<?php

require_once 'MTrack/Repo.php';

abstract class MTrackSCM
{

  // statics...
    static $repos = array();


    static function makeBreadcrumbs($pi) {
        if (!strlen($pi)) {
          $pi = '/';
        }
        if ($pi == '/') {
          $crumbs = array('');
        } else {
          $crumbs = explode('/', $pi);
        }
        return $crumbs;
    }

    static function makeDisplayName($data) {
        $parent = '';
        $name = '';
        if (is_object($data)) {
          $parent = $data->parent;
          $name = $data->shortname;
        } else if (is_array($data)) {
          $parent = $data['parent'];
          $name = $data['shortname'];
        }
        if ($parent) {
          list($type, $owner) = explode(':', $parent);
          return "$owner/$name";
        }
        return "default/$name";
    }

    /**
     * was run tool...
     */

    static function run($toolname, $mode, $args = null)
    {
        global $FORKS; //??? why?
        
        static $tools; // we cache the lookups...
                //- we could use the config for this... (as per original..)
                // but that would only be needed or realy heavily loaded sites.
                
        
        require_once 'System.php';
        $tool = isset($tools[$toolname]) ? $tools[$toolname] :  System::which($toolname);
        $tools[$toolname] = $tool;
        
        
        if (empty($tool)) {
            throw new Exception("Could not find '$toolname'");
        }
         
        $cmd = $tool;
        $args = is_array($args) ? $args : array();
        
        foreach ($args as $arg) {
            if (!is_array($arg)) {
                $cmd .= ' ' . MTrackSCM::escapeshellarg($arg);
                continue;
            }
            
            foreach ($arg as $a) {
                $cmd .= ' ' . MTrackSCM::escapeshellarg($a);
            }
        }
        
        if (!isset($FORKS[$cmd])) {
            $FORKS[$cmd] = 0;
        }
        $FORKS[$cmd]++;
        //echo  $cmd;
        // debugging....
        if (false) {
            if (php_sapi_name() == 'cli') {
                echo $cmd, "\n";
            } else {
                error_log($cmd);
                echo htmlentities($cmd) . "<br>\n";
            }
        }

        switch ($mode) {
            case 'read':   return popen($cmd, 'r');
            case 'write':  return popen($cmd, 'w');
            case 'string': return stream_get_contents(popen($cmd, 'r'));
            case 'proc':
              $pipedef = array(
                0 => array('pipe', 'r'),
                1 => array('pipe', 'w'),
                2 => array('pipe', 'w'),
              );
              $proc = proc_open($cmd, $pipedef, $pipes);
              return array($proc, $pipes);
        }
    }
    
    static function escapeshellarg($a) {
        if (preg_match('/\-[a-z0-9]+$/i', $a)) {
            return $a; // raw -a
        }
        if (preg_match('/\-\-[a-z0-9]+=/i', $a)) {
            $lr = explode('=', $a,2);
            return $lr[0].'=' . escapeshellarg($lr[1]); // raw -a
        }
        return escapeshellarg($a);
        
        
    }
    
    public $repopath = '';
    /*
    static function factory(&$repopath) {
        // [ / owner type rest ] 
        $bits = explode('/', $repopath, 4);
        //  print_r($bits);
        if (count($bits) < 3) {
          throw new Exception("Invalid repo $repopath");
        }
        array_shift($bits);
        list($owner, $type) = $bits;
        $repo = "$owner/$type";
        
        $r = MTrack_Repo::loadByName($repo);
        if (!$r) {
          throw new Exception("invalid repo $repo");
        }
        $repopath = isset($bits[2]) ? $bits[2] : '';
        $r->repopath = $repopath;
        return $r;
    }
    */
    
    /** Returns an array keyed by possible branch names.
    * The data associated with the branches is implementation
    * defined.
    * If the SCM does not have a concept of first-class branch
    * objects, this function returns null */
    abstract public function getBranches();
    
    /** Returns an array keyed by possible tag names.
    * The data associated with the tags is implementation
    * defined.
    * If the SCM does not have a concept of first-class tag
    * objects, this function returns null */
    abstract public function getTags();
    
    /** Enumerates the files/dirs that are present in the specified
    * location of the repository that match the specified revision,
    * branch or tag information.  If no revision, branch or tag is
    * specified, then the appropriate default is assumed.
    *
    * The second and third parameters are optional; the second
    * parameter is one of 'rev', 'branch', or 'tag', and if specifed
    * the third parameter must be the corresponding revision, branch
    * or tag identifier.
    *
    * The return value is an array of MTrackSCMFile objects present
    * at that location/revision of the repository.
    */
    abstract public function readdir($path, $object = null, $ident = null);
    
    /** Queries information on a specific file in the repository.
    *
    * Parameters are as for readdir() above.
    *
    * This function returns a single MTrackSCMFile for the location
    * in question.
    */
    abstract public function file($path, $object = null, $ident = null);
    
    /** Queries history for a particular location in the repo.
    *
    * Parameters are as for readdir() above, except that path can be
    * left unspecified to query the history for the entire repo.
    *
    * The limit parameter limits the number of entries returned; it it is
    * a number, it specifies the number of events, otherwise it is assumed
    * to be a date in the past; only events since that date will be returned.
    *
    * Returns an array of MTrackSCMEvent objects.
    */
    abstract public function history($path, $limit = null, $object = null,
    $ident = null);
    
    /** Obtain the diff text representing a change to a file.
    *
    * You may optionally provide one or two revisions as context.
    *
    * If no revisions are passed in, then the change associated
    * with the location will be assumed.
    *
    * If one revision is passed, then the change associated with
    * that event will be assumed.
    *
    * If two revisions are passed, then the difference between
    * the two events will be assumed.
    */
    abstract public function diff($path, $from = null, $to = null);
    
    /** Determine the next and previous revisions for a given
    * changeset.
    *
    * Returns an array: the 0th element is an array of prior revisions,
    * and the 1st element is an array of successor revisions.
    *
    * There will usually be one prior and one successor revision for a
    * given change, but some SCMs will return multiples in the case of
    * merges.
    */
    abstract public function getRelatedChanges($revision);
    
    /** Returns a working copy object for the repo
    *
    * The intended purpose is to support wiki page modifications, and
    * as such, is not meant to be an especially efficient means to do so.
    */
    abstract public function getWorkingCopy();
    
    /** Returns meta information about the SCM type; this is used in the
    * UI and tooling to let the user know their options.
    *
    * Returns an array with the following keys:
    * 'name' => 'Mercurial', // human displayable name
    * 'tools' => array('hg'), // list of tools to find during setup
    */
    abstract public function getSCMMetaData();
    
    /** Returns the default 'root' location in the repository.
    * For SCMs that have a concept of branches, this is the empty string.
    * For SCMs like SVN, this is the trunk dir */
    public function getDefaultRoot() {
    return '';
    }

  
  /* takes an MTrackSCM as a parameter because in some bootstrapping
   * cases, we're actually MTrack_Repo and not the end-class.
   * MTrack_Repo calls the end-class method and passes itself in for
   * context */
  public function reconcileRepoSettings(MTrackSCM $r) {
    throw new Exception(
      "Creating/updating a repo of type $this->scmtype is not implemented");
  }


  public function getBrowseRootName() {
    return self::makeDisplayName($this);
  }

    public function resolveRevision($rev, $object, $ident)
    {
        if ($rev !== null) {
            return $rev;
        }
        
        if ($object === null) {
            return null;
        }
        
        switch ($object) {
            case 'rev':
                $rev = $ident;
                break;
            
            case 'branch':
                $branches = $this->getBranches();
                $rev = isset($branches[$ident]) ? $branches[$ident] : null;
                break;
            
            case 'tag':
              $tags = $this->getTags();
              $rev = isset($tags[$ident]) ? $tags[$ident] : null;
              break;
        }
        if ($rev === null) {
          throw new Exception(
            "don't know which revision to use ($rev,$object,$ident)");
        }
      return $rev;
    }

     
}