use serde::{de::Visitor, Deserialize, Serialize};
use std::ops::Deref;

use termion::color;

#[derive(Clone, Copy, Debug, Serialize, Deserialize)]
pub struct Theme {
    pub windows: Colors,
    pub frames: Frames,
}

#[derive(Clone, Copy, Debug, Serialize, Deserialize)]
pub struct ColorSet {
    pub fg: Color,
    pub bg: Color,
}

#[derive(Clone, Copy, Debug, Serialize, Deserialize)]
pub struct Frames {
    pub outer: Frame,
    pub inner: Frame,
}

#[derive(Clone, Copy, Debug, Serialize, Deserialize)]
pub struct FrameChars {
    pub top: char,
    pub bottom: char,
    pub left: char,
    pub right: char,
}

#[derive(Clone, Copy, Debug, Serialize, Deserialize)]
pub struct Frame {
    pub width: u16,
    pub frame_chars: FrameChars,
    pub color: ColorSet,
}

impl Default for ColorSet {
    fn default() -> Self {
        Self {
            fg: "#ffffff".try_into().unwrap(),
            bg: "#000000".try_into().unwrap(),
        }
    }
}

impl ToString for ColorSet {
    #[inline(always)]
    fn to_string(&self) -> String {
        self.bg.bg_string() + &self.fg.fg_string()
    }
}

#[derive(Clone, Copy, Debug, Serialize, Deserialize)]
pub struct Colors {
    pub primary: ColorSet,
    pub subwin: ColorSet,
    pub highlight: ColorSet,
}

#[derive(Clone, Copy, Debug)]
pub struct Color(color::Rgb);

impl Serialize for Color {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: serde::Serializer,
    {
        let rgb = self.0;
        serializer.serialize_str(&format!(
            "#{:02X}{:02X}{:02X}",
            rgb.0, rgb.1, rgb.2,
        ))
    }
}

impl<'de> Deserialize<'de> for Color {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: serde::Deserializer<'de>,
    {
        struct ColorCodeVisitor;
        impl<'de> Visitor<'de> for ColorCodeVisitor {
            fn expecting(
                &self,
                formatter: &mut std::fmt::Formatter,
            ) -> std::fmt::Result {
                formatter.write_str("hex color code")
            }
            type Value = Color;

            fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
            where
                E: serde::de::Error,
            {
                match TryInto::<Color>::try_into(v) {
                    Ok(c) => Ok(c),
                    Err(e) => Err(E::custom(e.to_string())),
                }
            }

            fn visit_string<E>(
                self,
                v: String,
            ) -> Result<Self::Value, E>
            where
                E: serde::de::Error,
            {
                match TryInto::<Color>::try_into(v) {
                    Ok(c) => Ok(c),
                    Err(e) => Err(E::custom(e.to_string())),
                }
            }
        }
        deserializer.deserialize_any(ColorCodeVisitor {})
    }
}

impl Deref for Color {
    type Target = color::Rgb;

    fn deref(&self) -> &Self::Target {
        &self.0
    }
}
impl TryFrom<String> for Color {
    type Error = anyhow::Error;

    fn try_from(value: String) -> Result<Self, Self::Error> {
        Ok(value.as_str().try_into()?)
    }
}

impl TryFrom<&str> for Color {
    type Error = anyhow::Error;

    fn try_from(value: &str) -> Result<Self, Self::Error> {
        if value.len() < 6 || value.len() > 7 {
            panic!("hex code length invalid: {}", value.len());
        }
        let mut i = 0;
        if value.starts_with('#') {
            i = 1;
        }
        Ok(Self(color::Rgb(
            u8::from_str_radix(&value[i..i + 2], 16)
                .map_err(|_| anyhow::anyhow!("red hex"))?,
            u8::from_str_radix(&value[i + 2..i + 4], 16)
                .map_err(|_| anyhow::anyhow!("green hex"))?,
            u8::from_str_radix(&value[i + 4..i + 6], 16)
                .map_err(|_| anyhow::anyhow!("blue hex"))?,
        )))
    }
}

impl Default for Theme {
    fn default() -> Self {
        Self {
            windows: Colors {
                primary: ColorSet {
                    fg: "#330033".try_into().unwrap(),
                    bg: "#a006d3".try_into().unwrap(),
                },
                highlight: ColorSet {
                    fg: "#ffffff".try_into().unwrap(),
                    bg: "#0000ff".try_into().unwrap(),
                },
                subwin: ColorSet {
                    fg: "#ffffff".try_into().unwrap(),
                    bg: "#500170".try_into().unwrap(),
                },
            },
            frames: Frames {
                outer: Frame {
                    color: ColorSet {
                        fg: "#ff36ff".try_into().unwrap(),
                        bg: "#9005c2".try_into().unwrap(),
                    },
                    frame_chars: FrameChars {
                        top: ' ',
                        bottom: ' ',
                        left: ' ',
                        right: ' ',
                    },
                    width: 1,
                },
                inner: Frame {
                    color: ColorSet {
                        fg: "#ffe6ff".try_into().unwrap(),
                        bg: "#7003a0".try_into().unwrap(),
                    },
                    frame_chars: FrameChars {
                        top: ' ',
                        bottom: ' ',
                        left: ' ',
                        right: ' ',
                    },
                    width: 1,
                },
            },
        }
    }
}

impl Theme {
    #[inline(always)]
    pub fn primary(&self) -> String {
        self.windows.primary.to_string()
    }

    #[inline(always)]
    pub fn frame(&self) -> String {
        self.frames.outer.color.to_string()
    }
}