"""Configuration management using pydantic-settings."""

from typing import Literal

from pydantic import Field
from pydantic_settings import BaseSettings, SettingsConfigDict


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

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

    # Discord Configuration
    discord_token: str = Field(..., description="Discord bot token")

    # AI Provider Configuration
    ai_provider: Literal["openai", "openrouter", "anthropic", "gemini"] = Field(
        "openai", description="Which AI provider to use"
    )
    ai_model: str = Field("gpt-4o", description="AI model to use")
    ai_max_tokens: int = Field(1024, ge=100, le=4096, description="Max tokens for AI response")
    ai_temperature: float = Field(0.7, ge=0.0, le=2.0, description="AI temperature")

    # Provider API Keys
    openai_api_key: str | None = Field(None, description="OpenAI API key")
    openrouter_api_key: str | None = Field(None, description="OpenRouter API key")
    anthropic_api_key: str | None = Field(None, description="Anthropic API key")
    gemini_api_key: str | None = Field(None, description="Google Gemini API key")

    # Logging
    log_level: str = Field("INFO", description="Logging level")

    # Bot Identity
    bot_name: str = Field("AI Bot", description="Bot display name")
    bot_personality: str = Field(
        "helpful and friendly",
        description="Bot personality description for system prompt",
    )
    bot_description: str = Field(
        "I'm an AI assistant here to help you.",
        description="Bot description shown when mentioned without a message",
    )
    bot_status: str = Field(
        "for mentions",
        description="Bot status message (shown as 'Watching ...')",
    )

    # System Prompt (optional override)
    system_prompt: str | None = Field(
        None,
        description="Custom system prompt. If not set, a default is generated from bot_name and bot_personality",
    )

    # Conversation Settings
    max_conversation_history: int = Field(
        20, description="Max messages to keep in conversation memory per user"
    )

    def get_api_key(self) -> str:
        """Get the API key for the configured provider."""
        key_map = {
            "openai": self.openai_api_key,
            "openrouter": self.openrouter_api_key,
            "anthropic": self.anthropic_api_key,
            "gemini": self.gemini_api_key,
        }
        key = key_map.get(self.ai_provider)
        if not key:
            raise ValueError(
                f"No API key configured for provider '{self.ai_provider}'. "
                f"Set {self.ai_provider.upper()}_API_KEY in your environment."
            )
        return key


# Global settings instance
settings = Settings()