"""SQLite / MySQL 连接与幂等初始化模板。

模板默认只建数据管理元数据表。业务表由复制后的技能自行 CREATE，并同步展示元数据。
配置了 MYSQL_DSN 时走 MySQL 云库，否则使用本地 {skill_slug}.db。见 references/DATA_SOURCES.md。
"""

from __future__ import annotations

import sqlite3

from db.backend import get_mysql_dsn, parse_mysql_dsn, resolve_backend
from db.cursor_compat import AdaptedConnection
from db.display_metadata import init_display_metadata
from util.runtime_paths import get_db_path


def get_conn() -> AdaptedConnection:
    backend = resolve_backend()
    if backend == "mysql":
        import pymysql

        params = parse_mysql_dsn(get_mysql_dsn())
        raw = pymysql.connect(
            host=str(params["host"]),
            port=int(params["port"]),
            user=str(params["user"]),
            password=str(params["password"]),
            database=str(params["database"]),
            charset="utf8mb4",
            autocommit=False,
        )
        return AdaptedConnection(raw, "mysql")

    raw = sqlite3.connect(get_db_path())
    return AdaptedConnection(raw, "sqlite")


def init_db() -> None:
    conn = get_conn()
    try:
        cur = conn.cursor()
        init_display_metadata(cur)
        conn.commit()
    finally:
        conn.close()


def describe_active_store() -> dict[str, str]:
    backend = resolve_backend()
    if backend == "mysql":
        params = parse_mysql_dsn(get_mysql_dsn())
        return {
            "backend": "mysql",
            "host": str(params["host"]),
            "database": str(params["database"]),
        }
    return {
        "backend": "sqlite",
        "db_path": get_db_path(),
    }