use allsorts::{
    binary::read::ReadScope,
    font::{Font, MatchingPresentation},
    font_data::FontData as AllsortsFontData,
    subset::subset,
    tag,
};
use epaint::{
    text::{FontData, FontDefinitions, FontTweak},
    FontFamily,
};
use std::{
    collections::BTreeMap,
    env,
    fs::File,
    io::{BufWriter, Write},
    path::Path,
    sync::Arc,
};

include!(concat!(
    env!("CARGO_MANIFEST_DIR"),
    "/src/unicode_helper.rs"
));

fn font_stripper(from: &str, out: &str, unicodes: Vec<char>) -> Result<Vec<u8>, String> {
    let font_path = format!("{}/assets/{}", env!("CARGO_MANIFEST_DIR"), from);
    let font_data = std::fs::read(&font_path).map_err(|e| e.to_string())?;
    let scope = ReadScope::new(&font_data);
    let font_file = scope
        .read::<AllsortsFontData>()
        .map_err(|e| format!("Failed to read font data: {}", e))?;
    let provider = font_file
        .table_provider(0)
        .map_err(|e| format!("Failed to get table provider: {}", e))?;
    let mut font = Font::new(provider).map_err(|e| format!("Failed to create font: {:?}", e))?;

    let mut glyph_ids = Vec::new();
    for &ch in &unicodes {
        let mut glyph_ids_curr = font
            .map_glyphs(
                &ch.to_string(),
                tag::LATN,
                MatchingPresentation::NotRequired,
            )
            .into_iter()
            .map(|glyph| glyph.glyph_index)
            .collect();

        glyph_ids.append(&mut glyph_ids_curr);
    }
    // Include .notdef glyph
    glyph_ids.push(0);
    glyph_ids.sort();
    glyph_ids.dedup();

    let subset_data = subset(&font.font_table_provider, &glyph_ids)
        .map_err(|e| format!("Failed to subset font: {}", e))?;

    let new_path = [&env::var("OUT_DIR").unwrap(), out].concat();
    std::fs::write(&new_path, &subset_data)
        .map_err(|e| format!("Failed to write subset font: {}", e))?;

    Ok(subset_data)
}

fn main() {
    // rebuild if contents of `assets` folder changed
    println!("cargo:rerun-if-changed=assets/*");

    let mut main_chars: Vec<char> =
		b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyzsu0123456789?.,!(){}[]-_=+-/<>'\\ :^*`@#$%&|~;"
			.iter()
			.map(|c| *c as char)
			.collect();

    main_chars.append(&mut vec!['π', '"']);

    {
        let filtered_chars: Vec<char> = main_chars
            .iter()
            .filter(|c| !c.is_alphanumeric())
            .cloned()
            .collect();

        let chars_array = format!(
            "const VALID_EXTRA_CHARS: [char; {}] = {};",
            filtered_chars.len(),
            to_chars_array(filtered_chars),
        );
        let path = Path::new(&env::var("OUT_DIR").unwrap()).join("valid_chars.rs");
        let mut file = BufWriter::new(File::create(path).expect("Could not save compressed_data"));

        write!(&mut file, "{}", chars_array).expect("unable to write chars_array");
    }

    let fonts = FontDefinitions {
        font_data: BTreeMap::from([
            (
                "Ubuntu-Light".to_owned(),
                Arc::new(FontData::from_owned(
                    font_stripper(
                        "Ubuntu-Light.ttf",
                        "ubuntu-light.ttf",
                        [main_chars, vec!['∫']].concat(),
                    )
                    .unwrap(),
                )),
            ),
            (
                "NotoEmoji-Regular".to_owned(),
                Arc::new(FontData::from_owned(
                    font_stripper(
                        "NotoEmoji-Regular.ttf",
                        "noto-emoji.ttf",
                        vec!['🌞', '🌙', '✖'],
                    )
                    .unwrap(),
                )),
            ),
            (
                "emoji-icon-font".to_owned(),
                Arc::new(
                    FontData::from_owned(
                        font_stripper("emoji-icon-font.ttf", "emoji-icon.ttf", vec!['⚙']).unwrap(),
                    )
                    .tweak(FontTweak {
                        scale: 0.8,
                        y_offset_factor: 0.07,
                        y_offset: -0.0333,
                    }),
                ),
            ),
        ]),
        families: BTreeMap::from([
            (
                FontFamily::Monospace,
                vec![
                    "Ubuntu-Light".to_owned(),
                    "NotoEmoji-Regular".to_owned(),
                    "emoji-icon-font".to_owned(),
                ],
            ),
            (
                FontFamily::Proportional,
                vec![
                    "Ubuntu-Light".to_owned(),
                    "NotoEmoji-Regular".to_owned(),
                    "emoji-icon-font".to_owned(),
                ],
            ),
        ]),
    };

    let data = bincode::serialize(&fonts).unwrap();

    let zstd_levels = zstd::compression_level_range();
    let data_compressed =
        zstd::encode_all(data.as_slice(), *zstd_levels.end()).expect("Could not compress data");

    let path = Path::new(&env::var("OUT_DIR").unwrap()).join("compressed_data");
    let mut file = BufWriter::new(File::create(path).expect("Could not save compressed_data"));

    file.write_all(data_compressed.as_slice())
        .expect("Failed to save compressed data");
}