/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

//! Generic types for CSS handling of specified and computed values of
//! [`position`](https://drafts.csswg.org/css-backgrounds-3/#position)

/// A generic type for representing a CSS [position](https://drafts.csswg.org/css-values/#position).
#[derive(
    Animate,
    Clone,
    ComputeSquaredDistance,
    Copy,
    Debug,
    MallocSizeOf,
    PartialEq,
    SpecifiedValueInfo,
    ToAnimatedValue,
    ToAnimatedZero,
    ToComputedValue,
    ToResolvedValue,
    ToShmem,
)]
#[repr(C)]
pub struct GenericPosition<H, V> {
    /// The horizontal component of position.
    pub horizontal: H,
    /// The vertical component of position.
    pub vertical: V,
}

pub use self::GenericPosition as Position;

impl<H, V> Position<H, V> {
    /// Returns a new position.
    pub fn new(horizontal: H, vertical: V) -> Self {
        Self {
            horizontal,
            vertical,
        }
    }
}

/// A generic type for representing an `Auto | <position>`.
/// This is used by <offset-anchor> for now.
/// https://drafts.fxtf.org/motion-1/#offset-anchor-property
#[derive(
    Animate,
    Clone,
    ComputeSquaredDistance,
    Copy,
    Debug,
    MallocSizeOf,
    Parse,
    PartialEq,
    SpecifiedValueInfo,
    ToAnimatedZero,
    ToComputedValue,
    ToCss,
    ToResolvedValue,
    ToShmem,
)]
#[repr(C, u8)]
pub enum GenericPositionOrAuto<Pos> {
    /// The <position> value.
    Position(Pos),
    /// The keyword `auto`.
    Auto,
}

pub use self::GenericPositionOrAuto as PositionOrAuto;

impl<Pos> PositionOrAuto<Pos> {
    /// Return `auto`.
    #[inline]
    pub fn auto() -> Self {
        PositionOrAuto::Auto
    }
}

/// A generic value for the `z-index` property.
#[derive(
    Animate,
    Clone,
    ComputeSquaredDistance,
    Copy,
    Debug,
    MallocSizeOf,
    PartialEq,
    Parse,
    SpecifiedValueInfo,
    ToAnimatedZero,
    ToComputedValue,
    ToCss,
    ToResolvedValue,
    ToShmem,
)]
#[repr(C, u8)]
pub enum GenericZIndex<I> {
    /// An integer value.
    Integer(I),
    /// The keyword `auto`.
    Auto,
}

pub use self::GenericZIndex as ZIndex;

impl<Integer> ZIndex<Integer> {
    /// Returns `auto`
    #[inline]
    pub fn auto() -> Self {
        ZIndex::Auto
    }

    /// Returns whether `self` is `auto`.
    #[inline]
    pub fn is_auto(self) -> bool {
        matches!(self, ZIndex::Auto)
    }

    /// Returns the integer value if it is an integer, or `auto`.
    #[inline]
    pub fn integer_or(self, auto: Integer) -> Integer {
        match self {
            ZIndex::Integer(n) => n,
            ZIndex::Auto => auto,
        }
    }
}