import { UrlParamFilterService } from './url-param-filter.service';
import { UrlParamSortService } from './url-param-sort.service';
import { UrlParamPageService } from './url-param-page.service';

export class UrlParamBuilderService {

  public constructor(
    private urlParamFilterService: UrlParamFilterService,
    private urlParamSortService: UrlParamSortService,
    private urlParamPageService: UrlParamPageService
  ) {}

  public build(filters?: {[key: string]: any}, sort?: string[], page?: number, limit?: number): string {
    const combinedParams: {[key: string]: string|string[]|number} = {};

    const sorting: {sort: string|string[]} = this.urlParamSortService.urlEncode(sort);
    const paging: {page: number, limit: number} = this.urlParamPageService.urlEncode(page, limit);
    const filter: {[key: string]: string|string[]} = this.urlParamFilterService.urlEncode(filters);

    for (const key in filter) {
      if (filter[key]) {
        combinedParams[key] = filter[key];
      }
    }
    combinedParams['sort'] = sorting.sort;
    combinedParams['page'] = paging.page;
    combinedParams['limit'] = paging.limit;

    return this.buildQueryString(combinedParams);
  }

  private buildQueryString(params: {[key: string]: string|string[]|number}): string {
    const items: string[] = [];
    Object.keys(params).forEach((key: string) => {
      const value: any = params[key];

      if (value.constructor === Array) {
        const valueParams: string[] = [];
        value.forEach((valueItem: any) => {
          valueParams.push(key + '[]=' + valueItem);
        });
        items.push(valueParams.join('&'));
      } else {
        items.push(key + '=' + value);
      }
    });
    return items.join('&');
  }

}