<?php

/**
 * Adv_Term_Fields_Locks Class
 *
 * Adds locks for taxonomy terms.
 *
 * @package Advanced_Term_Fields
 * @subpackage Adv_Term_Fields_Locks
 *
 * @since 0.1.0
 *
 */

// No direct access
if ( ! defined( 'ABSPATH' ) ) {
	header( 'Status: 403 Forbidden' );
	header( 'HTTP/1.1 403 Forbidden' );
	exit();
}


/**
 * Adds locks for taxonomy terms
 *
 * @version 1.0.0
 *
 * @since 0.1.0
 *
 */
class Adv_Term_Fields_Locks extends Advanced_Term_Fields
{

	/**
	 * Version number
	 *
	 * @since 0.1.0
	 *
	 * @var string
	 */
	protected $version = ATF_LOCKS_VERSION;


	/**
	 * Metadata database key
	 *
	 * For storing/retrieving the meta value.
	 *
	 * @since 0.1.0
	 *
	 * @var string
	 */
	public $meta_key = '_term_lock';


	/**
	 * Singular slug for meta key
	 *
	 * Used for:
	 * - localizing js files
	 * - form field views
	 *
	 * @see Adv_Term_Fields_Locks::enqueue_admin_scripts()
	 * @see Adv_Term_Fields_Locks\Views\(add|edit|qedit).php
	 *
	 * @since 0.1.2
	 *
	 * @var string
	 */
	public $meta_slug = 'term-lock';


	/**
	 * Unique singular descriptor for meta type
	 *
	 * (e.g.) "icon", "color", "thumbnail", "image", "lock".
	 *
	 * Used in localizing js files.
	 *
	 * @see Adv_Term_Fields_Locks::enqueue_admin_scripts()
	 *
	 * @since 0.1.0
	 *
	 * @var string
	 */
	public $data_type = 'lock';


	/**
	 * Flag to display custom column
	 *
	 * Determines whether or not to show the meta value in a custom column on the terms list table.
	 *
	 * @see Advanced_Term_Fields::show_custom_column()
	 *
	 * @since 0.1.0
	 *
	 * @var bool
	 */
	public $show_custom_column = false;


	/**
	 * Constructor
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @param string $file Full file path to calling plugin file
	 */
	public function __construct( $file = '' )
	{
		parent::__construct( $file );
	}


	/**
	 * Loads the class
	 *
	 * @uses Advanced_Term_Fields::show_custom_column()
	 * @uses Advanced_Term_Fields::show_custom_fields()
	 * @uses Advanced_Term_Fields::register_meta()
	 * @uses Advanced_Term_Fields::process_term_meta()
	 * @uses Advanced_Term_Fields::filter_terms_query()
	 * @uses Advanced_Term_Fields::$allowed_taxonomies
	 * @uses Adv_Term_Fields_Locks::load_admin_functions()
	 * @uses Adv_Term_Fields_Locks::show_inner_fields()
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 */
	public function init()
	{
		$this->register_meta();
		$this->load_admin_functions();
		$this->show_custom_column( $this->allowed_taxonomies );
		$this->show_custom_fields( $this->allowed_taxonomies );
		$this->process_term_meta();
		$this->filter_terms_query();
		$this->show_inner_fields();

		$this->filter_term_name();
		$this->check_table_row_actions( $this->allowed_taxonomies );
		$this->check_term_delete();
		$this->check_edit_screen();
		$this->check_term_update();
		//$this->manage_term_lock_caps();
	}



	/**
	 * Loads various admin functions
	 *
	 * - Checks for version update.
	 * - Loads js/css scripts
	 *
	 * @uses Advanced_Term_Fields::load_admin_functions()
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @return void
	 */
	public function load_admin_functions()
	{
		parent::load_admin_functions();
		add_action( 'admin_init', array( $this, 'check_for_update' ) );
	}


	/**
	 * Loads upgrade check
	 *
	 * Checks if declared plugin version  matches the version stored in the database.
	 *
	 * @uses Adv_Term_Fields_Locks::$version
	 * @uses Adv_Term_Fields_Locks::$db_version_key
	 * @uses WordPress get_option()
	 * @uses Adv_Term_Fields_Locks::upgrade_version()
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @return void
	 */
	public function check_for_update()
	{
		$db_version_key = $this->db_version_key;
		$db_version = get_option( $db_version_key );
		$plugin_version = $this->version;

		do_action( "atf_pre_{$this->meta_key}_upgrade_check", $db_version_key, $db_version );

		if( ! $db_version || version_compare( $db_version, $plugin_version, '<' ) ) {
			$this->upgrade_version( $db_version_key, $plugin_version, $db_version, $this->meta_key );
		}
	}


	/**
	 * Upgrades database record of plugin version
	 *
	 * @uses WordPress update_option()
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @param string $db_version_key The database key for the plugin version.
	 * @param string $plugin_version The most recent plugin version.
	 * @param string $db_version     The plugin version stored in the database pre upgrade.
	 * @param string $meta_key       The meta field key.
	 *
	 * @return bool $updated True if version has changed, false if not or if update failed.
	 */
	public function upgrade_version( $db_version_key, $plugin_version, $db_version = 0, $meta_key = '' )
	{
		do_action( "atf_pre_{$meta_key}_version_upgrade", $plugin_version, $db_version, $db_version_key );

		$updated = update_option( $db_version_key, $plugin_version );

		do_action( "atf_{$meta_key}_version_upgraded", $updated, $db_version_key, $plugin_version, $db_version, $meta_key );

		return $updated;
	}


	/**
	 * Sets labels for form fields
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 */
	public function set_labels()
	{
		$this->labels = array(
			'singular'	  => esc_html__( 'Lock',  'atf-locks' ),
			'plural'	  => esc_html__( 'Locks', 'atf-locks' ),
			'description' => esc_html__( 'Enable locking of this term.', 'atf-locks' )
		);
	}


	/**
	 * Loads js admin scripts
	 *
	 * Note: Only loads on edit-tags.php
	 *
	 * @uses Advanced_Term_Fields::$custom_column_name
	 * @uses Advanced_Term_Fields::$meta_key
	 * @uses Advanced_Term_Fields::$data_type
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @param string $hook The slug of the currently loaded page.
	 *
	 * @return void
	 */
	public function enqueue_admin_scripts( $hook )
	{
		wp_enqueue_script( 'atf-locks', $this->url . 'js/admin.js', array( 'jquery'), '', true );

		wp_localize_script( 'atf-locks', 'l10n_ATF_Locks', array(
			'custom_column_name' => esc_html__( $this->custom_column_name ),
			'meta_key'	         => esc_html__( $this->meta_key ),
			'meta_slug'	         => esc_html__( $this->meta_slug ),
			'data_type'	         => esc_html__( $this->data_type ),
		) );
	}


	/**
	 * Prints out CSS styles in admin head
	 *
	 * Note: Only loads on edit-tags.php
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @return void
	 */
	public function admin_head_styles()
	{
		ob_start();
		include dirname( $this->file ) . '/css/admin.css';
		$css = ob_get_contents();
		ob_end_clean();

		echo $css;
	}


	/**
	 * Displays inner form field on Add Term form
	 *
	 * @see Advanced_Term_Fields::show_custom_fields()
	 * @see Advanced_Term_Fields::add_form_field()
	 *
	 * @uses Advanced_Term_Fields::$file To include view.
	 * @uses Advanced_Term_Fields::$meta_key To populate field attributes.
	 * @uses Advanced_Term_Fields::$meta_slug To populate CSS IDs, classes.
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @param string $taxonomy Current taxonomy slug.
	 *
	 * @return void
	 */
	public function show_inner_field_add( $taxonomy = '' )
	{
		ob_start();
		include dirname( $this->file ) . '/views/inner-add-form-field.php';
		$field = ob_get_contents();
		ob_end_clean();

		echo $field;
	}


	/**
	 * Displays inner form field on Edit Term form
	 *
	 * @see Advanced_Term_Fields::show_custom_fields()
	 * @see Advanced_Term_Fields::edit_form_field()
	 *
	 * @uses Advanced_Term_Fields::$file To include view.
	 * @uses Advanced_Term_Fields::$meta_key To populate field attributes.
	 * @uses Advanced_Term_Fields::get_meta() To retrieve meta value.
	 * @uses Advanced_Term_Fields::$meta_slug To populate CSS IDs, classes.
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @param object $term Term object.
	 * @param string $taxonomy Current taxonomy slug.
	 *
	 * @return void
	 */
	public function show_inner_field_edit( $term = false, $taxonomy = '' )
	{
		ob_start();
		include dirname( $this->file ) . '/views/inner-edit-form-field.php';
		$field = ob_get_contents();
		ob_end_clean();

		echo $field;
	}


	/**
	 * Displays inner form field on Quick Edit Term form
	 *
	 * @see Advanced_Term_Fields::show_custom_fields()
	 * @see Advanced_Term_Fields::quick_edit_form_field()
	 *
	 * @uses Advanced_Term_Fields::$file To include view.
	 * @uses Advanced_Term_Fields::$meta_key To populate field attributes.
	 * @uses Advanced_Term_Fields::$meta_slug To populate CSS IDs, classes.
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @param string $column_name Name of the column to edit.
	 * @param string $screen	  The screen name.
	 * @param string $taxonomy	  Current taxonomy slug.
	 *
	 * @return void
	 */
	public function show_inner_field_qedit( $column_name = '' , $screen = '' , $taxonomy = '' ){}


	/**
	 * Creates the value of the term lock
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @return string $lock Empty if no user is detected, hash of current time|user ID if successful.
	 */
	public function create_term_lock()
	{
		$lock = '';

		if ( 0 == ( $user_id = get_current_user_id() ) ) {
			return $lock;
		}

		$now = time();
		$lock = "$now:$user_id";

		$lock = apply_filters( "atf_term_lock", $lock );

		return $lock;
	}



	/**
	 * Retrieves current taxonomy
	 *
	 * Note: Not used as of 0.1.0
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @return string $current_taxonomy The current taxonomy.
	 */
	public function get_current_taxonomy()
	{
		global $taxnow;

		$current_taxonomy = $taxnow;

		if( '' === $current_taxonomy || is_null( $current_taxonomy ) ) {
			$current_taxonomy = ( ! empty( $_REQUEST['taxonomy'] ) )? esc_attr( $_REQUEST['taxonomy'] ) : '';
		};

		if( '' === $current_taxonomy && function_exists( 'get_current_screen' ) ) {
			$current_taxonomy = get_current_screen()->taxonomy;
		};

		if( is_null( $current_taxonomy ) ) {
			$current_taxonomy = '';
		};

		return $current_taxonomy;
	}



	/**
	 * Prevents deletion of term
	 *
	 * @see Adv_Term_Fields_Locks::maybe_prevent_term_delete()
	 * @see WordPress wp_delete_term()
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @return void
	 */
	public function check_term_delete()
	{
		add_action( 'pre_delete_term', array( $this, 'maybe_prevent_term_delete' ), 99, 2 );
	}


	/**
	 * Prevents deletion of term
	 *
	 * Applies filter "atf_locks_term_delete_cap" to allow other plugins to filter the capability.
	 *
	 * @uses Adv_Term_Fields_Locks::get_prevent_msg()
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @param int    $term_id  Term ID.
	 * @param string $taxonomy Taxonomy Name.
	 *
	 * @return mixed int    $term_id If current user can delete the term or term is not locked.
	 *               object WP_Error If current user can't delete term or user is not detected.
	 *               die()  On AJAX calls: If current user can't delete term or user is not detected.
	 */
	public function maybe_prevent_term_delete( $term_id, $taxonomy )
	{
		// If no lock, return term ID
		if ( ! $lock = get_term_meta( $term_id, $this->meta_key, true ) ) {
			return $term_id;
		};

		$cap = apply_filters( "atf_locks_term_delete_cap", "manage_others_term_locks" );
		$user_can_delete = $this->_user_can( $cap, $term_id, $taxonomy, $lock );

		if ( ! $user_can_delete ) :
			if ( defined('DOING_AJAX') && DOING_AJAX ) {
				wp_die( -1 );
			} else {
				$_msg = $this->get_prevent_msg( $action = 'delete' );
				wp_die( $_msg, 403 );
			};
		endif;

		return $term_id;
	}


	/**
	 * Filters term name
	 *
	 * @see Adv_Term_Fields_Locks::term_name()
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @return void
	 */
	public function filter_term_name()
	{
		add_filter( 'term_name', array( $this, 'maybe_filter_term_name' ), 99, 2 );
	}


	/**
	 * Filters term name
	 *
	 * Appends a dashicon lock icon to the end of locked term names in Terms List Table.
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @param string $name The term name, padded if not top-level.
	 * @param object $term Term object.
	 *
	 * @return string $name The filtered term name.
	 */
	public function maybe_filter_term_name( $name = '', $term = null )
	{
		if ( ! is_object( $term ) ) {
			return $name;
		};

		$lock = get_term_meta( $term->term_id, $this->meta_key, true );

		if ( $lock ) {
			$cap = apply_filters( "atf_locks_term_manage_cap", "manage_others_term_locks" );
			$user_can_manage = $this->_user_can( $cap, $term->term_id, $term->taxonomy, $lock );

			$dashicon = ( $user_can_manage ) ? ' dashicons-unlock' : '' ;

			$name .= ' <span class="dashicons dashicons-lock'.$dashicon.'"></span>';
		};

		return $name;
	}


	/**
	 * Filters table row actions
	 *
	 * @see Adv_Term_Fields_Locks::maybe_filter_row_actions()
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @return array $allowed_taxonomies The allowed taxonomies.
	 */
	public function check_table_row_actions( $allowed_taxonomies = array() )
	{
		if ( ! empty( $allowed_taxonomies ) ) :
			foreach ( $allowed_taxonomies as $tax_name ) {
				add_filter( "{$tax_name}_row_actions", array( $this, 'maybe_filter_row_actions' ), 10, 2 );
			}
		endif;

		return $allowed_taxonomies;
	}


	/**
	 * Filters table row actions
	 *
	 * Removes edit|quick edit|delete links from table row actions if current user can't manage
	 * locked terms.
	 * Applies filter "atf_allowed_row_actions" to allow other plugins to filter the allowed actions.
	 * Applies filter "atf_locks_term_manage_cap" to allow other plugins to filter the capability.
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @param array  $actions An array of action links to be displayed. Default actions:
	 *                        array( 'edit' => 'Edit', 'inline hide-if-no-js' => 'Quick Edit',
	 *                               'delete' => 'Delete', 'view' => 'View' )
	 * @param object $term    Term object.
	 */
	public function maybe_filter_row_actions( $actions, $term )
	{
		// If no lock, return $actions
		if ( ! $lock = get_term_meta( $term->term_id, $this->meta_key, true ) ) {
			return $actions;
		}

		$allowed_actions = apply_filters( "atf_allowed_row_actions", array('view') );
		$filtered_actions = array_intersect_key( $actions, array_flip($allowed_actions) );

		$cap = apply_filters( "atf_locks_term_manage_cap", "manage_others_term_locks" );
		$user_can_action = $this->_user_can( $cap, $term->term_id, $term->taxonomy, $lock );

		if ( ! $user_can_action ) {
			return $filtered_actions;
		};

		return $actions;
	}


	/**
	 * Prevents access to Edit Tags screen
	 *
	 * @see Adv_Term_Fields_Locks::maybe_prevent_edit_screen()
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @return void
	 */
	public function check_edit_screen()
	{
		add_action ( 'load-edit-tags.php', array($this, 'maybe_prevent_edit_screen'), 10 );
	}



	/**
	 * Prevents unauthorized users from accessing the Edit Tags screen
	 *
	 * Applies filter "atf_locks_term_manage_cap" to allow other plugins to filter the capability.
	 *
	 * @uses Adv_Term_Fields_Locks::get_prevent_msg()
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @return mixed null     If term is not locked or user can access.
	 *               wp_die() If current user can't edit term or user is not detected.
	 */
	public function maybe_prevent_edit_screen()
	{
		if ( empty( $_GET['tag_ID'] ) ){
			return;
		};

		$term_id = ( ! empty( $_GET['tag_ID'] ) ) ? absint( $_GET['tag_ID'] ) : '' ;

		// If no lock, return
		if ( ! $lock = get_term_meta( $term_id, $this->meta_key, true ) ) {
			return;
		};

		$taxonomy = ( ! empty( $_GET['taxonomy'] ) ) ? esc_attr( $_GET['taxonomy'] ) : '' ;

		$cap = apply_filters( "atf_locks_term_manage_cap", "manage_others_term_locks" );
		$user_can_edit = $this->_user_can( $cap, $term_id, $taxonomy, $lock );

		if ( ! $user_can_edit ) {
			$_msg = $this->get_prevent_msg( $action = 'edit' );
			wp_die( $_msg, 403 );
		};
	}


	/**
	 * Prevents update of term
	 *
	 * @see Adv_Term_Fields_Locks::maybe_prevent_term_update()
	 * @see WordPress wp_update_term()
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @return void
	 */
	public function check_term_update()
	{
		add_action ( 'edit_terms', array( $this, 'maybe_prevent_term_update' ), 99, 2 );
	}


	/**
	 * Prevents updating of term
	 *
	 * Applies filter "atf_locks_term_update_cap" to allow other plugins to filter the capability.
	 *
	 * @uses Adv_Term_Fields_Locks::get_prevent_msg()
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @param int    $term_id  Term ID.
	 * @param string $taxonomy Taxonomy slug.
	 *
	 * @return mixed int      $term_id If current user can delete the term or term is not locked.
	 *               wp_die() If current user can't delete term or user is not detected.
	 */
	public function maybe_prevent_term_update( $term_id, $taxonomy )
	{
		// If no lock, return term ID
		if ( ! $lock = get_term_meta( $term_id, $this->meta_key, true ) ) {
			return $term_id;
		};

		$cap = apply_filters( "atf_locks_term_update_cap", "manage_others_term_locks" );
		$user_can_update = $this->_user_can( $cap, $term_id, $taxonomy, $lock );

		if ( ! $user_can_update ) :
			if ( defined('DOING_AJAX') && DOING_AJAX ) {
				$_ajax_msg = sprintf( '<span class="term-locked-err">%s</span>',
					__( 'This term is locked.', 'atf-locks' )
				);
				$_ajax_msg = apply_filters( "atf_unauthorized_term_update_msg_ajax", $_ajax_msg );
				wp_die( $_ajax_msg );
			} else {
				$_msg = $this->get_prevent_msg( $action = 'update' );
				wp_die( $_msg, 403 );
			};

		endif;

		return $term_id;
	}



	/**
	 * Displays unauthorized message
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @return string Message for user.
	 */
	public function get_prevent_msg( $action = 'manage' )
	{
		$_msg = sprintf( '<h1>%s</h1><p>%s</p>',
			__( "Locked Term", 'atf-locks' ),
			__( "One or more of the selected terms are locked.  You are not allowed to {$action}.", 'atf-locks' )
		);

		return apply_filters( "atf_unauthorized_term_{$action}_msg", $_msg );
	}



	/**
	 * Checks user authorization to manage term
	 *
	 * Checks happen in this order:
	 * - No lock: allow
	 * - No current user: prevent
	 * - Current user matches lock author: allow
	 * - Current user can manage others term locks: allow
	 * - Current user does not match lock author: prevent
	 *
	 * @uses Adv_Term_Fields_Locks::prevent_delete_msg()
	 *
	 * @access protected
	 *
	 * @since 0.1.0
	 *
	 * @param string $capability The user_cap to check against.
	 * @param int    $term_id  Term ID.
	 * @param string $taxonomy Taxonomy name.
	 * @param string $lock     The term lock hash.  Typically: "time:user_id".
	 *
	 * @return boolean True if user is authorized, false if not.
	 */

	protected function _user_can( $capability, $term_id, $taxonomy, $lock = '' )
	{
		// No lock
		if ( ! $lock ) {
			return true;
		}

		// If we can't detect the current user
		if ( 0 == ( $current_user_id = get_current_user_id() ) ) {
			return false;
		};

		// If the current user matches the term lock author
		$lock = explode( ':', $lock );
		$lock_user_id = isset( $lock[1] ) ? $lock[1] : 0;

		if ( (int) $current_user_id === (int) $lock_user_id ) {
			return true;
		}

		// If the current user can $capability
		if ( current_user_can( $capability ) ) {
			return true;
		};

		// If the current user doesn't match the term lock author
		if ( (int) $current_user_id !== (int) $lock_user_id ) {
			return false;
		};

		return;
	}


	/**
	 * Filters term lock capabilities
	 *
	 * @see Adv_Term_Fields_Locks::maybe_add_lock_cap()
	 *
	 * @access public
	 *
	 * @since 0.1.0
	 *
	 * @return void
	 */
	public function manage_term_lock_caps()
	{
		add_filter( 'atf_locks_term_delete_cap', array( $this, 'maybe_add_lock_cap' ) );
		add_filter( 'atf_locks_term_manage_cap', array( $this, 'maybe_add_lock_cap' ) );
		add_filter( 'atf_locks_term_update_cap', array( $this, 'maybe_add_lock_cap' ) );
	}
	
	
	/**
	 * Sets the capability for managing terms with term locks
	 *
	 * @since 0.1.0
	 *
	 * @param string $cap The capability being filtered.  Default is "manage_others_term_locks".
	 *
	 * @return string $cap The filtered capability.
	 */
	public function maybe_add_lock_cap( $cap )
	{
		if( is_super_admin() ) {
			return 'manage_categories';
		}
		return $cap;
	}
	
	
}