use super::Vec2;
use nalgebra::{RealField, Scalar};
use serde::{Deserialize, Serialize};
use std::ops::{Add, AddAssign};

/// Represents a Rectangle with the value type T.
#[derive(Copy, Clone, Debug, Default, Serialize, Deserialize)]
pub struct Rect<T: Scalar + Copy> {
    /// The x coordinate, or leftmost coordinate of the Rect.
    pub x: T,
    /// The y coordinate, or rightmost coordinate of the Rect.
    pub y: T,
    /// The width of the Rect.
    pub w: T,
    /// The height of the Rect.
    pub h: T,
}

// This is sad, but also sadly necessary :/
impl<T: Into<f32> + Scalar + Copy> Into<raylib::ffi::Rectangle> for Rect<T> {
    fn into(self) -> raylib::ffi::Rectangle {
        raylib::ffi::Rectangle {
            x: self.x.into(),
            y: self.y.into(),
            width: self.w.into(),
            height: self.h.into(),
        }
    }
}
impl<T: From<f32> + Scalar + Copy> From<raylib::ffi::Rectangle> for Rect<T> {
    fn from(r: raylib::ffi::Rectangle) -> Self {
        Self {
            x: T::from(r.x),
            y: T::from(r.y),
            w: T::from(r.width),
            h: T::from(r.height),
        }
    }
}
impl<T: Into<f32> + Scalar + Copy> Into<raylib::math::Rectangle> for Rect<T> {
    fn into(self) -> raylib::math::Rectangle {
        raylib::math::Rectangle {
            x: self.x.into(),
            y: self.y.into(),
            width: self.w.into(),
            height: self.h.into(),
        }
    }
}
impl<T: From<f32> + Scalar + Copy> From<raylib::math::Rectangle> for Rect<T> {
    fn from(r: raylib::math::Rectangle) -> Self {
        Self {
            x: T::from(r.x),
            y: T::from(r.y),
            w: T::from(r.width),
            h: T::from(r.height),
        }
    }
}

impl<T: Scalar + Copy> Rect<T> {
    pub fn new(x: T, y: T, w: T, h: T) -> Self {
        Self { x, y, w, h }
    }

    /// Create a Rectangle from a slice. Indices are [x, y, w, h].
    pub fn from_slice(slice: [T; 4]) -> Rect<T>
    where
        T: Copy,
    {
        Rect {
            x: slice[0],
            y: slice[1],
            w: slice[2],
            h: slice[3],
        }
    }

    /// Move by the Vec provided.
    pub fn translate(&mut self, by: Vec2<T>)
    where
        T: AddAssign,
    {
        self.x += by.x;
        self.y += by.y;
    }

    /// Set the posiotien of the rectangle to the given one without changing its
    /// size
    pub fn set_pos(&mut self, pos: Vec2<T>) {
        self.x = pos.x;
        self.y = pos.y;
    }

    /// Test if two rectangles intersect.
    pub fn intersect<'a>(this: &'a Rect<T>, other: &'a Rect<T>) -> bool
    where
        T: Add<Output = T> + PartialOrd + Copy,
    {
        !(this.x > other.x + other.w
            || this.x + this.w < other.x
            || this.y > other.y + other.h
            || this.y + this.h < other.y)
    }

    /// Check if the point is inside this Rect and return true if so.
    pub fn contains(&self, point: Vec2<T>) -> bool
    where
        T: PartialOrd + Add<Output = T>,
    {
        point.x >= self.x
            && point.x <= self.x + self.w
            && point.y >= self.y
            && point.y <= self.y + self.h
    }

    /// Function to calculate the bounding rectangle that is between two vectors. The order of the
    /// vectors is irrelevent for this. As long as they are diagonally opposite of each other, this
    /// function will work.
    pub fn bounding_rect(pos1: Vec2<T>, pos2: Vec2<T>) -> Self
    where
        T: RealField,
    {
        let min_x = pos1.x.min(pos2.x);
        let min_y = pos1.y.min(pos2.y);
        let max_x = pos1.x.max(pos2.x);
        let max_y = pos1.y.max(pos2.y);

        Self {
            x: min_x,
            y: min_y,
            w: max_x - min_x,
            h: max_y - min_y,
        }
    }

    /// Get the shortest way that must be applied to this Rect to clear out of
    /// another Rect of the same type so that they would not intersect any more.
    pub fn shortest_way_out(&self, of: &Rect<T>) -> Vec2<T>
    where
        T: RealField,
    {
        // Check upwards
        let mut move_y = of.y - self.y - self.h;
        // Check downwards
        let move_down = of.y + of.h - self.y;
        if move_down < -move_y {
            move_y = move_down;
        }

        // Check left
        let mut move_x = of.x - self.x - self.w;
        // Check right
        let move_right = of.x + of.w - self.x;
        if move_right < -move_x {
            move_x = move_right;
        }

        if move_x.abs() < move_y.abs() {
            Vec2::new(move_x, T::zero())
        } else {
            Vec2::new(T::zero(), move_y)
        }
    }
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn test_intersect() {
        let a = Rect::from_slice([0, 0, 4, 4]);
        let b = Rect::from_slice([-1, -1, 1, 1]);

        assert!(Rect::intersect(&a, &b));
    }
}