<?php

/**
 * A (kind of) portable file, which allows me to add some extra handling to updates for premium "daughters"
 * of freemium (mother) plugins.
 *
 * Basically, what this class does is make sure that, if automatic updates seem to be failing, the user is
 * informed (in a non-intrusive manner, i.e. the Plugins screen) of the fact that an update is indeed
 * available and where/how to download/install it manually.
 *
 * @package Daan/Updates
 */
class CAOS_Admin_Updates {
	const TRANSIENT_LABEL_APPENDIX = '_addons_latest_available_versions';

	/** @var string $plugin_text_domain */
	private $plugin_text_domain = '';

	/** @var string $plugin_text_domain */
	private $transient_label = '';

	/** @var array $premium_plugins */
	private $premium_plugins = [];

	/**
	 * Build hooks.
	 *
	 * @return void
	 */
	public function __construct( $premium_plugins, $plugin_text_domain, $transient_label ) {
		$this->premium_plugins    = $premium_plugins;
		$this->plugin_text_domain = $plugin_text_domain;
		$this->transient_label    = $transient_label;

		$this->init();
	}

	/**
	 * Action & Filter hooks.
	 *
	 * @return void
	 */
	private function init() {
		add_filter( 'all_plugins', [ $this, 'maybe_display_premium_update_notice' ] );
		add_filter( 'wp_get_update_data', [ $this, 'maybe_add_update_count' ], 10, 1 );
		add_filter( 'site_transient_update_plugins', [ $this, 'maybe_add_to_update_list' ] );
		add_filter( 'site_transient_update_plugins', [ $this, 'force_update' ], PHP_INT_MAX );
	}

	/**
	 * Addresses a possible bug introduced after @see https://core.trac.wordpress.org/ticket/61055 was introduced.
	 *
	 * Goes through the list of entered premium plugins this plugin is the parent of and removes them from the "checked" array, to force a check for updates.
	 *
	 * @param $transient
	 *
	 * @return mixed
	 */
	public function force_update( $transient ) {
		foreach ( $this->premium_plugins as $plugin ) {
			$basename = $plugin[ 'basename' ];

			if ( is_object( $transient ) && isset( $transient->checked[ $basename ] ) ) {
				unset( $transient->checked[ $basename ] );
			}
		}

		return $transient;
	}

	/**
	 * This function checks if:
	 * - Premium plugin is installed,
	 * - And if so, if an update is already available for it.
	 * - And if not, if the current version is lower than the latest available version.
	 * - And if so, display a custom notice with instructions to download the update manually.
	 *
	 * @param mixed $installed_plugins
	 *
	 * @return mixed
	 */
	public function maybe_display_premium_update_notice( $installed_plugins ) {
		$plugin_slugs = array_keys( $installed_plugins );

		foreach ( $this->premium_plugins as $id => $premium_plugin ) {
			if ( ! in_array( $premium_plugin[ 'basename' ], $plugin_slugs ) ) {
				continue;
			}

			if ( $this->update_already_displayed( $premium_plugin[ 'basename' ] ) ) {
				continue;
			}

			$latest_version  = $this->get_latest_version( $id, $premium_plugin[ 'transient_label' ] );
			$current_version = get_plugin_data( WP_PLUGIN_DIR . '/' . $premium_plugin[ 'basename' ] )[ 'Version' ] ?? '';

			if ( version_compare( $current_version, $latest_version, '<' ) ) {
				$installed_plugins[ $premium_plugin[ 'basename' ] ][ 'update' ] = true;

				add_action( 'after_plugin_row_' . $premium_plugin[ 'basename' ], [ $this, 'display_premium_update_notice' ], 10, 2 );
			}
		}

		return $installed_plugins;
	}

	/**
	 * Checks if there's already an update available for the premium plugin in the Plugins screen.
	 *
	 * @return bool
	 */
	private function update_already_displayed( $basename ) {
		$available_updates = $this->get_available_updates();

		if ( ! is_object( $available_updates ) || ! isset( $available_updates->response ) || ! is_array( $available_updates->response ) ) {
			return false;
		}

		$plugin_slugs = array_keys( $available_updates->response );

		return in_array( $basename, $plugin_slugs ) && ! empty( $available_updates->response[ $basename ]->new_version );
	}

	/**
	 * Fetch available updates from database.
	 *
	 * @return mixed
	 */
	private function get_available_updates() {
		static $available_updates;

		if ( $available_updates === null ) {
			$available_updates = get_site_transient( 'update_plugins' );
		}

		return $available_updates;
	}

	/**
	 * Gets the latest available version of the current premium plugin.
	 */
	private function get_latest_version( $id ) {
		static $latest_versions;

		/**
		 * This prevents duplicate DB reads.
		 */
		if ( $latest_versions === null ) {
			$latest_versions = get_transient( $this->transient_label . self::TRANSIENT_LABEL_APPENDIX );
		}

		/**
		 * If the transient doesn't exist, is expired or has no value, the return value will be false.
		 */
		if ( $latest_versions === false ) {
			$latest_versions = [];
		}

		$latest_version = $latest_versions[ $id ] ?? '';

		/**
		 * If $latest_versions is an empty string, that probably means something went wrong before. So,
		 * we should try and refresh it. If $latest_versions is false, then the transient doesn't exist.
		 */
		if ( $latest_version === '' ) {
			$response       = wp_remote_get( 'https://daan.dev/?edd_action=get_version&item_id=' . $id );
			$latest_version = json_decode( wp_remote_retrieve_body( $response ) )->new_version ?? '';

			/**
			 * Don't write transient if request failed for some reason.
			 */
			if ( empty( $latest_version ) ) {
				return '';
			}

			$latest_versions[ $id ] = $latest_version;

			set_transient( $this->transient_label . self::TRANSIENT_LABEL_APPENDIX, $latest_versions, DAY_IN_SECONDS );
		}

		return $latest_version;
	}

	/**
	 * Display a notice if current version of premium plugin is outdated, but updates can't be retrieved.
	 *
	 * @action after_plugin_row_{plugin_basename}
	 *
	 * @param mixed $file
	 * @param mixed $plugin_data
	 * @param mixed $status
	 *
	 * @return void
	 */
	public function display_premium_update_notice( $file, $plugin_data ) {
		$slug   = explode( '/', $file )[ 0 ] ?? '';
		$label  = $plugin_data[ 'Name' ] ?? $plugin_data[ 'name' ] ?? 'this plugin';
		$notice = sprintf(
			__(
				'An update for %1$s is available, but we\'re having trouble retrieving it. Download it from <a href="%2$s" target="_blank">your account area</a> and install it manually. <a href="%3$s" target="_blank">Need help</a>?',
				$this->plugin_text_domain
			),
			$label,
			'https://daan.dev/account/files/',
			'https://daan.dev/docs/pre-sales/download-files/'
		);

		/**
		 * This snippet of JS either overwrites the contents of the update message.
		 */ ?>
        <script>
            window.addEventListener('DOMContentLoaded', function () {
                var row = document.getElementById('<?php echo esc_attr( $slug ); ?>-update');
                var div = '';

                if (row !== null) {
                    div = row.getElementsByClassName('notice-warning');
                }

                if (div instanceof HTMLCollection && "0" in div) {
                    div[0].getElementsByTagName('p')[0].innerHTML = "<?php echo wp_kses( $notice, 'post' ); ?>";
                }
            })
        </script>
		<?php
	}

	/**
	 * This function check if:
	 * - Premium plugin is installed,
	 * - And if so, if an update is already fetched and displayed by WP itself.
	 * - And if so, if the currently installed version is lower than the latest available version,
	 * - And if so, adds 1 to the little update nag next to "Plugins" in the sidebar to attract
	 *   attention to the fact that updates seem to be failing.
	 *
	 * @param mixed $update_data
	 * @param mixed $plugins
	 *
	 * @return mixed
	 *
	 * @throws InvalidArgument
	 */
	public function maybe_add_update_count( $update_data ) {
		// phpcs:ignore
		if ( isset( $_GET[ 'plugin_status' ] ) && $_GET[ 'plugin_status' ] === 'upgrade' ) {
			return $update_data;
		}

		foreach ( $this->premium_plugins as $id => $plugin ) {
			if ( ! is_plugin_active( WP_PLUGIN_DIR . '/' . $plugin[ 'basename' ] ) ) {
				continue;
			}

			if ( $this->update_already_displayed( $plugin[ 'basename' ] ) ) {
				continue;
			}

			$latest_version  = $this->get_latest_version( $id, $plugin[ 'transient_label' ] );
			$plugin_data     = get_plugin_data( WP_PLUGIN_DIR . '/' . $plugin[ 'basename' ] );
			$current_version = $plugin_data[ 'Version' ] ?? '';

			if ( version_compare( $current_version, $latest_version, '<' ) ) {
				++ $update_data[ 'counts' ][ 'plugins' ];
			}
		}

		return $update_data;
	}

	/**
	 * Run a few checks before adding the plugin to the list of updates.
	 *
	 * @param mixed $transient
	 *
	 * @return mixed
	 */
	public function maybe_add_to_update_list( $transient ) {
		global $pagenow;

		/**
		 * Don't do anything if we're on the Dashboard > Updates page.
		 */
		if ( $pagenow === 'update-core.php' ) {
			return $transient;
		}

		if ( $transient === false ) {
			return $transient;
		}

		foreach ( $this->premium_plugins as $id => $plugin ) {
			if ( ! is_plugin_active( $plugin[ 'basename' ] ) ) {
				continue;
			}

			$latest_version  = $this->get_latest_version( $id, $plugin[ 'transient_label' ] );
			$plugin_data     = get_plugin_data( WP_PLUGIN_DIR . '/' . $plugin[ 'basename' ] );
			$current_version = $plugin_data[ 'Version' ] ?? '';

			// Due to stored, non-expired transients, it might be possible that the latest version is lower than the current version.
			if ( version_compare( $current_version, $latest_version, '>=' ) ) {
				continue;
			}

			$plugin_file = $plugin[ 'basename' ];

			// If an update is already displayed, there's no need for us to recreate this object.
			if ( is_object( $transient ) && isset( $transient->response ) && ! isset( $transient->response[ $plugin_file ] ) ) {
				$transient->response[ $plugin_file ] = (object) [
					'slug'        => explode( '/', $plugin_file )[ 0 ],
					'plugin'      => $plugin_file,
					'new_version' => '',
				];
			}
		}

		return $transient;
	}
}