// Copyright © Aptos Foundation
// SPDX-License-Identifier: Apache-2.0

import { MoveFunctionId, MoveStructId } from "../types/index.js";
import { AccountAddress } from "../core/accountAddress.js";
import { createObjectAddress } from "../core/account/utils/address.js";
import { TEXT_ENCODER } from "./const.js";

/**
 * Maximum bigint value that can be losslessly converted to a JS `number`.
 * Equal to `BigInt(Number.MAX_SAFE_INTEGER)` (2^53 - 1).
 */
const MAX_SAFE_U64 = BigInt(Number.MAX_SAFE_INTEGER);

/**
 * Narrows a u64 (`bigint`) into a JS `number` with an explicit safety check.
 *
 * The `deserializeU64` reader returns `bigint`, but several keyless code
 * paths historically narrowed the value with `Number(value)` to fit existing
 * `number`-typed fields (expiry timestamps, expiry horizons). For values
 * larger than `Number.MAX_SAFE_INTEGER` (~9 × 10^15), `Number(bigint)`
 * silently loses precision — comparisons against `Date.now() / 1000` then
 * return wrong results.
 *
 * Real-world expiry values are far below the unsafe range (year ~285 million
 * AD as a Unix timestamp), so this check is effectively a guard against
 * corrupted or malicious BCS data rather than a precision concern in normal
 * operation. Throwing is correct behavior at the BCS/JSON boundary.
 */
export function u64ToNumberSafe(value: bigint, fieldName: string): number {
  if (value < 0n) {
    throw new RangeError(`${fieldName} is negative (${value}); expected an unsigned u64`);
  }
  if (value > MAX_SAFE_U64) {
    throw new RangeError(
      `${fieldName} (${value}) exceeds Number.MAX_SAFE_INTEGER (${MAX_SAFE_U64}); refusing to silently lose precision`,
    );
  }
  return Number(value);
}

/**
 * Checks if the current runtime environment is Bun.
 * This is useful for detecting Bun-specific compatibility issues.
 *
 * @returns true if running in Bun, false otherwise.
 * @group Implementation
 * @category Utils
 */
export function isBun(): boolean {
  try {
    // Bun exposes a global `Bun` object.
    return typeof globalThis !== "undefined" && "Bun" in globalThis;
  } catch {
    return false;
  }
}

/**
 * Read an environment variable in a runtime-agnostic way. Returns `undefined` when
 * `process.env` is not available (browsers, some bundlers) or the variable is unset.
 *
 * @group Implementation
 * @category Utils
 */
export function getEnvVar(name: string): string | undefined {
  return typeof process !== "undefined" ? process.env?.[name] : undefined;
}

/**
 * Logs a warning message to the console only in development environments.
 * This function helps reduce information leakage in production while maintaining
 * helpful warnings during development.
 *
 * @param message - The warning message to log.
 * @group Implementation
 * @category Utils
 */
export function warnIfDevelopment(message: string): void {
  // Check common environment variables to determine if we're in development
  // This works in Node.js, bundlers like webpack/vite, and most build systems
  const isDevelopment =
    typeof process !== "undefined" &&
    process.env &&
    (process.env.NODE_ENV === "development" ||
      process.env.NODE_ENV === "test" ||
      process.env.APTOS_SDK_WARNINGS === "true");

  if (isDevelopment) {
    console.warn(message);
  }
}

/**
 * Sleep for the specified amount of time in milliseconds.
 * This function can be used to introduce delays in asynchronous operations.
 *
 * @param timeMs - The time in milliseconds to sleep.
 * @group Implementation
 * @category Utils
 */
export async function sleep(timeMs: number): Promise<void> {
  return new Promise((resolve) => {
    setTimeout(resolve, timeMs);
  });
}

/**
 * Get the error message from an unknown error.
 *
 * @param error The error to get the message from
 * @returns The error message
 * @group Implementation
 * @category Utils
 */
export function getErrorMessage(error: unknown): string {
  return error instanceof Error ? error.message : String(error);
}

/**
 * @group Implementation
 * @category Utils
 */
export const nowInSeconds = () => Math.floor(Date.now() / 1000);

/**
 * Floors the given timestamp to the nearest whole hour.
 * This function is useful for normalizing timestamps to hourly intervals.
 *
 * @param timestampInSeconds - The timestamp in seconds to be floored.
 * @group Implementation
 * @category Utils
 */
export function floorToWholeHour(timestampInSeconds: number): number {
  const date = new Date(timestampInSeconds * 1000);
  // Reset minutes and seconds to zero
  date.setMinutes(0);
  date.setSeconds(0);
  date.setMilliseconds(0);
  return Math.floor(date.getTime() / 1000);
}

/**
 * Decodes a base64 URL-encoded string into its original form.
 * This function is useful for converting base64 URL-encoded data back to a readable format.
 *
 * @param base64Url - The base64 URL-encoded string to decode.
 * @returns The decoded string.
 * @group Implementation
 * @category Utils
 */
export function base64UrlDecode(base64Url: string): string {
  // Decode the bytes, then interpret as UTF-8. `atob` alone returns a Latin-1 binary
  // string which corrupts any non-ASCII characters in JWT headers/payloads.
  return new TextDecoder("utf-8").decode(base64UrlToBytes(base64Url));
}

/**
 * Encode a string or byte array as a base64url string (RFC 4648 §5) with no padding.
 *
 * @param input - The data to encode. Strings are interpreted as UTF-8.
 * @returns The base64url-encoded string.
 * @group Implementation
 * @category Utils
 */
export function base64UrlEncode(input: string | Uint8Array): string {
  const bytes = typeof input === "string" ? TEXT_ENCODER.encode(input) : input;
  // btoa requires a Latin-1 string. Build it in chunks of 8 KiB so we avoid
  // `String.fromCharCode(...hugeArray)` call-stack overflows while still
  // keeping conversion linear-time (concatenating per-byte is O(n^2) in many
  // engines).
  const CHUNK = 0x8000;
  let binary = "";
  if (bytes.length <= CHUNK) {
    binary = String.fromCharCode.apply(null, bytes as unknown as number[]);
  } else {
    const parts: string[] = [];
    for (let i = 0; i < bytes.length; i += CHUNK) {
      const chunk = bytes.subarray(i, i + CHUNK);
      parts.push(String.fromCharCode.apply(null, chunk as unknown as number[]));
    }
    binary = parts.join("");
  }
  return btoa(binary).replace(/\+/g, "-").replace(/\//g, "_").replace(/=+$/, "");
}

export function base64UrlToBytes(base64Url: string): Uint8Array {
  // Convert base64url to standard base64, then decode with universal atob.
  // Standard base64 encodes 3 bytes as 4 chars, so the decoded input length
  // must be a multiple of 4 — pad with `=` based on `length % 4`.
  const base64 = base64Url.replace(/-/g, "+").replace(/_/g, "/");
  const padded = base64 + "===".substring(0, (4 - (base64.length % 4)) % 4);
  const binary = atob(padded);
  const bytes = new Uint8Array(binary.length);
  for (let i = 0; i < binary.length; i++) {
    bytes[i] = binary.charCodeAt(i);
  }
  return bytes;
}

/**
 * Amount is represented in the smallest unit format on chain, this function converts
 * a human-readable amount format to the smallest unit format
 * @example
 * human-readable amount format: 500
 * on chain amount format when decimal is 8: 50000000000
 *
 * @param value The value in human-readable format
 * @param decimal The token decimal
 * @returns The value in the smallest units
 * @group Implementation
 * @category Utils
 */
export const convertAmountFromHumanReadableToOnChain = (value: number, decimal: number) => value * 10 ** decimal;

/**
 * Amount is represented in the smallest unit format on chain, this function converts
 * the smallest unit format to a human-readable amount format
 * @example
 * human-readable amount format: 500
 * on chain amount format when decimal is 8: 50000000000
 *
 * @param value The value in human-readable format
 * @param decimal The token decimal
 * @returns The value in the smallest units
 * @group Implementation
 * @category Utils
 */
export const convertAmountFromOnChainToHumanReadable = (value: number, decimal: number) => value / 10 ** decimal;

/**
 * Convert a hex string to an ascii string with the `0x` prefix.
 *
 * `0x6170746f735f636f696e` --> `aptos_coin`
 *
 * @param hex The hex string to convert (e.g. `0x6170746f735f636f696e`)
 * @returns The ascii string
 * @group Implementation
 * @category Utils
 */
const hexToAscii = (hex: string) => {
  let str = "";
  for (let n = 2; n < hex.length; n += 2) {
    str += String.fromCharCode(parseInt(hex.substring(n, n + 2), 16));
  }
  return str;
};

/**
 * Convert an encoded struct to a MoveStructId.
 *
 * @example
 * const structObj = {
 *   account_address: "0x1",
 *   module_name: "0x6170746f735f636f696e",
 *   struct_name: "0x4170746f73436f696e",
 * };
 * // structId is "0x1::aptos_coin::AptosCoin"
 * const structId = parseEncodedStruct(structObj);
 *
 * @param structObj The struct with account_address, module_name, and struct_name properties
 * @returns The MoveStructId
 * @group Implementation
 * @category Utils
 */
export const parseEncodedStruct = (structObj: {
  account_address: string;
  module_name: string;
  struct_name: string;
}): MoveStructId => {
  const { account_address, module_name, struct_name } = structObj;
  const moduleName = hexToAscii(module_name);
  const structName = hexToAscii(struct_name);
  return `${account_address}::${moduleName}::${structName}`;
};

/**
 * Determines whether the given object is an encoded struct type with the following properties:
 * - account_address: string
 * - module_name: string
 * - struct_name: string
 *
 * @param structObj The object to check
 * @returns Whether the object is an encoded struct type
 * @group Implementation
 * @category Utils
 */
export const isEncodedStruct = (
  structObj: any,
): structObj is {
  account_address: string;
  module_name: string;
  struct_name: string;
} =>
  typeof structObj === "object" &&
  !Array.isArray(structObj) &&
  structObj !== null &&
  "account_address" in structObj &&
  "module_name" in structObj &&
  "struct_name" in structObj &&
  typeof structObj.account_address === "string" &&
  typeof structObj.module_name === "string" &&
  typeof structObj.struct_name === "string";

/**
 * Splits a function identifier into its constituent parts: module address, module name, and function name.
 * This function helps in validating and extracting details from a function identifier string.
 *
 * @param functionArg - The function identifier string in the format "moduleAddress::moduleName::functionName".
 * @returns An object containing the module address, module name, and function name.
 * @throws Error if the function identifier does not contain exactly three parts.
 * @group Implementation
 * @category Transactions
 */
export function getFunctionParts(functionArg: MoveFunctionId) {
  const funcNameParts = functionArg.split("::");
  if (funcNameParts.length !== 3) {
    throw new Error(`Invalid function ${functionArg}`);
  }
  const moduleAddress = funcNameParts[0];
  const moduleName = funcNameParts[1];
  const functionName = funcNameParts[2];
  return { moduleAddress, moduleName, functionName };
}

/**
 * Validates the provided function information.
 *
 * @param functionInfo - The function information to validate.
 * @returns Whether the function information is valid.
 * @group Implementation
 * @category Utils
 */
export function isValidFunctionInfo(functionInfo: string): boolean {
  const parts = functionInfo.split("::");
  return parts.length === 3 && AccountAddress.isValid({ input: parts[0] }).valid;
}

/**
 * Truncates the provided wallet address at the middle with an ellipsis.
 *
 * @param address - The wallet address to truncate.
 * @param start - The number of characters to show at the beginning of the address.
 * @param end - The number of characters to show at the end of the address.
 * @returns The truncated address.
 * @group Implementation
 * @category Utils
 */
export function truncateAddress(address: string, start: number = 6, end: number = 5) {
  return `${address.slice(0, start)}...${address.slice(-end)}`;
}

/**
 * Constants for metadata address calculation
 */
const APTOS_COIN_TYPE_STR = "0x1::aptos_coin::AptosCoin";

/**
 * Helper function to standardize Move type string by converting all addresses to short form,
 * including addresses within nested type parameters
 */
function standardizeMoveTypeString(input: string): string {
  // Regular expression to match addresses in the type string, including those within type parameters
  // This regex matches "0x" followed by hex digits, handling both standalone addresses and those within <>
  const addressRegex = /0x[0-9a-fA-F]+/g;

  return input.replace(addressRegex, (match) =>
    // Use AccountAddress to handle the address
    AccountAddress.from(match, { maxMissingChars: 63 }).toStringShort(),
  );
}

/**
 * Calculates the paired FA metadata address for a given coin type.
 * This function is tolerant of various address formats in the coin type string,
 * including complex nested types.
 *
 * @example
 * // All these formats are valid and will produce the same result:
 * pairedFaMetadataAddress("0x1::aptos_coin::AptosCoin")  // simple form
 * pairedFaMetadataAddress("0x0000000000000000000000000000000000000000000000000000000000000001::aptos_coin::AptosCoin")  // long form
 * pairedFaMetadataAddress("0x00001::aptos_coin::AptosCoin")  // with leading zeros
 * pairedFaMetadataAddress("0x1::coin::Coin<0x1412::a::struct<0x0001::aptos_coin::AptosCoin>>")  // nested type parameters
 *
 * @param coinType - The coin type string in any of these formats:
 *   - Short form address: "0x1::aptos_coin::AptosCoin"
 *   - Long form address: "0x0000000000000000000000000000000000000000000000000000000000000001::aptos_coin::AptosCoin"
 *   - With leading zeros: "0x00001::aptos_coin::AptosCoin"
 *   - With nested types: "0x1::coin::Coin<0x1412::a::struct<0x0001::aptos_coin::AptosCoin>>"
 * @returns The calculated metadata address as an AccountAddress instance
 */
export function pairedFaMetadataAddress(coinType: `0x${string}::${string}::${string}`): AccountAddress {
  // Standardize the coin type string to handle any address format
  const standardizedMoveTypeName = standardizeMoveTypeString(coinType);

  return standardizedMoveTypeName === APTOS_COIN_TYPE_STR
    ? AccountAddress.A
    : createObjectAddress(AccountAddress.A, standardizedMoveTypeName);
}