Implement automatic light/dark mode switching for Ghostty, Neovim, and Zellij with Tokyo Night and GitHub themes

.bashrc

@@ -28,6 +28,13 @@ shopt -s nocaseglob
 # ghostty
 if [[ -n ${GHOSTTY_RESOURCES_DIR} ]]; then
   builtin source "${GHOSTTY_RESOURCES_DIR}/shell-integration/bash/ghostty.bash"
+
+  # Auto-switch Ghostty theme based on time of day
+  if [[ -x "${HOME}/.dotfiles/bin/set-ghostty-theme" ]]; then
+    "${HOME}/.dotfiles/bin/set-ghostty-theme" 2>/dev/null || true
+  elif [[ -x "$(dirname "${BASH_SOURCE[0]}")/bin/set-ghostty-theme" ]]; then
+    "$(dirname "${BASH_SOURCE[0]}")/bin/set-ghostty-theme" 2>/dev/null || true
+  fi
 fi
 
 # starship
@@ -144,6 +151,13 @@ fi
 
 # Auto start|attach zellij session
 if command -v zellij &>/dev/null; then
+  # Auto-switch Zellij theme based on time of day
+  if [[ -x "${HOME}/.dotfiles/bin/set-zellij-theme" ]]; then
+    "${HOME}/.dotfiles/bin/set-zellij-theme" 2>/dev/null || true
+  elif [[ -x "$(dirname "${BASH_SOURCE[0]}")/bin/set-zellij-theme" ]]; then
+    "$(dirname "${BASH_SOURCE[0]}")/bin/set-zellij-theme" 2>/dev/null || true
+  fi
+
   if [ -z "$ZELLIJ" ]; then
     zellij attach -c 'BDS 🐑'
   fi

.config/ghostty/config

@@ -1,2 +1,2 @@
-theme = "dracula"
+theme = "GitHub-Light-High-Contrast"
 window-padding-x = 2,4

.config/nvim/lua/config/autocmds.lua

@@ -110,3 +110,63 @@ autocmd("FileType", {
   end,
   desc = "Disable backups for crontab editing",
 })
+
+-- ===================================================================
+-- TIME-BASED THEME SWITCHING
+-- ===================================================================
+
+-- Auto-switch colorscheme based on time of day
+local function switch_theme_by_time()
+  -- Function to get time-based colorscheme
+  local function get_time_based_colorscheme()
+    -- Try to use our theme-mode script if available
+    local theme_mode_paths = {
+      vim.fn.expand("~/.dotfiles/bin/theme-mode"),
+      vim.fn.expand("~/.config/nvim/../../bin/theme-mode"),
+    }
+
+    for _, path in ipairs(theme_mode_paths) do
+      if vim.fn.executable(path) == 1 then
+        local handle = io.popen(path .. " 2>/dev/null")
+        if handle then
+          local mode = handle:read("*a"):gsub("%s+", "")
+          handle:close()
+
+          if mode == "light" then
+            return "tokyonight-day"
+          else
+            return "tokyonight-night"
+          end
+        end
+      end
+    end
+
+    -- Fallback: use system time directly
+    local hour = tonumber(os.date("%H"))
+    if hour >= 7 and hour < 19 then
+      return "tokyonight-day"
+    else
+      return "tokyonight-night"
+    end
+  end
+
+  local new_colorscheme = get_time_based_colorscheme()
+  if vim.g.colors_name ~= new_colorscheme then
+    vim.cmd.colorscheme(new_colorscheme)
+  end
+end
+
+-- Create augroup for theme switching
+local themeGroup = augroup("TimeBasedTheme", { clear = true })
+
+-- Switch theme on entering Neovim
+autocmd("VimEnter", {
+  group = themeGroup,
+  callback = switch_theme_by_time,
+  desc = "Switch colorscheme based on time when entering Neovim",
+})
+
+-- Optionally switch theme periodically (every 30 minutes)
+-- Uncomment the following to enable periodic theme switching:
+-- local theme_timer = vim.loop.new_timer()
+-- theme_timer:start(0, 30 * 60 * 1000, vim.schedule_wrap(switch_theme_by_time))

.config/nvim/lua/config/lazy.lua

@@ -45,7 +45,7 @@ require("lazy").setup({
     version = false, -- always use the latest git commit
     -- version = "*", -- try installing the latest stable version for plugins that support semver
   },
-  install = { colorscheme = { "dracula", "tokyonight", "habamax" } },
+  install = { colorscheme = { "tokyonight-night", "tokyonight-day", "tokyonight", "habamax" } },
   checker = { enabled = true }, -- automatically check for plugin updates
   performance = {
     rtp = {

.config/nvim/lua/plugins/colorscheme.lua

@@ -1,26 +1,86 @@
--- Dracula colorscheme configuration
+-- Colorscheme configuration with automatic light/dark switching
 return {
+  -- Tokyo Night colorscheme (both light and dark modes)
   {
-    "Mofiqul/dracula.nvim",
-    lazy = false, -- Load immediately (colorscheme should be available early)
-    priority = 1000, -- High priority to load before other plugins
+    "folke/tokyonight.nvim",
+    lazy = false,
+    priority = 1000,
     config = function()
-      require("dracula").setup({
-        -- Dracula theme customization
-        colors = {}, -- Use default dracula colors
-        show_end_of_buffer = true, -- Show '~' characters after buffer end
-        transparent_bg = false, -- Use dracula background color
-        lualine_bg_color = "#44475a", -- Custom lualine background
-        italic_comment = true, -- Italicize comments
+      require("tokyonight").setup({
+        style = "night", -- The theme comes in three styles, `storm`, `moon`, a darker variant `night` and `day`
+        light_style = "day", -- The theme is used when the background is set to light
+        transparent = false, -- Enable this to disable setting the background color
+        terminal_colors = true, -- Configure the colors used when opening a `:terminal` in Neovim
+        styles = {
+          comments = { italic = true },
+          keywords = { italic = true },
+          functions = {},
+          variables = {},
+          -- Background styles. Can be "dark", "transparent" or "normal"
+          sidebars = "dark", -- style for sidebars, see below
+          floats = "dark", -- style for floating windows
+        },
+        sidebars = { "qf", "help" }, -- Set a darker background on sidebar-like windows
+        day_brightness = 0.3, -- Adjusts the brightness of the colors of the **Day** style. Number between 0 and 1, from dull to vibrant colors
+        hide_inactive_statusline = false, -- Enabling this option, will hide inactive statuslines and replace them with a thin border instead
+        dim_inactive = false, -- dims inactive windows
+        lualine_bold = false, -- When `true`, section headers in the lualine theme will be bold
       })
     end,
   },
 
-  -- Configure LazyVim to use dracula as default colorscheme
+  -- Configure LazyVim with automatic theme detection
   {
     "LazyVim/LazyVim",
-    opts = {
-      colorscheme = "dracula",
-    },
+    opts = function()
+      -- Function to detect and set theme based on time
+      local function get_time_based_colorscheme()
+        -- Try to use our theme-mode script if available
+        local theme_mode_paths = {
+          vim.fn.expand("~/.dotfiles/bin/theme-mode"),
+          vim.fn.expand("~/.config/nvim/../../bin/theme-mode"),
+        }
+
+        for _, path in ipairs(theme_mode_paths) do
+          if vim.fn.executable(path) == 1 then
+            local handle = io.popen(path .. " nvim-light 2>/dev/null")
+            if handle then
+              local light_theme = handle:read("*a"):gsub("%s+", "")
+              handle:close()
+
+              handle = io.popen(path .. " nvim-dark 2>/dev/null")
+              if handle then
+                local dark_theme = handle:read("*a"):gsub("%s+", "")
+                handle:close()
+
+                handle = io.popen(path .. " 2>/dev/null")
+                if handle then
+                  local mode = handle:read("*a"):gsub("%s+", "")
+                  handle:close()
+
+                  if mode == "light" then
+                    return "tokyonight-day"
+                  else
+                    return "tokyonight-night"
+                  end
+                end
+              end
+            end
+          end
+        end
+
+        -- Fallback: use system time directly
+        local hour = tonumber(os.date("%H"))
+        if hour >= 7 and hour < 19 then
+          return "tokyonight-day"
+        else
+          return "tokyonight-night"
+        end
+      end
+
+      return {
+        colorscheme = get_time_based_colorscheme(),
+      }
+    end,
   },
 }

.config/zellij/config.kdl

@@ -60,5 +60,5 @@ keybinds {
 }
 
 pane_frames false
-theme "dracula"
+theme "default"
 mouse_mode true

README.md

@@ -64,3 +64,51 @@ A few other notes:
 * Ensure that `~/.bash_login` does not exist.
 
 See also https://www.gnu.org/software/bash/manual/html_node/Bash-Startup-Files.html
+
+## Automatic Light/Dark Mode Switching
+
+This dotfiles setup includes automatic light/dark mode switching for both Ghostty terminal and Neovim based on the time of day.
+
+### How it works
+
+- **Light Mode**: Active from 7:00 AM to 6:59 PM
+- **Dark Mode**: Active from 7:00 PM to 6:59 AM
+- **Ghostty**: Switches between `github-light` and `dracula` themes
+- **Neovim**: Switches between `github_light_high_contrast` and `github_dark_high_contrast` colorschemes
+
+### Components
+
+1. **`bin/theme-mode`**: Core script that detects current time and returns appropriate theme
+2. **`bin/set-ghostty-theme`**: Updates Ghostty configuration with time-appropriate theme
+3. **Bash Integration**: Automatically runs theme switching on new shell launches
+4. **Neovim Integration**: Automatically sets colorscheme when Neovim starts
+
+### Manual Theme Control
+
+You can manually test or force theme changes:
+
+```bash
+# Check current theme mode
+~/.dotfiles/bin/theme-mode
+
+# Manually switch Ghostty theme
+~/.dotfiles/bin/set-ghostty-theme
+
+# Get theme names for different tools
+~/.dotfiles/bin/theme-mode ghostty-light    # Returns: github-light
+~/.dotfiles/bin/theme-mode ghostty-dark     # Returns: dracula
+~/.dotfiles/bin/theme-mode nvim-light       # Returns: github_light_high_contrast  
+~/.dotfiles/bin/theme-mode nvim-dark        # Returns: dracula
+```
+
+### Requirements
+
+- **Ghostty**: Must have `github-light` and `dracula` themes available
+- **Neovim**: Requires the github-nvim-theme plugin (installed automatically via LazyVim)
+- **Portability**: Works on Linux and macOS systems
+
+The switching happens automatically on:
+- New terminal/shell sessions (Ghostty)  
+- Neovim startup (colorscheme selection)
+
+For troubleshooting, check that the scripts in `bin/` are executable and that your system's `date` command works correctly.

bin/set-ghostty-theme

@@ -0,0 +1,72 @@
+#!/usr/bin/env bash
+#
+# set-ghostty-theme - Set Ghostty theme based on current time
+#
+# This script updates the Ghostty configuration to use light or dark theme
+# based on the current hour of the day.
+#
+
+set -euo pipefail
+
+# Get the directory where this script lives to find theme-mode
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+THEME_MODE_SCRIPT="${SCRIPT_DIR}/theme-mode"
+
+# Configuration file path - check both the dotfiles repo and installed location
+DOTFILES_GHOSTTY_CONFIG="$(dirname "$SCRIPT_DIR")/.config/ghostty/config"
+HOME_GHOSTTY_CONFIG="${HOME}/.config/ghostty/config"
+
+# Use the dotfiles repo config if it exists, otherwise use the home config
+if [[ -f "$DOTFILES_GHOSTTY_CONFIG" ]]; then
+  GHOSTTY_CONFIG="$DOTFILES_GHOSTTY_CONFIG"
+else
+  GHOSTTY_CONFIG="$HOME_GHOSTTY_CONFIG"
+fi
+
+# Ensure the theme-mode script exists
+if [[ ! -x "$THEME_MODE_SCRIPT" ]]; then
+  echo "Error: theme-mode script not found or not executable at $THEME_MODE_SCRIPT" >&2
+  exit 1
+fi
+
+# Get current theme mode and corresponding Ghostty theme
+MODE=$("$THEME_MODE_SCRIPT")
+case "$MODE" in
+  "light")
+    THEME=$("$THEME_MODE_SCRIPT" ghostty-light)
+    ;;
+  "dark")
+    THEME=$("$THEME_MODE_SCRIPT" ghostty-dark)
+    ;;
+  *)
+    echo "Error: Unknown theme mode: $MODE" >&2
+    exit 1
+    ;;
+esac
+
+# Update or create the Ghostty config file
+if [[ -f "$GHOSTTY_CONFIG" ]]; then
+  # Create a temporary file to ensure atomic update
+  TEMP_CONFIG=$(mktemp)
+
+  if grep -q "^theme = " "$GHOSTTY_CONFIG"; then
+    # Replace existing theme line, preserving other lines
+    sed "s/^theme = .*/theme = \"$THEME\"/" "$GHOSTTY_CONFIG" > "$TEMP_CONFIG"
+  else
+    # Append theme line if not found
+    cp "$GHOSTTY_CONFIG" "$TEMP_CONFIG"
+    echo "theme = \"$THEME\"" >> "$TEMP_CONFIG"
+  fi
+
+  # Replace original with updated version
+  mv "$TEMP_CONFIG" "$GHOSTTY_CONFIG"
+else
+  # Create config file with theme
+  mkdir -p "$(dirname "$GHOSTTY_CONFIG")"
+  echo "theme = \"$THEME\"" > "$GHOSTTY_CONFIG"
+fi
+
+# Optional: print what we did (useful for debugging)
+if [[ "${VERBOSE:-}" == "1" ]]; then
+  echo "Set Ghostty theme to '$THEME' (mode: $MODE)"
+fi