<?php

/**
* Automate the generation of a menu tree for the process
*/
function wizard_build_menu($module, $proc, $name = null, $path = null, $callback = 'wizard_callback', $access = TRUE) {
  $links = array();
  $path = ($path != null) ? trim($path, '/') : $module .'/'. $proc;

  $processes =  module_invoke($module, 'wizards', $proc);

  //for sequential weighting.
  $i = 0;  

  if (is_array($processes)) {
    $links[] = array('path' => $path, 'title' => (($name) ? $name : $module . ' wizard'), 'callback' => $callback, 'weight' => -5, 'access' => $access); 
    foreach (array_keys($processes) as $op) {
      //TODO: specify a mechanism to allow an alternate tree creation schema
      $links[] = array('path' => $path .'/'. $op, 'title' => $processes[$op], 'callback' => $callback, 'weight' => $i++, 'access' => $access);
    }
  }

  return $links;
}

/**
* This function seperates the default wizard menu construction.
* this allows us to change the location of the wizard, and other important things
*/
function wizard_callback() {
  $path = trim(str_replace(arg(0) . "/" . arg(1) , "", $_GET["q"]), "/");
  $module = arg(0);
  $proc = arg(1);

  return wizard_page($module, $proc, $path);
}

function _wizard_next($wizards_array, $path_present) {
  $paths = array_keys($wizards_array);
  if ($path_present) {
    $paths = array_keys($wizards_array);
    $paths_flipped = array_flip($paths);
    $index = $paths_flipped[$path_present];
    return $paths[$index + 1];
  }
  else {
   return $paths[0];
  }
}

/**
* Generate a page for the wizard. 
*/

function wizard_page($module, $proc, $path, $mount = "") {
  if ($path == $_POST['edit']['wizard_history']) {
    $_SESSION['wizard'][$module][$path] = ($_SESSION['wizard'][$module][$path] == null) ? array() : $_SESSION['wizard'][$module][$path];

    $_SESSION["wizard"][$module][$path] = array_merge($_SESSION["wizard"][$module][$path], (array)$_POST["edit"]);
  }
  
  $screens = module_invoke($module, "wizards", $proc);
  
  $mount = ($mount != null) ? trim($mount, "/") : "$module/$proc";
  $process_page = $module . "_process_" . $proc;

  if (isset($_POST["wizard_back"])) {
    drupal_goto("$mount/" . $_POST["edit"]["wizard_previous"]);
  }


  if (isset($_POST["wizard_forward"])) {
    $wizard_next = _wizard_next($screens, $path);
    //if ($_POST["edit"]["wizard_next"]) {
    //  drupal_goto("$mount/" . $_POST["edit"]["wizard_next"]);
    //}
    if ($wizard_next) {
      drupal_goto("$mount/" . $wizard_next);
    }
    else {
      $_SESSION["wizard"]["completed"][$module] = true;
      drupal_goto($mount);
    }
  }
 
  //Where we are coming from after submission
  $form .= form_hidden("wizard_history", $path);

  $screenpath = array_keys($screens); 

  //completed the form, unless told otherwise
  $completed = true;
  if (empty($path)) {
    if ($_SESSION["wizard"]["completed"][$module]) {
      //form has been completed
      //Run through all screens, only calling the execute op, if it validates
       
      foreach ($screenpath as $screen) {
        $nextkey++;
        $defaults = wizard_invoke_screen($module, $screen, $edit, "defaults");
   
        $defaults = is_array($defaults) ? $defaults : array();

        $_SESSION["wizard"][$module][$screen] = (is_array($_SESSION["wizard"][$module][$screen])) ? $_SESSION["wizard"][$module][$screen] : array();

        $edit = array_merge($defaults, $_SESSION["wizard"][$module][$screen]);

        if (wizard_invoke_screen($module, $screen, $edit, "validate") != true) {
          // Validation failed, go back to screen and try again
          drupal_goto("$mount/$screen");
        }
        else {
          // Call the execute operation, making the database modifications
          wizard_invoke_screen($module, $screen, $edit, "execute");
        }
      
      }
      
      if (function_exists($process_page)) {
        call_user_func($process_page, "execute");
        $form .= call_user_func($process_page, "completed");
      }
      else {
        $form .= t("<p>Thank you for completing this wizard, you may continue</p>");
      }

      unset($_SESSION["wizard"]["completed"][$module]);

    }
    else {
      // display form introduction
      $completed = false;
      $nextkey = 0;
      if (function_exists($process_page)) {
        $form .= call_user_func($process_page, "introduction");
      }
      else {
        $form .= t("<p>Welcome to this wizard. please continue</p>");
      }
      
    }

    $output = $form;
  }
  else {
    $nextkey = 0;
    foreach ($screenpath as $screen) {      
      $nextkey++;
      
      $defaults = wizard_invoke_screen($module, $screen, $edit, "defaults");
      $defaults = is_array($defaults) ? $defaults : array();

      $_SESSION["wizard"][$module][$screen] = (($_SESSION["wizard"][$module][$screen]) != NULL) ? $_SESSION["wizard"][$module][$screen] : array();

      $edit = array_merge($defaults, $_SESSION["wizard"][$module][$screen]);

      if ($path == $screen) {
        $form .= wizard_invoke_screen($module, $screen, $edit, "form");
        $completed = false;
        break; // could be dangerous
      }
      elseif (wizard_invoke_screen($module, $screen, $edit, "validate") != true) {
        if ($path != $screen) {
          drupal_goto("$mount/$screen");
        }
        $form .= wizard_invoke_screen($module, $screen, $edit, "form");
        $completed = false;
        break; // could be dangerous 
      }
    }
  }
 
  //
  // Display the buttons at the bottom of the page
  //
  $previous = ($nextkey - 2);
  if (!$completed) {
    if ($previous >= 0) {
      $buttons .= form_button("Back", "wizard_back");
      $buttons .= form_hidden("wizard_previous", $screenpath[$previous]);
    }
    $buttons .= form_button("Next", "wizard_forward");
    $buttons .= form_hidden("wizard_next", $screenpath[$nextkey]);

    $form .= $buttons;

    $output = form($form, "post");
  }
  print theme("page", $output, $screens[$path]);
}

function wizard_invoke_screen($module, $path, $edit, $op) {
  $split = explode("/",  str_replace("#","", $path));
  
  for ($x = sizeof($split); $x >= 0; $x--) {
    $func =  implode("_", array_merge( array($module . "_wizard"), array_slice($split, 0, $x)));
    if (function_exists($func)) {
      return $func($path, $edit ,$op);
   }
  }
}

?>