from __future__ import annotations

from functools import lru_cache

from pydantic import Field, field_validator
from pydantic_settings import BaseSettings, SettingsConfigDict

class Settings(BaseSettings):
    model_config = SettingsConfigDict(
        extra="ignore",
    )

    app_name: str = "Brand Chatbot API"
    api_prefix: str = "/api"
    cors_origins: list[str] = Field(default_factory=list)
    blog_posts_csv_path: str = "data/blog/blog_posts_rows.csv"
    blog_chunks_csv_path: str = "data/blog/blog_chunks_rows.csv"
    blog_vector_cache_path: str = "data/blog/blog_vector_cache.json"
    agent_sessions_db_path: str = "agent_conversations.db"

    database_url: str = "sqlite:///./brand_chatbot.db"

    openai_api_key: str | None = None
    openai_base_url: str | None = None
    openai_chat_model: str = "gpt-5.4-mini"
    openai_guardrail_model: str = "gpt-4o-mini"
    openai_embedding_model: str = "text-embedding-3-small"
    agents_disable_tracing: bool = True

    request_timeout_seconds: int = 45
    retrieval_top_k: int = 4
    retrieval_faiss_candidate_limit: int = 24
    retrieval_vector_threshold: float = 0.14
    conversation_history_window: int = 6
    embedding_batch_size: int = 32
    lead_notification_provider: str = "gmail_smtp"
    lead_notification_to_email: str | None = None
    lead_notification_from_email: str | None = None
    lead_notification_from_name: str = "Brand Chatbot"
    gmail_smtp_host: str = "smtp.gmail.com"
    gmail_smtp_port: int = 587
    gmail_smtp_username: str | None = None
    gmail_smtp_password: str | None = None
    gmail_smtp_starttls: bool = True
    ceo_contact_email: str = "antti@blinkhelsinki.fi"

    @field_validator("cors_origins", mode="before")
    @classmethod
    def split_origins(cls, value: str | list[str]) -> list[str]:
        if isinstance(value, str):
            return [item.strip() for item in value.split(",") if item.strip()]
        return value

    @property
    def openai_key(self) -> str:
        api_key = self.openai_api_key
        if not api_key:
            raise RuntimeError("Missing OpenAI API key. Set OPENAI_API_KEY in .env.")
        return api_key

    @property
    def normalized_openai_base_url(self) -> str | None:
        api_base = self.openai_base_url
        if not api_base:
            return None
        return api_base.strip() or None




@lru_cache
def get_settings() -> Settings:
    return Settings()