<?php

/**
 * Part of the Joomla Framework Language Package
 *
 * @copyright  Copyright (C) 2005 - 2020 Open Source Matters, Inc. All rights reserved.
 * @license    GNU General Public License version 2 or later; see LICENSE
 */

namespace Joomla\Language;

/**
 * Catalogue of loaded translation strings for a language
 *
 * @since  2.0.0-alpha
 */
class MessageCatalogue
{
    /**
     * A fallback for this catalogue
     *
     * @var    MessageCatalogue
     * @since  2.0.0-alpha
     */
    private $fallbackCatalogue;

    /**
     * The language of the messages in this catalogue
     *
     * @var    string
     * @since  2.0.0-alpha
     */
    private $language;

    /**
     * The messages stored to this catalogue
     *
     * @var    array
     * @since  2.0.0-alpha
     */
    private $messages = [];

    /**
     * MessageCatalogue constructor.
     *
     * @param   string  $language  The language of the messages in this catalogue
     * @param   array   $messages  The messages to seed this catalogue with
     *
     * @since   2.0.0-alpha
     */
    public function __construct(string $language, array $messages = [])
    {
        $this->language = $language;

        $this->addMessages($messages);
    }

    /**
     * Add a message to the catalogue, replacing the key if it already exists
     *
     * @param   string  $key      The key identifying the message
     * @param   string  $message  The message for this key
     *
     * @return  void
     */
    public function addMessage(string $key, string $message): void
    {
        $this->addMessages([$key => $message]);
    }

    /**
     * Add messages to the catalogue, replacing any keys which already exist
     *
     * @param   array  $messages  An associative array containing the messages to add to the catalogue
     *
     * @return  void
     *
     * @since   2.0.0-alpha
     */
    public function addMessages(array $messages): void
    {
        $this->messages = array_replace($this->messages, array_change_key_case($messages, CASE_UPPER));
    }

    /**
     * Check if this catalogue has a message for the given key, ignoring a fallback if defined
     *
     * @param   string  $key  The key to check
     *
     * @return  boolean
     *
     * @since   2.0.0-alpha
     */
    public function definesMessage(string $key): bool
    {
        return isset($this->messages[strtoupper($key)]);
    }

    /**
     * Get the fallback for this catalogue if set
     *
     * @return  MessageCatalogue|null
     *
     * @since   2.0.0-alpha
     */
    public function getFallbackCatalogue(): ?MessageCatalogue
    {
        return $this->fallbackCatalogue;
    }

    /**
     * Get the language for this catalogue
     *
     * @return  string
     *
     * @since   2.0.0-alpha
     */
    public function getLanguage(): string
    {
        return $this->language;
    }

    /**
     * Get the message for a given key
     *
     * @param   string  $key  The key to get the message for
     *
     * @return  string  The message if one is set otherwise the key
     *
     * @since   2.0.0-alpha
     */
    public function getMessage(string $key): string
    {
        if ($this->definesMessage($key)) {
            return $this->messages[strtoupper($key)];
        }

        if ($this->fallbackCatalogue) {
            return $this->fallbackCatalogue->getMessage($key);
        }

        return strtoupper($key);
    }

    /**
     * Fetch the messages stored in this catalogue
     *
     * @return  array
     *
     * @since   2.0.0-alpha
     */
    public function getMessages(): array
    {
        return $this->messages;
    }

    /**
     * Check if the catalogue has a message for the given key
     *
     * @param   string  $key  The key to check
     *
     * @return  boolean
     *
     * @since   2.0.0-alpha
     */
    public function hasMessage(string $key): bool
    {
        if ($this->definesMessage($key)) {
            return true;
        }

        if ($this->fallbackCatalogue) {
            return $this->fallbackCatalogue->hasMessage($key);
        }

        return false;
    }

    /**
     * Merge another catalogue into this one
     *
     * @param   MessageCatalogue  $messageCatalogue  The catalogue to merge
     *
     * @return  void
     *
     * @since   2.0.0-alpha
     * @throws  \LogicException
     */
    public function mergeCatalogue(MessageCatalogue $messageCatalogue): void
    {
        if ($messageCatalogue->getLanguage() !== $this->getLanguage()) {
            throw new \LogicException('Cannot merge a catalogue that does not have the same language code.');
        }

        $this->addMessages($messageCatalogue->getMessages());
    }

    /**
     * Set the fallback for this catalogue
     *
     * @param   MessageCatalogue  $messageCatalogue  The catalogue to use as the fallback
     *
     * @return  void
     *
     * @since   2.0.0-alpha
     */
    public function setFallbackCatalogue(MessageCatalogue $messageCatalogue): void
    {
        $this->fallbackCatalogue = $messageCatalogue;
    }
}