/*-
 *
 * Hedera Identify Snap
 *
 * Copyright (C) 2024 Hedera Hashgraph, LLC
 *
 * 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
 *
 *      http://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 { VerifiableCredential } from '@veramo/core';
import { normalizeCredential } from 'did-jwt-vc';
import cloneDeep from 'lodash.clonedeep';
import { CodecName, MULTICODECS } from '../constants';

export class Utils {
  public static timestampToString(
    data: string | number | Date | null | undefined,
  ): string {
    if (!data) {
      return '';
    }

    let timestamp: number;
    if (data instanceof Date) {
      timestamp = data.getTime() / 1000;
    } else if (typeof data === 'string' || typeof data === 'number') {
      timestamp = parseFloat(data.toString());
    } else {
      return '';
    }

    return new Date(timestamp * 1000).toUTCString();
  }

  /**
   * Adds the prefix to the EVM address.
   * @param address - EVM Account address.
   * @returns EVM address.
   */
  public static ensure0xPrefix(address: string): string {
    let result = address;
    if (!address.startsWith('0x')) {
      result = `0x${address}`;
    }
    return result.toLowerCase();
  }

  /**
   * Capitalizes the first letter of the given string.
   * @param string - The string to capitalize.
   * @returns The string with the first letter capitalized.
   */
  public static capitalizeFirstLetter(string: string): string {
    return string.charAt(0).toUpperCase() + string.slice(1);
  }

  /**
   * Prefix a buffer with a multicodec-packed.
   *
   * @param {CodecName} multicodec
   * @param {Uint8Array} data
   *
   * @returns {Uint8Array}
   */
  public static addMulticodecPrefix = (
    multicodec: CodecName,
    data: Uint8Array,
  ): Uint8Array => {
    let prefix;

    if (MULTICODECS[multicodec]) {
      prefix = Buffer.from(MULTICODECS[multicodec]);
    } else {
      throw new Error('multicodec not recognized');
    }

    return Buffer.concat([prefix, data], prefix.length + data.length);
  };

  /**
   * Function to decode JWT.
   *
   * @param jwt - JWT string.
   * @returns Verifiable Credential.
   */
  public static decodeJWT(jwt: string): VerifiableCredential {
    try {
      const normalizedVC = normalizeCredential(jwt);
      const vc = cloneDeep(normalizedVC);

      return vc;
    } catch (e) {
      throw new Error('Invalid JWT');
    }
  }
}