// Copyright 2013-2014 The CGMath Developers. For a full listing of the authors,
// refer to the AUTHORS file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use approx::ApproxEq;

use std::cmp;
use std::fmt;
use std::num::{Float, Int, NumCast};
use std::ops::*;

/// A trait providing a [partial ordering](http://mathworld.wolfram.com/PartialOrder.html).
pub trait PartialOrd {
    fn partial_min(self, other: Self) -> Self;
    fn partial_max(self, other: Self) -> Self;
}

macro_rules! partial_ord_int (
    ($T:ident) => (
        impl PartialOrd for $T {
            fn partial_min(self, other: $T) -> $T { cmp::min(self, other) }
            fn partial_max(self, other: $T) -> $T { cmp::max(self, other) }
        }
    )
);

partial_ord_int!(isize);
partial_ord_int!(i8);
partial_ord_int!(i16);
partial_ord_int!(i32);
partial_ord_int!(i64);
partial_ord_int!(usize);
partial_ord_int!(u8);
partial_ord_int!(u16);
partial_ord_int!(u32);
partial_ord_int!(u64);

macro_rules! partial_ord_float (
    ($T:ident) => (
        impl PartialOrd for $T {
            fn partial_min(self, other: $T) -> $T { self.min(other) }
            fn partial_max(self, other: $T) -> $T { self.max(other) }
        }
    )
);

partial_ord_float!(f32);
partial_ord_float!(f64);

/// Additive neutral element
pub trait Zero {
    fn zero() -> Self;
    fn is_zero(&self) -> bool;
}

/// Multiplicative neutral element
pub trait One {
    fn one() -> Self;
}

/// Base numeric types with partial ordering
pub trait BaseNum:
    Copy + NumCast + Clone + Add<Output=Self> + Sub<Output=Self> +
    Mul<Output=Self> + Div<Output=Self> + Rem<Output=Self> + Neg<Output=Self> + PartialEq
    + PartialOrd + cmp::PartialOrd + fmt::Debug + Zero + One
{}


macro_rules! impl_basenum_int (
    ($T: ident) => (
        impl BaseNum for $T {}
        impl Zero for $T {
            fn zero() -> $T {
                Int::zero()
            }

            fn is_zero(&self) -> bool {
                *self == Int::zero()
            }
        }

        impl One for $T {
            fn one() -> $T {
                Int::one()
            }
        }
    )
);

impl_basenum_int!(i8);
impl_basenum_int!(i16);
impl_basenum_int!(i32);
impl_basenum_int!(i64);
impl_basenum_int!(u8);
impl_basenum_int!(u16);
impl_basenum_int!(u32);
impl_basenum_int!(u64);
impl_basenum_int!(isize);
impl_basenum_int!(usize);


macro_rules! impl_basenum_float (
    ($T: ident) => (
        impl BaseNum for $T {}
        impl Zero for $T {
            fn zero() -> $T {
                Float::zero()
            }

            fn is_zero(&self) -> bool {
                *self == Float::zero()
            }
        }

        impl One for $T {
            fn one() -> $T {
                Float::one()
            }
        }
    )
);

impl_basenum_float!(f32);
impl_basenum_float!(f64);

pub fn zero<T: Zero>() -> T {
    Zero::zero()
}

pub fn one<T: One>() -> T {
    One::one()
}


/// Base integer types
pub trait BaseInt : BaseNum + Int {}

impl BaseInt for i8 {}
impl BaseInt for i16 {}
impl BaseInt for i32 {}
impl BaseInt for i64 {}
impl BaseInt for isize {}
impl BaseInt for u8 {}
impl BaseInt for u16 {}
impl BaseInt for u32 {}
impl BaseInt for u64 {}
impl BaseInt for usize {}

/// Base floating point types
pub trait BaseFloat : BaseNum + Float + ApproxEq<Self> {}

impl BaseFloat for f32 {}
impl BaseFloat for f64 {}