/*
 * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
 *
 * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
 */

include!(concat!(env!("OUT_DIR"), "/locales.rs"));

const TRADITIONAL_CHINESE: [&str; 4] = ["hant", "tw", "hk", "mo"];

pub fn locale_or_default(name: &str) -> &'static Locale {
    if let Some(locale) = locale(name) {
        return locale;
    }

    let mut subtags = name.split(['_', '-']);
    let language = subtags.next().unwrap_or(name);

    if language.eq_ignore_ascii_case("zh")
        && subtags.any(|subtag| {
            TRADITIONAL_CHINESE
                .iter()
                .any(|variant| subtag.eq_ignore_ascii_case(variant))
        })
    {
        return &ZH_TW_LOCALES;
    }

    locale_by_language(language).unwrap_or(&EN_US_LOCALES)
}

#[cfg(test)]
mod tests {
    use super::{ALL_LOCALES, locale, locale_or_default};

    const LOCALES: [&str; 37] = [
        "en-US", "es-ES", "fr-FR", "de-DE", "it-IT", "pt-PT", "pt-BR", "nl-NL", "da-DK", "ca-ES",
        "el-GR", "sv-SE", "pl-PL", "ru-RU", "uk-UA", "bg-BG", "cs-CZ", "sk-SK", "sl-SI", "hr-HR",
        "lt-LT", "hu-HU", "ro-RO", "fi-FI", "nb-NO", "tr-TR", "zh-CN", "zh-TW", "ja-JP", "ko-KR",
        "th-TH", "vi-VN", "id-ID", "hi-IN", "ar-SA", "he-IL", "fa-IR",
    ];

    #[test]
    fn locales_are_named_after_themselves() {
        for lang in LOCALES {
            assert_eq!(locale(lang).expect("locale must exist").name, lang);
        }
        assert_eq!(ALL_LOCALES.len(), LOCALES.len());
    }

    #[test]
    fn bare_and_hyphenated_language_tags_resolve() {
        for (input, expected) in [
            ("es-ES", "es-ES"),
            ("es", "es-ES"),
            ("es-MX", "es-ES"),
            ("pt-BR", "pt-BR"),
            ("pt-PT", "pt-PT"),
            ("pt", "pt-BR"),
            ("zh-Hans", "zh-CN"),
            ("zh-Hant", "zh-TW"),
            ("zh-HK", "zh-TW"),
            ("zh-Hant-HK", "zh-TW"),
            ("zh", "zh-CN"),
            ("zz", "en-US"),
            ("", "en-US"),
            // BCP 47 tags are case-insensitive
            ("ES", "es-ES"),
            ("es-es", "es-ES"),
            ("PT-br", "pt-BR"),
            ("EL-GR", "el-GR"),
            ("ZH-HANT", "zh-TW"),
        ] {
            assert_eq!(
                locale_or_default(input).name,
                expected,
                "failed for {input}"
            );
        }
    }

    #[test]
    fn right_to_left_locales_are_flagged() {
        for lang in ["ar-SA", "he-IL", "fa-IR"] {
            assert_eq!(
                locale_or_default(lang).direction,
                "rtl",
                "failed for {lang}"
            );
        }
        for lang in ["en-US", "de-DE", "ja-JP", "ru-RU"] {
            assert_eq!(
                locale_or_default(lang).direction,
                "ltr",
                "failed for {lang}"
            );
        }
    }
}