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//! Math types and helpers.
//!
//! Consists of re-exported `glam` types with some additions.

pub use glam::*;

#[derive(Clone, Copy, Debug, Default, PartialEq)]
pub struct Rect {
    pub x: f32,
    pub y: f32,
    pub w: f32,
    pub h: f32,
}

impl Rect {
    pub fn new(x: f32, y: f32, w: f32, h: f32) -> Rect {
        Rect { x, y, w, h }
    }

    pub fn point(&self) -> Vec2 {
        vec2(self.x, self.y)
    }

    pub fn size(&self) -> Vec2 {
        vec2(self.w, self.h)
    }

    /// Returns the left edge of the `Rect`
    pub fn left(&self) -> f32 {
        self.x
    }

    /// Returns the right edge of the `Rect`
    pub fn right(&self) -> f32 {
        self.x + self.w
    }

    /// Returns the top edge of the `Rect`
    pub fn top(&self) -> f32 {
        self.y
    }

    /// Returns the bottom edge of the `Rect`
    pub fn bottom(&self) -> f32 {
        self.y + self.h
    }

    /// Moves the `Rect`'s origin to (x, y)
    pub fn move_to(&mut self, destination: Vec2) {
        self.x = destination.x;
        self.y = destination.y;
    }

    /// Scales the `Rect` by a factor of (sx, sy),
    /// growing towards the bottom-left
    pub fn scale(&mut self, sx: f32, sy: f32) {
        self.w *= sx;
        self.h *= sy;
    }

    /// Checks whether the `Rect` contains a `Point`
    pub fn contains(&self, point: Vec2) -> bool {
        point.x >= self.left()
            && point.x < self.right()
            && point.y < self.bottom()
            && point.y >= self.top()
    }

    /// Checks whether the `Rect` overlaps another `Rect`
    pub fn overlaps(&self, other: &Rect) -> bool {
        self.left() <= other.right()
            && self.right() >= other.left()
            && self.top() <= other.bottom()
            && self.bottom() >= other.top()
    }

    /// Returns a new `Rect` that includes all points of these two `Rect`s.
    pub fn combine_with(self, other: Rect) -> Rect {
        let x = f32::min(self.x, other.x);
        let y = f32::min(self.y, other.y);
        let w = f32::max(self.right(), other.right()) - x;
        let h = f32::max(self.bottom(), other.bottom()) - y;
        Rect { x, y, w, h }
    }

    /// Returns an intersection rect there is any intersection
    pub fn intersect(&self, other: Rect) -> Option<Rect> {
        let left = self.x.max(other.x);
        let top = self.y.max(other.y);
        let right = self.right().min(other.right());
        let bottom = self.bottom().min(other.bottom());

        if right < left || bottom < top {
            return None;
        }

        Some(Rect {
            x: left,
            y: top,
            w: right - left,
            h: bottom - top,
        })
    }

    /// Translate rect origin be `offset` vector
    pub fn offset(self, offset: Vec2) -> Rect {
        Rect::new(self.x + offset.x, self.y + offset.y, self.w, self.h)
    }
}

#[derive(Clone, Copy, Debug, Default, PartialEq)]
pub struct RectOffset {
    pub left: f32,
    pub right: f32,
    pub bottom: f32,
    pub top: f32,
}

impl RectOffset {
    pub fn new(left: f32, right: f32, top: f32, bottom: f32) -> RectOffset {
        RectOffset {
            left,
            right,
            top,
            bottom,
        }
    }
}

/// Converts 2d polar coordinates to 2d cartesian coordinates.
pub fn polar_to_cartesian(rho: f32, theta: f32) -> Vec2 {
    vec2(rho * theta.cos(), rho * theta.sin())
}

/// Converts 2d cartesian coordinates to 2d polar coordinates.
pub fn cartesian_to_polar(cartesian: Vec2) -> Vec2 {
    vec2(
        (cartesian.x.powi(2) + cartesian.y.powi(2)).sqrt(),
        cartesian.y.atan2(cartesian.x),
    )
}

/// Returns value, bounded in range [min, max].
pub fn clamp<T: PartialOrd>(value: T, min: T, max: T) -> T {
    if value < min {
        min
    } else if value > max {
        max
    } else {
        value
    }
}