config: default options table with deep merge

lua/tiny-debugger/config.lua

@@ -1,5 +1,71 @@
 local M = {}
 
-M.defaults = {}
+M.defaults = {
+  help_on_enter = true,
+  builtin_adapters = true,
+
+  keys = {
+    continue = "c",
+    step_over = "s",
+    step_into = "d",
+    step_out = "r",
+    run_to_cursor = "C",
+    breakpoint = "x",
+    cond_breakpoint = "X",
+    watch = "W",
+    hover = "K",
+    eval = "E",
+    terminate = "q",
+    restart = "R",
+    help = "?",
+  },
+
+  dapui = {
+    controls = { enabled = false },
+    layouts = {
+      {
+        position = "right",
+        size = 40,
+        elements = {
+          { id = "scopes", size = 0.50 },
+          { id = "watches", size = 0.25 },
+          { id = "stacks", size = 0.25 },
+        },
+      },
+      {
+        position = "bottom",
+        size = 12,
+        elements = {
+          { id = "repl", size = 0.50 },
+          { id = "console", size = 0.50 },
+        },
+      },
+    },
+  },
+
+  virtual_text = {
+    commented = true,
+    highlight_changed_variables = true,
+    only_first_definition = false,
+    all_frames = false,
+  },
+
+  adapters = {},
+}
+
+M.opts = vim.deepcopy(M.defaults)
+
+function M.merge(user_opts)
+  M.opts = vim.tbl_deep_extend("force", vim.deepcopy(M.defaults), user_opts or {})
+  -- preserve false values for disabled keys (tbl_deep_extend drops them)
+  if user_opts and user_opts.keys then
+    for k, v in pairs(user_opts.keys) do
+      if v == false then
+        M.opts.keys[k] = false
+      end
+    end
+  end
+  return M.opts
+end
 
 return M