feat: add 'auto' option to use vim.o.background for light/dark theme

fixes #63

Author: scottmckendry

README.md

@@ -113,7 +113,7 @@ require("cyberdream").setup({
     terminal_colors = true,
 
     theme = {
-        variant = "default", -- use "light" for the light variant
+        variant = "default", -- use "light" for the light variant. Also accepts "auto" to set dark or light colors based on the current value of `vim.o.background`
         highlights = {
             -- Highlight groups to override, adding new groups is also possible
             -- See `:h highlight-groups` for a list of highlight groups or run `:hi` to see all groups and their current values

lua/cyberdream/config.lua

@@ -1,7 +1,7 @@
 local M = {}
 
 ---@class ThemeConfig
----@field variant? string | "'default'" | "'light'"
+---@field variant? string | "'default'" | "'light'" | "'auto'"
 ---@field colors? table<string, string>
 ---@field highlights? table<string, table<string, string>>
 

lua/cyberdream/init.lua

@@ -18,4 +18,16 @@ vim.api.nvim_create_user_command("CyberdreamToggleMode", function()
     vim.api.nvim_exec_autocmds("User", { pattern = "CyberdreamToggleMode", data = new_variant })
 end, {})
 
+vim.api.nvim_create_autocmd("OptionSet", {
+    pattern = "background",
+    callback = function()
+        if vim.g.cyberdream_opts.theme.variant ~= "auto" then
+            return
+        end
+        local new_variant = vim.v.option_new == "dark" and "default" or "light"
+        util.toggle_lualine_theme(new_variant)
+        vim.api.nvim_exec_autocmds("User", { pattern = "CyberdreamToggleMode", data = new_variant })
+    end,
+})
+
 return M

lua/cyberdream/theme.lua

@@ -12,6 +12,12 @@ function M.setup()
         t = colors.light
     end
 
+    if opts.theme.variant == "auto" then
+        if vim.o.background == "light" then
+            t = colors.light
+        end
+    end
+
     -- Override colors with user defined colors
     t = vim.tbl_deep_extend("force", t, opts.theme.colors)