<?php
namespace W3TC;

/**
 * W3 PgCache plugin - administrative interface
 */

/**
 * class DbCache_Environment
 */
class DbCache_Environment {
	/**
	 * Fixes environment in each wp-admin request
	 *
	 * @param Config  $config
	 * @param bool    $force_all_checks
	 *
	 * @throws Util_Environment_Exceptions
	 */
	public function fix_on_wpadmin_request( $config, $force_all_checks ) {
		$exs = new Util_Environment_Exceptions();
		try {
			if ( $config->get_boolean( 'dbcache.enabled' ) ||
					Util_Environment::is_dbcluster() ) {
				$this->create_addin();
			} else {
				$this->delete_addin();
			}
		} catch ( Util_WpFile_FilesystemOperationException $ex ) {
			$exs->push( $ex );
		}

		if ( count( $exs->exceptions() ) > 0 )
			throw $exs;
	}

	/**
	 * Fixes environment once event occurs
	 *
	 * @throws Util_Environment_Exceptions
	 */
	public function fix_on_event( $config, $event, $old_config = null ) {
		if ( $config->get_boolean( 'dbcache.enabled' ) &&
			$config->get_string( 'dbcache.engine' ) == 'file' ) {
			if ( !wp_next_scheduled( 'w3_dbcache_cleanup' ) ) {
				wp_schedule_event( time(),
					'w3_dbcache_cleanup', 'w3_dbcache_cleanup' );
			}
		} else {
			$this->unschedule();
		}
	}

	/**
	 * Fixes environment after plugin deactivation
	 *
	 * @throws Util_Environment_Exceptions
	 * @return array
	 */
	public function fix_after_deactivation() {
		$exs = new Util_Environment_Exceptions();

		try {
			$this->delete_addin();
		} catch ( Util_WpFile_FilesystemOperationException $ex ) {
			$exs->push( $ex );
		}

		$this->unschedule();

		if ( count( $exs->exceptions() ) > 0 )
			throw $exs;
	}

	/**
	 * Returns required rules for module
	 *
	 * @var Config $config
	 * @return array
	 */
	function get_required_rules( $config ) {
		return null;
	}

	/**
	 * scheduling stuff
	 */
	private function unschedule() {
		if ( wp_next_scheduled( 'w3_dbcache_cleanup' ) ) {
			wp_clear_scheduled_hook( 'w3_dbcache_cleanup' );
		}
	}

	/**
	 * Creates add-in
	 *
	 * @throws Util_WpFile_FilesystemOperationException
	 */
	private function create_addin() {
		$src = W3TC_INSTALL_FILE_DB;
		$dst = W3TC_ADDIN_FILE_DB;


		if ( $this->db_installed() ) {
			if ( $this->is_dbcache_add_in() ) {
				$script_data = @file_get_contents( $dst );
				if ( $script_data == @file_get_contents( $src ) )
					return;
			} else if ( get_transient( 'w3tc_remove_add_in_dbcache' ) == 'yes' ) {
					// user already manually asked to remove another plugin's add in,
					// we should try to apply ours
					// (in case of missing permissions deletion could fail)
				} else if ( !$this->db_check_old_add_in() ) {


					if ( isset( $_GET['page'] ) )
						$url = 'admin.php?page=' . $_GET['page'] . '&amp;';
					else
						$url = basename( Util_Environment::remove_query_all( $_SERVER['REQUEST_URI'] ) ) . '?page=w3tc_dashboard&amp;';
					$remove_url = Util_Ui::admin_url( $url . 'w3tc_default_remove_add_in=dbcache' );
					throw new Util_WpFile_FilesystemOperationException(
						sprintf( __( 'The Database add-in file db.php is not a W3 Total Cache drop-in.
                    Remove it or disable Database Caching. %s', 'w3-total-cache' ),
							Util_Ui::button_link( __( 'Remove it for me', 'w3-total-cache' ), wp_nonce_url( $remove_url, 'w3tc' ) ) ) );
				}
		}

		Util_WpFile::copy_file( $src, $dst );
	}

	/**
	 * Deletes add-in
	 *
	 * @throws Util_WpFile_FilesystemOperationException
	 */
	private function delete_addin() {
		if ( $this->is_dbcache_add_in() )
			Util_WpFile::delete_file( W3TC_ADDIN_FILE_DB );
	}

	/**
	 * Returns true if db.php is installed
	 *
	 * @return boolean
	 */
	public function db_installed() {
		return file_exists( W3TC_ADDIN_FILE_DB );
	}

	/**
	 * Returns true if db.php is old version.
	 *
	 * @return boolean
	 */
	public function db_check_old_add_in() {
		if ( !$this->db_installed() )
			return false;

		return ( ( $script_data = @file_get_contents( W3TC_ADDIN_FILE_DB ) )
			&& strstr( $script_data, 'w3_instance' ) !== false );
	}

	/**
	 * Checks if db.php is W3TC drop in
	 *
	 * @return boolean
	 */
	public function is_dbcache_add_in() {
		if ( !$this->db_installed() )
			return false;

		return ( ( $script_data = @file_get_contents( W3TC_ADDIN_FILE_DB ) )
			&& strstr( $script_data, 'DbCache_Wpdb' ) !== false );
	}
}
