# -*- coding: utf-8 -*-
"""Persistent task state store for meeting-style offline jobs."""

from __future__ import annotations

import json
import time
from pathlib import Path
from threading import RLock
from typing import Any, Optional

from app.core.config import settings

tasks_db: dict[str, dict[str, Any]] = {}
_tasks_lock = RLock()
_last_cleanup_at = 0


def _task_state_dir() -> Path:
    return Path(settings.TASK_STATE_DIR)


def _task_file_path(task_id: str) -> Path:
    return _task_state_dir() / f"{task_id}.json"


def _task_result_file_path(task_id: str) -> Path:
    return _task_state_dir() / f"{task_id}.result.json"


def _retention_seconds() -> int:
    return max(0, int(settings.TASK_RETENTION_HOURS)) * 3600


def _is_task_expired(task_payload: dict[str, Any], now_ts: Optional[int] = None) -> bool:
    retention_seconds = _retention_seconds()
    if retention_seconds <= 0:
        return False
    current_time = int(now_ts or time.time())
    base_timestamp = int(task_payload.get("updated_at") or task_payload.get("created_at") or 0)
    if base_timestamp <= 0:
        return False
    return current_time - base_timestamp >= retention_seconds


def _write_json_file(file_path: Path, payload: dict[str, Any]) -> None:
    file_path.parent.mkdir(parents=True, exist_ok=True)
    temporary_file_path = file_path.with_suffix(f"{file_path.suffix}.tmp")
    temporary_file_path.write_text(
        json.dumps(payload, ensure_ascii=False),
        encoding="utf-8",
    )
    temporary_file_path.replace(file_path)


def _write_task_file(task_id: str, payload: dict[str, Any]) -> None:
    _write_json_file(_task_file_path(task_id), payload)


def _remove_task_file(task_id: str) -> None:
    task_file_path = _task_file_path(task_id)
    if task_file_path.exists():
        task_file_path.unlink()


def _write_task_result_file(task_id: str, payload: dict[str, Any]) -> None:
    _write_json_file(_task_result_file_path(task_id), payload)


def _remove_task_result_file(task_id: str) -> None:
    task_result_file_path = _task_result_file_path(task_id)
    if task_result_file_path.exists():
        task_result_file_path.unlink()


def _load_task_payload_from_file(task_file_path: Path) -> Optional[tuple[str, dict[str, Any]]]:
    try:
        payload = json.loads(task_file_path.read_text(encoding="utf-8"))
    except Exception:
        return None
    if not isinstance(payload, dict):
        return None
    task_id = str(payload.get("task_id") or task_file_path.stem).strip()
    if not task_id:
        return None
    payload["task_id"] = task_id
    return task_id, payload


def _load_task_result_payload(task_id: str) -> Optional[dict[str, Any]]:
    task_result_file_path = _task_result_file_path(task_id)
    if not task_result_file_path.exists():
        return None
    try:
        payload = json.loads(task_result_file_path.read_text(encoding="utf-8"))
    except Exception:
        return None
    if not isinstance(payload, dict):
        return None
    return payload


def _split_task_payload(task_id: str, payload: dict[str, Any], *, persist_legacy_result: bool = False) -> tuple[dict[str, Any], bool]:
    status_payload = dict(payload)
    has_result = "result" in status_payload
    result_payload = status_payload.pop("result", None)
    if has_result:
        if isinstance(result_payload, dict):
            _write_task_result_file(task_id, result_payload)
        elif result_payload is None:
            _remove_task_result_file(task_id)
        if persist_legacy_result:
            _write_task_file(task_id, status_payload)
    return status_payload, has_result


def _status_file_paths() -> list[Path]:
    return [
        task_file_path
        for task_file_path in _task_state_dir().glob("*.json")
        if not task_file_path.name.endswith(".result.json")
    ]


def load_tasks_from_disk() -> None:
    with _tasks_lock:
        tasks_db.clear()
        task_directory = _task_state_dir()
        task_directory.mkdir(parents=True, exist_ok=True)
        current_time = int(time.time())
        for task_file_path in _status_file_paths():
            loaded_item = _load_task_payload_from_file(task_file_path)
            if loaded_item is None:
                try:
                    task_file_path.unlink()
                except Exception:
                    pass
                continue
            task_id, payload = loaded_item
            payload, _ = _split_task_payload(task_id, payload, persist_legacy_result=True)
            if _is_task_expired(payload, now_ts=current_time):
                try:
                    task_file_path.unlink()
                except Exception:
                    pass
                try:
                    _remove_task_result_file(task_id)
                except Exception:
                    pass
                continue
            tasks_db[task_id] = payload


def cleanup_expired_tasks(force: bool = False) -> None:
    global _last_cleanup_at
    current_time = int(time.time())
    if not force and current_time - _last_cleanup_at < 60:
        return
    with _tasks_lock:
        expired_task_ids = [
            task_id
            for task_id, task_payload in tasks_db.items()
            if _is_task_expired(task_payload, now_ts=current_time)
        ]
        for task_id in expired_task_ids:
            tasks_db.pop(task_id, None)
            try:
                _remove_task_file(task_id)
            except Exception:
                pass
            try:
                _remove_task_result_file(task_id)
            except Exception:
                pass
        for task_file_path in _status_file_paths():
            loaded_item = _load_task_payload_from_file(task_file_path)
            if loaded_item is None:
                try:
                    task_file_path.unlink()
                except Exception:
                    pass
                continue
            task_id, payload = loaded_item
            payload, _ = _split_task_payload(task_id, payload, persist_legacy_result=True)
            if _is_task_expired(payload, now_ts=current_time):
                try:
                    task_file_path.unlink()
                except Exception:
                    pass
                try:
                    _remove_task_result_file(task_id)
                except Exception:
                    pass
        _last_cleanup_at = current_time


def recover_tasks_after_restart() -> None:
    load_tasks_from_disk()
    cleanup_expired_tasks(force=True)
    with _tasks_lock:
        for task_id, task_payload in list(tasks_db.items()):
            if str(task_payload.get("status") or "").strip() not in {"queued", "processing"}:
                continue
            interrupted_message = "服务已重启，原离线任务已中断，请重新提交。"
            task_payload.update(
                {
                    "status": "failed",
                    "stage": "failed",
                    "message": interrupted_message,
                    "error": interrupted_message,
                    "percentage": 100,
                    "updated_at": int(time.time()),
                }
            )
            tasks_db[task_id] = task_payload
            _write_task_file(task_id, task_payload)


def create_task_record(task_id: str, payload: dict[str, Any]) -> dict[str, Any]:
    current_time = int(time.time())
    task_payload = dict(payload)
    task_payload["task_id"] = task_id
    task_payload.setdefault("created_at", current_time)
    task_payload["updated_at"] = current_time
    status_payload, has_result = _split_task_payload(task_id, task_payload)
    with _tasks_lock:
        tasks_db[task_id] = status_payload
        _write_task_file(task_id, status_payload)
    response_payload = dict(status_payload)
    if has_result:
        response_payload["result"] = _load_task_result_payload(task_id)
    return response_payload


def get_task_record(task_id: str, *, include_result: bool = False) -> Optional[dict[str, Any]]:
    with _tasks_lock:
        task_file_path = _task_file_path(task_id)
        if task_file_path.exists():
            loaded_item = _load_task_payload_from_file(task_file_path)
            if loaded_item is None:
                return None
            loaded_task_id, task_payload = loaded_item
            task_payload, _ = _split_task_payload(
                loaded_task_id,
                task_payload,
                persist_legacy_result=True,
            )
            if loaded_task_id != task_id or _is_task_expired(task_payload):
                return None
            tasks_db[task_id] = task_payload
        else:
            task_payload = tasks_db.get(task_id)
            if task_payload is None:
                return None
        response_payload = dict(task_payload)
        if include_result:
            result_payload = _load_task_result_payload(task_id)
            if result_payload is not None:
                response_payload["result"] = result_payload
        return response_payload


def update_task_record(task_id: str, payload: dict[str, Any]) -> dict[str, Any]:
    current_time = int(time.time())
    with _tasks_lock:
        task_payload = dict(tasks_db.get(task_id) or {})
        task_payload.update(payload)
        task_payload["task_id"] = task_id
        task_payload.setdefault("created_at", current_time)
        task_payload["updated_at"] = current_time
        status_payload, has_result = _split_task_payload(task_id, task_payload)
        tasks_db[task_id] = status_payload
        _write_task_file(task_id, status_payload)
        response_payload = dict(status_payload)
        if has_result:
            response_payload["result"] = _load_task_result_payload(task_id)
        return response_payload


load_tasks_from_disk()