import axios from 'axios';
import { Injectable, Logger } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { RedmineTypes } from '../models/redmine-types';
import { EnhancerService } from '../issue-enhancers/enhancer.service';

@Injectable()
export class RedmineDataLoader {
  urlPrefix: string;

  private logger = new Logger(RedmineDataLoader.name);

  constructor(
    private configService: ConfigService,
    private enhancerService: EnhancerService,
  ) {
    this.urlPrefix = this.configService.get<string>('redmineUrlPrefix');
  }

  async loadIssues(issues: number[]): Promise<(RedmineTypes.Issue | null)[]> {
    const promises = issues.map((issue) => this.loadIssue(issue));
    return Promise.all(promises);
  }

  async loadIssue(issueNumber: number): Promise<RedmineTypes.Issue | null> {
    const url = this.getIssueUrl(issueNumber);
    const resp = await axios.get(url);
    if (!resp || !resp.data || !resp.data.issue) {
      this.logger.error(
        `Failed to load issue from redmine, issueNumber = ${issueNumber}`,
      );
      return null;
    }
    this.logger.debug(
      `Loaded issue, issueNumber = ${issueNumber}, subject = ${resp.data.issue.subject}`,
    );
    return await this.enhancerService.enhanceIssue(resp.data.issue);
  }

  async loadUsers(users: number[]): Promise<(RedmineTypes.User | null)[]> {
    const promises = users.map((user) => this.loadUser(user));
    return Promise.all(promises);
  }

  async loadUser(userNumber: number): Promise<RedmineTypes.User | null> {
    const url = this.getUserUrl(userNumber);
    const resp = await axios.get(url);
    if (!resp || !resp.data?.user) {
      this.logger.error(
        `Failed to load user from redmine, userNumber = ${userNumber}`,
      );
      return null;
    }
    const user: RedmineTypes.User = resp.data.user;
    this.logger.debug(
      `Loaded user, userNumber = ${userNumber}, login = ${user.login}, firstname = ${user.firstname}, lastname = ${user.lastname}`,
    );
    return RedmineTypes.CreateUser(user);
  }

  private getIssueUrl(issueNumber: number): string {
    if (typeof this.urlPrefix !== 'string' || this.urlPrefix.length === 0) {
      throw 'REDMINE_URL_PREFIX is undefined';
    }
    return `${this.urlPrefix}/issues/${issueNumber}.json?include=children,journals,relations`;
  }

  private getUserUrl(userNumber: number): string {
    return `${this.urlPrefix}/users/${userNumber}.json`;
  }
}