import {Injectable} from '@angular/core';
import {HttpClient} from '@angular/common/http';
import {AppConfig} from '../shared/app.config';
import {Observable} from 'rxjs';
import {WeatherCurrentObservation} from '../models/weatherCurrentObservation';
import {DatePipe} from '@angular/common';
import {WeatherData} from '../models/WeatherData';
import {GeoJSON} from 'ol/format';
import {map, switchMap} from 'rxjs/operators';
import {getCenter} from 'ol/extent';
import {IItem} from '../models/item';

@Injectable({
  providedIn: 'root',
})
export class WeatherService {
  private apiCurrentObservationUrl = 'currentobservation';
  private apiObservation = 'observation';
  private apiForecast = 'forecast';

  private format: GeoJSON;

  constructor(public httpClient: HttpClient, public appConfig: AppConfig, private datePipe: DatePipe) {
    this.format = new GeoJSON();
  }

  public GetCurrentObservation(centroid: number[]): Observable<WeatherCurrentObservation> {
    const endpoint = this.appConfig.getConfig('weatherApiEndPoint');
    const apiKey = this.appConfig.getConfig('weatherApiKey');
    const observationUrl = `${endpoint}${this.apiCurrentObservationUrl}/?c=${centroid[0]},${centroid[1]}&key=${apiKey}`;

    return this.httpClient.get<WeatherCurrentObservation>(observationUrl);
  }

  public getWeatherRangeForItem(item: IItem, daysBefore = 10, daysAfter = 10): Observable<WeatherData[]> {
    const geometry = this.format.readGeometry(item.geometry);
    const centroid = getCenter(geometry.getExtent());

    const currentDate = new Date(Date.now());
    const sd = new Date(Date.now());
    const ed = new Date(Date.now());
    sd.setDate((currentDate.getDate() - daysBefore));
    ed.setDate((currentDate.getDate() + daysAfter));

    return this.getWeatherRange(centroid, this.datePipe.transform(sd, 'yyyy-MM-ddThh:mm:ss'),
      this.datePipe.transform(ed, 'yyyy-MM-ddThh:mm:ss'));
  }

  public getWeatherRange(centroid: number[], startDate: string, endDate: string): Observable<WeatherData[]> {
    const endpoint = this.appConfig.getConfig('weatherApiEndPoint');
    const apiKey = this.appConfig.getConfig('weatherApiKey');

    // weather does not support UTC format, also remove Z
    const sd = encodeURIComponent(this.removeUTCZ(startDate));
    const ed = encodeURIComponent(this.removeUTCZ(endDate));

    const historical = `${endpoint}${this.apiObservation}/?c=${centroid[0]},${centroid[1]}&sd=${sd}&ed=${ed}&interval=daily&key=${apiKey}`;
    const forecast = `${endpoint}${this.apiForecast}/?c=${centroid[0]},${centroid[1]}&interval=daily&key=${apiKey}`;

    return this.httpClient.get<any[]>(historical).pipe(
      map(h => h.map(this.createWeatherDataFromHistorical)),
      switchMap(h => {
        return this.httpClient.get<any[]>(forecast)
          .pipe(
            map(f => [...h, ...f.filter(fd => fd.date <= endDate)
              .map(this.createWeatherDataFromForecast)]));
      })
    );
  }

  private createWeatherDataFromHistorical(hd): WeatherData {
    return {time: hd.date, minTemp: hd.minimumTemperature,
      maxTemp: hd.maximumTemperature, relativeHumidity: hd.relativeHumidity, rain: hd.precipitation};
  }

  private createWeatherDataFromForecast(fd): WeatherData {
    return {time: fd.date, minTemp: fd.minimumTemperature,
      maxTemp: fd.maximumTemperature, relativeHumidity: fd.relativeHumidity, rain: fd.rain};
  }

  private removeUTCZ(dateFormat: string): string {
    if (dateFormat[dateFormat.length - 1] === 'Z') {
      return dateFormat.substring(0, dateFormat.length - 1);
    }

    return dateFormat;
  }
}