<?php declare(strict_types = 1);

namespace MailPoet\EmailEditor\Engine;

use MailPoet\EmailEditor\Engine\Renderer\Renderer;
use WP_Theme_JSON;
use WP_Theme_JSON_Resolver;

/**
 * E-mail editor works with own theme.json which defines settings for the editor and styles for the e-mail.
 * This class is responsible for accessing data defined by the theme.json.
 */
class ThemeController {
  private WP_Theme_JSON $coreTheme;
  private WP_Theme_JSON $baseTheme;

  public function __construct() {
    $this->coreTheme = WP_Theme_JSON_Resolver::get_core_data();
    $this->baseTheme = new WP_Theme_JSON((array)json_decode((string)file_get_contents(dirname(__FILE__) . '/theme.json'), true), 'default');
  }

  public function getTheme(): WP_Theme_JSON {
    $theme = new WP_Theme_JSON();
    $theme->merge($this->coreTheme);
    $theme->merge($this->baseTheme);

    if (Renderer::getTheme() !== null) {
      $theme->merge(Renderer::getTheme());
    }

    return apply_filters('mailpoet_email_editor_theme_json', $theme);
  }

  /**
   * Convert compressed format presets to valid CSS values.
   *
   * @param string $value Value to convert.
   * @param array $presets List of variable presets from theme.json
   * @return mixed Converted or original value.
   */
  private function maybeConvertPreset($value, $presets) {
    if (!is_string($value)) {
      return $value;
    }

    if (strstr($value, 'var:preset|color|')) {
        $value = str_replace('var:preset|color|', '', $value);
        $value = sprintf('var(--wp--preset--color--%s)', $value);
    }

    return preg_replace(array_keys($presets), array_values($presets), $value);
  }

  private function recursiveReplacePresets($values, $presets) {
    foreach ($values as $key => $value) {
      if (is_array($value)) {
        $values[$key] = $this->recursiveReplacePresets($value, $presets);
      } else {
        $values[$key] = self::maybeConvertPreset($value, $presets);
      }
    }
    return $values;
  }

  /**
   * Get styles for the e-mail.
   *
   * @param \WP_Post|null $post Post object.
   * @param \WP_Block_Template|null $template Template object.
   * @param bool $convertPresets Convert presets to valid CSS values.
   * @return array{
   *   spacing: array{
   *     blockGap: string,
   *     padding: array{bottom: string, left: string, right: string, top: string}
   *   },
   *   color: array{
   *     background: string
   *   },
   *   typography: array{
   *     fontFamily: string
   *   }
   * }
   */
  public function getStyles($post = null, $template = null, $convertPresets = false): array {
    $themeStyles = $this->getTheme()->get_data()['styles'];

    // Replace template styles.
    if ($template && $template->wp_id) { // phpcs:ignore Squiz.NamingConventions.ValidVariableName.MemberNotCamelCaps
      $templateTheme = (array)get_post_meta($template->wp_id, 'mailpoet_email_theme', true); // phpcs:ignore Squiz.NamingConventions.ValidVariableName.MemberNotCamelCaps
      $templateStyles = (array)($templateTheme['styles'] ?? []);
      $themeStyles = array_replace_recursive($themeStyles, $templateStyles);
    }

    // Replace preset values.
    if ($convertPresets) {
      $variables = $this->getVariablesValuesMap();
      $presets = [];

      foreach ($variables as $varName => $varValue) {
        $varPattern = '/var\(' . preg_quote($varName, '/') . '\)/i';
        $presets[$varPattern] = $varValue;
      }

      $themeStyles = $this->recursiveReplacePresets($themeStyles, $presets);
    }

    return $themeStyles;
  }

  public function getSettings(): array {
    $emailEditorThemeSettings = $this->getTheme()->get_settings();
    $siteThemeSettings = WP_Theme_JSON_Resolver::get_theme_data()->get_settings();
    $emailEditorThemeSettings['color']['palette']['theme'] = [];
    if (isset($siteThemeSettings['color']['palette']['theme'])) {
      $emailEditorThemeSettings['color']['palette']['theme'] = $siteThemeSettings['color']['palette']['theme'];
    }
    return $emailEditorThemeSettings;
  }

  public function getStylesheetFromContext($context, $options = []): string {
    return function_exists('gutenberg_style_engine_get_stylesheet_from_context') ? gutenberg_style_engine_get_stylesheet_from_context($context, $options) : wp_style_engine_get_stylesheet_from_context($context, $options);
  }

  public function getStylesheetForRendering($post = null, $template = null): string {
    $emailThemeSettings = $this->getSettings();

    $cssPresets = '';
    // Font family classes
    foreach ($emailThemeSettings['typography']['fontFamilies']['default'] as $fontFamily) {
      $cssPresets .= ".has-{$fontFamily['slug']}-font-family { font-family: {$fontFamily['fontFamily']}; } \n";
    }
    // Font size classes
    foreach ($emailThemeSettings['typography']['fontSizes']['default'] as $fontSize) {
      $cssPresets .= ".has-{$fontSize['slug']}-font-size { font-size: {$fontSize['size']}; } \n";
    }
    // Color palette classes
    $colorDefinitions = array_merge($emailThemeSettings['color']['palette']['theme'], $emailThemeSettings['color']['palette']['default']);
    foreach ($colorDefinitions as $color) {
      $cssPresets .= ".has-{$color['slug']}-color { color: {$color['color']}; } \n";
      $cssPresets .= ".has-{$color['slug']}-background-color { background-color: {$color['color']}; } \n";
      $cssPresets .= ".has-{$color['slug']}-border-color { border-color: {$color['color']}; } \n";
    }

    // Block specific styles
    $cssBlocks = '';
    $blocks = $this->getTheme()->get_styles_block_nodes();
    foreach ($blocks as $blockMetadata) {
      $cssBlocks .= $this->getTheme()->get_styles_for_block($blockMetadata);
    }

    // Element specific styles
    $elementsStyles = $this->getTheme()->get_raw_data()['styles']['elements'] ?? [];

    // Because the section styles is not a part of the output the `get_styles_block_nodes` method, we need to get it separately
    if ($template && $template->wp_id) { // phpcs:ignore Squiz.NamingConventions.ValidVariableName.MemberNotCamelCaps
      $templateTheme = (array)get_post_meta($template->wp_id, 'mailpoet_email_theme', true); // phpcs:ignore Squiz.NamingConventions.ValidVariableName.MemberNotCamelCaps
      $templateStyles = (array)($templateTheme['styles'] ?? []);
      $templateElements = $templateStyles['elements'] ?? [];
      $elementsStyles = array_replace_recursive((array)$elementsStyles, (array)$templateElements);
    }

    if ($post) {
      $postTheme = (array)get_post_meta($post->ID, 'mailpoet_email_theme', true);
      $postStyles = (array)($postTheme['styles'] ?? []);
      $postElements = $postStyles['elements'] ?? [];
      $elementsStyles = array_replace_recursive((array)$elementsStyles, (array)$postElements);
    }

    $cssElements = '';
    foreach ($elementsStyles as $key => $elementsStyle) {
      $selector = $key;

      if ($key === 'button') {
        $selector = '.wp-block-button';
        $cssElements .= wp_style_engine_get_styles($elementsStyle, ['selector' => '.wp-block-button'])['css'];
        // Add color to link element.
        $cssElements .= wp_style_engine_get_styles(['color' => ['text' => $elementsStyle['color']['text'] ?? '']], ['selector' => '.wp-block-button a'])['css'];
        continue;
      }

      switch ($key) {
        case 'heading':
          $selector = 'h1, h2, h3, h4, h5, h6';
          break;
        case 'link':
          $selector = 'a:not(.button-link)';
          break;
      }

      $cssElements .= wp_style_engine_get_styles($elementsStyle, ['selector' => $selector])['css'];
    }

    $result = $cssPresets . $cssBlocks . $cssElements;
    // Because font-size can by defined by the clamp() function that is not supported in the e-mail clients, we need to replace it to the value.
    // Regular expression to match clamp() function and capture its max value
    $pattern = '/clamp\([^,]+,\s*[^,]+,\s*([^)]+)\)/';
    // Replace clamp() with its maximum value
    $result = (string)preg_replace($pattern, '$1', $result);
    return $result;
  }

  public function translateSlugToFontSize(string $fontSize): string {
    $settings = $this->getSettings();
    foreach ($settings['typography']['fontSizes']['default'] as $fontSizeDefinition) {
      if ($fontSizeDefinition['slug'] === $fontSize) {
        return $fontSizeDefinition['size'];
      }
    }
    return $fontSize;
  }

  public function translateSlugToColor(string $colorSlug): string {
    $settings = $this->getSettings();
    $colorDefinitions = array_merge($settings['color']['palette']['theme'], $settings['color']['palette']['default']);
    foreach ($colorDefinitions as $colorDefinition) {
      if ($colorDefinition['slug'] === $colorSlug) {
        return strtolower($colorDefinition['color']);
      }
    }
    return $colorSlug;
  }

  public function getVariablesValuesMap(): array {
    $variablesCss = $this->getTheme()->get_stylesheet(['variables']);
    $map = [];
    // Regular expression to match CSS variable definitions
    $pattern = '/--(.*?):\s*(.*?);/';

    if (preg_match_all($pattern, $variablesCss, $matches, PREG_SET_ORDER)) {
      foreach ($matches as $match) {
        // '--' . $match[1] is the variable name, $match[2] is the variable value
        $map['--' . $match[1]] = $match[2];
      }
    }

    return $map;
  }
}