/**
 * Returns the and of two bools, but it evaluates both arguments.
 *
 * It's the function equivalent of the `&&` operator.
 * This function is useful in higher order functions or pipes.
 *
 * ## Examples
 *
 * ```gleam
 * and(True, True)
 * // -> True
 * ```
 *
 * ```gleam
 * and(False, True)
 * // -> False
 * ```
 *
 * ```gleam
 * False |> and(True)
 * // -> False
 * ```
 */
export function and(a, b) {
  return a && b;
}

/**
 * Returns the or of two bools, but it evaluates both arguments.
 *
 * It's the function equivalent of the `||` operator.
 * This function is useful in higher order functions or pipes.
 *
 * ## Examples
 *
 * ```gleam
 * or(True, True)
 * // -> True
 * ```
 *
 * ```gleam
 * or(False, True)
 * // -> True
 * ```
 *
 * ```gleam
 * False |> or(True)
 * // -> True
 * ```
 */
export function or(a, b) {
  return a || b;
}

/**
 * Returns the opposite bool value.
 *
 * This is the same as the `!` or `not` operators in some other languages.
 *
 * ## Examples
 *
 * ```gleam
 * negate(True)
 * // -> False
 * ```
 *
 * ```gleam
 * negate(False)
 * // -> True
 * ```
 */
export function negate(bool) {
  return !bool;
}

/**
 * Returns the nor of two bools.
 *
 * ## Examples
 *
 * ```gleam
 * nor(False, False)
 * // -> True
 * ```
 *
 * ```gleam
 * nor(False, True)
 * // -> False
 * ```
 *
 * ```gleam
 * nor(True, False)
 * // -> False
 * ```
 *
 * ```gleam
 * nor(True, True)
 * // -> False
 * ```
 */
export function nor(a, b) {
  return !(a || b);
}

/**
 * Returns the nand of two bools.
 *
 * ## Examples
 *
 * ```gleam
 * nand(False, False)
 * // -> True
 * ```
 *
 * ```gleam
 * nand(False, True)
 * // -> True
 * ```
 *
 * ```gleam
 * nand(True, False)
 * // -> True
 * ```
 *
 * ```gleam
 * nand(True, True)
 * // -> False
 * ```
 */
export function nand(a, b) {
  return !(a && b);
}

/**
 * Returns the exclusive or of two bools.
 *
 * ## Examples
 *
 * ```gleam
 * exclusive_or(False, False)
 * // -> False
 * ```
 *
 * ```gleam
 * exclusive_or(False, True)
 * // -> True
 * ```
 *
 * ```gleam
 * exclusive_or(True, False)
 * // -> True
 * ```
 *
 * ```gleam
 * exclusive_or(True, True)
 * // -> False
 * ```
 */
export function exclusive_or(a, b) {
  return a !== b;
}

/**
 * Returns the exclusive nor of two bools.
 *
 * ## Examples
 *
 * ```gleam
 * exclusive_nor(False, False)
 * // -> True
 * ```
 *
 * ```gleam
 * exclusive_nor(False, True)
 * // -> False
 * ```
 *
 * ```gleam
 * exclusive_nor(True, False)
 * // -> False
 * ```
 *
 * ```gleam
 * exclusive_nor(True, True)
 * // -> True
 * ```
 */
export function exclusive_nor(a, b) {
  return a === b;
}

/**
 * Returns a string representation of the given bool.
 *
 * ## Examples
 *
 * ```gleam
 * to_string(True)
 * // -> "True"
 * ```
 *
 * ```gleam
 * to_string(False)
 * // -> "False"
 * ```
 */
export function to_string(bool) {
  if (bool) {
    return "True";
  } else {
    return "False";
  }
}

/**
 * Run a callback function if the given bool is `False`, otherwise return a
 * default value.
 *
 * With a `use` expression this function can simulate the early-return pattern
 * found in some other programming languages.
 *
 * In a procedural language:
 *
 * ```js
 * if (predicate) return value;
 * // ...
 * ```
 *
 * In Gleam with a `use` expression:
 *
 * ```gleam
 * use <- guard(when: predicate, return: value)
 * // ...
 * ```
 *
 * Like everything in Gleam `use` is an expression, so it short circuits the
 * current block, not the entire function. As a result you can assign the value
 * to a variable:
 *
 * ```gleam
 * let x = {
 *   use <- guard(when: predicate, return: value)
 *   // ...
 * }
 * ```
 *
 * Note that unlike in procedural languages the `return` value is evaluated
 * even when the predicate is `False`, so it is advisable not to perform
 * expensive computation nor side-effects there.
 *
 *
 * ## Examples
 *
 * ```gleam
 * let name = ""
 * use <- guard(when: name == "", return: "Welcome!")
 * "Hello, " <> name
 * // -> "Welcome!"
 * ```
 *
 * ```gleam
 * let name = "Kamaka"
 * use <- guard(when: name == "", return: "Welcome!")
 * "Hello, " <> name
 * // -> "Hello, Kamaka"
 * ```
 */
export function guard(requirement, consequence, alternative) {
  if (requirement) {
    return consequence;
  } else {
    return alternative();
  }
}

/**
 * Runs a callback function if the given bool is `True`, otherwise runs an
 * alternative callback function.
 *
 * Useful when further computation should be delayed regardless of the given
 * bool's value.
 *
 * See [`guard`](#guard) for more info.
 *
 * ## Examples
 *
 * ```gleam
 * let name = "Kamaka"
 * let inquiry = fn() { "How may we address you?" }
 * use <- lazy_guard(when: name == "", return: inquiry)
 * "Hello, " <> name
 * // -> "Hello, Kamaka"
 * ```
 *
 * ```gleam
 * import gleam/int
 *
 * let name = ""
 * let greeting = fn() { "Hello, " <> name }
 * use <- lazy_guard(when: name == "", otherwise: greeting)
 * let number = int.random(99)
 * let name = "User " <> int.to_string(number)
 * "Welcome, " <> name
 * // -> "Welcome, User 54"
 * ```
 */
export function lazy_guard(requirement, consequence, alternative) {
  if (requirement) {
    return consequence();
  } else {
    return alternative();
  }
}