package player

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"github.com/lwoodard/rtsp-streamer/internal/config"
	"github.com/lwoodard/rtsp-streamer/internal/logbuf"
)

func TestLastLinePrefersRealMessageOverStatus(t *testing.T) {
	w := logbuf.New(20)
	fmt.Fprintln(w, "Failed to open rtsps://host/x: Connection refused")
	fmt.Fprint(w, "\x1b[KV: 00:00:35 / 00:00:35 (100%)\n") // ANSI-wrapped status
	if got := lastLine(w); got != "Failed to open rtsps://host/x: Connection refused" {
		t.Errorf("lastLine = %q, want the error line", got)
	}
}

func TestLastLineFallsBackToStatusWhenOnlyStatus(t *testing.T) {
	w := logbuf.New(20)
	fmt.Fprint(w, "\x1b[KV: 00:00:20 / 00:00:20 (100%)\n")
	if got := lastLine(w); got != "V: 00:00:20 / 00:00:20 (100%)" {
		t.Errorf("lastLine = %q, want the stripped status line", got)
	}
}

func TestLastLineNil(t *testing.T) {
	if got := lastLine(nil); got != "" {
		t.Errorf("lastLine(nil) = %q, want empty", got)
	}
}

func testClock(cfg config.Clock) *Clock {
	return &Clock{cfg: cfg, textPath: "/run/user/1000/rtsp-streamer/clock-text.txt"}
}

// A zero-alpha canvas makes the drawn text inherit alpha 0, so the clock
// renders as nothing at all. Config clamps the opacity, and args() must clamp
// too rather than emitting a fully transparent canvas.
func TestClockCanvasIsNeverFullyTransparent(t *testing.T) {
	for _, opacity := range []float64{0, -1, 0.45, 1} {
		c := testClock(config.Clock{Width: 300, Height: 72, BackgroundOpacity: opacity})
		src := c.args()[len(c.args())-1]
		if strings.Contains(src, "black@0.000") {
			t.Errorf("opacity %v produced a fully transparent canvas: %s", opacity, src)
		}
		if !strings.Contains(src, "s=300x72") {
			t.Errorf("opacity %v: size missing from %s", opacity, src)
		}
	}
}

// The configured opacity must reach the filtergraph verbatim.
func TestClockCanvasUsesConfiguredOpacity(t *testing.T) {
	src := testClock(config.Clock{Width: 300, Height: 72, BackgroundOpacity: 0.6}).args()
	if got := src[len(src)-1]; !strings.Contains(got, "black@0.600") {
		t.Errorf("got %s, want canvas alpha 0.600", got)
	}
}

// The time must be baked into every frame by drawtext, reloading the text file
// each frame. An mpv OSD overlay only renders on the frame where its content
// changes, which showed up as a flashing clock.
func TestClockDrawsTextIntoEveryFrame(t *testing.T) {
	c := testClock(config.Clock{Width: 300, Height: 72, FontSize: 44})
	src := c.args()[len(c.args())-1]
	for _, want := range []string{
		"drawtext=textfile=" + c.textPath,
		"reload=1",    // re-read the file per frame, else the clock freezes
		"fontsize=44", // from config, not hardcoded
		"borderw=3",   // outline for legibility over bright scenes
	} {
		if !strings.Contains(src, want) {
			t.Errorf("filtergraph missing %q:\n  %s", want, src)
		}
	}
}

// drawtext stamps the time when a frame is generated, so buffering ahead makes
// the visible clock lag. These flags keep generation just-in-time.
func TestClockDisablesReadahead(t *testing.T) {
	args := testClock(config.Clock{Width: 300, Height: 72, FontSize: 44}).args()
	joined := strings.Join(args, " ")
	for _, want := range []string{"--cache=no", "--demuxer-readahead-secs=0"} {
		if !strings.Contains(joined, want) {
			t.Errorf("args missing %q", want)
		}
	}
}

// writeText must replace the file atomically so drawtext cannot read a
// half-written time, and must honour the configured layout and zone.
func TestClockWriteTextIsAtomicAndFormatted(t *testing.T) {
	dir := t.TempDir()
	loc, err := time.LoadLocation("America/Denver")
	if err != nil {
		t.Fatal(err)
	}
	c := &Clock{
		cfg:      config.Clock{Format: "15:04:05"},
		loc:      loc,
		textPath: filepath.Join(dir, "clock-text.txt"),
	}
	if err := c.writeText(); err != nil {
		t.Fatal(err)
	}
	b, err := os.ReadFile(c.textPath)
	if err != nil {
		t.Fatal(err)
	}
	if got := string(b); len(got) != len("15:04:05") {
		t.Errorf("wrote %q, want an HH:MM:SS-shaped time", got)
	}
	// The temp file used for the atomic rename must not be left behind.
	if _, err := os.Stat(c.textPath + ".tmp"); !os.IsNotExist(err) {
		t.Errorf("temp file left behind: %v", err)
	}
}