use std::collections::HashMap;

use gpui::Hsla;
use serde::{de::Error, Deserialize, Deserializer};

use crate::hsl;
use anyhow::Result;

pub trait Colorize: Sized {
    /// Returns a new color with the given opacity.
    ///
    /// The opacity is a value between 0.0 and 1.0, where 0.0 is fully transparent and 1.0 is fully opaque.
    fn opacity(&self, opacity: f32) -> Self;
    /// Returns a new color with each channel divided by the given divisor.
    ///
    /// The divisor in range of 0.0 .. 1.0
    fn divide(&self, divisor: f32) -> Self;
    /// Return inverted color
    fn invert(&self) -> Self;
    /// Return inverted lightness
    fn invert_l(&self) -> Self;
    /// Return a new color with the lightness increased by the given factor.
    ///
    /// factor range: 0.0 .. 1.0
    fn lighten(&self, amount: f32) -> Self;
    /// Return a new color with the darkness increased by the given factor.
    ///
    /// factor range: 0.0 .. 1.0
    fn darken(&self, amount: f32) -> Self;
    /// Return a new color with the same lightness and alpha but different hue and saturation.
    fn apply(&self, base_color: Self) -> Self;

    /// Mix two colors together, the `factor` is a value between 0.0 and 1.0 for first color.
    fn mix(&self, other: Self, factor: f32) -> Self;

    /// Convert the color to a hex string. For example, "#F8FAFC".
    fn to_hex(&self) -> String;
    /// Parse a hex string to a color.
    fn parse_hex(hex: &str) -> Result<Self>;
}

impl Colorize for Hsla {
    fn opacity(&self, factor: f32) -> Self {
        Self {
            a: self.a * factor.clamp(0.0, 1.0),
            ..*self
        }
    }

    fn divide(&self, divisor: f32) -> Self {
        Self {
            a: divisor,
            ..*self
        }
    }

    fn invert(&self) -> Self {
        Self {
            h: 1.0 - self.h,
            s: 1.0 - self.s,
            l: 1.0 - self.l,
            a: self.a,
        }
    }

    fn invert_l(&self) -> Self {
        Self {
            l: 1.0 - self.l,
            ..*self
        }
    }

    fn lighten(&self, factor: f32) -> Self {
        let l = self.l * (1.0 + factor.clamp(0.0, 1.0));

        Hsla { l, ..*self }
    }

    fn darken(&self, factor: f32) -> Self {
        let l = self.l * (1.0 - factor.clamp(0.0, 1.0));

        Self { l, ..*self }
    }

    fn apply(&self, new_color: Self) -> Self {
        Hsla {
            h: new_color.h,
            s: new_color.s,
            l: self.l,
            a: self.a,
        }
    }

    /// Reference:
    /// https://github.com/bevyengine/bevy/blob/85eceb022da0326b47ac2b0d9202c9c9f01835bb/crates/bevy_color/src/hsla.rs#L112
    fn mix(&self, other: Self, factor: f32) -> Self {
        let factor = factor.clamp(0.0, 1.0);
        let inv = 1.0 - factor;

        #[inline]
        fn lerp_hue(a: f32, b: f32, t: f32) -> f32 {
            let diff = (b - a + 180.0).rem_euclid(360.) - 180.;
            (a + diff * t).rem_euclid(360.0)
        }

        Hsla {
            h: lerp_hue(self.h * 360., other.h * 360., factor) / 360.,
            s: self.s * factor + other.s * inv,
            l: self.l * factor + other.l * inv,
            a: self.a * factor + other.a * inv,
        }
    }

    fn to_hex(&self) -> String {
        let rgb = self.to_rgb();

        if rgb.a < 1. {
            return format!(
                "#{:02X}{:02X}{:02X}{:02X}",
                ((rgb.r * 255.) as u32),
                ((rgb.g * 255.) as u32),
                ((rgb.b * 255.) as u32),
                ((self.a * 255.) as u32)
            );
        }

        format!(
            "#{:02X}{:02X}{:02X}",
            ((rgb.r * 255.) as u32),
            ((rgb.g * 255.) as u32),
            ((rgb.b * 255.) as u32)
        )
    }

    fn parse_hex(hex: &str) -> Result<Self> {
        let hex = hex.trim_start_matches('#');
        let len = hex.len();
        if len != 6 && len != 8 {
            return Err(anyhow::anyhow!("invalid hex color"));
        }

        let r = u8::from_str_radix(&hex[0..2], 16)? as f32 / 255.;
        let g = u8::from_str_radix(&hex[2..4], 16)? as f32 / 255.;
        let b = u8::from_str_radix(&hex[4..6], 16)? as f32 / 255.;
        let a = if len == 8 {
            u8::from_str_radix(&hex[6..8], 16)? as f32 / 255.
        } else {
            1.
        };

        let v = gpui::Rgba { r, g, b, a };
        let color: Hsla = v.into();
        Ok(color)
    }
}

pub(crate) static DEFAULT_COLOR: once_cell::sync::Lazy<ShadcnColors> =
    once_cell::sync::Lazy::new(|| {
        serde_json::from_str(include_str!("../default-colors.json"))
            .expect("failed to parse default-json")
    });

type ColorScales = HashMap<usize, ShadcnColor>;

mod color_scales {
    use std::collections::HashMap;

    use super::{ColorScales, ShadcnColor};

    use serde::de::{Deserialize, Deserializer};

    pub fn deserialize<'de, D>(deserializer: D) -> Result<ColorScales, D::Error>
    where
        D: Deserializer<'de>,
    {
        let mut map = HashMap::new();
        for color in Vec::<ShadcnColor>::deserialize(deserializer)? {
            map.insert(color.scale, color);
        }
        Ok(map)
    }
}

#[derive(Debug, Clone, PartialEq, Eq, serde::Deserialize)]
pub(crate) struct ShadcnColors {
    pub(crate) black: ShadcnColor,
    pub(crate) white: ShadcnColor,
    #[serde(with = "color_scales")]
    pub(crate) slate: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) gray: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) zinc: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) neutral: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) stone: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) red: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) orange: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) amber: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) yellow: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) lime: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) green: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) emerald: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) teal: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) cyan: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) sky: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) blue: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) indigo: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) violet: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) purple: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) fuchsia: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) pink: ColorScales,
    #[serde(with = "color_scales")]
    pub(crate) rose: ColorScales,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, serde::Deserialize)]
pub(crate) struct ShadcnColor {
    #[serde(default)]
    pub(crate) scale: usize,
    #[serde(deserialize_with = "from_hsl_channel", alias = "hslChannel")]
    pub(crate) hsla: Hsla,
}

/// Deserialize Hsla from a string in the format "210 40% 98%"
fn from_hsl_channel<'de, D>(deserializer: D) -> Result<Hsla, D::Error>
where
    D: Deserializer<'de>,
{
    let s: String = Deserialize::deserialize(deserializer).unwrap();

    let mut parts = s.split_whitespace();
    if parts.clone().count() != 3 {
        return Err(D::Error::custom(
            "expected hslChannel has 3 parts, e.g: '210 40% 98%'",
        ));
    }

    fn parse_number(s: &str) -> f32 {
        s.trim_end_matches('%')
            .parse()
            .expect("failed to parse number")
    }

    let (h, s, l) = (
        parse_number(parts.next().unwrap()),
        parse_number(parts.next().unwrap()),
        parse_number(parts.next().unwrap()),
    );

    Ok(hsl(h, s, l))
}

macro_rules! color_method {
    ($color:tt, $scale:tt) => {
        paste::paste! {
            #[inline]
            #[allow(unused)]
            pub fn [<$color _ $scale>]() -> Hsla {
                if let Some(color) = DEFAULT_COLOR.$color.get(&($scale as usize)) {
                    return color.hsla;
                }

                black()
            }
        }
    };
}

macro_rules! color_methods {
    ($color:tt) => {
        paste::paste! {
            /// Get color by scale number.
            ///
            /// The possible scale numbers are:
            /// 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 950
            ///
            /// If the scale number is not found, it will return black color.
            #[inline]
            pub fn [<$color>](scale: usize) -> Hsla {
                if let Some(color) = DEFAULT_COLOR.$color.get(&scale) {
                    return color.hsla;
                }

                black()
            }
        }

        color_method!($color, 50);
        color_method!($color, 100);
        color_method!($color, 200);
        color_method!($color, 300);
        color_method!($color, 400);
        color_method!($color, 500);
        color_method!($color, 600);
        color_method!($color, 700);
        color_method!($color, 800);
        color_method!($color, 900);
        color_method!($color, 950);
    };
}

pub fn black() -> Hsla {
    DEFAULT_COLOR.black.hsla
}

pub fn white() -> Hsla {
    DEFAULT_COLOR.white.hsla
}

color_methods!(slate);
color_methods!(gray);
color_methods!(zinc);
color_methods!(neutral);
color_methods!(stone);
color_methods!(red);
color_methods!(orange);
color_methods!(amber);
color_methods!(yellow);
color_methods!(lime);
color_methods!(green);
color_methods!(emerald);
color_methods!(teal);
color_methods!(cyan);
color_methods!(sky);
color_methods!(blue);
color_methods!(indigo);
color_methods!(violet);
color_methods!(purple);
color_methods!(fuchsia);
color_methods!(pink);
color_methods!(rose);

#[cfg(test)]
mod tests {
    use gpui::{rgb, rgba};

    use super::*;

    #[test]
    fn test_default_colors() {
        assert_eq!(white(), hsl(0.0, 0.0, 100.0));
        assert_eq!(black(), hsl(0.0, 0.0, 0.0));

        assert_eq!(slate_50(), hsl(210.0, 40.0, 98.0));
        assert_eq!(slate_100(), hsl(210.0, 40.0, 96.1));
        assert_eq!(slate_900(), hsl(222.2, 47.4, 11.2));

        assert_eq!(red_50(), hsl(0.0, 85.7, 97.3));
        assert_eq!(yellow_100(), hsl(54.9, 96.7, 88.0));
        assert_eq!(green_200(), hsl(141.0, 78.9, 85.1));
        assert_eq!(cyan_300(), hsl(187.0, 92.4, 69.0));
        assert_eq!(blue_400(), hsl(213.1, 93.9, 67.8));
        assert_eq!(indigo_500(), hsl(238.7, 83.5, 66.7));
    }

    #[test]
    fn test_to_hex_string() {
        let color: Hsla = rgb(0xf8fafc).into();
        assert_eq!(color.to_hex(), "#F8FAFC");

        let color: Hsla = rgb(0xfef2f2).into();
        assert_eq!(color.to_hex(), "#FEF2F2");

        let color: Hsla = rgba(0x0413fcaa).into();
        assert_eq!(color.to_hex(), "#0413FCAA");
    }

    #[test]
    fn test_from_hex_string() {
        let color: Hsla = Hsla::parse_hex("#F8FAFC").unwrap();
        assert_eq!(color, rgb(0xf8fafc).into());

        let color: Hsla = Hsla::parse_hex("#FEF2F2").unwrap();
        assert_eq!(color, rgb(0xfef2f2).into());

        let color: Hsla = Hsla::parse_hex("#0413FCAA").unwrap();
        assert_eq!(color, rgba(0x0413fcaa).into());
    }

    #[test]
    fn test_lighten() {
        let color = super::hsl(240.0, 5.0, 30.0);
        let color = color.lighten(0.5);
        assert_eq!(color.l, 0.45000002);
        let color = color.lighten(0.5);
        assert_eq!(color.l, 0.675);
        let color = color.lighten(0.1);
        assert_eq!(color.l, 0.7425);
    }

    #[test]
    fn test_darken() {
        let color = super::hsl(240.0, 5.0, 96.0);
        let color = color.darken(0.5);
        assert_eq!(color.l, 0.48);
        let color = color.darken(0.5);
        assert_eq!(color.l, 0.24);
    }

    #[test]
    fn test_mix() {
        let red = Hsla::parse_hex("#FF0000").unwrap();
        let blue = Hsla::parse_hex("#0000FF").unwrap();
        let green = Hsla::parse_hex("#00FF00").unwrap();
        let yellow = Hsla::parse_hex("#FFFF00").unwrap();

        assert_eq!(red.mix(blue, 0.5).to_hex(), "#FF00FF");
        assert_eq!(green.mix(red, 0.5).to_hex(), "#FFFF00");
        assert_eq!(blue.mix(yellow, 0.2).to_hex(), "#0098FF");
    }
}