libcosmic/cosmic-theme/src/model/theme.rs

use crate::{
    steps::steps, Component, Container, CornerRadii, CosmicPalette, CosmicPaletteInner, Spacing,
    DARK_PALETTE, LIGHT_PALETTE, NAME, THEME_DIR,
};
use anyhow::Context;
use cosmic_config::{Config, ConfigGet, ConfigSet, CosmicConfigEntry};
use directories::{BaseDirsExt, ProjectDirsExt};
use palette::{FromColor, Oklcha, Srgb, Srgba};
use serde::{de::DeserializeOwned, Deserialize, Serialize};
use std::{
    fmt,
    fs::File,
    io::Write,
    path::{Path, PathBuf},
};

#[derive(Clone, Copy, Debug, Default, Deserialize, Serialize, PartialEq, Eq)]
/// Theme layer type
pub enum Layer {
    /// Background layer
    #[default]
    Background,
    /// Primary Layer
    Primary,
    /// Secondary Layer
    Secondary,
}

/// Cosmic Theme data structure with all colors and its name
#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Eq)]
pub struct Theme<C> {
    /// name of the theme
    pub name: String,
    /// background element colors
    pub background: Container<C>,
    /// primary element colors
    pub primary: Container<C>,
    /// secondary element colors
    pub secondary: Container<C>,
    /// accent element colors
    pub accent: Component<C>,
    /// suggested element colors
    pub success: Component<C>,
    /// destructive element colors
    pub destructive: Component<C>,
    /// warning element colors
    pub warning: Component<C>,
    /// palette
    pub palette: CosmicPaletteInner<C>,
    /// spacing
    pub spacing: Spacing,
    /// corner radii
    pub corner_radii: CornerRadii,
    /// is dark
    pub is_dark: bool,
    /// is high contrast
    pub is_high_contrast: bool,
}

impl CosmicConfigEntry for Theme<Srgba> {
    fn write_entry(&self, config: &Config) -> Result<(), cosmic_config::Error> {
        let self_ = self.clone();
        // TODO do as transaction
        let tx = config.transaction();

        tx.set("name", self_.name)?;
        tx.set("background", self_.background)?;
        tx.set("primary", self_.primary)?;
        tx.set("secondary", self_.secondary)?;
        tx.set("accent", self_.accent)?;
        tx.set("success", self_.success)?;
        tx.set("destructive", self_.destructive)?;
        tx.set("warning", self_.warning)?;
        tx.set("palette", self_.palette)?;
        tx.set("is_dark", self_.is_dark)?;
        tx.set("is_high_contrast", self_.is_high_contrast)?;

        tx.commit()
    }

    fn get_entry(config: &Config) -> Result<Self, (Vec<cosmic_config::Error>, Self)> {
        let mut default = Self::default();
        let mut errors = Vec::new();

        match config.get::<String>("name") {
            Ok(name) => default.name = name,
            Err(e) => errors.push(e),
        }
        match config.get::<Container<Srgba>>("background") {
            Ok(background) => default.background = background,
            Err(e) => errors.push(e),
        }
        match config.get::<Container<Srgba>>("primary") {
            Ok(primary) => default.primary = primary,
            Err(e) => errors.push(e),
        }
        match config.get::<Container<Srgba>>("secondary") {
            Ok(secondary) => default.secondary = secondary,
            Err(e) => errors.push(e),
        }
        match config.get::<Component<Srgba>>("accent") {
            Ok(accent) => default.accent = accent,
            Err(e) => errors.push(e),
        }
        match config.get::<Component<Srgba>>("success") {
            Ok(success) => default.success = success,
            Err(e) => errors.push(e),
        }
        match config.get::<Component<Srgba>>("destructive") {
            Ok(destructive) => default.destructive = destructive,
            Err(e) => errors.push(e),
        }
        match config.get::<Component<Srgba>>("warning") {
            Ok(warning) => default.warning = warning,
            Err(e) => errors.push(e),
        }
        match config.get::<CosmicPaletteInner<Srgba>>("palette") {
            Ok(palette) => default.palette = palette,
            Err(e) => errors.push(e),
        }
        match config.get::<bool>("is_dark") {
            Ok(is_dark) => default.is_dark = is_dark,
            Err(e) => errors.push(e),
        }
        match config.get::<bool>("is_high_contrast") {
            Ok(is_high_contrast) => default.is_high_contrast = is_high_contrast,
            Err(e) => errors.push(e),
        }
        match config.get::<Spacing>("spacing") {
            Ok(spacing) => default.spacing = spacing,
            Err(e) => errors.push(e),
        }
        match config.get::<CornerRadii>("corner_radii") {
            Ok(corner_radii) => default.corner_radii = corner_radii,
            Err(e) => errors.push(e),
        }

        if errors.is_empty() {
            Ok(default)
        } else {
            Err((errors, default))
        }
    }
}

impl Default for Theme<Srgba> {
    fn default() -> Self {
        Self::dark_default()
    }
}

/// Trait for layered themes
pub trait LayeredTheme {
    /// Set the layer of the theme
    fn set_layer(&mut self, layer: Layer);
}

impl<C> Theme<C> {
    /// version of the theme
    pub fn version() -> u64 {
        1
    }

    /// id of the theme
    pub fn id() -> &'static str {
        NAME
    }
}

impl<C> Theme<C>
where
    C: Clone + fmt::Debug + Default + Into<Srgba> + From<Srgba> + Serialize + DeserializeOwned,
{
    /// Convert the theme to a high-contrast variant
    pub fn to_high_contrast(&self) -> Self {
        todo!();
    }

    /// save the theme to the theme directory
    pub fn save(&self) -> anyhow::Result<()> {
        let ron_path: PathBuf = [NAME, THEME_DIR].iter().collect();
        let ron_dirs = directories::ProjectDirs::from_path(ron_path)
            .context("Failed to get project directories.")?;
        let ron_name = format!("{}.ron", &self.name);

        if let Ok(p) = ron_dirs.place_config_file(ron_name) {
            let mut f = File::create(p)?;
            f.write_all(ron::ser::to_string_pretty(self, Default::default())?.as_bytes())?;
        } else {
            anyhow::bail!("Failed to write RON theme.");
        }
        Ok(())
    }

    /// init the theme directory
    pub fn init() -> anyhow::Result<PathBuf> {
        let ron_path: PathBuf = [NAME, THEME_DIR].iter().collect();
        let base_dirs = directories::BaseDirs::new().context("Failed to get base directories.")?;
        Ok(base_dirs.create_config_directory(ron_path)?)
    }

    /// load a theme by name
    pub fn load_from_name(name: &str) -> anyhow::Result<Self> {
        let ron_path: PathBuf = [NAME, THEME_DIR].iter().collect();
        let ron_dirs = directories::ProjectDirs::from_path(ron_path)
            .context("Failed to get project directories.")?;

        let ron_name = format!("{}.ron", name);
        if let Some(p) = ron_dirs.find_config_file(ron_name) {
            let f = File::open(p)?;
            Ok(ron::de::from_reader(f)?)
        } else {
            anyhow::bail!("Failed to write RON theme.");
        }
    }

    /// load a theme by path
    pub fn load(p: &dyn AsRef<Path>) -> anyhow::Result<Self> {
        let f = File::open(p)?;
        Ok(ron::de::from_reader(f)?)
    }

    // TODO convenient getter functions for each named color variable
    /// get @accent_color
    pub fn accent_color(&self) -> Srgba {
        self.accent.base.clone().into()
    }
    /// get @success_color
    pub fn success_color(&self) -> Srgba {
        self.success.base.clone().into()
    }
    /// get @destructive_color
    pub fn destructive_color(&self) -> Srgba {
        self.destructive.base.clone().into()
    }
    /// get @warning_color
    pub fn warning_color(&self) -> Srgba {
        self.warning.base.clone().into()
    }

    // Containers
    /// get @bg_color
    pub fn bg_color(&self) -> Srgba {
        self.background.base.clone().into()
    }
    /// get @bg_component_color
    pub fn bg_component_color(&self) -> Srgba {
        self.background.component.base.clone().into()
    }
    /// get @primary_container_color
    pub fn primary_container_color(&self) -> Srgba {
        self.primary.base.clone().into()
    }
    /// get @primary_component_color
    pub fn primary_component_color(&self) -> Srgba {
        self.primary.component.base.clone().into()
    }
    /// get @secondary_container_color
    pub fn secondary_container_color(&self) -> Srgba {
        self.secondary.base.clone().into()
    }
    /// get @secondary_component_color
    pub fn secondary_component_color(&self) -> Srgba {
        self.secondary.component.base.clone().into()
    }

    // Text
    /// get @on_bg_color
    pub fn on_bg_color(&self) -> Srgba {
        self.background.on.clone().into()
    }
    /// get @on_bg_component_color
    pub fn on_bg_component_color(&self) -> Srgba {
        self.background.component.on.clone().into()
    }
    /// get @on_primary_color
    pub fn on_primary_container_color(&self) -> Srgba {
        self.primary.on.clone().into()
    }
    /// get @on_primary_component_color
    pub fn on_primary_component_color(&self) -> Srgba {
        self.primary.component.on.clone().into()
    }
    /// get @on_secondary_color
    pub fn on_secondary_container_color(&self) -> Srgba {
        self.secondary.on.clone().into()
    }
    /// get @on_secondary_component_color
    pub fn on_secondary_component_color(&self) -> Srgba {
        self.secondary.component.on.clone().into()
    }
    /// get @accent_text_color
    pub fn accent_text_color(&self) -> Srgba {
        self.accent.base.clone().into()
    }
    /// get @success_text_color
    pub fn success_text_color(&self) -> Srgba {
        self.success.base.clone().into()
    }
    /// get @warning_text_color
    pub fn warning_text_color(&self) -> Srgba {
        self.warning.base.clone().into()
    }
    /// get @destructive_text_color
    pub fn destructive_text_color(&self) -> Srgba {
        self.destructive.base.clone().into()
    }
    /// get @on_accent_color
    pub fn on_accent_color(&self) -> Srgba {
        self.accent.on.clone().into()
    }
    /// get @on_success_color
    pub fn on_success_color(&self) -> Srgba {
        self.success.on.clone().into()
    }
    /// get @oon_warning_color
    pub fn on_warning_color(&self) -> Srgba {
        self.warning.on.clone().into()
    }
    /// get @on_destructive_color
    pub fn on_destructive_color(&self) -> Srgba {
        self.destructive.on.clone().into()
    }

    // Borders and Dividers
    /// get @bg_divider
    pub fn bg_divider(&self) -> Srgba {
        self.background.divider.clone().into()
    }
    /// get @bg_component_divider
    pub fn bg_component_divider(&self) -> Srgba {
        self.background.component.divider.clone().into()
    }
    /// get @primary_container_divider
    pub fn primary_container_divider(&self) -> Srgba {
        self.primary.divider.clone().into()
    }
    /// get @primary_component_divider
    pub fn primary_component_divider(&self) -> Srgba {
        self.primary.component.divider.clone().into()
    }
    /// get @secondary_container_divider
    pub fn secondary_container_divider(&self) -> Srgba {
        self.secondary.divider.clone().into()
    }
    /// get @secondary_component_divider
    pub fn secondary_component_divider(&self) -> Srgba {
        self.secondary.component.divider.clone().into()
    }

    /// get @window_header_bg
    pub fn window_header_bg(&self) -> Srgba {
        self.background.base.clone().into()
    }

    /// get @space_none
    pub fn space_none(&self) -> u16 {
        self.spacing.space_none
    }
    /// get @space_xxxs
    pub fn space_xxxs(&self) -> u16 {
        self.spacing.space_xxxs
    }
    /// get @space_xxs
    pub fn space_xxs(&self) -> u16 {
        self.spacing.space_xxs
    }
    /// get @space_xs
    pub fn space_xs(&self) -> u16 {
        self.spacing.space_xs
    }
    /// get @space_s
    pub fn space_s(&self) -> u16 {
        self.spacing.space_s
    }
    /// get @space_m
    pub fn space_m(&self) -> u16 {
        self.spacing.space_m
    }
    /// get @space_l
    pub fn space_l(&self) -> u16 {
        self.spacing.space_l
    }
    /// get @space_xl
    pub fn space_xl(&self) -> u16 {
        self.spacing.space_xl
    }
    /// get @space_xxl
    pub fn space_xxl(&self) -> u16 {
        self.spacing.space_xxl
    }
    /// get @space_xxxl
    pub fn space_xxxl(&self) -> u16 {
        self.spacing.space_xxxl
    }

    /// get @radius_0
    pub fn radius_0(&self) -> [u16; 4] {
        self.corner_radii.radius_0
    }
    /// get @radius_xs
    pub fn radius_xs(&self) -> [u16; 4] {
        self.corner_radii.radius_xs
    }
    /// get @radius_s
    pub fn radius_s(&self) -> [u16; 4] {
        self.corner_radii.radius_s
    }
    /// get @radius_m
    pub fn radius_m(&self) -> [u16; 4] {
        self.corner_radii.radius_m
    }
    /// get @radius_l
    pub fn radius_l(&self) -> [u16; 4] {
        self.corner_radii.radius_l
    }
    /// get @radius_xl
    pub fn radius_xl(&self) -> [u16; 4] {
        self.corner_radii.radius_xl
    }
}

impl Theme<Srgba> {
    /// get the built in light theme
    pub fn light_default() -> Self {
        LIGHT_PALETTE.clone().into()
    }

    /// get the built in dark theme
    pub fn dark_default() -> Self {
        DARK_PALETTE.clone().into()
    }

    /// get the built in high contrast dark theme
    pub fn high_contrast_dark_default() -> Self {
        CosmicPalette::HighContrastDark(DARK_PALETTE.as_ref().clone()).into()
    }

    /// get the built in high contrast light theme
    pub fn high_contrast_light_default() -> Self {
        CosmicPalette::HighContrastLight(LIGHT_PALETTE.as_ref().clone()).into()
    }
}

impl<C> From<CosmicPalette<C>> for Theme<Srgba>
where
    CosmicPalette<C>: Into<CosmicPalette<Srgba>>,
{
    fn from(p: CosmicPalette<C>) -> Self {
        ThemeBuilder::palette(p.into()).build()
    }
}

/// Helper for building customized themes
#[derive(Debug, Serialize, Deserialize)]
pub struct ThemeBuilder {
    palette: CosmicPalette<Srgba>,
    spacing: Spacing,
    corner_radii: CornerRadii,
    neutral_tint: Option<Srgb>,
    bg_color: Option<Srgba>,
    primary_container_bg: Option<Srgba>,
    secondary_container_bg: Option<Srgba>,
    text_tint: Option<Srgb>,
    accent: Option<Srgb>,
}

impl Default for ThemeBuilder {
    fn default() -> Self {
        Self {
            palette: DARK_PALETTE.to_owned().into(),
            spacing: Spacing::default(),
            corner_radii: CornerRadii::default(),
            neutral_tint: Default::default(),
            text_tint: Default::default(),
            bg_color: Default::default(),
            primary_container_bg: Default::default(),
            secondary_container_bg: Default::default(),
            accent: Default::default(),
        }
    }
}

impl ThemeBuilder {
    /// Get a builder that is initialized with the default dark theme
    pub fn dark() -> Self {
        Self {
            palette: DARK_PALETTE.to_owned().into(),
            ..Default::default()
        }
    }

    /// Get a builder that is initialized with the default light theme
    pub fn light() -> Self {
        Self {
            palette: LIGHT_PALETTE.to_owned().into(),
            ..Default::default()
        }
    }

    /// Get a builder that is initialized with the default dark high contrast theme
    pub fn dark_high_contrast() -> Self {
        let palette: CosmicPalette<Srgba> = DARK_PALETTE.to_owned().into();
        Self {
            palette: CosmicPalette::HighContrastLight(palette.inner()),
            ..Default::default()
        }
    }

    /// Get a builder that is initialized with the default light high contrast theme
    pub fn light_high_contrast() -> Self {
        let palette: CosmicPalette<Srgba> = LIGHT_PALETTE.to_owned().into();
        Self {
            palette: CosmicPalette::HighContrastLight(palette.inner()),
            ..Default::default()
        }
    }

    /// Get a builder that is initialized with the provided palette
    pub fn palette(palette: CosmicPalette<Srgba>) -> Self {
        Self {
            palette,
            ..Default::default()
        }
    }

    /// set the spacing of the builder
    pub fn spacing(mut self, spacing: Spacing) -> Self {
        self.spacing = spacing;
        self
    }

    /// set the corner_radii of the builder
    pub fn corner_radii(mut self, corner_radii: CornerRadii) -> Self {
        self.corner_radii = corner_radii;
        self
    }

    /// apply a neutral tint to the palette
    pub fn neutral_tint(mut self, tint: Srgb) -> Self {
        self.neutral_tint = Some(tint);
        self
    }

    /// apply a text tint to the palette
    pub fn text_tint(mut self, tint: Srgb) -> Self {
        self.text_tint = Some(tint);
        self
    }

    /// apply a background color to the palette
    pub fn bg_color(mut self, c: Srgba) -> Self {
        self.bg_color = Some(c);
        self
    }

    /// apply a primary container background color to the palette
    pub fn primary_container_bg(mut self, c: Srgba) -> Self {
        self.primary_container_bg = Some(c);
        self
    }

    /// apply a accent color to the palette
    pub fn accent(mut self, c: Srgb) -> Self {
        self.accent = Some(c);
        self
    }

    /// build the theme
    pub fn build(self) -> Theme<Srgba> {
        let Self {
            mut palette,
            spacing,
            corner_radii,
            neutral_tint,
            text_tint,
            bg_color,
            primary_container_bg,
            secondary_container_bg,
            accent,
        } = self;

        if let Some(accent) = accent {
            palette.as_mut().accent = accent.into();
        }

        // TODO apply the tint customizations

        let is_dark = palette.is_dark();
        let is_high_contrast = palette.is_high_contrast();

        if let Some(accent) = accent {
            palette.as_mut().accent = accent.into();
        }
        let p_ref = palette.as_ref();

        let bg = if let Some(bg_color) = bg_color {
            bg_color
        } else {
            p_ref.gray_1.clone()
        };
        let ok_bg = Oklcha::from_color(bg);
        let step_array = steps(ok_bg);

        let bg_index = color_index(bg, step_array.len());
        let primary_container_bg = if let Some(primary_container_bg_color) = primary_container_bg {
            primary_container_bg_color
        } else {
            get_color(bg_index, 5, &step_array, is_dark, &p_ref.neutral_1)
        };

        let secondary_container_bg = if let Some(secondary_container_bg) = secondary_container_bg {
            secondary_container_bg
        } else {
            get_color(bg_index, 10, &step_array, is_dark, &p_ref.neutral_2)
        };

        let bg_component = get_color(bg_index, 8, &step_array, is_dark, &p_ref.neutral_2);
        let on_bg_component = get_text(
            color_index(bg_component, step_array.len()),
            &step_array,
            is_dark,
            &p_ref.neutral_8,
        );
        let bg_component = Component::component(
            bg_component,
            p_ref.neutral_0.to_owned(),
            p_ref.accent.to_owned(),
            on_bg_component,
            is_high_contrast,
        );

        let primary_index = color_index(primary_container_bg, step_array.len());
        let primary_component = get_color(primary_index, 6, &step_array, is_dark, &p_ref.neutral_3);
        let on_primary_component = get_text(
            color_index(primary_component, step_array.len()),
            &step_array,
            is_dark,
            &p_ref.neutral_8,
        );
        let primary_component = Component::component(
            primary_component,
            p_ref.neutral_0.to_owned(),
            p_ref.accent.to_owned(),
            on_primary_component,
            is_high_contrast,
        );

        let secondary_index = color_index(secondary_container_bg, step_array.len());
        let secondary_component =
            get_color(secondary_index, 3, &step_array, is_dark, &p_ref.neutral_4);
        let on_secondary_component = get_text(
            color_index(secondary_component, step_array.len()),
            &step_array,
            is_dark,
            &p_ref.neutral_10,
        );
        let secondary_component = Component::component(
            secondary_component,
            p_ref.neutral_0.to_owned(),
            p_ref.accent.to_owned(),
            on_secondary_component,
            is_high_contrast,
        );

        let mut theme: Theme<Srgba> = Theme {
            name: palette.name().to_string(),
            background: Container::new(
                bg_component,
                bg,
                get_text(bg_index, &step_array, is_dark, &p_ref.neutral_8),
            ),
            primary: Container::new(
                primary_component,
                primary_container_bg,
                get_text(primary_index, &step_array, is_dark, &p_ref.neutral_8),
            ),
            secondary: Container::new(
                secondary_component,
                secondary_container_bg,
                get_text(secondary_index, &step_array, is_dark, &p_ref.neutral_8),
            ),
            accent: Component::colored_component(
                p_ref.accent.to_owned(),
                p_ref.neutral_0.to_owned(),
                p_ref.accent.to_owned(),
            ),
            success: Component::colored_component(
                p_ref.green.to_owned(),
                p_ref.neutral_0.to_owned(),
                p_ref.accent.to_owned(),
            ),
            destructive: Component::colored_component(
                p_ref.red.to_owned(),
                p_ref.neutral_0.to_owned(),
                p_ref.accent.to_owned(),
            ),
            warning: Component::colored_component(
                p_ref.yellow.to_owned(),
                p_ref.neutral_0.to_owned(),
                p_ref.accent.to_owned(),
            ),
            palette: palette.inner(),
            spacing,
            corner_radii,
            is_dark,
            is_high_contrast,
        };
        theme.spacing = spacing;
        theme.corner_radii = corner_radii;
        theme
    }
}

fn get_index(base_index: usize, steps: usize, step_len: usize, is_dark: bool) -> Option<usize> {
    if is_dark {
        base_index.checked_add(steps)
    } else {
        base_index.checked_sub(steps)
    }
    .filter(|i| *i < step_len)
}

fn get_color(
    base_index: usize,
    steps: usize,
    step_array: &[Srgba; 100],
    is_dark: bool,
    fallback: &Srgba,
) -> Srgba {
    get_index(base_index, steps, step_array.len(), is_dark)
        .and_then(|i| step_array.get(i).cloned())
        .unwrap_or_else(|| fallback.to_owned())
}

fn get_text(
    base_index: usize,
    step_array: &[Srgba; 100],
    is_dark: bool,
    fallback: &Srgba,
) -> Srgba {
    let Some(index) = get_index(base_index, 70, step_array.len(), is_dark).or_else(|| get_index(base_index, 50, step_array.len(), is_dark)) else {
        return fallback.to_owned();
    };

    step_array
        .get(index)
        .cloned()
        .unwrap_or_else(|| fallback.to_owned())
}

fn color_index<C>(c: C, array_len: usize) -> usize
where
    Oklcha: FromColor<C>,
{
    let c = Oklcha::from_color(c);
    ((c.l * array_len as f32).round() as usize).clamp(0, array_len - 1)
}