/**
 * Strip EXIF and other metadata from images without external dependencies
 * Handles JPEG and PNG formats
 */
/**
 * Remove EXIF data from JPEG images
 * Finds the EXIF marker (0xFFE1) and removes everything up to the actual image data
 */
function stripJpegExif(buffer) {
    // JPEG starts with FFD8
    if (buffer[0] !== 0xff || buffer[1] !== 0xd8) {
        return buffer;
    }
    let pos = 2;
    while (pos < buffer.length) {
        // Find marker (0xFF)
        if (buffer[pos] !== 0xff) {
            pos++;
            continue;
        }
        const marker = buffer[pos + 1];
        pos += 2;
        // If we hit image data (0xDA = SOS - Start of Scan), keep everything from here
        if (marker === 0xda) {
            return Buffer.concat([Buffer.from([0xff, 0xd8]), buffer.slice(pos - 2)]);
        }
        // EXIF marker is 0xE1 (APP1)
        if (marker === 0xe1) {
            // Read length of this segment (big-endian)
            const length = buffer.readUInt16BE(pos);
            // Skip this segment entirely
            pos += length;
        }
        else if (
        // Skip other markers but keep them
        marker === 0xd0 ||
            marker === 0xd1 ||
            marker === 0xd2 ||
            marker === 0xd3 ||
            marker === 0xd4 ||
            marker === 0xd5 ||
            marker === 0xd6 ||
            marker === 0xd7 ||
            marker === 0xd8 ||
            marker === 0xd9 ||
            marker === 0x00 ||
            marker === 0x01) {
            // RSTm and padding, no length to skip
        }
        else if (marker !== 0xff) {
            // Other markers have length fields
            const length = buffer.readUInt16BE(pos);
            pos += length;
        }
    }
    return buffer;
}
/**
 * Remove metadata chunks from PNG images
 * PNG format stores metadata in various chunks - we keep only essential ones
 */
function stripPngExif(buffer) {
    // PNG signature
    const pngSignature = Buffer.from([0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a]);
    // Check if it's a valid PNG
    if (!buffer.slice(0, 8).equals(pngSignature)) {
        return buffer;
    }
    const chunks = [pngSignature];
    let pos = 8;
    // Chunks we want to keep (critical for image rendering)
    const keepChunks = new Set(['IHDR', 'PLTE', 'IDAT', 'IEND', 'gAMA', 'cHRM']);
    while (pos < buffer.length) {
        if (pos + 8 > buffer.length)
            break;
        // Read chunk length (4 bytes, big-endian)
        const length = buffer.readUInt32BE(pos);
        // Read chunk type (4 bytes)
        const chunkType = buffer.slice(pos + 4, pos + 8).toString('ascii');
        // Calculate total chunk size (length + type + CRC)
        const totalChunkSize = 4 + 4 + length + 4;
        if (pos + totalChunkSize > buffer.length)
            break;
        // Keep critical chunks and discard metadata
        if (keepChunks.has(chunkType)) {
            chunks.push(buffer.slice(pos, pos + totalChunkSize));
        }
        pos += totalChunkSize;
    }
    return Buffer.concat(chunks);
}
/**
 * Remove EXIF and metadata from image buffer based on file extension
 * Supports: JPEG, JPG, PNG
 *
 * @param buffer Image file buffer
 * @param filename Original filename (used to determine format)
 * @returns Buffer with EXIF/metadata stripped
 */
export function stripImageExif(buffer, filename) {
    const ext = filename.toLowerCase().split('.').pop() || '';
    if (ext === 'jpg' || ext === 'jpeg') {
        return stripJpegExif(buffer);
    }
    if (ext === 'png') {
        return stripPngExif(buffer);
    }
    // For other formats, return as-is
    // (WebP, GIF, etc. would require more complex handling)
    return buffer;
}
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