<?php

namespace FaZeBook\Page;

require_once(__DIR__.'/../../Application/Page/PageInterface.php');

use Application\Page\PageInterface;
use FaZeBook\Data;
use FaZeBook\Session;

class Search implements PageInterface {

    public function getId()
    {
        return "searchbar";
    }

    public function hasNavigationItem()
    {
        return false;
    }

    public function getTitle()
    {
        return 'Suche';
    }

    public function getViewScript()
    {
        return __DIR__.'/../../../view/app/search_results.php';
    }

    public function getViewVariables()
    {
        $result['search_res'] = $this->searchResults();
        $result['pageTarget'] = "viewprofile";

        if (isset($_POST['pageTarget'])) {
            $result['pageTarget'] = htmlspecialchars($_POST['pageTarget']);
        }

        return $result;
    }

    //--------------- CLASS HELPER FUNCTIONS ---------------//

    private function searchResults ()
    {
    	if(isset($_POST["input"]) && $_POST['input'] != '')
        {
	    $searchTerm = $_POST["input"];

	    $users = Data::getInstance()->listUsers();
	    $users = $this->sortByLevenshtein($searchTerm, $users);

	    return array_values($users);

        } else {

           echo "<p>Bitte einen Suchbegriff eingeben!</p>";

        }

        return [];
    }

    /*
    Credits to Mr Wladimir lossifowitsch Lewenstein, born 1935.
    The russian Mathematician who knew his shit about making dank
    algorithms. He received the Richard-W.-Hamming-Medal for his
    groundbreaking work
    */

    private function sortByLevenshtein ($input, $users)
    {
    	if($users == []){

            return [];

	} else {

	    $lev_array = [];

	    foreach ($users as $user)
	    {
	    	$userSubStrings = explode(" ", $user->getFullName());
		$inputSubStrings = explode(" ", $input);

		/*
		Initialization of sorting parameters
		*/

		$pos = false;
		$lev = 0;
		$lev_min = 255;

		//Case insensitive search

		foreach ($userSubStrings as $u)
		{
		    $u_low = strtolower($u);
		    $lev_tmp = 255;

		    foreach ($inputSubStrings as $i)
		    {
		        $i_low = strtolower($i);

		    	if(($pos === false) && ($i !== "")) $pos = strpos($u_low, $i_low);
		    	$lev_tmp = min($lev_tmp, levenshtein($i_low,$u_low));
		    }

		    $lev += $lev_tmp;
		    $lev_min = min($lev_min, $lev);
		}

	        /*
	        Create associative array to store users
	        in array that share a levenshtein distance.
	        Later used to sort the array by key.
	        */

		if($pos !== false)
		{
		    $lev_array[$lev][] = $user;

		} elseif($lev_min < 3) {

		    $lev_array[$lev + 255][] = $user;
		}
            }
	}

	ksort($lev_array);

	$res = [];

	foreach($lev_array as $pos_array)
	{
	    foreach($pos_array as $a)
	    {
	        $res[] = $a;
	    }
	}

	return $res;
    }

}