import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';

import { ConnectableObservable, Observable } from 'rxjs';
import { map, publishLast } from 'rxjs/operators';

import { Contributor, ContributorGroup } from './contributors.model';

// TODO(andrewjs): Look into changing this so that we don't import the service just to get the const
import { CONTENT_URL_PREFIX } from 'app/documents/document.service';

const contributorsPath = CONTENT_URL_PREFIX + 'contributors.json';
const knownGroups = ['Angular', 'GDE'];

@Injectable()
export class ContributorService {
  contributors: Observable<ContributorGroup[]>;

  constructor(private http: HttpClient) {
    this.contributors = this.getContributors();
  }

  private getContributors() {
    const contributors = this.http.get<{[key: string]: Contributor}>(contributorsPath).pipe(
      // Create group map
      map(contribs => {
        const contribMap: { [name: string]: Contributor[]} = {};
        Object.keys(contribs).forEach(key => {
          const contributor = contribs[key];
          const group = contributor.group;
          const contribGroup = contribMap[group];
          if (contribGroup) {
            contribGroup.push(contributor);
          } else {
            contribMap[group] = [contributor];
          }
        });

        return contribMap;
      }),

      // Flatten group map into sorted group array of sorted contributors
      map(cmap => {
        return Object.keys(cmap).map(key => {
          const order = knownGroups.indexOf(key);
          return {
            name: key,
            order: order === -1 ? knownGroups.length : order,
            contributors: cmap[key].sort(compareContributors)
          } as ContributorGroup;
        })
        .sort(compareGroups);
      }),

      publishLast(),
    );

    (contributors as ConnectableObservable<ContributorGroup[]>).connect();
    return contributors;
  }
}

function compareContributors(l: Contributor, r: Contributor) {
 return l.name.toUpperCase() > r.name.toUpperCase() ? 1 : -1;
}

function compareGroups(l: ContributorGroup, r: ContributorGroup) {
  return l.order === r.order ?
    (l.name > r.name ? 1 : -1) :
     l.order > r.order ? 1 : -1;
}
