import asyncio
from typing import List, Dict, Any

from app.models.instance import Instance
from app.schemas.instance import ConnectionTestResult


class InstanceService:
    @staticmethod
    async def test_connection(instance: Instance) -> ConnectionTestResult:
        try:
            if instance.db_type == "mysql":
                import aiomysql
                conn = await asyncio.wait_for(
                    aiomysql.connect(
                        host=instance.host,
                        port=instance.port,
                        user=instance.username,
                        password=instance.password,
                        database=instance.database or None,
                    ),
                    timeout=10,
                )
                async with conn.cursor() as cur:
                    await cur.execute("SELECT VERSION()")
                    version = (await cur.fetchone())[0]
                conn.close()
                return ConnectionTestResult(success=True, message="连接成功", version=str(version))

            return ConnectionTestResult(success=False, message=f"暂不支持 {instance.db_type} 连接测试")
        except asyncio.TimeoutError:
            return ConnectionTestResult(success=False, message="连接超时")
        except Exception as e:
            return ConnectionTestResult(success=False, message=f"连接失败: {str(e)}")

    @staticmethod
    async def list_databases(instance: Instance) -> List[str]:
        if instance.db_type != "mysql":
            return []

        import aiomysql
        conn = await aiomysql.connect(
            host=instance.host, port=instance.port,
            user=instance.username, password=instance.password,
        )
        async with conn.cursor() as cur:
            await cur.execute("SHOW DATABASES")
            rows = await cur.fetchall()
        conn.close()
        return [row[0] for row in rows if row[0] not in ("information_schema", "mysql", "performance_schema", "sys")]

    @staticmethod
    async def list_tables(instance: Instance, database: str) -> List[Dict[str, Any]]:
        if instance.db_type != "mysql":
            return []

        import aiomysql
        conn = await aiomysql.connect(
            host=instance.host, port=instance.port,
            user=instance.username, password=instance.password,
            database=database,
        )
        async with conn.cursor() as cur:
            await cur.execute("SHOW TABLES")
            tables = [row[0] for row in await cur.fetchall()]

            result = []
            for table in tables:
                await cur.execute(f"SHOW TABLE STATUS LIKE '{table}'")
                status = await cur.fetchone()
                result.append({
                    "name": table,
                    "engine": status[1],
                    "rows": status[4],
                    "size": status[6],
                    "comment": status[17],
                })
        conn.close()
        return result