util.ts

import { execute, ExecuteError, type ExecuteOptions } from "./process.ts";

/**
 * A helper function to throw error
 *
 * https://github.com/tc39/proposal-throw-expressions
 */
export function __throw(err: unknown): never {
  throw err;
}

/**
 * Returns a remote name that contains the given commitish.
 *
 * It returns undefined if there is no remote that contains the commitish.
 * If there are multiple remotes that contain the commitish, it prefer to return "origin" or the first one.
 */
export async function getRemoteContains(
  commitish: string,
  options: ExecuteOptions = {},
): Promise<string | undefined> {
  try {
    const branches = (await execute(
      ["branch", "-r", "--contains", commitish, "--format=%(refname:short)"],
      options,
    )).trim().split("\n");
    const remotes = (await execute(["remote"], options)).trim().split("\n");
    const remoteContains = remotes.filter((remote) => {
      return branches.some((branch) => branch.startsWith(`${remote}/`));
    });
    // Prefer "origin" if it exists
    return remoteContains.includes("origin") ? "origin" : remoteContains.at(0);
  } catch (err: unknown) {
    if (err instanceof ExecuteError && err.code === 129) {
      // error: malformed object name ...
      return undefined;
    }
    throw err;
  }
}

/**
 * Returns a remote's fetch URL.
 *
 * It returns undefined if the remote does not exist.
 * If the remote has multiple URLs, it returns the first one.
 */
export async function getRemoteFetchURL(
  remote: string,
  options: ExecuteOptions = {},
): Promise<URL | undefined> {
  try {
    const stdout = await execute(
      ["remote", "get-url", remote],
      options,
    );
    // a remote always has at least one URL
    const url = stdout.trim().split("\n").at(0)!;
    return new URL(url.replace(/^git@([^:]+):(.*)\.git$/, "ssh://git@$1/$2"));
  } catch (err: unknown) {
    if (err instanceof ExecuteError && err.code === 2) {
      // error: No such remote '...'
      return undefined;
    }
    throw err;
  }
}

/**
 * Returns a commit's SHA-1.
 *
 * It returns undefined if the commitish does not exist.
 */
export async function getCommitSHA1(
  commitish: string,
  options: ExecuteOptions = {},
): Promise<string | undefined> {
  try {
    const stdout = await execute(
      ["rev-parse", commitish],
      options,
    );
    return stdout.trim();
  } catch (err: unknown) {
    if (err instanceof ExecuteError && err.code === 128) {
      // ...
      // fatal: ambiguous argument '...': unknown revision or path not in the working tree.
      // Use '--' to separate paths from revisions, like this:
      // 'git <command> [<revision>...] -- [<file>...]'
      return undefined;
    }
    throw err;
  }
}

/**
 * Returns a commit's abbrev ref
 *
 * It returns undefined if the commitish does not exist.
 */
export async function getCommitAbbrevRef(
  commitish: string,
  options: ExecuteOptions = {},
): Promise<string | undefined> {
  try {
    const stdout = await execute(
      ["rev-parse", "--abbrev-ref", commitish],
      options,
    );
    return stdout.trim() || commitish;
  } catch (err: unknown) {
    if (err instanceof ExecuteError && err.code === 128) {
      // ...
      // fatal: ambiguous argument '...': unknown revision or path not in the working tree.
      // Use '--' to separate paths from revisions, like this:
      // 'git <command> [<revision>...] -- [<file>...]'
      return undefined;
    }
    throw err;
  }
}