/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

package org.mozilla.focus.locale

import java.util.Locale

/**
 * This is a helper class to do typical locale switching operations without hitting StrictMode errors or adding
 * boilerplate to common activity subclasses.
 *
 * Inherit from `LocaleAwareFragmentActivity` or `LocaleAwareActivity`.
 */
object Locales {
    /**
     * Sometimes we want just the language for a locale, not the entire language tag. But Java's .getLanguage method is
     * wrong.
     *
     * This method is equivalent to the first part of [Locales.getLanguageTag].
     *
     * @return a language string, such as "he" for the Hebrew locales.
     */
    fun getLanguage(locale: Locale): String {
        // Modernize certain language codes.
        return when (val language = locale.language) {
            "iw" -> {
                "he"
            }

            "in" -> {
                "id"
            }

            "ji" -> {
                "yi"
            }

            else -> language
        }
    }

    /**
     * Gecko uses locale codes like "es-ES", whereas a Java [Locale] stringifies as "es_ES".
     *
     * This method approximates the Java 7 method `Locale#toLanguageTag()`.
     *
     * @return a locale string suitable for passing to Gecko.
     */
    @JvmStatic
    fun getLanguageTag(locale: Locale): String {
        val language = getLanguage(locale)
        val country = locale.country

        return if (country.isEmpty()) {
            language
        } else {
            "$language-$country"
        }
    }

    /** Parses a locale code [String] and returns the corresponding [Locale]. */
    fun parseLocaleCode(localeCode: String): Locale {
        var index: Int

        if (localeCode.indexOf('-').also { index = it } != -1 || localeCode.indexOf('_').also { index = it } != -1) {
            val langCode = localeCode.substring(0, index)
            val countryCode = localeCode.substring(index + 1)
            return Locale.Builder().setLanguage(langCode).setRegion(countryCode).build()
        }

        return Locale.forLanguageTag(localeCode)
    }
}