import json
import os
import sys
import tempfile
from typing import Optional

import ffmpeg
import typer
from loguru import logger
from PIL import Image
from tqdm import tqdm

logger.remove()
logger.add(
    sys.stderr,
    format="<d>{time:YYYY-MM-DD ddd HH:mm:ss}</d> | <lvl>{level}</lvl> | <lvl>{message}</lvl>",
)
app = typer.Typer(pretty_exceptions_show_locals=False)

# Vertical placements accepted by extract_frames' text_y_position.
TEXT_Y_POSITIONS = ("top", "middle", "bottom")


def parse_frame_name(fname: str):
    """return a tuple of frame_type and frame_index

    Splits on the last underscore so frame types that themselves contain
    underscores (e.g. ``my_clip``) still round-trip.

    >>> parse_frame_name("clip_12.jpg")
    ('clip', 12)
    >>> parse_frame_name("my_clip_12.jpg")
    ('my_clip', 12)
    """
    fn, fext = os.path.splitext(os.path.basename(fname))
    frame_type, frame_index = fn.rsplit("_", 1)
    return frame_type, int(frame_index)


def _drawtext_escape(text: str) -> str:
    r"""Escape a literal string for ffmpeg's ``drawtext`` text expansion.

    The overlay text is passed to drawtext via ``textfile=`` (see
    :func:`extract_frames`), so the file content skips filtergraph parsing
    entirely and only drawtext's *text expansion* applies: ``\`` escapes the
    next character and a bare ``%`` starts a ``%{...}`` sequence that silently
    breaks rendering. Everything else (quotes, colons, commas, spaces) is
    literal.

    Args:
        text (str): Raw text to render verbatim.

    Returns:
        str: The escaped text.

    >>> _drawtext_escape("50% off: it's, fine")
    "50\\% off: it's, fine"
    >>> _drawtext_escape("a\\b")
    'a\\\\b'
    """
    return text.replace("\\", "\\\\").replace("%", "\\%")


def _build_drawtext_text(
    write_timestamp: bool,
    write_frame_num: bool,
    text_overlay: Optional[str] = None,
) -> str:
    """Build the ``drawtext`` overlay text (the ``textfile=`` content).

    Parts are joined with `` |`` on a single line: an optional caller-supplied
    prefix (``text_overlay``, escaped via :func:`_drawtext_escape`), then the
    timestamp, then the frame number. The frame number is only shown when the
    timestamp is (matching :func:`extract_frames`'s historical behavior). The
    string is a drawtext text-expansion template — it must reach drawtext
    verbatim, which is why :func:`extract_frames` passes it via a temp file
    (``textfile=``) instead of inline (``text=``, whose filtergraph escaping
    cannot express every literal string).

    Args:
        write_timestamp (bool): Include the ``%{pts:hms}`` timestamp part.
        write_frame_num (bool): Include the ``%{frame_num}`` part (only takes
            effect when ``write_timestamp`` is True).
        text_overlay (str | None): Custom literal text prefixed to the line.

    Returns:
        str: The drawtext text-expansion template.

    >>> _build_drawtext_text(True, True)
    'Timestamp:%{pts:hms} |Frame Number: %{frame_num}'
    >>> _build_drawtext_text(True, False)
    'Timestamp:%{pts:hms}'
    >>> _build_drawtext_text(False, False, "cam-1")
    'cam-1'
    >>> _build_drawtext_text(True, True, "cam-1")
    'cam-1 |Timestamp:%{pts:hms} |Frame Number: %{frame_num}'
    """
    parts = []
    if text_overlay:
        parts.append(_drawtext_escape(text_overlay))
    if write_timestamp:
        parts.append("Timestamp:%{pts:hms}")
        if write_frame_num:
            parts.append("Frame Number: %{frame_num}")
    return " |".join(parts)


@app.command()
def get_video_metadata(video_path: str, bverbose: bool = True):
    """
    Extract comprehensive metadata from a video file.

    Args:
        video_path (str): Path to the video file

    Returns:
        dict: Dictionary containing video metadata including:
            - width, height: Video dimensions
            - duration: Video duration in seconds
            - fps: Frames per second
            - codec: Video codec name
            - bitrate: Video bitrate
            - format_name: Container format
            - file_size: File size in bytes
    """
    probe = ffmpeg.probe(video_path)

    # Find the first video stream
    video_stream = next(
        (stream for stream in probe["streams"] if stream["codec_type"] == "video"),
        None,
    )

    if video_stream is None:
        raise ValueError("No video stream found")

    # Get format information (also the fallback source for duration)
    format_info = probe.get("format", {})

    # Extract basic video properties
    width = int(video_stream.get("width", 0))
    height = int(video_stream.get("height", 0))
    # Duration is not always present on the video stream (e.g. MKV/WebM);
    # fall back to the container/format duration so callers don't silently get 0.
    duration = float(video_stream.get("duration") or format_info.get("duration", 0))

    # Calculate FPS
    r_frame_rate = video_stream.get("r_frame_rate", "0/1")
    num, denom = map(int, r_frame_rate.split("/"))
    fps = num / denom if denom != 0 else 0

    # Get codec and bitrate
    codec = video_stream.get("codec_name", "unknown")
    bitrate = (
        int(video_stream.get("bit_rate", 0)) if video_stream.get("bit_rate") else 0
    )

    format_name = format_info.get("format_name", "unknown")
    file_size = int(format_info.get("size", 0))

    # Get audio stream info if available
    audio_stream = next(
        (stream for stream in probe["streams"] if stream["codec_type"] == "audio"),
        None,
    )

    audio_codec = audio_stream.get("codec_name", "none") if audio_stream else "none"
    audio_bitrate = (
        int(audio_stream.get("bit_rate", 0))
        if audio_stream and audio_stream.get("bit_rate")
        else 0
    )

    metadata = {
        "width": width,
        "height": height,
        "duration": duration,
        "fps": fps,
        "video_codec": codec,
        "video_bitrate": bitrate,
        "audio_codec": audio_codec,
        "audio_bitrate": audio_bitrate,
        "format_name": format_name,
        "file_size": file_size,
        "total_streams": len(probe["streams"]),
    }
    if bverbose:
        logger.info(f"Video metadata extracted: {json.dumps(metadata, indent=4)}")
    return metadata


@app.command()
def extract_frames(
    input_path: str,
    fps: Optional[float] = 8,
    max_short_edge: int = 1080,
    write_timestamp: bool = True,
    write_frame_num: bool = True,
    output_dir: Optional[str] = None,
    out_vid_path: Optional[str] = None,
    text_overlay: Optional[str] = None,
    text_font_size: int = 20,
    text_y_position: str = "bottom",
):
    """
    Extract frames from a video file using FFmpeg.

    Args:
        input_path (str): Path to the input video file.
        fps (float | None): Frames per second to extract; capped to the source
            fps. Pass ``None`` to skip resampling and extract *every* native
            frame (so output index i == source frame i — needed for
            frame-accurate, per-frame annotation).
        max_short_edge (int): Maximum length of the shorter edge of the extracted frames.
        write_timestamp (bool): Whether to write the timestamp of each frame.
        write_frame_num (bool): Whether to write the frame number of each frame.
        output_dir (str): Directory to save the extracted frames.
        out_vid_path (str): Path to save the extracted frames as a video.
        text_overlay (str | None): Custom literal text prefixed to the overlay
            line (escaped for drawtext). Drawn even when ``write_timestamp`` is
            False, so it can be used on its own.
        text_font_size (int): Font size of the timestamp/frame-number overlay.
        text_y_position (str): Vertical placement of the overlay. One of
            "top", "middle", or "bottom" (default).

    Returns:
        List of PIL Images
    """
    y_position_map = {
        "top": "2*lh",
        "middle": "(h-lh)/2",
        "bottom": "h-(2*lh)",
    }
    assert (
        text_y_position in TEXT_Y_POSITIONS
    ), f"text_y_position must be one of {list(TEXT_Y_POSITIONS)}, got {text_y_position!r}"
    text_y_expr = y_position_map[text_y_position]

    if output_dir:
        assert os.path.isdir(
            output_dir
        ), f"Output directory {output_dir} does not exist"

    # Probe video to get width, height, and duration
    vmeta = get_video_metadata(input_path, bverbose=False)
    org_w, org_h = vmeta["width"], vmeta["height"]
    max_short_edge = int(max_short_edge) if max_short_edge else min(org_w, org_h)
    long_edge = int((max(org_h, org_w) / min(org_h, org_w)) * max_short_edge)
    long_edge += 0 if long_edge % 2 == 0 else 1
    duration = vmeta["duration"]
    org_fps = vmeta["fps"]
    if fps is not None and fps > org_fps:
        logger.debug(
            f"requested fps({fps}) exceeded source fps({org_fps}): fps will be capped to source fps({org_fps})"
        )
        fps = org_fps

    # Calculate total frames to extract (only a progress-bar estimate). With
    # fps=None every native frame is read, so estimate off the source fps.
    total_frames = int(duration * (org_fps if fps is None else fps))

    # add scale filter only if needed
    add_scale_filter = max_short_edge < min(org_w, org_h)
    w = max_short_edge if org_w < org_h else long_edge
    h = max_short_edge if org_w > org_h else long_edge
    logger.debug(f"Video dimensions: {org_w}x{org_h}")
    if add_scale_filter:
        logger.debug(f"\tscaling video to {w}x{h}")

    # Setup the ffmpeg filter chain (each entry is comma-joined). fps=None skips
    # resampling entirely so every native frame is emitted. The drawtext text
    # goes through a temp file (textfile=) rather than inline (text=): the file
    # content skips filtergraph parsing, so arbitrary overlay text (quotes,
    # colons, %) can't break the chain.
    filters = []
    drawtext_file = None
    if fps is not None:
        filters.append(f"fps={fps}")
    if write_timestamp or text_overlay:
        with tempfile.NamedTemporaryFile(
            "w", suffix=".txt", delete=False, encoding="utf-8"
        ) as tf:
            tf.write(_build_drawtext_text(write_timestamp, write_frame_num, text_overlay))
            drawtext_file = tf.name
        filters.append(
            f"drawtext=textfile={drawtext_file}: x=(w-tw)/2: y={text_y_expr}: fontcolor=white: fontsize={text_font_size}: box=1: boxcolor=0x00000099: boxborderw=5"
        )
    if add_scale_filter:
        filters.append(f"scale='{w}:{h}'")
    filter_chain = ",".join(filters)

    # Run ffmpeg process with output as rawvideo piped to stdout.
    # NOTE: stderr is intentionally left to inherit (not piped). If it were
    # piped without being drained, ffmpeg would block once the OS pipe buffer
    # fills, deadlocking against our stdout-only read loop on longer clips.
    # The try/finally keeps the drawtext textfile alive through both ffmpeg
    # runs (extraction + optional re-encode) and removes it afterwards.
    try:
        output_kwargs = {"format": "rawvideo", "pix_fmt": "rgb24"}
        if filter_chain:  # omit an empty -vf (invalid); no filter = passthrough
            output_kwargs["vf"] = filter_chain
        process = (
            ffmpeg.input(input_path)
            .output("pipe:", **output_kwargs)
            .run_async(pipe_stdout=True)
        )
        logger.info(f"running ffmpeg with filter:\n{filter_chain or '(none)'}")

        frame_size = (
            long_edge * max_short_edge * 3 if add_scale_filter else org_w * org_h * 3
        )  # 3 bytes per pixel (RGB)
        frames = []

        # total_frames (duration * fps) is only an estimate for the progress bar;
        # read until the pipe is exhausted so we don't drop the tail frame or stop
        # before EOF when the estimate is slightly off.
        with tqdm(total=total_frames, desc="Extracting frames with FFMPEG") as pbar:
            while True:
                in_bytes = process.stdout.read(frame_size)
                if not in_bytes or len(in_bytes) < frame_size:
                    break
                frame = Image.frombytes(
                    "RGB", (w, h) if add_scale_filter else (org_w, org_h), in_bytes
                )
                frames.append(frame)
                pbar.update(1)

        process.stdout.close()
        process.wait()

        if output_dir:
            vname, _ = os.path.splitext(os.path.basename(input_path))
            for i, im in enumerate(tqdm(frames, desc=f"Saving frames to {output_dir}")):
                output_path = os.path.join(output_dir, f"{vname}_{i}.jpg")
                im.save(output_path)

        if out_vid_path:
            vid_kwargs = {
                "vcodec": "libx264",
                "pix_fmt": "yuv420p",
                "r": org_fps if fps is None else fps,
            }
            if filter_chain:
                vid_kwargs["vf"] = filter_chain
            ffmpeg.input(input_path).output(out_vid_path, **vid_kwargs).run(
                overwrite_output=True
            )
            logger.success(f"Video created at {out_vid_path}")
    finally:
        if drawtext_file:
            os.unlink(drawtext_file)

    return frames


@app.command()
def extract_specific_frames(
    input_path: str,
    timestamps_or_frames: list[str] = typer.Option(),
    max_short_edge: int = 1080,
    as_timestamps: bool = True,
    output_dir: Optional[str] = None,
):
    """
    Extract specific frames from a video file using FFmpeg at given timestamps or frame numbers.

    Args:
        input_path (str): Path to the input video file.
        timestamps_or_frames (list): List of timestamps (in seconds) or frame numbers to extract.
        max_short_edge (int): Maximum length of the shorter edge of the extracted frames.
        as_timestamps (bool): If True, treat input list as timestamps. If False, treat as frame numbers.
        output_dir (str): Directory to save the extracted frames as ``{vname}_{target}.jpg``.
            If None, frames are only returned in memory.

    Returns:
        List of PIL Images corresponding to the specified timestamps/frames
    """
    if output_dir:
        assert os.path.isdir(
            output_dir
        ), f"Output directory {output_dir} does not exist"
    vname, _ = os.path.splitext(os.path.basename(input_path))
    # Probe video to get width, height, and duration
    vmeta = get_video_metadata(input_path, bverbose=False)
    org_w, org_h = vmeta["width"], vmeta["height"]
    max_short_edge = int(max_short_edge) if max_short_edge else min(org_w, org_h)
    long_edge = int((max(org_h, org_w) / min(org_h, org_w)) * max_short_edge)
    long_edge += 0 if long_edge % 2 == 0 else 1
    duration = vmeta["duration"]
    org_fps = vmeta["fps"]

    # add scale filter only if needed
    add_scale_filter = max_short_edge < min(org_w, org_h)
    w = max_short_edge if org_w < org_h else long_edge
    h = max_short_edge if org_w > org_h else long_edge
    logger.debug(f"Video dimensions: {org_w}x{org_h}")
    if add_scale_filter:
        logger.debug(f"\tscaling video to {w}x{h}")
    scale_filter = f",scale='{w}:{h}'" if add_scale_filter else ""

    frames = []

    for target in tqdm(timestamps_or_frames, desc="Extracting specific frames"):
        try:
            # Convert frame number to timestamp if needed
            if as_timestamps:
                seek_time = float(target)
                if seek_time > duration:
                    logger.warning(
                        f"Timestamp {seek_time}s exceeds video duration {duration}s, skipping"
                    )
                    frames.append(None)  # keep list index-aligned with input
                    continue
            else:
                # Convert frame number to timestamp
                seek_time = float(target) / org_fps
                if seek_time > duration:
                    logger.warning(f"Frame {target} exceeds video duration, skipping")
                    frames.append(None)  # keep list index-aligned with input
                    continue

            filter_chain = f"fps={org_fps}{scale_filter}"

            # Extract single frame at specific timestamp.
            # NOTE: -ss is passed as an input option (before -i), which is a fast
            # seek that snaps to the nearest keyframe rather than the exact frame.
            # In frame-number mode this means the returned frame may be off by a
            # few frames. Move ss to an output option (after .input()) for
            # exact-but-slower seeking if precise frames are ever required.
            # stderr left to inherit (not piped) to avoid a pipe-buffer
            # deadlock while we only read stdout — see extract_frames.
            process = (
                ffmpeg.input(input_path, ss=seek_time)
                .output(
                    "pipe:",
                    vf=filter_chain,
                    format="rawvideo",
                    pix_fmt="rgb24",
                    frames=1,
                )
                .run_async(pipe_stdout=True)
            )

            frame_size = (
                w * h * 3 if add_scale_filter else org_w * org_h * 3
            )  # 3 bytes per pixel (RGB)

            in_bytes = process.stdout.read(frame_size)
            if in_bytes and len(in_bytes) >= frame_size:
                frame = Image.frombytes(
                    "RGB", (w, h) if add_scale_filter else (org_w, org_h), in_bytes
                )
                frames.append(frame)
                if output_dir:
                    frame.save(os.path.join(output_dir, f"{vname}_{target}.jpg"))
            else:
                logger.warning(
                    f"Failed to extract frame at {'timestamp' if as_timestamps else 'frame'} {target}"
                )
                frames.append(
                    None
                )  # Add None for failed extractions to maintain list alignment

            process.stdout.close()
            process.wait()

        except Exception as e:
            logger.error(
                f"Error extracting frame at {'timestamp' if as_timestamps else 'frame'} {target}: {e}"
            )
            frames.append(None)  # Add None for failed extractions

    # Filter out None values if desired (or keep them for alignment)
    logger.info(
        f"Successfully extracted {len([f for f in frames if f is not None])} out of {len(timestamps_or_frames)} requested frames"
    )

    return frames


def frames_to_video(
    frames,
    out_path: str,
    fps: float,
    *,
    vcodec: str = "libx264",
    pix_fmt: str = "yuv420p",
):
    """Encode a list of PIL frames into a (silent) video file via FFmpeg.

    RGB frames are piped to ffmpeg's stdin as ``rawvideo`` and encoded. All
    frames must share the size of ``frames[0]``. The inverse of
    :func:`extract_frames` — used to write annotated frames back out.

    Args:
        frames: Non-empty list of same-size ``PIL.Image.Image`` (converted to RGB).
        out_path (str): Destination video path (overwritten if it exists).
        fps (float): Output frame rate.
        vcodec (str): Video codec (default ``libx264``).
        pix_fmt (str): Output pixel format (default ``yuv420p``).

    Returns:
        str: ``out_path``.

    Raises:
        ValueError: If ``frames`` is empty.
    """
    if not frames:
        raise ValueError("frames_to_video: no frames to encode")
    w, h = frames[0].size
    # Only stdin is piped (we feed frames); stdout/stderr inherit, so there's no
    # pipe-buffer deadlock. yuv420p needs even dimensions — scale down to even.
    process = (
        ffmpeg.input("pipe:", format="rawvideo", pix_fmt="rgb24", s=f"{w}x{h}", r=fps)
        .output(
            out_path,
            vcodec=vcodec,
            pix_fmt=pix_fmt,
            r=fps,
            vf="scale=trunc(iw/2)*2:trunc(ih/2)*2",
        )
        .overwrite_output()
        .run_async(pipe_stdin=True)
    )
    for frame in tqdm(frames, desc=f"Encoding {out_path}"):
        process.stdin.write(frame.convert("RGB").tobytes())
    process.stdin.close()
    process.wait()
    logger.success(f"Video created at {out_path} ({len(frames)} frames @ {fps}fps)")
    return out_path


@app.command()
def extract_audio(
    video_path: str,
    output_dir: Optional[str] = None,
    overwrite: bool = False,
    lossless: bool = False,
):
    """Extract the audio track of a video file.

    By default the audio is re-encoded to mp3. Set ``lossless=True`` to copy the
    original audio stream without re-encoding into an m4a container.

    Args:
        video_path (str): Path to the input video file.
        output_dir (str): Directory to save the audio under. Defaults to the
            video's own directory when None. Output is written to
            ``{output_dir}/{vname}/{vname}.{ext}``.
        overwrite (bool): Overwrite the output if it already exists.
        lossless (bool): If True, copy the audio stream (acodec="copy") into an
            m4a file instead of re-encoding to mp3.

    Returns:
        str | None: Path to the extracted audio file, or None on failure / no audio.
    """
    # only return audio if its available
    vmeta = get_video_metadata(video_path, bverbose=False)
    if vmeta.get("audio_codec") == "none":
        logger.error(f"No audio found in {video_path}")
        return None

    # Create output directory if it doesn't exist
    output_dir = output_dir if output_dir else os.path.dirname(video_path)
    vname, vext = os.path.splitext(os.path.basename(video_path))
    output_dir = os.path.join(output_dir, vname)
    out_ext = "m4a" if lossless else "mp3"
    output_fname = os.path.join(output_dir, f"{vname}.{out_ext}")
    if os.path.isfile(output_fname):
        if overwrite:
            os.remove(output_fname)
            logger.warning(f"removed existing data: {output_fname}")
        else:
            logger.error(f"overwrite is false and data already exists: {output_fname}")
            return None
    os.makedirs(output_dir, exist_ok=True)

    # Construct the ffmpeg-python pipeline
    stream = ffmpeg.input(video_path)
    config_dict = {"map": "0:a", "acodec": "copy" if lossless else "mp3"}
    stream = ffmpeg.output(stream, output_fname, **config_dict)

    # Execute the ffmpeg command
    try:
        ffmpeg.run(stream, capture_stdout=True, capture_stderr=True)
        logger.success(f"audio extracted to {output_fname}")
        return output_fname
    except ffmpeg.Error as e:
        logger.error(f"Error executing FFmpeg command: {e.stderr.decode()}")
    return None


if __name__ == "__main__":
    app()