const { src, dest, task } = require("gulp");
const clean = require('gulp-clean');
const inlineSource = require('gulp-inline-source');
const rename = require("gulp-rename");
const through = require('through2');

const toCHeader = () => {
    return through.obj((file, enc, cb) => {
        const buf = file.contents;
        const len = buf.length;
        let idx = 0;
        let data = "unsigned char index_html[] = {\n  ";

        for (const value of buf) {
            idx++;

            let current = value < 0 ? value + 256 : value;

            data += "0x";
            data += (current >>> 4).toString(16);
            data += (current & 0xF).toString(16);

            if (idx === len) {
                data += "\n";
            } else {
                data += idx % 12 === 0 ? ",\n  " : ", ";
            }
        }

        data += "};\n";
        data += `unsigned int index_html_len = ${len};\n`;
        file.contents = Buffer.from(data);

        return cb(null, file);
    });
};

task('clean', () => {
    return src('dist', {read: false, allowEmpty: true})
        .pipe(clean());
});

task('default', () => {
    return src('dist/index.html')
        .pipe(inlineSource())
        .pipe(toCHeader())
        .pipe(rename("html.h"))
        .pipe(dest('../src/'));
});