// backend\assets_generate.go

package main

import (
	"context"
	"fmt"
	"os"
	"path/filepath"
	"strings"
	"time"
)

func formatBytesSI(b int64) string {
	if b < 0 {
		b = 0
	}
	const unit = 1024
	if b < unit {
		return fmt.Sprintf("%d B", b)
	}
	div, exp := int64(unit), 0
	for n := b / unit; n >= unit; n /= unit {
		div *= unit
		exp++
	}
	suffix := []string{"KB", "MB", "GB", "TB", "PB"}
	v := float64(b) / float64(div)
	// 1 Nachkommastelle, außer sehr große ganze Zahlen
	if v >= 10 {
		return fmt.Sprintf("%.0f %s", v, suffix[exp])
	}
	return fmt.Sprintf("%.1f %s", v, suffix[exp])
}

func u64ToI64(x uint64) int64 {
	if x > uint64(maxInt64) {
		return maxInt64
	}
	return int64(x)
}

func ensureAssetsForVideo(videoPath string) error {
	// Default: keine SourceURL (für Covers egal)
	return ensureAssetsForVideoWithProgress(videoPath, "", nil)
}

// Optional: für Stellen, wo du die URL hast (z.B. Postwork / Jobs)
func ensureAssetsForVideoWithSource(videoPath string, sourceURL string) error {
	return ensureAssetsForVideoWithProgress(videoPath, sourceURL, nil)
}

// onRatio: 0..1 (Assets-Gesamtfortschritt)
func ensureAssetsForVideoWithProgress(videoPath string, sourceURL string, onRatio func(r float64)) error {
	videoPath = strings.TrimSpace(videoPath)
	if videoPath == "" {
		return nil
	}

	fi, statErr := os.Stat(videoPath)
	if statErr != nil || fi.IsDir() || fi.Size() <= 0 {
		return nil
	}

	// ✅ ID = Dateiname ohne Endung (immer OHNE "HOT " Prefix)
	base := filepath.Base(videoPath)
	id := strings.TrimSuffix(base, filepath.Ext(base))
	id = stripHotPrefix(id)
	if strings.TrimSpace(id) == "" {
		return nil
	}

	assetDir, gerr := ensureGeneratedDir(id)
	if gerr != nil || strings.TrimSpace(assetDir) == "" {
		return fmt.Errorf("generated dir: %v", gerr)
	}

	metaPath := filepath.Join(assetDir, "meta.json")

	// ---- Meta / Duration + Props (Width/Height/FPS/Resolution) ----
	durSec := 0.0
	vw, vh := 0, 0
	fps := 0.0

	// 1) Try cache (Meta) first (inkl. w/h/fps)
	if d, mw, mh, mfps, ok := readVideoMeta(metaPath, fi); ok {
		durSec, vw, vh, fps = d, mw, mh, mfps
	} else {
		// 2) Duration berechnen
		dctx, cancel := context.WithTimeout(context.Background(), 6*time.Second)
		d, derr := durationSecondsCached(dctx, videoPath)
		cancel()

		if derr == nil && d > 0 {
			durSec = d
		}
	}

	// 3) Wenn wir Duration haben, aber Props fehlen -> ffprobe holen und Voll-Meta schreiben
	//    (damit resolution wirklich in meta.json landet)
	if durSec > 0 && (vw <= 0 || vh <= 0 || fps <= 0) {
		pctx, cancel := context.WithTimeout(context.Background(), 8*time.Second)
		defer cancel()

		// optional: durSem für ffprobe begrenzen (du hast es global)
		if durSem != nil {
			if err := durSem.Acquire(pctx); err == nil {
				vw, vh, fps, _ = probeVideoProps(pctx, videoPath)
				durSem.Release()
			} else {
				// wenn Acquire fehlschlägt, best-effort ohne props
			}
		} else {
			vw, vh, fps, _ = probeVideoProps(pctx, videoPath)
		}
	}

	// 4) Meta schreiben/aktualisieren:
	//    - schreibt resolution (über formatResolution) nur wenn vw/vh > 0
	//    - schreibt sourceURL wenn vorhanden
	if durSec > 0 {
		_ = writeVideoMeta(metaPath, fi, durSec, vw, vh, fps, sourceURL)
	}

	// Gewichte: thumbs klein, preview groß
	const (
		thumbsW  = 0.25
		previewW = 0.75
	)

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

	progress(0)

	// ----------------
	// Thumbs
	// ----------------
	thumbPath := filepath.Join(assetDir, "thumbs.jpg")
	if tfi, err := os.Stat(thumbPath); err == nil && !tfi.IsDir() && tfi.Size() > 0 {
		progress(thumbsW)
	} else {
		progress(0.05)

		genCtx, cancel := context.WithTimeout(context.Background(), 45*time.Second)
		defer cancel()

		if err := thumbSem.Acquire(genCtx); err != nil {
			// best-effort
			progress(thumbsW)
			goto PREVIEW
		}
		defer thumbSem.Release()

		progress(0.10)

		t := 0.0
		if durSec > 0 {
			t = durSec * 0.5
		}

		progress(0.15)

		img, e1 := extractFrameAtTimeJPEG(videoPath, t)
		if e1 != nil || len(img) == 0 {
			img, e1 = extractLastFrameJPEG(videoPath)
			if e1 != nil || len(img) == 0 {
				img, e1 = extractFirstFrameJPEG(videoPath)
			}
		}

		progress(0.20)

		if e1 == nil && len(img) > 0 {
			if err := atomicWriteFile(thumbPath, img); err != nil {
				fmt.Println("⚠️ thumb write:", err)
			}
		}

		progress(thumbsW)
	}

PREVIEW:
	// ----------------
	// Preview
	// ----------------
	previewPath := filepath.Join(assetDir, "preview.mp4")
	if pfi, err := os.Stat(previewPath); err == nil && !pfi.IsDir() && pfi.Size() > 0 {
		progress(1)
		return nil
	}

	genCtx, cancel := context.WithTimeout(context.Background(), 3*time.Minute)
	defer cancel()

	progress(thumbsW + 0.02)

	if err := genSem.Acquire(genCtx); err != nil {
		progress(1)
		return nil
	}
	defer genSem.Release()

	progress(thumbsW + 0.05)

	if err := generateTeaserClipsMP4WithProgress(genCtx, videoPath, previewPath, 1.0, 18, func(r float64) {
		if r < 0 {
			r = 0
		}
		if r > 1 {
			r = 1
		}
		progress(thumbsW + r*previewW)
	}); err != nil {
		fmt.Println("⚠️ preview clips:", err)
	}

	progress(1)
	return nil
}