feat: pull request backporting

feat: backport still open pull requests

src/service/configs/pullrequest/pr-configs-parser.ts

@@ -0,0 +1,61 @@
+import { Args } from "@bp/service/args/args.types";
+import ConfigsParser from "@bp/service/configs/configs-parser";
+import { Configs } from "@bp/service/configs/configs.types";
+import GitService from "@bp/service/git/git-service";
+import GitServiceFactory from "@bp/service/git/git-service-factory";
+import { GitPullRequest } from "@bp/service/git/git.types";
+
+export default class PullRequestConfigsParser extends ConfigsParser {
+
+  private gitService: GitService;
+
+  constructor() {
+    super();
+    this.gitService = GitServiceFactory.getService();
+  }
+  
+  public async parse(args: Args): Promise<Configs> {
+    const pr: GitPullRequest = await this.gitService.getPullRequestFromUrl(args.pullRequest);
+    const folder: string = args.folder ?? this.getDefaultFolder();
+
+    return {
+      dryRun: args.dryRun,
+      auth: args.auth,
+      author: args.author ?? pr.author,
+      folder: `${folder.startsWith("/") ? "" : process.cwd() + "/"}${args.folder ?? this.getDefaultFolder()}`,
+      targetBranch: args.targetBranch,
+      originalPullRequest: pr,
+      backportPullRequest: this.getDefaultBackportPullRequest(pr, args.targetBranch)
+    };
+  }
+  
+  private getDefaultFolder() {
+    return "bp";
+  }
+
+  /**
+   * Create a default backport pull request starting from the target branch and 
+   * the original pr to be backported
+   * @param originalPullRequest original pull request
+   * @param targetBranch target branch where the backport should be applied
+   * @returns {GitPullRequest}
+   */
+  private getDefaultBackportPullRequest(originalPullRequest: GitPullRequest, targetBranch: string): GitPullRequest {
+    const reviewers = [];
+    reviewers.push(originalPullRequest.author);
+    if (originalPullRequest.mergedBy) {
+      reviewers.push(originalPullRequest.mergedBy);  
+    }
+
+    return {
+      author: originalPullRequest.author,
+      title: `[${targetBranch}] ${originalPullRequest.title}`, 
+      body: `**Backport:** ${originalPullRequest.htmlUrl}\r\n\r\n${originalPullRequest.body}\r\n\r\nPowered by [BPer](https://github.com/lampajr/backporting).`,
+      reviewers: [...new Set(reviewers)],
+      targetRepo: originalPullRequest.targetRepo,
+      sourceRepo: originalPullRequest.targetRepo,
+      nCommits: 0, // TODO: needed?
+      commits: [] // TODO needed?
+    };
+  }
+}