import os
import json
import hashlib
import subprocess
from datetime import datetime, timezone

VIDEO_EXTENSIONS = {".mp4", ".mkv", ".avi", ".mov", ".webm", ".flv", ".wmv", ".m4v"}
BACKUP_KEYWORDS = {"backup", "backups", "#recycle"}

MEDIA_ROOT = os.environ.get("MEDIA_ROOT", "/mnt/mediaserver")
SCAN_DIRS = os.environ.get("SCAN_DIRS", "Youtube,Movies,TV").split(",")
INDEX_PATH = os.environ.get("INDEX_PATH", "/home/jarian/projects/media-transcriber/index.json")
TRANSCRIPTS_DIR = os.environ.get("TRANSCRIPTS_DIR", "/home/jarian/projects/media-transcriber/transcripts")


def is_video(path):
    return os.path.splitext(path)[1].lower() in VIDEO_EXTENSIONS


def is_backup(path):
    parts = path.replace(MEDIA_ROOT, "").split("/")
    return any(k.lower() in {p.lower() for p in parts} for k in BACKUP_KEYWORDS)


def video_hash(filepath):
    stat = os.stat(filepath)
    raw = f"{stat.st_size}:{stat.st_mtime_ns}:{filepath}"
    return hashlib.sha256(raw.encode()).hexdigest()[:16]


def get_duration(filepath):
    try:
        result = subprocess.run(
            ["ffprobe", "-v", "error", "-show_entries", "format=duration",
             "-of", "default=noprint_wrappers=1:nokey=1", filepath],
            capture_output=True, text=True, timeout=10
        )
        return round(float(result.stdout.strip()), 2)
    except Exception:
        return None


def transcript_exists(rel_path):
    full_path = os.path.join(MEDIA_ROOT, rel_path)
    parent = os.path.dirname(full_path)
    trans_dir = os.path.join(parent, "_transcriptions")
    base = os.path.splitext(os.path.basename(full_path))[0]
    for ext in (".srt", ".vtt", ".txt", ".json"):
        candidate = os.path.join(trans_dir, f"{base}_transcription{ext}")
        if os.path.exists(candidate):
            return True, candidate
    return False, None


def scan(skip_duration=False):
    videos = {}
    now = datetime.now(timezone.utc).isoformat()
    for scan_dir in SCAN_DIRS:
        root = os.path.join(MEDIA_ROOT, scan_dir)
        if not os.path.isdir(root):
            continue
        for dirpath, _, filenames in os.walk(root):
            for fname in filenames:
                full = os.path.join(dirpath, fname)
                if not is_video(full) or is_backup(full):
                    continue
                rel = os.path.relpath(full, MEDIA_ROOT)
                has_transcript, transcript_file = transcript_exists(rel)
                vid_hash = video_hash(full)
                stat = os.stat(full)
                videos[rel] = {
                    "path": full,
                    "hash": vid_hash,
                    "duration_seconds": None if skip_duration else get_duration(full),
                    "size_bytes": stat.st_size,
                    "transcribed": has_transcript,
                    "transcript_file": transcript_file,
                    "last_scanned": now,
                }

    transcribed_count = sum(1 for v in videos.values() if v["transcribed"])
    index = {
        "version": "1",
        "last_updated": now,
        "total_videos": len(videos),
        "transcribed": transcribed_count,
        "videos": videos,
    }

    tmp = INDEX_PATH + ".tmp"
    with open(tmp, "w") as f:
        json.dump(index, f, indent=2)
    os.replace(tmp, INDEX_PATH)

    return index