<?php namespace ProcessWire;

/**
 * ProcessWire User Process
 *
 * For more details about how Process modules work, please see: 
 * /wire/core/Process.php 
 * 
 * ProcessWire 3.x, Copyright 2020 by Ryan Cramer
 * https://processwire.com
 * 
 * @property int $maxAjaxQty
 *
 */

class ProcessUser extends ProcessPageType {

	static public function getModuleInfo() {
		return array(
			'title'      => __('Users', __FILE__), // getModuleInfo title
			'version'    => 107,
			'summary'    => __('Manage system users', __FILE__), // getModuleInfo summary
			'permanent'  => true,
			'permission' => 'user-admin',
			'icon'       => 'group',
			'useNavJSON' => true,
			'searchable' => 'users' 
		);
	}

	/**
	 * Construct and set default config values
	 * 
	 */
	public function __construct() {
		$this->set("maxAjaxQty", 25);
		return parent::__construct();
	}

	/**
	 * Init and prepare for execute methods
	 * 
	 */
	public function init() {
		$this->wire('pages')->addHookBefore('save', $this, 'hookPageSave');
		parent::init();
		if($this->lister) $this->lister->addHookBefore('execute', $this, 'hookListerExecute');

		// make this field translatable
		$roles = $this->wire('fields')->get('roles');
		$roles->label = $this->_('Roles');
		$roles->description = $this->_("User will inherit the permissions assigned to each role. You may assign multiple roles to a user. When accessing a page, the user will only inherit permissions from the roles that are also assigned to the page's template."); // Roles description
	}

	/**
	 * Determine whether Lister should be used or not
	 * 
	 * @return bool
	 * 
	 */
	protected function useLister() {
		return $this->wire('user')->hasPermission('page-lister'); 
	}

	/**
	 * Output JSON list of navigation items for this (intended to for ajax use)
	 * 
	 * @param array $options
	 * @return string|array
	 *
	 */
	public function ___executeNavJSON(array $options = array()) {

		$max = $this->maxAjaxQty > 0 && $this->maxAjaxQty <= 100 ? (int) $this->maxAjaxQty : 50;

		if(empty($options) && $this->pages->count("id>0") > $max) {
			$user = $this->wire('user');
			$userAdminAll = $user->isSuperuser() ? $this->wire('pages')->newNullPage() : $this->wire('permissions')->get('user-admin-all');
			/** @var PagePermissions $pagePermissions */
			$pagePermissions = $this->wire('modules')->get('PagePermissions');
			$items = array();
			foreach($this->wire('roles') as $role) {
				if($userAdminAll->id && !$pagePermissions->userCanAssignRole($role)) continue;
				$cnt = $this->pages->count("roles=$role");
				$item = array(
					'id'   => $role->id,
					'name' => $role->name,
					'cnt'  => sprintf($this->_n('%d user', '%d users', $cnt), $cnt)
				);
				$items[] = $item;
			}
			$options['itemLabel'] = 'name';
			$options['itemLabel2'] = 'cnt';
			$options['add'] = 'add/';
			$options['items'] = $items;
			$options['edit'] = "?roles={id}";
		}

		return parent::___executeNavJSON($options);
	}
	
	/**
	 * Add item of this page type
	 *
	 * @return string
	 *
	 */
	public function ___executeAdd() {

		// use parent method if there are no custom user parents or templates
		$config = $this->wire()->config;
		if(count($config->usersPageIDs) < 2 && count($config->userTemplateIDs) < 2) return parent::___executeAdd();
		
		$input = $this->wire()->input;
		$pages = $this->wire()->pages;
		$parentId = (int) $input->get('parent_id');
		$parent = $parentId ? $pages->get($parentId) : null;
		$userTemplates = $this->pages->getTemplates();
		$userParentIds = $this->pages->getParentIDs();

		// if requested parent not one allowed by config.usersPageIDs then disregard it
		if($parent && !in_array($parent->id, $userParentIds, true)) $parent = null;

		// delegate to ProcessPageAdd
		$editor = $this->wire()->modules->getModule('ProcessPageAdd'); /** @var ProcessPageAdd $editor */
		$this->editor = $editor;
		$editor->setEditor($this); // set us as the parent editor

		// identify parent(s) allowed
		if(count($userParentIds) > 1 && $parent) {
			// more than one parent allowed but only one requested
			$parents = $pages->newPageArray();
			$parents->add($parent);
			$editor->parent_id = $parent->id;
			$editor->setPredefinedParents($parents);
		} else {
			// one or more parents allowed
			$editor->setPredefinedParents($pages->getById($userParentIds));
		}

		// identify template(s) allowed
		if(count($userTemplates) < 2) {
			// only one user template allowed
			$editor->template = $this->template;
		} else if($parent) {
			// parent specified, reduce to only allowed templates for parent
			$childTemplates = $parent->template->childTemplates;
			if(count($childTemplates)) {
				foreach($userTemplates as $key => $template) {
					/** @var Template $template */
					if(!in_array($template->id, $childTemplates)) unset($userTemplates[$key]);
				}
			}
			if(!count($userTemplates)) $userTemplates = array($this->template);
		}

		$editor->setPredefinedTemplates($userTemplates);

		try {
			$out = $editor->execute();
		} catch(\Exception $e) {
			$out = '';
			$this->error($e->getMessage());
			if($input->is('POST')) {
				$this->wire()->session->location("./" . ($parentId ? "?parent_id=$parentId" : ""));
			}
		}

		$this->browserTitle($this->page->get('title|name') . " > $this->addLabel");

		return $out;
	}
	

	/**
	 * Hook to ProcessPageLister::execute method to adjust selector to show specific roles
	 * 
	 * @param HookEvent $event
	 * 
	 */
	public function hookListerExecute($event) {
		
		$role = (int) $this->wire()->session->getFor($this, 'listerRole');
		if(!$role) return;

		/** @var ProcessPageLister $lister */
		$lister = $event->object;
		$defaultSelector = $lister->defaultSelector;
		if(strpos($defaultSelector, 'roles=') !== false) {
			$defaultSelector = preg_replace('/\broles=\d*/', "roles=$role", $defaultSelector);
		} else {
			$defaultSelector .= ", roles=$role";
		}
		$lister->defaultSelector = $defaultSelector;
	}

	/**
	 * Get settings to be used for Lister
	 * 
	 * @param ProcessPageLister $lister
	 * @param string $selector
	 * @return array
	 * 
	 */
	protected function getListerSettings(ProcessPageLister $lister, $selector) {
		
		$settings = parent::getListerSettings($lister, $selector);
		$selector = '';
		$role = (int) $this->wire()->input->get('roles');
		$user = $this->wire()->user;
		$session = $this->wire()->session;
		$ajax = $this->wire('config')->ajax;

		if($role) {
			$lister->resetLister();
			$session->setFor($this, 'listerRole', $role);
		} else if(!$ajax) {
			if((int) $session->getFor($this, 'listerRole') > 0) {
				$lister->resetLister();
				$session->setFor($this, 'listerRole', 0);
			}
		} else {
			$role = $session->getFor($this, 'listerRole');
		}

		if(!$role && !$user->isSuperuser()) {
			$userAdminAll = $this->wire()->permissions->get('user-admin-all');
			if($userAdminAll->id && !$user->hasPermission($userAdminAll)) {
				// system has user-admin-all permission, and user doesn't have it
				// so limit them only to the permission user-admin-[role] roles that they have assigned
				$roles = array();
				foreach($user->getPermissions() as $permission) {
					if(strpos($permission->name, 'user-admin-') !== 0) continue;
					$roleName = str_replace('user-admin-', '', $permission->name);
					$rolePage = $this->wire('roles')->get($roleName);
					if($rolePage->id) $roles[] = $rolePage->id;
				}
				// allow them to view users that only have guest role
				$config = $this->wire()->config;
				$guestRoleID = $config->guestUserRolePageID;
				$guestUserID = $config->guestUserPageID;
				$selector .= ", id!=$guestUserID, roles=(roles.count=1, roles=$guestRoleID)";
				if(count($roles)) {
					$selector .= ", roles=(roles=" . implode('|', $roles) . ")"; // string of | separated role IDs
				}
			}
		}

		$settings['initSelector'] .= $selector;
		$settings['defaultSelector'] = "name%=, roles=" . ($role ? $role : '');
		$settings['delimiters'] = array('roles' => ', ');
		$settings['allowBookmarks'] = true;

		return $settings;
	}

	/**
	 * Get the Page being edited, when applicable
	 * 
	 * @return NullPage|Page
	 * 
	 */
	public function getPage() {
		$page = parent::getPage();
		if($page->id && !$page->get('_rolesPrevious') && $this->wire('input')->post('roles') !== null) {
			$page->setQuietly('_rolesPrevious', clone $page->roles); 
		}
		return $page;
	}

	/**
	 * Return array of roles editable by current user for user $page
	 * 
	 * @param User $page
	 * @return array of role names indexed by role ID
	 * 
	 */
	protected function getEditableRoles(User $page) {
		/** @var User $user */
		$user = $this->wire('user');
		$superuser = $user->isSuperuser();
		$editableRoles = array();
		$userAdminAll = $this->wire('permissions')->get('user-admin-all');
		
		foreach($this->wire('roles') as $role) {
			if($role->name == 'guest') continue;
			// if non-superuser editing a user, don't allow them to assign new roles with user-admin permission, 
			// unless the user already has the role checked, OR the non-superuser has user-admin-all permission
			if(!$superuser && $role->hasPermission('user-admin') && !$page->hasPermission('user-admin')) {
				if($userAdminAll->id && $user->hasPermission($userAdminAll)) {
					// allow it if the non-superuser making edits has user-admin-all
				} else {
					// do not allow
					continue;
				}
			}
			$editableRoles[$role->id] = $role->name;
		}

		if(!$superuser) {
			if($userAdminAll->id && !$user->hasPermission($userAdminAll)) {
				foreach($editableRoles as $roleID => $roleName) {
					if(!$user->hasPermission("user-admin-$roleName")) {
						unset($editableRoles[$roleID]);
					}
				}
			}
			/*
			$numEditableRoles = 0;
			foreach($page->roles as $role) {
				if(isset($editableRoles[$role->id])) $numEditableRoles++;
			}
			if($numEditableRoles == 1 && count($editableRoles) == 2) {
				// if there is only one editable role here, then removal of it would
				// prevent this user from being able to make further edits, so we 
				// count it as not-editable in that case
				foreach($page->roles as $role) {
					if($role->name == 'guest') continue;
					unset($editableRoles[$role->id]);
				}
			}
			*/
		}
		
		return $editableRoles;
	}

	/**
	 * Edit user
	 * 
	 * @return array|string
	 * 
	 */
	public function ___executeEdit() {

		/** @var User $user */
		$user = $this->wire('user');
		
		if(!$user->isSuperuser()) {
			// prevent showing superuser role at all
			$this->addHookAfter('InputfieldPage::getSelectablePages', $this, 'hookGetSelectablePages'); 
		}
		
		$this->addHookAfter('ProcessPageEdit::buildForm', $this, 'hookPageEditBuildForm'); 
		
		$out = parent::___executeEdit();
		
		/** @var User $page Available only after executeEdit() */
		$page = $this->getPage();

		$this->wire('config')->js('ProcessUser', array(
			'editableRoles' => array_keys($this->getEditableRoles($page)),
			'notEditableAlert' => $this->_('You may not change this role'),
		));

		return $out; 
	}

	/**
	 * Hook to InputfieldPage::getSelectablePages to target the "roles" field
	 * 
	 * @param HookEvent $event
	 * 
	 */
	public function hookGetSelectablePages($event) {
		/** @var InputfieldPage $inputfield */
		$inputfield = $event->object;
		if($inputfield->attr('name') != 'roles') return;
		$suRoleID = $this->wire()->config->superUserRolePageID;
		foreach($event->return as $role) {
			if($role->id == $suRoleID) $event->return->remove($role);
		}
	}

	/**
	 * Hook to ProcessPageEdit::buildForm to adjust User edit form before presenting to user
	 * 
	 * @param HookEvent $event
	 * 
	 */
	public function hookPageEditBuildForm(HookEvent $event) {
		$form = $event->return;
		/** @var InputfieldSelect $theme */
		$theme = $form->getChildByName('admin_theme');
		if(!$theme) return;
		if(!$theme->attr('value')) {
			$theme->attr('value', $this->wire('config')->defaultAdminTheme); 
		}
	}
	
	/**
	 * Hook before Pages::save()
	 * 
	 * Perform a security check to make sure that a non-superuser isn't assigning superuser access to 
	 * themselves or someone else. Plus perform addition role add/remove checks. 
	 *
	 * @param HookEvent $event
	 * @throws WireException
	 * 
	 */
	public function hookPageSave(HookEvent $event) {

		$arguments = $event->arguments; 
		$page = $arguments[0]; 
		
		if(!$page instanceof User && !in_array($page->template->id, $this->wire('config')->userTemplateIDs)) {
			// don't handle anything other than User page saves
			return;
		}

		$pages = $this->wire('pages');
		$user = $this->wire('user');
		$superuser = $user->isSuperuser();
		$suRole = $this->wire('roles')->get($this->wire('config')->superUserRolePageID); 

		// don't allow removal of the guest role
		if(!$page->roles->has("name=guest")) {
			$page->roles->add($this->wire('roles')->get('guest')); 	
		}

		// check if user is editing themself
		if($user->id == $page->id) {
			// if so, we have to get a fresh copy of their account to see what it had before they changed it
			$copy = clone $page;		// keep a copy that doesn't go through the uncache process
			$pages->uncache($page); 	// take it out of the cache
			$user = $pages->get($page->id); // get a fresh copy of their account from the DB (pre-modified)
			$pages->cache($copy); 		// put the modified version back into the cache
			$arguments[0] = $copy;		// restore it to the arguments sent to $pages->save 
			$event->arguments = $arguments;
			$page = $copy;

			// don't let superusers remove their superuser role
			if($superuser && !$page->roles->has($suRole)) {
				throw new WireException($this->_("You may not remove the superuser role from yourself")); 
			}
		} 

		if(!$superuser) {
			if($page->roles->has("name=superuser") || $page->roles->has($suRole)) { 
				throw new WireException($this->_("You may not assign the superuser role"));
			}
			$this->checkSaveRoles($user, $page);
			$this->checkSaveUserAdminAll($user, $page);
		}
	}

	/**
	 * Perform a general check for saving the roles field, making sure added/removed roles are okay
	 * 
	 * @param User $user
	 * @param User|Page $page
	 * 
	 */
	protected function checkSaveRoles(User $user, Page $page) {
		
		if($user->isSuperuser()) return;
		
		/** @var PageArray $rolesPrevious Set to page by the ProcessUser::getPage() method */
		$rolesPrevious = $page->get('_rolesPrevious');
		if(!$rolesPrevious || ((string) $rolesPrevious) === ((string) $page->roles)) return;

		$editableRoles = $this->getEditableRoles($page);
		$addedRoles = array();
		$removedRoles = array();

		// determine added and removed roles
		foreach($page->roles as $role) {
			if(!$rolesPrevious->has($role)) $addedRoles[$role->id] = $role;
		}
		foreach($rolesPrevious as $role) {
			if(!$page->roles->has($role)) $removedRoles[$role->id] = $role;
		}
		
		// if any added or removed roles are not consistent with editable roles, then reverse the change
		// this is not likely to ever occur but is here for redundancy
		foreach($addedRoles as $role) {
			if($role->name == 'guest') continue;
			if(!isset($editableRoles[$role->id])) {
				$page->roles->remove($role);
				$this->error("Role $role->name may not be added"); 
			}
		}
		foreach($removedRoles as $role) {
			if(!isset($editableRoles[$role->id])) {
				$page->roles->add($role);
				$this->error("Role $role->name may not be removed"); 
			}
		}
	}

	/**
	 * Perform checks for when "user-admin-all" permission is installed and user does not have it
	 * 
	 * @param User $user
	 * @param User|Page $page
	 * 
	 */
	protected function checkSaveUserAdminAll(User $user, Page $page) {
		
		if($user->isSuperuser()) return;
		
		$userAdminAll = $this->wire('permissions')->get('user-admin-all');
		if(!$userAdminAll->id || $user->hasPermission($userAdminAll)) return;
		
		// user-admin-all permission is installed and user doesn't have it
		// check that the role assignments are valid
		
		/** @var Pages $pages */
		$pages = $this->wire('pages');
		$changedUser = $page;
		$pages->uncache($page, array('shallow' => true));
		$originalUser = $this->wire('users')->get($page->id); // get a fresh, unmodified copy
		if(!$originalUser->id) return;
		
		/** @var PagePermissions $pagePermissions */
		$pagePermissions = $this->wire('modules')->get('PagePermissions');
		$removedRoles = array();

		foreach($originalUser->roles as $role) {
			if(!$changedUser->roles->has($role)) {
				// role was removed
				if(!$pagePermissions->userCanAssignRole($role)) {
					$changedUser->roles->add($role);
					$this->error(sprintf($this->_('You are not allowed to remove role: %s'), $role->name));
				} else {
					$removedRoles[] = $role;
				}
			}
		}
		
		foreach($changedUser->roles as $role) {
			if(!$originalUser->roles->has($role)) {
				// role was added
				if(!$pagePermissions->userCanAssignRole($role)) {
					$changedUser->roles->remove($role);
					$this->error(sprintf($this->_('You are not allowed to add role: %s'), $role->name));
				}
			}
		}

		if(count($removedRoles) && !$changedUser->editable()) {
			$this->error($this->_('You removed role(s) that that will prevent your edit access to this user. Roles have been restored.'));
			foreach($removedRoles as $role) $changedUser->roles->add($role);
		}
	}
	
}