from functools import lru_cache

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


class Settings(BaseSettings):
    model_config = SettingsConfigDict(env_file=".env", env_file_encoding="utf-8", extra="ignore")

    openai_api_key: SecretStr
    chat_model: str = "gpt-4o-mini"
    chat_temperature: float | None = 0.0
    embedding_model: str = "text-embedding-3-small"
    embedding_dimensions: int = Field(default=1536, gt=0)

    neo4j_uri: str
    neo4j_username: str = "neo4j"
    neo4j_password: SecretStr
    neo4j_database: str = "neo4j"

    chunk_size: int = Field(default=900, gt=0)
    chunk_overlap: int = Field(default=150, ge=0)
    extraction_workers: int = Field(default=4, ge=1, le=16)

    vector_top_k: int = Field(default=5, ge=1, le=50)
    graph_max_hops: int = Field(default=2, ge=1, le=4)
    graph_max_facts: int = Field(default=40, ge=1, le=200)


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