help: floating help box with dynamic keybinding content

lua/tiny-debugger/help.lua

@@ -0,0 +1,105 @@
+local config = require("tiny-debugger.config")
+
+local M = {}
+
+local win_id = nil
+local buf_id = nil
+
+local key_labels = {
+  continue = "Continue",
+  step_over = "Step over",
+  step_into = "Step into",
+  step_out = "Step out",
+  run_to_cursor = "Run to cursor",
+  breakpoint = "Toggle breakpoint",
+  cond_breakpoint = "Conditional breakpoint",
+  watch = "Watch expression",
+  hover = "Hover / inspect",
+  eval = "Eval in REPL",
+  terminate = "Quit debugging",
+  restart = "Restart session",
+  help = "Show this help",
+}
+
+-- ordered list of key names for consistent display
+local key_order = {
+  "continue", "step_over", "step_into", "step_out", "run_to_cursor",
+  "breakpoint", "cond_breakpoint", "watch", "hover", "eval",
+  "terminate", "restart", "help",
+}
+
+local function build_lines()
+  local lines = { " tiny-debugger keybindings", "" }
+  local keys = config.opts.keys
+  for _, name in ipairs(key_order) do
+    local key = keys[name]
+    if key then
+      local label = key_labels[name] or name
+      table.insert(lines, string.format("  %s  %s", key, label))
+    end
+  end
+  table.insert(lines, "")
+  return lines
+end
+
+local function calc_width(lines)
+  local max = 0
+  for _, line in ipairs(lines) do
+    max = math.max(max, #line)
+  end
+  return max + 2
+end
+
+function M.close()
+  if win_id and vim.api.nvim_win_is_valid(win_id) then
+    vim.api.nvim_win_close(win_id, true)
+  end
+  win_id = nil
+  if buf_id and vim.api.nvim_buf_is_valid(buf_id) then
+    vim.api.nvim_buf_delete(buf_id, { force = true })
+  end
+  buf_id = nil
+end
+
+function M.open()
+  M.close()
+
+  local lines = build_lines()
+  local width = calc_width(lines)
+  local height = #lines
+
+  buf_id = vim.api.nvim_create_buf(false, true)
+  vim.api.nvim_buf_set_lines(buf_id, 0, -1, false, lines)
+  vim.bo[buf_id].modifiable = false
+  vim.bo[buf_id].bufhidden = "wipe"
+
+  local editor_width = vim.o.columns
+  local editor_height = vim.o.lines
+
+  win_id = vim.api.nvim_open_win(buf_id, false, {
+    relative = "editor",
+    anchor = "SE",
+    row = editor_height - 2,
+    col = editor_width,
+    width = width,
+    height = height,
+    style = "minimal",
+    border = "rounded",
+    focusable = false,
+    noautocmd = true,
+  })
+
+  -- auto-close on next keypress
+  vim.api.nvim_create_autocmd({ "CursorMoved", "InsertEnter", "CmdlineEnter" }, {
+    once = true,
+    callback = function()
+      M.close()
+    end,
+  })
+end
+
+function M.is_open()
+  return win_id ~= nil and vim.api.nvim_win_is_valid(win_id)
+end
+
+return M

lua/tiny-debugger/mode.lua

@@ -1,4 +1,5 @@
 local config = require("tiny-debugger.config")
+local help = require("tiny-debugger.help")
 
 local M = {}
 
@@ -55,6 +56,7 @@ local function setup_default_actions()
     M.exit()
   end
   actions.restart = function() dap.restart() end
+  actions.help = function() help.open() end
 end
 
 local function set_keymaps(buf)
@@ -103,6 +105,10 @@ function M.enter()
   local buf = vim.api.nvim_get_current_buf()
   set_keymaps(buf)
   set_cursor_highlight()
+
+  if config.opts.help_on_enter then
+    help.open()
+  end
 end
 
 function M.exit()
@@ -112,6 +118,7 @@ function M.exit()
   local buf = vim.api.nvim_get_current_buf()
   clear_keymaps(buf)
   restore_cursor_highlight()
+  help.close()
 end
 
 function M.toggle()