<?php

namespace Todo\Persistence;

class TodoGateway
{
    private $dbh;
    private $hostname;
    private $username;
    private $password;
    private $database;

    public function __construct($database, $username, $password, $hostname)
    {
        $this->database = $database;
        $this->username = $username;
        $this->password = $password;
        $this->hostname = $hostname;
    }

    private function connect()
    {
        if (null !== $this->dbh) {
            return;
        }

        $this->dbh = mysql_connect($this->hostname, $this->username, $this->password);
        if (false === $this->dbh) {
            throw new \RuntimeException('Cannot connect to MySQL server.');
        }

        if (false === mysql_select_db($this->database, $this->dbh)) {
            throw new \RuntimeException('Cannot select database.');
        }
    }

    private function query($query)
    {
        $this->connect();

        $result = mysql_query($query, $this->dbh);
        if (false === $result) {
            throw new \RuntimeException('SQL query execution failed: '.$query);
        }

        return $result;
    }

    private function quote($data)
    {
        $this->connect();

        return mysql_real_escape_string($data, $this->dbh);
    }

    public function deleteTask($id)
    {
        $this->query('DELETE FROM todo WHERE id = '. (int) $id);
        if (!mysql_affected_rows($this->dbh)) {
            throw new \RuntimeException('Unable to delete task #'.$id);
        }
    }

    public function closeTask($id)
    {
        $this->query('UPDATE todo SET is_done = 1 WHERE id = '. (int) $id);
        if (!mysql_affected_rows($this->dbh)) {
            throw new \RuntimeException('Unable to close task #'.$id);
        }
    }

    public function createTask($title)
    {
        if (empty($title)) {
            throw new \InvalidArgumentException('Title must be filled.');
        }

        $this->query(sprintf(
            "INSERT INTO todo (title) VALUES ('%s');",
            $this->quote($title)
        ));

        if (!mysql_affected_rows($this->dbh)) {
            throw new \RuntimeException(sprintf('Unable to create new task "%s".', $title));
        }
    }

    public function countTasks()
    {
        $result = $this->query('SELECT COUNT(*) FROM todo');

        return (int) current(mysql_fetch_row($result));
    }

    public function getTask($id)
    {
        $result = $this->query('SELECT * FROM todo WHERE id = '. (int) $id);

        return mysql_fetch_assoc($result);
    }

    public function getAllTasks()
    {
        $tasks = array();
        $result = $this->query('SELECT * FROM todo');
        while ($todo = mysql_fetch_assoc($result)) {
            $tasks[] = $todo;
        }

        return $tasks;
    }
}