<?php

if(class_exists('PermissionDescription')) return;

require_once("include/permissions.php");
require_once("include/language.php");
require_once("include/text.php");


/**
 * Encapsulates information the ACL dialog requires to describe
 * permission settings for an item with an empty ACL.
 * i.e the caption, icon, and tooltip for the no-ACL option in the ACL dialog.
 */
class PermissionDescription  {

	private $global_perm;
	private $channel_perm;
	private $fallback_description;
	
	/**
	 * Constructor is private.
	 * Use static methods fromGlobalPermission(), fromStandalonePermission(), or fromDescription()
	 * to create instances.
	 */
	private function __construct($global_perm, $channel_perm, $description = '') {

		$this->global_perm  = $global_perm;
		$this->channel_perm = $channel_perm;
		
		$this->fallback_description = ($description  == '') ? t('Visible to your default audience') : $description;
	}

	/**
	 * If the interpretation of an empty ACL can't be summarised with a global default permission
	 * or a specific permission setting then use this method and describe what it means instead.
	 * Remember to localize the description first.
	 *
	 * @param  string $description - the localized caption for the no-ACL option in the ACL dialog.
	 * @return a new instance of PermissionDescription
	 */
	public static function fromDescription($description) {
		return new PermissionDescription('', 0x80000, $description);
	}


	/**
	 * Use this method only if the interpretation of an empty ACL doesn't fall back to a global
	 * default permission. You should pass one of the constants from boot.php - PERMS_PUBLIC,
	 * PERMS_NETWORK etc.
	 * 
	 * @param  integer $perm - a single enumerated constant permission - PERMS_PUBLIC, PERMS_NETWORK etc.
	 * @return a new instance of PermissionDescription
	 */
	public static function fromStandalonePermission($perm) {

		$result = new PermissionDescription('', $perm);
		
		$checkPerm = $this->get_permission_description();
		if ($checkPerm == $this->fallback_description) {
			$result = null;
			logger('null PermissionDescription from unknown standalone permission: ' . $perm ,LOGGER_DEBUG, LOG_ERROR);
		}

		return $result;
	}

	/**
	 * This is the preferred way to create a PermissionDescription, as it provides the most details.
	 * Use this method if you know an empty ACL will result in one of the global default permissions 
	 * being used, such as channel_r_stream (for which you would pass 'view_stream').
	 * 
	 * @param  string $permname - a key for the global perms array from get_perms() in permissions.php,
	 *         e.g. 'view_stream', 'view_profile', etc.
	 * @return a new instance of PermissionDescription
	 */
	public static function fromGlobalPermission($permname) {

		$result = null;

		$global_perms = get_perms();

		if (array_key_exists($permname, $global_perms)) {

			$permDetails = $global_perms[$permname];

			// It should be OK to always just read the permissions from App::$channel
			//
			// App::$profile is a union of channel and profile fields.
			// The distinction is basically that App::$profile is pointing to the resource
			// being observed. App::$channel is referring to the current logged-in channel
			// member (if this is a local channel) e.g. the observer. We only show the ACL
			// widget to the page owner (observer and observed are the same) so in that case
			// I believe either may be safely used here.
			$channelPerm = \App::$channel[$permDetails[0]];
			$result = new PermissionDescription($permDetails[1], $channelPerm);
		} else {
			// The acl dialog can handle null arguments, but it shouldn't happen
			logger('null PermissionDescription from unknown global permission: ' . $permname ,LOGGER_DEBUG, LOG_ERROR);
		}
		return $result;
	}


	/**
	 * Gets a localized description of the permission, or a generic message if the permission
	 * is unknown.
	 *
	 * @return string description
	 */
	public function get_permission_description() {

		switch($this->channel_perm) {			

			case 0:              return t('Only me');
			case PERMS_PUBLIC:   return t('Public');
			case PERMS_NETWORK:  return t('Anybody in the $Projectname network');
			case PERMS_SITE:     return sprintf(t('Any account on %s'), \App::get_hostname());
			case PERMS_CONTACTS: return t('Any of my connections');
			case PERMS_SPECIFIC: 
				// Because we're describing the permissions of an item with an empty ACL,
				// the owner will be the only person able to see it if the permissions are 
				// set to "only specified connections".
				return t('Only me (only specified contacts and me)'); 
			case PERMS_AUTHED:   return t('Anybody authenticated (could include visitors from other networks)');
			case PERMS_PENDING:  return t('Any connections including those who haven\'t yet been approved');
			default:             return $this->fallback_description;
		}
	}

	/**
	 * Returns an icon css class name if an appropriate one is available, e.g. "fa-globe" for Public,
	 * otherwise returns empty string. 
	 *
	 * @return string icon css class name (often FontAwesome)
	 */
	public function get_permission_icon() {

		switch($this->channel_perm) {			

			case 0:/* only me */ return 'fa-eye-slash';
			case PERMS_PUBLIC:   return 'fa-globe';
			case PERMS_NETWORK:  return 'fa-share-alt-square'; // fa-share-alt-square is very similiar to the hubzilla logo, but we should create our own logo class to use
			case PERMS_SITE:     return 'fa-sitemap'; 
			case PERMS_CONTACTS: return 'fa-group'; 
			case PERMS_SPECIFIC: 
				// Because we're describing the permissions of an item with an empty ACL,
				// the owner will be the only person able to see it if the permissions are 
				// set to "only specified connections".
				return 'fa-eye-slash'; 
			case PERMS_AUTHED:   return '';
			case PERMS_PENDING:  return '';
			default:             return '';
		}
	}


	/**
	 * Returns a localized description of where the permission came from, if this is known.
	 * If it's not know, or if the permission is standalone and didn't come from a default
	 * permission setting, then empty string is returned.
	 *
	 * @return string description or empty string
	*/
	public function get_permission_origin_description() {

		switch($this->global_perm) {			

			case PERMS_R_STREAM:  return t('This is your default setting for the audience of your normal stream, and posts.');
			case PERMS_R_PROFILE: return t('This is your default setting for who can view your default channel profile');
			case PERMS_R_ABOOK:   return t('This is your default setting for who can view your connections');
			case PERMS_R_STORAGE: return t('This is your default setting for who can view your file storage and photos');
			case PERMS_R_PAGES:   return t('This is your default setting for the audience of your webpages');
			default:              return '';
		}
	}

}
