/**
 * Weather API service using Open-Meteo (free, no API key required)
 * https://open-meteo.com/
 */

export interface WeatherData {
  temperature: number; // Celsius
  temperatureFahrenheit: number; // Fahrenheit
  feelsLike: number; // Celsius
  feelsLikeFahrenheit: number; // Fahrenheit
  weatherCode: number; // WMO Weather Code
  weatherDescription: string;
  weatherIcon: string; // Emoji
  precipitation: number; // mm
  precipitationProbability: number; // %
  humidity: number; // %
  windSpeed: number; // km/h
  windDirection: number; // degrees
  windDirectionLabel: string; // N, NE, E, etc.
  cloudCover: number; // %
  visibility: number; // meters
  uvIndex: number;
  isDay: boolean;
  timestamp: number;
}

export interface AirQualityData {
  aqi: number; // Air Quality Index (US EPA standard)
  aqiLabel: string; // Good, Moderate, Unhealthy, etc.
  aqiColor: string; // Color for UI
  pm25: number; // PM2.5 concentration
  pm10: number; // PM10 concentration
  timestamp: number;
}

export interface WeatherForecast {
  daily: {
    date: string;
    maxTemp: number;
    minTemp: number;
    weatherCode: number;
    weatherIcon: string;
    precipitationProbability: number;
  }[];
}

export interface SkateabilityScore {
  score: number; // 0-100
  label: string; // Perfect, Good, Okay, Poor, Unrideable
  color: string; // green, yellow, orange, red
  reasons: string[];
}

// WMO Weather Codes to emoji and description
const weatherCodes: Record<number, { icon: string; description: string }> = {
  0: { icon: '☀️', description: 'Clear sky' },
  1: { icon: '🌤️', description: 'Mainly clear' },
  2: { icon: '⛅', description: 'Partly cloudy' },
  3: { icon: '☁️', description: 'Overcast' },
  45: { icon: '🌫️', description: 'Foggy' },
  48: { icon: '🌫️', description: 'Depositing rime fog' },
  51: { icon: '🌦️', description: 'Light drizzle' },
  53: { icon: '🌦️', description: 'Moderate drizzle' },
  55: { icon: '🌧️', description: 'Dense drizzle' },
  56: { icon: '🌧️', description: 'Light freezing drizzle' },
  57: { icon: '🌧️', description: 'Dense freezing drizzle' },
  61: { icon: '🌧️', description: 'Slight rain' },
  63: { icon: '🌧️', description: 'Moderate rain' },
  65: { icon: '🌧️', description: 'Heavy rain' },
  66: { icon: '🌧️', description: 'Light freezing rain' },
  67: { icon: '🌧️', description: 'Heavy freezing rain' },
  71: { icon: '🌨️', description: 'Slight snow' },
  73: { icon: '🌨️', description: 'Moderate snow' },
  75: { icon: '🌨️', description: 'Heavy snow' },
  77: { icon: '🌨️', description: 'Snow grains' },
  80: { icon: '🌦️', description: 'Slight rain showers' },
  81: { icon: '🌧️', description: 'Moderate rain showers' },
  82: { icon: '⛈️', description: 'Violent rain showers' },
  85: { icon: '🌨️', description: 'Slight snow showers' },
  86: { icon: '🌨️', description: 'Heavy snow showers' },
  95: { icon: '⛈️', description: 'Thunderstorm' },
  96: { icon: '⛈️', description: 'Thunderstorm with slight hail' },
  99: { icon: '⛈️', description: 'Thunderstorm with heavy hail' },
};

function getWeatherInfo(code: number): { icon: string; description: string } {
  return weatherCodes[code] || { icon: '❓', description: 'Unknown' };
}

function getWindDirection(degrees: number): string {
  const directions = ['N', 'NNE', 'NE', 'ENE', 'E', 'ESE', 'SE', 'SSE', 'S', 'SSW', 'SW', 'WSW', 'W', 'WNW', 'NW', 'NNW'];
  const index = Math.round(degrees / 22.5) % 16;
  return directions[index];
}

function celsiusToFahrenheit(celsius: number): number {
  return Math.round((celsius * 9 / 5) + 32);
}

function getAQIInfo(aqi: number): { label: string; color: string } {
  if (aqi <= 50) return { label: 'Good', color: '#00e400' };
  if (aqi <= 100) return { label: 'Moderate', color: '#ffff00' };
  if (aqi <= 150) return { label: 'Unhealthy for Sensitive Groups', color: '#ff7e00' };
  if (aqi <= 200) return { label: 'Unhealthy', color: '#ff0000' };
  if (aqi <= 300) return { label: 'Very Unhealthy', color: '#8f3f97' };
  return { label: 'Hazardous', color: '#7e0023' };
}

/**
 * Fetch current weather for a location
 */
export async function fetchWeather(lat: number, lng: number): Promise<WeatherData> {
  const params = new URLSearchParams({
    latitude: lat.toFixed(6),
    longitude: lng.toFixed(6),
    current: 'temperature_2m,relative_humidity_2m,apparent_temperature,is_day,precipitation,weather_code,cloud_cover,wind_speed_10m,wind_direction_10m,uv_index',
    temperature_unit: 'celsius',
    wind_speed_unit: 'kmh',
    precipitation_unit: 'mm',
    timezone: 'auto',
  });

  const response = await fetch(`https://api.open-meteo.com/v1/forecast?${params}`);
  if (!response.ok) throw new Error('Failed to fetch weather data');

  const data = await response.json();
  const current = data.current;

  const weatherInfo = getWeatherInfo(current.weather_code);

  return {
    temperature: Math.round(current.temperature_2m),
    temperatureFahrenheit: celsiusToFahrenheit(current.temperature_2m),
    feelsLike: Math.round(current.apparent_temperature),
    feelsLikeFahrenheit: celsiusToFahrenheit(current.apparent_temperature),
    weatherCode: current.weather_code,
    weatherDescription: weatherInfo.description,
    weatherIcon: weatherInfo.icon,
    precipitation: current.precipitation || 0,
    precipitationProbability: 0, // Not available in current weather
    humidity: current.relative_humidity_2m,
    windSpeed: Math.round(current.wind_speed_10m),
    windDirection: current.wind_direction_10m,
    windDirectionLabel: getWindDirection(current.wind_direction_10m),
    cloudCover: current.cloud_cover,
    visibility: 10000, // Open-Meteo doesn't provide visibility in free tier
    uvIndex: current.uv_index || 0,
    isDay: current.is_day === 1,
    timestamp: Date.now(),
  };
}

/**
 * Fetch air quality data for a location
 */
export async function fetchAirQuality(lat: number, lng: number): Promise<AirQualityData> {
  const params = new URLSearchParams({
    latitude: lat.toFixed(6),
    longitude: lng.toFixed(6),
    current: 'us_aqi,pm10,pm2_5',
    timezone: 'auto',
  });

  const response = await fetch(`https://air-quality-api.open-meteo.com/v1/air-quality?${params}`);
  if (!response.ok) throw new Error('Failed to fetch air quality data');

  const data = await response.json();
  const current = data.current;

  const aqi = current.us_aqi || 0;
  const aqiInfo = getAQIInfo(aqi);

  return {
    aqi,
    aqiLabel: aqiInfo.label,
    aqiColor: aqiInfo.color,
    pm25: current.pm2_5 || 0,
    pm10: current.pm10 || 0,
    timestamp: Date.now(),
  };
}

/**
 * Fetch 3-day weather forecast for a location
 */
export async function fetchWeatherForecast(lat: number, lng: number): Promise<WeatherForecast> {
  const params = new URLSearchParams({
    latitude: lat.toFixed(6),
    longitude: lng.toFixed(6),
    daily: 'weather_code,temperature_2m_max,temperature_2m_min,precipitation_probability_max',
    temperature_unit: 'celsius',
    timezone: 'auto',
    forecast_days: '3',
  });

  const response = await fetch(`https://api.open-meteo.com/v1/forecast?${params}`);
  if (!response.ok) throw new Error('Failed to fetch forecast data');

  const data = await response.json();

  return {
    daily: data.daily.time.map((date: string, index: number) => {
      const weatherInfo = getWeatherInfo(data.daily.weather_code[index]);
      return {
        date,
        maxTemp: Math.round(data.daily.temperature_2m_max[index]),
        minTemp: Math.round(data.daily.temperature_2m_min[index]),
        weatherCode: data.daily.weather_code[index],
        weatherIcon: weatherInfo.icon,
        precipitationProbability: data.daily.precipitation_probability_max[index] || 0,
      };
    }),
  };
}

/**
 * Calculate skateability score based on weather conditions
 */
export function calculateSkateability(
  weather: WeatherData,
  airQuality?: AirQualityData
): SkateabilityScore {
  let score = 100;
  const reasons: string[] = [];

  // Precipitation (dealbreaker)
  if (weather.precipitation > 0) {
    score = 0;
    reasons.push('Currently raining');
    return {
      score,
      label: 'Unrideable',
      color: '#ff0000',
      reasons,
    };
  }

  // Check for rain/snow conditions
  const isRaining = [51, 53, 55, 56, 57, 61, 63, 65, 66, 67, 80, 81, 82].includes(weather.weatherCode);
  const isSnowing = [71, 73, 75, 77, 85, 86].includes(weather.weatherCode);
  const isThunderstorm = [95, 96, 99].includes(weather.weatherCode);

  if (isRaining || isSnowing || isThunderstorm) {
    score = 0;
    reasons.push(isSnowing ? 'Snowing' : isThunderstorm ? 'Thunderstorm' : 'Raining');
    return {
      score,
      label: 'Unrideable',
      color: '#ff0000',
      reasons,
    };
  }

  // Temperature
  if (weather.temperature < 0) {
    score -= 50;
    reasons.push('Freezing temperature');
  } else if (weather.temperature < 5) {
    score -= 30;
    reasons.push('Very cold');
  } else if (weather.temperature > 38) {
    score -= 40;
    reasons.push('Extremely hot');
  } else if (weather.temperature > 32) {
    score -= 20;
    reasons.push('Very hot');
  }

  // Wind
  if (weather.windSpeed > 40) {
    score -= 40;
    reasons.push('Very strong wind');
  } else if (weather.windSpeed > 25) {
    score -= 25;
    reasons.push('Strong wind');
  } else if (weather.windSpeed > 15) {
    score -= 10;
    reasons.push('Moderate wind');
  }

  // Air quality
  if (airQuality) {
    if (airQuality.aqi > 200) {
      score -= 40;
      reasons.push('Very unhealthy air');
    } else if (airQuality.aqi > 150) {
      score -= 25;
      reasons.push('Unhealthy air');
    } else if (airQuality.aqi > 100) {
      score -= 10;
      reasons.push('Moderate air quality');
    }
  }

  // Humidity (affects grip)
  if (weather.humidity > 90) {
    score -= 15;
    reasons.push('Very humid');
  } else if (weather.humidity > 75) {
    score -= 5;
    reasons.push('Humid');
  }

  // UV Index (safety concern)
  if (weather.uvIndex > 10) {
    score -= 10;
    reasons.push('Extreme UV - wear sunscreen');
  } else if (weather.uvIndex > 7) {
    score -= 5;
    reasons.push('High UV - sun protection recommended');
  }

  // Ensure score doesn't go below 0
  score = Math.max(0, score);

  // If no negative reasons, add positive feedback
  if (reasons.length === 0) {
    reasons.push('Perfect skating conditions');
  }

  let label: string;
  let color: string;

  if (score >= 85) {
    label = 'Perfect';
    color = '#00e400';
  } else if (score >= 70) {
    label = 'Good';
    color = '#92d050';
  } else if (score >= 50) {
    label = 'Okay';
    color = '#ffff00';
  } else if (score >= 25) {
    label = 'Poor';
    color = '#ff7e00';
  } else {
    label = 'Bad';
    color = '#ff0000';
  }

  return {
    score,
    label,
    color,
    reasons,
  };
}