<?php
// $Id: blocktheme.module,v 1.2 2010-12-07 00:24:49 amateescu Exp $

/**
 * @file
 * Provides a configuration option to select custom themes for blocks
 *
 * BlockTheme allows an admin to define tpl files for standard block templates
 * and provides a select box on the block configure form so the user can select
 * a tpl file to use as opposed to having to override the templates by block ID.
 *
 */

/**
 * Implementation of hook_theme()
 */
function blocktheme_theme() {
  $return = array();
  if (variable_get('blocktheme_show_custom_block_theme', '')) {
    // Override the default admin display form template
    $return['block_admin_display_form'] = array(
      'template' => 'blocktheme-admin-display-form',
    );
  }

  return $return;
}

/**
 * Implementation of hook_menu().
 */
function blocktheme_menu() {
  $items = array();
  $items['admin/settings/blocktheme'] = array(
    'title' => t('Block Theme'),
    'description' => t('Allows the admin to define re-usable block templates that can be configured from block config screen'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('blocktheme_admin_settings'),
    'access arguments' => array('administer site configuration'),
  );
  return $items;
}

/**
 * Block Theme settings page.
 */
function blocktheme_admin_settings() {
  $form = array();
  $form['blocktheme_themes'] = array(
    '#type' => 'textarea',
    '#default_value' => variable_get('blocktheme_themes', ''),
    '#title' => t('Custom Block Templates'),
    '#description' => t('Enter in the form: <em>customtemplate|Friendly Name</em> Where customtemplate corresponds to a tpl file called blocktheme-customtemplate.tpl.php as well as to the value of an extra variable <em>$blocktheme</em> in the block templates'),
    '#wysiwyg' => FALSE,
  );
  $form['blocktheme_show_custom_block_theme'] = array(
    '#type' => 'checkbox',
    '#default_value' => variable_get('blocktheme_show_custom_block_theme', ''),
    '#title' => t('Show Custom Block Theme'),
    '#description' => t('Show the custom block theme used for a block in the <a href="@block-admin-page">block admin page</a>.', array('@block-admin-page' => url('admin/build/block'))),
  );
  return system_settings_form($form);
}

/**
 * Implementation of hook_help().
 */
function blocktheme_help($path, $arg) {
  switch ($path) {
    case 'admin/help#blocktheme':
      return t('Allows the admin to define re-usable block templates that can be configured from block config screen');
      break;
    case 'admin/settings/blocktheme':
      return t('BlockTheme allows an admin to define tpl files for standard block templates and provides a select box on the block configure form so the user can select a tpl file to use as opposed to having to override the templates by block ID.');
      break;
  }
}

/**
 *  Form for updating a block
 */
function blocktheme_form_block_admin_configure_alter(&$form, &$form_state) {
  $module = $form['module']['#value'];
  $delta = $form['delta']['#value'];
  $var_name = $module .'-'. $delta;

  $options = blocktheme_get_blockthemes();
  $blocktheme = blocktheme_get();
  $blocktheme_vars = blocktheme_get_vars();

  $form['block_settings']['#weight'] = -1;
  $form['custom_block_theme'] = array(
    '#type' => 'fieldset',
    '#title' => t('Custom block theme'),
    '#weight' => 0,
    '#collapsible' => TRUE,
    '#collapsed' => FALSE,
  );
  $form['custom_block_theme']['blocktheme'] = array(
    '#type' => 'select',
    '#title' => t('Custom theme'),
    '#default_value' => $blocktheme[$var_name],
    '#options' => $options,
  );
  $form['custom_block_theme']['blocktheme_vars'] = array(
    '#type' => 'textarea',
    '#default_value' => blocktheme_format_vars_admin($blocktheme_vars[$var_name]),
    '#title' => t('Custom block variables'),
    '#description' => t('Enter one entry per line, in the format: <em>variable_name|variable_content</em>.'),
    '#wysiwyg' => FALSE,
  );

  $form['#submit'][] = 'blocktheme_update';
}

/**
 * Form for adding a new block
 */
function blocktheme_form_block_add_block_form_alter(&$form, &$form_state) {
  $options = blocktheme_get_blockthemes();

  $form['block_settings']['#weight'] = -1;
  $form['custom_block_theme'] = array(
    '#type' => 'fieldset',
    '#title' => t('Custom block theme'),
    '#weight' => 0,
    '#collapsible' => TRUE,
    '#collapsed' => FALSE,
  );
  $form['custom_block_theme']['blocktheme'] = array(
    '#type' => 'select',
    '#title' => t('Custom theme'),
    '#options' => $options,
  );
  $form['custom_block_theme']['blocktheme_vars'] = array(
    '#type' => 'textarea',
    '#default_value' => '',
    '#title' => t('Custom block variables'),
    '#description' => t('Enter one entry per line, in the format: <em>variable_name|variable_content</em>.'),
    '#wysiwyg' => FALSE,
  );

  $form['#submit'][] = 'blocktheme_save';
}

/**
 * Set Block Theme custom block settings.
 */
function blocktheme_set($blocktheme, $blocktheme_vars = NULL) {
  variable_set('blocktheme', $blocktheme);
  if ($blocktheme_vars) {
    variable_set('blocktheme_vars', $blocktheme_vars);
  }
}

/**
 * Get Block Theme custom block settings.
 */
function blocktheme_get() {
  static $blocktheme;
  if (empty($blocktheme)) {
    $blocktheme = variable_get('blocktheme', array());
  }

  return $blocktheme;
}

/**
 * Get Block Theme custom block variables settings.
 */
function blocktheme_get_vars() {
  static $blocktheme_vars;
  if (empty($blocktheme_vars)) {
    $blocktheme_vars = variable_get('blocktheme_vars', array());
  }

  return $blocktheme_vars;
}

/**
 * Update an existing block after the block form has been submitted
 */
function blocktheme_update($form_id, &$form_state) {
  $var_name = $form_state['values']['module'] .'-'.  $form_state['values']['delta'];

  $blocktheme = blocktheme_get();
  $blocktheme_vars = blocktheme_get_vars();

  if (!$form_state['values']['blocktheme']) {
    unset($blocktheme[$var_name]);
  }
  else {
    $blocktheme[$var_name] = $form_state['values']['blocktheme'];
  }
  if (!$form_state['values']['blocktheme_vars']) {
    unset($blocktheme_vars[$var_name]);
  }
  else {
    $blocktheme_vars[$var_name] = blocktheme_format_vars($form_state['values']['blocktheme_vars']);
  }
  blocktheme_set($blocktheme, $blocktheme_vars);
}

/**
 *  Save a new block after form was submitted
 */
function blocktheme_save($form_id, &$form_state) {
  // First, get the new delta value
  $result = db_query("SELECT delta FROM {blocks} WHERE bid = '%s'", db_last_insert_id('boxes', 'bid'));
  if ($delta_result = db_fetch_object($result)) {
    $delta = $delta_result->delta;
    $var_name = $form_state['values']['module'] .'-'.  $delta;

    $blocktheme = blocktheme_get();
    $blocktheme_vars = blocktheme_get_vars();

    if ($form_state['values']['blocktheme']) {
      $blocktheme[$var_name] = $form_state['values']['blocktheme'];
    }
    if ($form_state['values']['blocktheme_vars']) {
      $blocktheme_vars[$var_name] = blocktheme_format_vars($form_state['values']['blocktheme_vars']);
    }
    blocktheme_set($blocktheme, $blocktheme_vars);
  };
}

/**
 * Get the defined blockthemes and return an array to be used in a select list.
 */
function blocktheme_get_blockthemes() {
  $options = array();
  $blockthemes = variable_get('blocktheme_themes', '');

  $options[] = t('- None -');

  if ($blockthemes) {
    $_sets = explode("\n", $blockthemes);

    foreach ($_sets as $key => $value) {
      $set = explode('|', $value);
      $options[$set[0]] = $set[1];
    }
  }

  return $options;
}

/**
 *  Formats custom variables as an array to be used in the block template.
 */
function blocktheme_format_vars($block_vars) {
  $formatted_vars = array();
  if ($block_vars) {
    $_sets = explode("\n", $block_vars);
    foreach ($_sets as $key => $value) {
      $set = explode('|', $value);
      $formatted_vars[$set[0]] = $set[1];
    }
  }

  return $formatted_vars;
}

/**
 *  Formats custom variables for displaying in a block configuration form.
 */
function blocktheme_format_vars_admin($block_vars) {
  $formatted_vars = '';
  if ($block_vars) {
    foreach ($block_vars as $key => $value) {
      $_formatted_vars[] = $key .'|'. $value;
    }
    $formatted_vars = implode("\n", $_formatted_vars);
  }

  return $formatted_vars;
}

/**
 *  Get custom theme for a block.
 */
function blocktheme_get_theme($block) {
  $blocktheme = blocktheme_get();
  $var_name = $block->module .'-'. $block->delta;
  if (isset($blocktheme[$var_name])) {
    return $blocktheme[$var_name];
  }
}

/**
 *  Get custom variables for a block.
 */
function blocktheme_get_theme_vars($block) {
  $blocktheme_vars = blocktheme_get_vars();
  $var_name = $block->module .'-'. $block->delta;
  if (isset($blocktheme_vars[$var_name])) {
    return $blocktheme_vars[$var_name];
  }
}

/**
 * Implementation of hook_preprocess_block().
 */
function blocktheme_preprocess_block(&$vars) {
  if ($custom_block_theme = blocktheme_get_theme($vars['block'])) {
    // Added for downward compatibility:
    // Remove blocktheme- prefix if present
    // Maybe use an update instead?
    $len = drupal_strlen('blocktheme-');
    if (strncmp($custom_block_theme, 'blocktheme-', $len) == 0) {
      $custom_block_theme = drupal_substr($custom_block_theme, $len);
    }
    $vars['blocktheme'] = $custom_block_theme;
    $vars['template_files'][] = 'blocktheme-' . $custom_block_theme;
    // Added for backward compatibility
    $vars['template_files'][] = $custom_block_theme;
  }

  if ($custom_block_vars = blocktheme_get_theme_vars($vars['block'])) {
    $vars['blocktheme_vars'] = $custom_block_vars;
  }
}

/**
 * Implementation of template_preprocess_block_admin_display_form().
 */
function blocktheme_preprocess_block_admin_display_form(&$variables) {
  if (variable_get('blocktheme_show_custom_block_theme', '')) {
    // Get blocks with custom templates.
    $blocktheme = blocktheme_get();
    // Get block theme names.
    $blocktheme_themes = blocktheme_get_blockthemes();

    foreach (element_children($variables['form']) as $i) {
      $block = &$variables['form'][$i];

      // Only take form elements that are blocks.
      if (isset($block['info'])) {
        // Fetch region for current block.
        $region = $block['region']['#default_value'];
        // Set block theme key for the current module.
        $var_name = $block['module']['#value'] .'-'. $block['delta']['#value'];

        $variables['block_listing'][$region][$i]->custom_block_theme = (isset($blocktheme[$var_name])) ? $blocktheme_themes[$blocktheme[$var_name]] : '';
      }
    }
  }
}

// @todo: Is it better to unserialize a huge array, or to use a hacky string based namespace?