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

const genHeader = (size, buf, len) => {
    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`;
    data += `unsigned int index_html_size = ${size};\n`;
    return data;
};
let fileSize = 0;

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

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

task('default', series('inline', () => {
    return src('dist/inline.html')
        .pipe(through2.obj((file, enc, cb) => {
            fileSize = file.contents.length;
            return cb(null, file);
        }))
        .pipe(gzip())
        .pipe(through2.obj((file, enc, cb) => {
            const buf = file.contents;
            file.contents = Buffer.from(genHeader(fileSize, buf, buf.length));
            return cb(null, file);
        }))
        .pipe(rename("html.h"))
        .pipe(dest('../src/'));
}));