#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Config
{
    pub source_factor: Factor,
    pub destination_factor: Factor,
    pub equation: Equation,
}

impl Default for Config
{
    fn default() -> Self
    {
        Self {
            source_factor: Factor::One,
            destination_factor: Factor::Zero,
            equation: Equation::default(),
        }
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
#[non_exhaustive]
pub enum Factor
{
    /// Factor will be the RGBA color `(0,0,0,0)`
    Zero,

    /// Factor will be the RGBA color `(1,1,1,1)`
    One,

    /// Factor will be the source color
    SrcColor,

    /// Factor will be the RGBA color `(1,1,1,1) - source color`
    OneMinusSrcColor,

    /// Factor will be the destination color
    DstColor,

    /// Factor will be the RGBA color `(1,1,1,1) - destination color`
    OneMinusDstColor,

    /// Factor will be the alpha component of the source color.
    SrcAlpha,

    /// Factor will be the RGBA color `(1,1,1,1) - source color alpha`
    OneMinusSrcAlpha,

    /// Factor will be the alpha component of the destination color.
    DstAlpha,

    /// Factor will be the RGBA color `(1,1,1,1) - destination color alpha`
    OneMinusDstAlpha,

    /// Factor will be the constant color
    ConstantColor,

    /// Factor will be the RGBA color `(1,1,1,1) - constant color`
    OneMinusConstantColor,

    /// Factor will be the alpha component of the constant color.
    ConstantAlpha,

    /// Factor will be the RGBA color `(1,1,1,1) - constant color alpha`
    OneMinusConstantAlpha,
}

#[derive(Debug, Default, Clone, Copy, PartialEq, Eq)]
pub enum Equation
{
    /// The destination color and source color is added to each other in the blend
    /// function
    #[default]
    Add,

    /// The destination color is subtracted from the source color in the blend function
    Subtract,

    /// The source color is subtracted from the destination color in the blend function
    ReverseSubtract,

    /// The blend function will take the component-wise minimum of the destination color
    /// and the source color
    Min,

    /// The blend function will take the component-wise maximum of the destination color
    /// and the source color
    Max,
}