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    //! Manipulate and convert CIE L\*a\*b\* and Lch colors.
    //!
    //! # Examples
    //!
    //! ```
    //! use deltae::*;
    //!
    //! let lab0: LabValue = "95.08, -0.17, -10.81".parse().unwrap();
    //! let lch0 = LchValue {
    //!     l: 95.08,
    //!     c: 10.811337,
    //!     h: 269.09903,
    //! };
    //!
    //! assert!(lab0.delta_eq(&lch0, DE2000, 0.01));
    //!
    //! let lch0 = LchValue::from(lab0);
    //! let lab2 = LabValue::from(lch0);
    //!
    //! println!("{}", lch0); // [L:89.73, c:7.2094, h:285.1157]
    //!
    //! assert_eq!(lab0.round_to(4), lab2.round_to(4));
    //! ```

    use std::fmt;
    use std::error::Error;

    use crate::*;

    /// # CIEL\*a\*b\*
    ///
    /// The [`LabValue`] is the key component in calculating [`DeltaE`]
    ///
    /// | `Value` | `Color`               | `Range`              |
    /// |:-------:|:---------------------:|:--------------------:|
    /// | `L*`    | `Light <---> Dark`    | `0.0 <---> 100.0`    |
    /// | `a*`    | `Green <---> Magenta` | `-128.0 <---> 128.0` |
    /// | `b*`    | `Blue  <---> Yellow`  | `-128.0 <---> 128.0` |
    ///
    #[derive(Debug, Clone, Copy, PartialEq)]
    pub struct LabValue {
        /// Lightness
        pub l: f32,
        /// Green - Magenta
        pub a: f32,
        /// Blue - Yellow
        pub b: f32,
    }

    impl LabValue {
        /// Returns a result of a LabValue from 3 `f32`s.
        /// Will return `Err()` if the values are out of range as determined by the [`Validate`] trait.
        pub fn new(l: f32, a: f32, b: f32) -> ValueResult<LabValue> {
            LabValue {l, a, b}.validate()
        }
    }

    impl Default for LabValue {
        fn default() -> LabValue {
            LabValue { l: 0.0, a: 0.0, b: 0.0 }
        }
    }

    impl fmt::Display for LabValue {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            write!(f, "[L:{}, a:{}, b:{}]", self.l, self.a, self.b)
        }
    }

    /// # Lch: Luminance, Chroma, Hue
    ///
    /// | `Value` | `Color`                    | `Range`                |
    /// |:-------:|:--------------------------:|:----------------------:|
    /// | `L*`    | `Light <---> Dark`         | `0.0 <---> 100.0`      |
    /// | `c`     | `Chroma (Amount of color)` | `0.0 <---> 181.0139`   |
    /// | `h`     | `Hue (Degrees)`            | `0.0 <---> 360.0°`     |
    ///
    #[derive(Debug, Clone, Copy, PartialEq)]
    pub struct LchValue {
        /// Lightness
        pub l: f32,
        /// Chroma
        pub c: f32,
        /// Hue (in degrees)
        pub h: f32,
    }

    impl LchValue {
        /// Returns a result of an LchValue from 3 `f32`s.
        /// Will return `Err()` if the values are out of range as determined by the [`Validate`] trait.
        pub fn new(l: f32, c: f32, h: f32) -> ValueResult<LchValue> {
            LchValue { l, c, h }.validate()
        }

        /// Returns the Hue as radians rather than degrees
        pub fn hue_radians(&self) -> f32 {
            self.h.to_radians()
        }
    }

    impl Default for LchValue {
        fn default() -> LchValue {
            LchValue { l: 0.0, c: 0.0, h: 0.0 }
        }
    }

    impl fmt::Display for LchValue {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            write!(f, "[L:{}, c:{}, h:{}]", self.l, self.c, self.h)
        }
    }

    /// # CIE 1931 XYZ
    ///
    /// Further Reading: [https://en.wikipedia.org/wiki/CIE_1931_color_space](https://en.wikipedia.org/wiki/CIE_1931_color_space)
    ///
    /// | `Value` | `Color`     | `Range`         |
    /// |:-------:|:-----------:|:---------------:|
    /// | `X`     | `RGB`       | `0.0 <---> 1.0` |
    /// | `Y`     | `Luminance` | `0.0 <---> 1.0` |
    /// | `Z`     | `Blue`      | `0.0 <---> 1.0` |
    ///
    #[derive(Debug, Clone, Copy, PartialEq)]
    pub struct XyzValue {
        /// X Value
        pub x: f32,
        /// Y Value
        pub y: f32,
        /// Z Value
        pub z: f32,
    }

    impl XyzValue {
        /// Returns a result of an XyzValue from 3 `f32`s.
        /// Will return `Err()` if the values are out of range as determined by the [`Validate`] trait.
        pub fn new(x: f32, y: f32, z:f32) -> ValueResult<XyzValue> {
            XyzValue {x, y, z}.validate()
        }
    }

    impl Default for XyzValue {
        fn default() -> XyzValue {
            XyzValue { x: 0.0, y: 0.0, z: 0.0 }
        }
    }

    impl fmt::Display for XyzValue {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            write!(f, "[X:{}, Y:{}, Z:{}]", self.x, self.y, self.z)
        }
    }

    #[derive(Debug)]
    /// Value validation Error type
    pub enum ValueError {
        /// The value is outside the acceptable range
        OutOfBounds,
        /// The value is formatted incorrectly
        BadFormat,
    }

    impl fmt::Display for ValueError {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            write!(f, "{}", self.description())
        }
    }

    impl ValueError {
        fn description(&self) -> &str {
            match self {
                ValueError::OutOfBounds => "Value is out of range!",
                ValueError::BadFormat   => "Value is malformed!",
            }
        }
    }

    impl Error for ValueError {}