Added window handling functions

Added scratch buffer on startup
Attempt to wrangle windows so that at most only 3 are open via splitting
Project wide (file only) search
Properly layout "help" windows so they are at the bottom

config/nvim/init.lua

@@ -75,7 +75,99 @@ local function TrimBuffer()
 	vim.fn.winrestview(view)
 end
 
+local function MakeScratch()
+	local bufnr = vim.api.nvim_create_buf(true, true)
+
+	vim.api.nvim_buf_set_option(bufnr, "buftype",   "nofile")
+	vim.api.nvim_buf_set_option(bufnr, "bufhidden", "hide")
+	vim.api.nvim_buf_set_option(bufnr, "swapfile",  false)
+	vim.api.nvim_buf_set_option(bufnr, "modified",  false)
+
+	vim.api.nvim_buf_set_name(bufnr, "scratch")
+
+	vim.api.nvim_buf_set_text(bufnr, 0, 0, 0, -1, { "-*- Scratch Buffer -*-" })
+
+	-- @Hack: There isn't really any way to get the fullscreen size, 150 greater than the
+	-- half-screen width on all of my devices as we don't want to split in that case
+	if vim.o.columns > 150 then
+		vim.cmd(string.format("vsplit #%d", bufnr))
+		vim.cmd("wincmd p")
+	end
+end
+
+-- Windowing
+
+local _is_help = { help = true, man = true, qf = true }
+
+function ManageSplit()
+	local windows  = vim.api.nvim_tabpage_list_wins(0)
+	local bufnr    = vim.api.nvim_win_get_buf(windows[#windows])
+	local filetype = vim.bo[bufnr].filetype
+
+	local target_count = _is_help[filetype] and 3 or 2
+
+	if #windows == target_count then
+		-- We already have the target number of windows open so we should close our split window,
+		-- always close 2 because that is the right-most split. The third window if it exists is
+		-- the bottom most window and is a "help" window
+		vim.api.nvim_win_close(windows[2], false)
+	else
+		-- We have less than the required windows open so split the first window, we open the
+		-- "scratch" buffer in this new window, if it is still open. Otherwise the same buffer in
+		-- the first window is opened.
+		local scratch = vim.fn.bufnr("scratch")
+		local first   = vim.api.nvim_win_get_buf(windows[1])
+
+		bufnr = vim.api.nvim_buf_is_loaded(scratch) and scratch or first
+		vim.api.nvim_open_win(bufnr, true, { split = "right", win = windows[1] })
+	end
+end
+
+local function ProjectSearch()
+	local input = vim.fn.input("Search: ")
+
+	if input and input ~= "" then
+		vim.cmd("silent lgrep! \"" .. input .. "\" **")
+		vim.cmd("lopen | lfirst | wincmd p")
+	end
+end
+
+local function ExpandHelp(a)
+	local winid    = vim.api.nvim_get_current_win()
+	local filetype = vim.bo[vim.api.nvim_win_get_buf(winid)].filetype
+	local height   = a.event == "WinEnter" and math.floor(0.8 * vim.o.lines) or 5
+
+	if _is_help[filetype] then
+		vim.api.nvim_win_set_height(winid, height)
+	end
+end
+
+local function LayoutHelp(a)
+	if _is_help[vim.bo.filetype] then
+		local winid   = vim.api.nvim_get_current_win()
+		local windows = vim.api.nvim_tabpage_list_wins(0)
+
+		-- We need to close other "help" windows that may be open so search through the open
+		-- windows. There *should* only ever be 3 windows open if my window handling is working
+		-- correctly
+		for _, w in ipairs(windows) do
+			if w ~= winid then
+				local bufnr = vim.api.nvim_win_get_buf(w)
+				if _is_help[vim.bo[bufnr].filetype] then
+					vim.api.nvim_win_close(wi.winid, true)
+				end
+			end
+		end
+
+		-- Force the new window to the bottom and expand it to be 80% of the height
+		vim.cmd("wincmd J")
+		vim.cmd(string.format("resize %d", math.floor(0.8 * vim.o.lines)))
+	end
+end
+
+--------------------------------------------------------------------------------
 -- Input mappings
+--------------------------------------------------------------------------------
 
 vim.g.mapleader = " "
 
@@ -91,10 +183,18 @@ MAP("v", "K",         "{")
 MAP("n", "<Leader>k", ":Man<CR>")
 MAP("i", "<S-Tab>",   "<C-o><<")
 MAP("i", "<Tab>",     BufferComplete, { expr = true })
+MAP("n", "<Leader>s", ManageSplit)
+MAP("n", "<Leader>f", ProjectSearch)
 
+--------------------------------------------------------------------------------
 -- Autocommands
+--------------------------------------------------------------------------------
 
 AUTOCMD('BufEnter',    { command = "let b:man_default_sects=\"2,3\"", pattern = "*.c"      })
 AUTOCMD('BufReadPost', { command = "setlocal nornu",                  pattern = "quickfix" })
 
-AUTOCMD('BufWritePre', { callback = TrimBuffer, pattern = "*" })
+AUTOCMD('BufWritePre', { callback = TrimBuffer,  pattern = "*" })
+AUTOCMD('VimEnter',    { callback = MakeScratch, pattern = "*" })
+AUTOCMD('BufWinEnter', { callback = LayoutHelp,  pattern = "*" })
+AUTOCMD('WinEnter',    { callback = ExpandHelp,  pattern = "*" })
+AUTOCMD('WinLeave',    { callback = ExpandHelp,  pattern = "*" })