# data_manager.py (修复版)

import json
import uuid
from datetime import datetime
from typing import List, Dict, Optional

DATABASE_PATH = "database.json"


def _load_database(db_path: str = DATABASE_PATH) -> List[Dict]:
    """
    内部函数：从指定的JSON文件加载数据库。
    """
    try:
        # 修改点：这里使用传入的 db_path，而不是全局变量
        with open(db_path, "r", encoding="utf-8") as f:
            return json.load(f)
    except FileNotFoundError:
        return []


def _save_database(data: List[Dict], db_path: str = DATABASE_PATH) -> None:
    """
    内部函数：将数据保存到指定的JSON文件。
    """
    # 修改点：这里使用传入的 db_path
    with open(db_path, "w", encoding="utf-8") as f:
        json.dump(data, f, indent=4, ensure_ascii=False)


def get_all_items(db_path: str = DATABASE_PATH) -> List[Dict]:
    """
    读取并返回指定数据库中所有物品的元数据。
    """
    return _load_database(db_path=db_path)


def add_item(
    vec_id: int,
    description: str,
    location: str,
    category: str,
    image_filename: str,
    tags: List[str],
    contact: str,
    item_type: str,
    db_path: str = DATABASE_PATH,
) -> Dict:
    """
    向指定的数据库中添加一条新的物品记录。
    """
    # 这里之前报错，因为 _load_database 不接受参数。现在修好了。
    items = _load_database(db_path=db_path)

    new_item = {
        "id": str(uuid.uuid4()),
        "vec_id": vec_id,
        "description": description,
        "location": location,
        "category": category,
        "image_filename": image_filename,
        "timestamp": datetime.utcnow().isoformat() + "Z",
        "tags": tags,
        "contact": contact,
        "item_type": item_type,
    }

    items.append(new_item)
    
    # 这里之前也会报错，现在修好了。
    _save_database(items, db_path=db_path)

    return new_item


def filter_items(
    location: Optional[str] = None,
    category: Optional[str] = None,
    date_range_start: Optional[str] = None,
    date_range_end: Optional[str] = None,
    db_path: str = DATABASE_PATH,
) -> List[Dict]:
    """
    根据一个或多个筛选条件从指定数据库过滤物品。
    """
    items = _load_database(db_path=db_path)
    filtered_items = []

    start_date = (
        datetime.fromisoformat(date_range_start.replace("Z", "+00:00"))
        if date_range_start
        else None
    )
    end_date = (
        datetime.fromisoformat(date_range_end.replace("Z", "+00:00"))
        if date_range_end
        else None
    )

    for item in items:
        if location and item.get("location") != location:
            continue
        if category and item.get("category") != category:
            continue
        item_date = datetime.fromisoformat(item.get("timestamp").replace("Z", "+00:00"))
        if start_date and item_date < start_date:
            continue
        if end_date and item_date > end_date:
            continue
        filtered_items.append(item)

    return filtered_items


def get_item_by_vec_id(vec_id: int, db_path: str = DATABASE_PATH) -> Optional[Dict]:
    """
    通过vec_id从指定数据库快速查找对应的物品元数据。
    """
    items = _load_database(db_path=db_path)
    for item in items:
        if item.get("vec_id") == vec_id:
            return item
    return None


def get_next_vec_id(db_path: str = DATABASE_PATH) -> int:
    """
    获取指定数据库下一个可用的 vec_id。
    """
    items = _load_database(db_path=db_path)
    return len(items)