<?php

// phpcs:disable PSR1.Classes.ClassDeclaration.MissingNamespace
// phpcs:disable PSR1.Files.SideEffects
defined('SYSPATH') or die('No direct access allowed.');
// phpcs:enable PSR1.Files.SideEffects
// phpcs:disable Squiz.Classes.ValidClassName.NotCamelCaps

/**
 * Captcha library.
 *
 * $Id: Captcha.php 4072 2009-03-13 17:20:38Z jheathco $
 *
 * @package    Captcha
 * @author     Kohana Team
 * @copyright  (c) 2007-2008 Kohana Team
 * @license    http://kohanaphp.com/license.html
 */
class Captcha_Core
{
    // Captcha singleton
    protected static $instance;

    // Style-dependent Captcha driver
    protected $driver;

    // Config values
    public static $config = array
    (
        'style'      => 'basic',
        'width'      => 150,
        'height'     => 50,
        'complexity' => 4,
        'background' => '',
        'fontpath'   => '',
        'fonts'      => array(),
        'promote'    => false,
    );

    /**
     * Singleton instance of Captcha.
     *
     * @return  object
     */
    public static function instance()
    {
        // Create the instance if it does not exist
        empty(Captcha::$instance) and new Captcha();

        return Captcha::$instance;
    }

    /**
     * Constructs and returns a new Captcha object.
     *
     * @param   string  config group name
     * @return  object
     */
    public static function factory($group = null)
    {
        return new Captcha($group);
    }

    /**
     * Constructs a new Captcha object.
     *
     * @throws  Kohana_Exception
     * @param   string  config group name
     * @return  void
     */
    public function __construct($group = null)
    {
        // Create a singleton instance once
        empty(Captcha::$instance) and Captcha::$instance = $this;

        // No config group name given
        if (! is_string($group)) {
            $group = 'default';
        }

        // Load and validate config group
        if (! is_array($config = Kohana::config('captcha.' . $group))) {
            throw new Kohana_Exception('captcha.undefined_group', $group);
        }

        // All captcha config groups inherit default config group
        if ($group !== 'default') {
            // Load and validate default config group
            if (! is_array($default = Kohana::config('captcha.default'))) {
                throw new Kohana_Exception('captcha.undefined_group', 'default');
            }

            // Merge config group with default config group
            $config += $default;
        }

        // Assign config values to the object
        foreach ($config as $key => $value) {
            if (array_key_exists($key, Captcha::$config)) {
                Captcha::$config[$key] = $value;
            }
        }

        // Store the config group name as well, so the drivers can access it
        Captcha::$config['group'] = $group;

        // If using a background image, check if it exists
        if (! empty($config['background'])) {
            Captcha::$config['background'] = str_replace('\\', '/', realpath($config['background']));

            if (! is_file(Captcha::$config['background'])) {
                throw new Kohana_Exception('captcha.file_not_found', Captcha::$config['background']);
            }
        }

        // If using any fonts, check if they exist
        if (! empty($config['fonts'])) {
            Captcha::$config['fontpath'] = str_replace('\\', '/', realpath($config['fontpath'])) . '/';

            foreach ($config['fonts'] as $font) {
                if (! is_file(Captcha::$config['fontpath'] . $font)) {
                    throw new Kohana_Exception('captcha.file_not_found', Captcha::$config['fontpath'] . $font);
                }
            }
        }

        // Set driver name
        $driver = 'Captcha_' . ucfirst($config['style']) . '_Driver';

        // Load the driver
        if (! Kohana::auto_load($driver)) {
            throw new Kohana_Exception('core.driver_not_found', $config['style'], get_class($this));
        }

        // Initialize the driver
        $this->driver = new $driver();

        // Validate the driver
        if (! ($this->driver instanceof Captcha_Driver)) {
            throw new Kohana_Exception('core.driver_implements', $config['style'], get_class($this), 'Captcha_Driver');
        }

        Kohana::log('debug', 'Captcha Library initialized');
    }

    /**
     * Validates a Captcha response and updates response counter.
     *
     * @param   string   captcha response
     * @return  boolean
     */
    public static function valid($response)
    {
        // Maximum one count per page load
        static $counted;

        // User has been promoted, always TRUE and don't count anymore
        if (Captcha::instance()->promoted()) {
            return true;
        }

        // Challenge result
        $result = (bool) Captcha::instance()->driver->valid($response);

        // Increment response counter
        if ($counted !== true) {
            $counted = true;

            // Valid response
            if ($result === true) {
                Captcha::instance()->valid_count(Session::instance()->get('captcha_valid_count') + 1);
            } else {
            // Invalid response
                Captcha::instance()->invalid_count(Session::instance()->get('captcha_invalid_count') + 1);
            }
        }

        return $result;
    }

    /**
     * Gets or sets the number of valid Captcha responses for this session.
     *
     * @param   integer  new counter value
     * @param   boolean  trigger invalid counter (for internal use only)
     * @return  integer  counter value
     */
    public function valid_count($new_count = null, $invalid = false)
    {
        // Pick the right session to use
        $session = ($invalid === true) ? 'captcha_invalid_count' : 'captcha_valid_count';

        // Update counter
        if ($new_count !== null) {
            $new_count = (int) $new_count;

            // Reset counter = delete session
            if ($new_count < 1) {
                Session::instance()->delete($session);
            } else {
            // Set counter to new value
                Session::instance()->set($session, (int) $new_count);
            }

            // Return new count
            return (int) $new_count;
        }

        // Return current count
        return (int) Session::instance()->get($session);
    }

    /**
     * Gets or sets the number of invalid Captcha responses for this session.
     *
     * @param   integer  new counter value
     * @return  integer  counter value
     */
    public function invalid_count($new_count = null)
    {
        return $this->valid_count($new_count, true);
    }

    /**
     * Resets the Captcha response counters and removes the count sessions.
     *
     * @return  void
     */
    public function reset_count()
    {
        $this->valid_count(0);
        $this->valid_count(0, true);
    }

    /**
     * Checks whether user has been promoted after having given enough valid responses.
     *
     * @param   integer  valid response count threshold
     * @return  boolean
     */
    public function promoted($threshold = null)
    {
        // Promotion has been disabled
        if (Captcha::$config['promote'] === false) {
            return false;
        }

        // Use the config threshold
        if ($threshold === null) {
            $threshold = Captcha::$config['promote'];
        }

        // Compare the valid response count to the threshold
        return ($this->valid_count() >= $threshold);
    }

    /**
     * Returns or outputs the Captcha challenge.
     *
     * @param   boolean  TRUE to output html, e.g. <img src="#" />
     * @return  mixed    html string or void
     */
    public function render($html = true)
    {
        return $this->driver->render($html);
    }

    /**
     * Magically outputs the Captcha challenge.
     *
     * @return  mixed
     */
    public function __toString()
    {
        return $this->render();
    }
}
// End Captcha Class