use crate::{Frame, Pixel, Ref, View, P2};
use std::ops::{Add, AddAssign, Index, IndexMut, Sub};

#[cfg(feature = "parallel")]
pub use rayon::join;
#[cfg(not(feature = "parallel"))]
pub fn join<A, B, RA, RB>(oper_a: A, oper_b: B) -> (RA, RB)
where
    A: FnOnce() -> RA + Send,
    B: FnOnce() -> RB + Send,
    RA: Send,
    RB: Send,
{
    (oper_a(), oper_b())
}

impl Frame {
    pub fn export(&self, view: View) -> Vec<Pixel> {
        let mut o = vec![];
        for y in view.a.y..view.b.y {
            for x in view.a.x..view.b.x {
                o.push(self[P2 { x, y }])
            }
        }
        o
    }
    pub fn import(&mut self, view: View, mut source: &[Pixel]) {
        for y in view.a.y..view.b.y {
            for x in view.a.x..view.b.x {
                self[P2 { x, y }] = source[0];
                source = &source[1..];
            }
        }
        assert_eq!(source.len(), 0)
    }
    pub fn new(size: P2) -> Self {
        Self {
            pixels: vec![Pixel::default(); size.area()],
            size,
        }
    }
}
impl Ref {
    #[inline]
    pub fn apply<F: Fn(&mut Self)>(mut self, f: F) -> Self {
        f(&mut self);
        self
    }
}
impl Pixel {
    pub const BLACK: Pixel = Pixel { r: 0, g: 0, b: 0 };
    pub const RED: Pixel = Pixel { r: 255, g: 0, b: 0 };
    pub const GREEN: Pixel = Pixel { r: 0, g: 255, b: 0 };
    pub const BLUE: Pixel = Pixel { r: 0, g: 0, b: 255 };
}
impl AddAssign for P2 {
    fn add_assign(&mut self, rhs: Self) {
        self.x += rhs.x;
        self.y += rhs.y;
    }
}
impl Add for Pixel {
    type Output = Pixel;
    #[inline]
    fn add(self, rhs: Self) -> Self::Output {
        Self {
            r: self.r + rhs.r,
            g: self.g + rhs.g,
            b: self.b + rhs.b,
        }
    }
}
impl Sub for Pixel {
    type Output = Pixel;
    #[inline]
    fn sub(self, rhs: Self) -> Self::Output {
        Self {
            r: self.r - rhs.r,
            g: self.g - rhs.g,
            b: self.b - rhs.b,
        }
    }
}
impl P2 {
    pub const ZERO: P2 = P2 { x: 0, y: 0 };
    pub const X: P2 = P2 { x: 1, y: 0 };
    pub const Y: P2 = P2 { x: 0, y: 1 };

    #[inline]
    pub fn area(&self) -> usize {
        (self.x * self.y) as usize
    }
}
impl View {
    #[inline]
    pub fn all(b: P2) -> Self {
        Self {
            a: P2::default(),
            b,
        }
    }
    #[inline]
    pub fn size(&self) -> P2 {
        self.b - self.a
    }
}
impl Add<P2> for View {
    type Output = View;
    #[inline]
    fn add(self, rhs: P2) -> Self::Output {
        View {
            a: self.a + rhs,
            b: self.b + rhs,
        }
    }
}
impl Add for P2 {
    type Output = P2;
    #[inline]
    fn add(self, rhs: Self) -> Self::Output {
        Self {
            x: self.x + rhs.x,
            y: self.y + rhs.y,
        }
    }
}
impl Sub for P2 {
    type Output = P2;
    #[inline]
    fn sub(self, rhs: Self) -> Self::Output {
        Self {
            x: self.x - rhs.x,
            y: self.y - rhs.y,
        }
    }
}

impl Index<P2> for Frame {
    type Output = Pixel;
    #[inline]
    fn index(&self, P2 { x, y }: P2) -> &Self::Output {
        &self
            .pixels
            .get(x as usize + (y as usize * self.size.x as usize))
            .unwrap_or(&Pixel { r: 0, g: 0, b: 0 })
    }
}
impl IndexMut<P2> for Frame {
    #[inline]
    fn index_mut(&mut self, P2 { x, y }: P2) -> &mut Self::Output {
        &mut self.pixels[x as usize + (y as usize * self.size.x as usize)]
    }
}

pub trait ToArray {
    type Output;
    fn to_array(self) -> [Self::Output; 2];
}
impl<A> ToArray for (A, A) {
    type Output = A;
    #[inline]
    fn to_array(self) -> [A; 2] {
        [self.0, self.1]
    }
}