<?php
class csElementsContainer extends csBaseElement
{

  /**
   * Definitions container
   * @var array
   */
  protected $definitions = array();

  /**
   * Elements container
   * @var array
   */
  protected $elements = array();

  /**
   * Used definitions
   * @var array
   */
  protected $used_definitions = array();

  /**
   * DOM ids
   * @var array
   */
  protected $dom_ids = array();

  /**
   * Adds a definition to current SVG Document
   *
   * @param  mixed  $definition  SVG definition to add
   * @param  string $id          Override element DOM id
   * TODO: implement definitions and references
   */
  public function addAsDefinition($definition, $id = null)
  {
    $is_element = is_callable(array($definition, 'setId'));
    if (is_string($id) && trim($id) != '' && $is_element)
    {
      $definition->setId($id);
    }
    $id = $definition->getId();
    if (is_null($id))
    {
      throw new csException(
                  sprintf('A definition must have an id specified'));
    }
    elseif ($this->hasId($id))
    {
      throw new csException(
                  sprintf('The DOM id "%s" has been already defined', $id));
    }
    else
    {
      $this->definitions[$id] = $definition;
      $this->dom_ids[] = $id;
    }
  }

  /**
   * Adds a SVG shape or group to current SVG Document at a certain depth
   *
   * @param  mixed    $element  SVG element to add
   * @throws csException
   */
  public function addElement($element)
  {
    // Add DOM id to document list, if any
    $id = $element->getId();
    if (!is_null($id))
    {
      if ($this->hasId($id))
      {
        throw new csException(
          sprintf('Document has already an element with id "%s"', $id));
      }
      $this->dom_ids[] = $id;
    }
    $this->elements[] = $element;
  }

  /**
   * Create an svg element and returns its instance
   *
   * @param  string $name
   * @return csBaseElement
   */
  public function createElement($name)
  {
    $class_name = sprintf('cs%s', ucfirst($name));
    if (!class_exists($class_name))
    {
      throw new csException(sprintf('Element class "%s" does not exist',
                                   $class_name));
    }
    return new $class_name;
  }

  /**
   * Drop an element from container by its DOM id
   *
   * @param  string  $id
   * @throws csException
   */
  public function dropElementById($id)
  {
    foreach ($this->getElements() as $index => $element)
    {
      if ($element->getId() == $id)
      {
        foreach ($this->dom_ids as $dom_index => $dom_id)
        {
          if ($dom_id == $id)
          {
            unset($this->dom_ids[$dom_index]);
          }
        }
        unset($this->elements[$index]);
        return;
      }
    }
  }

  /**
   * Returns a defined element alias (a &lt;use/&gt; tag)
   *
   * @param  string  $id
   * @return array
   * @throws csException
   */
  public function getDefinition($id)
  {
    if (!isset($this->definitions[$id]))
    {
      throw new csException(
                  sprintf('Unable to find id "%s" in current document.'));
    }
    else
    {
      return $this->definitions[$id];
    }
  }

  /**
   * Retrieves container definitions
   *
   * @return array
   */
  public function getDefinitions()
  {
    return $this->definitions;
  }

  /**
   * Retrieve an element instance by its DOM id
   *
   * @param  string  $id
   * @return csBaseElement
   */
  public function getElementById($id)
  {
    $container_types = array('elements', 'definitions');
    $found_element = null;
    foreach ($container_types as $container_type)
    {
      if (!property_exists($this, $container_type))
      {
        return;
      }
      foreach ($this->$container_type as $element)
      {
        if ($element->getId() == $id)
        {
          $found_element = $element;
          break;
        }
        elseif ($element instanceof csElementsContainer)
        {
          $found_element = $element->getElementById($id);
          if (!is_null($found_element))
          {
            break;
          }
        }
      }
    }
    return $found_element;
  }

  /**
   * Rerieves container elements
   *
   * @return array
   */
  public function getElements()
  {
    return $this->elements;
  }

  /**
   * Returns an array containing used definitions for current document
   *
   * @return array
   */
  public function getUsedDefinitions()
  {
    return $this->used_definitions;
  }

  /**
   * Checks if container has an element with given id in it
   *
   * @param  string  $id
   * @return boolean
   */
  public function hasId($id)
  {
    return !is_null($this->getElementById($id));
  }

  /**
   * Process definitions if any
   *
   * @param  DOMDocument  $dom
   */
  public function processDefinitions(DOMDocument $dom)
  {
    if (count($this->getDefinitions()) > 0)
    {
      // Definitions declaration
      $defs_node = $dom->createElement(csDocument::getNodeNS().'defs');
      foreach ($this->getDefinitions() as $definition)
      {
        // Define elements
        $definition_node = $definition->compile(csDocument::getIsEmbedded());
        $def_node = $dom->importNode($definition_node, true);
        $defs_node->appendChild($def_node);
      }
      $dom->documentElement->appendChild($defs_node);
    }
  }

  /**
   * Process Document elements
   *
   * @param  DOMDocument  $dom
   */
  public function processElements(DOMDocument $dom)
  {
    foreach ($this->getElements() as $element)
    {
      $element_node = $element->compile(csDocument::getIsEmbedded());
      $node_element = $dom->importNode($element_node, true);
      $dom->documentElement->appendChild($node_element);
    }
  }

  /**
   * Process used definitions, if any
   *
   * @param  DOMDocument  $dom
   */
  public function processUsedDefinitions(DOMDocument $dom)
  {
    if (count($this->getUsedDefinitions()) > 0)
    {
      foreach ($this->getUsedDefinitions() as $used_definition)
      {
        $element = $used_definition[0];
        $attributes = $used_definition[1];
        $use_node = $dom->createElement(csDocument::getNodeNS().'use');
        $use_node->setAttribute('xlink:href', '#'.$element->getId());
        foreach ($attributes as $attr_name => $attr_value)
        {
          $use_node->setAttribute($attr_name, $attr_value);
        }
        $dom->documentElement->appendChild($use_node);
      }
    }
  }

  /**
   * Swap respective depths of two elements. Both elements are retrieved by
   * their DOM id.
   *
   * @param  string $id1
   * @param  string $id2
   * @throws csException
   */
  public function swapDepths($id1, $id2)
  {
    if ($id1 == $id2)
    {
      return;
    }
    $e1 = $this->getElementById($id1);
    $e2 = $this->getElementById($id2);
    $e1depth = $e1->getDepth();
    $e2depth = $e2->getDepth();
    $e2->setDepth($e1depth);
    $e1->setDepth($e2depth);
    $this->dropElementById($id1);
    $this->dropElementById($id2);
    $this->addElement($e1, $e1depth, true);
    $this->addElement($e2, $e2depth, true);
  }

  /**
   * Uses a definition in current SVG Document
   *
   * @param  mixed  $element
   * @param  array  $attrs    More atributes to add to &lt;use/&gt; tag
   */
  public function useDefinition($id, $attrs = array())
  {
    $this->used_definitions[] = array($this->getDefinition($id), $attrs);
  }

}