const gitLogParser = require('git-log-parser');
const getStream = require('get-stream');
const execa = require('execa');
const debug = require('debug')('semantic-release:git');
const {GIT_NOTE_REF} = require('./definitions/constants');

Object.assign(gitLogParser.fields, {hash: 'H', message: 'B', gitTags: 'd', committerDate: {key: 'ci', type: Date}});

/**
 * Get the commit sha for a given tag.
 *
 * @param {String} tagName Tag name for which to retrieve the commit sha.
 * @param {Object} [execaOpts] Options to pass to `execa`.
 *
 * @return {String} The commit sha of the tag in parameter or `null`.
 */
async function getTagHead(tagName, execaOpts) {
  return (await execa('git', ['rev-list', '-1', tagName], execaOpts)).stdout;
}

/**
 * Get all the tags for a given branch.
 *
 * @param {String} branch The branch for which to retrieve the tags.
 * @param {Object} [execaOpts] Options to pass to `execa`.
 *
 * @return {Array<String>} List of git tags.
 * @throws {Error} If the `git` command fails.
 */
async function getTags(branch, execaOpts) {
  return (await execa('git', ['tag', '--merged', branch], execaOpts)).stdout
    .split('\n')
    .map(tag => tag.trim())
    .filter(Boolean);
}

/**
 * Retrieve a range of commits.
 *
 * @param {String} from to includes all commits made after this sha (does not include this sha).
 * @param {String} to to includes all commits made before this sha (also include this sha).
 * @param {Object} [execaOpts] Options to pass to `execa`.
 * @return {Promise<Array<Object>>} The list of commits between `from` and `to`.
 */
async function getCommits(from, to, execaOpts) {
  return (
    await getStream.array(
      gitLogParser.parse(
        {_: `${from ? from + '..' : ''}${to}`},
        {cwd: execaOpts.cwd, env: {...process.env, ...execaOpts.env}}
      )
    )
  ).map(({message, gitTags, ...commit}) => ({...commit, message: message.trim(), gitTags: gitTags.trim()}));
}

/**
 * Get all the repository branches.
 *
 * @param {String} repositoryUrl The remote repository URL.
 * @param {Object} [execaOpts] Options to pass to `execa`.
 *
 * @return {Array<String>} List of git branches.
 * @throws {Error} If the `git` command fails.
 */
async function getBranches(repositoryUrl, execaOpts) {
  return (await execa('git', ['ls-remote', '--heads', repositoryUrl], execaOpts)).stdout
    .split('\n')
    .filter(Boolean)
    .map(branch => branch.match(/^.+refs\/heads\/(?<branch>.+)$/)[1]);
}

/**
 * Verify if the `ref` exits
 *
 * @param {String} ref The reference to verify.
 * @param {Object} [execaOpts] Options to pass to `execa`.
 *
 * @return {Boolean} `true` if the reference exists, falsy otherwise.
 */
async function isRefExists(ref, execaOpts) {
  try {
    return (await execa('git', ['rev-parse', '--verify', ref], execaOpts)).exitCode === 0;
  } catch (error) {
    debug(error);
  }
}

/**
 * Fetch all the tags from a branch. Unshallow if necessary.
 * This will update the local branch from the latest on the remote if:
 * - The branch is not the one that triggered the CI
 * - The CI created a detached head
 *
 * Otherwise it just calls `git fetch` without specifying the `refspec` option to avoid overwritting the head commit set by the CI.
 *
 * The goal is to retrieve the informations on all the release branches without "disturbing" the CI, leaving the trigger branch or the detached head intact.
 *
 * @param {String} repositoryUrl The remote repository URL.
 * @param {String} branch The repository branch to fetch.
 * @param {Object} [execaOpts] Options to pass to `execa`.
 */
async function fetch(repositoryUrl, branch, ciBranch, execaOpts) {
  const isDetachedHead =
    (await execa('git', ['rev-parse', '--abbrev-ref', 'HEAD'], {...execaOpts, reject: false})).stdout === 'HEAD';

  try {
    await execa(
      'git',
      [
        'fetch',
        '--unshallow',
        '--tags',
        ...(branch === ciBranch && !isDetachedHead
          ? [repositoryUrl]
          : ['--update-head-ok', repositoryUrl, `+refs/heads/${branch}:refs/heads/${branch}`]),
      ],
      execaOpts
    );
  } catch (_) {
    await execa(
      'git',
      [
        'fetch',
        '--tags',
        ...(branch === ciBranch && !isDetachedHead
          ? [repositoryUrl]
          : ['--update-head-ok', repositoryUrl, `+refs/heads/${branch}:refs/heads/${branch}`]),
      ],
      execaOpts
    );
  }
}

/**
 * Unshallow the git repository if necessary and fetch all the notes.
 *
 * @param {String} repositoryUrl The remote repository URL.
 * @param {Object} [execaOpts] Options to pass to `execa`.
 */
async function fetchNotes(repositoryUrl, execaOpts) {
  try {
    await execa(
      'git',
      ['fetch', '--unshallow', repositoryUrl, `+refs/notes/${GIT_NOTE_REF}:refs/notes/${GIT_NOTE_REF}`],
      execaOpts
    );
  } catch (_) {
    await execa('git', ['fetch', repositoryUrl, `+refs/notes/${GIT_NOTE_REF}:refs/notes/${GIT_NOTE_REF}`], {
      ...execaOpts,
      reject: false,
    });
  }
}

/**
 * Get the HEAD sha.
 *
 * @param {Object} [execaOpts] Options to pass to `execa`.
 *
 * @return {String} the sha of the HEAD commit.
 */
async function getGitHead(execaOpts) {
  return (await execa('git', ['rev-parse', 'HEAD'], execaOpts)).stdout;
}

/**
 * Get the repository remote URL.
 *
 * @param {Object} [execaOpts] Options to pass to `execa`.
 *
 * @return {string} The value of the remote git URL.
 */
async function repoUrl(execaOpts) {
  try {
    return (await execa('git', ['config', '--get', 'remote.origin.url'], execaOpts)).stdout;
  } catch (error) {
    debug(error);
  }
}

/**
 * Test if the current working directory is a Git repository.
 *
 * @param {Object} [execaOpts] Options to pass to `execa`.
 *
 * @return {Boolean} `true` if the current working directory is in a git repository, falsy otherwise.
 */
async function isGitRepo(execaOpts) {
  try {
    return (await execa('git', ['rev-parse', '--git-dir'], execaOpts)).exitCode === 0;
  } catch (error) {
    debug(error);
  }
}

/**
 * Verify the write access authorization to remote repository with push dry-run.
 *
 * @param {String} repositoryUrl The remote repository URL.
 * @param {String} branch The repository branch for which to verify write access.
 * @param {Object} [execaOpts] Options to pass to `execa`.
 *
 * @throws {Error} if not authorized to push.
 */
async function verifyAuth(repositoryUrl, branch, execaOpts) {
  try {
    await execa('git', ['push', '--dry-run', '--no-verify', repositoryUrl, `HEAD:${branch}`], execaOpts);
  } catch (error) {
    debug(error);
    throw error;
  }
}

/**
 * Tag the commit head on the local repository.
 *
 * @param {String} tagName The name of the tag.
 * @param {String} ref The Git reference to tag.
 * @param {Object} [execaOpts] Options to pass to `execa`.
 *
 * @throws {Error} if the tag creation failed.
 */
async function tag(tagName, ref, execaOpts) {
  await execa('git', ['tag', tagName, ref], execaOpts);
}

/**
 * Push to the remote repository.
 *
 * @param {String} repositoryUrl The remote repository URL.
 * @param {Object} [execaOpts] Options to pass to `execa`.
 *
 * @throws {Error} if the push failed.
 */
async function push(repositoryUrl, execaOpts) {
  await execa('git', ['push', '--tags', repositoryUrl], execaOpts);
}

/**
 * Push notes to the remote repository.
 *
 * @param {String} repositoryUrl The remote repository URL.
 * @param {Object} [execaOpts] Options to pass to `execa`.
 *
 * @throws {Error} if the push failed.
 */
async function pushNotes(repositoryUrl, execaOpts) {
  await execa('git', ['push', repositoryUrl, `refs/notes/${GIT_NOTE_REF}`], execaOpts);
}

/**
 * Verify a tag name is a valid Git reference.
 *
 * @param {String} tagName the tag name to verify.
 * @param {Object} [execaOpts] Options to pass to `execa`.
 *
 * @return {Boolean} `true` if valid, falsy otherwise.
 */
async function verifyTagName(tagName, execaOpts) {
  try {
    return (await execa('git', ['check-ref-format', `refs/tags/${tagName}`], execaOpts)).exitCode === 0;
  } catch (error) {
    debug(error);
  }
}

/**
 * Verify a branch name is a valid Git reference.
 *
 * @param {String} branch the branch name to verify.
 * @param {Object} [execaOpts] Options to pass to `execa`.
 *
 * @return {Boolean} `true` if valid, falsy otherwise.
 */
async function verifyBranchName(branch, execaOpts) {
  try {
    return (await execa('git', ['check-ref-format', `refs/heads/${branch}`], execaOpts)).exitCode === 0;
  } catch (error) {
    debug(error);
  }
}

/**
 * Verify the local branch is up to date with the remote one.
 *
 * @param {String} repositoryUrl The remote repository URL.
 * @param {String} branch The repository branch for which to verify status.
 * @param {Object} [execaOpts] Options to pass to `execa`.
 *
 * @return {Boolean} `true` is the HEAD of the current local branch is the same as the HEAD of the remote branch, falsy otherwise.
 */
async function isBranchUpToDate(repositoryUrl, branch, execaOpts) {
  return (
    (await getGitHead(execaOpts)) ===
    (await execa('git', ['ls-remote', '--heads', repositoryUrl, branch], execaOpts)).stdout.match(/^(?<ref>\w+)?/)[1]
  );
}

/**
 * Get and parse the JSON note of a given reference.
 *
 * @param {String} ref The Git reference for which to retrieve the note.
 * @param {Object} [execaOpts] Options to pass to `execa`.
 *
 * @return {Object} the parsed JSON note if there is one, an empty object otherwise.
 */
async function getNote(ref, execaOpts) {
  try {
    return JSON.parse((await execa('git', ['notes', '--ref', GIT_NOTE_REF, 'show', ref], execaOpts)).stdout);
  } catch (error) {
    if (error.exitCode === 1) {
      return {};
    }

    debug(error);
    throw error;
  }
}

/**
 * Get and parse the JSON note of a given reference.
 *
 * @param {Object} note The object to save in the reference note.
 * @param {String} ref The Git reference to add the note to.
 * @param {Object} [execaOpts] Options to pass to `execa`.
 */
async function addNote(note, ref, execaOpts) {
  await execa('git', ['notes', '--ref', GIT_NOTE_REF, 'add', '-f', '-m', JSON.stringify(note), ref], execaOpts);
}

module.exports = {
  getTagHead,
  getTags,
  getCommits,
  getBranches,
  isRefExists,
  fetch,
  fetchNotes,
  getGitHead,
  repoUrl,
  isGitRepo,
  verifyAuth,
  tag,
  push,
  pushNotes,
  verifyTagName,
  isBranchUpToDate,
  verifyBranchName,
  getNote,
  addNote,
};