from __future__ import annotations

import json
import os
import subprocess
import sys
import tempfile
from datetime import datetime, timezone
from pathlib import Path

from app.settings import Settings
from app.state import HealthSnapshot

BEHAVIOR_EN_TO_ZH = {
    "feeding": "吃饵",
    "normal": "正常游行",
    "scared": "惊吓",
}


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


def behavior_to_health(behavior_en: str) -> str:
    if behavior_en == "scared":
        return "不健康"
    return "健康"


def run_action_subprocess(mp4_path: Path, settings: Settings) -> str:
    script = settings.fish_action_root / "predict_video_x3d_3class.py"
    if not script.is_file():
        raise FileNotFoundError(f"Missing FishAction script: {script}")

    mp4_path = mp4_path.resolve()
    path_prefix = str(mp4_path.parent)
    rel_name = mp4_path.name

    with tempfile.NamedTemporaryFile(
        mode="w", suffix=".csv", delete=False, encoding="utf-8"
    ) as tmp:
        tmp.write(f"{rel_name} 0\n")
        csv_path = tmp.name

    out_fd, out_json = tempfile.mkstemp(suffix="_pred.json")
    os.close(out_fd)

    try:
        cmd = [
            _py_exe(settings),
            str(script),
            "--checkpoint",
            settings.action_checkpoint,
            "--csv",
            csv_path,
            "--path_prefix",
            path_prefix,
            "--clips_per_video",
            str(settings.action_clips_per_video),
            "--batch_size",
            str(settings.action_batch_size),
            "--num_workers",
            str(settings.action_num_workers),
            "--output_json",
            out_json,
            "--log_interval",
            "0",
        ]
        proc = subprocess.run(
            cmd,
            cwd=str(settings.fish_action_root),
            env=os.environ.copy(),
            capture_output=True,
            text=True,
        )
        if proc.returncode != 0:
            err = (proc.stderr or "") + (proc.stdout or "")
            raise RuntimeError(
                f"predict_video_x3d_3class.py failed ({proc.returncode}): {err[-4000:]}"
            )
        if not Path(out_json).is_file():
            raise RuntimeError(f"No output_json written: {out_json}")
        with open(out_json, encoding="utf-8") as f:
            rows = json.load(f)
        if not rows:
            raise RuntimeError("Empty prediction JSON")
        pred_en = str(rows[0].get("pred_3class", "")).strip().lower()
        if pred_en not in BEHAVIOR_EN_TO_ZH:
            raise RuntimeError(f"Unexpected pred_3class: {pred_en!r}")
        return pred_en
    finally:
        Path(csv_path).unlink(missing_ok=True)
        Path(out_json).unlink(missing_ok=True)


def run_full_action(mp4_path: Path, settings: Settings) -> HealthSnapshot:
    pred_en = run_action_subprocess(mp4_path, settings)
    zh = BEHAVIOR_EN_TO_ZH[pred_en]
    health = behavior_to_health(pred_en)
    return HealthSnapshot(
        behavior_result=zh,
        health_result=health,
        updated_at=datetime.now(timezone.utc),
        raw_class_en=pred_en,
    )