use std::{convert::AsRef, convert::TryFrom, result::Result, str::FromStr};

#[cfg(feature = "serde")]
use serde::{Deserialize, Serialize};

/// Represents a color.
///
/// # Platform-specific Notes
///
/// The following list of 16 base colors are available for almost all terminals (Windows 7 and 8 included).
///
/// | Light | Dark |
/// | :--| :--   |
/// | `Grey` | `Black` |
/// | `Red` | `DarkRed` |
/// | `Green` | `DarkGreen` |
/// | `Yellow` | `DarkYellow` |
/// | `Blue` | `DarkBlue` |
/// | `Magenta` | `DarkMagenta` |
/// | `Cyan` | `DarkCyan` |
/// | `White` | `DarkWhite` |
///
/// Most UNIX terminals and Windows 10 consoles support additional colors.
/// See [`Color::Rgb`](enum.Color.html#variant.Rgb) or [`Color::AnsiValue`](enum.Color.html#variant.AnsiValue) for
/// more info.
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
#[derive(Copy, Clone, Debug, PartialEq, Eq, Ord, PartialOrd, Hash)]
pub enum Color {
    /// Resets the terminal color.
    Reset,

    /// Black color.
    Black,

    /// Dark grey color.
    DarkGrey,

    /// Light red color.
    Red,

    /// Dark red color.
    DarkRed,

    /// Light green color.
    Green,

    /// Dark green color.
    DarkGreen,

    /// Light yellow color.
    Yellow,

    /// Dark yellow color.
    DarkYellow,

    /// Light blue color.
    Blue,

    /// Dark blue color.
    DarkBlue,

    /// Light magenta color.
    Magenta,

    /// Dark magenta color.
    DarkMagenta,

    /// Light cyan color.
    Cyan,

    /// Dark cyan color.
    DarkCyan,

    /// White color.
    White,

    /// Grey color.
    Grey,

    /// An RGB color. See [RGB color model](https://en.wikipedia.org/wiki/RGB_color_model) for more info.
    ///
    /// Most UNIX terminals and Windows 10 supported only.
    /// See [Platform-specific notes](enum.Color.html#platform-specific-notes) for more info.
    Rgb { r: u8, g: u8, b: u8 },

    /// An ANSI color. See [256 colors - cheat sheet](https://jonasjacek.github.io/colors/) for more info.
    ///
    /// Most UNIX terminals and Windows 10 supported only.
    /// See [Platform-specific notes](enum.Color.html#platform-specific-notes) for more info.
    AnsiValue(u8),
}

impl TryFrom<&str> for Color {
    type Error = ();

    /// Try to create a `Color` from the string representation. This returns an error if the string does not match.
    fn try_from(src: &str) -> Result<Self, Self::Error> {
        let src = src.to_lowercase();

        match src.as_ref() {
            "black" => Ok(Color::Black),
            "dark_grey" => Ok(Color::DarkGrey),
            "red" => Ok(Color::Red),
            "dark_red" => Ok(Color::DarkRed),
            "green" => Ok(Color::Green),
            "dark_green" => Ok(Color::DarkGreen),
            "yellow" => Ok(Color::Yellow),
            "dark_yellow" => Ok(Color::DarkYellow),
            "blue" => Ok(Color::Blue),
            "dark_blue" => Ok(Color::DarkBlue),
            "magenta" => Ok(Color::Magenta),
            "dark_magenta" => Ok(Color::DarkMagenta),
            "cyan" => Ok(Color::Cyan),
            "dark_cyan" => Ok(Color::DarkCyan),
            "white" => Ok(Color::White),
            "grey" => Ok(Color::Grey),
            _ => Err(()),
        }
    }
}

impl FromStr for Color {
    type Err = ();

    /// Creates a `Color` from the string representation.
    ///
    /// # Notes
    ///
    /// * Returns `Color::White` in case of an unknown color.
    /// * Does not return `Err` and you can safely unwrap.
    fn from_str(src: &str) -> Result<Self, Self::Err> {
        Ok(Color::try_from(src).unwrap_or(Color::White))
    }
}

#[cfg(test)]
mod tests {
    use super::Color;

    #[test]
    fn test_known_color_conversion() {
        assert_eq!("black".parse(), Ok(Color::Black));
        assert_eq!("dark_grey".parse(), Ok(Color::DarkGrey));
        assert_eq!("red".parse(), Ok(Color::Red));
        assert_eq!("dark_red".parse(), Ok(Color::DarkRed));
        assert_eq!("green".parse(), Ok(Color::Green));
        assert_eq!("dark_green".parse(), Ok(Color::DarkGreen));
        assert_eq!("yellow".parse(), Ok(Color::Yellow));
        assert_eq!("dark_yellow".parse(), Ok(Color::DarkYellow));
        assert_eq!("blue".parse(), Ok(Color::Blue));
        assert_eq!("dark_blue".parse(), Ok(Color::DarkBlue));
        assert_eq!("magenta".parse(), Ok(Color::Magenta));
        assert_eq!("dark_magenta".parse(), Ok(Color::DarkMagenta));
        assert_eq!("cyan".parse(), Ok(Color::Cyan));
        assert_eq!("dark_cyan".parse(), Ok(Color::DarkCyan));
        assert_eq!("white".parse(), Ok(Color::White));
        assert_eq!("grey".parse(), Ok(Color::Grey));
    }

    #[test]
    fn test_unknown_color_conversion_yields_white() {
        assert_eq!("foo".parse(), Ok(Color::White));
    }
}