<?php
    $mysql = mysql_connect("localhost", "root", "");
    if(!$mysql) echo "Connection error.";
    $mysql = mysql_select_db("todo");
    if(!$mysql) echo "Error selecting database.";

    $categories = array(1 => "Ogolne", 2 => "NPC");

    function addTodo()
    {
            $query = "insert into todo values(null, $_GET[show], '$_POST[todo]' , 0);";
            mysql_query($query);
    }

    function completeTodo($todo_id)
    {
        $query = "update todo set completed='1' where todo_id='".$todo_id."';";
        $check = mysql_query($query);
    }

    function getTodo($category)
    {
        $query = "Select * from todo where completed='0' and category=".$category.";";
        $rows = mysql_query($query);
        echo "<ul>";
        while($row = mysql_fetch_assoc($rows))
            echo "<li>".$row['description']." <a href='?show=".$row['category']."&complete=".$row['todo_id']."'>Done</a></li>";
        echo "</ul>";
    }

    function getTodoCompleted($category)
    {
        $query = "Select * from todo where completed='1' and category=".$category.";";
        $rows = mysql_query($query);
        echo "<ul>";
        while($row = mysql_fetch_assoc($rows))
            echo "<li>".$row['description']."</li>";
        echo "</ul>";
    }

    foreach($categories as $id => $cat)
        echo "<span style='padding: 5px;'><a href='?show=".$id."'>".$cat."</a></span>";

    if(isset($_GET['complete']))
            completeTodo($_GET['complete']);

    if(isset($_GET['add_todo']))
        addTodo();

    if(isset($_GET['show']))
            getTodo($_GET['show']);

echo '
    <form action="?'.$_SERVER['QUERY_STRING'].'&add_todo" method="post">
        <input type="text" name="todo"/><br>
        <input type="submit" value="Add"/>
    </form>
    ';

    if(isset($_GET['show']))
            getTodoCompleted($_GET['show']);

?>