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// Copyright (c) 2018-2020 Thomas Kramer.
//

//! Commonly used type definitions and constants.

/// Precision for distance related decisions.
pub const PREC_DISTANCE: DistanceType = 1e-5;

/// Default floating point type.
pub type FloatType = f64;

/// Default type for euclidean distances.
pub type DistanceType = FloatType;

/// Angle expressed as a multiple of 90 degrees.
#[derive(Copy, Clone, Hash, PartialEq, Eq, Debug)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub enum Angle {
/// 0 Degrees.
R0,
/// 90 Degrees.
R90,
/// 180 Degrees.
R180,
/// 270 Degrees.
R270,
}

impl Angle {
/// Describe the angle as a integer multiple of 90 degrees.
pub fn as_int(&self) -> u32 {
match self {
Angle::R0 => 0,
Angle::R90 => 1,
Angle::R180 => 2,
Angle::R270 => 3,
}
}

/// Convert an integer to an angle.
/// The integer specifies the number of 90 degree rotations.
pub fn from_u32(a: u32) -> Self {
match a % 4 {
0 => Angle::R0,
1 => Angle::R90,
2 => Angle::R180,
3 => Angle::R270,
_ => unreachable!(),
}
}
}

type Output = Self;

fn add(self, rhs: Self) -> Self::Output {
Self::from_u32(self.as_int() + rhs.as_int())
}
}

impl Sub for Angle {
type Output = Self;

fn sub(self, rhs: Self) -> Self::Output {
Self::from_u32(self.as_int() + 4 - rhs.as_int())
}
}

impl Neg for Angle {
type Output = Self;

fn neg(self) -> Self::Output {
Self::from_u32(4 - self.as_int())
}
}

impl Default for Angle {
fn default() -> Self {
Angle::R0
}
}

/// Location relative to a directed line or edge.
/// Something can be on the left of the line, right of the line or on top of the line (center).
#[derive(Clone, Copy, Hash, PartialEq, Debug)]
pub enum Side {
/// Location on the left side.
Left,
/// Neither on the left nor right, but on top.
Center,
/// Location on the right side.
Right,
}

impl Side {
/// Test if this is the left side.
pub fn is_left(&self) -> bool {
*self == Side::Left
}
/// Test if this is the right side.
pub fn is_right(&self) -> bool {
*self == Side::Right
}
/// Test if this is `Center`.
pub fn is_center(&self) -> bool {
*self == Side::Center
}

/// Get the other side.
pub fn other(&self) -> Self {
match self {
Side::Left => Side::Right,
Side::Center => Side::Center,
Side::Right => Side::Left,
}
}
}

/// Relative orientation of two geometrical objects such as vectors.
#[derive(Clone, Copy, Hash, PartialEq, Debug)]
pub enum Orientation {
/// Clock-wise orientation.
ClockWise,
/// Counter-clock-wise orientation.
CounterClockWise,
/// Neither clock-wise nor counter-clock-wise.
Straight,
}

impl Orientation {
/// Test if the orientation is equal to `ClockWise`.
pub fn is_clock_wise(self) -> bool {
self == Self::ClockWise
}
/// Test if the orientation is equal to `CounterClockWise`.
pub fn is_counter_clock_wise(self) -> bool {
self == Self::CounterClockWise
}
/// Test if the orientation is equal to `Straight`.
pub fn is_straight(self) -> bool {
self == Self::Straight
}
}

/// This is a result type for containment checks.
/// * `No` Not inside.
/// * `OnBounds` Lies on the boundaries.
/// * `WithinBounds` Fully inside.
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
pub enum ContainsResult {
/// Does not contain the point.
No,
/// Contains the point but on the borders/end-points.
OnBounds,
/// Fully contains the point.
WithinBounds,
}

impl ContainsResult {
/// Tells if the point is contained but does not lie on the bounds.
pub fn is_within_bounds(&self) -> bool {
matches!(self, ContainsResult::WithinBounds)
}

/// Tells if the point is contained or lies on the bounds.
pub fn inclusive_bounds(&self) -> bool {
matches!(
self,
ContainsResult::WithinBounds | ContainsResult::OnBounds
)
}

/// Check if the point neither is on the bounds nor within the bounds.
pub fn on_bounds(&self) -> bool {
matches!(self, ContainsResult::OnBounds)
}

/// Check if the point lies on the bounds.
pub fn is_no(&self) -> bool {
matches!(self, ContainsResult::No)
}

/// Returns the stronger result of the both.
/// Ordering from weak to strong is `No`, `OnBounds`, `WithinBounds`
pub fn max(self, other: Self) -> Self {
match (self, other) {
(ContainsResult::WithinBounds, _) => ContainsResult::WithinBounds,
(_, ContainsResult::WithinBounds) => ContainsResult::WithinBounds,
(ContainsResult::OnBounds, _) => ContainsResult::OnBounds,
(_, ContainsResult::OnBounds) => ContainsResult::OnBounds,
(ContainsResult::No, _) => ContainsResult::No,
}
}

/// Returns the weaker result of the both.
/// Ordering from weak to strong is `No`, `OnBounds`, `WithinBounds`
pub fn min(self, other: Self) -> Self {
match (self, other) {
(ContainsResult::No, _) => ContainsResult::No,
(_, ContainsResult::No) => ContainsResult::No,
(ContainsResult::OnBounds, _) => ContainsResult::OnBounds,
(_, ContainsResult::OnBounds) => ContainsResult::OnBounds,
(ContainsResult::WithinBounds, _) => ContainsResult::WithinBounds,
}
}
}