<?php
/**
 * Finite state machine writer.
 *
 * Keeping the FSM writer (generation) functions out of the root class minimizes
 * the code volume for FSM readers, which should represent the majority of FSM
 * users.
 *
 * @copyright  (c) 2007-2012 Ouest Systèmes Informatiques
 * @author     Frédéric G. MARAND
 * @license    Licensed under the CeCILL 2.0
 * @link       http://wiki.audean.com/fsm/fsm
 */

namespace OSInet\Finite_State_Machine;

/**
 * Needed notably for func_name()
 */
require_once('misc.php');

$erFiniteStateMachine = error_reporting(E_ALL|E_STRICT);

/**
 * Read/Write concrete FSM class.
 *
 * This (concrete) class extends the default abstract Finite_State_Machine to
 * add write behaviours. It is to be used by applications wishing to write FSM
 * files. Other applications should not use it to avoid code bloat.
 */
class Writer extends Machine {

  const FORMAT_VERSION = '1.1';

  public function __construct() {
    $this->fTransitions = array();
    parent::__construct();
  }

  /**
   * Return the initial and final states from an abstract FSM graph.
   *
   * @param array $graph
   *   A concrete FSM derived from the abstract FSM.
   *
   * @return array
   */
  protected function getSpecialStates($graph) {
    $ret = array(NULL, NULL);
    foreach ($graph['states'] as $state) {
      if (isset($state['type']) && $state['type'] == 'initial') {
        $ret[0]  = $state['name'];
      }
      if (isset($state['type']) && $state['type'] == 'final') {
        $ret[1]  = $state['name'];
      }
      if (isset($ret[0]) && isset($ret[1])) {
        break;
      }
    }
    return $ret;
  }

  /**
   * Return the transitions (triggers) available from a given state
   *
   * @param array $graph
   *   A concrete Machine.
   * @param string $id
   *   State id in the abstract graph (not id in the XML FSM).
   *
   * @return array
   */
  protected function getTransitionsForState($graph, $id) {
    $ret = array();
    foreach ($graph['transitions'] as $txid => $transition) {
      // echo "id = $id, txid = $txid from = " . $transition['from'] . PHP_EOL;
      if ($transition['from'] == $id) {
        $ret[] = $txid;
      }
    }
    return $ret;
  }

  /**
   * Generate the XML FSM file and optionally PHP stubs file.
   *
   * Source is an abstract FSM representation as an array of states/transitions.
   *
   * @param array $graph
   * @param string $prefix
   * @param boolean $php
   * @param boolean $overwrite
   *
   * @todo take $overwrite and $php into account
   *
   * @deprecated
   */
  public function oldSaveFsm($graph, $prefix = 'fsm', $php = FALSE, $overwrite = FALSE) {
    echo "This is a dump for FSM $prefix"
      . ', ' . ($php ? 'with' : 'without') . ' PHP generation'
      . ', ' . ($overwrite ? 'with' : 'without') . ' overwrite mode'
      . ".\n";

    $doc = new DOMDocument('1.0', 'utf-8');
    $comment = new DOMComment(' Generated by '
      . basename(__FILE__, '.php')
      . " version " . Fsm_Writer::VERSION
      . " ");
    $doc->appendChild($comment);
    $fsm = new DOMElement('fsm');
    $doc->appendChild($fsm);
    $fsm->setAttribute('fsm_version',   "1.3");
    $fsm->setAttribute('idle_work',     "1");
    $fsm->setAttribute('allow_actions', "1");
    list($init, $final) = $this->getSpecialStates($graph);
    $fsm->setAttribute('init', $init);
    $fsm->setAttribute('final', $final);

    foreach ($graph['states'] as $id => $state) {
      $state_node = new DOMElement('state');
      $fsm->appendChild($state_node);
      // setIdAttribute not yet implemented in php 5.1
      $state_node->setAttribute('id', $state['name']);
      $transitions = $this->getTransitionsForState($graph, $id);

      /**
       * FGM on ne peut pas simplement boucler ainsi: on a dans le graphe
       * abstrait une transition par évènement, alors que dans la FSM les
       * transitions partant du même état sont groupées. En se contentant
       * de boucler ainsi, on crée un "event" pour chaque transition alors
       * qu'il faut créer 1 event et "n" next.
       */
      foreach ($transitions as $transition_id) {
        $event_node = new DOMElement('event');
        $state_node->appendChild($event_node);
        $transition = $graph['transitions'][$transition_id];
        $event_node->setAttribute('name', $transition['trigger']);
        /**
         * @todo support other event types
         */
        $event_node->setAttribute('type', 'string');
      }
    }
    $doc->save("$prefix.xml");
    print_r($graph['transitions']);
  }

  /**
   * Add a new state to the transitions table.
   *
   * @param string $name
   *
   * @return integer 0 on success, < 0 on failure
   */
  public function addState($name) {
    // echo func_name() . "($name)";

    if (array_key_exists($name, $this->fTransitions)) {
      $ret = -1;
    }
    else {
      $this->fTransitions[$name] = array();
      $ret = 0;
    }
    // echo ", ret = $ret\n";
    return $ret;
  }

  /**
   * Add an event definition (name + optional type of handler) to an existing state
   *
   * @param string $state
   * @param string $event
   * @param string $type
   *
   * @return integer
   *   - 0 on success
   *   - < 0 on failure
   */
  public function addEvent($state, $event, $type = 'string') {
    if (!array_key_exists($state, $this->fTransitions)) {
      $ret = -1;
    }
    elseif (array_key_exists($event, $this->fTransitions[$state])) {
      $ret = -2;
    }
    // state exists, event doesn't: OK
    else {
      $this->fTransitions[$state][$event] = array();
      $this->fTransitions[$state][$event]["#type"] = $type;
      $ret = 0;
    }

    return $ret;
  }

  /**
   * Add an outcome definition to an existing event:
   * - event handler result
   * - next state
   * - event to fire after transition to next state
   * All outcome fields are optional
   *
   * @param name $state
   * @param name $event
   *
   * @return integer
   *   - 0 on success
   *   - < 0 on failure
   */
  public function addOutcome($state, $event,
    $result     = NULL,  // if null, single possible outcome; only possible on void events
    $next_state = NULL,  // if null, stay on same state
    $action     = NULL)  // if null, do not send an event after transitioning
    {
    $t = &$this->fTransitions;
    if (!array_key_exists($state, $t)) {
      $ret = -1;
    }
    elseif (!array_key_exists($event, $t[$state])) {
      $ret = -2;
    }
    elseif (($result == NULL) && ($t[$state][$event]['#type'] <> 'void')) {
      $ret = -3; // Undefined, single, results are only available for void events
    }
    elseif (($result != NULL) && array_key_exists($result, $t[$state][$event])) {
      $ret = -4; // results must be unique per event
    }
    else {
      $t[$state][$event][$result] = array($next_state, $action);
      $ret = 0;
    }
    return $ret;
  }

  /**
   * Defines the special states in the FSM
   *
   * @param string $kind Finite_State_Machine::INIT_STATE or ..FINAL_STATE
   * @param string $name
   */
  public function setSpecialState($kind, $name) {
    // echo func_name() . "($kind, $name)\n";
    if (($kind != Machine::INIT_STATE) && ($kind != Machine::FINAL_STATE)) {
      $ret = -1; // unknown special state
    }
    elseif (!array_key_exists($name, $this->fTransitions)) {
      $ret = -2; // non existent state declared as special
    }
    else {
      $this->fTransitions["#$kind"] = $name;
      $ret = 0;
    }
    return $ret;
  }

  /*
   * Generate the XML FSM file and optionally PHP stubs file.
   *
   * Source is a valid instance of FSM.
   *
   * @param string $prefix
   * @param boolean $php
   * @param boolean $overwrite
   *
   * @todo take $overwrite and $php into account
   *
   * @throws Exception from within checkTransitions
   */
  public function saveFsm($prefix = 'fsm', $php = FALSE, $overwrite = FALSE) {
    $this->checkTransitions();

    $t = &$this->fTransitions;
    echo "This is a dump for FSM $prefix"
      . ', ' . ($php ? 'with' : 'without') . ' PHP generation'
      . ', ' . ($overwrite ? 'with' : 'without') . ' overwrite mode'
      . ".\n";

    $doc = new DOMDocument('1.0', 'utf-8');
    $comment = new DOMComment(' Generated by '
      . basename(__FILE__, '.php')
      . " version " . Writer::FORMAT_VERSION
      . " on FSM version " . Machine::VERSION
      . " ");
    $doc->appendChild($comment);
    $fsm = new DOMElement('fsm');
    $doc->appendChild($fsm);
    $fsm->setAttribute('fsm_version',   "1.3");
    $fsm->setAttribute('idle_work',     "1");
    $fsm->setAttribute('allow_actions', "1");

    $fsm->setAttribute('init',  $t['#' . Machine::INIT_STATE]);
    $fsm->setAttribute('final', $t['#' . Machine::FINAL_STATE]);

    foreach ($this->fTransitions as $stateName => $state) {
      if ($stateName[0] == '#') {
        continue; // ignore special state definitions
      }
      $stateNode = new DOMElement('state', "\n");
      $fsm->appendChild($stateNode);
      $stateNode->setAttribute('id', $stateName);
      foreach ($state as $eventName => $event) {
        $eventNode = new DOMElement('event', "\n");
        $stateNode->appendChild($eventNode);
        $eventNode->setAttribute('name', $eventName);
        $eventNode->setAttribute('type', $event['#type']);
        foreach ($event as $outcomeName => $outcome) {
          if ($outcomeName[0] == '#') {
            continue; // ignore special outcome definitions (event type)
          }
          $outcomeNode = new DOMElement('next', "\n");
          $eventNode->appendChild($outcomeNode);
          /**
           * Generated FSMs currently always use the "string" event handler type,
           * meaning they always have outcome results. This will not always be
           * the case, hence this test (think ftp.xml)
           */
          if (!empty($outcomeName)) {
            $outcomeNode->setAttribute('result', $outcomeName);
          }

          if (!empty($outcome[0])) {
            $outcomeNode->setAttribute('state', $outcome[0]);
          }

          if (!empty($outcome[1])) {
            $outcomeNode->setAttribute('action', $outcome[1]);
          }
        }
      }
    }

    $doc->save("$prefix.xml");
  }
}