chartData.ts

import * as moment from 'moment';
import { Injectable } from '@angular/core';
import { isArray } from 'ionic-angular/util/util';
import { ReplaySubject, Observable } from 'rxjs';
import { ChartData, ChartDataSets } from 'chart.js';

import { Profile } from './../../models/profile/profile';
import { Report } from './../../models/report/report';
import { ReportProvider } from './../report/report';
import { ProfileProvider } from './../profile/profile';


@Injectable()
export class ChartsProvider {
  private activeProfile: Profile
  private  _chartData: ReplaySubject<any> = new ReplaySubject<any>(1)
  private  _profileResume: ReplaySubject<any> = new ReplaySubject<any>(1)
  constructor(
    private profileProvider: ProfileProvider,
    private reportProvider: ReportProvider
  ) {
    let data = profileProvider.activeProfile()
    .do(next => this.activeProfile = next )
    .switchMap(_data => this.reportProvider.allFor(_data))

    data.map(_data => this.linePerDay(_data))
    .subscribe(_data => {
      this._chartData.next(_data)
    })
  }

  private linePerDay(reports: Report[]) {
    const complete: any = {}
    let indexator    = (x: Report) => x.values.date
    let selectedItem  = (x: Report) => x.values.triggers.map(x => x.name)
    let _label: any[] = reports.map( x => indexator(x))
    .filter((item, index, array) => array.indexOf(item) == index)
    .map(x => moment(x).format("DD/MM YY") )
    let _dataset: any[] = this.prepareDataset(reports)
    complete.labels = _label
    complete.datasets = _dataset
    return complete
  }
  private prepareDataset(reports: Report[]) {
    const sortedReports = reports.sort((left, right) => {
      return moment.utc(left.values.date).diff(moment.utc(right.values.date))
    })
    let dataset: ChartDataSets[] = []
    let perDay: Object = this.reportsPerDay(sortedReports)
    let newData: any[] = Array()
    for (const key in perDay) {
      if (perDay.hasOwnProperty(key)) {
        const element = perDay[key];
        newData.push(element)
      }
    }
    dataset.push({
      data: newData,
      label: 'Casos diários',
      borderColor: `rgba(${this.rgbaCode()},${this.rgbaCode()},${this.rgbaCode()},${this.rgbaCode()})`,
      fill: false
    })
    return dataset
  }
  private reportsPerDay(reports: Report[]): Object {
    let _data = reports.map(report => report.values.date)
    .reduce((count, cur) => {
      count[cur] = ++count[cur] || 1 
      return count
    }, {})
    return _data
  }
  public lineChart(): Observable<any> {
    return new Observable((subject) => {
      this._chartData.subscribe((next) => {
        subject.next(next)
      }, (err) => {
        subject.error(err)
      }, () => {
        subject.complete()
      })
    })
  }
  public profileResume(): Observable<any[]> {
    return new Observable((subject) => {
      this._profileResume.subscribe((next: any[]) => {
        subject.next(next)
      }, (err) => {
        subject.error(err)
      }, () => {
        subject.complete()
      })
    })
  }
  private rgbaCode() {
    return Math.floor(Math.random() * (1 - 255 + 1)) + 255;
  }
}