use num_traits::Float;

use std::marker::PhantomData;
use std::ops::{Add, Div, Mul, Sub};

use clamp;
use encoding::pixel::RawPixel;
use luma::LumaStandard;
use white_point::{D65, WhitePoint};
use {Alpha, Luma, Xyz};
use {Component, ComponentWise, IntoColor, Limited, Mix, Pixel, Shade};

/// CIE 1931 Yxy (xyY) with an alpha component. See the [`Yxya` implementation
/// in `Alpha`](struct.Alpha.html#Yxya).
pub type Yxya<Wp = D65, T = f32> = Alpha<Yxy<Wp, T>, T>;

///The CIE 1931 Yxy (xyY)  color space.
///
///Yxy is a luminance-chromaticity color space derived from the CIE XYZ
///color space. It is widely used to define colors. The chromacity diagrams
///for the color spaces are a plot of this color space's x and y coordiantes.
///
///Conversions and operations on this color space depend on the white point.
#[derive(Debug, PartialEq, FromColor, Pixel)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
#[palette_internal]
#[palette_white_point = "Wp"]
#[palette_component = "T"]
#[palette_manual_from(Xyz, Yxy, Luma)]
#[repr(C)]
pub struct Yxy<Wp = D65, T = f32>
where
    T: Component + Float,
    Wp: WhitePoint,
{
    ///x chromacity co-ordinate derived from XYZ color space as X/(X+Y+Z).
    ///Typical range is between 0 and 1
    pub x: T,

    ///y chromacity co-ordinate derived from XYZ color space as Y/(X+Y+Z).
    ///Typical range is between 0 and 1
    pub y: T,

    ///luma (Y) was a measure of the brightness or luminance of a color.
    ///It is the same as the Y from the XYZ color space. Its range is from
    ///0 to 1, where 0 is black and 1 is white.
    pub luma: T,

    ///The white point associated with the color's illuminant and observer.
    ///D65 for 2 degree observer is used by default.
    #[cfg_attr(feature = "serde", serde(skip))]
    #[palette_unsafe_zero_sized]
    pub white_point: PhantomData<Wp>,
}

impl<Wp, T> Copy for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
{
}

impl<Wp, T> Clone for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
{
    fn clone(&self) -> Yxy<Wp, T> {
        *self
    }
}

impl<T> Yxy<D65, T>
where
    T: Component + Float,
{
    ///CIE Yxy with white point D65.
    pub fn new(x: T, y: T, luma: T) -> Yxy<D65, T> {
        Yxy {
            x: x,
            y: y,
            luma: luma,
            white_point: PhantomData,
        }
    }
}

impl<Wp, T> Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
{
    ///CIE Yxy.
    pub fn with_wp(x: T, y: T, luma: T) -> Yxy<Wp, T> {
        Yxy {
            x: x,
            y: y,
            luma: luma,
            white_point: PhantomData,
        }
    }

    /// Convert to a `(x, y, luma)`, a.k.a. `(x, y, Y)` tuple.
    pub fn into_components(self) -> (T, T, T) {
        (self.x, self.y, self.luma)
    }

    /// Convert from a `(x, y, luma)`, a.k.a. `(x, y, Y)` tuple.
    pub fn from_components((x, y, luma): (T, T, T)) -> Self {
        Self::with_wp(x, y, luma)
    }
}

///<span id="Yxya"></span>[`Yxya`](type.Yxya.html) implementations.
impl<T, A> Alpha<Yxy<D65, T>, A>
where
    T: Component + Float,
    A: Component,
{
    ///CIE Yxy and transparency with white point D65.
    pub fn new(x: T, y: T, luma: T, alpha: A) -> Self {
        Alpha {
            color: Yxy::new(x, y, luma),
            alpha: alpha,
        }
    }
}
///<span id="Yxya"></span>[`Yxya`](type.Yxya.html) implementations.
impl<Wp, T, A> Alpha<Yxy<Wp, T>, A>
where
    T: Component + Float,
    A: Component,
    Wp: WhitePoint,
{
    ///CIE Yxy and transparency.
    pub fn with_wp(x: T, y: T, luma: T, alpha: A) -> Self {
        Alpha {
            color: Yxy::with_wp(x, y, luma),
            alpha: alpha,
        }
    }

    /// Convert to a `(x, y, luma)`, a.k.a. `(x, y, Y)` tuple.
    pub fn into_components(self) -> (T, T, T, A) {
        (self.x, self.y, self.luma, self.alpha)
    }

    /// Convert from a `(x, y, luma)`, a.k.a. `(x, y, Y)` tuple.
    pub fn from_components((x, y, luma, alpha): (T, T, T, A)) -> Self {
        Self::with_wp(x, y, luma, alpha)
    }
}

impl<Wp, T> From<Xyz<Wp, T>> for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
{
    fn from(xyz: Xyz<Wp, T>) -> Self {
        let mut yxy = Yxy {
            x: T::zero(),
            y: T::zero(),
            luma: xyz.y,
            white_point: PhantomData,
        };
        let sum = xyz.x + xyz.y + xyz.z;
        // If denominator is zero, NAN or INFINITE leave x and y at the default 0
        if sum.is_normal() {
            yxy.x = xyz.x / sum;
            yxy.y = xyz.y / sum;
        }
        yxy
    }
}

impl<S, T> From<Luma<S, T>> for Yxy<S::WhitePoint, T>
where
    T: Component + Float,
    S: LumaStandard,
{
    fn from(luma: Luma<S, T>) -> Self {
        Yxy {
            luma: luma.into_linear().luma,
            ..Default::default()
        }
    }
}

impl<Wp: WhitePoint, T: Component + Float> From<(T, T, T)> for Yxy<Wp, T> {
    fn from(components: (T, T, T)) -> Self {
        Self::from_components(components)
    }
}

impl<Wp: WhitePoint, T: Component + Float> Into<(T, T, T)> for Yxy<Wp, T> {
    fn into(self) -> (T, T, T) {
        self.into_components()
    }
}

impl<Wp: WhitePoint, T: Component + Float, A: Component> From<(T, T, T, A)>
    for Alpha<Yxy<Wp, T>, A>
{
    fn from(components: (T, T, T, A)) -> Self {
        Self::from_components(components)
    }
}

impl<Wp: WhitePoint, T: Component + Float, A: Component> Into<(T, T, T, A)>
    for Alpha<Yxy<Wp, T>, A>
{
    fn into(self) -> (T, T, T, A) {
        self.into_components()
    }
}

impl<Wp, T> Limited for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
{
    #[cfg_attr(rustfmt, rustfmt_skip)]
    fn is_valid(&self) -> bool {
        self.x >= T::zero() && self.x <= T::one() &&
        self.y >= T::zero() && self.y <= T::one() &&
        self.luma >= T::zero() && self.luma <= T::one()
    }

    fn clamp(&self) -> Yxy<Wp, T> {
        let mut c = *self;
        c.clamp_self();
        c
    }

    fn clamp_self(&mut self) {
        self.x = clamp(self.x, T::zero(), T::one());
        self.y = clamp(self.y, T::zero(), T::one());
        self.luma = clamp(self.luma, T::zero(), T::one());
    }
}

impl<Wp, T> Mix for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
{
    type Scalar = T;

    fn mix(&self, other: &Yxy<Wp, T>, factor: T) -> Yxy<Wp, T> {
        let factor = clamp(factor, T::zero(), T::one());

        Yxy {
            x: self.x + factor * (other.x - self.x),
            y: self.y + factor * (other.y - self.y),
            luma: self.luma + factor * (other.luma - self.luma),
            white_point: PhantomData,
        }
    }
}

impl<Wp, T> Shade for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
{
    type Scalar = T;

    fn lighten(&self, amount: T) -> Yxy<Wp, T> {
        Yxy {
            x: self.x,
            y: self.y,
            luma: self.luma + amount,
            white_point: PhantomData,
        }
    }
}

impl<Wp, T> ComponentWise for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
{
    type Scalar = T;

    fn component_wise<F: FnMut(T, T) -> T>(&self, other: &Yxy<Wp, T>, mut f: F) -> Yxy<Wp, T> {
        Yxy {
            x: f(self.x, other.x),
            y: f(self.y, other.y),
            luma: f(self.luma, other.luma),
            white_point: PhantomData,
        }
    }

    fn component_wise_self<F: FnMut(T) -> T>(&self, mut f: F) -> Yxy<Wp, T> {
        Yxy {
            x: f(self.x),
            y: f(self.y),
            luma: f(self.luma),
            white_point: PhantomData,
        }
    }
}

impl<Wp, T> Default for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
{
    fn default() -> Yxy<Wp, T> {
        // The default for x and y are the white point x and y ( from the default D65).
        // Since Y (luma) is 0.0, this makes the default color black just like for
        // other colors. The reason for not using 0 for x and y is that this
        // outside the usual color gamut and might cause scaling issues.
        Yxy {
            luma: T::zero(),
            ..Wp::get_xyz().into_yxy()
        }
    }
}

impl<Wp, T> Add<Yxy<Wp, T>> for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
{
    type Output = Yxy<Wp, T>;

    fn add(self, other: Yxy<Wp, T>) -> Yxy<Wp, T> {
        Yxy {
            x: self.x + other.x,
            y: self.y + other.y,
            luma: self.luma + other.luma,
            white_point: PhantomData,
        }
    }
}

impl<Wp, T> Add<T> for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
{
    type Output = Yxy<Wp, T>;

    fn add(self, c: T) -> Yxy<Wp, T> {
        Yxy {
            x: self.x + c,
            y: self.y + c,
            luma: self.luma + c,
            white_point: PhantomData,
        }
    }
}

impl<Wp, T> Sub<Yxy<Wp, T>> for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
{
    type Output = Yxy<Wp, T>;

    fn sub(self, other: Yxy<Wp, T>) -> Yxy<Wp, T> {
        Yxy {
            x: self.x - other.x,
            y: self.y - other.y,
            luma: self.luma - other.luma,
            white_point: PhantomData,
        }
    }
}

impl<Wp, T> Sub<T> for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
{
    type Output = Yxy<Wp, T>;

    fn sub(self, c: T) -> Yxy<Wp, T> {
        Yxy {
            x: self.x - c,
            y: self.y - c,
            luma: self.luma - c,
            white_point: PhantomData,
        }
    }
}

impl<Wp, T> Mul<Yxy<Wp, T>> for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
{
    type Output = Yxy<Wp, T>;

    fn mul(self, other: Yxy<Wp, T>) -> Yxy<Wp, T> {
        Yxy {
            x: self.x * other.x,
            y: self.y * other.y,
            luma: self.luma * other.luma,
            white_point: PhantomData,
        }
    }
}

impl<Wp, T> Mul<T> for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
{
    type Output = Yxy<Wp, T>;

    fn mul(self, c: T) -> Yxy<Wp, T> {
        Yxy {
            x: self.x * c,
            y: self.y * c,
            luma: self.luma * c,
            white_point: PhantomData,
        }
    }
}

impl<Wp, T> Div<Yxy<Wp, T>> for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
{
    type Output = Yxy<Wp, T>;

    fn div(self, other: Yxy<Wp, T>) -> Yxy<Wp, T> {
        Yxy {
            x: self.x / other.x,
            y: self.y / other.y,
            luma: self.luma / other.luma,
            white_point: PhantomData,
        }
    }
}

impl<Wp, T> Div<T> for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
{
    type Output = Yxy<Wp, T>;

    fn div(self, c: T) -> Yxy<Wp, T> {
        Yxy {
            x: self.x / c,
            y: self.y / c,
            luma: self.luma / c,
            white_point: PhantomData,
        }
    }
}

impl<Wp, T, P> AsRef<P> for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
    P: RawPixel<T> + ?Sized,
{
    fn as_ref(&self) -> &P {
        self.as_raw()
    }
}

impl<Wp, T, P> AsMut<P> for Yxy<Wp, T>
where
    T: Component + Float,
    Wp: WhitePoint,
    P: RawPixel<T> + ?Sized,
{
    fn as_mut(&mut self) -> &mut P {
        self.as_raw_mut()
    }
}

#[cfg(test)]
mod test {
    use super::Yxy;
    use white_point::D65;
    use LinLuma;
    use LinSrgb;

    #[test]
    fn luma() {
        let a = Yxy::from(LinLuma::new(0.5));
        let b = Yxy::new(0.312727, 0.329023, 0.5);
        assert_relative_eq!(a, b, epsilon = 0.000001);
    }

    #[test]
    fn red() {
        let a = Yxy::from(LinSrgb::new(1.0, 0.0, 0.0));
        let b = Yxy::new(0.64, 0.33, 0.212673);
        assert_relative_eq!(a, b, epsilon = 0.000001);
    }

    #[test]
    fn green() {
        let a = Yxy::from(LinSrgb::new(0.0, 1.0, 0.0));
        let b = Yxy::new(0.3, 0.6, 0.715152);
        assert_relative_eq!(a, b, epsilon = 0.000001);
    }

    #[test]
    fn blue() {
        let a = Yxy::from(LinSrgb::new(0.0, 0.0, 1.0));
        let b = Yxy::new(0.15, 0.06, 0.072175);
        assert_relative_eq!(a, b, epsilon = 0.000001);
    }

    #[test]
    fn ranges() {
        assert_ranges!{
            Yxy<D65, f64>;
            limited {
                x: 0.0 => 1.0,
                y: 0.0 => 1.0,
                luma: 0.0 => 1.0
            }
            limited_min {}
            unlimited {}
        }
    }

    raw_pixel_conversion_tests!(Yxy<D65>: x, y, luma);
    raw_pixel_conversion_fail_tests!(Yxy<D65>: x, y, luma);

    #[cfg(feature = "serde")]
    #[test]
    fn serialize() {
        let serialized = ::serde_json::to_string(&Yxy::new(0.3, 0.8, 0.1)).unwrap();

        assert_eq!(serialized, r#"{"x":0.3,"y":0.8,"luma":0.1}"#);
    }

    #[cfg(feature = "serde")]
    #[test]
    fn deserialize() {
        let deserialized: Yxy = ::serde_json::from_str(r#"{"x":0.3,"y":0.8,"luma":0.1}"#).unwrap();

        assert_eq!(deserialized, Yxy::new(0.3, 0.8, 0.1));
    }
}