<?php

namespace Core;

class Router {
    protected $routes = array();

    public function __construct(array $routes = null) {
        if (is_array($routes)) {
            $this->setRoutes($routes);
        }
    }

    public function setRoutes($routes) {
        foreach ($routes as $k => $v) {
            $route = $k;
            $controller = $v['controller'];
            $action = isset($v['action']) ? $v['action'] : null;
            $this->addRoute($route, $controller, $action);
        }
    }

    public function addRoute($route, $controller, $action = null) {
        list($method, $route) = $this->parseRoute($route);
        $pattern = $this->compileRoute($route);
        $this->routes[$pattern] = array($method, $controller, $action);
    }

    protected function parseRoute($route) {
        if ($route[0] == '/') {
            $method = null;
        }
        else {
            $parts = explode(' ',$route);
            $method = $parts[0];
            $route = $parts[1];
        }
        return array($method, $route);
    }

    protected function compileRoute($route) {
        $replacements = array(
            'num' => '\d+',
            'id' => '[1-9]\d*',
            'str' => '\w+',
            'any' => '.+',
        );
        $parts = preg_split('/\<(.*)\>/', $route, -1, PREG_SPLIT_DELIM_CAPTURE);
        $i = 0;
        $count = count($parts);
        $pattern = '|^';
        for (;;) {
            $pattern .= preg_quote($parts[$i++]);
            if ($i == $count) {
                break;
            }
            $placeholder = $parts[$i++];
            if (!array_key_exists($placeholder, $replacements)) {
                throw new \Exception("Unknown placeholder <$placeholder> in route \"$route\"");
            }
            $pattern .= "({$replacements[$placeholder]})";
        }
        $pattern .= '$|';
        return $pattern;
    }

    public function serve($path) {
        foreach ($this->routes as $pattern => $route) {
            list($method, $controller, $action) = $route;
            if (preg_match($pattern, $path, $matches) &&
                ($method == null || $method == $_SERVER['REQUEST_METHOD'])) {
                $instance = new $controller();
                $action = is_null($action) ? 'index' : $action;
                return call_user_func_array(array($instance, $action), array_slice($matches, 1));
            }
        }
        throw new NotFound();
    }
}