// ============================================================================

// Base64 / Binary Encoding Utilities

// ============================================================================

export function concatBuffers(chunks: Uint8Array[]): Uint8Array {

if (chunks.length === 0) return new Uint8Array(0);

if (chunks.length === 1) return chunks[0];

const total = chunks.reduce((n, c) => n + c.length, 0);

const out = new Uint8Array(total);

let offset = 0;

for (const chunk of chunks) {

out.set(chunk, offset);

offset += chunk.length;

}

return out;

}

/** Convert a Uint8Array to an ArrayBuffer suitable for SQL BLOB binding. */

export function toBuffer(bytes: Uint8Array): ArrayBuffer {

if (bytes.byteOffset === 0 && bytes.byteLength === bytes.buffer.byteLength) {

return bytes.buffer as ArrayBuffer;

}

return bytes.buffer.slice(bytes.byteOffset, bytes.byteOffset + bytes.byteLength) as ArrayBuffer;

}

/** Decode a row's data column into a Uint8Array, handling both BLOB and legacy base64. */

export function rowDataToBytes(data: ArrayBuffer | string | null): Uint8Array {

if (data instanceof ArrayBuffer) return new Uint8Array(data);

if (typeof data === 'string' && data.length > 0) return base64ToUint8Array(data);

return new Uint8Array(0);

}

/** Decode a base64 string into a Uint8Array. */

export function base64ToUint8Array(base64: string): Uint8Array {

const binary = atob(base64);

const bytes = new Uint8Array(binary.length);

for (let i = 0; i < binary.length; i++) {

bytes[i] = binary.charCodeAt(i);

}

return bytes;

}