<?php
namespace gnomephp\mvc\router;


class FromField{
	private $source;
	
	/**
	 * This will be set to true if /? is added to from field to allow additional anonymous vars.
	 * @var boolean
	 */
	private $anonymousVars=false;
	
	/**
	 * Allows to match <Regexp> var
	 * or just var
	 * 
	 * @var string
	 */
	const REGEXP_BITS = '/\/\{(?:<(.*?)>)?([A-Za-z0-9_]+)\}/';
	
	public function __construct($source){
		$this->source = $source;
	}
	
	public function toRegexp(){

		

		// For per bit.
		$regexp = '#'.preg_replace_callback(FromField::REGEXP_BITS, function($matches){
			$r =  '/'.($matches[1] ? '('.$matches[1].')' : '([A-Za-z0-9_-]+)');
			return $r;
		}, $this->source);
		
		// Allow more arguments! /test/2/? also allows /test/2/1/0/-1/
		if (substr($this->source, -2)=='/?'){

			$regexp = substr($regexp, 0, -2);
			
			$this->anonymousVars = true;
			$regexp .= '(.*?)';
			
		}
		
		
		
		$regexp .= '$#';
		return $regexp;
	}
	
	public function reverse($args){
		$url = $this->source;

		
		// Parse {key} to $args[$key] value
		foreach($args as $k => $v){
			$url = preg_replace('/\/\{(?:<.*?>)?('.$k.')\}/', '/'.$v, $url);
		}
		
		// Okay , we got a key set, but what if not all key => value is added....
		// Its ok, we set them to empty value ( no value ).
		$url = preg_replace('/(\{.*?\})/', '', $url);
		
		
		// Return false if this doesn't match with anonymous vars.
		if (!$this->anonymousVars){
			$keys = array_keys($args);
			foreach($keys as $k){
				if (is_int($k))return false;
			}
		}else{
			// Add support for anonymous vars
			$url = substr($url, 0, -2);
			
			foreach($args as $k => $v){
				if (is_int($k)){
					$url .= '/' . $v;
				}
			}
		}
		
		
		
		return new UrlString(substr($url, 1));
	}
	
	
	public function hasAnonymousVars(){
		return $this->moreArgs;
	}
	
	
	public function getVars($values = array()){
		$vars = array();
		preg_match_all(FromField::REGEXP_BITS, $this->source, $vars);
		
		$output = array();
		$key = 1;
		foreach($vars[2] as $k => $var){
			$output[$var] = isset($values[$k+1]) ? $values[$k+1] : null;
			$key++;
		}
		
		$anon = null;
		if (isset ($values[$key]) && $values[$key] != ''){
			
			$anon = explode('/', substr($values[$key], 1));
		}
		
		return array('vars' => $output, 'anonymousVars' => $anon);
	}
}