"""视频切片工具：将长视频按固定时长切分为多个片段。"""

from __future__ import annotations

import subprocess
import tempfile
from pathlib import Path
from typing import List, Tuple

from loguru import logger


def _get_ffmpeg_path() -> str:
    """获取可用的 ffmpeg 路径。"""
    project_ffmpeg = Path("/home/ubuntu/projects/FishServer/tools/ffmpeg/bin/ffmpeg")
    if project_ffmpeg.is_file():
        return str(project_ffmpeg)
    system_paths = ["/usr/bin/ffmpeg", "/usr/local/bin/ffmpeg"]
    for path in system_paths:
        if Path(path).is_file():
            return path
    return "ffmpeg"


def _get_ffprobe_path() -> str:
    """获取可用的 ffprobe 路径。"""
    ffmpeg_path = Path(_get_ffmpeg_path())
    ffprobe = ffmpeg_path.parent / "ffprobe"
    if ffprobe.is_file():
        return str(ffprobe)
    return "ffprobe"


def get_video_duration(video_path: Path) -> float:
    """获取视频时长（秒）。"""
    ffprobe_path = _get_ffprobe_path()
    try:
        result = subprocess.run(
            [
                ffprobe_path,
                "-v", "error",
                "-show_entries", "format=duration",
                "-of", "default=noprint_wrappers=1:nokey=1",
                str(video_path),
            ],
            capture_output=True,
            text=True,
            timeout=30,
        )
        if result.returncode == 0:
            duration = float(result.stdout.strip())
            return duration
    except Exception as e:
        logger.warning("[video_slice] failed to get duration: {}", e)
    return 0.0


def slice_video(
    video_path: Path,
    slice_duration: float = 10.0,
    output_dir: Path | None = None,
) -> Tuple[List[Path], Path]:
    """将视频按固定时长切分为多个片段。

    Args:
        video_path: 源视频路径
        slice_duration: 每个切片的时长（秒），默认10秒
        output_dir: 输出目录，默认使用临时目录

    Returns:
        (切片文件列表, 输出目录路径)
    """
    duration = get_video_duration(video_path)
    if duration <= slice_duration:
        # 视频太短，无需切片
        return [video_path], video_path.parent

    if output_dir is None:
        output_dir = Path(tempfile.mkdtemp(prefix="video_slices_"))
    output_dir.mkdir(parents=True, exist_ok=True)

    ffmpeg_path = _get_ffmpeg_path()
    base_name = video_path.stem

    # 计算需要切多少片
    num_slices = int(duration / slice_duration)
    if duration % slice_duration > 1.0:  # 剩余超过1秒才多切一片
        num_slices += 1

    logger.info(
        "[video_slice] slicing {} ({}s) into {} slices of {}s each",
        video_path.name,
        duration,
        num_slices,
        slice_duration,
    )

    slice_files: List[Path] = []
    for i in range(num_slices):
        start_time = i * slice_duration
        slice_file = output_dir / f"{base_name}_slice_{i:03d}.mp4"

        # 使用 ffmpeg 切片，-c copy 快速复制，避免重新编码
        cmd = [
            ffmpeg_path,
            "-y",
            "-ss", str(start_time),
            "-t", str(slice_duration),
            "-i", str(video_path),
            "-c", "copy",
            "-avoid_negative_ts", "make_zero",
            str(slice_file),
        ]

        try:
            result = subprocess.run(
                cmd,
                capture_output=True,
                text=True,
                timeout=60,
            )
            if result.returncode == 0 and slice_file.is_file():
                slice_files.append(slice_file)
                logger.debug(
                    "[video_slice] created slice {}: {} (start={}s)",
                    i,
                    slice_file.name,
                    start_time,
                )
            else:
                logger.warning(
                    "[video_slice] failed to create slice {}: {}",
                    i,
                    result.stderr[-200:] if result.stderr else "unknown",
                )
        except Exception as e:
            logger.warning("[video_slice] exception creating slice {}: {}", i, e)

    if not slice_files:
        # 切片失败，返回原视频
        return [video_path], video_path.parent

    logger.info(
        "[video_slice] created {} slices for {}",
        len(slice_files),
        video_path.name,
    )
    return slice_files, output_dir