easy-settings.php

<?php
/**
 * Plugin Name: Easy Settings
 * Plugin URI: https://github.com/mrcsmcln/easy-settings
 * Description: Easily create options pages without having to use the Settings 
 * API.
 * Author: Marcus McLean
 * Version: 0.5
 * Author URI: https://www.odesk.com/users/%7E012eaf926aadbd170e
 * License: GPL2
 * 
 * @package Easy_Settings
 * @version 0.5
 */

class Easy_Settings {
	/**
	 * Whether Easy Settings will be run from a theme or a plugin.
	 * 
	 * @since Easy Settings 0.5
	 * @var string
	 */
 	// const TYPE = 'plugin';
	const TYPE = 'theme';
	
	/**
	 * The directory in which the settings will be stored. Applicable only when
	 * Easy_Settings::TYPE is 'theme'.
	 * 
	 * @since Easy Settings 0.5
	 * @var string
	 */
	const ROOT = '/easy-settings';
	
	/**
	 * The current submenu.
	 * 
	 * @since Easy Settings 0.5
	 * @var string
	 */
	public $current_submenu;
	
	/**
	 * The current submenu page.
	 * 
	 * @since Easy Settings 0.5
	 * @var string
	 */
	public $current_page;
	
	/**
	 * The current option.
	 * 
	 * @since Easy Settings 0.5
	 * @var string
	 */
	public $current_option;
	
	/**
	 * The current settings section.
	 * 
	 * @since Easy Settings 0.5
	 * @var string
	 */
	public $current_section;
	
	/**
	 * The current settings field.
	 *
	 * @since Easy Settings 0.5
	 * @var string
	 */
	public $current_field;
	
	/**
	 * The settings fields for the current option.
	 * 
	 * @since Easy Settings 0.5
	 * @var array
	 */
	public $fields;
	
	/**
	 * The errors generated by silly programming.
	 * 
	 * @since Easy Settings 0.5
	 * @var array
	 */
	public $errors;
	
	/**
	 * Easy_Settings constructor.
	 * 
	 * @since Easy Settings 0.5
	 */
	public function __construct() {
		if ( 'theme' !== self::TYPE && 'plugin' !== self::TYPE ) {
			$this->error( "<code>Easy_Settings::TYPE</code> must be either <code>'plugin'</code> or <code>'theme'</code>." );
		} else {
			add_action( 'admin_menu', array( $this, 'admin_menu' ) );
			add_action( 'admin_init', array( $this, 'admin_init' ) );
		}
	}

	/**
	 * Displays the submenu page.
	 * 
	 * @since Easy Settings 0.5
	 */
	public function submenu_page() {
		$this->current_submenu = $this->get_current_submenu();
		$this->current_page = $this->get_current_page();
		$this->current_option = "mjm_{$this->current_submenu}_$this->current_page";
		$this->fields = get_option( $this->current_option );
		$page_file = $this->get_file( "$this->current_submenu-pages/$this->current_page/index.php" );
		if ( $page_file ) {
			include $page_file;
		} else { ?>
			<div class="wrap">
				<h2><?php echo $this->format_title( $this->current_page ); ?></h2>
				<form action="options.php" method="post"><?php
					settings_fields( $this->current_option );
					do_settings_sections( 'mjm-' . $this->current_page );
					submit_button();
				?></form>
			</div>
<?php	}		
	}
	
	/**
	 * Displays the submenu page for the current submenu.
	 * 
	 * @since Easy Settings 0.5
	 */
	public function submenu_pages() {
		$default_capability = 'edit_theme_options';
		$submenu_dir = $this->get_dir( $this->current_submenu );
		switch ( $this->current_submenu ) {
			case 'dashboard-pages':
				$parent_slug = 'index.php';
				break;
			case 'posts-pages':
				$parent_slug = 'edit.php';
				$capability  = 'edit_posts';
				break;
			case 'media-pages':
				$parent_slug = 'upload.php';
				$capability  = 'upload_files';
				break;
			case 'comments-pages':
				$parent_slug = 'edit.php?post_type=page';
				$capability  = 'edit_pages';
				break;
			case 'theme-pages':
				$capability  = 'edit_theme_options';
				$parent_slug = 'themes.php';
				break;
			case 'plugins-pages':
				$parent_slug = 'plugins.php';
				$capability  = 'activate_plugins';
				break;
			case 'users-pages':
				$parent_slug = 'users.php';
				$capability  = 'promote_users';
				break;
			case 'management-pages':
				$parent_slug = 'tools.php';
				$capability  = 'manage_options';
				break;
			case 'options-pages':
				$parent_slug = 'options-general.php';
				$capability  = 'manage_options';
				break;
			case 'settings-pages': // non-standard
				$parent_slug = 'settings.php';
				$capability  = 'manage_options';
				break;
			default:
				$parent_slug = 'edit.php?post_type=' . substr( $this->current_submenu, 0, -6 );
				$capability  = 'edit_posts';
		}
		
		$default_headers = array(
			'PageTitle' => 'Page Title',
			'MenuTitle' => 'Menu Title',
			'Capability' => 'Capability',
		);
		
		foreach ( preg_grep('/^[^\.]/', scandir( $submenu_dir ) ) as &$page ) {
			$page_dir = $this->get_dir( "$this->current_submenu/$page" );
			if ( $page_dir ) {
				$page_file = $this->get_file( "$this->current_submenu/$page/index.php" );
				if ( $page_file ) {
					$headers = get_file_data( $page_file, $default_headers );
				}
				$page_title = empty( $headers['PageTitle'] )  ? $this->format_title( $page ) : $headers['PageTitle'];
				$menu_title = empty( $headers['MenuTitle'] )  ? $this->format_title( $page ) : $headers['MenuTitle'];
				$capability = empty( $headers['Capability'] ) ? $default_capability          : $headers['Capability'];
				add_submenu_page( $parent_slug, $page_title, $menu_title, $capability, "mjm-$page", array( $this, 'submenu_page' ) );
			}
		}
		unset( $page );
	}
	
	/**
	 * Scans the admin menu for submenu pages.
	 * 
	 * @since Easy Settings 0.5
	 */
	public function admin_menu() {
		$admin_dir = $this->get_dir( '' );
		if ( $admin_dir ) {
			foreach ( scandir( $admin_dir ) as &$submenu ) {
				$submenu_dir = $this->get_dir( $submenu );
				if ( $submenu_dir && '-pages' === substr( $submenu, -6 ) ) {
					$this->current_submenu = $submenu;
					$this->submenu_pages( $submenu );
				}
			}
			unset( $submenu );
		}
	}
	
	/**
	 * Displays the current settings field.
	 * 
	 * @since Easy Settings 0.5
	 * 
	 * @param string $field The current settings field.
	 */
	public function settings_field( $field ) {
		$this->current_field = $field['field'];
		$field_file = $this->get_file( "$this->current_submenu-pages/$this->current_page/$this->current_section/$this->current_field.php" );
		if ( $field_file && filesize( $field_file ) ) {
			include $field_file;
		} else { ?>
			<input type="text" id="<?php echo esc_attr( $this->current_field ); ?>" name="<?php echo esc_attr( "$this->current_option[$this->current_field]" ); ?>" value="<?php echo isset( $this->fields[ $this->current_field ] ) ? esc_attr( $this->fields[ $this->current_field ] ) : ''; ?>">
<?php	}
	}
	
	/**
	 * Displays the current settings section.
	 * 
	 * @since Easy Settings 0.5
	 * 
	 * @param string $section The current settings section.
	 */
	public function settings_section( $section ) {
		$this->current_section = $section['id'];
		$section_file = $this->get_file( "$this->current_submenu-pages/$this->current_page/$this->current_section/index.php" );
		if ( $section_file ) {
			include $section_file;
		}
	}
	
	/**
	 * Adds settings fields to the current settings section.
	 * 
	 * @since Easy Settings 0.5
	 */
	public function settings_fields() {
		$default_headers = array(
			'Title' => 'Title',
			'LabelFor' => 'Label For',
		);
		$section_dir = $this->get_dir( "$this->current_submenu/$this->current_page/$this->current_section" );
		foreach ( scandir( $section_dir ) as &$field ) {
			$field_file = $this->get_file( "$this->current_submenu/$this->current_page/$this->current_section/$field" );
			if ( $field_file && 'php' === pathinfo( $field_file, PATHINFO_EXTENSION ) && 'index.php' !== $field ) {
				$headers = get_file_data( $field_file, $default_headers );
				$id = substr( $field, 0, -4 );
				$title = empty( $headers['Title'] ) ? $this->format_title( $id ) : $headers['Title'];
				$label_for = $headers['LabelFor'];
				add_settings_field( $id, $title, array( $this, 'settings_field' ), "mjm-$this->current_page", $this->current_section, array(
					'field' => substr( $field, 0, -4 ),
					'label_for' => $headers['LabelFor'],
				) );
			}
		}
		unset( $field );
	}
	
	/**
	 * Adds settings sections to the current submenu page.
	 * 
	 * @since Easy Settings 0.5
	 */
	public function settings_sections() {
		$default_headers = array(
			'Title' => 'Title',
		);
		$page_dir = $this->get_dir( "$this->current_submenu/$this->current_page" );
		foreach ( scandir( $page_dir ) as &$section ) {
			$section_dir = $this->get_dir( "$this->current_submenu/$this->current_page/$section" );
			if ( $section_dir && '.' !== $section[0] ) {
				$this->current_section = $section;
				$section_file = $this->get_file( "$section_dir/index.php" );
				if ( $section_file ) {
					$headers = get_file_data( $section_file, $default_headers );
				}
				$title = empty( $headers['Title'] ) ? $this->format_title( $this->current_section ) : $headers['Title'];
				add_settings_section( $this->current_section, $title, array( $this, 'settings_section' ), "mjm-$this->current_page" );
				$this->settings_fields();
			}
		}
		unset( $section );
	}
	
	/**
	 * Registers settings for the current page.
	 * 
	 * @since Easy Settings 0.5
	 */
	public function admin_init() {
		$default_headers = array(
			'SanitizeCallback' => 'Sanitize Callback',
		);
		$admin_dir = $this->get_dir( '' );
		if ( $admin_dir ) {
			foreach ( scandir( $admin_dir ) as &$submenu ) {
				$submenu_dir = $this->get_dir( $submenu );
				if ( $submenu_dir && '-pages' === substr( $submenu, -6 ) ) {
					$this->current_submenu = $submenu;
					foreach ( scandir( $submenu_dir ) as &$page ) {
						$page_dir = $this->get_dir( "$submenu/$page" );
						if ( $page_dir && '.' !== $page[0] ) {
							$this->current_page = $page;
							$page_file = $this->get_file( "$submenu/$page/index.php" );
							if ( $page_file ) {
								$headers = get_file_data( $page_file, $default_headers );
							}
							
							if ( !empty( $headers['SanitizeCallback'] ) ) {
								if ( function_exists( $headers['SanitizeCallback'] ) ) {
									$sanitize_callback = $headers['SanitizeCallback'];
								} else {
									$this->error( "The function <code>{$headers['SanitizeCallback']}</code> does not exist." );
									$sanitize_callback = array( $this, 'default_sanitize_callback' );
								}
							} else {
								$sanitize_callback = array( $this, 'default_sanitize_callback' );
							}
							
							$option = 'mjm_' . substr( $submenu, 0, -6 ) . "_$page";
							register_setting( $option, $option, $sanitize_callback );
							$this->settings_sections();
						}
					}
					unset( $page );
				}
			}
			unset( $submenu );
		}
	}
	
	/**
	 * Formats an ID as a title.
	 * 
	 * @since Easy Settings 0.5
	 * 
	 * @param string $id The ID to format.
	 */
	public function format_title( $id ) {
		return ucwords( str_replace( array ( '-', '_' ), ' ', $id ) );
	}
	
	/**
	 * Gets the current page.
	 * 
	 * @since Easy Settings 0.5
	 */
	public function get_current_page() {
		$current_screen = get_current_screen();
		$base = explode( 'mjm-', $current_screen->base, 2 );
		return $base[1];
	}
	
	/**
	 * Gets the current submenu.
	 * 
	 * @since Easy Settings 0.5
	 */
	public function get_current_submenu() {
		$current_screen = get_current_screen();
		switch ( $current_screen->parent_file ) {
			case 'index.php':
				return 'dashboard';
			case 'edit.php':
				return 'posts';
			case 'upload.php':
				return 'media';
			case 'edit.php?post_type=page':
				return 'comments';
			case 'themes.php':
				return 'theme';
			case 'plugins.php':
				return 'plugins';
			case 'users.php':
				return 'users';
			case 'tools.php':
				return 'management';
			case 'options-general.php':
				return 'options';
			case 'settings.php':
				return 'settings';
			default:
				return $current_screen->parent_file;
		}
	}
	
	/**
	 * Checks if a file exists within {@see Easy_Settings::ROOT}, and if it
	 * does, returns the path to that file. If {@see Easy_Settings::TYPE} 
	 * is `'theme'` and a child theme is in use, checks the parent 
	 * {@see Easy_Settings::ROOT} as well.
	 * 
	 * @since Easy Settings 0.5
	 * 
	 * @param string $file The file
	 */
	public function get_file( $file ) {
		if ( 'plugin' === self::TYPE ) {
			if ( is_file( plugin_dir_path( __FILE__ ) . $file ) ) {
				return plugin_dir_path( __FILE__ ) . $file;
			}
		} elseif ( 'theme' === self::TYPE ) {
			if ( is_file( get_template_directory() . self::ROOT . "/$file" ) ) {
				return get_template_directory() . self::ROOT . "/$file";
			} elseif ( is_child_theme() && is_file( get_stylesheet_directory() . self::ROOT . "/$file" ) ) {
				return get_stylesheet_directory() . self::ROOT . "/$file";
			} else {
				return false;
			}
		}
	}
	
	/**
	 * Checks if a directory exists within {@see Easy_Settings::ROOT}, and if 
	 * so, returns the path to that directory. If {@see Easy_Settings::TYPE} is 
	 * `'theme'` and a child theme is in use, checks the parent 
	 * {@see Easy_Settings::ROOT} as well.
	 * 
	 * @since Easy Settings 0.5
	 * 
	 * @param string $dir The directory.
	 */
	public function get_dir( $dir ) {
		if ( 'plugin' === self::TYPE ) {
			if ( is_dir( plugin_dir_path( __FILE__ ) . $dir ) ) {
				return plugin_dir_path( __FILE__ ) . $dir;
			}
		} elseif ( 'theme' === self::TYPE ) {
			if ( is_dir( get_template_directory() . self::ROOT . "/$dir" ) ) {
				return get_template_directory() . self::ROOT . "/$dir";
			} elseif ( is_child_theme() && is_dir( get_stylesheet_directory() . self::ROOT . "/$dir" ) ) {
				return get_stylesheet_directory() . self::ROOT . "/$dir";
			} else {
				return false;
			}
		}
	}
	
	/**
	 * The default sanitize callback.
	 * 
	 * @since Easy Settings 0.5
	 * 
	 * @param array $input The input to sanitize.
	 */
	public function default_sanitize_callback( $input ) {
		foreach ( $input as &$value ) {
			$value = sanitize_text_field( $value );
		}
		unset( $value );
		return $input;
	}
	
	/**
	 * Adds an error to be displayed later.
	 * 
	 * @since Easy Settings 0.5
	 * 
	 * @param string $error The error to be displayed.
	 */
	public function error( $error ) {
		$this->errors[] = $error;
		if ( !has_action( 'admin_notices', array( $this, 'display_error' ) ) ) {
			add_action( 'admin_notices', array( $this, 'display_error' ) );
		}
	}
	
	/**
	 * Displays an error.
	 * 
	 * @since Easy Settings 0.5
	 */
	public function display_error() {
		foreach ( $this->errors as &$error ) { ?>
		<div class="error">
			<p><strong>Easy Settings Error:</strong> <?php echo $error; ?></p>
		</div>
<?php	}
	}
}

new Easy_Settings();