from functools import lru_cache
from typing import Literal
from zoneinfo import ZoneInfo, ZoneInfoNotFoundError

from pydantic import SecretStr, field_validator
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)

    host: str = '0.0.0.0'
    port: int = 8080
    codex_enabled: bool = True
    codex_command: str = 'codex'
    codex_timeout: float = 8
    devin_enabled: bool = True
    devin_api_key: SecretStr = SecretStr('')
    devin_api_url: str = 'https://api.devin.ai'
    devin_mode: Literal['enterprise', 'organization_sessions'] = 'enterprise'
    devin_org_id: str = ''
    devin_user_id: str = ''
    devin_session_window_days: int = 30
    devin_timeout: float = 8
    provider_cache_ttl: float = 8
    refresh_interval: int = 10
    timezone: str = 'Europe/Vienna'
    demo_mode: bool = False

    @field_validator('codex_timeout', 'devin_timeout', 'provider_cache_ttl')
    @classmethod
    def positive(cls, value: float) -> float:
        if value <= 0:
            raise ValueError('must be positive')
        return value

    @field_validator('refresh_interval')
    @classmethod
    def positive_interval(cls, value: int) -> int:
        if value < 1:
            raise ValueError('must be at least 1')
        return value

    @field_validator('devin_session_window_days')
    @classmethod
    def valid_session_window(cls, value: int) -> int:
        if not 1 <= value <= 365:
            raise ValueError('must be between 1 and 365')
        return value

    @field_validator('timezone')
    @classmethod
    def valid_timezone(cls, value: str) -> str:
        try:
            ZoneInfo(value)
        except ZoneInfoNotFoundError as exc:
            raise ValueError('invalid timezone') from exc
        return value


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