<?php

/*
 * Copyright 2012 Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Interfaces with the VCS in the working copy.
 *
 * @group workingcopy
 */
abstract class ArcanistRepositoryAPI {

  const FLAG_MODIFIED     = 1;
  const FLAG_ADDED        = 2;
  const FLAG_DELETED      = 4;
  const FLAG_UNTRACKED    = 8;
  const FLAG_CONFLICT     = 16;
  const FLAG_MISSING      = 32;
  const FLAG_UNSTAGED     = 64;
  const FLAG_UNCOMMITTED  = 128;
  const FLAG_EXTERNALS    = 256;

  // Occurs in SVN when you replace a file with a directory without telling
  // SVN about it.
  const FLAG_OBSTRUCTED   = 512;

  // Occurs in SVN when an update was interrupted or failed, e.g. you ^C'd it.
  const FLAG_INCOMPLETE   = 1024;

  protected $path;
  protected $diffLinesOfContext = 0x7FFF;
  private $workingCopyIdentity;

  abstract public function getSourceControlSystemName();

  public function getDiffLinesOfContext() {
    return $this->diffLinesOfContext;
  }

  public function setDiffLinesOfContext($lines) {
    $this->diffLinesOfContext = $lines;
    return $this;
  }

  public function getWorkingCopyIdentity() {
    return $this->workingCopyIdentity;
  }

  public static function newAPIFromWorkingCopyIdentity(
    ArcanistWorkingCopyIdentity $working_copy) {

    $root = $working_copy->getProjectRoot();

    if (!$root) {
      throw new ArcanistUsageException(
        "There is no readable '.arcconfig' file in the working directory or ".
        "any parent directory. Create an '.arcconfig' file to configure arc.");
    }

    // check if we're in an svn working copy
    list($err) = exec_manual('svn info');
    if (!$err) {
      $api = newv('ArcanistSubversionAPI', array($root));
      $api->workingCopyIdentity = $working_copy;
      return $api;
    }

    if (Filesystem::pathExists($root.'/.hg')) {
      $api = newv('ArcanistMercurialAPI', array($root));
      $api->workingCopyIdentity = $working_copy;
      return $api;
    }

    $git_root = self::discoverGitBaseDirectory($root);
    if ($git_root) {
      if (!Filesystem::pathsAreEquivalent($root, $git_root)) {
        throw new ArcanistUsageException(
          "'.arcconfig' file is located at '{$root}', but working copy root ".
          "is '{$git_root}'. Move '.arcconfig' file to the working copy root.");
      }

      $api = newv('ArcanistGitAPI', array($root));
      $api->workingCopyIdentity = $working_copy;
      return $api;
    }

    throw new ArcanistUsageException(
      "The current working directory is not part of a working copy for a ".
      "supported version control system (svn, git or mercurial).");
  }

  public function __construct($path) {
    $this->path = $path;
  }

  public function getPath($to_file = null) {
    if ($to_file !== null) {
      return $this->path.DIRECTORY_SEPARATOR.
             ltrim($to_file, DIRECTORY_SEPARATOR);
    } else {
      return $this->path.DIRECTORY_SEPARATOR;
    }
  }

  public function getUntrackedChanges() {
    return $this->getWorkingCopyFilesWithMask(self::FLAG_UNTRACKED);
  }

  public function getUnstagedChanges() {
    return $this->getWorkingCopyFilesWithMask(self::FLAG_UNSTAGED);
  }

  public function getUncommittedChanges() {
    return $this->getWorkingCopyFilesWithMask(self::FLAG_UNCOMMITTED);
  }

  public function getMergeConflicts() {
    return $this->getWorkingCopyFilesWithMask(self::FLAG_CONFLICT);
  }

  public function getIncompleteChanges() {
    return $this->getWorkingCopyFilesWithMask(self::FLAG_INCOMPLETE);
  }

  private function getWorkingCopyFilesWithMask($mask) {
    $match = array();
    foreach ($this->getWorkingCopyStatus() as $file => $flags) {
      if ($flags & $mask) {
        $match[] = $file;
      }
    }
    return $match;
  }

  private static function discoverGitBaseDirectory($root) {
    try {

      // NOTE: This awkward construction is to make sure things work on Windows.
      $future = new ExecFuture('git rev-parse --show-cdup');
      $future->setCWD($root);
      list($stdout) = $future->resolvex();

      return Filesystem::resolvePath(rtrim($stdout, "\n"), $root);
    } catch (CommandException $ex) {
      if (preg_match('/^fatal: Not a git repository/', $ex->getStdErr())) {
        return null;
      }
      throw $ex;
    }
  }

  abstract public function getBlame($path);
  abstract public function getWorkingCopyStatus();
  abstract public function getRawDiffText($path);
  abstract public function getOriginalFileData($path);
  abstract public function getCurrentFileData($path);
  abstract public function getLocalCommitInformation();
  abstract public function getSourceControlBaseRevision();
  abstract public function getCanonicalRevisionName($string);
  abstract public function supportsRelativeLocalCommits();
  abstract public function getWorkingCopyRevision();
  abstract public function updateWorkingCopy();
  abstract public function loadWorkingCopyDifferentialRevisions(
    ConduitClient $conduit,
    array $query);

  public function hasLocalCommit($commit) {
    throw new ArcanistCapabilityNotSupportedException($this);
  }

  public function getCommitMessageForRevision($revision) {
    throw new ArcanistCapabilityNotSupportedException($this);
  }

  public function parseRelativeLocalCommit(array $argv) {
    throw new ArcanistCapabilityNotSupportedException($this);
  }

  public function getAllLocalChanges() {
    throw new ArcanistCapabilityNotSupportedException($this);
  }

  abstract public function supportsLocalBranchMerge();

  public function performLocalBranchMerge($branch, $message) {
    throw new ArcanistCapabilityNotSupportedException($this);
  }

  public function getFinalizedRevisionMessage() {
    throw new ArcanistCapabilityNotSupportedException($this);
  }

  public function execxLocal($pattern /*, ... */) {
    $args = func_get_args();
    return $this->buildLocalFuture($args)->resolvex();
  }

  public function execManualLocal($pattern /*, ... */) {
    $args = func_get_args();
    return $this->buildLocalFuture($args)->resolve();
  }

  public function execFutureLocal($pattern /*, ... */) {
    $args = func_get_args();
    return $this->buildLocalFuture($args);
  }

  abstract protected function buildLocalFuture(array $argv);


/* -(  Scratch Files  )------------------------------------------------------ */


  /**
   * Try to read a scratch file, if it exists and is readable.
   *
   * @param string Scratch file name.
   * @return mixed String for file contents, or false for failure.
   * @task scratch
   */
  public function readScratchFile($path) {
    $full_path = $this->getScratchFilePath($path);
    if (!$full_path) {
      return false;
    }

    if (!Filesystem::pathExists($full_path)) {
      return false;
    }

    try {
      $result = Filesystem::readFile($full_path);
    } catch (FilesystemException $ex) {
      return false;
    }

    return $result;
  }


  /**
   * Try to write a scratch file, if there's somewhere to put it and we can
   * write there.
   *
   * @param  string Scratch file name to write.
   * @param  string Data to write.
   * @return bool   True on success, false on failure.
   * @task scratch
   */
  public function writeScratchFile($path, $data) {
    $dir = $this->getScratchFilePath('');
    if (!$dir) {
      return false;
    }

    if (!Filesystem::pathExists($dir)) {
      try {
        Filesystem::createDirectory($dir);
      } catch (Exception $ex) {
        return false;
      }
    }

    try {
      Filesystem::writeFile($this->getScratchFilePath($path), $data);
    } catch (FilesystemException $ex) {
      return false;
    }

    return true;
  }


  /**
   * Try to remove a scratch file.
   *
   * @param   string  Scratch file name to remove.
   * @return  bool    True if the file was removed successfully.
   * @task scratch
   */
  public function removeScratchFile($path) {
    $full_path = $this->getScratchFilePath($path);
    if (!$full_path) {
      return false;
    }

    try {
      Filesystem::remove($full_path);
    } catch (FilesystemException $ex) {
      return false;
    }

    return true;
  }


  /**
   * Get a human-readable description of the scratch file location.
   *
   * @param string  Scratch file name.
   * @return mixed  String, or false on failure.
   * @task scratch
   */
  public function getReadableScratchFilePath($path) {
    $full_path = $this->getScratchFilePath($path);
    if ($full_path) {
      return Filesystem::readablePath(
        $full_path,
        $this->getPath());
    } else {
      return false;
    }
  }


  /**
   * Get the path to a scratch file, if possible.
   *
   * @param string  Scratch file name.
   * @return mixed  File path, or false on failure.
   * @task scratch
   */
  public function getScratchFilePath($path) {
    return $this->getPath('.arc/'.$path);
  }

}