import type { Repository } from "../../../packages/shared/src/types";

export async function createGitLabMergeRequest(
  repo: Repository,
  sourceBranch: string,
  targetBranch: string,
  title: string,
  description: string,
): Promise<string> {
  if (!repo.gitlab_host) {
    throw new Error("Repository missing gitlab_host");
  }
  if (!repo.access_token) {
    throw new Error("Repository missing access_token");
  }

  const encodedId = encodeURIComponent(repo.full_name);
  const url = `https://${repo.gitlab_host}/api/v4/projects/${encodedId}/merge_requests`;

  const res = await fetch(url, {
    method: "POST",
    headers: {
      "PRIVATE-TOKEN": repo.access_token,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      source_branch: sourceBranch,
      target_branch: targetBranch,
      title,
      description,
    }),
  });

  if (!res.ok) {
    const text = await res.text();
    throw new Error(`GitLab create MR failed: ${res.status} ${text}`);
  }

  const data = (await res.json()) as { web_url: string };
  try {
    const urlObj = new URL(data.web_url);
    urlObj.hostname = repo.gitlab_host;
    return urlObj.toString();
  } catch {
    return data.web_url;
  }
}