<?php

/**
 * Entrypoint for the theme.
 */

namespace ReactWPScripts;

/**
 * Is this a development environment?
 *
 * @return bool
 */
function is_development()
{
  return apply_filters('reactwpscripts.is_development', WP_DEBUG);
}

/**
 * Attempt to load a file at the specified path and parse its contents as JSON.
 *
 * @param string $path The path to the JSON file to load.
 * @return array|null;
 */
function load_asset_file($path)
{
  if (!file_exists($path)) {
    return null;
  }
  $contents = file_get_contents($path);
  if (empty($contents)) {
    return null;
  }
  return json_decode($contents, true);
}

/**
 * Check a directory for a root or build asset manifest file, and attempt to
 * decode and return the asset list JSON if found.
 *
 * @param string $directory Root directory containing `src` and `build` directory.
 * @return array|null;
 */
function get_assets_list($directory)
{
  $directory = trailingslashit($directory);
  if (is_development()) {
    $dev_assets = load_asset_file($directory . 'asset-manifest.json');
		// Fall back to build directory if there is any error loading the development manifest.
    if (!empty($dev_assets)) {
      return array_values($dev_assets);
    }
  }

  $production_assets = load_asset_file($directory . 'build/asset-manifest.json');

  if (!empty($production_assets)) {
		// Prepend "build/" to all build-directory array paths.
    return array_map(
      function ($asset_path) {
        return 'build/' . $asset_path;
      },
      array_values($production_assets)
    );
  }

  return null;
}

/**
 * Infer a base web URL for a file system path.
 *
 * @param string $path Filesystem path for which to return a URL.
 * @return string|null
 */
function infer_base_url($path)
{
  $path = wp_normalize_path($path);

  $stylesheet_directory = wp_normalize_path(get_stylesheet_directory());
  if (strpos($path, $stylesheet_directory) === 0) {
    return get_theme_file_uri(substr($path, strlen($stylesheet_directory)));
  }

  $template_directory = wp_normalize_path(get_template_directory());
  if (strpos($path, $template_directory) === 0) {
    return get_theme_file_uri(substr($path, strlen($template_directory)));
  }

	// Any path not known to exist within a theme is treated as a plugin path.
  $plugin_path = get_plugin_basedir_path();
  if (strpos($path, $plugin_path) === 0) {
    return plugin_dir_url(__FILE__) . substr($path, strlen($plugin_path) + 1);
  }

  return '';
}

/**
 * Return the path of the plugin basedir.
 *
 * @return string
 */
function get_plugin_basedir_path()
{
  $plugin_dir_path = wp_normalize_path(plugin_dir_path(__FILE__));

  $plugins_dir_path = wp_normalize_path(trailingslashit(WP_PLUGIN_DIR));

  return substr($plugin_dir_path, 0, strpos($plugin_dir_path, '/', strlen($plugins_dir_path) + 1));
}

/**
 * Return web URIs or convert relative filesystem paths to absolute paths.
 *
 * @param string $asset_path A relative filesystem path or full resource URI.
 * @param string $base_url   A base URL to prepend to relative bundle URIs.
 * @return string
 */
function get_asset_uri($asset_path, $base_url)
{
  if (strpos($asset_path, '://') !== false) {
    return $asset_path;
  }

  return trailingslashit($base_url) . $asset_path;
}

/**
 * @param string $directory Root directory containing `src` and `build` directory.
 * @param array $opts {
 *     @type string $base_url Root URL containing `src` and `build` directory. Only needed for production.
 *     @type string $handle   Style/script handle. (Default is last part of directory name.)
 *     @type array  $scripts  Script dependencies.
 *     @type array  $styles   Style dependencies.
 *     @type array  $localize  {
 *        object_name => 'MY_GLOBAL',
 *        data => []
 *     }
 * }
 */
function enqueue_assets($directory, $opts = [])
{
  $defaults = [
    'base_url' => '',
    'handle' => basename($directory),
    'scripts' => [],
    'styles' => [],
    'localize' => [
      'name' => 'MY_GLOBAL',
      'data' => []
    ],
    'textDomain' => ''
  ];

  // var_dump($opts);

  $opts = wp_parse_args($opts, $defaults);

  $assets = get_assets_list($directory);

  $base_url = $opts['base_url'];
  if (empty($base_url)) {
    $base_url = infer_base_url($directory);
  }

  if (empty($assets)) {
		// TODO: This should be an error condition.
    return;
  }

	// There will be at most one JS and one CSS file in vanilla Create React App manifests.
  $has_css = false;
  foreach ($assets as $asset_path) {
    $is_js = preg_match('/\.js$/', $asset_path);
    $is_css = preg_match('/\.css$/', $asset_path);

    if (!$is_js && !$is_css) {
	  // Assets such as source maps and images are also listed; ignore these.
      continue;
    }

    if ($is_js) {
      $res = wp_enqueue_script(
        $opts['handle'],
        get_asset_uri($asset_path, $base_url),
        [],
        NULL,
        true
      );

      wp_localize_script(
        $opts['handle'],
        $opts['localize']['name'],
        $opts['localize']['data']
      );

    } elseif ($is_css) {
      $has_css = true;
      wp_enqueue_style(
        $opts['handle'],
        get_asset_uri($asset_path, $base_url),
        $opts['styles']
      );
    }
  }

	// Ensure CSS dependencies are always loaded, even when using CSS-in-JS in
	// development.
  if (!$has_css) {
    wp_register_style(
      $opts['handle'],
      null,
      $opts['styles']
    );
    wp_enqueue_style($opts['handle']);
  }
}