export function isUndefined(value: unknown): value is undefined {
  return typeof value === "undefined";
}

export function isNil(value: unknown): value is null | undefined {
  return value === null || isUndefined(value);
}

export function isArray<T>(value: unknown): value is T[] {
  return Array.isArray(value);
}

export function isObject(value: unknown): value is object {
  return typeof value === "object" && value !== null && !isArray(value);
}

export function isString(value: unknown): value is string {
  return typeof value === "string";
}

export function isFunction(value: unknown): value is Function {
  return typeof value === "function";
}

export function isBoolean(value: unknown): value is boolean {
  return typeof value === "boolean";
}

export function isEmpty(value: any): boolean {
  if (isArray(value)) {
    return value.length === 0;
  } else if (isObject(value)) {
    return Object.keys(value).length === 0;
  } else {
    return !value;
  }
}

export function forEach<T>(obj: T, fn: (key: keyof T, value: T[keyof T], obj: T) => void): void {
  if (isUndefined(obj)) {
    return;
  }

  if (isArray(obj)) {
    obj.forEach(function (value, index) {
      fn.call(null, index, value, obj);
    });
  } else {
    for (const key in obj) {
      fn.call(null, key, obj[key], obj);
    }
  }
}

export function ensureLeadingToken(value: string, token: string): string {
  if (!value.startsWith(token)) {
    return `${token}${value}`;
  }

  return value;
}

export function ensureTrailingToken(value: string, token: string): string {
  if (!value.endsWith(token)) {
    return `${value}${token}`;
  }

  return value;
}

export function removeFileExtension(value: string): string {
  return value.replace(/\.[^/.]+$/, "");
}

export function getCurrentWorkingEnvironment(): string {
  return process.env.NODE_ENV || "development";
}

export async function asyncReduce<T, U>(
  array: T[],
  callback: (accumulator: U, current: T) => Promise<U>,
  initialValue: U
): Promise<U> {
  let accumulator = initialValue;

  for (const current of array) {
    accumulator = await callback(accumulator, current);
  }

  return accumulator;
}