Add color theme config

* add option `theme` that allows for setting of a theme,
the default is `default`

* under `themes` the themes can be described as follows:

either:
```
themes:
  default:
    fg: [0,0,0]
    bg: [0,0,0]
    black: [0,0,0]
    red: [0,0,0]
    green: [0,0,0]
    yellow: [0,0,0]
    blue: [0,0,0]
    magenta: [0,0,0]
    cyan: [0,0,0]
    white: [0,0,0]
    orange: [0,0,0]
```
or
```
themes:
  default:
    fg: 0
    bg: 0
    black: 0
    red: 0
    green: 0
    yellow: 0
    blue: 0
    magenta: 0
    cyan: 0
    white: 0
    orange: 0
```

If the key is different from default, it needs to either be specified on
start with `options --theme [THEME]`, or in the configuration file under
theme: [THEME].

closes #390

9 files changed, 145 insertions, 20 deletions

diff --git a/zellij-client/src/lib.rs b/zellij-client/src/lib.rs
index 3817e7908..7ea4f81ee 100644
--- a/zellij-client/src/lib.rs
+++ b/zellij-client/src/lib.rs
@@ -91,7 +91,14 @@ pub fn start_client(
     let take_snapshot = "\u{1b}[?1049h";
     let bracketed_paste = "\u{1b}[?2004h";
     os_input.unset_raw_mode(0);
-    let palette = os_input.load_palette();
+    let config_options = Options::from_cli(&config.options, opts.command.clone());
+    let palette = config.themes.clone().map_or_else(
+        || os_input.load_palette(),
+        |t| {
+            t.theme_config(&config_options)
+                .unwrap_or_else(|| os_input.load_palette())
+        },
+    );
     let _ = os_input
         .get_stdout_writer()
         .write(take_snapshot.as_bytes())
@@ -102,8 +109,6 @@ pub fn start_client(
         .unwrap();
     std::env::set_var(&"ZELLIJ", "0");
 
-    let config_options = Options::from_cli(&config.options, opts.command.clone());
-
     let full_screen_ws = os_input.get_terminal_size_using_fd(0);
     let client_attributes = ClientAttributes {
         position_and_size: full_screen_ws,
diff --git a/zellij-server/src/lib.rs b/zellij-server/src/lib.rs
index b40362001..8f1ad73a5 100644
--- a/zellij-server/src/lib.rs
+++ b/zellij-server/src/lib.rs
@@ -15,7 +15,7 @@ use std::path::PathBuf;
 use std::sync::{Arc, Mutex, RwLock};
 use std::thread;
 use wasmer::Store;
-use zellij_tile::data::{Event, InputMode, PluginCapabilities};
+use zellij_tile::data::{Event, InputMode,Palette, PluginCapabilities};
 
 use crate::{
     os_input_output::ServerOsApi,
@@ -84,6 +84,7 @@ impl ErrorInstruction for ServerInstruction {
 pub(crate) struct SessionMetaData {
     pub senders: ThreadSenders,
     pub capabilities: PluginCapabilities,
+    pub palette: Palette,
     screen_thread: Option<thread::JoinHandle<()>>,
     pty_thread: Option<thread::JoinHandle<()>>,
     wasm_thread: Option<thread::JoinHandle<()>>,
@@ -400,6 +401,7 @@ fn init_session(
             to_server: None,
         },
         capabilities,
+        palette: client_attributes.palette,
         screen_thread: Some(screen_thread),
         pty_thread: Some(pty_thread),
         wasm_thread: Some(wasm_thread),
diff --git a/zellij-server/src/route.rs b/zellij-server/src/route.rs
index 8dcd98ffa..baac1e9c2 100644
--- a/zellij-server/src/route.rs
+++ b/zellij-server/src/route.rs
@@ -18,7 +18,7 @@ use zellij_utils::{
 fn route_action(
     action: Action,
     session: &SessionMetaData,
-    os_input: &dyn ServerOsApi,
+    _os_input: &dyn ServerOsApi,
     to_server: &SenderWithContext<ServerInstruction>,
 ) -> bool {
     let mut should_break = false;
@@ -34,7 +34,7 @@ fn route_action(
                 .unwrap();
         }
         Action::SwitchToMode(mode) => {
-            let palette = os_input.load_palette();
+            let palette = session.palette;
             // TODO: use the palette from the client and remove it from the server os api
             // this is left here as a stop gap measure until we shift some code around
             // to allow for this
diff --git a/zellij-tile/src/data.rs b/zellij-tile/src/data.rs
index cb4b2aa01..38b20dcdb 100644
--- a/zellij-tile/src/data.rs
+++ b/zellij-tile/src/data.rs
@@ -71,13 +71,13 @@ impl Default for InputMode {
 }
 
 #[derive(Clone, Copy, Debug, Serialize, Deserialize, PartialEq, Eq, Hash)]
-pub enum Theme {
+pub enum ThemeHue {
     Light,
     Dark,
 }
-impl Default for Theme {
-    fn default() -> Theme {
-        Theme::Dark
+impl Default for ThemeHue {
+    fn default() -> ThemeHue {
+        ThemeHue::Dark
     }
 }
 
@@ -105,7 +105,7 @@ impl Default for PaletteSource {
 #[derive(Clone, Copy, Debug, Serialize, Deserialize, PartialEq, Eq, Hash, Default)]
 pub struct Palette {
     pub source: PaletteSource,
-    pub theme: Theme,
+    pub theme_hue: ThemeHue,
     pub fg: PaletteColor,
     pub bg: PaletteColor,
     pub black: PaletteColor,
diff --git a/zellij-utils/src/input/config.rs b/zellij-utils/src/input/config.rs
index c4cf0cd72..56e333f46 100644
--- a/zellij-utils/src/input/config.rs
+++ b/zellij-utils/src/input/config.rs
@@ -7,6 +7,7 @@ use std::path::{Path, PathBuf};
 
 use super::keybinds::{Keybinds, KeybindsFromYaml};
 use super::options::Options;
+use super::theme::ThemesFromYaml;
 use crate::cli::{CliArgs, Command};
 use crate::setup;
 
@@ -23,6 +24,7 @@ pub struct ConfigFromYaml {
     #[serde(flatten)]
     pub options: Option<Options>,
     pub keybinds: Option<KeybindsFromYaml>,
+    pub themes: Option<ThemesFromYaml>,
 }
 
 /// Main configuration.
@@ -30,6 +32,7 @@ pub struct ConfigFromYaml {
 pub struct Config {
     pub keybinds: Keybinds,
     pub options: Options,
+    pub themes: Option<ThemesFromYaml>,
 }
 
 #[derive(Debug)]
@@ -48,7 +51,13 @@ impl Default for Config {
     fn default() -> Self {
         let keybinds = Keybinds::default();
         let options = Options::default();
-        Config { keybinds, options }
+        let themes = None;
+
+        Config {
+            keybinds,
+            options,
+            themes,
+        }
     }
 }
 
@@ -90,7 +99,13 @@ impl Config {
         let config_from_yaml: ConfigFromYaml = serde_yaml::from_str(&yaml_config)?;
         let keybinds = Keybinds::get_default_keybinds_with_config(config_from_yaml.keybinds);
         let options = Options::from_yaml(config_from_yaml.options);
-        Ok(Config { keybinds, options })
+        let themes = config_from_yaml.themes;
+
+        Ok(Config {
+            keybinds,
+            options,
+            themes,
+        })
     }
 
     /// Deserializes from given path.
diff --git a/zellij-utils/src/input/mod.rs b/zellij-utils/src/input/mod.rs
index 068e22bc4..93a1d2255 100644
--- a/zellij-utils/src/input/mod.rs
+++ b/zellij-utils/src/input/mod.rs
@@ -4,6 +4,7 @@ pub mod actions;
 pub mod config;
 pub mod keybinds;
 pub mod options;
+pub mod theme;
 
 use termion::input::TermRead;
 use zellij_tile::data::{InputMode, Key, ModeInfo, Palette, PluginCapabilities};
diff --git a/zellij-utils/src/input/options.rs b/zellij-utils/src/input/options.rs
index f9724c20f..c6c002b6d 100644
--- a/zellij-utils/src/input/options.rs
+++ b/zellij-utils/src/input/options.rs
@@ -11,6 +11,9 @@ pub struct Options {
     /// that is compatible with more fonts
     #[structopt(long)]
     pub simplified_ui: bool,
+    /// Set the default theme
+    #[structopt(long)]
+    pub theme: Option<String>,
 }
 
 impl Options {
@@ -32,7 +35,12 @@ impl Options {
             self.simplified_ui
         };
 
-        Options { simplified_ui }
+        let theme = None;
+
+        Options {
+            simplified_ui,
+            theme,
+        }
     }
 
     pub fn from_cli(&self, other: Option<Command>) -> Options {
diff --git a/zellij-utils/src/input/theme.rs b/zellij-utils/src/input/theme.rs
new file mode 100644
index 000000000..35bd3d87b
--- /dev/null
+++ b/zellij-utils/src/input/theme.rs
@@ -0,0 +1,94 @@
+use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
+
+use super::options::Options;
+use zellij_tile::data::{Palette, PaletteColor};
+
+/// Intermediate deserialization of themes
+#[derive(Debug, Clone, PartialEq, Deserialize, Serialize)]
+pub struct ThemesFromYaml(HashMap<String, Theme>);
+
+#[derive(Debug, Clone, PartialEq, Deserialize, Serialize)]
+struct Theme {
+    #[serde(flatten)]
+    palette: PaletteFromYaml,
+}
+
+/// Intermediate deserialization struct
+#[derive(Clone, Copy, Debug, Serialize, Deserialize, PartialEq, Eq, Hash, Default)]
+pub struct PaletteFromYaml {
+    pub fg: PaletteColorFromYaml,
+    pub bg: PaletteColorFromYaml,
+    pub black: PaletteColorFromYaml,
+    pub red: PaletteColorFromYaml,
+    pub green: PaletteColorFromYaml,
+    pub yellow: PaletteColorFromYaml,
+    pub blue: PaletteColorFromYaml,
+    pub magenta: PaletteColorFromYaml,
+    pub cyan: PaletteColorFromYaml,
+    pub white: PaletteColorFromYaml,
+    pub orange: PaletteColorFromYaml,
+}
+
+/// Intermediate deserialization enum
+// This is here in order to make the untagged enum work
+#[derive(Clone, Copy, Debug, Serialize, Deserialize, PartialEq, Eq, Hash)]
+#[serde(untagged)]
+pub enum PaletteColorFromYaml {
+    Rgb((u8, u8, u8)),
+    EightBit(u8),
+}
+
+impl Default for PaletteColorFromYaml {
+    fn default() -> Self {
+        PaletteColorFromYaml::EightBit(0)
+    }
+}
+
+impl ThemesFromYaml {
+    pub fn theme_config(self, opts: &Options) -> Option<Palette> {
+        let mut from_yaml = self;
+        match &opts.theme {
+            Some(theme) => from_yaml.from_default_theme(theme.to_owned()),
+            None => from_yaml.from_default_theme("default".into()),
+        }
+    }
+
+    fn get_theme(&mut self, theme: String) -> Option<Theme> {
+        self.0.remove(&theme)
+    }
+
+    fn from_default_theme(&mut self, theme: String) -> Option<Palette> {
+        self.clone()
+            .get_theme(theme)
+            .map(|t| Palette::from(t.palette))
+    }
+}
+
+impl From<PaletteFromYaml> for Palette {
+    fn from(yaml: PaletteFromYaml) -> Self {
+        Palette {
+            fg: yaml.fg.into(),
+            bg: yaml.fg.into(),
+            black: yaml.black.into(),
+            red: yaml.red.into(),
+            green: yaml.green.into(),
+            yellow: yaml.yellow.into(),
+            blue: yaml.blue.into(),
+            magenta: yaml.magenta.into(),
+            cyan: yaml.cyan.into(),
+            white: yaml.white.into(),
+            orange: yaml.orange.into(),
+            ..Palette::default()
+        }
+    }
+}
+
+impl From<PaletteColorFromYaml> for PaletteColor {
+    fn from(yaml: PaletteColorFromYaml) -> Self {
+        match yaml {
+            PaletteColorFromYaml::Rgb(color) => PaletteColor::Rgb(color),
+            PaletteColorFromYaml::EightBit(color) => PaletteColor::EightBit(color),
+        }
+    }
+}
diff --git a/zellij-utils/src/shared.rs b/zellij-utils/src/shared.rs
index bc8b67711..a741cc10b 100644
--- a/zellij-utils/src/shared.rs
+++ b/zellij-utils/src/shared.rs
@@ -8,7 +8,7 @@ use colors_transform::{Color, Rgb};
 use std::os::unix::fs::PermissionsExt;
 use std::path::Path;
 use std::{fs, io};
-use zellij_tile::data::{Palette, PaletteColor, PaletteSource, Theme};
+use zellij_tile::data::{Palette, PaletteColor, PaletteSource, ThemeHue};
 
 const UNIX_PERMISSIONS: u32 = 0o700;
 
@@ -64,7 +64,7 @@ pub fn _hex_to_rgb(hex: &str) -> (u8, u8, u8) {
 pub fn default_palette() -> Palette {
     Palette {
         source: PaletteSource::Default,
-        theme: Theme::Dark,
+        theme_hue: ThemeHue::Dark,
         fg: PaletteColor::EightBit(colors::BRIGHT_GRAY),
         bg: PaletteColor::EightBit(colors::GRAY),
         black: PaletteColor::EightBit(colors::BLACK),
@@ -80,7 +80,7 @@ pub fn default_palette() -> Palette {
 }
 
 // Dark magic
-pub fn _detect_theme(bg: PaletteColor) -> Theme {
+pub fn _detect_theme_hue(bg: PaletteColor) -> ThemeHue {
     match bg {
         PaletteColor::Rgb((r, g, b)) => {
             // HSP, P stands for perceived brightness
@@ -89,11 +89,11 @@ pub fn _detect_theme(bg: PaletteColor) -> Theme {
                 + 0.114 * (b as f64 * b as f64))
                 .sqrt();
             match hsp > 127.5 {
-                true => Theme::Light,
-                false => Theme::Dark,
+                true => ThemeHue::Light,
+                false => ThemeHue::Dark,
             }
         }
-        _ => Theme::Dark,
+        _ => ThemeHue::Dark,
     }
 }