<?php
require_once(__DIR__ . '/BridgeInterface.php');
abstract class BridgeAbstract implements BridgeInterface {

	const NAME = 'Unnamed bridge';
	const URI = '';
	const DESCRIPTION = 'No description provided';
	const MAINTAINER = 'No maintainer';
	const PARAMETERS = array();

	public $useProxy = true;

	protected $cache;
	protected $items = array();
	protected $inputs = array();
	protected $queriedContext = '';

	protected function returnError($message, $code){
		throw new \HttpException($message, $code);
	}

	protected function returnClientError($message){
		$this->returnError($message, 400);
	}

	protected function returnServerError($message){
		$this->returnError($message, 500);
	}

	/**
	* Return items stored in the bridge
	* @return mixed
	*/
	public function getItems(){
		return $this->items;
	}

	protected function validateTextValue($value, $pattern = null){
		if(!is_null($pattern)){
			$filteredValue = filter_var($value
			, FILTER_VALIDATE_REGEXP
			, array('options' => array(
					'regexp' => '/^' . $pattern . '$/'
				))
			);
		} else {
			$filteredValue = filter_var($value);
		}

		if($filteredValue === false)
			return null;

		return $filteredValue;
	}

	protected function validateNumberValue($value){
		$filteredValue = filter_var($value, FILTER_VALIDATE_INT);

		if($filteredValue === false && !empty($value))
			return null;

		return $filteredValue;
	}

	protected function validateCheckboxValue($value){
		$filteredValue = filter_var($value, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE);

		if(is_null($filteredValue))
			return null;

		return $filteredValue;
	}

	protected function validateListValue($value, $expectedValues){
		$filteredValue = filter_var($value);

		if($filteredValue === false)
			return null;

		if(!in_array($filteredValue, $expectedValues)){ // Check sub-values?
			foreach($expectedValues as $subName => $subValue){
				if(is_array($subValue) && in_array($filteredValue, $subValue))
					return $filteredValue;
			}
			return null;
		}

		return $filteredValue;
	}

	protected function validateData(&$data){
		if(!is_array($data))
			return false;

		foreach($data as $name => $value){
			$registered = false;
			foreach(static::PARAMETERS as $context => $set){
				if(array_key_exists($name, $set)){
					$registered = true;
					if(!isset($set[$name]['type'])){
						$set[$name]['type'] = 'text';
					}

					switch($set[$name]['type']){
					case 'number':
						$data[$name] = $this->validateNumberValue($value);
						break;
					case 'checkbox':
						$data[$name] = $this->validateCheckboxValue($value);
						break;
					case 'list':
						$data[$name] = $this->validateListValue($value, $set[$name]['values']);
						break;
					default:
					case 'text':
						if(isset($set[$name]['pattern'])){
							$data[$name] = $this->validateTextValue($value, $set[$name]['pattern']);
						} else {
							$data[$name] = $this->validateTextValue($value);
						}
						break;
					}

					if(is_null($data[$name])){
						echo 'Parameter \'' . $name . '\' is invalid!' . PHP_EOL;
						return false;
					}
				}
			}

			if(!$registered)
				return false;
		}

		return true;
	}

	protected function setInputs(array $inputs, $queriedContext){
		// Import and assign all inputs to their context
		foreach($inputs as $name => $value){
			foreach(static::PARAMETERS as $context => $set){
				if(array_key_exists($name, static::PARAMETERS[$context])){
					$this->inputs[$context][$name]['value'] = $value;
				}
			}
		}

		// Apply default values to missing data
		$contexts = array($queriedContext);
		if(array_key_exists('global', static::PARAMETERS)){
			$contexts[] = 'global';
		}

		foreach($contexts as $context){
			foreach(static::PARAMETERS[$context] as $name => $properties){
				if(isset($this->inputs[$context][$name]['value'])){
					continue;
				}

				$type = isset($properties['type']) ? $properties['type'] : 'text';

				switch($type){
				case 'checkbox':
					if(!isset($properties['defaultValue'])){
						$this->inputs[$context][$name]['value'] = false;
					} else {
						$this->inputs[$context][$name]['value'] = $properties['defaultValue'];
					}
					break;
				case 'list':
					if(!isset($properties['defaultValue'])){
						$firstItem = reset($properties['values']);
						if(is_array($firstItem)){
							$firstItem = reset($firstItem);
						}
						$this->inputs[$context][$name]['value'] = $firstItem;
					} else {
						$this->inputs[$context][$name]['value'] = $properties['defaultValue'];
					}
					break;
				default:
					if(isset($properties['defaultValue'])){
						$this->inputs[$context][$name]['value'] = $properties['defaultValue'];
					}
					break;
				}
			}
		}

		// Copy global parameter values to the guessed context
		if(array_key_exists('global', static::PARAMETERS)){
			foreach(static::PARAMETERS['global'] as $name => $properties){
				if(isset($inputs[$name])){
					$value = $inputs[$name];
				} elseif (isset($properties['value'])){
					$value = $properties['value'];
				} else {
					continue;
				}
				$this->inputs[$queriedContext][$name]['value'] = $value;
			}
		}

		// Only keep guessed context parameters values
		if(isset($this->inputs[$queriedContext])){
			$this->inputs = array($queriedContext => $this->inputs[$queriedContext]);
		} else {
			$this->inputs = array();
		}
	}

	protected function getQueriedContext(array $inputs){
		$queriedContexts = array();
		foreach(static::PARAMETERS as $context => $set){
			$queriedContexts[$context] = null;
			foreach($set as $id => $properties){
				if(isset($inputs[$id]) && !empty($inputs[$id])){
					$queriedContexts[$context] = true;
				} elseif(isset($properties['required'])
				&& $properties['required'] === true){
					$queriedContexts[$context] = false;
					break;
				}
			}
		}

		if(array_key_exists('global', static::PARAMETERS)
		&& $queriedContexts['global'] === false){
			return null;
		}
		unset($queriedContexts['global']);

		switch(array_sum($queriedContexts)){
		case 0:
			foreach($queriedContexts as $context => $queried){
				if (is_null($queried)){
					return $context;
				}
			}
			return null;
		case 1: return array_search(true, $queriedContexts);
		default: return false;
		}
	}

	/**
	* Defined datas with parameters depending choose bridge
	* Note : you can define a cache with "setCache"
	* @param array array with expected bridge paramters
	*/
	public function setDatas(array $inputs){
		if(!is_null($this->cache)){
			$this->cache->prepare($inputs);
			$time = $this->cache->getTime();
			if($time !== false && (time() - $this->getCacheDuration() < $time)){
				$this->items = $this->cache->loadData();
				return;
			}
		}

		if(empty(static::PARAMETERS)){
			if(!empty($inputs)){
				$this->returnClientError('Invalid parameters value(s)');
			}

			$this->collectData();
			if(!is_null($this->cache)){
				$this->cache->saveData($this->getItems());
			}
			return;
		}

		if(!$this->validateData($inputs)){
			$this->returnClientError('Invalid parameters value(s)');
		}

		// Guess the paramter context from input data
		$this->queriedContext = $this->getQueriedContext($inputs);
		if(is_null($this->queriedContext)){
			$this->returnClientError('Required parameter(s) missing');
		} elseif($this->queriedContext === false){
			$this->returnClientError('Mixed context parameters');
		}

		$this->setInputs($inputs, $this->queriedContext);

		$this->collectData();

		if(!is_null($this->cache)){
			$this->cache->saveData($this->getItems());
		}
	}

	function getInput($input){
		if(!isset($this->inputs[$this->queriedContext][$input]['value'])){
			return null;
		}
		return $this->inputs[$this->queriedContext][$input]['value'];
	}

	public function getName(){
		return static::NAME;
	}

	public function getURI(){
		return static::URI;
	}

	public function getCacheDuration(){
		return 3600;
	}

	public function setCache(\CacheAbstract $cache){
		$this->cache = $cache;
	}

	public function debugMessage($text){
		if(!file_exists('DEBUG')) {
			return;
		}

		$backtrace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 3);
		$calling = $backtrace[2];
		$message = $calling['file'] . ':'
		. $calling['line'] . ' class '
		. get_class($this) . '->'
		. $calling['function'] . ' - '
		. $text;

		error_log($message);
	}

	protected function getContents($url
	, $use_include_path = false
	, $context = null
	, $offset = 0
	, $maxlen = null){
		$contextOptions = array(
			'http' => array(
				'user_agent' => ini_get('user_agent')
			)
		);

		if(defined('PROXY_URL') && $this->useProxy){
			$contextOptions['http']['proxy'] = PROXY_URL;
			$contextOptions['http']['request_fulluri'] = true;

			if(is_null($context)){
				$context = stream_context_create($contextOptions);
			} else {
				$prevContext = $context;
				if(!stream_context_set_option($context, $contextOptions)){
					$context = $prevContext;
				}
			}
		}

		if(is_null($maxlen)){
			$content = @file_get_contents($url, $use_include_path, $context, $offset);
		} else {
			$content = @file_get_contents($url, $use_include_path, $context, $offset, $maxlen);
		}

		if($content === false)
			$this->debugMessage('Cant\'t download ' . $url);

		// handle compressed data
		foreach($http_response_header as $header){
			if(stristr($header, 'content-encoding')){
				switch(true){
					case stristr($header, 'gzip'):
						$content = gzinflate(substr($content, 10, -8));
						break;
					case stristr($header, 'compress'):
						//TODO
					case stristr($header, 'deflate'):
						//TODO
					case stristr($header, 'brotli'):
						//TODO
						$this->returnServerError($header . '=> Not implemented yet');
						break;
					case stristr($header, 'identity'):
						break;
					default:
						$this->returnServerError($header . '=> Unknown compression');
				}
			}
		}

		return $content;
	}

	protected function getSimpleHTMLDOM($url
	, $use_include_path = false
	, $context = null
	, $offset = 0
	, $maxLen = null
	, $lowercase = true
	, $forceTagsClosed = true
	, $target_charset = DEFAULT_TARGET_CHARSET
	, $stripRN = true
	, $defaultBRText = DEFAULT_BR_TEXT
	, $defaultSpanText = DEFAULT_SPAN_TEXT){
		$content = $this->getContents($url, $use_include_path, $context, $offset, $maxLen);
		return str_get_html($content
		, $lowercase
		, $forceTagsClosed
		, $target_charset
		, $stripRN
		, $defaultBRText
		, $defaultSpanText);
	}

	/**
	 * Maintain locally cached versions of pages to avoid multiple downloads.
	 * @param url url to cache
	 * @param duration duration of the cache file in seconds (default: 24h/86400s)
	 * @return content of the file as string
	 */
	public function getSimpleHTMLDOMCached($url
	, $duration = 86400
	, $use_include_path = false
	, $context = null
	, $offset = 0
	, $maxLen = null
	, $lowercase = true
	, $forceTagsClosed = true
	, $target_charset = DEFAULT_TARGET_CHARSET
	, $stripRN = true
	, $defaultBRText = DEFAULT_BR_TEXT
	, $defaultSpanText = DEFAULT_SPAN_TEXT){
		$this->debugMessage('Caching url ' . $url . ', duration ' . $duration);

		$filepath = __DIR__ . '/../cache/pages/' . sha1($url) . '.cache';
		$this->debugMessage('Cache file ' . $filepath);

		if(file_exists($filepath) && filectime($filepath) < time() - $duration){
			unlink ($filepath);
			$this->debugMessage('Cached file deleted: ' . $filepath);
		}

		if(file_exists($filepath)){
			$this->debugMessage('Loading cached file ' . $filepath);
			touch($filepath);
			$content = file_get_contents($filepath);
		} else {
			$this->debugMessage('Caching ' . $url . ' to ' . $filepath);
			$dir = substr($filepath, 0, strrpos($filepath, '/'));

			if(!is_dir($dir)){
				$this->debugMessage('Creating directory ' . $dir);
				mkdir($dir, 0777, true);
			}

			$content = $this->getContents($url, $use_include_path, $context, $offset, $maxLen);
			if($content !== false){
				file_put_contents($filepath, $content);
			}
		}

		return str_get_html($content
		, $lowercase
		, $forceTagsClosed
		, $target_charset
		, $stripRN
		, $defaultBRText
		, $defaultSpanText);
	}
}