sentencex 0.1.27

use std::collections::HashMap;
use std::sync::LazyLock;

pub const LANGUAGE_FALLBACKS: &[(&str, &[&str])] = &[
    ("aae", &["it"]),
    ("ab", &["ru"]),
    ("abs", &["id"]),
    ("ace", &["id"]),
    ("acm", &["ar"]),
    ("ady", &["ady-cyrl"]),
    ("aeb", &["aeb-arab"]),
    ("aeb-arab", &["ar"]),
    ("aln", &["sq"]),
    // Not so standard - als is supposed to be Tosk Albanian,
    // but in Wikipedia it's used for a Germanic language.
    // Use 'gsw' instead. See T25215
    ("als", &["gsw", "de"]),
    ("alt", &["ru"]),
    ("ami", &["zh-tw", "zh-hant", "zh", "zh-hans"]),
    ("an", &["es"]),
    ("anp", &["hi"]),
    ("apc", &["ar"]),
    ("arn", &["es"]),
    ("arq", &["ar"]),
    ("ary", &["ar"]),
    ("arz", &["ar"]),
    ("ast", &["es"]),
    ("atj", &["fr"]),
    ("av", &["ru"]),
    ("avk", &["fr", "es", "ru"]),
    ("awa", &["hi"]),
    ("ay", &["es"]),
    ("azb", &["fa"]),
    ("ba", &["ru"]),
    ("ban", &["id"]),
    ("ban-bali", &["ban"]),
    ("bar", &["de"]),
    // Deprecated: Use 'sgs' instead. See T27522
    ("bat-smg", &["sgs", "lt"]),
    ("bbc", &["bbc-latn"]),
    ("bbc-latn", &["id"]),
    ("bcc", &["fa"]),
    ("bci", &["fr"]),
    ("bdr", &["ms"]),
    ("be-tarask", &["be"]),
    // Deprecated: Use 'be-tarask' instead. See T11823
    ("be-x-old", &["be-tarask", "be"]),
    ("bew", &["id"]),
    ("bgn", &["fa"]),
    ("bh", &["bho"]),
    ("bjn", &["id"]),
    ("blk", &["my"]),
    ("bm", &["fr"]),
    ("bpy", &["bn"]),
    ("bqi", &["fa"]),
    ("btm", &["id"]),
    ("bug", &["id"]),
    ("bug-bugi", &["bug", "id"]),
    ("bxr", &["ru"]),
    ("ca", &["oc"]),
    ("cbk-zam", &["es"]),
    (
        "cdo",
        &[
            "cdo-latn", "cdo-hant", "nan-hant", "zh-hant", "zh", "zh-hans",
        ],
    ),
    (
        "cdo-hant",
        &["cdo", "cdo-latn", "nan-hant", "zh-hant", "zh", "zh-hans"],
    ),
    (
        "cdo-latn",
        &["cdo", "cdo-hant", "nan-hant", "zh-hant", "zh", "zh-hans"],
    ),
    ("ce", &["ru"]),
    ("co", &["it"]),
    (
        "cpx",
        &[
            "cpx-hant", "cpx-hans", "cpx-latn", "cdo", "zh-hant", "zh", "zh-hans",
        ],
    ),
    (
        "cpx-hans",
        &[
            "cpx", "cpx-hant", "cpx-latn", "cdo", "zh-hans", "zh", "zh-hant",
        ],
    ),
    (
        "cpx-hant",
        &[
            "cpx", "cpx-hans", "cpx-latn", "cdo", "zh-hant", "zh", "zh-hans",
        ],
    ),
    ("crh", &["crh-latn", "tr"]),
    ("crh-cyrl", &["tr"]),
    ("crh-latn", &["tr"]),
    ("cs", &["sk"]),
    ("csb", &["pl"]),
    ("cv", &["ru"]),
    ("de-at", &["de"]),
    ("de-ch", &["de"]),
    ("de-formal", &["de"]),
    ("dsb", &["hsb", "de"]),
    ("dtp", &["ms"]),
    ("dty", &["ne"]),
    ("dua", &["fr"]),
    ("egl", &["it"]),
    ("eml", &["it"]),
    ("es-formal", &["es"]),
    ("ext", &["es"]),
    ("fit", &["fi"]),
    // Deprecated: Use 'vro' instead. See T31186
    ("fiu-vro", &["vro", "et"]),
    ("fon", &["fr"]),
    ("frc", &["fr"]),
    ("frp", &["fr"]),
    ("frr", &["de"]),
    ("fur", &["it"]),
    ("gag", &["tr"]),
    ("gan", &["gan-hant", "gan-hans", "zh-hant", "zh", "zh-hans"]),
    ("gan-hans", &["gan", "gan-hant", "zh-hans", "zh", "zh-hant"]),
    ("gan-hant", &["gan", "gan-hans", "zh-hant", "zh", "zh-hans"]),
    ("gcf", &["fr"]),
    ("gcr", &["fr"]),
    ("gl", &["pt"]),
    ("gld", &["ru"]),
    ("glk", &["fa"]),
    ("gn", &["es"]),
    ("gom", &["gom-deva", "gom-latn"]),
    ("gom-deva", &["gom-latn"]),
    ("gor", &["id"]),
    ("gsw", &["de"]),
    ("guc", &["es"]),
    ("hak", &["zh-hant", "zh", "zh-hans"]),
    ("hif", &["hif-latn"]),
    ("hke", &["fr"]),
    ("hrx", &["de"]),
    ("hsb", &["dsb", "de"]),
    ("hsn", &["zh-hant", "zh", "zh-hans"]),
    ("ht", &["fr"]),
    ("hu-formal", &["hu"]),
    ("hyw", &["hy"]),
    ("iba", &["ms"]),
    ("ii", &["zh-cn", "zh-hans", "zh", "zh-hant"]),
    ("ike-cans", &["iu"]),
    ("ike-latn", &["iu"]),
    ("inh", &["ru"]),
    ("io", &["eo"]),
    ("iu", &["ike-cans"]),
    ("jut", &["da"]),
    ("jv", &["id"]),
    ("kaa", &["kk-latn", "kk-cyrl"]),
    ("kab", &["fr"]),
    ("kbd", &["kbd-cyrl"]),
    ("kbp", &["fr"]),
    ("kea", &["pt"]),
    ("kge", &["id"]),
    ("khw", &["ur"]),
    ("kiu", &["tr"]),
    ("kjh", &["ru"]),
    ("kjp", &["my"]),
    ("kk", &["kk-cyrl"]),
    ("kk-arab", &["kk", "kk-cyrl"]),
    ("kk-cn", &["kk-arab", "kk", "kk-cyrl"]),
    ("kk-cyrl", &["kk"]),
    ("kk-kz", &["kk-cyrl", "kk"]),
    ("kk-latn", &["kk", "kk-cyrl"]),
    ("kk-tr", &["kk-latn", "kk", "kk-cyrl"]),
    ("kl", &["da"]),
    ("ko-kp", &["ko"]),
    ("koi", &["ru"]),
    ("kr", &["knc"]),
    ("krc", &["ru"]),
    ("krl", &["fi"]),
    ("ks", &["ks-arab"]),
    ("ksh", &["de"]),
    ("ksw", &["my"]),
    ("ku", &["ku-latn"]),
    ("ku-arab", &["ku", "ckb"]),
    ("ku-latn", &["ku"]),
    ("kum", &["ru"]),
    ("kv", &["ru"]),
    ("lad", &["es"]),
    ("lb", &["de"]),
    ("lbe", &["ru"]),
    ("lez", &["ru", "az"]),
    ("li", &["nl"]),
    ("lij", &["it"]),
    ("liv", &["et"]),
    ("ljp", &["id"]),
    ("lki", &["fa"]),
    ("lld", &["it", "rm", "fur"]),
    ("lmo", &["pms", "eml", "lij", "vec", "it"]),
    ("ln", &["fr"]),
    ("lrc", &["fa"]),
    ("ltg", &["lv"]),
    ("lua", &["fr"]),
    ("luz", &["fa"]),
    ("lzh", &["zh-hant", "zh", "zh-hans"]),
    ("lzz", &["tr"]),
    ("mad", &["id"]),
    ("mag", &["hi"]),
    ("mai", &["hi"]),
    ("map-bms", &["jv", "id"]),
    ("mdf", &["myv", "ru"]),
    ("mg", &["fr"]),
    ("mhr", &["mrj", "ru"]),
    ("min", &["id"]),
    ("mnc-latn", &["mnc"]),
    ("mnc-mong", &["mnc"]),
    ("mnw", &["my"]),
    ("mo", &["ro"]),
    ("mrj", &["mhr", "ru"]),
    ("ms-arab", &["ms"]),
    ("mui", &["id"]),
    ("mwl", &["pt"]),
    ("myv", &["mdf", "ru"]),
    ("mzn", &["fa"]),
    ("nah", &["es"]),
    (
        "nan",
        &[
            "nan-latn-pehoeji",
            "nan-latn-tailo",
            "nan-hant",
            "cdo",
            "zh-hant",
            "zh",
            "zh-hans",
        ],
    ),
    (
        "nan-hant",
        &[
            "nan",
            "nan-latn-pehoeji",
            "nan-latn-tailo",
            "cdo",
            "zh-hant",
            "zh",
            "zh-hans",
        ],
    ),
    (
        "nan-latn-pehoeji",
        &[
            "nan-latn",
            "nan-latn-tailo",
            "nan",
            "nan-hant",
            "cdo",
            "zh-hant",
            "zh",
            "zh-hans",
        ],
    ),
    (
        "nan-latn-tailo",
        &[
            "nan-latn",
            "nan-latn-pehoeji",
            "nan",
            "nan-hant",
            "cdo",
            "zh-hant",
            "zh",
            "zh-hans",
        ],
    ),
    ("nap", &["it"]),
    ("nb", &["no", "nn"]),
    ("nds", &["de"]),
    ("nds-nl", &["nl"]),
    ("nia", &["id"]),
    ("nl-informal", &["nl"]),
    ("nn", &["no", "nb"]),
    // Deprecated: Use 'nb' or 'nn' instead.
    ("no", &["nb", "nn"]),
    ("nrm", &["nrf", "fr"]),
    ("nyo", &["ttj", "nyn", "lg", "sw"]),
    ("oc", &["ca", "fr"]),
    ("olo", &["fi"]),
    ("os", &["ru"]),
    ("pcd", &["fr"]),
    ("pdc", &["de"]),
    ("pdt", &["de"]),
    ("pfl", &["de"]),
    ("pms", &["it"]),
    ("pnt", &["el"]),
    ("pt", &["pt-br"]),
    ("pt-br", &["pt"]),
    ("pwn", &["zh-tw", "zh-hant", "zh", "zh-hans"]),
    ("qu", &["qug", "es"]),
    ("qug", &["qu", "es"]),
    ("rgn", &["it"]),
    ("rm", &["de"]),
    ("rmy", &["ro"]),
    // Deprecated: Use 'rup' instead. See T17988
    ("roa-rup", &["rup", "ro"]),
    ("roa-tara", &["it"]),
    ("rsk", &["sr-cyrl", "sr-ec"]),
    ("rue", &["uk", "ru"]),
    ("rup", &["ro"]),
    ("ruq", &["ruq-latn", "ro"]),
    ("ruq-cyrl", &["mk"]),
    ("ruq-latn", &["ro"]),
    ("rut", &["ru"]),
    ("sa", &["hi"]),
    ("sah", &["ru"]),
    ("scn", &["it"]),
    ("sdc", &["it"]),
    ("sdh", &["ckb", "fa"]),
    ("se", &["nb", "fi"]),
    ("se-fi", &["se", "fi", "sv"]),
    ("se-no", &["se", "nb", "nn"]),
    ("se-se", &["se", "sv"]),
    ("ses", &["fr"]),
    ("sg", &["fr"]),
    ("sgs", &["lt"]),
    (
        "sh",
        &["sh-latn", "sh-cyrl", "bs", "sr-latn", "sr-el", "hr"],
    ),
    ("sh-cyrl", &["sr-cyrl", "sr-ec", "sh", "sh-latn"]),
    (
        "sh-latn",
        &["sh", "sh-cyrl", "bs", "sr-latn", "sr-el", "hr"],
    ),
    ("shi", &["shi-latn", "fr"]),
    ("shy", &["shy-latn"]),
    ("shy-latn", &["fr"]),
    ("sjd", &["ru"]),
    ("sk", &["cs"]),
    ("skr", &["skr-arab"]),
    ("skr-arab", &["skr"]),
    ("sli", &["de"]),
    ("sma", &["sv", "nb"]),
    ("smn", &["fi"]),
    ("sr", &["sr-cyrl", "sr-ec", "sr-latn", "sr-el"]),
    ("sr-cyrl", &["sr-ec", "sr"]),
    ("sr-ec", &["sr-cyrl", "sr"]),
    ("sr-el", &["sr-latn", "sr"]),
    ("sr-latn", &["sr-el", "sr"]),
    ("srn", &["nl"]),
    ("sro", &["it"]),
    ("stq", &["de"]),
    ("sty", &["ru"]),
    ("su", &["id"]),
    ("szl", &["pl"]),
    ("szy", &["zh-tw", "zh-hant", "zh", "zh-hans"]),
    ("tay", &["zh-tw", "zh-hant", "zh", "zh-hans"]),
    ("tcy", &["kn"]),
    ("tet", &["pt"]),
    ("tg", &["tg-cyrl"]),
    ("tg-cyrl", &["tg"]),
    ("tg-latn", &["tg"]),
    ("trv", &["zh-tw", "zh-hant", "zh", "zh-hans"]),
    ("tt", &["tt-cyrl", "ru"]),
    ("ttj", &["nyo", "nyn", "lg", "sw"]),
    ("tt-cyrl", &["ru"]),
    ("ty", &["fr"]),
    ("tyv", &["ru"]),
    ("udm", &["ru"]),
    ("ug", &["ug-arab"]),
    ("vec", &["it"]),
    ("vep", &["et"]),
    ("vls", &["nl"]),
    ("vmf", &["de"]),
    ("vmw", &["pt"]),
    ("vot", &["fi"]),
    ("vro", &["et"]),
    ("wa", &["fr"]),
    ("wls", &["fr"]),
    ("wo", &["fr"]),
    ("wuu", &["wuu-hans", "wuu-hant", "zh-hans", "zh", "zh-hant"]),
    ("wuu-hans", &["wuu", "wuu-hant", "zh-hans", "zh", "zh-hant"]),
    ("wuu-hant", &["wuu", "wuu-hans", "zh-hant", "zh", "zh-hans"]),
    ("xal", &["ru"]),
    ("xmf", &["ka"]),
    ("yi", &["he"]),
    ("yue", &["yue-hant", "yue-hans"]),
    ("yue-hans", &["yue", "yue-hant"]),
    ("yue-hant", &["yue", "yue-hans"]),
    ("za", &["zh-hans", "zh", "zh-hant"]),
    // Deprecated: Use 'lzh' instead. See T30443
    ("zh-classical", &["lzh", "zh-hant", "zh", "zh-hans"]),
    ("zh-cn", &["zh-hans", "zh", "zh-hant"]),
    ("zh-hans", &["zh-cn", "zh", "zh-hant"]),
    ("zh-hant", &["zh-tw", "zh-hk", "zh", "zh-hans"]),
    ("zh-hk", &["zh-hant", "zh-tw", "zh", "zh-hans"]),
    // Deprecated: Use 'nan' instead. See T30442
    (
        "zh-min-nan",
        &[
            "nan",
            "nan-latn-pehoeji",
            "nan-latn-tailo",
            "nan-hant",
            "cdo",
            "zh-hant",
            "zh",
            "zh-hans",
        ],
    ),
    ("zh-mo", &["zh-hk", "zh-hant", "zh-tw", "zh", "zh-hans"]),
    ("zh-my", &["zh-sg", "zh-hans", "zh-cn", "zh", "zh-hant"]),
    ("zh-sg", &["zh-hans", "zh-cn", "zh", "zh-hant"]),
    ("zh-tw", &["zh-hant", "zh-hk", "zh", "zh-hans"]),
    // Deprecated: Use 'yue' instead. See T30441
    ("zh-yue", &["yue", "yue-hant", "yue-hans"]),
];

// Lazy-built lookup map to speed up queries and avoid linear scans
static FALLBACKS_MAP: LazyLock<HashMap<&'static str, &'static [&'static str]>> =
    LazyLock::new(|| {
        let mut map = HashMap::with_capacity(LANGUAGE_FALLBACKS.len());
        for (k, v) in LANGUAGE_FALLBACKS.iter() {
            map.insert(*k, *v);
        }
        map
    });

/// Get fallback languages for a given language code
pub fn get_fallbacks(lang: &str) -> Option<&'static [&'static str]> {
    FALLBACKS_MAP.get(lang).copied()
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_language_fallbacks() {
        assert_eq!(
            get_fallbacks("zh-cn"),
            Some(&["zh-hans", "zh", "zh-hant"][..])
        );
        assert_eq!(get_fallbacks("de-at"), Some(&["de"][..]));
        assert_eq!(get_fallbacks("en"), None);
    }

    #[test]
    fn test_direct_access() {
        // You can also iterate directly
        let count = LANGUAGE_FALLBACKS.len();
        assert!(count > 0);
    }

    #[test]
    fn test_hashmap_performance() {
        // Test that our LazyLock HashMap provides O(1) lookup
        let start = std::time::Instant::now();

        // Do multiple lookups to test performance
        for _ in 0..1000 {
            let _ = get_fallbacks("zh-cn");
            let _ = get_fallbacks("de-at");
            let _ = get_fallbacks("en");
            let _ = get_fallbacks("non-existent");
        }

        let duration = start.elapsed();

        // Should be very fast with HashMap (much faster than linear search)
        assert!(
            duration.as_millis() < 100,
            "HashMap lookups too slow: {:?}",
            duration
        );
    }
}