import asyncio
from pathlib import Path
from typing import Optional

import yaml
from pydantic import BaseModel, Field
from pydantic_settings import BaseSettings


class FHobSettings(BaseModel):
    symbols: list[str] = Field(
        default_factory=list,
        description="Trading pairs to subscribe to. Empty = no subscriptions. oe_em adds pairs via REST.",
    )
    log_level: str = Field(default="INFO", description="Logging level")
    log_file: Path = Field(
        default=Path("/tmp/fh_ob.log"),
        description="Path to log file. Logs are written here in addition to stdout.",
    )
    socket_path: Path = Field(
        default=Path("/tmp/fh_ob.sock"),
        description="Unix domain socket path for OE+EM",
    )
    rest_host: str = Field(default="0.0.0.0", description="FastAPI debug host")
    rest_port: int = Field(default=8000, description="FastAPI debug port")
    ws_url: str = Field(
        default="wss://ws-api-spot.kucoin.com",
        description="KuCoin WebSocket endpoint",
    )
    token_url: str = Field(
        default="https://api.kucoin.com/api/v1/bullet-public",
        description="KuCoin public token endpoint",
    )
    reconnect_base_delay: float = Field(
        default=1.0,
        description="Base delay for reconnect exponential backoff (seconds)",
    )
    reconnect_max_delay: float = Field(
        default=60.0,
        description="Max delay for reconnect exponential backoff (seconds)",
    )
    heartbeat_interval: float = Field(
        default=18.0,
        description="WS ping interval (seconds) - KuCoin uses 18s",
    )


class Settings(BaseSettings):
    fh_ob: FHobSettings = Field(default_factory=FHobSettings)

    @classmethod
    async def from_yaml(cls, path: Path) -> "Settings":
        loop = asyncio.get_running_loop()

        def _read() -> dict:
            with open(path) as f:
                return yaml.safe_load(f) or {}

        data = await loop.run_in_executor(None, _read)
        fh_ob_data = data.get("fh_ob", {})
        if fh_ob_data.get("symbols") is None:
            fh_ob_data["symbols"] = []
        return cls(**data)

    model_config = {"env_prefix": "TRIARB_", "extra": "ignore"}