// Package boot animation as a zip with STORE (no compression) method
// Android bootanimation.zip MUST use store method, not deflate

const fs = require('fs');
const path = require('path');

const baseDir = 'C:\\Users\\PCOEM\\AeThexOS\\bootanimation';
const outFile = 'C:\\Users\\PCOEM\\AeThexOS\\bootanimation.zip';

// Collect all files to include
const files = [];

// desc.txt
files.push({ name: 'desc.txt', path: path.join(baseDir, 'desc.txt') });

// part0 PNGs
const part0 = fs.readdirSync(path.join(baseDir, 'part0')).sort();
for (const f of part0) {
    files.push({ name: 'part0/' + f, path: path.join(baseDir, 'part0', f) });
}

// part1 PNGs
const part1 = fs.readdirSync(path.join(baseDir, 'part1')).sort();
for (const f of part1) {
    files.push({ name: 'part1/' + f, path: path.join(baseDir, 'part1', f) });
}

// Build ZIP manually with STORE method (no compression)
const entries = [];
let offset = 0;

for (const file of files) {
    const data = fs.readFileSync(file.path);
    const nameBytes = Buffer.from(file.name, 'utf8');

    // Local file header (30 bytes + name length)
    const localHeader = Buffer.alloc(30 + nameBytes.length);
    localHeader.writeUInt32LE(0x04034b50, 0);   // Local file header signature
    localHeader.writeUInt16LE(10, 4);            // Version needed (1.0)
    localHeader.writeUInt16LE(0, 6);             // General purpose bit flag
    localHeader.writeUInt16LE(0, 8);             // Compression method: STORE
    localHeader.writeUInt16LE(0, 10);            // Last mod time
    localHeader.writeUInt16LE(0, 12);            // Last mod date

    // CRC-32
    const crc = crc32(data);
    localHeader.writeUInt32LE(crc, 14);
    localHeader.writeUInt32LE(data.length, 18);  // Compressed size
    localHeader.writeUInt32LE(data.length, 22);  // Uncompressed size
    localHeader.writeUInt16LE(nameBytes.length, 26); // File name length
    localHeader.writeUInt16LE(0, 28);            // Extra field length
    nameBytes.copy(localHeader, 30);

    entries.push({
        localHeaderOffset: offset,
        nameBytes,
        data,
        crc
    });

    offset += localHeader.length + data.length;
}

// Build the full ZIP
const centralDirStart = offset;
const centralHeaders = [];

for (const entry of entries) {
    const ch = Buffer.alloc(46 + entry.nameBytes.length);
    ch.writeUInt32LE(0x02014b50, 0);     // Central directory header signature
    ch.writeUInt16LE(10, 4);             // Version made by
    ch.writeUInt16LE(10, 6);             // Version needed
    ch.writeUInt16LE(0, 8);              // Flags
    ch.writeUInt16LE(0, 10);             // Compression: STORE
    ch.writeUInt16LE(0, 12);             // Time
    ch.writeUInt16LE(0, 14);             // Date
    ch.writeUInt32LE(entry.crc, 16);     // CRC
    ch.writeUInt32LE(entry.data.length, 20);  // Compressed size
    ch.writeUInt32LE(entry.data.length, 24);  // Uncompressed size
    ch.writeUInt16LE(entry.nameBytes.length, 28); // Name length
    ch.writeUInt16LE(0, 30);             // Extra length
    ch.writeUInt16LE(0, 32);             // Comment length
    ch.writeUInt16LE(0, 34);             // Disk number start
    ch.writeUInt16LE(0, 36);             // Internal file attributes
    ch.writeUInt32LE(0, 38);             // External file attributes
    ch.writeUInt32LE(entry.localHeaderOffset, 42); // Relative offset of local header
    entry.nameBytes.copy(ch, 46);
    centralHeaders.push(ch);
    offset += ch.length;
}

// End of central directory
const eocd = Buffer.alloc(22);
eocd.writeUInt32LE(0x06054b50, 0);           // EOCD signature
eocd.writeUInt16LE(0, 4);                    // Disk number
eocd.writeUInt16LE(0, 6);                    // Disk with central dir
eocd.writeUInt16LE(entries.length, 8);       // Entries on this disk
eocd.writeUInt16LE(entries.length, 10);      // Total entries
const centralDirSize = offset - centralDirStart;
eocd.writeUInt32LE(centralDirSize, 12);      // Central dir size
eocd.writeUInt32LE(centralDirStart, 16);     // Central dir offset
eocd.writeUInt16LE(0, 20);                   // Comment length

// Write everything
const fd = fs.openSync(outFile, 'w');
for (let i = 0; i < entries.length; i++) {
    const e = entries[i];
    const localHeader = Buffer.alloc(30 + e.nameBytes.length);
    localHeader.writeUInt32LE(0x04034b50, 0);
    localHeader.writeUInt16LE(10, 4);
    localHeader.writeUInt16LE(0, 6);
    localHeader.writeUInt16LE(0, 8);
    localHeader.writeUInt16LE(0, 10);
    localHeader.writeUInt16LE(0, 12);
    localHeader.writeUInt32LE(e.crc, 14);
    localHeader.writeUInt32LE(e.data.length, 18);
    localHeader.writeUInt32LE(e.data.length, 22);
    localHeader.writeUInt16LE(e.nameBytes.length, 26);
    localHeader.writeUInt16LE(0, 28);
    e.nameBytes.copy(localHeader, 30);
    fs.writeSync(fd, localHeader);
    fs.writeSync(fd, e.data);
}
for (const ch of centralHeaders) {
    fs.writeSync(fd, ch);
}
fs.writeSync(fd, eocd);
fs.closeSync(fd);

const stat = fs.statSync(outFile);
console.log(`bootanimation.zip created: ${stat.size} bytes (${files.length} files)`);

// CRC-32 implementation
function crc32(buf) {
    let crc = 0xFFFFFFFF;
    for (let i = 0; i < buf.length; i++) {
        crc ^= buf[i];
        for (let j = 0; j < 8; j++) {
            crc = (crc >>> 1) ^ (crc & 1 ? 0xEDB88320 : 0);
        }
    }
    return (crc ^ 0xFFFFFFFF) >>> 0;
}