<?php
namespace KIF;

use KIF\Core\Request;
use KIF\Core\Config;
use KIF\String\String;
use KIF\Math\Math;

/**
 * 
 * 路由类
 * @author gaoxiaogang
 *
 */
class Route {
	
	/**
	 * 
	 * Enter description here ...
	 * @var array 格式：array(
	 *     $route_file => array(
	 *     	   'instance'  => (Route),
	 *         'rules'	=> array(
	 *             (string) $rewrite_pattern	=> (array) $rule,
	 *             ... ,
	 *         ),
	 *         'reverse_rules' => array(
	 *             (string)$fingerprint => (string)$rewrite_pattern,
	 *             ... ,
	 *         ),
	 *     ),
	 * );
	 */
	static private $structs;
	
	protected $struct;
	
	# 禁止被外部new
	private function __construct($route_file) {
		if (!file_exists($route_file) || !is_file($route_file)) {
			$route_rules = array();
		} else {
			$route_rules = include($route_file);
		}
		$rules = array();
		$reverse_rules = array();
		if (!$route_rules || !is_array($route_rules)) {
			self::$structs[$route_file]['rules'] = $rules;
			self::$structs[$route_file]['reverse_rules'] = $reverse_rules;
			return;
		}
		
		foreach ($route_rules as $rewrite_pattern	=> $rule) {
			if (!isset($rule['a']) || !$rule['a']) {
				$rule['a'] = 'default';
			}
			$fingerprint = $this->generateFingerprint($rule);
			
			$rules[$rewrite_pattern] = $rule;
			$reverse_rules[$fingerprint] = $rewrite_pattern;
		}
		self::$structs[$route_file]['rules'] = $rules;
		self::$structs[$route_file]['reverse_rules'] = $reverse_rules;
	}
	
	/**
	 * 
	 * 生成指纹，方便反向rewrite时高效查找。
	 * @param array $args
	 * @return string
	 */
	private function generateFingerprint($args) {
		if (!isset($args['a'])) {
			$args['a'] = 'default';
		}
		$arg_eles = array_combine(array_keys($args), array_fill(0, count($args), null));
		if (isset($args['a']))
			$arg_eles['a'] = $args['a'];
		if (isset($args['c']))
			$arg_eles['c'] = $args['c'];
		ksort($arg_eles);
		return Math::md5_16(print_r($arg_eles, true));
	}
	
	/**
	 * 
	 * @return KIF\Route
	 */
	static public function getInstance() {
		$route_file = Config::getInstance()->get('route_file');
		$route_file = realpath($route_file);
		if (!isset(self::$structs[$route_file])) {
			self::$structs[$route_file]['instance'] = new self($route_file);
		}
		self::$structs[$route_file]['instance']->struct = & self::$structs[$route_file];
		return self::$structs[$route_file]['instance'];
	}
	
	/**
	 * 
	 * 实现细节：
	 *     根据当前app的路由配置，查找到指定条目，并将当前path里携带的参数存放进 $_GET和$_REQUEST变量里
	 * 对当前请求路由
	 * 
	 */
	public function rewrite() {
		$path = Request::getInstance()->path();
		$rules = $this->struct['rules'];
		foreach ($rules as $pattern => $rule) {
			$pattern = "#^{$pattern}$#";
			if (preg_match($pattern, $path, $matches)) {
				foreach ($rule as $param	=> $paramVal) {
					if ($paramVal{0} != '$') {
						$_GET[$param] = $paramVal;
						$_REQUEST[$param] = $paramVal;
					} else {
						$match_pos = substr($paramVal, 1);
						if (Verify::naturalNumber($match_pos)) {
							$_GET[$param] = $matches[$match_pos];
							$_REQUEST[$param] = $matches[$match_pos];
						}
					}
					
				}
				break;
			}
		}
	}
	
	/**
	 * 
	 * 获取经过路由后得到的请求参数。目前该方法被 Request::pageUrlTpl使用
	 * @return array 如果没有对应的路由，返回空数组
	 */
	public function getsRouteParams() {
		$route_params = array();
		$path = Request::getInstance()->path();
		$rules = $this->struct['rules'];
		foreach ($rules as $pattern => $rule) {
			$pattern = "#^{$pattern}$#";
			if (preg_match($pattern, $path, $matches)) {
				foreach ($rule as $param	=> $paramVal) {
					if ($paramVal{0} != '$') {
						$route_params[$param] = $paramVal;
					} else {
						$match_pos = substr($paramVal, 1);
						if (Verify::naturalNumber($match_pos)) {
							$route_params[$param] = $matches[$match_pos];
						}
					}
				}
				break;
			}
		}
		
		return $route_params;
	}
	
	/**
	 * 
	 * 反向rewrite。通过 $args 给定的参数，逆向rewrite规则，获取rewrite的url
	 * @param array $args 给定的参数值
	 * @return String
	 */
	public function reverse(array $args) {
		if (!$args) {
			return false;
		}
		if (!isset($args['a'])) {
			$args['a'] = 'default';
		}
		$arg_fingerprint = $this->generateFingerprint($args);
		if (isset($this->struct['reverse_rules'][$arg_fingerprint])) {
			$rewrite_pattern = $this->struct['reverse_rules'][$arg_fingerprint];
			if (strpos($rewrite_pattern, '(') === false) {
				return $rewrite_pattern;
			}
			$rule = $this->struct['rules'][$rewrite_pattern];
			
			$rule = array_filter($rule, function ($tmpV) {
				if ($tmpV{0} != '$') {
					return false;
				}
				return $tmpV;
			});
			
			$match_times = 0;
			$url = preg_replace_callback('#\([^)]+\)#', function ($matches) use (& $match_times, $rule, $args) {
				$match_times++;
				$key = array_search("\${$match_times}", $rule);
				if (!$key) {
					return false;
				}
				if (!isset($args[$key])) {
					return false;
				}
				
				return $args[$key];
			}, $rewrite_pattern);
			
			if (is_null($url)) {//说明发生错误了。
				return String::jointUrl('', $args);
			}
			
			return $url;
		}
		
		return String::jointUrl('', $args);
	}
}