<?php
/**
 * Zend Framework (http://framework.zend.com/)
 *
 * @link      http://github.com/zendframework/zf2 for the canonical source repository
 * @copyright Copyright (c) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
 * @license   http://framework.zend.com/license/new-bsd New BSD License
 */
namespace Zend\Console\Prompt;

use Zend\Console\Exception;
use Zend\Stdlib\ArrayUtils;

final class Checkbox extends AbstractPrompt
{
    /**
     * @var string
     */
    private $promptText;

    /**
     * @var bool
     */
    private $ignoreCase;

    /**
     * @var array|Transversable
     */
    private $options;

    /**
     * Checked options
     * @var array
     */
    private $checkedOptions = [];

    /**
     * If the response should be echoed to the console or not
     * @var bool
     */
    private $echo;

    /**
     * Ask the user to select any number of pre-defined options
     *
     * @param string              $promptText The prompt text to display in console
     * @param array|Transversable $options    Allowed options
     * @param bool                $echo       True to display selected option?
     */
    public function __construct(
        $promptText = 'Please select one option (Enter to finish) ',
        $options = [],
        $ignoreCase = true,
        $echo = false
    ) {
        $this->promptText = (string) $promptText;

        $this->setOptions($options);

        $this->echo = (bool) $echo;

        $this->ignoreCase = (bool) $ignoreCase;
    }

    /**
     * Show a list of options and prompt the user to select any number of them.
     *
     * @return array Checked options
     */
    public function show()
    {
        $this->checkedOptions = [];
        $mask = $this->prepareMask();

        do {
            $this->showAvailableOptions();

            $response = $this->readOption($mask);

            if ($this->echo) {
                $this->showResponse($response);
            }

            $this->checkOrUncheckOption($response);
        } while ($response != "\r" && $response != "\n");

        $this->lastResponse = $this->checkedOptions;

        return $this->checkedOptions;
    }

    /**
     * Shows the selected option to the screen
     * @param string $response
     */
    private function showResponse($response)
    {
        $console = $this->getConsole();
        if (isset($this->options[$response])) {
            $console->writeLine($this->options[$response]);
        } else {
            $console->writeLine();
        }
    }

    /**
     * Check or uncheck an option
     *
     * @param string $response
     */
    private function checkOrUncheckOption($response)
    {
        if ($response != "\r" && $response != "\n" && isset($this->options[$response])) {
            $pos = array_search($this->options[$response], $this->checkedOptions);
            if ($pos === false) {
                $this->checkedOptions[] = $this->options[$response];
            } else {
                array_splice($this->checkedOptions, $pos, 1);
            }
        }
    }

    /**
     * Generates a mask to to be used by the readChar method.
     *
     * @return string
     */
    private function prepareMask()
    {
        $mask = implode("", array_keys($this->options)) . "\r\n";

        /**
         * Normalize the mask if case is irrelevant
         */
        if (! $this->ignoreCase) {
            return $mask;
        }

        $mask = implode("", array_unique(str_split(strtolower($mask) . strtoupper($mask))));

        return $mask;
    }

    /**
     * Reads a char from console.
     *
     * @param  string $mask
     * @return string
     */
    private function readOption($mask)
    {
        /**
         * Read char from console
         */

        return $this->getConsole()->readChar($mask);
    }

    /**
     * Shows the available options with checked and unchecked states
     */
    private function showAvailableOptions()
    {
        $console = $this->getConsole();
        $console->writeLine($this->promptText);
        foreach ($this->options as $k => $v) {
            $console->writeLine('  ' . $k . ') ' . (in_array($v, $this->checkedOptions) ? '[X] ' : '[ ] ') . $v);
        }
    }

    /**
     * Set allowed options
     *
     * @param  array|\Traversable                 $options
     * @throws Exception\InvalidArgumentException
     */
    private function setOptions($options)
    {
        $options = ArrayUtils::iteratorToArray($options);

        if (empty($options)) {
            throw new Exception\InvalidArgumentException('Please, specify at least one option');
        }

        $this->options = $options;
    }
}