from __future__ import annotations

import json
import math
import os
import re
import shutil
import subprocess
import sys
from datetime import datetime, timezone
from pathlib import Path
from typing import Any, Dict, List, Optional, Tuple

from app.logging_config import format_json_pretty
from app.settings import Settings
from app.state import MeasureSnapshot
from app.subprocess_run import run_subprocess_with_log
from loguru import logger


def _py_exe(settings: Settings) -> str:
    return settings.python_fish_measure or sys.executable


def _predict_weigth_from_svo2_extra_args(settings: Settings) -> List[str]:
    """Flags aligned with FishMeasure/predict_weigth_from_svo2.py CLI."""
    out: List[str] = []
    if settings.predict_filter_pointcloud:
        out.append("--filter-pointcloud")
    if settings.predict_use_density_filter:
        out.append("--use-density-filter")
    if settings.predict_use_clustering_filter:
        out.append("--use-clustering-filter")
    if (
        settings.predict_use_pointcloud_classifier
        and settings.predict_pointcloud_classifier
        and Path(settings.predict_pointcloud_classifier).is_file()
    ):
        out.extend(
            [
                "--pointcloud-classifier",
                settings.predict_pointcloud_classifier,
                "--use-pointcloud-classifier",
                "--pointcloud-classifier-threshold",
                str(settings.predict_pointcloud_classifier_threshold),
            ]
        )
    if settings.predict_use_flatness_filter:
        out.append("--use-flatness-filter")
        out.extend(["--flatness-threshold", str(settings.predict_flatness_threshold)])
    out.extend(["--weight-top-k", str(settings.measure_weight_top_k)])
    if settings.measure_weight_top_by_length:
        out.append("--weight-top-by-length")
    else:
        out.append("--no-weight-top-by-length")
    if settings.predict_fish_video_weight_overlay:
        out.extend(
            [
                "--fish-video-weight-overlay",
                "--minute-interval-sec",
                str(settings.predict_minute_interval_sec),
            ]
        )
    if not settings.measure_reuse_existing_clouds:
        out.append("--no-reuse-existing-clouds")
    return out


def run_measure_subprocess(svo_path: Path, settings: Settings) -> None:
    script = settings.fish_measure_root / "predict_weigth_from_svo2.py"
    if not script.is_file():
        raise FileNotFoundError(f"Missing FishMeasure script: {script}")

    settings.measure_output_root.mkdir(parents=True, exist_ok=True)

    cmd = [
        _py_exe(settings),
        str(script),
        "--svo",
        str(svo_path.resolve()),
        "--save-output",
        str(settings.measure_output_root.resolve()),
        "--yolo-model",
        settings.yolo_model,
        "--weight-checkpoint",
        settings.weight_checkpoint,
        "--conf",
        str(settings.predict_conf),
        "--imgsz",
        str(settings.predict_imgsz),
        "--sam-device",
        settings.sam_device,
        "--max-frames",
        str(settings.predict_max_frames),
        "--frame-stride",
        str(settings.predict_frame_stride),
    ]
    cmd.extend(_predict_weigth_from_svo2_extra_args(settings))

    proc = run_subprocess_with_log(
        cmd,
        cwd=str(settings.fish_measure_root),
        env=os.environ.copy(),
        log_name="FishMeasure",
    )
    if proc.returncode != 0:
        err = proc.stdout or ""
        raise RuntimeError(
            f"predict_weigth_from_svo2.py failed ({proc.returncode}): {err[-4000:]}"
        )


def _summary_entry_matches_svo(item: Dict[str, Any], svo_path: Path) -> bool:
    stem = svo_path.stem
    resolved = str(svo_path.resolve())
    svo_key = item.get("svo")
    if svo_key:
        try:
            if Path(str(svo_key)).resolve() == svo_path.resolve():
                return True
        except OSError:
            pass
        if str(svo_key) == resolved:
            return True
    if item.get("svo_name") == stem:
        return True
    return False


def _load_weight_json(svo_path: Path, settings: Settings) -> Dict[str, Any]:
    """读取 FishMeasure 合并结果。优先 per-SVO 的 weight_prediction.json；否则从 weight_predictions_summary.json 取匹配项（predict 脚本在权重步失败时仍 exit 0 只写 summary）。"""
    stem = svo_path.stem
    root = settings.measure_output_root
    candidate = root / stem / "weight_prediction.json"
    if candidate.is_file():
        with open(candidate, encoding="utf-8") as f:
            return json.load(f)

    summary_path = root / "weight_predictions_summary.json"
    if summary_path.is_file():
        with open(summary_path, encoding="utf-8") as f:
            summary_list: Any = json.load(f)
        if isinstance(summary_list, list):
            for item in reversed(summary_list):
                if not isinstance(item, dict):
                    continue
                if not _summary_entry_matches_svo(item, svo_path):
                    continue
                err = item.get("error")
                if err:
                    raise RuntimeError(
                        f"FishMeasure 权重步骤失败（{svo_path.name}）: {err}"
                    )
                if item.get("per_cloud") or item.get("per_file") or item.get(
                    "dgcnn_summary"
                ):
                    return item
                break

    combined_path = root / "weight_prediction.json"
    if combined_path.is_file():
        with open(combined_path, encoding="utf-8") as f:
            combined: Any = json.load(f)
        if isinstance(combined, dict) and combined.get("combined"):
            names = combined.get("svo_names") or []
            if stem in names:
                return combined

    raise FileNotFoundError(
        f"未找到测量结果 JSON：{candidate}（且 summary 中无本条 SVO 的成功记录）"
    )


_TID_RE = re.compile(r"_tid(\d+)")


def _parse_tid_from_ply_name(name: str) -> Optional[int]:
    """与 FishMeasure/fish_video_weight_evaluation._parse_tid_from_ply_name 一致。"""
    m = _TID_RE.search(name)
    return int(m.group(1)) if m else None


def _safe_media_prefix(stem: str) -> str:
    s = re.sub(r"[^\w.\-]+", "_", stem, flags=re.UNICODE).strip("._") or "svo"
    return s[:120]


def _result_from_weight_prediction(data: Dict[str, Any]) -> List[Dict[str, Any]]:
    """按 track_id 聚合：体重取 max(predicted_weight_g)，体长取达到 max 的那条 PLY 的 length_input (mm)。"""
    items = data.get("per_cloud") or data.get("per_file") or []
    if not isinstance(items, list):
        return []
    # tid -> (max_weight_g, length_mm at max weight)
    best: Dict[int, Tuple[float, float]] = {}
    for it in items:
        if not isinstance(it, dict):
            continue
        ply = it.get("ply")
        if not ply:
            continue
        tid = _parse_tid_from_ply_name(Path(str(ply)).name)
        if tid is None:
            continue
        try:
            wg = float(it.get("predicted_weight_g", float("nan")))
        except (TypeError, ValueError):
            continue
        if not math.isfinite(wg):
            continue
        try:
            ln = float(it.get("length_input", float("nan")))
        except (TypeError, ValueError):
            ln = float("nan")
        if tid not in best or wg > best[tid][0]:
            best[tid] = (wg, ln)
    out: List[Dict[str, Any]] = []
    for tid in sorted(best.keys()):
        wg, ln = best[tid]
        if not math.isfinite(ln):
            continue
        out.append({"id": tid, "weight": wg, "length": ln})
    return out


def _find_preview_videos(output_dir: Path) -> Tuple[Optional[Path], Optional[Path]]:
    previews = sorted(output_dir.rglob("*preview*.mp4"))
    if len(previews) >= 2:
        return previews[0], previews[1]
    all_mp4 = sorted(output_dir.rglob("*.mp4"))
    if len(all_mp4) >= 2:
        return all_mp4[0], all_mp4[1]
    if len(all_mp4) == 1:
        return all_mp4[0], all_mp4[0]
    if len(previews) == 1:
        return previews[0], previews[0]
    return None, None


def _split_sbs_video(src: Path, left_dst: Path, right_dst: Path) -> bool:
    """Split a side-by-side stereo video (W x H where W == 2*H_single) into left/right halves.

    Returns True if split succeeded, False otherwise (caller should fall back to copy).
    """
    ffmpeg_path = _get_ffmpeg_path()
    ffprobe_path = str(Path(ffmpeg_path).parent / "ffprobe")
    probe = subprocess.run(
        [
            ffprobe_path, "-v", "quiet", "-print_format", "json",
            "-show_streams", str(src),
        ],
        capture_output=True, text=True,
    )
    if probe.returncode != 0:
        return False
    import json as _json
    try:
        streams = _json.loads(probe.stdout).get("streams", [])
        vstream = next((s for s in streams if s.get("codec_type") == "video"), None)
        if vstream is None:
            return False
        w, h = int(vstream["width"]), int(vstream["height"])
    except Exception:
        return False
    half_w = w // 2
    if half_w < 1 or w < h:
        return False

    encoder, encoder_options, _ = _get_h264_encoder()
    for crop, dst in [
        (f"crop={half_w}:{h}:{half_w}:0", left_dst),
        (f"crop={half_w}:{h}:0:0", right_dst),
    ]:
        cmd = [ffmpeg_path, "-y", "-i", str(src), "-vf", crop, "-an"]
        if encoder:
            cmd.extend(["-c:v", encoder, "-pix_fmt", "yuv420p", "-movflags", "+faststart"])
            cmd.extend(encoder_options)
        else:
            cmd.extend(["-q:v", "5"])
        cmd.append(str(dst))
        r = subprocess.run(cmd, capture_output=True, text=True)
        if r.returncode != 0:
            return False
    return True


def _get_ffmpeg_path() -> str:
    """获取可用的 ffmpeg 路径。优先使用项目配置的 ffmpeg。"""
    # 优先使用项目目录下的 ffmpeg
    project_ffmpeg = Path("/home/ubuntu/projects/FishServer/tools/ffmpeg/bin/ffmpeg")
    if project_ffmpeg.is_file():
        return str(project_ffmpeg)
    # 尝试系统路径
    system_paths = ["/usr/bin/ffmpeg", "/usr/local/bin/ffmpeg"]
    for path in system_paths:
        if Path(path).is_file():
            return path
    # 回退到 PATH 中的 ffmpeg
    return "ffmpeg"


def _get_h264_encoder() -> tuple[str, list[str], str]:
    """检测可用的H.264编码器，返回 (encoder_name, options, ffmpeg_path)。

    优先使用 libx264（纯软件，最可靠），硬件编码器需要实际测试才能确认可用。
    """
    encoders_to_try = [
        ("libx264", ["-preset", "fast", "-crf", "23"]),
        ("h264_nvenc", ["-preset", "fast"]),
        ("libopenh264", []),
    ]

    ffmpeg_path = _get_ffmpeg_path()
    try:
        result = subprocess.run(
            [ffmpeg_path, "-encoders"],
            capture_output=True, text=True, timeout=10
        )
        encoders_output = result.stdout
        for encoder, options in encoders_to_try:
            if encoder in encoders_output:
                return encoder, options, ffmpeg_path
    except Exception:
        pass
    return "", [], ffmpeg_path


def _get_x264_path() -> Optional[str]:
    """检测系统上是否有可用的 x264 命令行工具。"""
    for path in ["/usr/bin/x264", "/usr/local/bin/x264", "x264"]:
        if path == "x264":
            try:
                result = subprocess.run(["which", "x264"], capture_output=True, text=True, timeout=5)
                if result.returncode == 0 and result.stdout.strip():
                    return result.stdout.strip()
            except Exception:
                pass
        elif Path(path).is_file():
            return path
    return None


def _transcode_with_x264(src: Path, dst: Path) -> bool:
    """使用 x264 命令行工具将视频转码为 H.264。

    这是当 ffmpeg 的 H.264 编码器都不可用时（如 libopenh264 版本不匹配）的最后备选方案。
    通过 ffmpeg 提取原始 YUV 帧，然后用 x264 编码。
    """
    import tempfile
    import shutil

    x264_path = _get_x264_path()
    ffmpeg_path = _get_ffmpeg_path()

    if not x264_path:
        logger.debug("[FishMeasure] x264 not available")
        return False

    # 首先用 ffprobe 获取视频信息
    try:
        probe = subprocess.run(
            ["ffprobe", "-v", "quiet", "-print_format", "json", "-show_streams", str(src)],
            capture_output=True, text=True, timeout=10
        )
        import json as _json
        streams = _json.loads(probe.stdout).get("streams", [])
        vstream = next((s for s in streams if s.get("codec_type") == "video"), None)
        if not vstream:
            return False
        width = int(vstream["width"])
        height = int(vstream["height"])
        fps_str = vstream.get("r_frame_rate", "25/1")
        # 解析 fps (可能是 "30/1" 或 "30000/1001" 格式)
        if "/" in fps_str:
            num, den = map(int, fps_str.split("/"))
            fps = num / den if den != 0 else 25.0
        else:
            fps = float(fps_str)
    except Exception as e:
        logger.debug("[FishMeasure] x264 probe failed: {}", str(e))
        return False

    tmp_yuv = None
    try:
        # 创建临时 YUV 文件
        with tempfile.NamedTemporaryFile(suffix=".yuv", delete=False) as f:
            tmp_yuv = Path(f.name)

        # 步骤1: 用 ffmpeg 提取 YUV 原始帧
        extract_cmd = [
            ffmpeg_path, "-y", "-i", str(src),
            "-f", "rawvideo",
            "-pix_fmt", "yuv420p",
            str(tmp_yuv)
        ]
        result = subprocess.run(extract_cmd, capture_output=True, text=True, timeout=300)
        if result.returncode != 0:
            logger.debug("[FishMeasure] x264: YUV extraction failed: {}", result.stderr[-200:] if result.stderr else "unknown")
            return False

        # 步骤2: 用 x264 编码
        # x264 需要特定格式的输入参数
        encode_cmd = [
            x264_path,
            "--input-res", f"{width}x{height}",
            "--fps", str(fps),
            "--preset", "fast",
            "--crf", "23",
            "--output-csp", "i420",
            "-o", str(dst),
            str(tmp_yuv)
        ]
        result = subprocess.run(encode_cmd, capture_output=True, text=True, timeout=600)

        if result.returncode == 0 and dst.is_file():
            logger.info("[FishMeasure] x264 transcoding SUCCESS: {} ({} bytes)", dst.name, dst.stat().st_size)
            return True
        else:
            stderr = result.stderr[-300:] if result.stderr else "Unknown error"
            logger.warning("[FishMeasure] x264 transcoding FAILED: {}", stderr)
            if dst.exists():
                dst.unlink()
            return False
    except Exception as e:
        logger.warning("[FishMeasure] x264 transcoding exception: {}", str(e))
        if dst.exists():
            dst.unlink()
        return False
    finally:
        if tmp_yuv and tmp_yuv.exists():
            tmp_yuv.unlink()


def _transcode_fallback(src: Path, dst: Path) -> bool:
    """备选转码方案：提取帧为图像序列，然后用ffmpeg编码为H.264。

    这种方法避免编码器直接读取 mp4v 文件的兼容性问题。
    """
    import tempfile
    import shutil

    encoder, encoder_options, ffmpeg_path = _get_h264_encoder()
    if not encoder:
        return False

    tmp_dir = tempfile.mkdtemp()
    try:
        # 步骤1: 提取帧为 jpg 序列
        frames_pattern = f"{tmp_dir}/frame_%04d.jpg"
        extract_cmd = [
            ffmpeg_path, "-y", "-i", str(src),
            "-q:v", "2",  # 高质量
            frames_pattern
        ]
        result = subprocess.run(extract_cmd, capture_output=True, text=True, timeout=60)
        if result.returncode != 0:
            logger.debug("[FishMeasure] Fallback: frame extraction failed: {}", result.stderr[-200:] if result.stderr else "unknown")
            return False

        # 步骤2: 从帧编码为 H.264 MP4
        encode_cmd = [
            ffmpeg_path, "-y",
            "-i", frames_pattern,
            "-c:v", encoder,
            "-pix_fmt", "yuv420p",
            "-movflags", "+faststart",
            "-an",
        ]
        encode_cmd.extend(encoder_options)
        encode_cmd.append(str(dst))

        result = subprocess.run(encode_cmd, capture_output=True, text=True, timeout=120)

        if result.returncode == 0 and dst.is_file():
            logger.info("[FishMeasure] Fallback transcoding SUCCESS: {} ({} bytes)", dst.name, dst.stat().st_size)
            return True
        else:
            stderr = result.stderr[-300:] if result.stderr else "Unknown error"
            logger.warning("[FishMeasure] Fallback transcoding FAILED: {}", stderr)
            if dst.exists():
                dst.unlink()
            return False
    except Exception as e:
        logger.warning("[FishMeasure] Fallback transcoding exception: {}", str(e))
        if dst.exists():
            dst.unlink()
        return False
    finally:
        # 清理临时目录
        shutil.rmtree(tmp_dir, ignore_errors=True)


def _transcode_to_h264(src: Path, dst: Path) -> bool:
    """使用 ffmpeg 将视频转码为 H.264 (浏览器兼容格式)。

    尝试多种H.264编码器，包括软件编码和硬件加速编码。
    如果直接转码失败，依次尝试备选方案：
    1. 提取帧重新编码
    2. 使用 x264 命令行工具（当 ffmpeg 的 H.264 编码器都不可用时）
    """
    encoder, encoder_options, ffmpeg_path = _get_h264_encoder()

    # 如果有可用的 ffmpeg H.264 编码器，先尝试直接转码
    if encoder:
        try:
            # 基础参数
            cmd = [
                ffmpeg_path, "-y", "-i", str(src),
                "-c:v", encoder,
                "-pix_fmt", "yuv420p",  # 确保兼容性
                "-movflags", "+faststart",  # 优化网络播放（moov前置）
                "-an",  # 去除音频
            ]
            cmd.extend(encoder_options)
            cmd.append(str(dst))

            logger.info("[FishMeasure] Transcoding with {} using {}: {} -> {}", encoder, ffmpeg_path, src.name, dst.name)
            result = subprocess.run(
                cmd, capture_output=True, text=True, timeout=300
            )

            if result.returncode == 0 and dst.is_file():
                logger.info("[FishMeasure] Transcoding SUCCESS: {} ({} bytes)", dst.name, dst.stat().st_size)
                return True
            else:
                stderr = result.stderr[-500:] if result.stderr else "Unknown error"
                logger.warning("[FishMeasure] Direct transcoding FAILED, trying fallback: {}", stderr)
                # 尝试备选方案1: 提取帧重新编码
                if _transcode_fallback(src, dst):
                    return True
                # 备选方案1失败，尝试 x264
                logger.info("[FishMeasure] Fallback failed, trying x264...")
                return _transcode_with_x264(src, dst)
        except Exception as e:
            logger.warning("[FishMeasure] Transcoding exception: {}", str(e))
            if _transcode_fallback(src, dst):
                return True
            return _transcode_with_x264(src, dst)
    else:
        # 没有可用的 ffmpeg H.264 编码器，直接尝试 x264
        logger.warning("[FishMeasure] No H.264 encoder available in ffmpeg, trying x264...")
        return _transcode_with_x264(src, dst)


def _publish_media(
    left: Optional[Path],
    right: Optional[Path],
    settings: Settings,
    file_prefix: str,
) -> Tuple[str, str]:
    settings.media_root.mkdir(parents=True, exist_ok=True)
    safe_p = _safe_media_prefix(file_prefix)
    left_dst = settings.media_root / f"{safe_p}_left.mp4"
    right_dst = settings.media_root / f"{safe_p}_right.mp4"
    base = settings.public_base_url.rstrip("/")

    if left is not None and left == right and left.is_file():
        if _split_sbs_video(left, left_dst, right_dst):
            return (
                f"{base}/media/{left_dst.name}",
                f"{base}/media/{right_dst.name}",
            )

    def publish(src: Optional[Path], dst: Path) -> str:
        if src is None or not src.is_file():
            return ""
        # 尝试转码为 H.264，如果失败则直接复制原文件
        if _transcode_to_h264(src, dst):
            logger.info("[FishMeasure] transcoded to H.264: {} -> {}", src.name, dst.name)
        else:
            # 转码失败，直接复制原文件
            shutil.copy2(src, dst)
            logger.warning("[FishMeasure] copied without transcoding: {} -> {}", src.name, dst.name)
        return f"{base}/media/{dst.name}"

    vl = publish(left, left_dst)
    vr = publish(right, right_dst)
    return vl, vr


def build_measure_snapshot(svo_path: Path, settings: Settings) -> MeasureSnapshot:
    data = _load_weight_json(svo_path, settings)
    summary = data.get("dgcnn_summary") or data.get("weight_summary") or {}

    weight_g = summary.get("avg_predicted_weight_g")
    length_mm = summary.get("avg_length_input_topk")
    if weight_g is None:
        weight_g = data.get("avg_predicted_weight_g")
    if length_mm is None:
        length_mm = summary.get("avg_length_input") or data.get("avg_length_input")

    result: List[Dict[str, Any]] = []
    if weight_g is not None and length_mm is not None:
        try:
            w = float(weight_g)
            l = float(length_mm)
            if math.isfinite(w) and math.isfinite(l):
                result = [{"id": 1, "weight": w, "length": l}]
        except (TypeError, ValueError):
            pass

    logger.info(
        "[FishMeasure] parsed {}\navg_weight_g(top5)={} avg_length_mm(top5)={}\nresult:\n{}\ndgcnn_summary:\n{}",
        svo_path.name,
        weight_g,
        length_mm,
        format_json_pretty(result),
        format_json_pretty(summary if summary else {}),
    )

    out_dir = Path(data.get("output_dir", settings.measure_output_root / svo_path.stem))
    lv, rv = _find_preview_videos(out_dir)
    prefix = (
        f"{datetime.now(timezone.utc).strftime('%Y%m%dT%H%M%S')}_{svo_path.stem}"
    )
    v_left, v_right = _publish_media(lv, rv, settings, prefix)
    logger.info(
        "[FishMeasure] media preview_paths={} {} | published_left={} published_right={}",
        lv,
        rv,
        v_left or "(none)",
        v_right or "(none)",
    )

    return MeasureSnapshot(
        result=result,
        video_left=v_left,
        video_right=v_right,
        updated_at=datetime.now(timezone.utc),
        raw_prediction_path=str(
            settings.measure_output_root / svo_path.stem / "weight_prediction.json"
        ),
    )


def run_full_measure(svo_path: Path, settings: Settings) -> MeasureSnapshot:
    logger.info("[FishMeasure] start svo={}", svo_path.resolve())
    run_measure_subprocess(svo_path, settings)
    snap = build_measure_snapshot(svo_path, settings)
    logger.info("[FishMeasure] done svo={} result_len={}", svo_path.name, len(snap.result))
    return snap