<?php namespace ProcessWire;

/**
 * ProcessWire ProcessController
 *
 * Loads and executes Process Module instance and determines access.
 * 
 * ProcessWire 3.x, Copyright 2018 by Ryan Cramer
 * https://processwire.com
 *
 */

/**
 * A Controller for Process* Modules
 *
 * Intended to be used by templates that call upon Process objects
 * 
 * @method string execute()
 *
 */
class ProcessController extends Wire {

	/**
	 * The default method called upon when no method is specified in the request
	 *
	 */
	 const defaultProcessMethodName = 'execute';

	/**
	 * The Process instance to execute
	 * 
	 * @var Process
	 *
	 */
	protected $process; 

	/**
	 * The name of the Process to execute (string)
	 * 
	 * @var string
	 *
	 */
	protected $processName;

	/**
	 * Error message if unable to load Process module
	 * 
	 * @var string
	 * 
	 */
	protected $processError = '';

	/**
	 * The name of the method to execute in this process
	 * 
	 * @var string
	 *
	 */ 
	protected $processMethodName;

	/**
	 * Process verbose module info
	 * 
	 * @var array
	 * 
	 */
	protected $processInfo = array();

	/**
	 * The prefix to apply to the Process name
	 *
	 * All related Processes would use the same prefix, i.e. "Admin"
	 * 
	 * @var string
	 *
	 */
	protected $prefix;

	/**
	 * Construct the ProcessController
	 *
	 */
	public function __construct() {
		$this->prefix = 'Process';
		$this->processMethodName = ''; // blank indicates default/index method
	}

	/**
	 * Set the Process to execute. 
	 * 
	 * @param Process $process
	 *
	 */
	public function setProcess(Process $process) {
		$this->process = $process; 
	}

	/**
	 * Set the name of the Process to execute. 
	 *
	 * No need to call this unless you want to override the one auto-determined from the URL.
	 *
	 * If overridden, then make sure the name includes the prefix, and don't bother calling the setPrefix() method. 
	 * 
	 * @param string $processName
	 *
	 */
	public function setProcessName($processName) {
		$this->processName = $this->sanitizer->name($processName); 
	}

	/**
	 * Set the name of the method to execute in the Process
	 *
	 * It is only necessary to call this if you want to override the default behavior. 
	 * The default behavior is to execute a method called "execute()" OR "executeSegment()" where "Segment" is 
	 * the last URL segment in the request URL. 
	 * 
	 * @param string $processMethod
	 *
	 */
	public function setProcessMethodName($processMethod) {
		$this->processMethodName = $this->sanitizer->name($processMethod); 
	}

	/**
	 * Set the class name prefix used by all related Processes
	 *
	 * This is prepended to the class name determined from the URL. 
	 * For example, if the URL indicates a process name is "PageEdit", then we would need a prefix of "Admin" 
	 * to fully resolve the class name. 
	 * 
	 * @param string $prefix
	 *
	 */
	public function setPrefix($prefix) {
		$this->prefix = $this->sanitizer->name($prefix); 
	}

	/**
	 * Determine and return the Process to execute
	 * 
	 * @return Process
	 *
	 */
	public function getProcess() {

		if($this->process) {
			$processName = $this->process->className();
		} else if($this->processName) {
			$processName = $this->processName;
		} else {
			return null;
		}

		// verify that there is adequate permission to execute the Process
		$permissionName = '';
		$info = $this->wire('modules')->getModuleInfoVerbose($processName);
		$this->processInfo = $info;
		if(!empty($info['permission'])) $permissionName = $info['permission']; 

		$this->hasPermission($permissionName, true); // throws exception if no permission
		
		if(!$this->process) {
			$module = $this->modules->getModule($processName, array('returnError' => true)); 
			if(is_string($module)) {
				$this->processError = $module;
				$this->process = null;
			} else {
				$this->process = $module;
			}
		}

		// set a process fuel, primarily so that certain Processes can determine if they are the root Process 
		// example: PageList when in PageEdit
		$this->wire('process', $this->process);
	
		return $this->process; 
	}

	/**
	 * Does the current user have permission to execute the given process name?
	 *
	 * Note: an empty permission name is accessible only by the superuser
	 * 
	 * @param string $permissionName
	 * @param bool $throw Whether to throw an Exception if the user does not have permission
	 * @return bool
	 * @throws ProcessControllerPermissionException
	 *
	 */
	protected function hasPermission($permissionName, $throw = true) {
		$user = $this->wire('user'); 
		if($user->isSuperuser()) return true; 
		if($permissionName && $user->hasPermission($permissionName)) return true; 
		if($throw) {
			throw new ProcessControllerPermissionException(
				sprintf($this->_('You do not have “%s” permission'), $permissionName)
			);
		}
		return false; 
	}

	/**
	 * Does user have permission for the given $method name in the current Process?
	 *
	 * @param string $method
	 * @param bool $throw Throw exception if not permission?
	 * @return bool
	 * @throws ProcessControllerPermissionException
	 *
	 */
	protected function hasMethodPermission($method, $throw = true) {
		// i.e. executeHelloWorld => helloWorld
		$urlSegment = $method;
		if(strpos($method, 'execute') === 0) list(,$urlSegment) = explode('execute', $method, 2);
		$urlSegment = $this->wire('sanitizer')->hyphenCase($urlSegment); 
		if(!$this->hasUrlSegmentPermission($urlSegment, $throw)) return false;
		return true;
	}

	/**
	 * Does user have permission for the given urlSegment in the current Process?
	 * 
	 * @param string $urlSegment
	 * @param bool $throw Throw exception if not permission?
	 * @return bool
	 * @throws ProcessControllerPermissionException
	 * 
	 */
	protected function hasUrlSegmentPermission($urlSegment, $throw = true) {
	
		if(empty($this->processInfo['nav']) || $this->wire('user')->isSuperuser()) return true;
		$hasPermission = true;
		$urlSegment = trim(strtolower($urlSegment), '.-_');

		foreach($this->processInfo['nav'] as $navItem) {
			if(empty($navItem['permission'])) continue;
			$navSegment = strtolower(trim($navItem['url'], './'));
			if(empty($navSegment)) continue;
			if(strpos($navSegment, '/') !== false) list($navSegment,) = explode($navSegment, '/', 2);
			$navSegmentAlt = str_replace('-', '', $navSegment);
			if($urlSegment === $navSegment || $urlSegment === $navSegmentAlt) {
				$hasPermission = $this->hasPermission($navItem['permission'], $throw);
				break;
			}
		}
	
		return $hasPermission;
	}

	/**
	 * Get the name of the method to execute with the Process
	 * 
	 * @param Process @process
	 * @return string
	 * @throws ProcessControllerPermissionException
	 *
	 */
	public function getProcessMethodName(Process $process) {

		$forceFail = false;
		$urlSegment1 = $this->wire('input')->urlSegment1;
		$method = self::defaultProcessMethodName; 
		$sanitizer = $this->wire('sanitizer');

		if($this->processMethodName) {
			// the method to use has been preset with the setProcessMethodName() function
			$method = $this->processMethodName;
			if($method !== self::defaultProcessMethodName) {
				$this->hasMethodPermission($method);
			}
			
		} else if(strlen($urlSegment1) && !$this->wire('user')->isGuest()) {
			// determine requested method from urlSegment1
			// $urlSegment1 = trim($this->wire('sanitizer')->hyphenCase($urlSegment1, array('allow' => 'a-z0-9_')), '_');
			if(ctype_alpha($urlSegment1)) {
				$methodName = ucfirst($urlSegment1);
				$hyphenName = $urlSegment1;
			} else {
				$methodName = trim($sanitizer->pascalCase($urlSegment1, array('allowUnderscore' => true)), '_');
				$hyphenName = trim($sanitizer->hyphenCase($methodName, array('allowUnderscore' => true)), '_');
			}
			if($hyphenName != strtolower($urlSegment1) && strtolower($methodName) != strtolower($urlSegment1)) {
				// if urlSegment changed from sanitization, likely not in valid format
				$forceFail = true;
			} else {
				// valid 
				$method .= $methodName; // execute => executeHelloWorld
				$this->hasUrlSegmentPermission($hyphenName);
			}
		}
	
		if(!$forceFail) {
			if($method === 'executed') return '';
			if(method_exists($process, $method)) return $method;
			if(method_exists($process, "___$method")) return $method;
			if($process->hasHook($method . '()')) return $method;
		}
	
		// fallback to the unknown, if there is an unknown (you never know)
		$method = 'executeUnknown';
		if(method_exists($process, $method) || method_exists($process, "___$method")) return $method;
		
		return '';
	}

	/**
	 * Execute the process and return the resulting content generated by the process
	 * 
	 * @return string
	 * @throws ProcessController404Exception
	 *	
	 */
	public function ___execute() {

		$debug = $this->wire('config')->debug; 
		$breadcrumbs = $this->wire('breadcrumbs'); 
		$headline = $this->wire('processHeadline'); 
		$numBreadcrumbs = $breadcrumbs ? count($breadcrumbs) : null;
		$process = $this->getProcess();
		
		if(!$process) {
			throw new ProcessController404Exception("Process does not exist: $this->processError");
		}

		// determine method (throws ProcessControllerPermissionException if no access)
		$method = $this->getProcessMethodName($process);
		
		if(!$method) {
			throw new ProcessController404Exception("Unrecognized path");
		}
	
		// call method from Process (and time it if debug mode enabled)
		$className = $process->className();
		if($debug) Debug::timer("$className.$method()"); 
		$content = $process->$method();
		if($debug) Debug::saveTimer("$className.$method()"); 
	
		// setup breadcrumbs if in some method other than the main execute() method
		if($method !== 'execute') {
			// some method other than the main one
			if(!is_null($numBreadcrumbs) && $numBreadcrumbs === count($breadcrumbs)) {
				// process added no breadcrumbs, but there should be more
				if($headline === $this->wire('processHeadline')) {
					$process->headline(str_replace('execute', '', $method));
				}
				$href = substr($this->wire('input')->url(), -1) == '/' ? '../' : './';
				$process->breadcrumb($href, $this->processInfo['title']); 
			}
		}
	
		// triggered "executed" (execute done) hook
		$process->executed($method);

		if(empty($content) || is_bool($content)) {
			$content = $process->getViewVars();
		}
		
		if(is_array($content)) {
			// array of returned content indicates variables to send to a view
			if(count($content) || $process->getViewFile()) {
				$viewFile = $this->getViewFile($process, $method); 
				if($viewFile) {
					// get output from a separate view file
					$template = $this->wire(new TemplateFile($viewFile));	
					foreach($content as $key => $value) {
						$template->set($key, $value);
					}
					$content = $template->render();
				}
			} else {
				$content = '';
			}
		}

		return $content; 
	}

	/**
	 * Given a process and method name, return the first matching valid view file for it
	 * 
	 * @param Process $process
	 * @param string $method If omitted, 'execute' is assumed
	 * @return string
	 * 
	 */
	protected function getViewFile(Process $process, $method = '') {
		
		$viewFile = $process->getViewFile();
		if($viewFile) return $viewFile;
	
		if(empty($method)) $method = 'execute';
		$className = $process->className();
		$viewPath = $this->wire('config')->paths->$className;
		$method2 = ''; // lowercase hyphenated version
		$method3 = ''; // lowercase hyphenated, without leading execute
		if(strtolower($method) != $method) {
			// lowercase hyphenated version
			$method2 = trim(strtolower(preg_replace('/([A-Z]+)/', '-$1', $method)), '-');
			// without a leading 'execute-' or 'execute'
			$method3 = str_replace(array('execute-', 'execute'), '', $method2);
		}
		
		if(is_dir($viewPath . 'views')) {
			// check in a /ModuleName/views/ directory for one of the following:
			// views/execute.php (only if method name is 'execute')
			// views/executeSomeMethod.php
			// views/execute-some-method.php
			// views/some-method.php (preferable)
			$_viewPath = $viewPath;
			$viewPath .= 'views/';
			$viewFile = $viewPath . $method . '.php'; // i.e. views/execute.php or views/executeSomething.php
			if(is_file($viewFile)) return $viewFile;
			if($method2) {
				// convert executeSomething to execute-something or thisThat to this-that
				$viewFile = $viewPath . $method2 . '.php'; // i.e. execute-something.php
				if(is_file($viewFile)) return $viewFile;
			}
			if($method != 'execute' && $method3) {
				$viewFile = $viewPath . $method3 . '.php'; // i.e. something.php or some-method.php
				if(is_file($viewFile)) return $viewFile;
			}
			$viewPath = $_viewPath; // restore, since didn't find it in /views/ 
		} 
	
		// look for view file in same dir as module
		if($method == 'execute') {
			$viewFiles = array(
				"$className.view.php", // ModuleName.view.php
				"$className-execute.view.php", // alt1: ModuleName-execute.view.php
				"execute.view.php", // alt2: just execute.view.php (no ModuleName)
			);
		} else {
			$viewFiles = array(
				"$className-$method.view.php", // ModuleName.executeSomething.view.php
				"$method.view.php", // executeSomething.view.php
			);
			if($method2) {
				$viewFiles[] = "$className-$method2.view.php"; // ModuleName-execute-something.view.php
				$viewFiles[] = "$method2.view.php"; // execute-something.view.php
			}
			if($method3) {
				$viewFiles[] = "$className-$method3.view.php"; // ModuleName-something.view.php
				$viewFiles[] = "$method3.view.php"; // something.view.php
			}
		}

		// now determine which of the possible view files actually exists
		$viewFile = '';
		foreach($viewFiles as $file) {
			if(is_file($viewPath . $file)) {
				$viewFile = $viewPath . $file;
				break;
			}
		}
		
		return $viewFile;
	}

	/**
	 * Generate a message in JSON format, for use with AJAX output
	 * 
	 * @param string $msg
	 * @param bool $error
	 * @return string JSON encoded string
	 *
	 */
	public function jsonMessage($msg, $error = false) {
		return json_encode(array(
			'error' => $error, 
			'message' => $msg
		)); 
	}

	/**
	 * Is this an AJAX request?
	 *
	 * @return bool
	 * 
	 */
	public function isAjax() {
		return isset($_SERVER['HTTP_X_REQUESTED_WITH']) && ($_SERVER['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest');
	}

}