mat4 0.2.1

use core::ops::{Add, Div, Mul, Neg, Sub};

use num_traits::{Float, FromPrimitive, One, Zero};

use super::new_identity;

/// # Example
/// ```
/// let mut m = mat4::new_identity::<f32>();
/// mat4::look_at(&mut m, &[0_f32, 0_f32, 1_f32], &[0_f32, 0_f32, 0_f32], &[0_f32, 0_f32, 1_f32]);
/// assert_eq!(m, [
///     0_f32, 0_f32, 0_f32, 0_f32,
///     0_f32, 0_f32, 0_f32, 0_f32,
///     0_f32, 0_f32, 1_f32, 0_f32,
///     0_f32, 0_f32, -1_f32, 1_f32
/// ]);
/// ```
#[inline]
pub fn look_at<'out, T>(
    out: &'out mut [T; 16],
    eye: &[T; 3],
    target: &[T; 3],
    up: &[T; 3],
) -> &'out mut [T; 16]
where
    T: Clone + Zero + One + Float + Add<T, Output = T> + Sub<T, Output = T>,
    for<'a, 'b> &'a T: Mul<&'b T, Output = T>
        + Div<&'b T, Output = T>
        + Add<&'b T, Output = T>
        + Sub<&'b T, Output = T>,
{
    let eyex = &eye[0];
    let eyey = &eye[1];
    let eyez = &eye[2];
    let upx = &up[0];
    let upy = &up[1];
    let upz = &up[2];
    let targetx = &target[0];
    let targety = &target[1];
    let targetz = &target[2];

    let mut z0 = eyex - targetx;
    let mut z1 = eyey - targety;
    let mut z2 = eyez - targetz;
    let mut len = &z0 * &z0 + &z1 * &z1 + &z2 * &z2;

    if len.is_zero() {
        z0 = T::zero();
        z1 = T::zero();
        z2 = T::one();
    } else {
        len = &T::one() / &len.sqrt();
        z0 = &z0 * &len;
        z1 = &z1 * &len;
        z2 = &z2 * &len;
    }

    let mut x0 = upy * &z2 - upz * &z1;
    let mut x1 = upz * &z0 - upx * &z2;
    let mut x2 = upx * &z1 - upy * &z0;
    len = &x0 * &x0 + &x1 * &x1 + &x2 * &x2;

    if len.is_zero() {
        x0 = T::zero();
        x1 = T::zero();
        x2 = T::zero();
    } else {
        len = &T::one() / &len.sqrt();
        x0 = &x0 * &len;
        x1 = &x1 * &len;
        x2 = &x2 * &len;
    }

    let mut y0 = &z1 * &x2 - &z2 * &x1;
    let mut y1 = &z2 * &x0 - &z0 * &x2;
    let mut y2 = &z0 * &x1 - &z1 * &x0;
    len = &y0 * &y0 + &y1 * &y1 + &y2 * &y2;

    if len.is_zero() {
        y0 = T::zero();
        y1 = T::zero();
        y2 = T::zero();
    } else {
        len = &T::one() / &len.sqrt();
        y0 = &y0 * &len;
        y1 = &y1 * &len;
        y2 = &y2 * &len;
    }

    out[0] = x0.clone();
    out[1] = x1.clone();
    out[2] = x2.clone();
    out[3] = T::zero();

    out[4] = y0.clone();
    out[5] = y1.clone();
    out[6] = y2.clone();
    out[7] = T::zero();

    out[8] = z0.clone();
    out[9] = z1.clone();
    out[10] = z2.clone();
    out[11] = T::zero();

    out[12] = -(&x0 * eyex + &x1 * eyey + &x2 * eyez);
    out[13] = -(&y0 * eyex + &y1 * eyey + &y2 * eyez);
    out[14] = -(&z0 * eyex + &z1 * eyey + &z2 * eyez);
    out[15] = T::one();

    out
}

#[inline]
pub fn translate<'out, T>(out: &'out mut [T; 16], a: &[T; 16], v: &[T; 3]) -> &'out mut [T; 16]
where
    T: Clone + Add<T, Output = T>,
    for<'a, 'b> &'a T: Mul<&'b T, Output = T>,
{
    let x = &v[0];
    let y = &v[1];
    let z = &v[2];
    let a00 = &a[0];
    let a01 = &a[1];
    let a02 = &a[2];
    let a03 = &a[3];
    let a10 = &a[4];
    let a11 = &a[5];
    let a12 = &a[6];
    let a13 = &a[7];
    let a20 = &a[8];
    let a21 = &a[9];
    let a22 = &a[10];
    let a23 = &a[11];

    out[0] = a00.clone();
    out[1] = a01.clone();
    out[2] = a02.clone();
    out[3] = a03.clone();
    out[4] = a10.clone();
    out[5] = a11.clone();
    out[6] = a12.clone();
    out[7] = a13.clone();
    out[8] = a20.clone();
    out[9] = a21.clone();
    out[10] = a22.clone();
    out[11] = a23.clone();

    out[12] = a00 * x + a10 * y + a20 * z + a[12].clone();
    out[13] = a01 * x + a11 * y + a21 * z + a[13].clone();
    out[14] = a02 * x + a12 * y + a22 * z + a[14].clone();
    out[15] = a03 * x + a13 * y + a23 * z + a[15].clone();
    out
}

#[inline]
pub fn scale<'out, T>(out: &'out mut [T; 16], a: &[T; 16], v: &[T; 3]) -> &'out mut [T; 16]
where
    T: Clone,
    for<'a, 'b> &'a T: Mul<&'b T, Output = T>,
{
    let x = &v[0];
    let y = &v[1];
    let z = &v[2];

    out[0] = &a[0] * x;
    out[1] = &a[1] * x;
    out[2] = &a[2] * x;
    out[3] = &a[3] * x;
    out[4] = &a[4] * y;
    out[5] = &a[5] * y;
    out[6] = &a[6] * y;
    out[7] = &a[7] * y;
    out[8] = &a[8] * z;
    out[9] = &a[9] * z;
    out[10] = &a[10] * z;
    out[11] = &a[11] * z;
    out[12] = a[12].clone();
    out[13] = a[13].clone();
    out[14] = a[14].clone();
    out[15] = a[15].clone();
    out
}

#[inline]
pub fn rotate_x<'out, T>(out: &'out mut [T; 16], a: &[T; 16], angle: &T) -> &'out mut [T; 16]
where
    T: Clone + Float + Add<T, Output = T> + Sub<T, Output = T>,
    for<'a, 'b> &'a T: Mul<&'b T, Output = T>,
{
    let s = angle.sin();
    let c = angle.cos();
    let a10 = &a[4];
    let a11 = &a[5];
    let a12 = &a[6];
    let a13 = &a[7];
    let a20 = &a[8];
    let a21 = &a[9];
    let a22 = &a[10];
    let a23 = &a[11];

    out[0] = a[0].clone();
    out[1] = a[1].clone();
    out[2] = a[2].clone();
    out[3] = a[3].clone();
    out[12] = a[12].clone();
    out[13] = a[13].clone();
    out[14] = a[14].clone();
    out[15] = a[15].clone();
    out[4] = a10 * &c + a20 * &s;
    out[5] = a11 * &c + a21 * &s;
    out[6] = a12 * &c + a22 * &s;
    out[7] = a13 * &c + a23 * &s;
    out[8] = a20 * &c - a10 * &s;
    out[9] = a21 * &c - a11 * &s;
    out[10] = a22 * &c - a12 * &s;
    out[11] = a23 * &c - a13 * &s;
    out
}

#[inline]
pub fn rotate_y<'out, T>(out: &'out mut [T; 16], a: &[T; 16], angle: &T) -> &'out mut [T; 16]
where
    T: Clone + Float + Add<T, Output = T> + Sub<T, Output = T>,
    for<'a, 'b> &'a T: Mul<&'b T, Output = T>,
{
    let s = angle.sin();
    let c = angle.cos();
    let a00 = &a[0];
    let a01 = &a[1];
    let a02 = &a[2];
    let a03 = &a[3];
    let a20 = &a[8];
    let a21 = &a[9];
    let a22 = &a[10];
    let a23 = &a[11];

    out[4] = a[4].clone();
    out[5] = a[5].clone();
    out[6] = a[6].clone();
    out[7] = a[7].clone();
    out[12] = a[12].clone();
    out[13] = a[13].clone();
    out[14] = a[14].clone();
    out[15] = a[15].clone();
    out[0] = a00 * &c - a20 * &s;
    out[1] = a01 * &c - a21 * &s;
    out[2] = a02 * &c - a22 * &s;
    out[3] = a03 * &c - a23 * &s;
    out[8] = a00 * &s + a20 * &c;
    out[9] = a01 * &s + a21 * &c;
    out[10] = a02 * &s + a22 * &c;
    out[11] = a03 * &s + a23 * &c;
    out
}

#[inline]
pub fn rotate_z<'out, T>(out: &'out mut [T; 16], a: &[T; 16], angle: &T) -> &'out mut [T; 16]
where
    T: Clone + Float + Add<T, Output = T> + Sub<T, Output = T>,
    for<'a, 'b> &'a T: Mul<&'b T, Output = T>,
{
    let s = angle.sin();
    let c = angle.cos();
    let a00 = &a[0];
    let a01 = &a[1];
    let a02 = &a[2];
    let a03 = &a[3];
    let a10 = &a[4];
    let a11 = &a[5];
    let a12 = &a[6];
    let a13 = &a[7];

    out[8] = a[8].clone();
    out[9] = a[9].clone();
    out[10] = a[10].clone();
    out[11] = a[11].clone();
    out[12] = a[12].clone();
    out[13] = a[13].clone();
    out[14] = a[14].clone();
    out[15] = a[15].clone();
    out[0] = a00 * &c + a10 * &s;
    out[1] = a01 * &c + a11 * &s;
    out[2] = a02 * &c + a12 * &s;
    out[3] = a03 * &c + a13 * &s;
    out[4] = a10 * &c - a00 * &s;
    out[5] = a11 * &c - a01 * &s;
    out[6] = a12 * &c - a02 * &s;
    out[7] = a13 * &c - a03 * &s;
    out
}

#[inline]
pub fn rotate<'out, T>(
    out: &'out mut [T; 16],
    a: &[T; 16],
    x: &T,
    y: &T,
    z: &T,
) -> &'out mut [T; 16]
where
    T: Clone + Float + Add<T, Output = T> + Sub<T, Output = T>,
    for<'a, 'b> &'a T: Mul<&'b T, Output = T>,
{
    let mut tmp_a = a.clone();
    let mut tmp_b = new_identity();
    rotate_z(&mut tmp_a, a, z);
    rotate_x(&mut tmp_b, &tmp_a, x);
    rotate_y(out, &tmp_b, y);
    out
}

#[inline]
pub fn frustum<'out, T>(
    out: &'out mut [T; 16],
    top: &T,
    right: &T,
    bottom: &T,
    left: &T,
    near: &T,
    far: &T,
) -> &'out mut [T; 16]
where
    T: One + Zero + FromPrimitive + Neg<Output = T>,
    for<'a, 'b> &'a T: Neg<Output = T>
        + Mul<&'b T, Output = T>
        + Div<&'b T, Output = T>
        + Add<&'b T, Output = T>
        + Sub<&'b T, Output = T>,
{
    let x = &(&T::from_isize(2).unwrap() * near) / &(right - left);
    let y = &(&T::from_isize(2).unwrap() * near) / &(top - bottom);

    let a = &(right + left) / &(right - left);
    let b = &(top + bottom) / &(top - bottom);
    let c = &-&(far + near) / &(far - near);
    let d = &(&(&T::from_isize(-2).unwrap() * far) * near) / &(far - near);

    out[0] = x;
    out[4] = T::zero();
    out[8] = a;
    out[12] = T::zero();
    out[1] = T::zero();
    out[5] = y;
    out[9] = b;
    out[13] = T::zero();
    out[2] = T::zero();
    out[6] = T::zero();
    out[10] = c;
    out[14] = d;
    out[3] = T::zero();
    out[7] = T::zero();
    out[11] = -T::one();
    out[15] = T::zero();

    out
}

#[inline]
pub fn perspective<'out, T>(
    out: &'out mut [T; 16],
    fov: &T,
    aspect: &T,
    near: &T,
    far: &T,
) -> &'out mut [T; 16]
where
    T: One + Zero + Float + FromPrimitive + Neg<Output = T>,
    for<'a, 'b> &'a T: Neg<Output = T>
        + Mul<&'b T, Output = T>
        + Div<&'b T, Output = T>
        + Add<&'b T, Output = T>
        + Sub<&'b T, Output = T>,
{
    let ymax = near * &(fov / &T::from_isize(2).unwrap()).tan();
    let ymin = -ymax;
    let xmin = &ymin * aspect;
    let xmax = &ymax * aspect;

    frustum(out, &ymax, &xmax, &ymin, &xmin, near, far)
}

#[inline]
pub fn orthographic<'out, T>(
    out: &'out mut [T; 16],
    top: &T,
    right: &T,
    bottom: &T,
    left: &T,
    near: &T,
    far: &T,
) -> &'out mut [T; 16]
where
    T: One + Zero + FromPrimitive + Neg<Output = T>,
    for<'a, 'b> &'a T: Neg<Output = T>
        + Mul<&'b T, Output = T>
        + Div<&'b T, Output = T>
        + Add<&'b T, Output = T>
        + Sub<&'b T, Output = T>,
{
    let w = right - left;
    let h = top - bottom;
    let p = far - near;

    let x = &(right + left) / &w;
    let y = &(top + bottom) / &h;
    let z = &(far + near) / &p;

    out[0] = &T::from_isize(2).unwrap() / &w;
    out[1] = T::zero();
    out[2] = T::zero();
    out[3] = T::zero();
    out[4] = T::zero();
    out[5] = &T::from_isize(2).unwrap() / &h;
    out[6] = T::zero();
    out[7] = T::zero();
    out[8] = T::zero();
    out[9] = T::zero();
    out[10] = &T::from_isize(-2).unwrap() / &p;
    out[11] = T::zero();
    out[12] = -x;
    out[13] = -y;
    out[14] = -z;
    out[15] = T::one();

    out
}