"""应用配置：读取 settings.json，支持多数据源切换（不硬编码连接信息）。"""
import json
import os
from functools import lru_cache

BASE_DIR = os.path.dirname(os.path.abspath(__file__))
DEFAULT_SETTINGS_PATH = os.path.join(os.path.dirname(BASE_DIR), "settings.json")


@lru_cache(maxsize=1)
def load_settings() -> dict:
    path = os.environ.get("EASYSCREEN_SETTINGS", DEFAULT_SETTINGS_PATH)
    with open(path, "r", encoding="utf-8") as f:
        return json.load(f)


def get_active_db() -> dict:
    settings = load_settings()
    name = settings["active_db"]
    return settings["databases"][name]


def get_database_url() -> str:
    db = get_active_db()
    if db["type"] == "sqlite":
        return f"sqlite:///{os.path.join(os.path.dirname(BASE_DIR), db['path'])}"
    if db["type"] == "mysql":
        password = db.get("password", "")
        auth = db["user"] if not password else f"{db['user']}:{password}"
        return (
            f"mysql+pymysql://{auth}@{db['host']}:{db['port']}/"
            f"{db['database_name']}?charset={db.get('charset', 'utf8mb4')}"
        )
    raise ValueError(f"不支持的数据库类型: {db['type']}")


def get_server_config() -> dict:
    return load_settings()["server"]


def get_admin_config() -> dict:
    return load_settings()["admin"]