from loguru import logger
from pydantic import Field, MongoDsn, NonNegativeFloat, NonNegativeInt, PositiveInt, SecretStr
from pydantic_settings import BaseSettings, SettingsConfigDict
from types import MappingProxyType
from typing import Literal, Mapping, Optional, Self

class Settings(BaseSettings):
    """
    Application settings loaded from environment variables.
    """

    def __init__(self: Self, **data) -> None:
        super().__init__(**data)
        logger.debug("Created {}", self.__class__.__name__)
        if self.__pydantic_extra__:
            logger.warning("Extra unrecognized environment variables were provided: {}", ", ".join(self.__pydantic_extra__))

    # Logging Configuration ― not actually used to configure Loguru, but defined to prevent warnings about “unknown” environment variables
    LOG_LEVEL: Literal["DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL"] = Field(default_factory=lambda data: "DEBUG" if data.get("DEBUG", False) else "INFO")
    LOG_FORMAT: Literal["text", "json"] = "json"

    # APScheduler Configuration
    SCHEDULER_TIMEZONE: Optional[str] = "UTC"

    # Slack Configuration
    SLACK_BOT_TOKEN: SecretStr
    SLACK_APP_TOKEN: SecretStr

    # Vectorization Configuration
    EMBEDDING_MODEL: str
    VECTOR_DIMENSION: PositiveInt
    CHUNK_SIZE: PositiveInt
    CHUNK_OVERLAP: NonNegativeInt
    TOP_K_MATCHES: PositiveInt

    # MongoDB Configuration
    MONGODB_URI: SecretStr # TODO: Contemplate switching to MongoDsn type for the main URL, and separate out the credentials to SecretStr variables.
    MONGODB_NAME: str
    SCORE_THRESHOLD: NonNegativeFloat

    # Hugging Face Configuration
    HF_API_TOKEN: Optional[SecretStr] = None # TODO: Currently, this is unused.

    # OpenAI Configuration
    OPENAI_API_KEY: SecretStr
    CHAT_MODEL: str
    MAX_TOKENS: PositiveInt 
    TEMPERATURE: NonNegativeFloat
    SYSTEM_PROMPT: str

    # Google Drive Configuration
    GOOGLE_DRIVE_ROOT_ID: str
    GOOGLE_PROJECT_ID: str
    GOOGLE_PRIVATE_KEY_ID: SecretStr
    GOOGLE_PRIVATE_KEY: SecretStr
    GOOGLE_CLIENT_ID: str
    GOOGLE_CLIENT_EMAIL: str
    GOOGLE_AUTH_URI: str = "https://accounts.google.com/o/oauth2/auth"
    GOOGLE_TOKEN_URI: str = "https://oauth2.googleapis.com/token"
    GOOGLE_AUTH_PROVIDER_CERT_URL: str = "https://www.googleapis.com/oauth2/v1/certs"
    GOOGLE_CLIENT_CERT_URL: str = "https://www.googleapis.com/robot/v1/metadata/x509/ctp-slack-bot-714%40voltaic-reducer-294821.iam.gserviceaccount.com"
    GOOGLE_UNIVERSE_DOMAIN: str = "googleapis.com"

    # File Monitoring Configuration
    FILE_MONITOR_ROOT_PATH: str = ""

    model_config = SettingsConfigDict(
        env_file=".env",
        env_file_encoding="utf-8",
        case_sensitive=True,
        extra="allow",
        frozen=True
    )

    def get_extra_environment_variables(self: Self) -> Mapping[str, str]:
        return MappingProxyType(self.__pydantic_extra__)