"""Environment settings and the model registry loaded from a JSON file."""
import json
from pathlib import Path

from pydantic import BaseModel, ValidationError
from pydantic_settings import BaseSettings, SettingsConfigDict

from .errors import ConfigError

REPO_ROOT = Path(__file__).resolve().parent.parent


class ModelEntry(BaseModel):
    """A registry record: an API model id maps to one workflow file."""

    workflow: Path
    owned_by: str = "comfy-adapter"


class Settings(BaseSettings):
    model_config = SettingsConfigDict(env_file=".env", extra="ignore")

    comfy_base_url: str = "http://192.168.0.3:8188"
    adapter_api_key: str = ""
    execution_timeout: float = 300.0
    poll_interval: float = 1.5
    # JSON file mapping an API model id to its workflow. Required; no defaults in code.
    models_file: Path = REPO_ROOT / "models.json"
    # Validate collected graphs on the ComfyUI server (POST /prompt?front=false) at startup.
    validate_templates_on_server: bool = True

    def load_registry(self) -> dict[str, ModelEntry]:
        """Load the model registry, preserving declaration order (first = preferred).

        Fail-fast: a missing or malformed file raises ConfigError and blocks startup.
        """
        try:
            raw = json.loads(self.models_file.read_text(encoding="utf-8"))
        except FileNotFoundError as e:
            raise ConfigError(f"model registry file not found: {self.models_file}") from e
        except json.JSONDecodeError as e:
            raise ConfigError(f"model registry is not valid JSON ({self.models_file}): {e}") from e
        if not isinstance(raw, dict) or not raw:
            raise ConfigError(f"model registry must be a non-empty object of model entries: {self.models_file}")
        registry: dict[str, ModelEntry] = {}
        for model_id, spec in raw.items():
            try:
                registry[model_id] = ModelEntry.model_validate(spec)
            except ValidationError as e:
                raise ConfigError(f"model '{model_id}' has an invalid entry: {e}") from e
        return registry


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