<?php
/*
Plugin Name: Update Blocker
Plugin URI: https://github.com/Rarst/update-blocker
Description: Lightweight generic blocker of updates from official WordPress repositories
Author: Andrey "Rarst" Savchenko
Author URI: http://www.rarst.net/
License: MIT

Copyright (c) 2014 Andrey "Rarst" Savchenko

Permission is hereby granted, free of charge, to any person obtaining a copy of this
software and associated documentation files (the "Software"), to deal in the Software
without restriction, including without limitation the rights to use, copy, modify, merge,
publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies
or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
*/

namespace Rarst\Update_Blocker;

global $update_blocker;

$update_blocker = new Plugin( array(
	'all'     => false,
	'files'   => array( '.git', '.svn', '.hg' ),
	'plugins' => array( 'update-blocker/update-blocker.php' ),
	'themes'  => array(),
	'core'    => false,
) );

/**
 * Main and only plugin's class.
 */
class Plugin {

	/** @var object $blocked */
	public $blocked;

	/** @var object|boolean $api */
	public $api;

	/**
	 * @param array $blocked Configuration to use.
	 */
	public function __construct( $blocked = array() ) {
		register_activation_hook( __FILE__, array( $this, 'delete_update_transients' ) );
		register_deactivation_hook( __FILE__, array( $this, 'delete_update_transients' ) );

		$defaults      = array( 'all' => false, 'core' => false ) + array_fill_keys( array( 'files', 'plugins', 'themes' ), array() );
		$this->blocked = array_merge( $defaults, $blocked );

		add_action( 'init', array( $this, 'init' ) );
	}

	/**
	 * Init actions.
	 */
	public function init() {
		$this->blocked = (object) apply_filters( 'update_blocker_blocked', $this->blocked );

		if ( $this->blocked->all ) {
			add_filter( 'pre_http_request', array( $this, 'pre_http_request' ), 10, 3 );
		} else {
			add_filter( 'http_request_args', array( $this, 'http_request_args' ), 10, 2 );
		}

		if ( $this->blocked->all || $this->blocked->core ) {
			add_filter( 'pre_site_transient_update_core', array( $this, 'return_empty_core_update' ) );
		}
	}

	/**
	 * Delete update transients for plugins and themes.
	 *
	 * Performed on activation/deactivation to reset state.
	 */
	public function delete_update_transients() {
		delete_site_transient( 'update_plugins' );
		delete_site_transient( 'update_themes' );
	}

	/**
	 * Block HTTP requests to plugin/theme API endpoints.
	 *
	 * Used for complete updates block.
	 *
	 * @param boolean $false        Pass through kill request booleans.
	 * @param array   $request_args Request arguments.
	 * @param string  $url          Request URL.
	 *
	 * @return boolean|null
	 */
	public function pre_http_request( $false, $request_args, $url ) {
		$api = $this->get_api( $url );

		return empty( $api ) ? $false : null;
	}

	/**
	 * Filter blocked plugins and themes out of update request.
	 *
	 * @param array  $request_args Request arguments.
	 * @param string $url          Request URL.
	 *
	 * @return array
	 */
	public function http_request_args( $request_args, $url ) {

		$this->api = $this->get_api( $url );

		if ( empty( $this->api ) ) {
			return $request_args;
		}

		$data = $this->decode( $request_args['body'][ $this->api->type ] );

		if ( $this->api->is_plugin ) {
			$data = $this->filter_plugins( $data );
		} elseif ( $this->api->is_theme ) {
			$data = $this->filter_themes( $data );
		}

		$data = apply_filters( 'update_blocker_' . $this->api->type, $data );

		$request_args['body'][ $this->api->type ] = $this->encode( $data );

		return $request_args;
	}

	/**
	 * Determine API context for a given endpoint URL.
	 *
	 * @param string $url API URL.
	 *
	 * @return object|boolean
	 */
	public function get_api( $url ) {
		/* @see https://github.com/cftp/external-update-api/blob/master/external-update-api/euapi.php#L45 */
		static $regex = '#://api\.wordpress\.org/(?P<type>plugins|themes)/update-check/(?P<version>[0-9.]+)/#';
		$match = preg_match( $regex, $url, $api );

		if ( $match ) {
			$api['is_serial'] = ( 1.0 == (float) $api['version'] );
			$api['is_plugin'] = ( 'plugins' === $api['type'] );
			$api['is_theme']  = ( 'themes' === $api['type'] );

			return (object) $api;
		}

		return false;
	}

	/**
	 * Decode API request data, conditionally on API version.
	 *
	 * @param string $data Serialized data or JSON.
	 *
	 * @return array
	 */
	public function decode( $data ) {
		return $this->api->is_serial ? (array) unserialize( $data ) : json_decode( $data, true );
	}

	/**
	 * Encode API request data, conditionally on API version.
	 *
	 * @param array $data Data array to encode.
	 *
	 * @return string Serialized or JSON.
	 */
	public function encode( $data ) {
		if ( $this->api->is_serial ) {
			return serialize( $this->api->is_plugin ? (object) $data : $data );
		}

		return json_encode( $data );
	}

	/**
	 * Filter disabled plugins out of data set.
	 *
	 * @param array $data Data set.
	 *
	 * @return array
	 */
	public function filter_plugins( $data ) {

		foreach ( $data['plugins'] as $file => $plugin ) {
			$path = trailingslashit( WP_PLUGIN_DIR . '/' . dirname( $file ) ); // TODO files without dir?

			if ( in_array( $file, $this->blocked->plugins, true ) || $this->has_blocked_file( $path ) ) {
				unset( $data['plugins'][ $file ] );
				unset( $data['active'][ array_search( $file, $data['active'] ) ] );
			}
		}

		return $data;
	}

	/**
	 * Filter disabled themes out of data set.
	 *
	 * @param array $data Data set.
	 *
	 * @return array
	 */
	public function filter_themes( $data ) {

		foreach ( $data['themes'] as $slug => $theme ) {

			$path = trailingslashit( wp_get_theme( $slug )->get_stylesheet_directory() );

			if ( in_array( $slug, $this->blocked->themes, true ) || $this->has_blocked_file( $path ) ) {
				unset( $data['themes'][ $slug ] );
			}
		}

		return $data;
	}

	/**
	 * Determine if path location has any of blocked files from configuration.
	 *
	 * @param string $path Filesystem directory path.
	 *
	 * @return bool
	 */
	public function has_blocked_file( $path ) {

		foreach ( $this->blocked->files as $file ) {
			if ( file_exists( $path . $file ) ) {
				return true;
			}
		}

		return false;
	}

	/**
	 * Returns faked empty results to short circuit core update check.
	 *
	 * @return object
	 */
	public function return_empty_core_update() {

		global $wp_version;

		return (object) array(
			'updates'         => array(),
			'version_checked' => $wp_version,
			'last_checked'    => time(),
		);
	}
}