<?php

/**
 * Interfaces with the Mercurial working copies.
 *
 * @group workingcopy
 */
final class ArcanistMercurialAPI extends ArcanistRepositoryAPI {

  private $status;
  private $base;
  private $relativeCommit;
  private $branch;
  private $workingCopyRevision;
  private $localCommitInfo;
  private $includeDirectoryStateInDiffs;

  protected function buildLocalFuture(array $argv) {

    // Mercurial has a "defaults" feature which basically breaks automation by
    // allowing the user to add random flags to any command. This feature is
    // "deprecated" and "a bad idea" that you should "forget ... existed"
    // according to project lead Matt Mackall:
    //
    //  http://markmail.org/message/hl3d6eprubmkkqh5
    //
    // There is an HGPLAIN environmental variable which enables "plain mode"
    // and hopefully disables this stuff.

    if (phutil_is_windows()) {
      $argv[0] = 'set HGPLAIN=1 & hg '.$argv[0];
    } else {
      $argv[0] = 'HGPLAIN=1 hg '.$argv[0];
    }

    $future = newv('ExecFuture', $argv);
    $future->setCWD($this->getPath());
    return $future;
  }

  public function getSourceControlSystemName() {
    return 'hg';
  }

  public function getMetadataPath() {
    return $this->getPath('.hg');
  }

  public function getSourceControlBaseRevision() {
    return $this->getCanonicalRevisionName($this->getRelativeCommit());
  }

  public function getCanonicalRevisionName($string) {
    list($stdout) = $this->execxLocal(
      'log -l 1 --template %s -r %s --',
      '{node}',
      $string);
    return $stdout;
  }

  public function getSourceControlPath() {
    return '/';
  }

  public function getBranchName() {
    if (!$this->branch) {
      list($stdout) = $this->execxLocal('branch');
      $this->branch = trim($stdout);
    }
    return $this->branch;
  }

  public function setRelativeCommit($commit) {
    try {
      $commit = $this->getCanonicalRevisionName($commit);
    } catch (Exception $ex) {
      throw new ArcanistUsageException(
        "Commit '{$commit}' is not a valid Mercurial commit identifier.");
    }

    $this->relativeCommit = $commit;
    $this->status = null;
    $this->localCommitInfo = null;

    return $this;
  }

  public function getRelativeCommit() {
    if (empty($this->relativeCommit)) {

      if ($this->getBaseCommitArgumentRules() ||
          $this->getWorkingCopyIdentity()->getConfigFromAnySource('base')) {
        $base = $this->resolveBaseCommit();
        if (!$base) {
          throw new ArcanistUsageException(
            "None of the rules in your 'base' configuration matched a valid ".
            "commit. Adjust rules or specify which commit you want to use ".
            "explicitly.");
        }
        $this->relativeCommit = $base;
        return $this->relativeCommit;
      }

      list($err, $stdout) = $this->execManualLocal(
        'outgoing --branch %s --style default',
        $this->getBranchName());

      if (!$err) {
        $logs = ArcanistMercurialParser::parseMercurialLog($stdout);
      } else {
        // Mercurial (in some versions?) raises an error when there's nothing
        // outgoing.
        $logs = array();
      }

      if (!$logs) {

        $this->setBaseCommitExplanation(
          "you have no outgoing commits, so arc assumes you intend to submit ".
          "uncommitted changes in the working copy.");
        // In Mercurial, we support operations against uncommitted changes.
        $this->setRelativeCommit($this->getWorkingCopyRevision());
        return $this->relativeCommit;
      }

      $outgoing_revs = ipull($logs, 'rev');

      // This is essentially an implementation of a theoretical `hg merge-base`
      // command.
      $against = $this->getWorkingCopyRevision();
      while (true) {
        // NOTE: The "^" and "~" syntaxes were only added in hg 1.9, which is
        // new as of July 2011, so do this in a compatible way. Also, "hg log"
        // and "hg outgoing" don't necessarily show parents (even if given an
        // explicit template consisting of just the parents token) so we need
        // to separately execute "hg parents".

        list($stdout) = $this->execxLocal(
          'parents --style default --rev %s',
          $against);
        $parents_logs = ArcanistMercurialParser::parseMercurialLog($stdout);

        list($p1, $p2) = array_merge($parents_logs, array(null, null));

        if ($p1 && !in_array($p1['rev'], $outgoing_revs)) {
          $against = $p1['rev'];
          break;
        } else if ($p2 && !in_array($p2['rev'], $outgoing_revs)) {
          $against = $p2['rev'];
          break;
        } else if ($p1) {
          $against = $p1['rev'];
        } else {
          // This is the case where you have a new repository and the entire
          // thing is outgoing; Mercurial literally accepts "--rev null" as
          // meaning "diff against the empty state".
          $against = 'null';
          break;
        }
      }

      if ($against == 'null') {
        $this->setBaseCommitExplanation(
          "this is a new repository (all changes are outgoing).");
      } else {
        $this->setBaseCommitExplanation(
          "it is the first commit reachable from the working copy state ".
          "which is not outgoing.");
      }

      $this->setRelativeCommit($against);
    }
    return $this->relativeCommit;
  }

  public function getLocalCommitInformation() {
    if ($this->localCommitInfo === null) {
      list($info) = $this->execxLocal(
        "log --template '%C' --rev %s --branch %s --",
        "{node}\1{rev}\1{author}\1{date|rfc822date}\1".
          "{branch}\1{tag}\1{parents}\1{desc}\2",
        '(ancestors(.) - ancestors('.$this->getRelativeCommit().'))',
        $this->getBranchName());
      $logs = array_filter(explode("\2", $info));

      $last_node = null;

      $futures = array();

      $commits = array();
      foreach ($logs as $log) {
        list($node, $rev, $author, $date, $branch, $tag, $parents, $desc) =
          explode("\1", $log);

        // NOTE: If a commit has only one parent, {parents} returns empty.
        // If it has two parents, {parents} returns revs and short hashes, not
        // full hashes. Try to avoid making calls to "hg parents" because it's
        // relatively expensive.
        $commit_parents = null;
        if (!$parents) {
          if ($last_node) {
            $commit_parents = array($last_node);
          }
        }

        if (!$commit_parents) {
          // We didn't get a cheap hit on previous commit, so do the full-cost
          // "hg parents" call. We can run these in parallel, at least.
          $futures[$node] = $this->execFutureLocal(
            "parents --template='{node}\\n' --rev %s",
            $node);
        }

        $commits[$node] = array(
          'author'  => $author,
          'time'    => strtotime($date),
          'branch'  => $branch,
          'tag'     => $tag,
          'commit'  => $node,
          'rev'     => $node, // TODO: Remove eventually.
          'local'   => $rev,
          'parents' => $commit_parents,
          'summary' => head(explode("\n", $desc)),
          'message' => $desc,
        );

        $last_node = $node;
      }

      foreach (Futures($futures)->limit(4) as $node => $future) {
        list($parents) = $future->resolvex();
        $parents = array_filter(explode("\n", $parents));
        $commits[$node]['parents'] = $parents;
      }

      // Put commits in newest-first order, to be consistent with Git and the
      // expected order of "hg log" and "git log" under normal circumstances.
      // The order of ancestors() is oldest-first.
      $commits = array_reverse($commits);

      $this->localCommitInfo = $commits;
    }

    return $this->localCommitInfo;
  }

  public function getBlame($path) {
    list($stdout) = $this->execxLocal(
      'annotate -u -v -c --rev %s -- %s',
      $this->getRelativeCommit(),
      $path);

    $blame = array();
    foreach (explode("\n", trim($stdout)) as $line) {
      if (!strlen($line)) {
        continue;
      }

      $matches = null;
      $ok = preg_match('/^\s*([^:]+?) [a-f0-9]{12}: (.*)$/', $line, $matches);

      if (!$ok) {
        throw new Exception("Unable to parse Mercurial blame line: {$line}");
      }

      $revision = $matches[2];
      $author = trim($matches[1]);
      $blame[] = array($author, $revision);
    }

    return $blame;
  }

  public function getWorkingCopyStatus() {

    if (!isset($this->status)) {
      // A reviewable revision spans multiple local commits in Mercurial, but
      // there is no way to get file change status across multiple commits, so
      // just take the entire diff and parse it to figure out what's changed.

      $diff = $this->getFullMercurialDiff();

      if (!$diff) {
        $this->status = array();
        return $this->status;
      }

      $parser = new ArcanistDiffParser();
      $changes = $parser->parseDiff($diff);

      $status_map = array();

      foreach ($changes as $change) {
        $flags = 0;
        switch ($change->getType()) {
          case ArcanistDiffChangeType::TYPE_ADD:
          case ArcanistDiffChangeType::TYPE_MOVE_HERE:
          case ArcanistDiffChangeType::TYPE_COPY_HERE:
            $flags |= self::FLAG_ADDED;
            break;
          case ArcanistDiffChangeType::TYPE_CHANGE:
          case ArcanistDiffChangeType::TYPE_COPY_AWAY: // Check for changes?
            $flags |= self::FLAG_MODIFIED;
            break;
          case ArcanistDiffChangeType::TYPE_DELETE:
          case ArcanistDiffChangeType::TYPE_MOVE_AWAY:
          case ArcanistDiffChangeType::TYPE_MULTICOPY:
            $flags |= self::FLAG_DELETED;
            break;
        }
        $status_map[$change->getCurrentPath()] = $flags;
      }

      list($stdout) = $this->execxLocal('status');

      $working_status = ArcanistMercurialParser::parseMercurialStatus($stdout);
      foreach ($working_status as $path => $status) {
        if ($status & ArcanistRepositoryAPI::FLAG_UNTRACKED) {
          // If the file is untracked, don't mark it uncommitted.
          continue;
        }
        $status |= self::FLAG_UNCOMMITTED;
        if (!empty($status_map[$path])) {
          $status_map[$path] |= $status;
        } else {
          $status_map[$path] = $status;
        }
      }

      $this->status = $status_map;
    }

    return $this->status;
  }

  private function getDiffOptions() {
    $options = array(
      '--git',
      '-U'.$this->getDiffLinesOfContext(),
    );
    return implode(' ', $options);
  }

  public function getRawDiffText($path) {
    $options = $this->getDiffOptions();

    // NOTE: In Mercurial, "--rev x" means "diff between x and the working
    // copy state", while "--rev x..." means "diff between x and the working
    // copy commit" (i.e., from 'x' to '.'). The latter excludes any dirty
    // changes in the working copy.

    $range = $this->getRelativeCommit();
    if (!$this->includeDirectoryStateInDiffs) {
      $range .= '...';
    }

    list($stdout) = $this->execxLocal(
      'diff %C --rev %s -- %s',
      $options,
      $range,
      $path);

    return $stdout;
  }

  public function getFullMercurialDiff() {
    return $this->getRawDiffText('');
  }

  public function getOriginalFileData($path) {
    return $this->getFileDataAtRevision($path, $this->getRelativeCommit());
  }

  public function getCurrentFileData($path) {
    return $this->getFileDataAtRevision(
      $path,
      $this->getWorkingCopyRevision());
  }

  private function getFileDataAtRevision($path, $revision) {
    list($err, $stdout) = $this->execManualLocal(
      'cat --rev %s -- %s',
      $revision,
      $path);
    if ($err) {
      // Assume this is "no file at revision", i.e. a deleted or added file.
      return null;
    } else {
      return $stdout;
    }
  }

  public function getWorkingCopyRevision() {
    return '.';
  }

  public function isHistoryDefaultImmutable() {
    return true;
  }

  public function supportsAmend() {
    list($err, $stdout) = $this->execManualLocal('help commit');
    if ($err) {
      return false;
    } else {
      return (strpos($stdout, "amend") !== false);
    }
  }

  public function supportsRelativeLocalCommits() {
    return true;
  }

  public function setDefaultBaseCommit() {
    $this->setRelativeCommit('.^');
    return $this;
  }

  public function hasLocalCommit($commit) {
    try {
      $this->getCanonicalRevisionName($commit);
      return true;
    } catch (Exception $ex) {
      return false;
    }
  }

  public function getCommitMessage($commit) {
    list($message) = $this->execxLocal(
      'log --template={desc} --rev %s',
      $commit);
    return $message;
  }

  public function parseRelativeLocalCommit(array $argv) {
    if (count($argv) == 0) {
      return;
    }
    if (count($argv) != 1) {
      throw new ArcanistUsageException("Specify only one commit.");
    }

    $this->setBaseCommitExplanation("you explicitly specified it.");

    // This does the "hg id" call we need to normalize/validate the revision
    // identifier.
    $this->setRelativeCommit(reset($argv));
  }

  public function getAllLocalChanges() {
    $diff = $this->getFullMercurialDiff();
    if (!strlen(trim($diff))) {
      return array();
    }
    $parser = new ArcanistDiffParser();
    return $parser->parseDiff($diff);
  }

  public function supportsLocalBranchMerge() {
    return true;
  }

  public function performLocalBranchMerge($branch, $message) {
    if ($branch) {
      $err = phutil_passthru(
        '(cd %s && HGPLAIN=1 hg merge --rev %s && hg commit -m %s)',
        $this->getPath(),
        $branch,
        $message);
    } else {
      $err = phutil_passthru(
        '(cd %s && HGPLAIN=1 hg merge && hg commit -m %s)',
        $this->getPath(),
        $message);
    }

    if ($err) {
      throw new ArcanistUsageException("Merge failed!");
    }
  }

  public function getFinalizedRevisionMessage() {
    return "You may now push this commit upstream, as appropriate (e.g. with ".
           "'hg push' or by printing and faxing it).";
  }

  public function getCommitMessageLog() {
    list($stdout) = $this->execxLocal(
      "log --template '{node}\\2{desc}\\1' --rev %s --branch %s --",
      'ancestors(.) - ancestors('.$this->getRelativeCommit().')',
      $this->getBranchName());

    $map = array();

    $logs = explode("\1", trim($stdout));
    foreach (array_filter($logs) as $log) {
      list($node, $desc) = explode("\2", $log);
      $map[$node] = $desc;
    }

    return array_reverse($map);
  }

  public function loadWorkingCopyDifferentialRevisions(
    ConduitClient $conduit,
    array $query) {

    $messages = $this->getCommitMessageLog();
    $parser = new ArcanistDiffParser();

    // First, try to find revisions by explicit revision IDs in commit messages.
    $reason_map = array();
    $revision_ids = array();
    foreach ($messages as $node_id => $message) {
      $object = ArcanistDifferentialCommitMessage::newFromRawCorpus($message);

      if ($object->getRevisionID()) {
        $revision_ids[] = $object->getRevisionID();
        $reason_map[$object->getRevisionID()] = $node_id;
      }
    }

    if ($revision_ids) {
      $results = $conduit->callMethodSynchronous(
        'differential.query',
        $query + array(
          'ids' => $revision_ids,
        ));

      foreach ($results as $key => $result) {
        $hash = substr($reason_map[$result['id']], 0, 16);
        $results[$key]['why'] =
          "Commit message for '{$hash}' has explicit 'Differential Revision'.";
      }

      return $results;
    }

    // Try to find revisions by hash.
    $hashes = array();
    foreach ($this->getLocalCommitInformation() as $commit) {
      $hashes[] = array('hgcm', $commit['commit']);
    }

    if ($hashes) {

      // NOTE: In the case of "arc diff . --uncommitted" in a Mercurial working
      // copy with dirty changes, there may be no local commits.

      $results = $conduit->callMethodSynchronous(
        'differential.query',
        $query + array(
          'commitHashes' => $hashes,
        ));

      foreach ($results as $key => $hash) {
        $results[$key]['why'] =
          "A mercurial commit hash in the commit range is already attached ".
          "to the Differential revision.";
      }

      return $results;
    }

    return array();
  }

  public function updateWorkingCopy() {
    $this->execxLocal('up');
  }

  public function amendCommit($message) {
    $tmp_file = new TempFile();
    Filesystem::writeFile($tmp_file, $message);
    $this->execxLocal(
      'commit --amend -l %s',
      $tmp_file);
  }

  public function setIncludeDirectoryStateInDiffs($include) {
    $this->includeDirectoryStateInDiffs = $include;
    return $this;
  }

  public function getCommitSummary($commit) {
    if ($commit == 'null') {
      return '(The Empty Void)';
    }

    list($summary) = $this->execxLocal(
      'log --template {desc} --limit 1 --rev %s',
      $commit);

    $summary = head(explode("\n", $summary));

    return trim($summary);
  }

  public function resolveBaseCommitRule($rule, $source) {
    list($type, $name) = explode(':', $rule, 2);

    switch ($type) {
      case 'hg':
        $matches = null;
        if (preg_match('/^gca\((.+)\)$/', $name, $matches)) {
          list($err, $merge_base) = $this->execManualLocal(
            'log --template={node} --rev %s',
            sprintf('ancestor(., %s)', $matches[1]));
          if (!$err) {
            $this->setBaseCommitExplanation(
              "it is the greatest common ancestor of '{$matches[1]}' and ., as".
              "specified by '{$rule}' in your {$source} 'base' ".
              "configuration.");
            return trim($merge_base);
          }
        } else {
          list($err) = $this->execManualLocal(
            'id -r %s',
            $name);
          if (!$err) {
            $this->setBaseCommitExplanation(
              "it is specified by '{$rule}' in your {$source} 'base' ".
              "configuration.");
            return $name;
          }
        }
        break;
      case 'arc':
        switch ($name) {
          case 'empty':
            $this->setBaseCommitExplanation(
              "you specified '{$rule}' in your {$source} 'base' ".
              "configuration.");
            return 'null';
          case 'outgoing':
            list($err, $outgoing_base) = $this->execManualLocal(
              'log --template={node} --rev %s',
              'limit(reverse(ancestors(.) - outgoing()), 1)'
            );
            if (!$err) {
              $this->setBaseCommitExplanation(
                "it is the first ancestor of the working copy that is not ".
                "outgoing, and it matched the rule {$rule} in your {$source} ".
                "'base' configuration.");
              return trim($outgoing_base);
            }
          case 'amended':
            $text = $this->getCommitMessage('.');
            $message = ArcanistDifferentialCommitMessage::newFromRawCorpus(
              $text);
            if ($message->getRevisionID()) {
              $this->setBaseCommitExplanation(
                "'.' has been amended with 'Differential Revision:', ".
                "as specified by '{$rule}' in your {$source} 'base' ".
                "configuration.");
              // NOTE: This should be safe because Mercurial doesn't support
              // amend until 2.2.
              return '.^';
            }
            break;
          case 'bookmark':
            $revset =
              'limit('.
              '  sort('.
              '    (ancestors(.) and bookmark() - .) or'.
              '    (ancestors(.) - outgoing()), '.
              '  -rev),'.
              '1)';
            list($err, $bookmark_base) = $this->execManualLocal(
              'log --template={node} --rev %s',
              $revset);
            if (!$err) {
              $this->setBaseCommitExplanation(
                "it is the first ancestor of . that either has a bookmark, or ".
                "is already in the remote and it matched the rule {$rule} in ".
                "your {$source} 'base' configuration");
              return trim($bookmark_base);
            }
        }
        break;
      default:
        return null;
    }

    return null;

  }

  public function getSubversionInfo() {
    $info = array();
    $base_path = null;
    $revision = null;
    list($err, $raw_info) = $this->execManualLocal('svn info');
    if (!$err) {
      foreach (explode("\n", trim($raw_info)) as $line) {
        list($key, $value) = explode(': ', $line, 2);
        switch ($key) {
          case 'URL':
            $info['base_path'] = $value;
            $base_path = $value;
            break;
          case 'Repository UUID':
            $info['uuid'] = $value;
            break;
          case 'Revision':
            $revision = $value;
            break;
          default:
            break;
        }
      }
      if ($base_path && $revision) {
        $info['base_revision'] = $base_path.'@'.$revision;
      }
    }
    return $info;
  }

  public function getActiveBookmark() {
    list($raw_output) = $this->execxLocal('bookmarks');
    $raw_output = trim($raw_output);
    if ($raw_output !== 'no bookmarks set') {
      foreach (explode("\n", $raw_output) as $line) {
        $line = trim($line);
        if ('*' === $line[0]) {
          return idx(explode(' ', $line, 3), 1);
        }
      }
    }
    return null;
  }

}