from loguru import logger
from pydantic import EmailStr, 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.
    """

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

    # 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"

    # HTTP Server Configuration
    http_host: str = "0.0.0.0"
    http_port: PositiveInt = 8080

    # 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
    vectorized_chunks_collection_name: str = "vectorized_chunks"
    vectorized_chunks_search_index_name: Optional[str] = None
    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: EmailStr
    google_token_uri: str = "https://oauth2.googleapis.com/token"

    # File Monitoring Configuration
    file_monitor_root_path: str = ""

    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__))

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