import { Transform } from "node:stream";
import File from "vinyl";
import tmp from "tmp";
import { execFile } from "node:child_process";
import { readFileSync, unlinkSync } from "node:fs";
import { src, dest } from "gulp";
import hashPaths from "../hash.js";

const FONT_PRESETS = {
    mono: { ranges: ["20-7F", "2205", "2E22-2E25", "2713", "2717"] },
    text: { ranges: ["20-7F", "A0-FF", "2000-206F", "20AC"] },
};

function compileFont() {
    return new Transform({
        objectMode: true,
        async transform(chunk: File, _, callback) {
            const [, variant, weight] = /([A-Z][a-z]+)-(\w+)\.ttf$/.exec(chunk.basename);
            const tmpOutput = tmp.fileSync({ discardDescriptor: true });
            const unicodes = FONT_PRESETS[variant.toLowerCase()].ranges;

            execFile("pyftsubset", [
                chunk.path,
                `--unicodes=${unicodes.join(",")}`,
                `--output-file=${tmpOutput.name}`,
                "--flavor=woff2",
            ]).once("exit", () => {
                chunk.path = `iosevka-adaedra-${variant.toLowerCase()}-${weight.toLowerCase()}.woff2`;
                chunk.contents = readFileSync(tmpOutput.name);
                chunk.base = null;

                unlinkSync(tmpOutput.name);
                callback(null, chunk);
            });
        },
    });
}

export const fonts = () =>
    src("vendor/*.ttf")
        .pipe(compileFont())
        .pipe(hashPaths("fonts.manifest"))
        .pipe(dest("dist/_assets"));