<?php
    /**
     * This file is part of klj613's micro MVC framework made out of boredom.
     * 
     * (c) Kristian Lewis Jones <klj613@kristianlewisjones.com>
     * 
     * For the full copyright and license information, please view the LICENSE
     * file that was distributed with this source code.
     */
    
    /**
     * Used to render templates.
     * 
     * @author Kristian Lewis Jones <klj613@kristianlewisjones.com>
     */
    class Router
    {
        private $routing;
        
        public $uri;
        public $routeId;
        
        /**
         * Constructor.
         * 
         * @param array $routing The routing config.
         */
        public function __construct($routing)
        {
            $this->routing = $routing;
        }
        
        /**
         * Initiates the handling of a specific URI.
         * 
         * @param string $uri The URI to handle.
         */
        public function handleRequest($uri)
        {
            $this->uri = $uri;
            
            $routeId = $this->matchRouting($uri);
            
            $this->routeId = $routeId;
            
            $params = $this->getParams($uri, $routeId);
            
            list($class, $method) = $this->routing[$routeId][1];
            $realClass = $class . 'Controller';

            $instance = DIFactory::getController($realClass);
            
            call_user_func_array(array($instance, $method), $params);
        }
        
        /**
         * Get the routing ID that belongs to a specific URI.
         * 
         * @param string $uri The URI to match.
         *
         * @throws Exception
         */
        public function matchRouting($uri)
        {
            foreach ($this->routing as $rule)
            {
                $pattern = $rule[0];
                $regex = '#' . preg_replace('#{([^/]+)}#', '([a-zA-Z0-9-]+)', $pattern) . '#';
                if (preg_match($regex, $uri))
                {
                    return key($this->routing);
                }
                next($this->routing);
            }
            throw new Exception("No Routing Found for `$uri`");
        }
        
        /**
         * Get the parameters off a URI.
         * 
         * @param string $uri
         * @param string $routeId
         *
         * @throws Exception
         * 
         * @return array The parameters of the URI.
         */
        public function getParams($uri, $routeId)
        {
            $pattern = $this->routing[$routeId][0];
            $regex = '#{([^/]+)}#';
            
            preg_match_all($regex, $pattern, $matchedKeys);
            
            $derivedRegex = preg_replace($regex, '([^/]+)', $pattern);
            preg_match_all('#' . $derivedRegex . '#', $uri, $matchedValues);
            
            $structure = $this->getParamsStructure($routeId);
            
            if (count($matchedKeys[0]) == 0)
            {
                $count = 0;    
            }
            else
            {
                $count = count($matchedKeys[1]);    
            }
            $realCouunt = count($structure);
            if ($count != $realCouunt)
            {
                throw new Exception("Parameter count on the Routing Pattern doesn't match the controller");
            }
            
            $params = array();
            for ($i = 0; $i < $count; $i++)
            {
                $key = $matchedKeys[1][$i];
                if (in_array($key, $structure) == false)
                {
                    throw new Exception("Parameter `$key` doesn't exist on the controller");
                }
                $value = $matchedValues[$i + 1][0];
                $params[$key] = $value;
            }
            
            return $params;        
        }
                
        /**
         * Get the parameter structure off a controller method.
         * 
         * @param string $routeId
         * 
         * @return array The parameter structure.
         */
        public function getParamsStructure($routeId)
        {
            list($controllerClass, $controllerMethod) = $this->routing[$routeId][1];
            $controllerRealClass = $controllerClass . 'Controller';

            $reflectionClass = new ReflectionClass($controllerRealClass);
            $reflectionMethod = $reflectionClass->getMethod($controllerMethod);
            $refParams = $reflectionMethod->getParameters();
            
            $realParams = array();
            foreach ($refParams as $refParam)
            {
                $realParams[] = $refParam->name;
            }
            
            return $realParams;
        }
        
        /**
         * Generates URI's that are absolute to the domain.
         * 
         * @param string $routeId
         * @param array $params The parameters to insert into the URI.
         *
         * @throws Exception
         * 
         * @return string The URI.
         */
        public function generate($routeId, $params = array())
        {
            if (isset($this->routing[$routeId]) == false)
            {
                throw new Exception("Route `$routeId` doesn't exist.");
            }
            
            $structure = $this->getParamsStructure($routeId);
            
            $count = count($params);
            $realCouunt = count($structure);
            if ($count != $realCouunt)
            {
                throw new Exception("Parameter count on the Routing Pattern doesn't match the controller");
            }
            
            $uri = $this->routing[$routeId][0];            
            foreach ($params as $key => $value)
            {
                if (in_array($key, $structure) == false)
                {
                    throw new Exception("Parameter `$key` doesn't exist on the controller");
                }
                $uri = str_replace('{' . $key . '}', $value, $uri);
            }
                
            $baseUri = dirname($_SERVER['SCRIPT_NAME']) . '/';
            
            return $baseUri . $uri;
        }
        
        /**
         * Gets the URI off the Global variables.
         * 
         * @static
         * 
         * @return string
         */
        public static function getUriFromGlobals()
        {
            return substr($_SERVER['REQUEST_URI'], strlen(dirname($_SERVER['SCRIPT_NAME'])) + 1);
        }
    }
?>