Commonise floating-window logic (#41)

home-manager/nvim/build-utils.lua

@@ -0,0 +1,110 @@
+BuildUtils = {}
+
+-- Create a new buffer and a new floating window to hold that buffer.
+local function create_floating_window()
+	-- Create a new buffer for build output
+	local buf = vim.api.nvim_create_buf(false, true) -- No listed, scratch buffer
+
+	-- Calculate window size and position here (example: full width, 10 lines high at the bottom)
+	local width = vim.api.nvim_get_option_value("columns", {})
+	local height = vim.api.nvim_get_option_value("lines", {})
+	local win_height = math.min(10, math.floor(height * 0.2)) -- 20% of total height or 10 lines
+	local win_opts = {
+		relative = "editor",
+		width = width,
+		height = win_height,
+		col = 0,
+		row = height - win_height,
+		style = "minimal",
+		border = "single",
+	}
+
+	local win = vim.api.nvim_open_win(buf, false, win_opts)
+
+	return { window = win, buffer = buf }
+end
+
+local function _on_output(context, is_stdout, err, data, on_line)
+	local prefix
+	if is_stdout then
+		prefix = "OUT"
+	else
+		prefix = "ERR"
+	end
+	if err or data then
+		vim.schedule(function()
+			if err then
+				-- Append the error message to the buffer
+				local count = vim.api.nvim_buf_line_count(context.buffer)
+				vim.api.nvim_buf_set_lines(context.buffer, count, count, false, { "error " .. prefix .. ": " .. err })
+			end
+			if data then
+				-- Append the data to the buffer
+				local count = vim.api.nvim_buf_line_count(context.buffer)
+				vim.api.nvim_buf_set_lines(
+					context.buffer,
+					count,
+					count,
+					false,
+					vim.tbl_map(function(line)
+						return prefix .. ": " .. line
+					end, vim.split(data, "\n"))
+				)
+			end
+			if vim.api.nvim_win_is_valid(context.window) then
+				local cur_win = vim.api.nvim_get_current_win()
+				local cur_buf = vim.api.nvim_win_get_buf(cur_win)
+				if cur_buf ~= context.buffer then
+					local new_line_count = vim.api.nvim_buf_line_count(context.buffer)
+					vim.api.nvim_win_set_cursor(context.window, { new_line_count, 0 })
+				end
+			end
+
+			on_line(data, is_stdout, context)
+		end)
+	end
+end
+
+-- Arguments:
+-- * exe, a string (no need to escape this)
+-- * args, a table like { "-m", "venv", vim.fn.shellescape(some_path) }
+-- * description of this process, visible to the user, e.g. "venv creation"
+-- * context, the result of `create_floating_window`
+-- * on_line, a function which takes "the string written", (true if stdout else false), and the context table; should return nothing. We'll call that on every line of stdout and stderr.
+-- * on_complete, takes `context`, `code` (exit code) and `signal` ("documented" with neovim's uv.spawn, hah)
+local function run_external(exe, args, description, context, on_line, on_complete)
+	local handle
+	local stdout = vim.uv.new_pipe(false)
+	local stderr = vim.uv.new_pipe(false)
+	handle, _ = vim.uv.spawn(
+		exe,
+		{
+			args = args,
+			stdio = { nil, stdout, stderr },
+		},
+		vim.schedule_wrap(function(code, signal)
+			stdout:read_stop()
+			stderr:read_stop()
+			stdout:close()
+			stderr:close()
+			handle:close()
+			print("External process " .. description .. " completed, exit code " .. code .. " and signal " .. signal)
+			on_complete(context, code, signal)
+		end)
+	)
+
+	if not handle then
+		print("Failed to start " .. description .. " process.")
+		return
+	end
+
+	vim.uv.read_start(stdout, function(err, data)
+		_on_output(context, true, err, data, on_line)
+	end)
+	vim.uv.read_start(stderr, function(err, data)
+		_on_output(context, false, err, data, on_line)
+	end)
+end
+
+BuildUtils.create_window = create_floating_window
+BuildUtils.run = run_external