"""Typed configuration from the environment / `.env` — one settings class per subsystem (ARCHITECTURE §2.11)."""

from pathlib import Path
from typing import Annotated

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

_ENV = SettingsConfigDict(env_file=".env", env_file_encoding="utf-8", extra="ignore")


class TelegramSettings(BaseSettings):
    model_config = SettingsConfigDict(**_ENV, env_prefix="TELEGRAM_")

    bot_token: SecretStr


class AccessSettings(BaseSettings):
    model_config = _ENV

    # Bootstrap admins (SPEC A-8). Comma-separated in the env: ADMIN_IDS=1,2
    admin_ids: Annotated[frozenset[int], NoDecode] = frozenset()

    @field_validator("admin_ids", mode="before")
    @classmethod
    def _split_ids(cls, value: object) -> object:
        if isinstance(value, str):
            return frozenset(int(part) for part in value.replace(" ", "").split(",") if part)
        return value


class SourceCraftSettings(BaseSettings):
    model_config = SettingsConfigDict(**_ENV, env_prefix="SOURCECRAFT_")

    token: SecretStr = SecretStr("")
    api_url: str = "https://api.sourcecraft.tech"
    uploads_repo: str = "rogachevegorushka/tgit-uploads"
    # Web link to a CI run. The SPA answers 200 on any path, so the format is unverified — adjust if it 404s in UI.
    run_url_template: str = "https://sourcecraft.dev/{repo}/cicd/runs/{run}"
    timeout: float = Field(default=30.0, gt=0)
    max_attempts: int = Field(default=5, ge=1)


class RuntimeSettings(BaseSettings):
    model_config = _ENV

    log_level: str = "INFO"
    # Non-secret configs (texts, thresholds, prompts). Relative to the working dir: /srv/tgit in Docker.
    config_dir: Path = Path("config")
    # The heartbeat file is touched while the event loop is alive; the Docker healthcheck reads its age.
    heartbeat_file: Path = Path("/tmp/tgit-heartbeat")
    heartbeat_interval: float = Field(default=10.0, gt=0)
    heartbeat_max_age: float = Field(default=30.0, gt=0)


class Settings(BaseSettings):
    model_config = _ENV

    telegram: TelegramSettings = Field(default_factory=TelegramSettings)
    access: AccessSettings = Field(default_factory=AccessSettings)
    sourcecraft: SourceCraftSettings = Field(default_factory=SourceCraftSettings)
    runtime: RuntimeSettings = Field(default_factory=RuntimeSettings)