weather-alerts/app/config/loader.py

"""Typed configuration loader with YAML and environment variable support."""

import os
from dataclasses import dataclass, field
from pathlib import Path
from typing import Any, Optional

import yaml
from dotenv import load_dotenv

from app.models.alerts import AlertRules


@dataclass
class AppSettings:
    """Application-level settings."""

    name: str = "weather-alerts"
    version: str = "1.0.0"
    log_level: str = "INFO"


@dataclass
class WeatherSettings:
    """Weather API settings."""

    location: str = "viola,tn"
    hours_ahead: int = 24
    unit_group: str = "us"
    api_key: str = ""


@dataclass
class NtfySettings:
    """Ntfy notification settings."""

    server_url: str = "https://ntfy.sneakygeek.net"
    topic: str = "weather-alerts"
    priority: str = "high"
    tags: list[str] = field(default_factory=lambda: ["cloud", "warning"])
    access_token: str = ""


@dataclass
class NotificationSettings:
    """Notification settings container."""

    ntfy: NtfySettings = field(default_factory=NtfySettings)


@dataclass
class StateSettings:
    """State management settings."""

    file_path: str = "./data/state.json"
    dedup_window_hours: int = 24


@dataclass
class AlertSettings:
    """Alert configuration settings."""

    rules: AlertRules = field(default_factory=AlertRules)


@dataclass
class AISettings:
    """AI summarization settings."""

    enabled: bool = False
    model: str = "meta/meta-llama-3-8b-instruct"
    api_timeout: int = 60
    max_tokens: int = 500
    api_token: str = ""


@dataclass
class ChangeThresholds:
    """Thresholds for detecting significant changes between runs."""

    temperature: float = 5.0
    wind_speed: float = 10.0
    wind_gust: float = 10.0
    precipitation_prob: float = 20.0


@dataclass
class ChangeDetectionSettings:
    """Change detection settings."""

    enabled: bool = True
    thresholds: ChangeThresholds = field(default_factory=ChangeThresholds)


@dataclass
class AppConfig:
    """Complete application configuration."""

    app: AppSettings = field(default_factory=AppSettings)
    weather: WeatherSettings = field(default_factory=WeatherSettings)
    alerts: AlertSettings = field(default_factory=AlertSettings)
    notifications: NotificationSettings = field(default_factory=NotificationSettings)
    state: StateSettings = field(default_factory=StateSettings)
    ai: AISettings = field(default_factory=AISettings)
    change_detection: ChangeDetectionSettings = field(default_factory=ChangeDetectionSettings)


def load_config(
    config_path: Optional[str] = None,
    env_path: Optional[str] = None,
) -> AppConfig:
    """Load configuration from YAML file and environment variables.

    Args:
        config_path: Path to the YAML config file. Defaults to app/config/settings.yaml.
        env_path: Path to the .env file. Defaults to .env in the project root.

    Returns:
        A fully populated AppConfig instance.
    """
    # Load environment variables from .env file
    if env_path:
        load_dotenv(env_path)
    else:
        load_dotenv()

    # Determine config file path
    if config_path is None:
        config_path = os.environ.get(
            "WEATHER_ALERTS_CONFIG",
            str(Path(__file__).parent / "settings.yaml"),
        )

    # Load YAML config
    config_data: dict[str, Any] = {}
    config_file = Path(config_path)
    if config_file.exists():
        with open(config_file) as f:
            config_data = yaml.safe_load(f) or {}

    # Build configuration with defaults
    app_data = config_data.get("app", {})
    weather_data = config_data.get("weather", {})
    alerts_data = config_data.get("alerts", {})
    notifications_data = config_data.get("notifications", {})
    state_data = config_data.get("state", {})
    ai_data = config_data.get("ai", {})
    change_detection_data = config_data.get("change_detection", {})

    # Build app settings
    app_settings = AppSettings(
        name=app_data.get("name", "weather-alerts"),
        version=app_data.get("version", "1.0.0"),
        log_level=app_data.get("log_level", "INFO"),
    )

    # Build weather settings with API key from environment
    weather_settings = WeatherSettings(
        location=weather_data.get("location", "viola,tn"),
        hours_ahead=weather_data.get("hours_ahead", 24),
        unit_group=weather_data.get("unit_group", "us"),
        api_key=os.environ.get("VISUALCROSSING_API_KEY", ""),
    )

    # Build alert settings
    rules_data = alerts_data.get("rules", {})
    alert_settings = AlertSettings(rules=AlertRules.from_dict(rules_data))

    # Build notification settings with token from environment
    ntfy_data = notifications_data.get("ntfy", {})
    ntfy_settings = NtfySettings(
        server_url=ntfy_data.get("server_url", "https://ntfy.sneakygeek.net"),
        topic=ntfy_data.get("topic", "weather-alerts"),
        priority=ntfy_data.get("priority", "high"),
        tags=ntfy_data.get("tags", ["cloud", "warning"]),
        access_token=os.environ.get("NTFY_ACCESS_TOKEN", ""),
    )
    notification_settings = NotificationSettings(ntfy=ntfy_settings)

    # Build state settings
    state_settings = StateSettings(
        file_path=state_data.get("file_path", "./data/state.json"),
        dedup_window_hours=state_data.get("dedup_window_hours", 24),
    )

    # Build AI settings with token from environment
    ai_settings = AISettings(
        enabled=ai_data.get("enabled", False),
        model=ai_data.get("model", "meta/meta-llama-3-8b-instruct"),
        api_timeout=ai_data.get("api_timeout", 60),
        max_tokens=ai_data.get("max_tokens", 500),
        api_token=os.environ.get("REPLICATE_API_TOKEN", ""),
    )

    # Build change detection settings
    thresholds_data = change_detection_data.get("thresholds", {})
    change_thresholds = ChangeThresholds(
        temperature=thresholds_data.get("temperature", 5.0),
        wind_speed=thresholds_data.get("wind_speed", 10.0),
        wind_gust=thresholds_data.get("wind_gust", 10.0),
        precipitation_prob=thresholds_data.get("precipitation_prob", 20.0),
    )
    change_detection_settings = ChangeDetectionSettings(
        enabled=change_detection_data.get("enabled", True),
        thresholds=change_thresholds,
    )

    return AppConfig(
        app=app_settings,
        weather=weather_settings,
        alerts=alert_settings,
        notifications=notification_settings,
        state=state_settings,
        ai=ai_settings,
        change_detection=change_detection_settings,
    )