<?php

/**
 * Vvveb
 *
 * Copyright (C) 2022  Ziadin Givan
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */

namespace Vvveb\System\Component;

use function Vvveb\dashesToCamelCase;
use function Vvveb\removeJsonComments;
use Vvveb\System\Cache;
use Vvveb\System\Core\View;

if (! defined('COMPONENT_CACHE_FLAG_LOCK')) {
	define('COMPONENT_CACHE_FLAG_LOCK', PHP_INT_MIN + 1);
	define('COMPONENT_CACHE_FLAG_REGENERATE', PHP_INT_MIN + 2);

	//time
	define('COMPONENT_CACHE_EXPIRE_DELAY', 5); //real expiration time +5 seconds
	define('COMPONENT_CACHE_WAIT', 1); //wait for cache generation
	define('COMPONENT_CACHE_MAX_WAIT_RETRY', 3); //wait for cache generation
	define('COMPONENT_CACHE_LOCK_EXPIRE', 20); //lock can not be set more than COMPONENT_CACHE_LOCK_EXPIRE seconds
	define('COMPONENT_CACHE_EXPIRE', 20);
}

class Component {
	static private $instance;

	private $queue;

	private $components = [];

	private $componentsFile;

	private $loaded;

	private $content;

	private $view;

	private $app;

	private $documentType = 'html';

	private $cache = true;

	static function getInstance($view = false, $regenerate = false, $content = false, $app = null) {
		if (self :: $instance === NULL) {
			if (! $view) {
				$view = View::getInstance();
			}
			self :: $instance =  new self($view, $regenerate, $content);
		}

		return self :: $instance;
	}

	function __construct($view, $regenerate = false, $content = false, $app = null) {
		if ($this->loaded) {
			return true;
		}

		$this->app = $app ?? APP;

		if (! $view) {
			$view = View::getInstance();
		}

		$this->view         = $view;

		$this->componentsFile = $view->serviceTemplate() . '.component';
		$this->content        = $content;

		if ((! file_exists($this->componentsFile)) || $regenerate) {
			$this->generateRequiredComponents();
			$this->saveTemplateComponents();
			$this->loadComponents();
			$this->loaded = true;
		} else {
		}

		if ($this->loaded) {
			return true;
		}

		$this->loadTemplateComponents();
		$this->loadComponents();
		$this->loaded = true;
	}

	function isComponent($name) {
		return isset($this->components[$name]);
	}

	function getComponent($name) {
		return $this->components[$name] ?? [];
	}

	function loadComponents() {
		$view = $this->view;

		$cache     = [];
		$objs      = [];
		$namespace = 'component';

		$notFound404 = false;

		if (is_array($this->components)) {
			foreach ($this->components as $component => $instances) {
				if (strpos($component, 'plugin') === 0) {
					$template   = str_replace('plugin', '', $component);
					$p          = strrpos($template, '-');
					$pluginName = substr($template, 1, $p - 1);
					$nameSpace  = substr($template, $p + 1);
					$app        = '';

					$pluginClassName = dashesToCamelCase($pluginName);
					$class           = "Vvveb\Plugins\\$pluginClassName\Component\\$nameSpace";
					$file            = DIR_PLUGINS . "$pluginName/component/" . str_replace('-', '/', $nameSpace) . '.php';
				} else {
					$class = '\Vvveb\Component\\' . str_replace('-', '\\', $component);
					$file  = DIR_ROOT . $this->app . DS . 'component' . DS . str_replace('-', '/', $component) . '.php';
				}

				$component = str_replace('-', '_', $component);

				if (file_exists($file)) {
					include_once $file;

					foreach ($instances as $instance => $options) {
						$obj      = new $class($options);

						if ($obj->cacheExpire && $this->cache && ($cacheKey = $obj->cacheKey())) {
							$cacheExpireKey                  = $cacheKey . '_expire';
							$cache[]                         = $cacheKey;
							$cache[]                         = $cacheExpireKey;
							$obj->component                  = $component;
							$objs[$obj->cacheKey][$instance] = $obj;
						} else {
							$results = $obj->results();

							if ($results !== false && $results !== null) {
								$results['_instance'] = $obj;
							}

							$comp            = &$view->_component[$component];
							$comp[$instance] = $results;

							if (isset($results['404']) && $results['404'] == true) {
								$notFound404 = true;
							}
						}
					}
				}
			}

			if ($this->cache) {
				//get cached data
				$cacheDriver = Cache::getInstance();
				//$cacheDriver = new Memcached();
				$null = [];
				$data = $cacheDriver->getMulti($namespace, $cache, SITE_ID) ?? [];

				foreach ($objs as $cacheKey => $instances) {
					foreach ($instances as $index => $instance) {
						if (! isset($data[$cacheKey]) || ! is_array($data[$cacheKey])) {
							$data[$cacheKey] = [];
						}

						$component                    = $instance->component;
						$component                    = str_replace('-', '_', $component);
						$data[$cacheKey]['_instance'] = $instance;
						$comp                         = &$view->_component[$component];
						$comp[$index]                 = $data[$cacheKey];

						if (isset($comp[$index]['404']) && $comp[$index]['404'] == true) {
							$notFound404 = true;
						}
					}

					//cache hit, remove from sql regeneration queue
					$cacheExpireKey = $cacheKey . '_expire';

					//if no lock set (! -1) and cache is expiring then set lock and set for regeneration
					if (! isset($data[$cacheExpireKey]) || ! isset($data[$cacheKey]) ||
						($data[$cacheExpireKey] && ($data[$cacheExpireKey] > 0) &&
						($data[$cacheExpireKey] + COMPONENT_CACHE_EXPIRE_DELAY) < $_SERVER['REQUEST_TIME'])) {
						$cacheDriver->set($namespace, $cacheExpireKey, COMPONENT_CACHE_FLAG_LOCK, COMPONENT_CACHE_LOCK_EXPIRE); //set lock
						$data[$cacheExpireKey] = COMPONENT_CACHE_FLAG_REGENERATE; //set regeneration flag
					}

					if ($data[$cacheExpireKey] > 0) {
						unset($objs[$cacheKey], $cache[$cacheKey], $cache[$cacheExpireKey], $data[$cacheKey], $data[$cacheExpireKey]);
					}
				}

				$wait  = true;
				$retry = 0;
				//run sql queries for uncached components
				$saveCache = [];

				while ($wait && $retry < COMPONENT_CACHE_MAX_WAIT_RETRY) {
					$wait = false;
					$retry++;

					foreach ($objs as $key => $objects) {
						$cacheExpireKey =  $key . '_expire';

						//check lock
						if ((! isset($data[$cacheExpireKey]) || ! ($data[$cacheExpireKey])) ||
							! isset($data[$key]) ||
							$data[$cacheExpireKey] == COMPONENT_CACHE_FLAG_REGENERATE) {
							//lock set by this script, regenerate content
							$id      = key($objects);

							$results = $objects[$id]->results();

							if ($results !== null) {
								$saveCache[$key]            = $results;
								$saveCache[$cacheExpireKey] = $_SERVER['REQUEST_TIME'] + $objects[$id]->cacheExpire;
							}

							if (isset($results['404']) && $results['404'] == true) {
								$notFound404 = true;
							}

							$data[$cacheExpireKey] = 0;

							foreach ($objects as $index => $instance) {
								$results['_instance'] = $instance;
								$component            = $instance->component;
								$component            = str_replace('-', '_', $component);
								$comp                 = &$view->_component[$component];
								$comp[$index]         = $results;
							}
						} else {
							if ($data[$cacheExpireKey] == COMPONENT_CACHE_FLAG_LOCK) {
								//error_log("wait for $cacheExpireKey");
								//item is locked, some other script is generating content
								$wait = true;
							}
						}
					}

					if ($wait) {
						error_log('wait cache ' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'] . print_r($cache,1));
						//get
						@sleep(COMPONENT_CACHE_WAIT);
						$data = $cacheDriver->getMulti($namespace, $cache);
					}
				}

				if ($retry >= COMPONENT_CACHE_MAX_WAIT_RETRY) {
					error_log('error:CACHE max retry reached for ' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI']);
				}
			}

			if (! empty($saveCache)) {
				$cacheDriver->setMulti($namespace, $saveCache, /*$_SERVER['REQUEST_TIME'] + */COMPONENT_CACHE_EXPIRE * 3600, SITE_ID);
			}
		}

		//call request for each component

		foreach ($this->components as $component => $instances) {
			foreach ($instances as $index => $options) {
				$component = str_replace('-', '_', $component);

				if (isset($view->_component[$component])) {
					$comp      = &$view->_component[$component];
					$results   = &$comp[$index];
					$object    = $results['_instance'] ?? false;

					if ($object && method_exists($object, 'request')) {
						$object->request($results, $index);
					}
				}
			}
		}

		unset($data, $cache);
		$this->components = NULL;

		if ($notFound404) {
			\Vvveb\System\Core\FrontController::notFound(false);
		}
	}

	/*	static  function isLoaded($component)
	{
	return isset($this->queue[$component]);
	}
	*/
	function results() {
	}

	function generateRequiredComponents() {
		//get components from html page
		$document                      = new \DomDocument();
		$document->preserveWhiteSpace  = false;
		$document->recover             = true;
		$document->strictErrorChecking = false;
		$document->formatOutput        = false;
		$document->resolveExternals    = false;
		$document->validateOnParse     = false;
		$document->xmlStandalone       = true;

		$view = view::getInstance();
		libxml_use_internal_errors(true);
		$this->documentType = $view->getDocumentType();

		if ($this->content) {
			if ($this->documentType == 'html') {
				@$document->loadHTML($this->content);
			} else {
				@$document->loadXML($this->content);
			}
		} else {
			$view               = $this->view;
			$template           = $view->template();
			$extension          = strtolower(trim(substr($template, -4), '.'));
			$this->documentType = $extension;

			if ($template[0] == '/') {
			} else {
				if (strpos($template, 'plugins/') === 0) {
					$template   = str_replace('plugins/', '', $template);
					$p          = strpos($template, '/');
					$pluginName = substr($template, 0, $p);
					$nameSpace  = substr($template, $p + 1);
					$app        = '';

					if ($this->app != 'app') {
						$app = $this->app . DS;
					}
					$template = DIR_PLUGINS . $pluginName . DS . 'public' . DS . $app . $nameSpace;
				} else {
					$template = $view->getTemplatePath() . $template;
				}
			}

			if ($this->documentType == 'html') {
				@$document->loadHTMLFile($template,
					LIBXML_NOWARNING | LIBXML_NOERROR);
			} else {
				$content = file_get_contents($template);

				if ($this->documentType == 'json') {
					//remove json comments from line start
					$content = removeJsonComments($content);
					$json    = json_decode($content, true);
					$json    = \Vvveb\prepareJson($json);
					$xml     = \Vvveb\array2xml($json);
					@$document->loadXML($xml);
				} else {
					@$document->loadXML($content,
						LIBXML_NOWARNING | LIBXML_NOERROR);
				}
			}
		}

		$xpath = new \DOMXpath($document);
		$i     = 0;

		//include froms in case any component_ is included
		while (($elements = $xpath->query('//*[ @data-v-copy-from or @data-v-save-global ]')) && $elements->length && $i++ < 2) {
			$fromDocument                      = new \DomDocument();
			$fromDocument->preserveWhiteSpace  = false;
			$fromDocument->recover             = true;
			$fromDocument->strictErrorChecking = false;
			$fromDocument->formatOutput        = false;
			$fromDocument->resolveExternals    = false;
			$fromDocument->validateOnParse     = false;
			$fromDocument->xmlStandalone       = true;

			foreach ($elements as $element) {
				$attribute = $element->getAttribute('data-v-copy-from') ?: $element->getAttribute('data-v-save-global');
				$element->removeAttribute('data-v-copy-from');
				$element->removeAttribute('data-v-save-global');

				if (preg_match('/([^\,]+)\,([^$,]+)/', $attribute , $from)) {
					$file     = html_entity_decode(trim($from[1]));
					$selector = html_entity_decode(trim($from[2]));

					if ($this->documentType == 'html') {
						$fromDocument->loadHTMLFile($view->getTemplatePath() . $file);
					} else {
						$fromDocument->loadXML($view->getTemplatePath() . $file);
					}

					$fromXpath = new \DOMXpath($fromDocument);

					$fromElements = $fromXpath->query(\Vvveb\cssToXpath($selector));

					$count  = 0;
					$parent = $element->parentNode;

					foreach ($fromElements as $externalNode) {
						$importedNode = $document->importNode($externalNode, true);

						if ($parent) {
							if ($count) {
								$parent->appendChild($importedNode);
							} else {
								$parent->replaceChild($importedNode, $element);
							}
							$element = $importedNode;
							//$parent = $element->parentNode;
							$count++;
						}
					}
				}
			}
		}

		//search for elements that have an attribute starting with data-v-component-
		$elements = $xpath->query('//*[@*[starts-with(name(), "data-v-component-")]]');

		foreach ($elements as $element) {
			$component = '';
			$opts      = [];

			foreach ($element->attributes as $attr) {
				$nodeName = $attr->nodeName;

				if (strpos($nodeName, 'data-v-component-') === 0) {
					$component = str_replace('data-v-component-', '', $nodeName);
					//$classes = explode(' ', trim($attr->nodeValue));
				} else {
					if (strpos($nodeName, 'data-v-') === 0) {
						$option        = str_replace('data-v-', '', $nodeName);
						$opts[$option] = $attr->nodeValue;
					}
				}
			}
			//get all classes
			//search for options
			$options = null;
			//validate options
			$validOptions   = [];

			if (strpos($component, 'plugin') === 0) {
				$template   = str_replace('plugin', '', $component);
				$p          = strrpos($template, '-');
				$pluginName = substr($template, 1, $p - 1);
				$nameSpace  = substr($template, $p + 1);
				$app        = '';

				if ($this->app != 'app') {
					$app = $this->app . DS;
				}
				$pluginClassName = dashesToCamelCase($pluginName);
				$componentClass  = "Vvveb\Plugins\\$pluginClassName\Component\\$nameSpace";
				$file            = DIR_PLUGINS . "$pluginName/component/" . str_replace('-', '/', $nameSpace) . '.php';
			} else {
				$componentClass = '\Vvveb\Component\\' . ucfirst(str_replace('-', '\\', $component));
				$file           = DIR_ROOT . $this->app . DS . 'component/' . str_replace('-', '/', $component) . '.php';
			}

			if (file_exists($file)) {
				include_once $file;
				//$componentClass = new $componentClass;
				//do not add design only components
				if (isset($componentClass::$designOnly) && $componentClass::$designOnly == true) {
					continue;
				}
				$validOptions = array_keys($componentClass::$defaultOptions);
			} else {
				if (defined('DEBUG') && \DEBUG) {
					error_log("Component does not exist $componentClass => $file");
					//die("Component does not exist $componentClass => $file");
				}

				continue;
			}

			//save options
			foreach ($opts as $name => $option) {
				if (in_array($name, $validOptions) && isset($option) !== false) {
					if ((isset($option[0]) && ($option[0] == '{' || $option[0] == '[')) || (strpos($option, ',') !== false)) {
						$options[$name] = json_decode($option, 1);
					} else {
						$options[$name] = $option;
					}
				}
			}

			$options['_hash']         = md5($component . serialize($options));
			$components[$component][] = $options;
		}

		if (isset($components)) {
			$this->components = $components;
		}
		//get fields for component
		//load components and feed fields
	}

	function saveTemplateComponents() {
		$php = var_export($this->components, true);
		$php = preg_replace('/\s+/', ' ', $php);
		//repeating end lines
		$php = preg_replace('/\n+/', '', $php);

		return file_put_contents($this->componentsFile, '<?php $components=' . $php . ';');
	}

	function loadTemplateComponents() {
		include_once $this->componentsFile;

		if (isset($components)) {
			$this->components = $components;
		}
		//keep only requested service
		if (isset($_GET['component_ajax'])) {
		}

		return true;
	}
}
