/**
 *  Copyright 2026 Angus.Fenying <fenying@litert.org>
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *    https://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

import * as eL from './Errors.js';

/**
 * Transform a binary UUID (16-byte buffer) into its standard string
 * representation.
 *
 * > Not for Snowflake (series) IDs, which are not UUID family and have different formats.
 *
 * @param buffer A 16-byte buffer representing the binary form of a UUID.
 * @returns A string representation of the UUID.
 *
 * @throws {E_INVALID_UUID} If the input buffer is not 16 bytes long.
 */
export function uuidToString(buffer: Buffer): string {

    if (buffer.length !== 16) {

        throw new eL.E_INVALID_UUID();
    }

    const hex = buffer.toString('hex');

    return `${
        hex.slice(0, 8)
    }-${
        hex.slice(8, 12)
    }-${
        hex.slice(12, 16)
    }-${
        hex.slice(16, 20)
    }-${
        hex.slice(20, 32)
    }`;
}

/**
 * Transform a UUID string into its binary form (16-byte buffer).
 *
 * > Not for Snowflake (series) IDs, which are not UUID family and have different formats.
 *
 * @param uuid A string representation of a UUID.
 * @returns A 16-byte buffer representing the binary form of the UUID.
 *
 * @throws {E_INVALID_UUID} If the input string is not a valid UUID format.
 */
export function uuidToBuffer(uuid: string): Buffer {

    if (uuid.length !== 36) {

        throw new eL.E_INVALID_UUID();
    }

    const hex = uuid.replace(/-/g, '');

    const buf = Buffer.from(hex, 'hex');

    if (buf.length !== 16) {

        throw new eL.E_INVALID_UUID();
    }

    return buf;
}