// SPDX-License-Identifier: GPL-3.0-only

use i18n_embed::{
    DefaultLocalizer, LanguageLoader, Localizer,
    fluent::{FluentLanguageLoader, fluent_language_loader},
};
use icu::collator::{
    Collator, CollatorBorrowed, CollatorPreferences, options::CollatorOptions,
    preferences::CollationNumericOrdering,
};
use icu::locale::Locale;
use rust_embed::RustEmbed;
use std::sync::LazyLock;

#[derive(RustEmbed)]
#[folder = "i18n/"]
struct Localizations;

pub static LANGUAGE_LOADER: LazyLock<FluentLanguageLoader> = LazyLock::new(|| {
    let loader: FluentLanguageLoader = fluent_language_loader!();

    loader
        .load_fallback_language(&Localizations)
        .expect("Error while loading fallback language");

    loader
});

pub static LANGUAGE_SORTER: LazyLock<CollatorBorrowed> = LazyLock::new(|| {
    let create_collator = |locale: Locale| {
        let mut prefs = CollatorPreferences::from(locale);
        prefs.numeric_ordering = Some(CollationNumericOrdering::True);
        Collator::try_new(prefs, CollatorOptions::default()).ok()
    };

    Locale::try_from_str(&LANGUAGE_LOADER.current_language().to_string())
            .ok()
            .and_then(create_collator)
            .or_else(|| {
                Locale::try_from_str(&LANGUAGE_LOADER.fallback_language().to_string())
                    .ok()
                    .and_then(create_collator)
            })
            .unwrap_or_else(|| {
                let locale = Locale::try_from_str("en-US").expect("en-US is a valid BCP-47 tag");
                create_collator(locale)
                    .expect("Creating a collator from the system's current language, the fallback language, or American English should succeed")
            })
});

#[macro_export]
macro_rules! fl {
    ($message_id:literal) => {{
        i18n_embed_fl::fl!($crate::localize::LANGUAGE_LOADER, $message_id)
    }};

    ($message_id:literal, $($args:expr),*) => {{
        i18n_embed_fl::fl!($crate::localize::LANGUAGE_LOADER, $message_id, $($args), *)
    }};
}

// Get the `Localizer` to be used for localizing this library.
pub fn localizer() -> Box<dyn Localizer> {
    Box::from(DefaultLocalizer::new(&*LANGUAGE_LOADER, &Localizations))
}

pub fn localize() {
    let localizer = localizer();
    let requested_languages = i18n_embed::DesktopLanguageRequester::requested_languages();

    if let Err(error) = localizer.select(&requested_languages) {
        eprintln!(
            "Error while loading language for COSMIC Text Editor {}",
            error
        );
    }
}