# core/encode_engine.py
"""FFmpeg encoding engine with comprehensive logging."""

import subprocess
from pathlib import Path

from core.audio_handler import get_audio_streams, choose_audio_bitrate, filter_audio_streams, prompt_user_audio_selection, prompt_for_title_stripping
from core.video_handler import calculate_crop_dimensions
from core.logger_helper import setup_logger

logger = setup_logger(Path(__file__).parent.parent / "logs")


def run_ffmpeg(input_file: Path, output_file: Path, cq: int, scale_width: int, scale_height: int,
               src_width: int, src_height: int, filter_flags: str, audio_config: dict, 
               method: str, bitrate_config: dict, encoder: str = "nvenc", subtitle_files: list = None, audio_language: str = None,
               audio_filter_config: dict = None, test_mode: bool = False, strip_all_titles: bool = False, src_bit_depth: int = None, unforce_subs: bool = False, no_encode: bool = False, color_bit: int = None, crop_height: int = None, audio_titles: dict = None, audio_channels: dict = None):
    """
    Execute FFmpeg encoding/re-muxing with structured console output.
    
    Args:
        input_file: Path to source video file
        output_file: Path for encoded output file
        cq: Quality value (0-63, lower=better) for CQ mode
        scale_width/height: Target resolution dimensions
        src_width/height: Source resolution dimensions
        filter_flags: Scaling filter algorithm (lanczos, bicubic, etc)
        audio_config: Audio bitrate configuration dict
        method: Encoding method - "CQ" or "Bitrate"
        bitrate_config: Bitrate/maxrate/bufsize configuration dict
        encoder: Video codec - "hevc", "av1", or "nvenc"
        subtitle_files: List of external subtitle file paths (if any)
        audio_language: ISO 639-2 language code to tag audio (e.g., "eng", "spa")
        audio_filter_config: Audio filtering/selection configuration
        test_mode: If True, only encode first 15 minutes, don't move files
        strip_all_titles: If True, strip title metadata from all audio tracks
        src_bit_depth: Source bit depth (8/10/12) for encoder auto-selection
        unforce_subs: If True, remove forced flag from subtitle tracks
        no_encode: If True, copy video/audio (re-mux only, skip encoding)
        color_bit: If specified (8 or 10), forces HEVC color bit depth. 8-bit uses yuv420p, 10-bit uses p010le.
        crop_height: If specified, crop video to this height (centered). E.g., 816 for 1920x816 from 1920x1080 source.
        audio_titles: Dict mapping stream index to custom title. E.g., {1: "Commentary"} sets stream 1 title to "Commentary".
        audio_channels: Dict mapping stream index to channel count. E.g., {0: 2, 1: 6} forces track 0 to stereo, track 1 to 5.1. Only 2 or 6 allowed.
    
    Returns:
        tuple: (orig_size_bytes, output_size_bytes, reduction_ratio)
    """
    streams = get_audio_streams(input_file)
    
    # Apply audio filter if enabled
    if audio_filter_config and audio_filter_config.get("enabled", False):
        # Check if pre-selected streams provided
        if audio_filter_config.get("preselected"):
            # Use pre-selected streams (skip interactive)
            preselected_str = audio_filter_config["preselected"]
            try:
                selected_indices = set()
                for part in preselected_str.split(","):
                    idx = int(part.strip())
                    selected_indices.add(idx)
                # Filter to only selected streams
                streams = [s for s in streams if s[0] in selected_indices]
                logger.info(f"Pre-selected audio streams: {[s[0] for s in streams]}")
            except ValueError:
                logger.warning(f"Invalid audio_select format: {preselected_str}. Using all streams.")
        else:
            # Check if interactive mode requested (via --filter-audio CLI flag)
            # If audio_filter_config came from CLI, it has "interactive": True
            if "interactive" in audio_filter_config and audio_filter_config.get("interactive", False):
                # Interactive audio selection (show prompt to user)
                streams = prompt_user_audio_selection(streams)
                # Prompt for title stripping after stream selection
                streams = prompt_for_title_stripping(streams)
            else:
                # Automatic filtering from config (keep best English + Commentary)
                streams = filter_audio_streams(input_file, streams)
    
    # Determine encoder display name and settings
    if encoder == "av1":
        encoder_name = "AV1 NVENC"
        encoder_codec = "av1_nvenc"
        encoder_preset = "p7"  # p7 = fastest/lower quality (0-7 scale)
        encoder_pix_fmt = "yuv420p"
        encoder_bit_depth = "8-bit"
    else:  # default hevc = HEVC NVENC
        encoder_name = "HEVC NVENC"
        encoder_codec = "hevc_nvenc"
        encoder_preset = "p7"  # p7 = fastest/lower quality (0-7 scale)
        encoder_pix_fmt = "p010le"
        encoder_bit_depth = "10-bit"
    
    # Handle --color-bit override if specified (only for HEVC)
    if color_bit is not None and encoder == "hevc":
        if color_bit == 8:
            encoder_pix_fmt = "yuv420p"
            encoder_bit_depth = "8-bit"
            logger.info(f"Using --color-bit {color_bit}: HEVC NVENC 8-bit (yuv420p)")
        elif color_bit == 10:
            encoder_pix_fmt = "p010le"
            encoder_bit_depth = "10-bit"
            logger.info(f"Using --color-bit {color_bit}: HEVC NVENC 10-bit (p010le)")
    # Auto-select encoder based on detected source bit depth if provided (only if --color-bit not specified)
    elif src_bit_depth is not None and color_bit is None:
        if src_bit_depth >= 10:
            # Source is 10-bit or higher - use HEVC NVENC
            encoder_name = "HEVC NVENC"
            encoder_codec = "hevc_nvenc"
            encoder_preset = "p7"
            encoder_pix_fmt = "p010le"
            encoder_bit_depth = "10-bit"
            logger.info(f"Auto-selected HEVC NVENC for detected {src_bit_depth}-bit source")
        else:
            # Source is 8-bit - use AV1 NVENC
            encoder_name = "AV1 NVENC"
            encoder_codec = "av1_nvenc"
            encoder_preset = "p7"
            encoder_pix_fmt = "yuv420p"
            encoder_bit_depth = "8-bit"
            logger.info(f"Auto-selected AV1 NVENC for detected {src_bit_depth}-bit source")
    
    # Debug: log audio_language received
    logger.debug(f"audio_language parameter: {audio_language}")
    
    # Build simple console summary
    audio_summary_lines = []
    for (index, channels, avg_bitrate, src_lang, meta_bitrate, title, codec_name) in streams:
        # Determine final title (considering custom titles override)
        final_title = audio_titles.get(index, title) if audio_titles else title
        
        # Check if this is a commentary track (original or custom title)
        is_commentary = final_title and "commentary" in final_title.lower()
        
        # Determine output channels: audio_channels override takes precedence
        is_1080_class = scale_height >= 1080 or scale_width >= 1920
        if audio_channels and index in audio_channels:
            # User explicitly specified channel count for this stream
            output_channels = audio_channels[index]
            channels_override = True
        elif is_commentary:
            output_channels = 2  # Commentary always stereo
            channels_override = False
        else:
            output_channels = 6 if is_1080_class and channels >= 6 else 2
            channels_override = False
        
        codec, br = choose_audio_bitrate(output_channels, avg_bitrate, audio_config, is_1080_class, is_commentary)
        
        if codec == "copy":
            action = "COPY"
            output_codec = codec_name
            output_bitrate = f"{avg_bitrate}kbps"
        else:
            action = "ENC"
            # Determine output codec based on encode choice
            output_codec = "EAC3" if codec == "eac3" else "AAC"
            output_bitrate = f"{br/1000:.0f}kbps"
        
        # Show language change if audio_language is set
        lang_info = f"{src_lang} → {audio_language}" if audio_language else src_lang
        
        # Include title in display if present
        title_info = f" [{final_title}]" if final_title else ""
        # Add override note if channels were forced
        override_note = " [FORCED]" if channels_override else ""
        line = f"    - Stream #{index}: {channels}ch→{output_channels}ch | {lang_info} | Detected: {codec_name} {avg_bitrate}kbps | Output: {output_codec} {output_bitrate} ({action}){title_info}{override_note}"
        audio_summary_lines.append(line)

    cmd = ["ffmpeg","-y","-i",str(input_file)]
    
    # Add subtitle inputs if present
    if subtitle_files:
        for sub_file in subtitle_files:
            cmd.extend(["-i", str(sub_file)])
    
    # In test mode, only encode first 15 minutes
    if test_mode:
        cmd.extend(["-t", "900"])  # 900 seconds = 15 minutes
    
    # Build video filters (crop and/or scale)
    video_filters = []
    
    # Add crop filter first (if specified)
    if crop_height and not no_encode:
        crop_dims = calculate_crop_dimensions(src_height, crop_height)
        if crop_dims["ffmpeg_filter"]:
            video_filters.append(crop_dims["ffmpeg_filter"])
            print(f"ℹ️  Applying crop: {crop_dims['ffmpeg_filter']} ({src_height}p → {crop_height}p)")
    
    # Add scale filter (if encoding, not copying)
    if not no_encode:
        video_filters.append(f"scale={scale_width}:{scale_height}:flags={filter_flags}:force_original_aspect_ratio=decrease")
    
    # Combine all filters with commas (ffmpeg filter chain syntax)
    if video_filters:
        filter_chain = ",".join(video_filters)
        cmd.extend(["-vf", filter_chain])
    
    cmd.extend(["-map","0:v:0"])  # Map only first actual video stream (skips attached pictures)
    
    # Map only selected audio streams
    for index, _, _, _, _, _, _ in streams:
        cmd.extend(["-map", f"0:{index}"])
    
    # Add subtitle mapping if present
    if subtitle_files:
        for i, _ in enumerate(subtitle_files):
            cmd.extend(["-map", f"{i+1}:s"])
    else:
        cmd.extend(["-map", "0:s?"])
    
    # Video codec: copy if no_encode, otherwise use specified encoder
    if no_encode:
        cmd.extend(["-c:v", "copy"])
    else:
        cmd.extend([
            "-c:v", encoder_codec, "-preset", encoder_preset, "-pix_fmt", encoder_pix_fmt])

        if method=="CQ":
            cmd += ["-cq", str(cq)]
        else:
            # Use bitrate config (fallback mode)
            res_key = "1080" if scale_height >= 1080 or scale_width >= 1920 else "720"
            vb = bitrate_config.get(f"bitrate_{res_key}", "900k")
            maxrate = bitrate_config.get(f"maxrate_{res_key}", "1250k")
            bufsize = bitrate_config.get(f"bufsize_{res_key}", "1800k")
            cmd += ["-b:v", vb, "-maxrate", maxrate, "-bufsize", bufsize]

    for i, (index, channels, avg_bitrate, src_lang, meta_bitrate, title, codec_name) in enumerate(streams):
        # Determine final title (considering custom titles override)
        final_title = audio_titles.get(index, title) if audio_titles else title
        
        # Debug: Log what we're working with
        if i == 0:  # Only log once per file
            logger.debug(f"audio_titles dict received: {audio_titles}")
        logger.debug(f"Stream {index}: original_title='{title}', final_title='{final_title}', audio_titles_present={audio_titles is not None}")
        
        # Check if this is a commentary track (original or custom title)
        is_commentary = final_title and "commentary" in final_title.lower()
        
        # Determine output channels: audio_channels override takes precedence
        # BUT: Commentary tracks ALWAYS max out at 2ch (stereo) unless explicitly overridden
        is_1080_class = scale_height >= 1080 or scale_width >= 1920
        if audio_channels and index in audio_channels:
            # User explicitly specified channel count for this stream
            output_channels = audio_channels[index]
            logger.info(f"Stream #{index}: Audio channels override applied: {channels}ch → {output_channels}ch")
        elif is_commentary:
            output_channels = 2  # Commentary always stereo
        else:
            output_channels = 6 if is_1080_class and channels >= 6 else 2
        
        # If no_encode is True, always copy audio
        if no_encode:
            codec, br = "copy", avg_bitrate
        else:
            codec, br = choose_audio_bitrate(output_channels, avg_bitrate, audio_config, is_1080_class, is_commentary)
        
        # Check if title should be stripped (for this stream or globally)
        # Preserve any stream with "commentary" or "descriptive" in the title, regardless of strip_all_titles
        is_special_audio = title and ("commentary" in title.lower() or "descriptive" in title.lower())
        should_strip = strip_all_titles and not is_special_audio
        
        # Log title stripping decisions for debugging (debug level, not info)
        logger.debug(f"Stream {index}: title='{final_title}', is_commentary={is_commentary}, is_special_audio={is_special_audio}, strip_all_titles={strip_all_titles}, should_strip={should_strip}")
        
        if is_commentary:
            logger.info(f"Stream #{index}: Commentary track detected (forcing 2ch stereo)")
        
        if strip_all_titles and is_special_audio:
            logger.debug(f"Stream {index}: ✓ Preserving title '{title}' (special audio track)")
        
        if codec == "copy":
            # Preserve original audio
            cmd += [f"-c:a:{i}", "copy"]
            # Only add language metadata if explicitly provided
            if audio_language:
                cmd += [f"-metadata:s:a:{i}", f"language={audio_language}"]
            # Apply custom title if provided for this stream (takes precedence)
            if audio_titles and index in audio_titles:
                cmd += [f"-metadata:s:a:{i}", f"title={audio_titles[index]}"]
            # Strip title metadata if requested (but preserve commentary tracks and custom titles)
            elif should_strip:
                cmd += [f"-metadata:s:a:{i}", "title="]
        else:
            # Re-encode with target bitrate
            # EAC3 for multichannel, AAC for stereo
            if codec == "eac3":
                # Enhanced AC-3 (5.1 surround)
                cmd += [
                    f"-c:a:{i}", "eac3",
                    f"-b:a:{i}", str(br),
                    f"-ac:{i}", str(output_channels),
                    f"-channel_layout:a:{i}", "5.1"
                ]
            else:
                # AAC (stereo)
                cmd += [
                    f"-c:a:{i}", "aac",
                    f"-b:a:{i}", str(br),
                    f"-ac:{i}", str(output_channels),
                    f"-channel_layout:a:{i}", "stereo"
                ]
            # Only add language metadata if explicitly provided
            if audio_language:
                cmd += [f"-metadata:s:a:{i}", f"language={audio_language}"]
            # Apply custom title if provided for this stream (takes precedence)
            if audio_titles and index in audio_titles:
                cmd += [f"-metadata:s:a:{i}", f"title={audio_titles[index]}"]
            # Strip title metadata if requested (but preserve commentary tracks and custom titles)
            elif should_strip:
                cmd += [f"-metadata:s:a:{i}", "title="]
    # Add subtitle codec and metadata if subtitles are present
    if subtitle_files:
        cmd += ["-c:s", "srt"]
        for i in range(len(subtitle_files)):
            cmd += ["-metadata:s:s:" + str(i), "language=eng"]
            if unforce_subs:
                cmd += ["-disposition:s:" + str(i), "-forced"]
    else:
        # Convert mov_text (MP4 subtitles) to subrip (MKV-compatible)
        # Use "copy" for other formats like subrip, ass, ssa, webvtt that work in MKV
        cmd += ["-c:s", "subrip"]
        # For embedded subtitles, still apply -disposition if unforce_subs is enabled
        if unforce_subs:
            # Apply to all embedded subtitle streams
            cmd += ["-disposition:s", "-forced"]
    
    cmd += [str(output_file)]

    # Print detailed console output with VIDEO and AUDIO sections
    print(f"\n🎬 Encoding: {output_file.name}")
    
    # VIDEO SECTION
    print(f"📹 VIDEO")
    
    # Build resolution and bit depth info
    detected_bit = f" {src_bit_depth}-bit" if src_bit_depth else ""
    output_bit = f" {encoder_bit_depth}"
    
    if scale_width != src_width or scale_height != src_height:
        res_info = f"Detected: {src_width}x{src_height}{detected_bit} | Output: {scale_width}x{scale_height}{output_bit}"
    else:
        res_info = f"Detected: {src_width}x{src_height}{detected_bit} | Output: {scale_width}x{scale_height}{output_bit}"
    
    cq_info = f"CQ {cq}" if method == "CQ" else f"VBR {bitrate_config.get('bitrate_1080', '900k')}"
    test_str = " [TEST 15min]" if test_mode else ""
    print(f"   {res_info} | {encoder_name} preset {encoder_preset} | {cq_info}{test_str}")
    
    # AUDIO SECTION
    print(f"🔊 AUDIO")
    for line in audio_summary_lines:
        print(line)
    
    logger.debug(f"Running {method} encode: {output_file.name}")

    # Run FFmpeg with stderr/stdout captured (hide version/config info)
    process = subprocess.Popen(
        cmd,
        stdout=subprocess.PIPE,
        stderr=subprocess.STDOUT,
        text=True,
        bufsize=1
    )
    
    # Print progress section header
    print(f"\n⏳ PROGRESS")
    
    # Read output line by line but only print progress-related lines
    ffmpeg_log = []
    import re
    for line in process.stdout:
        ffmpeg_log.append(line.rstrip())
        # Only print progress lines (frame= indicates encoding progress)
        if "frame=" in line:
            # Extract key metrics: time, bitrate, and elapsed
            time_match = re.search(r'time=(\S+)', line)
            bitrate_match = re.search(r'bitrate=(\S+)', line)
            elapsed_match = re.search(r'elapsed=(\S+)', line)
            
            time_str = time_match.group(1) if time_match else "00:00:00"
            bitrate_str = bitrate_match.group(1) if bitrate_match else "0kbps"
            elapsed_str = elapsed_match.group(1) if elapsed_match else "0:00:00"
            
            # Print with carriage return to update same line (no newline, use \r to go back to start)
            print(f"\r   {time_str} | {bitrate_str} | elapsed={elapsed_str}", end='', flush=True)
    
    print()  # Newline after encoding completes
    
    returncode = process.wait()
    if returncode != 0:
        # Log full FFmpeg output if there was an error
        logger.error("FFmpeg output (full):")
        for line in ffmpeg_log:
            logger.error(line)
        raise subprocess.CalledProcessError(returncode, cmd)

    orig_size = input_file.stat().st_size
    out_size = output_file.stat().st_size
    reduction_ratio = out_size / orig_size
    
    # Log comprehensive results
    logger.info(f"\n📊 ENCODE RESULTS:")
    logger.info(f"  Original Size: {orig_size/1e6:.2f} MB")
    logger.info(f"  Encoded Size:  {out_size/1e6:.2f} MB")
    logger.info(f"  Reduction:     {reduction_ratio:.1%} of original ({(1-reduction_ratio):.1%} saved)")
    logger.info(f"  Resolution:    {src_width}x{src_height} → {scale_width}x{scale_height}")
    logger.info(f"  Audio Streams: {len(streams)} streams processed")
    
    msg = f"📦 Original: {orig_size/1e6:.2f} MB → Encoded: {out_size/1e6:.2f} MB ({reduction_ratio:.1%} of original)"
    print(msg)

    return orig_size, out_size, reduction_ratio