private static $dependencies = array();

private static $provides = array();

private static $active_plugins;

private static $deactivate_cascade;

private static $deactivate_conflicting;

function extra_plugin_headers( $headers ) {

$headers['Provides'] = 'Provides';

$headers['Depends'] = 'Depends';

return $headers;

}

function init() {

$all_plugins = get_plugins();

$plugins_by_name = array();

foreach ( $all_plugins as $plugin => $plugin_data )

$plugins_by_name[ $plugin_data['Name'] ] = $plugin;

foreach ( $all_plugins as $plugin => $plugin_data ) {

self::$provides[ $plugin ] = self::parse_field( $plugin_data['Provides'] );

self::$provides[ $plugin ][] = $plugin;

$deps = array();

foreach ( self::parse_field( $plugin_data['Depends'] ) as $dep ) {

if ( isset( $plugins_by_name[ $dep ] ) )

$dep = $plugins_by_name[ $dep ];

$deps[] = $dep;

}

self::$dependencies[ $plugin ] = $deps;

}

}

private function parse_field( $str ) {

return array_filter( preg_split( '/,\s*/', $str ) );

}

/**

* Get a list of real or virtual dependencies for a plugin

*

* @param string $plugin_id A plugin basename

* @return array List of dependencies

*/

public function get_dependencies( $plugin_id ) {

return self::$dependencies[ $plugin_id ];

}

/**

* Get a list of dependencies provided by a certain plugin

*

* @param string $plugin_id A plugin basename

* @return array List of dependencies

*/

public function get_provided( $plugin_id ) {

return self::$provides[ $plugin_id ];

}

/**

* Get a list of plugins that provide a certain dependency

*

* @param string $dep Real or virtual dependency

* @return array List of plugins

*/

public function get_providers( $dep ) {

$plugin_ids = array();

if ( isset( self::$provides[ $dep ] ) ) {

$plugin_ids = array( $dep );

} else {

// virtual dependency

foreach ( self::$provides as $plugin => $provides ) {

if ( in_array( $dep, $provides ) ) {

$plugin_ids[] = $plugin;

}

}

}

return $plugin_ids;

}

/**

* Deactivate plugins that would provide the same dependencies as the ones in the list

*

* @param array $plugin_ids A list of plugin basenames

* @return array List of deactivated plugins

*/

public function deactivate_conflicting( $to_activate ) {

$deps = array();

foreach ( $to_activate as $plugin_id ) {

$deps = array_merge( $deps, self::get_provided( $plugin_id ) );

}

$conflicting = array();

$to_check = array_diff( get_option( 'active_plugins', array() ), $to_activate ); // precaution

foreach ( $to_check as $active_plugin ) {

$common = array_intersect( $deps, self::get_provided( $active_plugin ) );

if ( !empty( $common ) )

$conflicting[] = $active_plugin;

}

// TODO: don't deactivate plugins that would still have all dependencies satisfied

$deactivated = self::deactivate_cascade( $conflicting );

deactivate_plugins( $conflicting );

return array_merge( $conflicting, $deactivated );

}

/**

* Deactivate plugins that would have unmet dependencies

*

* @param array $plugin_ids A list of plugin basenames

* @return array List of deactivated plugins

*/

public function deactivate_cascade( $to_deactivate ) {

if ( empty( $to_deactivate ) )

return array();

self::$active_plugins = get_option( 'active_plugins', array() );

if ( is_multisite() )

self::$active_plugins = array_merge( self::$active_plugins, get_site_option( 'active_sitewide_plugins', array() ) );

self::$deactivate_cascade = array();

self::_cascade( $to_deactivate );

return self::$deactivate_cascade;

}

private function _cascade( $to_deactivate ) {

$to_deactivate_deps = array();

foreach ( $to_deactivate as $plugin_id )

$to_deactivate_deps = array_merge( $to_deactivate_deps, self::get_provided( $plugin_id ) );

$found = array();

foreach ( self::$active_plugins as $dep ) {

$matching_deps = array_intersect( $to_deactivate_deps, self::get_dependencies( $dep ) );

if ( !empty( $matching_deps ) )

$found[] = $dep;

}

$found = array_diff( $found, self::$deactivate_cascade ); // prevent endless loop

if ( empty( $found ) )

return;

self::$deactivate_cascade = array_merge( self::$deactivate_cascade, $found );

self::_cascade( $found );

deactivate_plugins( $found );

}

private static $msg;

function init() {

add_action( 'admin_notices', array( __CLASS__, 'admin_notices' ) );

add_action( 'admin_print_styles', array( __CLASS__, 'admin_print_styles' ) );

add_action( 'admin_print_footer_scripts', array( __CLASS__, 'footer_script' ), 20 );

add_filter( 'plugin_action_links', array( __CLASS__, 'plugin_action_links' ), 10, 4 );

Plugin_Dependencies::init();

load_plugin_textdomain( 'plugin-dependencies', '', dirname( plugin_basename( __FILE__ ) ) . '/lang' );

self::$msg = array(

array( 'deactivate', 'cascade', __( 'The following plugins have also been deactivated:', 'plugin-dependencies' ) ),

array( 'activate', 'conflicting', __( 'The following plugins have been deactivated due to dependency conflicts:', 'plugin-dependencies' ) ),

);

if ( !isset( $_REQUEST['action'] ) )

return;

foreach ( self::$msg as $args ) {

list( $action, $type ) = $args;

if ( $action == $_REQUEST['action'] ) {

$deactivated = call_user_func( array( 'Plugin_Dependencies', "deactivate_$type" ), (array) $_REQUEST['plugin'] );

set_transient( "pd_deactivate_$type", $deactivated );

}

}

}

function admin_notices() {

foreach ( self::$msg as $args ) {

list( $action, $type, $text ) = $args;

if ( !isset( $_REQUEST[ $action ] ) )

continue;

$deactivated = get_transient( "pd_deactivate_$type" );

delete_transient( "pd_deactivate_$type" );

if ( empty( $deactivated ) )

continue;

echo

html( 'div', array( 'class' => 'updated' ),

html( 'p', $text, self::generate_dep_list( $deactivated ) )

);

}

}

function admin_print_styles() {

?>

<style type="text/css">

.dep-list li { list-style: disc inside none }

span.deps li.unsatisfied { color: red }

span.deps li.unsatisfied_network { color: orange }

span.deps li.satisfied { color: green }

</style>

<?php

}

function footer_script() {

$all_plugins = get_plugins();

$hash = array();

foreach ( $all_plugins as $file => $data ) {

$name = isset( $data['Name'] ) ? $data['Name'] : $file;

$hash[ $name ] = sanitize_title( $name );

}

?>

<script type="text/javascript">

jQuery(function($) {

var hash = <?php echo json_encode( $hash ); ?>

$('table.widefat tbody tr').not('.second').each(function() {

var $self = $(this), title = $self.find('.plugin-title').text();

$self.attr('id', hash[title]);

});

});

</script>

<?php

}

function plugin_action_links( $actions, $plugin_file, $plugin_data, $context ) {

$deps = Plugin_Dependencies::get_dependencies( $plugin_file );

$active_plugins = (array) get_option( 'active_plugins', array() );

$network_active_plugins = (array) get_site_option( 'active_sitewide_plugins' );

if ( empty( $deps ) )

return $actions;

$unsatisfied = $unsatisfied_network = array();

foreach ( $deps as $dep ) {

$plugin_ids = Plugin_Dependencies::get_providers( $dep );

if ( !count( array_intersect( $active_plugins, $plugin_ids ) ) )

$unsatisfied[] = $dep;

if ( is_multisite() && !count( array_intersect( $network_active_plugins, $plugin_ids ) ) )

$unsatisfied_network[] = $dep;

}

if ( !empty( $unsatisfied ) ) {

unset( $actions['activate'] );

}

if ( !empty( $unsatisfied_network ) ) {

unset( $actions['network_activate'] );

}

$actions['deps'] = __( 'Required plugins:', 'plugin-dependencies' ) . '<br>' . self::generate_dep_list( $deps, $unsatisfied, $unsatisfied_network );

return $actions;

}

private function generate_dep_list( $deps, $unsatisfied = array(), $unsatisfied_network = array() ) {

$all_plugins = get_plugins();

$dep_list = '';

foreach ( $deps as $dep ) {

$plugin_ids = Plugin_Dependencies::get_providers( $dep );

if ( in_array( $dep, $unsatisfied ) )

$class = 'unsatisfied';

elseif ( in_array( $dep, $unsatisfied_network ) )

$class = 'unsatisfied_network';

else

$class = 'satisfied';

if ( empty( $plugin_ids ) ) {

$name = html( 'span', esc_html( $dep ) );

} else {

$list = array();

foreach ( $plugin_ids as $plugin_id ) {

$name = isset( $all_plugins[ $plugin_id ]['Name'] ) ? $all_plugins[ $plugin_id ]['Name'] : $plugin_id;

$list[] = html( 'a', array( 'href' => '#' . sanitize_title( $name ) ), $name );

}

$name = implode( ' or ', $list );

}

$dep_list .= html( 'li', compact( 'class' ), $name );

}

return html( 'ul', array( 'class' => 'dep-list' ), $dep_list );

}

$args = func_get_args();

$tag = array_shift( $args );

if ( is_array( $args[0] ) ) {

$closing = $tag;

$attributes = array_shift( $args );

foreach ( $attributes as $key => $value ) {

if ( false === $value )

continue;

if ( true === $value )

$value = $key;

$tag .= ' ' . $key . '="' . esc_attr( $value ) . '"';

}

} else {

list( $closing ) = explode( ' ', $tag, 2 );

}

if ( in_array( $closing, array( 'area', 'base', 'basefont', 'br', 'hr', 'input', 'img', 'link', 'meta' ) ) ) {

return "<{$tag} />";

}

$content = implode( '', $args );

return "<{$tag}>{$content}</{$closing}>";