"""Pydantic settings loader for Multi_Swarm_Coevolutive.

Loads configuration from environment variables and an optional ``.env`` file
in the project root. Required secrets are validated at instantiation time.
"""

from pathlib import Path

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",
        case_sensitive=False,
    )

    cerbero_base_url: str = "http://localhost:9000"
    cerbero_testnet_token: SecretStr
    cerbero_mainnet_token: SecretStr | None = None
    cerbero_bot_tag: str = "swarm-poc-phase1"

    openrouter_api_key: SecretStr

    llm_model_tier_s: str = "google/gemini-3-flash-preview"
    llm_model_tier_a: str = "deepseek/deepseek-v4-flash"
    llm_model_tier_b: str = "deepseek/deepseek-v4-flash"
    llm_model_tier_c: str = "qwen/qwen-2.5-72b-instruct"
    llm_model_tier_d: str = "openai/gpt-oss-20b"
    openrouter_base_url: str = "https://openrouter.ai/api/v1"

    run_name: str = "phase1-spike-001"
    data_dir: Path = Field(default=Path("./data"))
    series_dir: Path = Field(default=Path("./series"))
    db_path: Path = Field(default=Path("./runs.db"))


def load_settings() -> Settings:
    # Required fields are populated from environment / .env, not init kwargs.
    return Settings()  # type: ignore[call-arg]