<?php
// $Id$
/**
 * @file
 * Git backend for Version Control API - Provides Git commit information and
 * account management as a pluggable backend.
 *
 * Copyright 2008 by Jimmy Berry ("boombatower", http://drupal.org/user/214218)
 */

// Update methods.
define('VERSIONCONTROL_GIT_UPDATE_CRON', 0);

// The admin and user edit pages.
include_once(drupal_get_path('module', 'versioncontrol_git') .'/versioncontrol_git.admin.inc');

/**
 * Implementation of hook_versioncontrol_backends().
 *
 * @return
 *   A structured array containing information about this known backends.
 *   Array key is the unique string identifier of the version control system.
 *   The corresponding array values are again structured arrays and consist
 *   of elements with the following keys:
 *
 *   'name': The user-visible name of the VCS.
 *   'description': A short description of the backend, if possible not longer
 *                  than one or two sentences.
 *   'capabilities': An array listing optional capabilities, in addition to the
 *                   required functionality like retrieval of detailed
 *                   commit information. Array values can be an arbitrary
 *                   combination of VERSIONCONTROL_CAPABILITY_* values. If no
 *                   additional capabilities are supported by the backend,
 *                   this array will be empty.
 *   'autoadd': An array listing which tables should be managed by
 *              Version Control API instead of doing it manually in
 *              the backend. Array values can be an arbitrary combination of
 *              VERSIONCONTROL_AUTOADD_* values. If no array additions
 *              should be automatically managed, this array will be empty.
 */
function versioncontrol_git_versioncontrol_backends() {
  return array(
    // The array key is up to 8 characters long, and used as unique identifier
    // for this VCS, in functions, URLs and in the database.
    'git' => array(
      // The user-visible name of the VCS.
      'name' => 'GIT',

      // A short description of the VCS, if possible not longer than one or two sentences.
      'description' => t('GIT (GNU Interactive Tools) is a fast directory content manager, originally written for use with large repositories, such as the Linux Kernel source.'),

      // A list of optional capabilities, in addition to the required retrieval
      // of detailed commit information.
      'capabilities' => array(
        // Able to cancel commits if the committer lacks permissions
        // to commit to specific paths and/or branches.
        VERSIONCONTROL_CAPABILITY_COMMIT_RESTRICTIONS,
        // Able to cancel branch or tag assignments if the committer lacks
        // permissions to create/update/delete those.
        VERSIONCONTROL_CAPABILITY_BRANCH_TAG_RESTRICTIONS,
      ),

      // An array listing which tables should be managed by Version Control API
      // instead of doing it manually in the backend.
      'flags' => array(
        // versioncontrol_insert_repository() will automatically insert
        // array elements from $repository['git_specific'] into
        // {versioncontrol_git_repositories} and versioncontrol_get_repositories()
        // will automatically fetch it from there.
        VERSIONCONTROL_FLAG_AUTOADD_REPOSITORIES,
        // versioncontrol_insert_commit() will automatically insert
        // array elements from $commit['git_specific'] into
        // {versioncontrol_git_commits} and versioncontrol_get_commits()
        // will automatically fetch it from there.
        VERSIONCONTROL_FLAG_AUTOADD_COMMITS,
      ),
    ),
  );
}

/**
 * Implementation of hook_menu().
 */
function versioncontrol_git_menu($may_cache) {
  global $user;
  $items = array();
  $admin_access = user_access('administer version control systems');

  if ($may_cache) {
    $items[] = array(
      'path' => 'admin/project/versioncontrol-repositories/update/git',
      'title' => t('Fetch log'),
      'callback' => 'versioncontrol_git_update_repository_callback',
      'access' => $admin_access,
      'type' => MENU_CALLBACK,
    );
  }
  return $items;
}

/**
 * Implementation of hook_cron():
 * Update repositories that have log fetching enabled.
 */
function versioncontrol_git_cron() {
  $result = db_query("SELECT repo_id FROM {versioncontrol_git_repositories}
                      WHERE update_method = %d", VERSIONCONTROL_GIT_UPDATE_CRON);

  // Set timeout limit to 3600 seconds as it can take a long time to process
  // the log initially. (And hook_cron() might be called by poormanscron.)
  if (!ini_get('safe_mode')) {
    set_time_limit(3600);
  }
  while ($repo = db_fetch_object($result)) {
    $repository = versioncontrol_get_repository($repo->repo_id);
    if (isset($repository)) {
      _versioncontrol_git_update_repository($repository);
    }
  }
}

/**
 * Implementation of [versioncontrol_backend]_get_commit_actions():
 * Retrieve detailed information about what happened in a single commit.
 *
 * @param $commit
 *   The commit whose actions should be retrieved.
 *
 * @return
 *   A structured array containing the exact details of what happened to
 *   each item in this commit. Array keys are the current/new paths, also for
 *   VERSIONCONTROL_ACTION_DELETED actions even if the file actually doesn't
 *   exist anymore. The corresponding array values are again structured arrays
 *   and consist of elements with the following keys:
 *
 *   'action': Specifies how the item was modified.
 *             One of the predefined VERSIONCONTROL_ACTION_* values.
 *   'modified': Boolean value, specifies if a file was modified in addition
 *               to the other action in the 'action' element of the array.
 *               Only exists for the VERSIONCONTROL_ACTION_MOVED
 *               and VERSIONCONTROL_ACTION_COPIED actions.
 *   'current item': The updated state of the modified item. Exists for all
 *                   actions except VERSIONCONTROL_ACTION_DELETED.
 *   'source items': An array with the previous state(s) of the modified item.
 *                   Path and branch will always be the same as in the current
 *                   item except for the VERSIONCONTROL_ACTION_MOVED,
 *                   VERSIONCONTROL_ACTION_COPIED and
 *                   VERSIONCONTROL_ACTION_MERGED actions.
 *                   Exists for all actions except VERSIONCONTROL_ACTION_ADDED.
 *
 *   Item values are structured arrays and consist of elements
 *   with the following keys:
 *
 *   'type': Specifies the item type, which is either
 *           VERSIONCONTROL_ITEM_FILE or VERSIONCONTROL_ITEM_DIRECTORY.
 *   'path': The path of the item at the specific revision.
 *   'revision': The (file-level) revision when the item was changed.
 *               If there is no such revision (which may be the case for
 *               directory items) then the 'revision' element is
 *               an empty string.
 *   '[xxx]_specific': May be set by the backend to remember additional
 *                     item info. ("[xxx]" is the unique string identifier
 *                     of the respective version control system.)
 */
function versioncontrol_git_get_commit_actions($commit) {
  include_once(drupal_get_path('module', 'versioncontrol_git') .'/versioncontrol_git.log.inc');

  $actions = array();
  $result = db_query('SELECT item_revision_id, action, type, path,
                             commit_id, lines_added, lines_removed
                      FROM {versioncontrol_git_item_revisions}
                      WHERE vc_op_id = %d', $commit['vc_op_id']);

  while ($item_revision = db_fetch_object($result)) {
    $action = array(
      'action' => $item_revision->action,
      'git_specific' => array(
        'lines_added' => $item_revision->lines_added,
        'lines_removed' => $item_revision->lines_removed,
      ),
    );

    if ($item_revision->action != VERSIONCONTROL_ACTION_DELETED) {
      $action['current item'] = array(
        'type' => $item_revision->type,
        'path' => $item_revision->path,
        'revision' => $item_revision->commit_id,
        'git_specific' => array(
          'item_revision_id' => $item_revision->item_revision_id,
          'selected_branch_id' => $commit['git_specific']['branch_id'],
          'selected_op' => $commit,
        ),
      );
    }
    if ($item_revision->action != VERSIONCONTROL_ACTION_ADDED) {
      $source_revision = versioncontrol_git_get_previous_commit_id($commit['repository']['repo_id'], $item_revision->path, $commit['vc_op_id']);
      $action['source items'] = array(array(
        'type' => $item_revision->type,
        'path' => $item_revision->path,
        'revision' => isset($source_revision) ? $source_revision : '',
        'git_specific' => array(
          'item_revision_id' => $item_revision->item_revision_id,
          'selected_branch_id' => $commit['git_specific']['branch_id'],
          'selected_op' => $commit,
        ),
      ));
    }

    $actions[$item_revision->path] = $action;
  }

  return $actions;
}

/**
 * Implementation of [versioncontrol_backend]_get_commit_statistics():
 * Retrieve general statistics about what happened in a single commit. For more granular
 * details about what happened in a single commit, use versioncontrol_get_commit_actions.
 *
 * @param $commit
 *   The commit to retrieve statistics about
 *
 * @return
 *  A structured array containing general statistics about this commit. The array will consist
 *  of elements with the following keys:
 *
 *   - 'lines_added': Total number of lines added during this commit
 *   - 'lines_removed': Total number of lines removed during this commit
 *   - 'action_count': Total number of actions within this commit
 *   - 'per_action_statistics': An array containing statistics on individual actions. Array keys are
 *        the current/new paths (just as with versioncontrol_get_commit_actions). The corresponding
 *        array values are again structured arrays and consist of elements with the following keys:
 *   
 *   - 'lines_added': Number of lines added in this action
 *   - 'lines_removed': Number of lines removed in this action
 */
function versioncontrol_git_get_commit_statistics($commit, $commit_actions = NULL) {
  if ($commit_actions == NULL) {
    $commit_actions = versioncontrol_git_get_commit_actions($commit);
  }

  $total_lines_added = 0;
  $total_lines_removed = 0;
  $per_action = array();

  foreach ($commit_actions as $path => $action) {
    $per_action[$path] = array();

    $per_action[$path]['lines_added'] = $action['git_specific']['lines_added'];
    $total_lines_added += $per_action[$path]['lines_added'];

    $per_action[$path]['lines_removed'] = $action['git_specific']['lines_removed'];
    $total_lines_removed += $action['git_specific']['lines_removed'];
  }

  return array(
    'lines_added' => $total_lines_added,
    'lines_removed' => $total_lines_removed,
    'action_count' => count($per_action),
    'per_action_statistics' => $per_action,
  );
}

/**
 * Implementation of [versioncontrol_backend]_get_directory_item():
 * Retrieve the item of the deepest-level directory in the repository that is
 * common to all the changed/branched/tagged items in a commit, branch or
 * tag operation. In other words, this function gets you the item
 * for $operation['directory'].
 *
 * @param $operation
 *   The commit, branch or tag operation whose deepest-level
 *   changed/branched/tagged directory should be retrieved.
 *
 * @return
 *   The requested directory item. Item values are structured arrays and
 *   consist of elements with the following keys:
 *
 *   - 'type': Specifies the item type, which in this case can only be
 *        VERSIONCONTROL_ITEM_DIRECTORY.
 *   - 'path': The path of the directory, which will be the same
 *        as $operation['directory'].
 *   - 'revision': The (file-level) revision when the item was last changed.
 *        If there is no such revision (which may be the case for
 *        directory items) then the 'revision' element is an empty string.
 *   - '[xxx]_specific': May be set by the backend to remember additional
 *        item info. ("[xxx]" is the unique string identifier
 *        of the respective version control system.)
 */
function versioncontrol_git_get_directory_item($operation) {
  $item = array(
    'type' => VERSIONCONTROL_ITEM_DIRECTORY,
    'path' => $operation['directory'],
    'commit_id' => '',
    'git_specific' => array(
      'selected_op' => $operation,
    ),
  );
  if (isset($operation['git_specific']['branch_id'])) { // It's a commit or branch.
    $item['git_specific']['selected_branch_id'] = $operation['git_specific']['branch_id'];
  }
  return $item;
}

/**
 * Implementation of [versioncontrol_backend]_get_commit_branches():
 * Retrieve the branches that have been affected by the given commit.
 *
 * @return
 *   An array of strings that identify a branch in the respective repository,
 *   or an empty array if no branches were affected at all. (For GIT, there
 *   should always be a exactly one branch in the resulting array.)
 */
function versioncontrol_git_get_commit_branches($commit) {
  if (!isset($commit['git_specific']['branch_id'])) {
    return array();
  }

  $branch = versioncontrol_get_branch($commit['git_specific']['branch_id']);
  if (!isset($branch)) {
    return array(); // should only happen in case of database inconsistencies
  }
  return array($branch['branch_name']);
}

/**
 * Retrieve the set of items that were affected by a branch operation.
 *
 * @param $branch
 *   The branch operation whose items should be retrieved. This is an array
 *   like the one returned by versioncontrol_get_branch_operation().
 *
 * @return
 *   An array of all items that were affected by the branching operation.
 *   An empty result array means that the whole repository has been branched.
 *   Item values are structured arrays and consist of elements
 *   with the following keys:
 *
 *   - 'type': Specifies the item type, which is either
 *        VERSIONCONTROL_ITEM_FILE or VERSIONCONTROL_ITEM_DIRECTORY.
 *   - 'path': The path of the item at the specific revision.
 *   - 'revision': The (file-level) revision when the item was changed.
 *        If there is no such revision (which may be the case for
 *        directory items) then the 'revision' element is an empty string.
 *   - 'source branch': Optional, may be set by the backend if the
 *        source branch (the one that this one branched off) can be retrieved.
 *        If given, this is a string with the original branch name.
 *   - '[xxx]_specific': May be set by the backend to remember additional
 *        item info. ("[xxx]" is the unique string identifier of the respective
 *        version control system.)
 */
function versioncontrol_git_get_branched_items($branch) {
  $items = array();
  $result = db_query('SELECT ir.item_revision_id, ir.type, ir.path, ir.revision
                      FROM {versioncontrol_git_item_branch_points} ib
                       INNER JOIN {versioncontrol_git_item_revisions} ir
                        ON ib.item_revision_id = ir.item_revision_id
                      WHERE ib.vc_op_id = %d', $branch['vc_op_id']);

  while ($item_revision = db_fetch_object($result)) {
    $items[] = array(
      'type' => $item_revision->type,
      'path' => $item_revision->path,
      'revision' => $item_revision->revision,
      'git_specific' => array(
        'item_revision_id' => $item_revision->item_revision_id,
        'selected_branch_id' => $branch['git_specific']['branch_id'],
        'selected_op' => $branch,
      ),
    );
  }
  return $items;
}

/**
 * Retrieve the set of items that were affected by a tag operation.
 *
 * @param $tag
 *   The tag operation whose items should be retrieved. This is an array
 *   like the one returned by versioncontrol_get_tag_operation().
 *
 * @return
 *   An array of all items that were affected by the tagging operation.
 *   An empty result array means that the whole repository has been tagged.
 *   Item values are structured arrays and consist of elements
 *   with the following keys:
 *
 *   - 'type': Specifies the item type, which is either
 *        VERSIONCONTROL_ITEM_FILE or VERSIONCONTROL_ITEM_DIRECTORY.
 *   - 'path': The path of the item at the specific revision.
 *   - 'revision': The (file-level) revision when the item was changed.
 *        If there is no such revision (which may be the case for
 *        directory items) then the 'revision' element is an empty string.
 *   - 'source branch': Optional, may be set by the backend if the
 *        source branch (the one that this tag comes from) can be retrieved.
 *        If given, this is a string with the original branch name.
 *   - '[xxx]_specific': May be set by the backend to remember additional
 *        item info. ("[xxx]" is the unique string identifier of the respective
 *        version control system.)
 */
function versioncontrol_git_get_tagged_items($tag) {
  $items = array();
  $result = db_query('SELECT ir.item_revision_id, ir.type, ir.path, ir.revision
                      FROM {versioncontrol_git_item_tags} it
                       INNER JOIN {versioncontrol_git_item_revisions} ir
                        ON it.item_revision_id = ir.item_revision_id
                      WHERE it.vc_op_id = %d', $tag['vc_op_id']);

  while ($item_revision = db_fetch_object($result)) {
    $items[] = array(
      'type' => $item_revision->type,
      'path' => $item_revision->path,
      'revision' => $item_revision->revision,
      'git_specific' => array(
        'item_revision_id' => $item_revision->item_revision_id,
        'selected_op' => $tag,
      ),
    );
  }
  return $items;
}

/**
 * Implementation of [versioncontrol_backend]_get_current_item_branch():
 * Retrieve the current branch that this item is in. If this item was part of
 * the result of versioncontrol_get_commit_actions(), this will probably be
 * the branch that this item was committed to. The main branch ('HEAD' for GIT)
 * is also a valid branch and should be expected as return value.
 *
 * @param $repository
 *   The repository that the item is located in.
 * @param $item
 *   The item whose current branch should be retrieved.
 *
 * @return
 *   A string containing the current item branch, or NULL if no branch
 *   is known or applicable.
 */
function versioncontrol_git_get_current_item_branch($repository, $item) {
  if (!isset($item['git_specific']['selected_branch_id'])) {
    return NULL;
  }

  $branch = versioncontrol_get_branch($item['git_specific']['selected_branch_id']);
  if (!isset($branch)) {
    return NULL;
  }
  return $branch['branch_name'];
}

/**
 * Implementation of [versioncontrol_backend]_get_current_item_tag():
 * Retrieve the current tag of this item.
 *
 * @param $repository
 *   The repository that the item is located in.
 * @param $item
 *   The item whose current branch should be retrieved.
 *
 * @return
 *   A tag operation array like the return value
 *   of versioncontrol_get_tag_operation(), or NULL if no tag
 *   is known or applicable.
 */
function versioncontrol_git_get_current_item_tag($repository, $item) {
  if ($item['git_specific']['selected_op']['type'] != VERSIONCONTROL_OPERATION_TAG) {
    return NULL;
  }
  return $item['git_specific']['selected_op'];
}

/**
 * Implementation of [vcs_backend]_get_parent_item():
 * Retrieve the parent (directory) item of a given item.
 *
 * @param $repository
 *   The repository that the item is located in.
 * @param $item
 *   The item whose parent should be retrieved.
 * @param $parent_path
 *   NULL if the direct parent of the given item should be retrieved,
 *   or a parent path that is further up the directory tree.
 *
 * @return
 *   The parent directory item at the same revision as the given item.
 *   If $parent_path is not set and the item is already the topmost one
 *   in the repository, the item is returned as is. It also stays the same
 *   if $parent_path is given and the same as the path of the given item.
 *   If the given directory path does not correspond to a parent item,
 *   NULL is returned.
 */
function versioncontrol_git_get_parent_item($repository, $item, $parent_path = NULL) {
  if (!isset($parent_path)) {
    $item['path'] = dirname($item['path']);
    return $item;
  }
  else if (strpos($item['path'] .'/', $parent_path .'/') !== FALSE) {
    $item['path'] = $parent_path;
    return $item;
  }
  return NULL;
}

/**
 * Menu callback for 'admin/project/versioncontrol-repositories/update/git'
 * (expecting a $repo_id as one more path argument):
 * Retrieve/validate the specified repository, fetch new commits, tags
 * and branches by invoking the git executable, output messages and
 * redirect back to the repository page.
 */
function versioncontrol_git_update_repository_callback($repo_id) {
  if (is_numeric($repo_id)) {
    $repository = versioncontrol_get_repository($repo_id);

    if (isset($repository)) {
      $update_method = $repository['git_specific']['update_method'];
    }
  }
  if (isset($update_method) && $update_method == VERSIONCONTROL_GIT_UPDATE_CRON) {
    // Set timeout limit to 3600 seconds as it can take a long time
    // to process the log initially.
    if (!ini_get('safe_mode')) {
      set_time_limit(3600);
    }
    if (_versioncontrol_git_update_repository($repository)) {
      drupal_set_message(t('Fetched new log entries.'));
    }
  }
  else { // $repo_id is not a number or doesn't correlate to any repository.
    drupal_set_message(t('No such repository, did not fetch anything.'));
  }
  drupal_goto('admin/project/versioncontrol-repositories');
}

/**
 * Actually update the repository by fetching commits and other stuff
 * directly from the repository, invoking the git executable.
 *
 * @return
 *   TRUE if the logs were updated, or FALSE if fetching and updating the logs
 *   failed for whatever reason.
 */
function _versioncontrol_git_update_repository(&$repository) {
  include_once(drupal_get_path('module', 'versioncontrol_git') .'/versioncontrol_git.log.inc');
  return _versioncontrol_git_log_update_repository($repository);
}

/**
 * Implementation of [versioncontrol_backend]_commit():
 * Manage (insert or delete) additional commit data in the database.
 *
 * @param $op
 *   Either 'insert' when the commit is in the process of being created,
 *   or 'delete' if it will be deleted after this function has been called.
 * @param $commit
 *   A single commit array, like the ones returned
 *   by versioncontrol_get_commits().
 * @param $commit_actions
 *   A structured array containing the exact details of what happened to
 *   each item in this commit. The structure of this array is the same as
 *   the return value of versioncontrol_get_commit_actions().
 */
function versioncontrol_git_commit($op, $commit, $commit_actions) {
  switch ($op) {
    case 'insert':
      foreach ($commit_actions as $path => $action) {
        $commit_id = '';

        // If available, get item type and revision from the contained items.
        if (isset($action['current item'])) {
          $type = $action['current item']['type'];
          $commit_id = $action['current item']['commit_id'];
        }
        else { // no current item -> file has been deleted
          $type = VERSIONCONTROL_ITEM_FILE_DELETED;
          $commit_id = $action['git_specific']['commit_id'];
        }

        $item_revision_id = db_next_id('{versioncontrol_git_item_revisions}_item_revision_id');
        db_query(
          "INSERT INTO {versioncontrol_git_item_revisions}
           (item_revision_id, vc_op_id, type, path, commit_id,
            action, lines_added, lines_removed)
           VALUES (%d, %d, %d, '%s', '%s', %d, %d, %d)",
          $item_revision_id, $commit['vc_op_id'], $type, $path, $commit_id,
          $action['action'], $action['git_specific']['lines_added'],
          $action['git_specific']['lines_removed']
        );
      }
      break;

    case 'delete':
      $result = db_query('SELECT item_revision_id
                          FROM {versioncontrol_git_item_revisions}
                          WHERE vc_op_id = %d', $commit['vc_op_id']);

      while ($revision = db_fetch_object($result)) {
        db_query('DELETE FROM {versioncontrol_git_item_tags}
                  WHERE item_revision_id = %d',
                  $revision->item_revision_id);
        db_query('DELETE FROM {versioncontrol_git_item_branch_points}
                  WHERE item_revision_id = %d',
                  $revision->item_revision_id);
      }
      db_query('DELETE FROM {versioncontrol_git_item_revisions}
                WHERE vc_op_id = %d', $commit['vc_op_id']);
      break;
  }
}