import {mkdir} from 'fs-extra';
import tempy from 'tempy';
import execa from 'execa';
import pMapSeries from 'p-map-series';

/**
 * Commit message informations.
 * 
 * @typedef {Object} Commit
 * @property {string} branch The commit branch.
 * @property {string} hash The commit hash.
 * @property {string} message The commit message.
 */

/**
  * Create a temporary git repository and change the current working directory to the repository root.
  *
  * @method gitCommits
  * @param {Array<Commit>} commits the created commits.
  * 
  * @return {string} The path of the repository.
  */
export async function gitRepo() {
  const dir = tempy.directory();

  process.chdir(dir);
  await mkdir('git-templates');
  await execa('git', ['init', '--template=./git-templates']);
  await gitCheckout('master');
  return dir;
}

/**
 * Create commits on the current git repository.
 *
 * @param {Array<string>} messages commit messages.
 * 
 * @returns {Array<Commit>} commits the created commits, in reverse order (to match `git log` order).
 */
export async function gitCommits(messages) {
  return (await pMapSeries(messages, async msg => {
    const {stdout} = await execa('git', ['commit', '-m', msg, '--allow-empty', '--no-gpg-sign']);
    const [, branch, hash, message] = /^\[(\w+)\(?.*?\)?(\w+)\] (.+)$/.exec(stdout);
    return {branch, hash, message};
  })).reverse();
}

/**
 * Checkout a branch on the current git repository.
 *
 * @param {string} branch Branch name.
 * @param {boolean} create `true` to create the branche ans switch, `false` to only switch.
 */
export async function gitCheckout(branch, create = true) {
  await execa('git', ['checkout', create ? '-b' : null, branch]);
}

/**
 * @return {string} The sha of the head commit in the current git repository.
 */
export async function gitHead() {
  return (await execa('git', ['rev-parse', 'HEAD'])).stdout;
}

/**
 * Create a tag on the head commit in the current git repository.
 *
 * @param {string} tagName The tag name to create.
 */
export async function gitTagVersion(tagName) {
  await execa('git', ['tag', tagName]);
}

/**
 * @return {Array<string>} The list of tags from the current git repository.
 */
export async function gitTags() {
  return (await execa('git', ['tag'])).stdout.split('\n').filter(tag => !!tag);
}

/**
 * @return {Array<string>} The list of commit sha from the current git repository.
 */
export async function gitLog() {
  return (await execa('git', ['log', '--format=format:%H'])).stdout.split('\n').filter(sha => !!sha);
}

/**
 * Create a shallow clone of a git repository and change the current working directory to the cloned repository root.
 * The shallow will contain a limited number of commit and no tags.
 * 
 * @param {string} origin The path of the repository to clone.
 * @param {number} [depth=1] The number of commit to clone.
 * @return {string} The path of the cloned repository.
 */
export async function gitShallowClone(origin, depth = 1) {
  const dir = tempy.directory();

  process.chdir(dir);
  await execa('git', ['clone', '--no-hardlinks', '--no-tags', '--depth', depth, `file://${origin}`, dir]);
  return dir;
}

/**
 * Pack heads and tags of the current git repository.
 */
export async function gitPackRefs() {
  await execa('git', ['pack-refs', '--all']);
}