<?php

namespace ipl\I18n;

/**
 * Provide translation helpers backed by {@see StaticTranslator::$instance}
 */
trait Translation
{
    /**
     * The domain to use in methods {@see Translation::translate()} and {@see Translation::translatePlural()}
     *
     * Set this to your desired domain and use both mentioned methods as usual, if you never require the
     * default translation domain. (It's still being used as a fallback if your domain doesn't provide a
     * particular message.)
     *
     * @var ?string
     */
    protected ?string $translationDomain = null;

    /**
     * Translate a message
     *
     * @param string $message
     * @param ?string $context Message context
     *
     * @return string Translated message or original message if no translation is found
     */
    public function translate(string $message, ?string $context = null): string
    {
        return $this->translationDomain === null
            ? StaticTranslator::$instance->translate($message, $context)
            : StaticTranslator::$instance->translateInDomain($this->translationDomain, $message, $context);
    }

    /**
     * Translate a message in the given domain
     *
     * If no translation is found in the specified domain, the translation is also searched for in the default domain.
     *
     * @param string $domain
     * @param string $message
     * @param ?string $context Message context
     *
     * @return string Translated message or original message if no translation is found
     */
    public function translateInDomain(string $domain, string $message, ?string $context = null): string
    {
        return StaticTranslator::$instance->translateInDomain($domain, $message, $context);
    }

    /**
     * Translate a plural message
     *
     * The returned message is based on the given number to decide between the singular and plural forms.
     * That is also the case if no translation is found.
     *
     * @param string $singular Singular message
     * @param string $plural Plural message
     * @param ?int $number Number to decide between the returned singular and plural forms
     * @param ?string $context Message context
     *
     * @return string Translated message or original message if no translation is found
     */
    public function translatePlural(string $singular, string $plural, ?int $number, ?string $context = null): string
    {
        return $this->translationDomain === null
            ? StaticTranslator::$instance->translatePlural($singular, $plural, $number ?? 0, $context)
            : StaticTranslator::$instance->translatePluralInDomain(
                $this->translationDomain,
                $singular,
                $plural,
                $number ?? 0,
                $context
            );
    }

    /**
     * Translate a plural message in the given domain
     *
     * If no translation is found in the specified domain, the translation is also searched for in the default domain.
     *
     * The returned message is based on the given number to decide between the singular and plural forms.
     * That is also the case if no translation is found.
     *
     * @param string $domain
     * @param string $singular Singular message
     * @param string $plural Plural message
     * @param ?int $number Number to decide between the returned singular and plural forms
     * @param ?string $context Message context
     *
     * @return string Translated message or original message if no translation is found
     */
    public function translatePluralInDomain(
        string $domain,
        string $singular,
        string $plural,
        ?int $number,
        ?string $context = null
    ): string {
        return StaticTranslator::$instance->translatePluralInDomain(
            $domain,
            $singular,
            $plural,
            $number ?? 0,
            $context
        );
    }
}
