import json
from functools import lru_cache
from typing import Annotated, Literal

from pydantic import Field, field_validator
from pydantic_settings import BaseSettings, NoDecode, SettingsConfigDict


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

    hermes_bin: str = Field(default="hermes", alias="HERMES_BIN")
    hermes_home: str | None = Field(default=None, alias="HERMES_HOME")
    default_board: str = Field(default="default", alias="HERMES_KANBAN_BOARD")
    auth_mode: Literal["telegram", "none", "dev"] = Field(default="dev", alias="KANBAN_UI_AUTH_MODE")
    telegram_bot_token: str | None = Field(default=None, alias="TELEGRAM_BOT_TOKEN")
    telegram_allowed_user_ids: Annotated[list[int], NoDecode] = Field(default_factory=list, alias="TELEGRAM_ALLOWED_USER_IDS")
    allowed_origins: Annotated[list[str], NoDecode] = Field(default_factory=lambda: ["http://localhost:5173"], alias="KANBAN_UI_ALLOWED_ORIGINS")
    command_timeout_seconds: int = Field(default=30, alias="KANBAN_UI_COMMAND_TIMEOUT_SECONDS")
    frontend_dist_dir: str | None = Field(default=None, alias="KANBAN_UI_FRONTEND_DIST_DIR")

    @field_validator("telegram_allowed_user_ids", mode="before")
    @classmethod
    def parse_user_ids(cls, value):
        if value is None or value == "":
            return []
        if isinstance(value, str):
            value = value.strip()
            if value.startswith("["):
                try:
                    value = json.loads(value)
                except json.JSONDecodeError:
                    pass
        if isinstance(value, str):
            return [int(part.strip()) for part in value.split(",") if part.strip()]
        if isinstance(value, (list, tuple)):
            return [int(v) for v in value]
        return value

    @field_validator("allowed_origins", mode="before")
    @classmethod
    def parse_origins(cls, value):
        if value is None or value == "":
            return []
        if isinstance(value, str):
            value = value.strip()
            if value.startswith("["):
                try:
                    value = json.loads(value)
                except json.JSONDecodeError:
                    pass
        if isinstance(value, str):
            return [part.strip() for part in value.split(",") if part.strip()]
        if isinstance(value, (list, tuple)):
            return [str(v) for v in value]
        return value


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