from __future__ import annotations

from functools import lru_cache
from pathlib import Path

from pydantic import field_validator
from pydantic_settings import BaseSettings, SettingsConfigDict

REPO_ROOT = Path(__file__).resolve().parents[2]
DATA_DIR = REPO_ROOT / "data"


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

    app_name: str = "Crypto Trader"
    env: str = "dev"
    host: str = "0.0.0.0"
    port: int = 8000

    database_url: str = "sqlite:///./data/trader.db"

    mode: str = "paper"
    exchange: str = "binance"
    symbol: str = "BTC/USDT"
    timeframe: str = "1m"
    poll_interval: float = 5.0
    candle_limit: int = 200

    starting_balance: float = 10_000.0
    fee_bps: float = 10.0
    slippage_bps: float = 5.0

    exchange_api_key: str = ""
    exchange_api_secret: str = ""
    exchange_sandbox: bool = False

    cors_origins: str = "*"

    @field_validator("mode")
    @classmethod
    def _validate_mode(cls, value: str) -> str:
        value = value.lower().strip()
        if value not in {"paper", "live"}:
            raise ValueError("mode must be 'paper' or 'live'")
        return value

    @property
    def cors_origin_list(self) -> list[str]:
        return [origin.strip() for origin in self.cors_origins.split(",") if origin.strip()]

    @property
    def is_live(self) -> bool:
        return self.mode == "live"


@lru_cache
def get_settings() -> Settings:
    settings = Settings()
    DATA_DIR.mkdir(parents=True, exist_ok=True)
    return settings