// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.

// TODO(petamoriken): enable prefer-primordials for node polyfills
// deno-lint-ignore-file prefer-primordials

import { ERR_INVALID_URI } from "ext:deno_node/internal/errors.ts";

export const hexTable = new Array(256);
for (let i = 0; i < 256; ++i) {
  hexTable[i] = "%" + ((i < 16 ? "0" : "") + i.toString(16)).toUpperCase();
}

// deno-fmt-ignore
export const isHexTable = new Int8Array([
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0 - 15
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 16 - 31
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 32 - 47
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, // 48 - 63
  0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 64 - 79
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 80 - 95
  0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 96 - 111
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 112 - 127
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 128 ...
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  // ... 256
]);

export function encodeStr(
  str: string,
  noEscapeTable: Int8Array,
  hexTable: string[],
): string {
  const len = str.length;
  if (len === 0) return "";

  let out = "";
  let lastPos = 0;

  for (let i = 0; i < len; i++) {
    let c = str.charCodeAt(i);
    // ASCII
    if (c < 0x80) {
      if (noEscapeTable[c] === 1) continue;
      if (lastPos < i) out += str.slice(lastPos, i);
      lastPos = i + 1;
      out += hexTable[c];
      continue;
    }

    if (lastPos < i) out += str.slice(lastPos, i);

    // Multi-byte characters ...
    if (c < 0x800) {
      lastPos = i + 1;
      out += hexTable[0xc0 | (c >> 6)] + hexTable[0x80 | (c & 0x3f)];
      continue;
    }
    if (c < 0xd800 || c >= 0xe000) {
      lastPos = i + 1;
      out += hexTable[0xe0 | (c >> 12)] +
        hexTable[0x80 | ((c >> 6) & 0x3f)] +
        hexTable[0x80 | (c & 0x3f)];
      continue;
    }
    // Surrogate pair
    ++i;

    // This branch should never happen because all URLSearchParams entries
    // should already be converted to USVString. But, included for
    // completion's sake anyway.
    if (i >= len) throw new ERR_INVALID_URI();

    const c2 = str.charCodeAt(i) & 0x3ff;

    lastPos = i + 1;
    c = 0x10000 + (((c & 0x3ff) << 10) | c2);
    out += hexTable[0xf0 | (c >> 18)] +
      hexTable[0x80 | ((c >> 12) & 0x3f)] +
      hexTable[0x80 | ((c >> 6) & 0x3f)] +
      hexTable[0x80 | (c & 0x3f)];
  }
  if (lastPos === 0) return str;
  if (lastPos < len) return out + str.slice(lastPos);
  return out;
}

export default {
  hexTable,
  encodeStr,
  isHexTable,
};