//
// Basic geometric things...
//
// Georg Hopp <georg@steffers.org>
//
// Copyright © 2019 Georg Hopp
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
//

use std::fmt::Debug;
use std::ops::{Add, Div, Mul, Neg, Sub};

use crate::math::transform::{TMatrix, Transformable};
use crate::math::trigonometry::Trig;
use crate::math::vector::Vector;

#[derive(Debug, PartialEq, Eq, Clone, Copy)]
pub struct Point<T>(pub Vector<T>, T)
    where T: Add + Sub + Neg + Mul + Div + PartialEq + Copy + Trig;

impl<T> Point<T>
where T: Add<Output = T> + Sub<Output = T> + Neg<Output = T>
       + Mul<Output = T> + Div<Output = T>
       + PartialEq + Trig + Copy + From<i32> {
    pub fn new(x :T, y :T, z :T) -> Self {
        Self(Vector(x, y, z), 1.into())
    }
}

impl<T> Add for Point<T>
where T: Add<Output = T> + Sub<Output = T> + Neg<Output = T>
       + Mul<Output = T> + Div<Output = T>
       + PartialEq + Trig + Copy {
    type Output = Self;

    fn add(self, other :Self) -> Self {
        let Point(v1, w1) = self;
        let Point(v2, w2) = other;
        Self(v1 + v2, w1 + w2)
    }
}

impl<T> Neg for Point<T>
where T: Add<Output = T> + Sub<Output = T> + Neg<Output = T>
       + Mul<Output = T> + Div<Output = T>
       + PartialEq + Trig + Copy {
    type Output = Self;

    fn neg(self) -> Self {
        let Point(v, w) = self;
        Self(-v, -w)
    }
}

impl<T> Sub for Point<T>
where T: Add<Output = T> + Sub<Output = T> + Neg<Output = T>
       + Mul<Output = T> + Div<Output = T>
       + PartialEq + Trig + Copy {
    type Output = Self;

    fn sub(self, other :Self) -> Self {
        self + -other
    }
}

impl<T> Mul for Point<T>
where T: Add<Output = T> + Sub<Output = T> + Neg<Output = T>
       + Mul<Output = T> + Div<Output = T>
       + PartialEq + Trig + Copy + From<i32> {
    type Output = Self;

    fn mul(self, other :Self) -> Self {
        let a :Vector<T> = self.into();
        let b :Vector<T> = other.into();

        Point(a * b, 1.into())
    }
}

impl<T> From<Vector<T>> for Point<T>
where T: Add<Output = T> + Sub<Output = T> + Neg<Output = T>
       + Mul<Output = T> + Div<Output = T>
       + PartialEq + Trig + Copy + From<i32> {
    fn from(v :Vector<T>) -> Self {
        Point(v, 1.into())
    }
}

impl<T> Into<Vector<T>> for Point<T>
where T: Add<Output = T> + Sub<Output = T> + Neg<Output = T>
       + Mul<Output = T> + Div<Output = T>
       + PartialEq + Trig + Copy + From<i32> {
    fn into(self) -> Vector<T> {
        let Point(v, w) = self;

        if w == 0.into() {
            v
        } else {
            v.mul(&w.recip())
        }
    }
}

impl<T> Transformable<T> for Point<T>
where T: Add<Output = T> + Sub<Output = T> + Neg<Output = T>
       + Mul<Output = T> + Div<Output = T>
       + PartialEq + Debug + Trig + Copy + From<i32> {
    fn transform(&self, m :&TMatrix<T>) -> Self {
        let Point(v, w) = *self;
        let (v, w)      = m.apply(&v, w);

        if w == 0.into() {
            v.into()
        } else {
            v.mul(&w.recip()).into()
        }
    }
}