// Copyright 2013 The Servo Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use length::Length;
use num::Zero;
use point::Point2D;
use size::Size2D;

use num_lib::NumCast;
use std::cmp::PartialOrd;
use std::fmt::{self, Formatter};
use std::ops::{Add, Sub, Mul, Div};

#[derive(Clone, Copy, RustcDecodable, RustcEncodable, PartialEq)]
#[cfg_attr(feature = "plugins", derive(HeapSizeOf, Deserialize, Serialize))]
pub struct Rect<T> {
    pub origin: Point2D<T>,
    pub size: Size2D<T>,
}

impl<T: fmt::Debug> fmt::Debug for Rect<T> {
   fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "Rect({:?} at {:?})", self.size, self.origin)
    }
}

impl<T: fmt::Display> fmt::Display for Rect<T> {
    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        write!(formatter, "Rect({} at {})", self.size.to_string(), self.origin.to_string())
    }
}

impl<T: Clone> Rect<T> {
    pub fn new(origin: Point2D<T>, size: Size2D<T>) -> Rect<T> {
        Rect {
            origin: origin,
            size: size
        }
    }
}

impl<T: Copy + Clone + PartialOrd + Add<T, Output=T> + Sub<T, Output=T> + Zero> Rect<T> {
    #[inline]
    pub fn intersects(&self, other: &Rect<T>) -> bool {
        self.origin.x < other.origin.x + other.size.width &&
       other.origin.x <  self.origin.x + self.size.width &&
        self.origin.y < other.origin.y + other.size.height &&
       other.origin.y <  self.origin.y + self.size.height
    }

    #[inline]
    pub fn max_x(&self) -> T {
        self.origin.x + self.size.width
    }

    #[inline]
    pub fn min_x(&self) -> T {
        self.origin.x.clone()
    }

    #[inline]
    pub fn max_y(&self) -> T {
        self.origin.y + self.size.height
    }

    #[inline]
    pub fn min_y(&self) -> T {
        self.origin.y.clone()
    }

    #[inline]
    pub fn intersection(&self, other: &Rect<T>) -> Option<Rect<T>> {
        if !self.intersects(other) {
            return None;
        }

        let upper_left = Point2D::new(max(self.min_x(), other.min_x()),
                                      max(self.min_y(), other.min_y()));
        let lower_right = Point2D::new(min(self.max_x(), other.max_x()),
                                       min(self.max_y(), other.max_y()));

        Some(Rect::new(upper_left.clone(), Size2D::new(lower_right.x - upper_left.x,
                                                       lower_right.y - upper_left.y)))
    }

    #[inline]
    pub fn union(&self, other: &Rect<T>) -> Rect<T> {
        if self.size == Zero::zero() {
            return *other
        }
        if other.size == Zero::zero() {
            return *self
        }

        let upper_left = Point2D::new(min(self.min_x(), other.min_x()),
                                      min(self.min_y(), other.min_y()));

        let lower_right = Point2D::new(max(self.max_x(), other.max_x()),
                                       max(self.max_y(), other.max_y()));

        Rect {
            origin: upper_left.clone(),
            size: Size2D::new(lower_right.x - upper_left.x, lower_right.y - upper_left.y)
        }
    }

    #[inline]
    pub fn translate(&self, other: &Point2D<T>) -> Rect<T> {
        Rect {
            origin: Point2D::new(self.origin.x + other.x, self.origin.y + other.y),
            size: self.size.clone()
        }
    }

    #[inline]
    pub fn contains(&self, other: &Point2D<T>) -> bool {
        self.origin.x <= other.x && other.x < self.origin.x + self.size.width &&
        self.origin.y <= other.y && other.y < self.origin.y + self.size.height
    }

    #[inline]
    pub fn inflate(&self, width: T, height: T) -> Rect<T> {
        Rect {
            origin: Point2D::new(self.origin.x - width, self.origin.y - height),
            size: Size2D::new(self.size.width + width + width, self.size.height + height + height),
        }
    }

    #[inline]
    pub fn top_right(&self) -> Point2D<T> {
        Point2D::new(self.max_x(), self.origin.y.clone())
    }

    #[inline]
    pub fn bottom_left(&self) -> Point2D<T> {
        Point2D::new(self.origin.x.clone(), self.max_y())
    }

    #[inline]
    pub fn bottom_right(&self) -> Point2D<T> {
        Point2D::new(self.max_x(), self.max_y())
    }

    #[inline]
    pub fn translate_by_size(&self, size: &Size2D<T>) -> Rect<T> {
        Rect::new(Point2D::new(self.origin.x + size.width, self.origin.y + size.height),
                  self.size.clone())
    }
}

impl<T> Rect<T> {
    #[inline]
    pub fn scale<Scale: Copy>(&self, x: Scale, y: Scale) -> Rect<T>
        where T: Copy + Clone + Mul<Scale, Output=T> {
        Rect {
            origin: Point2D { x: self.origin.x * x, y: self.origin.y * y},
            size: Size2D { width: self.size.width * x, height: self.size.height * y}
        }
    }
}

impl<T: PartialEq + Zero> Rect<T> {
    pub fn zero() -> Rect<T> {
        Rect {
            origin: Point2D::zero(),
            size: Size2D::zero(),
        }
    }

    pub fn is_empty(&self) -> bool {
        self.size.width == Zero::zero() || self.size.height == Zero::zero()
    }
}


pub fn min<T:Clone + PartialOrd>(x: T, y: T) -> T {
    if x <= y { x } else { y }
}

pub fn max<T:Clone + PartialOrd>(x: T, y: T) -> T {
    if x >= y { x } else { y }
}

impl<Scale: Copy, T0: Mul<Scale, Output=T1>, T1: Clone> Mul<Scale> for Rect<T0> {
    type Output = Rect<T1>;
    #[inline]
    fn mul(self, scale: Scale) -> Rect<T1> {
        Rect::new(self.origin * scale, self.size * scale)
    }
}

impl<Scale: Copy, T0: Div<Scale, Output=T1>, T1: Clone> Div<Scale> for Rect<T0> {
    type Output = Rect<T1>;
    #[inline]
    fn div(self, scale: Scale) -> Rect<T1> {
        Rect::new(self.origin / scale, self.size / scale)
    }
}

// Convenient aliases for Rect with typed units
pub type TypedRect<Unit, T> = Rect<Length<Unit, T>>;

impl<Unit, T: Clone> Rect<Length<Unit, T>> {
    /// Drop the units, preserving only the numeric value.
    pub fn to_untyped(&self) -> Rect<T> {
        Rect::new(self.origin.to_untyped(), self.size.to_untyped())
    }

    /// Tag a unitless value with units.
    pub fn from_untyped(r: &Rect<T>) -> TypedRect<Unit, T> {
        Rect::new(Point2D::from_untyped(&r.origin), Size2D::from_untyped(&r.size))
    }
}

impl<Unit, T0: NumCast + Clone> Rect<Length<Unit, T0>> {
    /// Cast from one numeric representation to another, preserving the units.
    pub fn cast<T1: NumCast + Clone>(&self) -> Option<Rect<Length<Unit, T1>>> {
        match (self.origin.cast(), self.size.cast()) {
            (Some(origin), Some(size)) => Some(Rect::new(origin, size)),
            _ => None
        }
    }
}

// Convenience functions for common casts
impl<Unit, T: NumCast + Clone> Rect<Length<Unit, T>> {
    pub fn as_f32(&self) -> Rect<Length<Unit, f32>> {
        self.cast().unwrap()
    }

    pub fn as_uint(&self) -> Rect<Length<Unit, usize>> {
        self.cast().unwrap()
    }
}

#[test]
fn test_min_max() {
    assert!(min(0u32, 1u32) == 0u32);
    assert!(min(-1.0f32, 0.0f32) == -1.0f32);

    assert!(max(0u32, 1u32) == 1u32);
    assert!(max(-1.0f32, 0.0f32) == 0.0f32);
}

#[test]
fn test_translate() {
    let p = Rect::new(Point2D::new(0u32, 0u32), Size2D::new(50u32, 40u32));
    let pp = p.translate(&Point2D::new(10,15));

    assert!(pp.size.width == 50);
    assert!(pp.size.height == 40);
    assert!(pp.origin.x == 10);
    assert!(pp.origin.y == 15);


    let r = Rect::new(Point2D::new(-10, -5), Size2D::new(50, 40));
    let rr = r.translate(&Point2D::new(0,-10));

    assert!(rr.size.width == 50);
    assert!(rr.size.height == 40);
    assert!(rr.origin.x == -10);
    assert!(rr.origin.y == -15);
}

#[test]
fn test_union() {
    let p = Rect::new(Point2D::new(0, 0), Size2D::new(50, 40));
    let q = Rect::new(Point2D::new(20,20), Size2D::new(5, 5));
    let r = Rect::new(Point2D::new(-15, -30), Size2D::new(200, 15));
    let s = Rect::new(Point2D::new(20, -15), Size2D::new(250, 200));

    let pq = p.union(&q);
    assert!(pq.origin == Point2D::new(0, 0));
    assert!(pq.size == Size2D::new(50, 40));

    let pr = p.union(&r);
    assert!(pr.origin == Point2D::new(-15, -30));
    assert!(pr.size == Size2D::new(200, 70));

    let ps = p.union(&s);
    assert!(ps.origin == Point2D::new(0, -15));
    assert!(ps.size == Size2D::new(270, 200));

}

#[test]
fn test_intersection() {
    let p = Rect::new(Point2D::new(0, 0), Size2D::new(10, 20));
    let q = Rect::new(Point2D::new(5, 15), Size2D::new(10, 10));
    let r = Rect::new(Point2D::new(-5, -5), Size2D::new(8, 8));

    let pq = p.intersection(&q);
    assert!(pq.is_some());
    let pq = pq.unwrap();
    assert!(pq.origin == Point2D::new(5, 15));
    assert!(pq.size == Size2D::new(5, 5));

    let pr = p.intersection(&r);
    assert!(pr.is_some());
    let pr = pr.unwrap();
    assert!(pr.origin == Point2D::new(0, 0));
    assert!(pr.size == Size2D::new(3, 3));

    let qr = q.intersection(&r);
    assert!(qr.is_none());
}

#[test]
fn test_contains() {
    let r = Rect::new(Point2D::new(-20, 15), Size2D::new(100, 200));

    assert!(r.contains(&Point2D::new(0, 50)));
    assert!(r.contains(&Point2D::new(-10, 200)));

    // The `contains` method is inclusive of the top/left edges, but not the
    // bottom/right edges.
    assert!(r.contains(&Point2D::new(-20, 15)));
    assert!(!r.contains(&Point2D::new(80, 15)));
    assert!(!r.contains(&Point2D::new(80, 215)));
    assert!(!r.contains(&Point2D::new(-20, 215)));

    // Points beyond the top-left corner.
    assert!(!r.contains(&Point2D::new(-25, 15)));
    assert!(!r.contains(&Point2D::new(-15, 10)));

    // Points beyond the top-right corner.
    assert!(!r.contains(&Point2D::new(85, 20)));
    assert!(!r.contains(&Point2D::new(75, 10)));

    // Points beyond the bottom-right corner.
    assert!(!r.contains(&Point2D::new(85, 210)));
    assert!(!r.contains(&Point2D::new(75, 220)));

    // Points beyond the bottom-left corner.
    assert!(!r.contains(&Point2D::new(-25, 210)));
    assert!(!r.contains(&Point2D::new(-15, 220)));
}

#[test]
fn test_scale() {
    let p = Rect::new(Point2D::new(0u32, 0u32), Size2D::new(50u32, 40u32));
    let pp = p.scale(10, 15);

    assert!(pp.size.width == 500);
    assert!(pp.size.height == 600);
    assert!(pp.origin.x == 0);
    assert!(pp.origin.y == 0);

    let r = Rect::new(Point2D::new(-10, -5), Size2D::new(50, 40));
    let rr = r.scale(1, 20);

    assert!(rr.size.width == 50);
    assert!(rr.size.height == 800);
    assert!(rr.origin.x == -10);
    assert!(rr.origin.y == -100);
}

#[test]
fn test_inflate() {
    let p = Rect::new(Point2D::new(0, 0), Size2D::new(10, 10));
    let pp = p.inflate(10, 20);

    assert!(pp.size.width == 30);
    assert!(pp.size.height == 50);
    assert!(pp.origin.x == -10);
    assert!(pp.origin.y == -20);

    let r = Rect::new(Point2D::new(0, 0), Size2D::new(10, 20));
    let rr = r.inflate(-2, -5);

    assert!(rr.size.width == 6);
    assert!(rr.size.height == 10);
    assert!(rr.origin.x == 2);
    assert!(rr.origin.y == 5);
}

#[test]
fn test_min_max_x_y() {
    let p = Rect::new(Point2D::new(0u32, 0u32), Size2D::new(50u32, 40u32));
    assert!(p.max_y() == 40);
    assert!(p.min_y() == 0);
    assert!(p.max_x() == 50);
    assert!(p.min_x() == 0);

    let r = Rect::new(Point2D::new(-10, -5), Size2D::new(50, 40));
    assert!(r.max_y() == 35);
    assert!(r.min_y() == -5);
    assert!(r.max_x() == 40);
    assert!(r.min_x() == -10);
}

#[test]
fn test_is_empty() {
    assert!(Rect::new(Point2D::new(0u32, 0u32), Size2D::new(0u32, 0u32)).is_empty());
    assert!(Rect::new(Point2D::new(0u32, 0u32), Size2D::new(10u32, 0u32)).is_empty());
    assert!(Rect::new(Point2D::new(0u32, 0u32), Size2D::new(0u32, 10u32)).is_empty());
    assert!(!Rect::new(Point2D::new(0u32, 0u32), Size2D::new(1u32, 1u32)).is_empty());
    assert!(Rect::new(Point2D::new(10u32, 10u32), Size2D::new(0u32, 0u32)).is_empty());
    assert!(Rect::new(Point2D::new(10u32, 10u32), Size2D::new(10u32, 0u32)).is_empty());
    assert!(Rect::new(Point2D::new(10u32, 10u32), Size2D::new(0u32, 10u32)).is_empty());
    assert!(!Rect::new(Point2D::new(10u32, 10u32), Size2D::new(1u32, 1u32)).is_empty());
}