import {
  CurrentWeatherResponse,
  ForecastResponse,
  HistoricalResponse,
  AssessmentResponse,
  Thresholds,
  APIError,
} from './types'

const API_BASE_URL = process.env.NEXT_PUBLIC_API_URL || 'http://localhost:8080/api/v1'

class APIClient {
  private baseURL: string

  constructor(baseURL: string) {
    this.baseURL = baseURL
  }

  private async request<T>(
    endpoint: string,
    options?: RequestInit
  ): Promise<T> {
    const url = `${this.baseURL}${endpoint}`

    try {
      const response = await fetch(url, {
        ...options,
        headers: {
          'Content-Type': 'application/json',
          ...options?.headers,
        },
      })

      if (!response.ok) {
        const error: APIError = await response.json().catch(() => ({
          error: 'An error occurred',
          detail: response.statusText,
        }))
        throw new Error(error.error || `HTTP ${response.status}: ${response.statusText}`)
      }

      const json = await response.json()
      // Unwrap {success, data} response if present
      return (json.data || json) as T
    } catch (error) {
      if (error instanceof Error) {
        throw error
      }
      throw new Error('An unexpected error occurred')
    }
  }

  /**
   * Get current weather conditions and flyability assessment
   */
  async getCurrentWeather(
    lat?: number,
    lon?: number
  ): Promise<CurrentWeatherResponse> {
    const params = new URLSearchParams()
    if (lat !== undefined) params.append('lat', lat.toString())
    if (lon !== undefined) params.append('lon', lon.toString())

    const query = params.toString() ? `?${params.toString()}` : ''
    const data = await this.request<any>(`/weather/current${query}`)
    
    // Transform backend response to frontend format
    return {
      location: data.location || { lat: 0, lon: 0 },
      current: {
        timestamp: data.current?.time || data.current?.timestamp,
        wind_speed: data.current?.windSpeed || data.current?.wind_speed || 0,
        wind_direction: data.current?.windDirection || data.current?.wind_direction || 0,
        wind_gust: data.current?.windGust || data.current?.wind_gust || 0,
        temperature: data.current?.temperature || 0,
        cloud_cover: data.current?.cloudCover || data.current?.cloud_cover || 0,
        precipitation: data.current?.precipitation || 0,
        visibility: data.current?.visibility || 0,
        pressure: data.current?.pressure || 0,
        humidity: data.current?.humidity || 0,
      },
      assessment: {
        is_flyable: data.assessment?.FlyableNow || data.assessment?.is_flyable || false,
        reasons: data.assessment?.Reason ? [data.assessment.Reason] : data.assessment?.reasons || [],
        score: data.assessment?.score || 0,
      },
      last_updated: data.timestamp || data.last_updated || new Date().toISOString(),
    }
  }

  /**
   * Get weather forecast for the next 7 days
   */
  async getForecast(
    lat?: number,
    lon?: number
  ): Promise<ForecastResponse> {
    const params = new URLSearchParams()
    if (lat !== undefined) params.append('lat', lat.toString())
    if (lon !== undefined) params.append('lon', lon.toString())

    const query = params.toString() ? `?${params.toString()}` : ''
    const data = await this.request<any>(`/weather/forecast${query}`)
    
    // Transform backend response to frontend format
    return {
      location: data.location || { lat: 0, lon: 0 },
      forecast: (data.forecast || []).map((point: any) => ({
        timestamp: point.Time || point.timestamp,
        wind_speed: point.WindSpeedMPH || point.wind_speed || 0,
        wind_direction: point.WindDirection || point.wind_direction || 0,
        wind_gust: point.WindGustMPH || point.wind_gust || 0,
        temperature: point.temperature || 0,
        cloud_cover: point.cloud_cover || 0,
        precipitation: point.precipitation || 0,
        visibility: point.visibility || 0,
        pressure: point.pressure || 0,
        humidity: point.humidity || 0,
      })),
      flyable_windows: (data.flyableWindows || data.flyable_windows || []).map((win: any) => ({
        start: win.start,
        end: win.end,
        duration_hours: win.durationHours || win.duration_hours || 0,
        avg_conditions: {
          wind_speed: win.avgConditions?.windSpeed || win.avg_conditions?.wind_speed || 0,
          wind_gust: win.avgConditions?.windGust || win.avg_conditions?.wind_gust || 0,
          temperature: win.avgConditions?.temperature || win.avg_conditions?.temperature || 0,
          cloud_cover: win.avgConditions?.cloudCover || win.avg_conditions?.cloud_cover || 0,
        },
      })),
      generated_at: data.generated || data.generated_at || new Date().toISOString(),
    }
  }

  /**
   * Get historical weather data for a specific date
   * @param date - Date in YYYY-MM-DD format
   */
  async getHistorical(
    date: string,
    lat?: number,
    lon?: number
  ): Promise<HistoricalResponse> {
    const params = new URLSearchParams({ date })
    if (lat !== undefined) params.append('lat', lat.toString())
    if (lon !== undefined) params.append('lon', lon.toString())

    const data = await this.request<any>(`/weather/historical?${params.toString()}`)
    
    // Transform backend response to frontend format
    return {
      location: data.location || { lat: 0, lon: 0 },
      date: data.date || date,
      data: (data.data || []).map((point: any) => ({
        timestamp: point.Time || point.timestamp,
        wind_speed: point.WindSpeedMPH || point.wind_speed || 0,
        wind_direction: point.WindDirection || point.wind_direction || 0,
        wind_gust: point.WindGustMPH || point.wind_gust || 0,
        temperature: point.temperature || 0,
        cloud_cover: point.cloud_cover || 0,
        precipitation: point.precipitation || 0,
        visibility: point.visibility || 0,
        pressure: point.pressure || 0,
        humidity: point.humidity || 0,
      })),
    }
  }

  /**
   * Assess current conditions with custom thresholds
   */
  async assessWithThresholds(
    thresholds: Thresholds,
    lat?: number,
    lon?: number
  ): Promise<AssessmentResponse> {
    const params = new URLSearchParams()
    if (lat !== undefined) params.append('lat', lat.toString())
    if (lon !== undefined) params.append('lon', lon.toString())

    const query = params.toString() ? `?${params.toString()}` : ''

    return this.request<AssessmentResponse>(`/weather/assess${query}`, {
      method: 'POST',
      body: JSON.stringify({ thresholds }),
    })
  }
}

// Export singleton instance
export const apiClient = new APIClient(API_BASE_URL)

// Export individual functions for convenience
export const getCurrentWeather = (lat?: number, lon?: number) =>
  apiClient.getCurrentWeather(lat, lon)

export const getForecast = (lat?: number, lon?: number) =>
  apiClient.getForecast(lat, lon)

export const getHistorical = (date: string, lat?: number, lon?: number) =>
  apiClient.getHistorical(date, lat, lon)

export const assessWithThresholds = (
  thresholds: Thresholds,
  lat?: number,
  lon?: number
) => apiClient.assessWithThresholds(thresholds, lat, lon)