"""FFmpeg/FFprobe interaction utilities for the web backend."""

import subprocess
import json


def get_stream_info(input_file: str):
    """
    Retrieve stream information (audio, video, subtitle presence) from a media file.
    Returns a dict with keys: has_audio, has_video, has_subtitle, audio_codec.
    """
    # Get audio codec (if any)
    audio_codec = None
    try:
        cmd = [
            'ffprobe', '-v', 'error',
            '-select_streams', 'a:0',
            '-show_entries', 'stream=codec_name',
            '-of', 'default=noprint_wrappers=1:nokey=1',
            input_file
        ]
        result = subprocess.run(cmd, capture_output=True, text=True, check=False)
        codec = result.stdout.strip().lower()
        if codec:
            audio_codec = codec
    except Exception:
        pass

    # Check for video stream
    has_video = False
    try:
        cmd = [
            'ffprobe', '-v', 'error',
            '-select_streams', 'v',
            '-show_entries', 'stream=codec_type',
            '-of', 'default=noprint_wrappers=1:nokey=1',
            input_file
        ]
        result = subprocess.run(cmd, capture_output=True, text=True, check=False)
        has_video = bool(result.stdout.strip())
    except Exception:
        pass

    # Check for subtitle stream
    has_subtitle = False
    try:
        cmd = [
            'ffprobe', '-v', 'error',
            '-select_streams', 's',
            '-show_entries', 'stream=codec_type',
            '-of', 'default=noprint_wrappers=1:nokey=1',
            input_file
        ]
        result = subprocess.run(cmd, capture_output=True, text=True, check=False)
        has_subtitle = bool(result.stdout.strip())
    except Exception:
        pass

    return {
        'has_audio': audio_codec is not None,
        'has_video': has_video,
        'has_subtitle': has_subtitle,
        'audio_codec': audio_codec,
    }


def get_audio_duration(input_file: str) -> float:
    """Get the duration of the audio file in seconds."""
    cmd = [
        'ffprobe', '-v', 'error',
        '-show_entries', 'format=duration',
        '-of', 'default=noprint_wrappers=1:nokey=1',
        input_file
    ]
    result = subprocess.run(cmd, capture_output=True, text=True, check=False)
    try:
        return float(result.stdout.strip())
    except ValueError:
        return 0.0