fix: cursor position is cached

Running the toggle command via a keymap multiple times within the same
file was always returning the first toggled line rather than updating
the cursor position and using the next line.

lua/toggle-checkbox.lua

@@ -3,39 +3,38 @@ local checked_character = "x"
 local checked_checkbox = "[" .. checked_character .. "]"
 local unchecked_checkbox = "%[ %]"
 
-local bufnr = vim.api.nvim_buf_get_number(0)
-local cursor = vim.api.nvim_win_get_cursor(0)
-local current_line = vim.api.nvim_buf_get_lines(bufnr, cursor[1] - 1, cursor[1], false)[1] or ""
-
 local line_contains_an_unchecked_checkbox = function(line)
 	return string.find(line, unchecked_checkbox)
 end
 
-local write_line = function(new_line)
+local checkbox = {}
-	vim.api.nvim_buf_set_lines(bufnr, cursor[1] - 1, cursor[1], false, { new_line })
+
-	vim.api.nvim_win_set_cursor(0, cursor)
+checkbox.check = function(line)
+	return line:gsub("%[ %]", checked_checkbox)
+end
+
+checkbox.uncheck = function(line)
+	return line:gsub("%[" .. checked_character .. "%]", unchecked_checkbox)
 end
 
 local M = {}
 
-M.check = function()
-	local new_line = current_line:gsub("%[ %]", checked_checkbox)
-	write_line(new_line)
-end
-
 M.toggle = function()
+	local bufnr = vim.api.nvim_buf_get_number(0)
+	local cursor = vim.api.nvim_win_get_cursor(0)
+	local current_line = vim.api.nvim_buf_get_lines(bufnr, cursor[1] - 1, cursor[1], false)[1] or ""
+
 	-- If the line contains a checked checkbox then uncheck it.
 	-- Otherwise, if it contains an unchecked checkbox, check it.
+	local new_line = ""
 	if line_contains_an_unchecked_checkbox(current_line) then
-		M.check()
+		new_line = checkbox.check(current_line)
 	else
-		M.uncheck()
+		new_line = checkbox.uncheck(current_line)
 	end
-end
 
-M.uncheck = function()
+	vim.api.nvim_buf_set_lines(bufnr, cursor[1] - 1, cursor[1], false, { new_line })
-	local new_line = current_line:gsub("%[" .. checked_character .. "%]", unchecked_checkbox)
+	vim.api.nvim_win_set_cursor(0, cursor)
-	write_line(new_line)
 end
 
 return M