from typing import Literal

from pydantic import Field
from pydantic_settings import BaseSettings, SettingsConfigDict

_ENV_FILE = ".env"


class DatabaseConfig(BaseSettings):
    model_config = SettingsConfigDict(env_prefix="DB_", env_file=_ENV_FILE, extra="ignore")

    host: str = "127.0.0.1"
    port: int = 3306
    user: str = "root"
    password: str = ""
    database: str = ""
    pool_min: int = 1
    pool_max: int = 10
    connect_timeout: int = 30


class QueryConfig(BaseSettings):
    model_config = SettingsConfigDict(env_prefix="QUERY_", env_file=_ENV_FILE, extra="ignore")

    max_rows: int = 1000
    timeout_seconds: int = 30
    allow_write: bool = False


class ServerConfig(BaseSettings):
    model_config = SettingsConfigDict(env_prefix="MCP_", env_file=_ENV_FILE, extra="ignore")

    transport: Literal["stdio", "http"] = "stdio"
    host: str = "127.0.0.1"
    port: int = 8000
    # LOG_LEVEL has no MCP_ prefix so it's declared with an explicit alias
    log_level: str = Field(default="INFO", validation_alias="LOG_LEVEL")


class Config(BaseSettings):
    model_config = SettingsConfigDict(env_file=_ENV_FILE, extra="ignore")

    database: DatabaseConfig = Field(default_factory=DatabaseConfig)
    query: QueryConfig = Field(default_factory=QueryConfig)
    server: ServerConfig = Field(default_factory=ServerConfig)