"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const BoxTypes = {
    ftyp: '66747970',
    ihdr: '69686472',
    jp2h: '6a703268',
    jp__: '6a502020',
    rreq: '72726571',
    xml_: '786d6c20'
};
const calculateRREQLength = (box) => {
    const unit = box.readUInt8(0);
    let offset = 1 + (2 * unit);
    const numStdFlags = box.readUInt16BE(offset);
    const flagsLength = numStdFlags * (2 + unit);
    offset = offset + 2 + flagsLength;
    const numVendorFeatures = box.readUInt16BE(offset);
    const featuresLength = numVendorFeatures * (16 + unit);
    return offset + 2 + featuresLength;
};
const parseIHDR = (box) => {
    return {
        height: box.readUInt32BE(4),
        width: box.readUInt32BE(8),
    };
};
exports.JP2 = {
    validate(buffer) {
        const signature = buffer.toString('hex', 4, 8);
        const signatureLength = buffer.readUInt32BE(0);
        if (signature !== BoxTypes.jp__ || signatureLength < 1) {
            return false;
        }
        const ftypeBoxStart = signatureLength + 4;
        const ftypBoxLength = buffer.readUInt32BE(signatureLength);
        const ftypBox = buffer.slice(ftypeBoxStart, ftypeBoxStart + ftypBoxLength);
        return ftypBox.toString('hex', 0, 4) === BoxTypes.ftyp;
    },
    calculate(buffer) {
        const signatureLength = buffer.readUInt32BE(0);
        const ftypBoxLength = buffer.readUInt16BE(signatureLength + 2);
        let offset = signatureLength + 4 + ftypBoxLength;
        const nextBoxType = buffer.toString('hex', offset, offset + 4);
        switch (nextBoxType) {
            case BoxTypes.rreq:
                // WHAT ARE THESE 4 BYTES?????
                const MAGIC = 4;
                offset = offset + 4 + MAGIC + calculateRREQLength(buffer.slice(offset + 4));
                return parseIHDR(buffer.slice(offset + 8, offset + 24));
            case BoxTypes.jp2h:
                return parseIHDR(buffer.slice(offset + 8, offset + 24));
            default:
                throw new TypeError('Unsupported header found: ' + buffer.toString('ascii', offset, offset + 4));
        }
    }
};
