import simpleGit from "simple-git";

export async function getBranchName(): Promise<string> {
  const git = simpleGit();
  const revParseResponse = await git.revparse(["--abbrev-ref", "HEAD"]);
  return revParseResponse;
}

export async function getCurrentCommitHash(): Promise<string> {
  const git = simpleGit();
  const revParseResponse = await git.revparse("HEAD");
  return revParseResponse;
}

export async function getBaseCommitHash(): Promise<string> {
  const git = simpleGit({ trimmed: true });

  const defaultBranch = await getDefaultBranch();
  const currentCommit = await getCurrentCommitHash();

  const baseCommitHash = await git.raw([
    "merge-base",
    defaultBranch,
    currentCommit,
  ]);
  return baseCommitHash;
}

export async function getDefaultBranch(): Promise<string> {
  // TODO: Might need to make it more generic in the future
  return "main";
}

async function getLatestMainBranchCommitHashes(): Promise<string[]> {
  const git = simpleGit({ trimmed: true });

  const rawLatestCommits = await git.raw([
    "--no-pager",
    "log",
    await getDefaultBranch(),
    "--decorate=short",
    "--format=%H",
    "-n",
    "100",
  ]);

  return rawLatestCommits
    .split("\n")
    .map((line) => line.trim())
    .filter((line) => line.length > 0);
}

export async function getLatestBaseCommitHashes(): Promise<string[]> {
  const baseCommit = await getBaseCommitHash();
  const latestMainCommits = await getLatestMainBranchCommitHashes();

  const baseIndex = latestMainCommits.findIndex(
    (commit) => commit === baseCommit
  );
  if (baseIndex < 0) {
    console.error(
      `base commit '${baseCommit}' could not be found in the latestMainCommits:`,
      latestMainCommits
    );
    throw new Error("unable to determine latest base commits");
  }

  return latestMainCommits.slice(baseIndex, baseIndex + 30);
}