// backend\serve_video.go

package main

import (
	"bytes"
	"context"
	"fmt"
	"math"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"time"
)

func serveVideoFile(w http.ResponseWriter, r *http.Request, path string) {
	f, err := openForReadShareDelete(path)
	if err != nil {
		http.Error(w, "datei öffnen fehlgeschlagen: "+err.Error(), http.StatusInternalServerError)
		return
	}
	defer f.Close()

	fi, err := f.Stat()
	if err != nil || fi.IsDir() || fi.Size() == 0 {
		http.Error(w, "datei nicht gefunden", http.StatusNotFound)
		return
	}

	w.Header().Set("Cache-Control", "no-store")
	w.Header().Set("Accept-Ranges", "bytes")
	w.Header().Set("X-Content-Type-Options", "nosniff")

	ext := strings.ToLower(filepath.Ext(path))
	switch ext {
	case ".ts":
		w.Header().Set("Content-Type", "video/mp2t")
	default:
		w.Header().Set("Content-Type", "video/mp4")
	}

	// ServeContent unterstützt Range Requests (wichtig für Video)
	http.ServeContent(w, r, filepath.Base(path), fi.ModTime(), f)
}

func sniffVideoKind(path string) (string, error) {
	f, err := openForReadShareDelete(path)
	if err != nil {
		return "", err
	}
	defer f.Close()

	buf := make([]byte, 64)
	n, _ := f.Read(buf)
	buf = buf[:n]

	// HTML?
	trim := bytes.TrimSpace(buf)
	if len(trim) >= 1 && trim[0] == '<' {
		return "html", nil
	}

	// MPEG-TS: 0x47 sync byte
	if len(buf) >= 1 && buf[0] == 0x47 {
		return "ts", nil
	}

	// MP4: "ftyp" typischerweise bei Offset 4
	if len(buf) >= 8 && string(buf[4:8]) == "ftyp" {
		return "mp4", nil
	}

	return "unknown", nil
}

func maybeRemuxTS(path string) (string, error) {
	path = strings.TrimSpace(path)
	if path == "" {
		return "", nil
	}

	if !strings.EqualFold(filepath.Ext(path), ".ts") {
		return "", nil
	}

	mp4 := strings.TrimSuffix(path, filepath.Ext(path)) + ".mp4"

	// remux (ohne neu encoden)
	if err := remuxTSToMP4(path, mp4); err != nil {
		return "", err
	}

	_ = os.Remove(path) // TS entfernen, wenn MP4 ok
	return mp4, nil
}

func maybeRemuxTSForJob(job *RecordJob, path string) (string, error) {
	path = strings.TrimSpace(path)
	if path == "" {
		return "", nil
	}

	if !strings.EqualFold(filepath.Ext(path), ".ts") {
		return "", nil
	}

	mp4 := strings.TrimSuffix(path, filepath.Ext(path)) + ".mp4"

	// input size für fallback (optional für progress/ffmpeg)
	var inSize int64
	if fi, err := os.Stat(path); err == nil && fi != nil && !fi.IsDir() {
		inSize = fi.Size()
	}

	// duration (für sauberen progress)
	var durSec float64
	{
		durCtx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
		durSec, _ = durationSecondsCached(durCtx, path)
		cancel()
	}

	// Throttle + monoton (lokal), globale Monotonie macht setJobProgress
	lastProgress := -1
	lastTick := time.Now().Add(-time.Second)

	onRatio := func(r float64) {
		if r < 0 {
			r = 0
		}
		if r > 1 {
			r = 1
		}

		p := int(math.Round(r * 100))
		if p < 0 {
			p = 0
		}
		if p > 100 {
			p = 100
		}

		// nur steigen lassen
		if p <= lastProgress {
			return
		}

		// leicht throttlen (außer kurz vor Schluss)
		if time.Since(lastTick) < 150*time.Millisecond && p < 99 {
			return
		}

		lastProgress = p
		lastTick = time.Now()

		// ✅ wichtig: 0..100 übergeben (Mapping macht setJobProgress)
		setJobProgress(job, "remuxing", p)
	}

	remuxCtx, cancel := context.WithTimeout(context.Background(), 30*time.Minute)
	defer cancel()

	if err := remuxTSToMP4WithProgress(remuxCtx, path, mp4, durSec, inSize, onRatio); err != nil {
		return "", err
	}

	_ = os.Remove(path) // TS entfernen, wenn MP4 ok

	// ✅ Remux finished
	setJobProgress(job, "remuxing", 100)

	return mp4, nil
}

func moveToDoneDir(src string) (string, error) {
	src = strings.TrimSpace(src)
	if src == "" {
		return "", fmt.Errorf("src empty")
	}

	s := getSettings()

	doneAbs, err := resolvePathRelativeToApp(s.DoneDir)
	if err != nil || strings.TrimSpace(doneAbs) == "" {
		// fallback
		doneAbs = strings.TrimSpace(s.DoneDir)
	}
	if strings.TrimSpace(doneAbs) == "" {
		return "", fmt.Errorf("doneDir empty")
	}

	// Quelle normalisieren/abs machen (best effort)
	srcAbs := filepath.Clean(src)
	if !filepath.IsAbs(srcAbs) {
		if abs, rerr := resolvePathRelativeToApp(srcAbs); rerr == nil && strings.TrimSpace(abs) != "" {
			srcAbs = abs
		}
	}

	fi, err := os.Stat(srcAbs)
	if err != nil || fi.IsDir() {
		return "", fmt.Errorf("src not found: %v", err)
	}

	file := filepath.Base(srcAbs)

	// Zielordner: immer done/ (keine model-subdirs)
	dstDir := doneAbs

	if err := os.MkdirAll(dstDir, 0o755); err != nil {
		return "", err
	}

	// Bei Kollisionen eindeutigen Namen wählen
	dst, err := uniqueDestPath(dstDir, file)
	if err != nil {
		return "", err
	}

	// Robust verschieben (Windows / Locks / Cross-device)
	if err := renameWithRetry(srcAbs, dst); err != nil {
		return "", err
	}

	// Duration-Cache invalidieren (du nutzt das ja)
	purgeDurationCacheForPath(srcAbs)

	return dst, nil
}