// loaders.gl
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors
import { compareArrayBuffers, concatenateArrayBuffers } from '@loaders.gl/loader-utils';
import { createZip64Info, setFieldToNumber } from "./zip64-info-generation.js";
// offsets accroding to https://en.wikipedia.org/wiki/ZIP_(file_format)
const COMPRESSION_METHOD_OFFSET = 8;
const COMPRESSED_SIZE_OFFSET = 18;
const UNCOMPRESSED_SIZE_OFFSET = 22;
const FILE_NAME_LENGTH_OFFSET = 26;
const EXTRA_FIELD_LENGTH_OFFSET = 28;
const FILE_NAME_OFFSET = 30n;
export const signature = new Uint8Array([0x50, 0x4b, 0x03, 0x04]);
/**
 * Parses local file header of zip file
 * @param headerOffset - offset in the archive where header starts
 * @param buffer - buffer containing whole array
 * @returns Info from the header
 */
export const parseZipLocalFileHeader = async (headerOffset, file) => {
    const mainHeader = new DataView(await file.slice(headerOffset, headerOffset + FILE_NAME_OFFSET));
    const magicBytes = mainHeader.buffer.slice(0, 4);
    if (!compareArrayBuffers(magicBytes, signature)) {
        return null;
    }
    const fileNameLength = mainHeader.getUint16(FILE_NAME_LENGTH_OFFSET, true);
    const extraFieldLength = mainHeader.getUint16(EXTRA_FIELD_LENGTH_OFFSET, true);
    const additionalHeader = await file.slice(headerOffset + FILE_NAME_OFFSET, headerOffset + FILE_NAME_OFFSET + BigInt(fileNameLength + extraFieldLength));
    const fileNameBuffer = additionalHeader.slice(0, fileNameLength);
    const extraDataBuffer = new DataView(additionalHeader.slice(fileNameLength, additionalHeader.byteLength));
    const fileName = new TextDecoder().decode(fileNameBuffer).split('\\').join('/');
    let fileDataOffset = headerOffset + FILE_NAME_OFFSET + BigInt(fileNameLength + extraFieldLength);
    const compressionMethod = mainHeader.getUint16(COMPRESSION_METHOD_OFFSET, true);
    let compressedSize = BigInt(mainHeader.getUint32(COMPRESSED_SIZE_OFFSET, true)); // add zip 64 logic
    let uncompressedSize = BigInt(mainHeader.getUint32(UNCOMPRESSED_SIZE_OFFSET, true)); // add zip 64 logic
    let offsetInZip64Data = 4;
    // looking for info that might be also be in zip64 extra field
    if (uncompressedSize === BigInt(0xffffffff)) {
        uncompressedSize = extraDataBuffer.getBigUint64(offsetInZip64Data, true);
        offsetInZip64Data += 8;
    }
    if (compressedSize === BigInt(0xffffffff)) {
        compressedSize = extraDataBuffer.getBigUint64(offsetInZip64Data, true);
        offsetInZip64Data += 8;
    }
    if (fileDataOffset === BigInt(0xffffffff)) {
        fileDataOffset = extraDataBuffer.getBigUint64(offsetInZip64Data, true); // setting it to the one from zip64
    }
    return {
        fileNameLength,
        fileName,
        extraFieldLength,
        fileDataOffset,
        compressedSize,
        compressionMethod
    };
};
/**
 * generates local header for the file
 * @param options info that can be placed into local header
 * @returns buffer with header
 */
export function generateLocalHeader(options) {
    const optionsToUse = {
        ...options,
        extraLength: 0,
        fnlength: options.fileName.length
    };
    let zip64header = new ArrayBuffer(0);
    const optionsToZip64 = {};
    if (optionsToUse.length >= 0xffffffff) {
        optionsToZip64.size = optionsToUse.length;
        optionsToUse.length = 0xffffffff;
    }
    if (Object.keys(optionsToZip64).length) {
        zip64header = createZip64Info(optionsToZip64);
        optionsToUse.extraLength = zip64header.byteLength;
    }
    // base length without file name and extra info is static
    const header = new DataView(new ArrayBuffer(Number(FILE_NAME_OFFSET)));
    for (const field of ZIP_HEADER_FIELDS) {
        setFieldToNumber(header, field.size, field.offset, optionsToUse[field.name ?? ''] ?? field.default ?? 0);
    }
    const encodedName = new TextEncoder().encode(optionsToUse.fileName);
    const resHeader = concatenateArrayBuffers(header.buffer, encodedName, zip64header);
    return resHeader;
}
const ZIP_HEADER_FIELDS = [
    // Local file header signature = 0x04034b50
    {
        offset: 0,
        size: 4,
        default: new DataView(signature.buffer).getUint32(0, true)
    },
    // Version needed to extract (minimum)
    {
        offset: 4,
        size: 2,
        default: 45
    },
    // General purpose bit flag
    {
        offset: 6,
        size: 2,
        default: 0
    },
    // Compression method
    {
        offset: 8,
        size: 2,
        default: 0
    },
    // File last modification time
    {
        offset: 10,
        size: 2,
        default: 0
    },
    // File last modification date
    {
        offset: 12,
        size: 2,
        default: 0
    },
    // CRC-32 of uncompressed data
    {
        offset: 14,
        size: 4,
        name: 'crc32'
    },
    // Compressed size (or 0xffffffff for ZIP64)
    {
        offset: 18,
        size: 4,
        name: 'length'
    },
    // Uncompressed size (or 0xffffffff for ZIP64)
    {
        offset: 22,
        size: 4,
        name: 'length'
    },
    // File name length (n)
    {
        offset: 26,
        size: 2,
        name: 'fnlength'
    },
    // Extra field length (m)
    {
        offset: 28,
        size: 2,
        default: 0,
        name: 'extraLength'
    }
];