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// Copyright © 2026 Mikhail Hogrefe
//
// This file is part of Malachite.
//
// Malachite is free software: you can redistribute it and/or modify it under the terms of the GNU
// Lesser General Public License (LGPL) as published by the Free Software Foundation; either version
// 3 of the License, or (at your option) any later version. See <https://www.gnu.org/licenses/>.
use crate::integer::Integer;
use crate::natural::Natural;
use malachite_base::num::arithmetic::traits::{Abs, AbsAssign, UnsignedAbs};
impl Abs for Integer {
type Output = Self;
/// Takes the absolute value of an [`Integer`], taking the [`Integer`] by value.
///
/// $$
/// f(x) = |x|.
/// $$
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// ```
/// use malachite_base::num::arithmetic::traits::Abs;
/// use malachite_base::num::basic::traits::Zero;
/// use malachite_nz::integer::Integer;
///
/// assert_eq!(Integer::ZERO.abs(), 0);
/// assert_eq!(Integer::from(123).abs(), 123);
/// assert_eq!(Integer::from(-123).abs(), 123);
/// ```
#[inline]
fn abs(mut self) -> Self {
self.sign = true;
self
}
}
impl Abs for &Integer {
type Output = Integer;
/// Takes the absolute value of an [`Integer`], taking the [`Integer`] by reference.
///
/// $$
/// f(x) = |x|.
/// $$
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(n)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `self.significant_bits()`.
///
/// # Examples
/// ```
/// use malachite_base::num::arithmetic::traits::Abs;
/// use malachite_base::num::basic::traits::Zero;
/// use malachite_nz::integer::Integer;
///
/// assert_eq!((&Integer::ZERO).abs(), 0);
/// assert_eq!((&Integer::from(123)).abs(), 123);
/// assert_eq!((&Integer::from(-123)).abs(), 123);
/// ```
fn abs(self) -> Integer {
Integer {
sign: true,
abs: self.abs.clone(),
}
}
}
impl AbsAssign for Integer {
/// Replaces an [`Integer`] with its absolute value.
///
/// $$
/// x \gets |x|.
/// $$
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// ```
/// use malachite_base::num::arithmetic::traits::AbsAssign;
/// use malachite_base::num::basic::traits::Zero;
/// use malachite_nz::integer::Integer;
///
/// let mut x = Integer::ZERO;
/// x.abs_assign();
/// assert_eq!(x, 0);
///
/// let mut x = Integer::from(123);
/// x.abs_assign();
/// assert_eq!(x, 123);
///
/// let mut x = Integer::from(-123);
/// x.abs_assign();
/// assert_eq!(x, 123);
/// ```
#[inline]
fn abs_assign(&mut self) {
self.sign = true;
}
}
impl UnsignedAbs for Integer {
type Output = Natural;
/// Takes the absolute value of an [`Integer`], taking the [`Integer`] by value and converting
/// the result to a [`Natural`].
///
/// $$
/// f(x) = |x|.
/// $$
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// ```
/// use malachite_base::num::arithmetic::traits::UnsignedAbs;
/// use malachite_base::num::basic::traits::Zero;
/// use malachite_nz::integer::Integer;
///
/// assert_eq!(Integer::ZERO.unsigned_abs(), 0);
/// assert_eq!(Integer::from(123).unsigned_abs(), 123);
/// assert_eq!(Integer::from(-123).unsigned_abs(), 123);
/// ```
#[inline]
fn unsigned_abs(self) -> Natural {
self.abs
}
}
impl UnsignedAbs for &Integer {
type Output = Natural;
/// Takes the absolute value of an [`Integer`], taking the [`Integer`] by reference and
/// converting the result to a [`Natural`].
///
/// $$
/// f(x) = |x|.
/// $$
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(n)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `self.significant_bits()`.
///
/// # Examples
/// ```
/// use malachite_base::num::arithmetic::traits::UnsignedAbs;
/// use malachite_base::num::basic::traits::Zero;
/// use malachite_nz::integer::Integer;
///
/// assert_eq!((&Integer::ZERO).unsigned_abs(), 0);
/// assert_eq!((&Integer::from(123)).unsigned_abs(), 123);
/// assert_eq!((&Integer::from(-123)).unsigned_abs(), 123);
/// ```
#[inline]
fn unsigned_abs(self) -> Natural {
self.abs.clone()
}
}
impl Integer {
/// Finds the absolute value of an [`Integer`], taking the [`Integer`] by reference and
/// returning a reference to the internal [`Natural`] absolute value.
///
/// $$
/// f(x) = |x|.
/// $$
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// ```
/// use malachite_base::num::basic::traits::Zero;
/// use malachite_nz::integer::Integer;
///
/// assert_eq!(*Integer::ZERO.unsigned_abs_ref(), 0);
/// assert_eq!(*Integer::from(123).unsigned_abs_ref(), 123);
/// assert_eq!(*Integer::from(-123).unsigned_abs_ref(), 123);
/// ```
#[inline]
pub const fn unsigned_abs_ref(&self) -> &Natural {
&self.abs
}
/// Mutates the absolute value of an [`Integer`] using a provided closure, and then returns
/// whatever the closure returns.
///
/// This function is similar to the [`unsigned_abs_ref`](Integer::unsigned_abs_ref) function,
/// which returns a reference to the absolute value. A function that returns a _mutable_
/// reference would be too dangerous, as it could leave the [`Integer`] in an invalid state
/// (specifically, with a negative sign but a zero absolute value). So rather than returning a
/// mutable reference, this function allows mutation of the absolute value using a closure.
/// After the closure executes, this function ensures that the [`Integer`] remains valid.
///
/// There is only constant time and memory overhead on top of the time and memory used by the
/// closure.
///
/// # Examples
/// ```
/// use malachite_base::num::arithmetic::traits::DivAssignMod;
/// use malachite_base::num::basic::traits::Two;
/// use malachite_nz::integer::Integer;
/// use malachite_nz::natural::Natural;
///
/// let mut n = Integer::from(-123);
/// let remainder = n.mutate_unsigned_abs(|x| x.div_assign_mod(Natural::TWO));
/// assert_eq!(n, -61);
/// assert_eq!(remainder, 1);
///
/// let mut n = Integer::from(-123);
/// n.mutate_unsigned_abs(|x| *x >>= 10);
/// assert_eq!(n, 0);
/// ```
pub fn mutate_unsigned_abs<F: FnOnce(&mut Natural) -> T, T>(&mut self, f: F) -> T {
let out = f(&mut self.abs);
if !self.sign && self.abs == 0 {
self.sign = true;
}
out
}
}