use std::{fs::File, io, path::Path};

use icu_locid::LanguageIdentifier;
use xml::{writer::XmlEvent, EmitterConfig, EventWriter};

use crate::{Bundle, Message, WriteError};

pub fn export_file(
    bundle: &Bundle,
    locale: LanguageIdentifier,
    path: &Path,
) -> Result<(), WriteError> {
    let mut file = File::create(path).unwrap();
    export_fh(bundle, locale, &mut file)
}

pub fn export_fh(
    bundle: &Bundle,
    locale: LanguageIdentifier,
    fh: &mut File,
) -> Result<(), WriteError> {
    let mut writer = EmitterConfig::new()
        .perform_indent(true)
        .create_writer(fh);

    writer
        .write(
            XmlEvent::start_element("xliff")
                .attr("xmlns", "urn:oasis:names:tc:xliff:document:2.0")
                .attr("version", "2.0")
                .attr("srcLang", &format!("{}", locale)),
        )
        .unwrap();
    writer
        .write(XmlEvent::start_element("file").attr("id", "main"))
        .unwrap();

    for (key, message) in bundle.message_iter() {
        write_message(&mut writer, key, message, &locale);
    }

    writer.write(XmlEvent::end_element()).unwrap();
    writer.write(XmlEvent::end_element()).unwrap();
    Ok(())
}

fn write_message<T>(
    writer: &mut EventWriter<T>,
    key: &str,
    message: &Message,
    locale: &LanguageIdentifier,
) where
    T: std::io::Write,
{
    [
        XmlEvent::start_element("unit").attr("id", key).into(),
        XmlEvent::start_element("notes").into(),
        XmlEvent::start_element("note").into(),
        XmlEvent::characters(message.description()).into(),
        XmlEvent::end_element().into(),
        XmlEvent::end_element().into(),
        XmlEvent::start_element("segment").into(),
        XmlEvent::start_element("source").into(),
        XmlEvent::characters(message.variant(locale).unwrap().content()).into(),
        XmlEvent::end_element().into(),
        XmlEvent::end_element().into(),
        XmlEvent::end_element().into(),
    ]
    .into_iter()
    .for_each(|elem: XmlEvent| writer.write(elem).unwrap());
}