🌈

README.md

HOW TO 🌈

1. Save as 🌈.lua
2. cd $(dirname path/to/🌈.lua)
3. nvim 🌈.lua
4. :luafile %
5. Press F5 to 🌈

The F5 bit is just for demonstration. In an actual statusline, you'll want to uncomment line 65 so it actually checks for LSP messages.

🌈.lua

local config = {
	delay_ms = 100,
	frames = {
		"#bcbcbc",
		"#aaaaaa",
		"#989898",
		"#868686",
		"#757575",
		"#646464",
		"#545454",
		"#444444",
		"#353535",
		"#262626",
		"#353535",
		"#444444",
		"#545454",
		"#646464",
		"#757575",
		"#868686",
		"#989898",
		"#aaaaaa",
	},
}

-- HERE BE DRAGONS

local n_frames = #config.frames
-- Create highlight groups from frames
for i, fg in ipairs(config.frames) do
	vim.api.nvim_set_hl(0, 'rainbow' .. i, { fg=fg, bg="none" })
end
vim.api.nvim_set_hl(0, 'StatusLine', { fg="#bcbcbc", bg="none" })

-- Global state. Gotta make that buffer-local or something
--- Frame index
local i = 1
--- If this is true, the icon will start cycling through frames
local messages_available = false

--- Check for LSP messages
--@returns bool Are messages available for any client attached to this buffer?
local function has_messages(buf_id)
	for _, client in pairs(vim.lsp.buf_get_clients(buf_id)) do
		if not vim.tbl_isempty(client.messages.messages) then return true end
		for _, progress in pairs(client.messages.progress) do
			if not progress.done then return true end
		end
	end
	return false
end

local t = vim.loop.new_timer()

vim.api.nvim_create_augroup("rainbow_icon", {})
vim.api.nvim_create_autocmd("User", {
	pattern = "LspProgressUpdate",
	group = "rainbow_icon",
	desc = "Update rainbow",
	callback = function()
		local buf_id = vim.api.nvim_get_current_buf()
		if t:get_due_in() == 0 then
			t:start(config.delay_ms, config.delay_ms, function()
				-- This is just for demonstration. With a real LSP client,
				-- you'll want to uncomment this line:
				--messages_available = has_messages(buf_id)
				if messages_available then
					-- Cycle through colors
					i = i % n_frames + 1
					t:again()
				else
					-- Reset cycle index for next run
					i = 1
					t:stop()
				end
				-- Redraw statusline on next tick
				vim.schedule(function() vim.api.nvim_command("redrawstatus") end)
			end)
		end
	end,
})

function statusline()
	-- Icon
	local icon = "[I'M AN ICON!]"
	if messages_available then
		return '%#rainbow' .. i .. '#' .. icon .. '%#StatusLine# <- 🌈'
	else
		return '%#StatusLine#' .. icon .. ' Now press F5 to 🌈'
	end
end

vim.keymap.set('n',
	'<f5>',
	function()
		messages_available = not messages_available
		vim.cmd("doautocmd User LspProgressUpdate")
	end,
	{ buffer = true, desc = "Toggle rainbow" }
)
vim.o.statusline="%!v:lua.statusline()"