package ui

import (
	"bytes"
	"context"
	"encoding/base64"
	"image"
	"image/color"
	"image/gif"
	"image/jpeg"
	"image/png"
	"strings"
	"sync/atomic"
	"testing"
	"time"

	"github.com/gdamore/tcell/v2"
)

// stripes returns a w×h image whose top half is red and bottom half blue.
func stripes(w, h int) *image.RGBA {
	img := image.NewRGBA(image.Rect(0, 0, w, h))
	for y := 0; y < h; y++ {
		for x := 0; x < w; x++ {
			c := color.RGBA{255, 0, 0, 255}
			if y >= h/2 {
				c = color.RGBA{0, 0, 255, 255}
			}
			img.SetRGBA(x, y, c)
		}
	}
	return img
}

func TestBoxScaleAverages(t *testing.T) {
	src := image.NewRGBA(image.Rect(0, 0, 2, 2))
	src.SetRGBA(0, 0, color.RGBA{200, 0, 0, 255})
	src.SetRGBA(1, 0, color.RGBA{0, 0, 0, 255})
	src.SetRGBA(0, 1, color.RGBA{0, 0, 0, 255})
	src.SetRGBA(1, 1, color.RGBA{0, 0, 0, 255})
	got := boxScale(src, 1, 1).RGBAAt(0, 0)
	if got.R < 49 || got.R > 51 || got.G != 0 || got.A != 255 {
		t.Errorf("average = %+v, want R≈50", got)
	}
	// Upscaling must not leave holes.
	up := boxScale(stripes(1, 2), 3, 4)
	if up.RGBAAt(2, 0).R != 255 || up.RGBAAt(2, 3).B != 255 {
		t.Errorf("upscaled corners: %+v %+v", up.RGBAAt(2, 0), up.RGBAAt(2, 3))
	}
}

func TestDecodeCover(t *testing.T) {
	var buf bytes.Buffer
	if err := jpeg.Encode(&buf, stripes(300, 450), nil); err != nil {
		t.Fatal(err)
	}
	img, err := decodeCover(buf.Bytes(), storedCoverHeight)
	if err != nil {
		t.Fatal(err)
	}
	if b := img.Bounds(); b.Dy() != storedCoverHeight || b.Dx() != 106 {
		t.Errorf("stored size %v, want 106x%d", b, storedCoverHeight)
	}

	buf.Reset()
	if err := png.Encode(&buf, stripes(20, 30)); err != nil {
		t.Fatal(err)
	}
	if img, err := decodeCover(buf.Bytes(), storedCoverHeight); err != nil || img.Bounds().Dy() != 30 {
		t.Errorf("small png kept as is: %v %v", img, err)
	}

	if _, err := decodeCover([]byte("<html>not an image</html>"), storedCoverHeight); err == nil {
		t.Error("garbage must be rejected")
	}
	// A header that promises a huge image is refused before decoding it.
	var huge bytes.Buffer
	huge.Write([]byte("\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR\x00\x00\x27\x10\x00\x00\x27\x10\x08\x02\x00\x00\x00"))
	if _, err := decodeCover(huge.Bytes(), storedCoverHeight); err == nil {
		t.Error("oversized image must be rejected")
	}
}

func TestQuadCell(t *testing.T) {
	red, blue, black := color.RGBA{255, 0, 0, 255}, color.RGBA{0, 0, 255, 255}, color.RGBA{0, 0, 0, 255}
	for _, tc := range []struct {
		name     string
		px       [4]color.RGBA
		wantCh   rune
		wantFg   color.RGBA
		wantBg   color.RGBA
		sameBoth bool
	}{
		{"flat", [4]color.RGBA{red, red, red, red}, ' ', red, red, true},
		{"top half", [4]color.RGBA{red, red, blue, blue}, '▀', red, blue, false},
		{"bottom half", [4]color.RGBA{blue, blue, red, red}, '▀', blue, red, false}, // same picture, canonical form
		{"left half", [4]color.RGBA{red, blue, red, blue}, '▌', red, blue, false},
		{"one corner", [4]color.RGBA{red, blue, blue, blue}, '▘', red, blue, false},
		{"diagonal", [4]color.RGBA{red, black, black, red}, '▞', black, red, false},
	} {
		ch, fg, bg := quadrantStyle.bestCell(tc.px[:])
		if ch != tc.wantCh || fg != tc.wantFg || bg != tc.wantBg {
			t.Errorf("%s: %q fg=%v bg=%v, want %q fg=%v bg=%v", tc.name, ch, fg, bg, tc.wantCh, tc.wantFg, tc.wantBg)
		}
	}
	// Nearly flat noise stays a flat cell instead of a distracting pattern.
	n := color.RGBA{100, 100, 100, 255}
	m := color.RGBA{102, 100, 101, 255}
	if ch, _, _ := quadrantStyle.bestCell([]color.RGBA{n, m, n, n}); ch != ' ' {
		t.Errorf("noise rendered as %q", ch)
	}
}

func TestCoverCells(t *testing.T) {
	// A 2:3 poster in a roomy box is limited by the height: 10 rows are 20
	// width units tall, so 13 columns.
	if c, r := coverCells(40, 60, 30, 10, 2); c != 13 || r != 10 {
		t.Errorf("tall limit: %dx%d", c, r)
	}
	// In a narrow box the width limits it, and the box keeps the poster's shape
	// (8×6 cells is exactly 2:3) instead of 10×7 which would leave bars.
	if c, r := coverCells(40, 60, 10, 20, 2); c != 8 || r != 6 {
		t.Errorf("narrow limit: %dx%d", c, r)
	}
}

func TestCoverViewDraws(t *testing.T) {
	screen := tcell.NewSimulationScreen("")
	if err := screen.Init(); err != nil {
		t.Fatal(err)
	}
	defer screen.Fini()
	screen.SetSize(30, 10)

	c := newCoverView(quadrantStyle, nil, nil)
	c.setImage(stripes(40, 60)) // red above blue
	c.SetRect(0, 0, 30, 10)     // fits 13 columns × 10 rows

	c.Draw(screen)
	rgba := func(c tcell.Color) color.RGBA {
		r, g, b := c.RGB()
		return color.RGBA{uint8(r), uint8(g), uint8(b), 255}
	}
	cell := func(x, y int) (rune, color.RGBA, color.RGBA) {
		ch, _, st, _ := screen.GetContent(x, y)
		fg, bg, _ := st.Decompose()
		return ch, rgba(fg), rgba(bg)
	}
	red, blue := color.RGBA{255, 0, 0, 255}, color.RGBA{0, 0, 255, 255}
	// The poster is 13 columns wide and sits against the right edge (x 17..29).
	if _, fg, bg := cell(17, 0); fg != red || bg != red {
		t.Errorf("top row = fg %v bg %v, want red", fg, bg)
	}
	if _, fg, bg := cell(29, 9); fg != blue || bg != blue {
		t.Errorf("bottom right = fg %v bg %v, want blue", fg, bg)
	}
	// Left of the poster's footprint nothing is drawn.
	if ch, _, _, _ := screen.GetContent(16, 0); ch != ' ' {
		t.Errorf("poster stretched beyond its aspect ratio: %q", ch)
	}
}

func TestLoadCoverCachesAndDedupes(t *testing.T) {
	a := newTestApp(t)
	var fetches atomic.Int32
	var buf bytes.Buffer
	png.Encode(&buf, stripes(10, 20))
	ref := coverRef{key: "k", fetch: func(context.Context) ([]byte, error) {
		fetches.Add(1)
		return buf.Bytes(), nil
	}}

	// Run posted callbacks inline instead of through the (not running) event loop.
	delivered := make(chan error, 2)
	a.loadCover(ref, func(_ *image.RGBA, err error) { delivered <- err })
	a.loadCover(ref, func(_ *image.RGBA, err error) { delivered <- err }) // joins the request in flight
	if len(a.coverCache.waiting["k"]) != 2 {
		t.Fatalf("waiters = %d, want 2", len(a.coverCache.waiting["k"]))
	}
	if n := fetches.Load(); n > 1 {
		t.Errorf("fetched %d times", n)
	}
}

func TestLoadCoverRemembersFailures(t *testing.T) {
	a := newTestApp(t)
	a.coverCache.failed["bad"] = time.Now()
	var gotErr error
	a.loadCover(coverRef{key: "bad", fetch: func(context.Context) ([]byte, error) {
		t.Error("a recent failure must not be retried")
		return nil, nil
	}}, func(_ *image.RGBA, err error) { gotErr = err })
	if gotErr == nil {
		t.Error("expected an error for a recently failed cover")
	}
}

func TestSextantGlyphs(t *testing.T) {
	seen := map[rune]int{}
	for mask := 0; mask < 64; mask++ {
		r := sextantGlyph(mask)
		if prev, dup := seen[r]; dup {
			t.Fatalf("masks %d and %d share the glyph %q", prev, mask, r)
		}
		seen[r] = mask
		if mask > 0 && mask < 63 && mask != 21 && mask != 42 && (r < 0x1FB00 || r > 0x1FB3B) {
			t.Errorf("mask %d: %U outside the sextant block", mask, r)
		}
	}
	for mask, want := range map[int]rune{1: 0x1FB00, 2: 0x1FB01, 20: 0x1FB13, 22: 0x1FB14, 43: 0x1FB28, 62: 0x1FB3B, 21: '▌', 42: '▐', 63: '█', 0: ' '} {
		if got := sextantGlyph(mask); got != want {
			t.Errorf("sextantGlyph(%d) = %U, want %U", mask, got, want)
		}
	}
}

func TestSextantCell(t *testing.T) {
	red, blue := color.RGBA{255, 0, 0, 255}, color.RGBA{0, 0, 255, 255}
	// Two rows of red above one row of blue.
	ch, fg, bg := sextantStyle.bestCell([]color.RGBA{red, red, red, red, blue, blue})
	if ch != sextantGlyph(15) || fg != red || bg != blue {
		t.Errorf("got %U fg=%v bg=%v", ch, fg, bg)
	}
	// One row each: red, blue, red.
	ch, fg, bg = sextantStyle.bestCell([]color.RGBA{red, red, blue, blue, red, red})
	if ch != sextantGlyph(0b001100) || fg != blue || bg != red {
		t.Errorf("three bands: %U fg=%v bg=%v", ch, fg, bg)
	}
}

func TestCoverStyleForFontCheck(t *testing.T) {
	defer func(old func() bool) { sextantFontAvailable = old }(sextantFontAvailable)
	env := func(m map[string]string) func(string) string { return func(k string) string { return m[k] } }

	sextantFontAvailable = func() bool { return true }
	for _, tc := range []struct {
		name string
		env  map[string]string
		want string
	}{
		{"unknown terminal with a suitable font", map[string]string{"TERM": "xterm-256color"}, "sextant"},
		{"over ssh the local fonts are unknown", map[string]string{"TERM": "xterm-256color", "SSH_CONNECTION": "1 2 3 4"}, "quadrant"},
		{"over ssh with a tty", map[string]string{"SSH_TTY": "/dev/pts/1"}, "quadrant"},
	} {
		if got := coverStyleFor("auto", env(tc.env)).name; got != tc.want {
			t.Errorf("%s: %s, want %s", tc.name, got, tc.want)
		}
	}
	// An explicit setting never asks fontconfig.
	sextantFontAvailable = func() bool { t.Error("fontconfig consulted for an explicit style"); return true }
	if coverStyleFor("quadrant", env(nil)).name != "quadrant" || coverStyleFor("sextant", env(nil)).name != "sextant" {
		t.Error("explicit styles must win")
	}
	// No suitable font: quadrants.
	sextantFontAvailable = func() bool { return false }
	if got := coverStyleFor("auto", env(map[string]string{"TERM": "xterm-256color"})).name; got != "quadrant" {
		t.Errorf("no font: %s", got)
	}
}

func TestCoverStyleFor(t *testing.T) {
	defer func(old func() bool) { sextantFontAvailable = old }(sextantFontAvailable)
	sextantFontAvailable = func() bool { return false } // the table below is about the terminal checks
	env := func(m map[string]string) func(string) string { return func(k string) string { return m[k] } }
	for _, tc := range []struct {
		setting string
		env     map[string]string
		want    string
	}{
		{"auto", map[string]string{"TERM": "xterm-kitty"}, "sextant"},
		{"", map[string]string{"TERM_PROGRAM": "WezTerm"}, "sextant"},
		{"auto", map[string]string{"TERM": "foot"}, "sextant"},
		{"auto", map[string]string{"KITTY_WINDOW_ID": "3", "TERM": "screen"}, "sextant"},
		{"auto", map[string]string{"TERM": "xterm-256color"}, "quadrant"},
		{"auto", nil, "quadrant"},
		{"quadrant", map[string]string{"TERM": "xterm-kitty"}, "quadrant"},
		{"sextant", nil, "sextant"},
	} {
		if got := coverStyleFor(tc.setting, env(tc.env)).name; got != tc.want {
			t.Errorf("%q %v = %s, want %s", tc.setting, tc.env, got, tc.want)
		}
	}
}

func TestCoverCellsKeepTheShape(t *testing.T) {
	// For many poster shapes, cell shapes and boxes the chosen box must match
	// the poster within the tolerance (or be the closest available).
	for _, img := range [][2]int{{167, 250}, {500, 750}, {2, 3}, {1000, 1500}, {680, 1000}} {
		for _, aspect := range []float64{1.9, 2, 2.1, 2.25} {
			for w := 12; w <= 40; w += 7 {
				for h := 8; h <= 30; h += 11 {
					c, r := coverCells(img[0], img[1], w, h, aspect)
					if c < 1 || r < 1 || c > w || r > h {
						t.Fatalf("%v aspect %v in %dx%d: %dx%d out of bounds", img, aspect, w, h, c, r)
					}
					shape := float64(img[0]) / float64(img[1])
					err := float64(c)/(float64(r)*aspect)/shape - 1
					if err < 0 {
						err = -err
					}
					if err > 0.10 { // the tolerance is 3%; tiny boxes may only get within a cell
						t.Errorf("%v aspect %v in %dx%d: box %dx%d is %.0f%% off", img, aspect, w, h, c, r, err*100)
					}
				}
			}
		}
	}
}

func TestDecodeCoverOtherFormats(t *testing.T) {
	// A WebP stored under a .jpg name, as Sonarr keeps what the provider sends.
	webp, _ := base64.StdEncoding.DecodeString("UklGRhoAAABXRUJQVlA4TA0AAAAvAAAAEAcQERGIiP4HAA==")
	img, err := decodeCover(webp, storedCoverHeight)
	if err != nil || img.Bounds().Dx() != 1 || img.Bounds().Dy() != 1 {
		t.Fatalf("webp: %v %v", img, err)
	}

	var buf bytes.Buffer
	pal := image.NewPaletted(image.Rect(0, 0, 20, 30), []color.Color{color.RGBA{255, 0, 0, 255}, color.RGBA{0, 0, 255, 255}})
	if err := gif.Encode(&buf, pal, nil); err != nil {
		t.Fatal(err)
	}
	if img, err := decodeCover(buf.Bytes(), storedCoverHeight); err != nil || img.Bounds().Dy() != 30 {
		t.Errorf("gif: %v %v", img, err)
	}
}

func TestDescribeBytesAndTheErrorItGives(t *testing.T) {
	for _, tc := range []struct {
		name string
		data []byte
		want string
	}{
		{"empty", nil, "empty"},
		{"avif", []byte("\x00\x00\x00\x1cftypavif\x00\x00"), "AVIF/HEIC, avif"},
		{"html", []byte("  <html><body>Not Found</body></html>"), "HTML or SVG"},
		{"bmp", []byte("BM\x00\x00\x00\x00"), "BMP"},
		{"tiff", []byte("II*\x00\x08\x00"), "TIFF"},
		{"binary", []byte{1, 2, 3, 4, 5}, "5 bytes starting 01 02 03 04 05"},
	} {
		if got := describeBytes(tc.data); !strings.Contains(got, tc.want) {
			t.Errorf("%s: %q, want it to mention %q", tc.name, got, tc.want)
		}
		_, err := decodeCover(tc.data, storedCoverHeight)
		if err == nil || !strings.Contains(err.Error(), tc.want) {
			t.Errorf("%s: the error %v should say what the data is (%q)", tc.name, err, tc.want)
		}
	}
}