<?php
interface h5pFramework {
  public function setErrorMessage($message);
  public function setInfoMessage($message);
  public function t($message, $replacements);
  public function getUploadedH5pDir();
  public function getTempPath();
  public function getUploadedH5pPath();
  public function isStoredLibrary($machineName, $minimumVersion);
}

class h5pValidator {
  public $h5pF;
  public $h5pC;
  
  // Schemas used to validate the h5p files
  private $h5pRequired = array(
    'title' => '/^.{1,255}$/',
    'mainVersion' => '/^[0-9]{1,5}$/',
    'language' => '/^[a-z]{1,5}$/',
    'machineName' => '/^[a-z0-9\-]{1,255}$/',
    'preloadedDependencies' => array(
      'machineName' => '/^[a-z0-9\-]{1,255}$/',
      'minimumVersion' => '/^[0-9]{1,5}$/',
    ),
    'init' => '/^[$a-z_][0-9a-z_\.$]{1,254}$/i',
    'embedTypes' => array('iframe', 'div'),
  );
  
  private $h5pOptional = array(
    'contentType' => '/^.{1,255}$/',
    'utilization' => '/^.{1,}$/',
    'subVersion' => '/^[0-9]{1,5}$/',
    'author' => '/^.{1,255}$/',
    'lisence' => '/^(iframe|div)$/',
    'dynamicDependencies' => array(
      'machineName' => '/^[a-z0-9\-]{1,255}$/',
      'minimumVersion' => '/^[0-9]{1,5}$/',
    ),
    'preloadedJs' => '/^(\\[a-z_\-\s0-9\.]+)+\.(?i)(js)$/',
    'preloadedCss' => '/^(\\[a-z_\-\s0-9\.]+)+\.(?i)(js)$/',
    'w' => '/^[0-9]{1,4}$/',
    'h' => '/^[0-9]{1,4}$/',
    'metaKeywords' => '/^.{1,}$/',
    'metaDescription' => '/^.{1,}$/k',
  );

  // These are the same as above, except the preloadedDependencies are optional. Created in the constructor.
  private $h5pLibraryRequired;
  private $h5pLibraryOptional;

  /**
   * Constructor for the h5pValidator
   *
   * @param object $h5pFramework
   *  The frameworks implementation of the h5pFramework interface
   */
  public function __construct($h5pFramework, $h5pCore) {
    $this->h5pF = $h5pFramework;
    $this->h5pC = $h5pCore;
    
    $this->h5pLibraryRequired = $this->arrayCopy($this->h5pLibraryRequired);
    $requiredDependencies = $this->h5pLibraryRequired['requiredDependencies'];
    unset($this->h5pLibraryRequired['requiredDependencies']);
    $this->h5pLibraryOptional = $this->arrayCopy($this->h5pLibraryRequired);
    $this->h5pLibraryOptional['requiredDependencies'] = $requiredDependencies;
  }

  /**
   * Validates a .h5p file
   *
   * @return boolean
   *  TRUE if the .h5p file is valid
   */
  public function validatePackage() {
    // Requires PEAR
    require_once 'Archive/Tar.php';

    // Create a temporary dir to extract package in.
    $tmp_dir = $this->h5pFramework->getUploadedH5pDir();
    $tmp_path = $this->h5pFramework->getUploadedH5pPath();

    $valid = TRUE;

    // Extract and then remove the package file.
    $tar = new Archive_Tar($tmp_path, 'bz2');
    if (!$tar->extract($tmp_dir)) {
      $this->h5pF->setErrorMessage($this->h5pF->t('The file you uploaded is not a valid HTML5 Pack.'));
      $this->delTree($tmp_dir);
      return;
    }
    unlink($tmp_path);

    // Process content and libraries
    $libraries = array();
    $files = scandir($tmp_dir);
    $mainH5pData;
    $mainH5pExists = $imageExists = $contentExists = FALSE;
    foreach ($files as $file) {
      if (in_array($file, array('.', '..'))) {
        continue;
      }
      $file_path = $tmp_dir . DIRECTORY_SEPARATOR . $file;
      if (strtolower($file) == 'h5p.json') {
        $mainH5pData = $this->getJsonData($file_path);
        if ($mainH5pData === FALSE) {
          $valid = FALSE;
          $this->h5pF->setErrorMessage($this->h5pF->t('Could not find or parse the main h5p.json file'));
        }
        else {
          $validH5p = $this->isValidH5pData($mainH5pData, $file, $this->h5pRequired, $this->h5pOptional);
          if ($validH5p) {
            $mainH5pExists = TRUE;
          }
          else {
            $valid = FALSE;
            $this->h5pF->setErrorMessage($this->h5pF->t('Could not find or parse the main h5p.json file'));
          }
        }
      }

      elseif (strtolower($file) == 'h5p.jpg') {
        $imageExists = TRUE;
      }
      elseif ($file == 'content') {
        $jsonData = $this->getJsonData($file_path . DIRECTORY_SEPARATOR . 'content.json');
        if ($jsonData === FALSE) {
          $this->h5pF->setErrorMessage($this->h5pF->t('Could not find or parse the content.json file'));
          $valid = FALSE;
          continue;
        }
        else {
          $contentExists = TRUE;
          // In the future we might let the librarys provide validation functions for content.json
        }
      }
      
      elseif (strpos($file, '.') !== FALSE) {
        // Illegal file fond. This is ignored.
        continue;
      }

      else {
        if (preg_match('/[^a-z0-9\-]/', $file) === 0) {
          $this->h5pF->setErrorMessage($this->h5pF->t('Invalid library name: %name', array('%name' => $file)));
          $valid = FALSE;
          continue;
        }
        $h5pData = $this->getJsonData($file_path . DIRECTORY_SEPARATOR . 'h5p.json');
        if ($h5pData === FALSE) {
          $this->h5pF->setErrorMessage($this->h5pF->t('Could not find h5p.json file with valid json format for library %name', array('%name' => $file)));
          $valid = FALSE;
          continue;
        }
        
        $validLibrary = $this->isValidH5pData($h5pData, $library_name, $this->h5pLibraryRequired, $this->h5pLibraryOptional);

        if (isset($h5pData->preloadedJs)) {
          $validLibrary = $this->isExcistingFiles($h5pData->preloadedJs, $tmp_dir, $file) && $validLibrary;
        }
        if (isset($h5pData->preloadedCss)) {
          $validLibrary = $this->isExcistingFiles($h5pData->preloadedCss, $tmp_dir, $file) && $validLibrary;
        }
        if ($validLibrary) {
          $libraries[$file][$h5pData['mainVersion']] = $h5pData;
        }
        $valid = $validLibrary && $valid;
      }
    }
    if (!$contentExists) {
      $this->h5pF->setErrorMessage($this->h5pF->t('A valid content folder is missing'));
      $valid = FALSE;
    }
    if (!$mainH5pExists) {
      $this->h5pF->setErrorMessage($this->h5pF->t('A valid main h5p.json file is missing'));
      $valid = FALSE;
    }
    if ($valid) {
      $libraries['mainH5pData'][] = $mainH5pData;
      $missingLibraries = $this->getMissingLibraries($libraries);
      foreach ($missingLibraries as $missing) {
        if ($this->h5pF->isStoredLibrary($missing['machineName'], $missing['minimumVersion'])) {
          unset($missingLibraries[$missing['machineName']]);
        }
      }
      $valid = empty($missingLibraries) && $valid;
    }
    if (!$valid) {
      $this->delTree($tmp_dir);
    }
    $this->h5pC->setParsedLibraries($libraries);
    return $valid;
  }

  /**
   * Use the dependency declarations to find any missing libraries
   *
   * @param array $libraries
   *  A multidimensional array of libraries keyed with machineName first and mainVersion second
   * @return array
   *  A list of libraries that are missing keyed with machineName and holds objects with
   *  machineName and minimumVersion properties
   */
  private function getMissingLibraries($libraries) {
    $missing = array();
    foreach ($libraries as $library) {
      $library = end($library);
      if (isset($library['preloadedDependencies'])) {
        array_merge($missing, $this->getMissingDependencies($library['preloadedDependencies'], $libraries));
      }
      if (isset($library['dynamicDependencies'])) {
        array_merge($missing, $this->getMissingDependencies($library['dynamicDependencies'], $libraries));
      }
    }
    return $missing;
  }

  /**
   * Helper function for getMissingLibraries, searches for dependency required libraries in
   * the provided list of libraries
   *
   * @param array $dependencies
   *  A list of objects with machineName and minimumVersion properties
   * @param array $libraries
   *  A multidimensional array of libraries keyed with machineName first and mainVersion second
   * @return
   *  A list of libraries that are missing keyed with machineName and holds objects with
   *  machineName and minimumVersion properties
   */
  private function getMissingDependencies($dependencies, $libraries) {
    $missing = array();
    foreach ($library['preloadedDependencies'] as $dependency) {
      if (isset($libraries[$dependency['machineName']])) {
        if ($libraries[$dependency['machineName']]['minimumVersion'] < $dependency['minimumVersion']) {
          $missing[$dependency['machineName']] = $dependency;
        }
      }
      else {
        $missing[$dependency['machineName']] = $dependency;
      }
    }
    return $missing;
  }

  /**
   * Figure out if the provided file paths exists
   *
   * Triggers error messages if files doesn't exist
   *
   * @param array $files
   *  List of file paths relative to $tmp_dir
   * @param string $tmp_dir
   *  Path to the directory where the $files are stored.
   * @param string $library
   *  Name of the library we are processing
   * @return boolean
   *  TRUE if all the files excists
   */
  private function isExcistingFiles($files, $tmp_dir, $library) {
    foreach ($files as $file_path) {
      $path = str_replace(array('/', '\\'), DIRECTORY_SEPARATOR, $file_path);
      if (!file_exists($tmp_dir . DIRECTORY_SEPARATOR . $path)) {
        $this->h5pF->setErrorMessage('The JS file %file is missing from library: %name', array('%file' => $file_path, '%name' => $library));
        return FALSE;
      }
    }
    return TRUE;
  }

  /**
   * Validates h5p.json data
   *
   * Error messages are triggered if the data isn't valid
   *
   * @param array $h5pData
   *  h5p data
   * @param string $library_name
   *  Name of the library we are processing
   * @param array $required
   *  Validation pattern for required properties
   * @param array $optional
   *  Validation pattern for optional properties
   * @return boolean
   *  TRUE if the $h5pData is valid
   */
  private function isValidH5pData($h5pData, $library_name, $required, $optional) {
    $valid = $this->isValidRequiredH5pData($h5pData, $required, $library_name);
    $valid = $this->isValidOptionalH5pData($h5pData, $optional, $library_name) && $valid;
    return $valid;
  }

  /**
   * Helper function for isValidH5pData
   *
   * Validates the optional part of the h5pData
   *
   * Triggers error messages
   *
   * @param array $h5pData
   *  h5p data
   * @param array $requirements
   *  Validation pattern
   * @param string $library_name
   *  Name of the library we are processing
   * @return boolean
   *  TRUE if the optional part of the $h5pData is valid
   */
  private function isValidOptionalH5pData($h5pData, $requirements, $library_name) {
    $valid = TRUE;

    foreach ($h5pData as $key => $value) {
      if (isset($requirements[$key])) {
        $valid = isValidRequirement($h5pData, $requirement, $library_name, $property_name) && $valid;
      }
      // Else: ignore, a package can have parameters that this library doesn't care about, but that library
      // specific implementations does care about...
    }

    return $valid;
  }

  /**
   * 
   *
   * @param <type> $h5pData
   * @param <type> $requirement
   * @param <type> $library_name
   * @param <type> $property_name
   * @return boolean 
   */
  private function isValidRequirement($h5pData, $requirement, $library_name, $property_name) {
    $valid = TRUE;

    if (is_string($requirement)) {
      // The requirement is a regexp, match it against the data
      if (is_string($h5pData)) {
        if (preg_match($requirement, $h5pData) === 0) {
           $this->h5pF->setErrorMessage($this->h5pF->t("Ivalid data provided for %property in %library", array('%property' => $property_name, '%library' => $library_name)));
           $valid = FALSE;
        }
      }
      else {
        $this->h5pF->setErrorMessage($this->h5pF->t("Ivalid data provided for %property in %library", array('%property' => $property_name, '%library' => $library_name)));
        $valid = FALSE;
      }
    }
    elseif (is_array($requirement)) {
      // We have sub requirements
      if (is_array($h5pData)) {
        $valid = $this->isValidRequiredH5pData($h5pData, $requirement, $library_name) && $valid;
      }
      else {
        $this->h5pF->setErrorMessage($this->h5pF->t("Ivalid data provided for %property in %library", array('%property' => $property_name, '%library' => $library_name)));
        $valid = FALSE;
      }
    }
    else {
      $this->h5pF->setErrorMessage($this->h5pF->t("Can't read the property %property in %library", array('%property' => $property_name, '%library' => $library_name)));
      $valid = FALSE;
    }
    return $valid;
  }

  private function isValidRequiredH5pData($h5pData, $requirements, $library_name) {
    $valid = TRUE;
    foreach ($requirements as $required => $requirement) {
      if (is_int($required)) {
        // We have an array of allowed options
        return isValidH5pDataOptions($h5pData, $requirements, $library_name);
      }
      if (isset($h5pData[$required])) {
        $valid = validateRequirement($h5pData[$required], $requirement, $library_name, $required) && $valid;
      }
      else {
        $this->h5pF->setErrorMessage($this->h5pF->t('The required property %property is missing from %library', array('%property' => $required, '%library' => $library_name)));
        $valid = FALSE;
      }
    }
    return $valid;
  }

  private function isValidH5pDataOptions($selected, $allowed, $library_name) {
    $valid = TRUE;
    foreach ($selected as $value) {
      if (!in_array($value, $allowed)) {
        $this->h5pF->setErrorMessage($this->h5pF->t('Illegal option %option in %library', array('%option' => $value, '%library' => $library_name)));
        $valid = FALSE;
      }
    }
    return $valid;
  }

  private function getJsonData($file_path) {
    $json = file_get_contents($file_path);
    if (!$json) {
      return FALSE;
    }
    $jsonData = json_decode($json);
    if (!$jsonData) {
      return FALSE;
    }
    return $jsonData;
  }

  private function arrayCopy(array $array) {
    $result = array();
    foreach ($array as $key => $val) {
      if (is_array($val)) {
        $result[$key] = arrayCopy($val);
      }
      elseif (is_object($val)) {
        $result[$key] = clone $val;
      }
      else {
        $result[$key] = $val;
      }
    }
    return $result;
  }

  /**
   * Recursive function for removing directories.
   *
   * @param string $dir Directory.
   * @return boolean Indicates if the directory existed.
   */
  public static function delTree($dir) {
    $files = array_diff(scandir($dir), array('.','..'));
    foreach ($files as $file) {
      (is_dir("$dir/$file")) ? delTree("$dir/$file") : unlink("$dir/$file");
    }
    return rmdir($dir);
  } 
}

class h5pSaver {
  
  public $h5pF;
  public $h5pC;

  /**
   * Constructor for the h5pSaver
   *
   * @param object $h5pFramework
   *  The frameworks implementation of the h5pFramework interface
   */
  public function __construct($h5pFramework, $h5pCore) {
    $this->h5pF = $h5pFramework;
    $this->h5pC = $h5pCore;
  }
  
  public function savePackage() {
    $jsonData = $this->h5pC->getJsonData();
    foreach ($jsonData as $key => $value) {
      if ($key == 'mainH5pData') {
        // TODO: Figure out what to do with this data
      }
      else {
        // TODO: Move the library folder
        // TODO: Store jsonData to the database
      }
    }
    // TODO: Move library folder
    // TODO: Store content.json in the database
  }
}

class h5pCore {
  public $h5pF;
  private $jsonData;

  /**
   * Constructor for the h5pSaver
   *
   * @param object $h5pFramework
   *  The frameworks implementation of the h5pFramework interface
   */
  public function __construct($h5pFramework) {
    $this->h5pF = $h5pFramework;
  }
  
  public function setJsonData($jsonData) {
    $this->$jsonData = $jsonData;
  }
  
  public function getJsonData() {
    return $jsonData;
  }
}
?>