<?php
// $Id$

/**
 * Implementation of hook_form_alter().
 */
function color_form_alter($form_id, &$form) {
  // Insert the color changer into the theme settings page.
  // TODO: Last condition in the following if disables color changer when private files are used this should be solved in a different way. See issue #92059.
  if ($form_id == 'system_theme_settings' && color_get_info(arg(4)) && function_exists('gd_info') && variable_get('file_downloads', FILE_DOWNLOADS_PUBLIC) == FILE_DOWNLOADS_PUBLIC) {
    $form['color'] = array(
      '#type' => 'fieldset',
      '#title' => t('Color scheme'),
      '#weight' => -1,
      '#attributes' => array('id' => 'color_scheme_form'),
      '#theme' => 'color_scheme_form',
    );
    $form['color'] += color_scheme_form(arg(4));
    $form['#submit']['color_scheme_form_submit'] = array();
  }

  // Use the generated screenshot in the theme list
  if ($form_id == 'system_theme_select_form' || $form_id == 'system_themes') {
    $themes = list_themes();
    foreach (element_children($form) as $theme) {
      if ($screenshot = variable_get('color_'. $theme .'_screenshot', NULL)) {
        if (isset($form[$theme]['screenshot'])) {
          $form[$theme]['screenshot']['#value'] = theme('image', $screenshot, '', '', array('class' => 'screenshot'), FALSE);
        }
      }
    }
  }
}

/**
 * Callback for the theme to alter the resources used.
 */
function _color_page_alter(&$vars) {
  global $theme_key;

  // Override stylesheet
  $path = variable_get('color_'. $theme_key .'_stylesheet', NULL);
  if ($path) {
    $vars['css']['theme'] = array($path => array('path' => $path, 'media' => 'all'));
    $vars['styles'] = drupal_get_css($vars['css']);
  }

  // Override logo
  $logo = variable_get('color_'. $theme_key .'_logo', NULL);
  if ($logo && $vars['logo'] && preg_match('!'. $theme_key .'/logo.png$!', $vars['logo'])) {
    $vars['logo'] = base_path() . $logo;
  }
}

/**
 * Retrieve the color.module info for a particular theme.
 */
function color_get_info($theme) {
  $path = drupal_get_path('theme', $theme);
  $file = $path .'/color/color.inc';
  if ($path && file_exists($file)) {
    include $file;
    return $info;
  }
}

/**
 * Helper function to retrieve the color palette for a particular theme.
 */
function color_get_palette($theme, $default = false) {
  // Fetch and expand default palette
  $fields = array('base', 'link', 'top', 'bottom', 'text');
  $info = color_get_info($theme);
  $keys = array_keys($info['schemes']);
  foreach (explode(',', array_shift($keys)) as $k => $scheme) {
    $palette[$fields[$k]] = $scheme;
  }

  // Load variable
  return $default ? $palette : variable_get('color_'. $theme .'_palette', $palette);
}

/**
 * Form callback. Returns the configuration form.
 */
function color_scheme_form($theme) {
  $base = drupal_get_path('module', 'color');
  $info = color_get_info($theme);

  // Add Farbtastic color picker
  drupal_add_css('misc/farbtastic/farbtastic.css');
  drupal_add_js('misc/farbtastic/farbtastic.js');

  // Add custom CSS/JS
  drupal_add_css($base .'/color.css', 'module');
  drupal_add_js($base .'/color.js');
  drupal_add_js(array('color' => array(
    'reference' => color_get_palette($theme, true)
  )), 'setting');

  // See if we're using a predefined scheme
  $current = implode(',', variable_get('color_'. $theme .'_palette', array()));
  // Note: we use the original theme when the default scheme is chosen.
  $current = isset($info['schemes'][$current]) ? $current : ($current == '' ? reset($info['schemes']) : '');

  // Add scheme selector
  $info['schemes'][''] = t('Custom');
  $form['scheme'] = array(
    '#type' => 'select',
    '#title' => t('Color set'),
    '#options' => $info['schemes'],
    '#default_value' => $current,
  );

  // Add palette fields
  $palette = color_get_palette($theme);
  $names = array(
    'base' => t('Base color'),
    'link' => t('Link color'),
    'top' => t('Header top'),
    'bottom' => t('Header bottom'),
    'text' => t('Text color')
  );
  $form['palette']['#tree'] = true;
  foreach ($palette as $name => $value) {
    $form['palette'][$name] = array(
      '#type' => 'textfield',
      '#title' => $names[$name],
      '#default_value' => $value,
      '#size' => 8,
    );
  }
  $form['theme'] = array('#type' => 'value', '#value' => arg(4));
  $form['info'] = array('#type' => 'value', '#value' => $info);

  return $form;
}

/**
 * Theme color form.
 */
function theme_color_scheme_form($form) {
  // Include stylesheet
  $theme = $form['theme']['#value'];
  $info = $form['info']['#value'];
  $path = drupal_get_path('theme', $theme) .'/';
  drupal_add_css($path . $info['preview_css']);

  // Wrapper
  $output .= '<div class="color-form clear-block">';

  // Color Schemes
  $output .= drupal_render($form['scheme']);

  // Palette
  $output .= '<div id="palette" class="clear-block">';
  foreach (element_children($form['palette']) as $name) {
    $output .= drupal_render($form['palette'][$name]);
  }
  $output .= '</div>';

  // Preview
  $output .= drupal_render($form);
  $output .= '<h2>'. t('Preview') .'</h2>';
  $output .= '<div id="preview"><div id="text"><h2>Lorem ipsum dolor</h2><p>Sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud <a href="#">exercitation ullamco</a> laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p></div><div id="img" style="background-image: url('. base_path() . $path . $info['preview_image'] .')" alt="" /></div></div>';

  $output .= '</div>';

  return $output;
}

/**
 * Submit handler for color change form.
 */
function color_scheme_form_submit($form_id, $values) {
  // Get theme coloring info
  if (!isset($values['info'])) {
    return;
  }
  $theme = $values['theme'];
  $info = $values['info'];

  // Resolve palette
  $palette = $values['palette'];
  if ($values['scheme'] != '') {
    $scheme = explode(',', $values['scheme']);
    foreach ($palette as $k => $color) {
      $palette[$k] = array_shift($scheme);
    }
  }

  // Delete old files
  foreach (variable_get('color_'. $theme .'_files', array()) as $file) {
    @unlink($file);
  }
  if ($file = dirname($file)) {
    @rmdir($file);
  }

  // Don't render the default colorscheme, use the standard theme instead.
  if (implode(',', color_get_palette($theme, true)) == implode(',', $palette)
    || $values['op'] == t('Reset to defaults')) {
    variable_del('color_'. $theme .'_palette');
    variable_del('color_'. $theme .'_stylesheet');
    variable_del('color_'. $theme .'_logo');
    variable_del('color_'. $theme .'_files');
    variable_del('color_'. $theme .'_screenshot');
    return;
  }

  // Prepare target locations for generated files
  $id = $theme .'-'. substr(md5(serialize($palette) . microtime()), 0, 8);
  $paths['color'] = variable_get('file_directory_path', 'files') .'/color';
  $paths['target'] = $paths['color'] .'/'. $id .'/';
  foreach ($paths as $path) {
    if (!is_dir($path)) {
      mkdir($path);
    }
  }
  $paths['id'] = $id;
  $paths['source'] = drupal_get_path('theme', $theme) .'/';
  $paths['stylesheet'] = $paths['target'] .'style.css';
  $paths['files'] = $paths['map'] = array();

  // Save palette and stylesheet location
  variable_set('color_'. $theme .'_palette', $palette);
  variable_set('color_'. $theme .'_stylesheet', $paths['stylesheet']);
  variable_set('color_'. $theme .'_logo', $paths['target'] .'logo.png');

  // Copy over neutral images
  foreach ($info['copy'] as $file) {
    $base = basename($file);
    copy($paths['source'] . $file, $paths['target'] . $base);
    $paths['map'][$file] = $base;
    $paths['files'][] = $paths['target'] . $base;
  }

  // Render new images
  _color_render_images($theme, $info, $paths, $palette);

  // Rewrite stylesheet
  _color_rewrite_stylesheet($theme, $info, $paths, $palette);

  // Maintain list of files
  variable_set('color_'. $theme .'_files', $paths['files']);
}

/**
 * Rewrite the stylesheet to match the colors in the palette.
 */
function _color_rewrite_stylesheet($theme, &$info, &$paths, $palette) {
  // Load stylesheet
  $style = file_get_contents($paths['source'] .'style.css');

  // Prepare color conversion table
  $conversion = $palette;
  unset($conversion['base']);
  foreach ($conversion as $k => $v) {
    $conversion[$k] = drupal_strtolower($v);
  }
  $default = color_get_palette($theme, true);

  // Split off the "Don't touch" section of the stylesheet.
  list($style, $fixed) = explode("Color Module: Don't touch", $style);

  // Look for @import commands and insert the referenced stylesheets.
  $cwd = getcwd();
  chdir(drupal_get_path('theme', $theme));
  $style = preg_replace_callback('/@import\s*["\']([^"\']+)["\'];/', '_color_import_stylesheet', $style);
  chdir($cwd);

  // Find all colors in the stylesheet and the chunks in between.
  $style = preg_split('/(#[0-9a-f]{6}|#[0-9a-f]{3})/i', $style, -1, PREG_SPLIT_DELIM_CAPTURE);
  $is_color = false;
  $output = '';
  $base = 'base';

  // Iterate over all parts
  foreach ($style as $chunk) {
    if ($is_color) {
      $chunk = drupal_strtolower($chunk);
      // Check if this is one of the colors in the default palette
      if ($key = array_search($chunk, $default)) {
        $chunk = $conversion[$key];
      }
      // Not a pre-set color. Extrapolate from the base.
      else {
        $chunk = _color_shift($palette[$base], $default[$base], $chunk, $info['blend_target']);
      }
    }
    else {
      // Determine the most suitable base color for the next color.

      // 'a' declarations. Use link.
      if (preg_match('@[^a-z0-9_-](a)[^a-z0-9_-][^/{]*{[^{]+$@i', $chunk)) {
        $base = 'link';
      }
      // 'color:' styles. Use text.
      else if (preg_match('/(?<!-)color[^{:]*:[^{#]*$/i', $chunk)) {
        $base = 'text';
      }
      // Reset back to base.
      else {
        $base = 'base';
      }
    }
    $output .= $chunk;
    $is_color = !$is_color;
  }
  // Append fixed colors segment
  $output .= $fixed;

  // Replace paths to images
  foreach ($paths['map'] as $before => $after) {
    $output = str_replace($before, $after, $output);
  }

  // Write new stylesheet
  $file = fopen($paths['stylesheet'], 'w+');
  fwrite($file, $output);
  fclose($file);
  $paths['files'][] = $paths['stylesheet'];
}

/**
 * Helper function for _color_rewrite_stylesheet.
 */
function _color_import_stylesheet($matches) {
  return preg_replace('/url\(([\'"]?)(?![a-z]+:)/i', 'url(\1'. dirname($matches[1]) .'/', file_get_contents($matches[1]));
}

/**
 * Render images that match a given palette.
 */
function _color_render_images($theme, &$info, &$paths, $palette) {

  // Prepare template image
  $source = $paths['source'] .'/'. $info['base_image'];
  $source = imagecreatefrompng($source);

  // Prepare target buffer
  $width = imagesx($source);
  $height = imagesy($source);
  $target = imagecreatetruecolor($width, $height);
  imagealphablending($target, true);

  // Fill regions of solid color.
  foreach ($info['fill'] as $color => $fill) {
    imagefilledrectangle($target, $fill[0], $fill[1], $fill[0] + $fill[2], $fill[1] + $fill[3], _color_gd($target, $palette[$color]));
  }

  // Render gradient
  for ($y = 0; $y < $info['gradient'][3]; ++$y) {
    $color = _color_blend($target, $palette['top'], $palette['bottom'], $y / ($info['gradient'][3] - 1));
    imagefilledrectangle($target, $info['gradient'][0], $info['gradient'][1] + $y, $info['gradient'][2], $info['gradient'][1] + $y + 1, $color);
  }

  // Blend over template
  imagecopy($target, $source, 0, 0, 0, 0, $width, $height);

  // Cut out slices
  foreach ($info['slices'] as $file => $coord) {
    list($x, $y, $width, $height) = $coord;
    $base = basename($file);
    $image = $paths['target'] . $base;

    // Cut out slice
    if ($file == 'screenshot.png') {
      $slice = imagecreatetruecolor(150, 90);
      imagecopyresampled($slice, $target, 0, 0, $x, $y, 150, 90, $width, $height);
      variable_set('color_'. $theme .'_screenshot', $image);
    }
    else {
      $slice = imagecreatetruecolor($width, $height);
      imagecopy($slice, $target, 0, 0, $x, $y, $width, $height);
    }

    // Save image
    imagepng($slice, $image);
    imagedestroy($slice);
    $paths['files'][] = $image;

    // Build before/after map of image paths.
    $paths['map'][$file] = $base;
  }

  // Clean up
  imagedestroy($source);
  imagedestroy($target);
}

/**
 * Shift a given color, using a reference pair and a target blend color.
 *
 * Note: this function is significantly different from the JS version, as it
 * is written to match the blended images perfectly.
 *
 * Constraint: if (ref2 == target + (ref1 - target) * delta) for some fraction delta
 *              then (return == target + (given - target) * delta)
 *
 * Loose constraint: Preserve relative positions in saturation and luminance
 *                   space.
 */
function _color_shift($given, $ref1, $ref2, $target) {

  // We assume that ref2 is a blend of ref1 and target and find
  // delta based on the length of the difference vectors:

  // delta = 1 - |ref2 - ref1| / |white - ref1|
  $target = _color_unpack($target, true);
  $ref1 = _color_unpack($ref1, true);
  $ref2 = _color_unpack($ref2, true);
  for ($i = 0; $i < 3; ++$i) {
    $numerator += ($ref2[$i] - $ref1[$i]) * ($ref2[$i] - $ref1[$i]);
    $denominator += ($target[$i] - $ref1[$i]) * ($target[$i] - $ref1[$i]);
  }
  $delta = ($denominator > 0) ? (1 - sqrt($numerator / $denominator)) : 0;

  // Calculate the color that ref2 would be if the assumption was true.
  for ($i = 0; $i < 3; ++$i) {
    $ref3[$i] = $target[$i] + ($ref1[$i] - $target[$i]) * $delta;
  }

  // If the assumption is not true, there is a difference between ref2 and ref3.
  // We measure this in HSL space. Notation: x' = hsl(x).
  $ref2 = _color_rgb2hsl($ref2);
  $ref3 = _color_rgb2hsl($ref3);
  for ($i = 0; $i < 3; ++$i) {
    $shift[$i] = $ref2[$i] - $ref3[$i];
  }

  // Take the given color, and blend it towards the target.
  $given = _color_unpack($given, true);
  for ($i = 0; $i < 3; ++$i) {
    $result[$i] = $target[$i] + ($given[$i] - $target[$i]) * $delta;
  }

  // Finally, we apply the extra shift in HSL space.
  // Note: if ref2 is a pure blend of ref1 and target, then |shift| = 0.
  $result = _color_rgb2hsl($result);
  for ($i = 0; $i < 3; ++$i) {
    $result[$i] = min(1, max(0, $result[$i] + $shift[$i]));
  }
  $result = _color_hsl2rgb($result);

  // Return hex color.
  return _color_pack($result, true);
}

/**
 * Convert a hex triplet into a GD color.
 */
function _color_gd($img, $hex) {
  $c = array_merge(array($img), _color_unpack($hex));
  return call_user_func_array('imagecolorallocate', $c);
}

/**
 * Blend two hex colors and return the GD color.
 */
function _color_blend($img, $hex1, $hex2, $alpha) {
  $in1 = _color_unpack($hex1);
  $in2 = _color_unpack($hex2);
  $out = array($img);
  for ($i = 0; $i < 3; ++$i) {
    $out[] = $in1[$i] + ($in2[$i] - $in1[$i]) * $alpha;
  }
  return call_user_func_array('imagecolorallocate', $out);
}

/**
 * Convert a hex color into an RGB triplet.
 */
function _color_unpack($hex, $normalize = false) {
  if (strlen($hex) == 4) {
    $hex = $hex[1] . $hex[1] . $hex[2] . $hex[2] . $hex[3] . $hex[3];
  }
  $c = hexdec($hex);
  for ($i = 16; $i >= 0; $i -= 8) {
    $out[] = (($c >> $i) & 0xFF) / ($normalize ? 255 : 1);
  }
  return $out;
}

/**
 * Convert an RGB triplet to a hex color.
 */
function _color_pack($rgb, $normalize = false) {
  foreach ($rgb as $k => $v) {
    $out |= (($v * ($normalize ? 255 : 1)) << (16 - $k * 8));
  }
  return '#'. str_pad(dechex($out), 6, 0, STR_PAD_LEFT);
}

/**
 * Convert a HSL triplet into RGB
 */
function _color_hsl2rgb($hsl) {
  $h = $hsl[0];
  $s = $hsl[1];
  $l = $hsl[2];
  $m2 = ($l <= 0.5) ? $l * ($s + 1) : $l + $s - $l*$s;
  $m1 = $l * 2 - $m2;
  return array(_color_hue2rgb($m1, $m2, $h + 0.33333),
               _color_hue2rgb($m1, $m2, $h),
               _color_hue2rgb($m1, $m2, $h - 0.33333));
}

/**
 * Helper function for _color_hsl2rgb().
 */
function _color_hue2rgb($m1, $m2, $h) {
  $h = ($h < 0) ? $h + 1 : (($h > 1) ? $h - 1 : $h);
  if ($h * 6 < 1) return $m1 + ($m2 - $m1) * $h * 6;
  if ($h * 2 < 1) return $m2;
  if ($h * 3 < 2) return $m1 + ($m2 - $m1) * (0.66666 - $h) * 6;
  return $m1;
}

/**
 * Convert an RGB triplet to HSL.
 */
function _color_rgb2hsl($rgb) {
  $r = $rgb[0];
  $g = $rgb[1];
  $b = $rgb[2];
  $min = min($r, min($g, $b));
  $max = max($r, max($g, $b));
  $delta = $max - $min;
  $l = ($min + $max) / 2;
  $s = 0;
  if ($l > 0 && $l < 1) {
    $s = $delta / ($l < 0.5 ? (2 * $l) : (2 - 2 * $l));
  }
  $h = 0;
  if ($delta > 0) {
    if ($max == $r && $max != $g) $h += ($g - $b) / $delta;
    if ($max == $g && $max != $b) $h += (2 + ($b - $r) / $delta);
    if ($max == $b && $max != $r) $h += (4 + ($r - $g) / $delta);
    $h /= 6;
  }
  return array($h, $s, $l);
}