/*
 * The `chars`, `lookup`, and `decodeFromBase64` members of this file are
 * licensed under the following:
 *
 *     base64-arraybuffer
 *     https://github.com/niklasvh/base64-arraybuffer
 *
 *     Copyright (c) 2012 Niklas von Hertzen
 *     Licensed under the MIT license.
 *
 */
import { unzlibSync } from 'fflate';

const chars =
  'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';

// Use a lookup table to find the index.
const lookup = new Uint8Array(256);
for (let i = 0; i < chars.length; i++) {
  lookup[chars.charCodeAt(i)] = i;
}

export const decodeFromBase64 = (base64: string): Uint8Array => {
  let bufferLength = base64.length * 0.75;
  const len = base64.length;
  let i;
  let p = 0;
  let encoded1;
  let encoded2;
  let encoded3;
  let encoded4;

  if (base64[base64.length - 1] === '=') {
    bufferLength--;
    if (base64[base64.length - 2] === '=') {
      bufferLength--;
    }
  }

  const bytes = new Uint8Array(bufferLength);

  for (i = 0; i < len; i += 4) {
    encoded1 = lookup[base64.charCodeAt(i)];
    encoded2 = lookup[base64.charCodeAt(i + 1)];
    encoded3 = lookup[base64.charCodeAt(i + 2)];
    encoded4 = lookup[base64.charCodeAt(i + 3)];

    bytes[p++] = (encoded1 << 2) | (encoded2 >> 4);
    bytes[p++] = ((encoded2 & 15) << 4) | (encoded3 >> 2);
    bytes[p++] = ((encoded3 & 3) << 6) | (encoded4 & 63);
  }

  return bytes;
};

const arrayToString = (array: Uint8Array) => {
  let str = '';
  for (let i = 0; i < array.length; i++) {
    str += String.fromCharCode(array[i]);
  }
  return str;
};

export const decompressJson = (compressedJson: string): string =>
  arrayToString(unzlibSync(decodeFromBase64(compressedJson)));

export const padStart = (value: string, length: number, padChar: string) => {
  let padding = '';
  for (let idx = 0, len = length - value.length; idx < len; idx++) {
    padding += padChar;
  }
  return padding + value;
};