
	if e != nil {
		t.Fatal(e)
	}
	defer s.db.Close()
	base, e := s.Settings()
	if e != nil {
		t.Fatal(e)
	}
	base.Theme = "light"
	if e = s.SaveSettings(base); e != nil {
		t.Fatal(e)
	}
	if got := s.Meta("avatar_updated_at"); got != "" {
		t.Fatalf("non-avatar save should not bump avatar timestamp, got %q", got)
	}
	base.AvatarMode, base.AvatarValue = "url", "https://cdn.example.com/a.png"
	if e = s.SaveSettings(base); e != nil {
		t.Fatal(e)
	}
	first := s.Meta("avatar_updated_at")
	if first == "" {
		t.Fatal("avatar change should bump timestamp")
	}
	got, e := s.Settings()
	if e != nil {
		t.Fatal(e)
	}
	if got.AvatarMode != "url" || got.AvatarValue != "https://cdn.example.com/a.png" {
		t.Fatalf("avatar not persisted: %+v", got)
	}
	// 非法模式会被清空存储。
	base.AvatarMode, base.AvatarValue = "weird", "x"
	if e = s.SaveSettings(base); e != nil {
		t.Fatal(e)
	}
	got, _ = s.Settings()
	if got.AvatarMode != "" || got.AvatarValue != "" {
		t.Fatalf("invalid mode should clear avatar, got %+v", got)
	}
}