refactor(ui): share keymap spec helper between popup and stack view

Introduce ui/keymap_spec.lua as a thin helper that wraps
vim.keymap.set with the buffer/nowait/silent defaults the popup and
stack view keymaps both used. ui/keymaps.lua and ui/stack_view/keymaps.lua
now describe their bindings as PeekstackKeymapSpec lists and apply them
through the helper, removing duplicated registration boilerplate.

Author: mhiro2

lua/peekstack/ui/keymap_spec.lua

@@ -0,0 +1,72 @@
+local M = {}
+
+---@class PeekstackKeymapSpec
+---@field lhs string
+---@field rhs string|function
+---@field desc? string
+---@field mode? string|string[]
+---@field expr? boolean
+---@field nowait? boolean
+---@field silent? boolean
+---@field remap? boolean
+
+---@param spec PeekstackKeymapSpec
+---@param bufnr integer
+---@return table
+local function build_opts(spec, bufnr)
+  return {
+    buffer = bufnr,
+    nowait = spec.nowait ~= false,
+    silent = spec.silent ~= false,
+    desc = spec.desc,
+    expr = spec.expr,
+    remap = spec.remap,
+  }
+end
+
+---Set a single buffer-local keymap from a spec.
+---Skips empty/nil `lhs` entries so callers can pass user-configurable keys directly.
+---@param bufnr integer
+---@param spec PeekstackKeymapSpec
+function M.set(bufnr, spec)
+  if not spec.lhs or spec.lhs == "" then
+    return
+  end
+  vim.keymap.set(spec.mode or "n", spec.lhs, spec.rhs, build_opts(spec, bufnr))
+end
+
+---Apply multiple specs on a buffer.
+---@param bufnr integer
+---@param specs PeekstackKeymapSpec[]
+function M.apply(bufnr, specs)
+  for _, spec in ipairs(specs) do
+    M.set(bufnr, spec)
+  end
+end
+
+---Drop specs with empty `lhs` and de-dup by `lhs`, keeping the last occurrence.
+---Useful when user config produces overlapping shortcuts.
+---@param specs PeekstackKeymapSpec[]
+---@return PeekstackKeymapSpec[]
+function M.normalize(specs)
+  ---@type table<string, PeekstackKeymapSpec>
+  local by_lhs = {}
+  ---@type string[]
+  local order = {}
+  for _, spec in ipairs(specs) do
+    if spec.lhs and spec.lhs ~= "" then
+      if not by_lhs[spec.lhs] then
+        order[#order + 1] = spec.lhs
+      end
+      by_lhs[spec.lhs] = spec
+    end
+  end
+
+  local out = {}
+  for _, lhs in ipairs(order) do
+    out[#out + 1] = by_lhs[lhs]
+  end
+  return out
+end
+
+return M

lua/peekstack/ui/keymaps.lua

@@ -1,6 +1,7 @@
 local config = require("peekstack.config")
 local promote = require("peekstack.core.promote")
 local stack_view = require("peekstack.ui.stack_view")
+local keymap_spec = require("peekstack.ui.keymap_spec")
 
 local M = {}
 
@@ -16,17 +17,6 @@ local M = {}
 ---@type PeekstackSourcePopupMapState?
 local active_source_maps = nil
 
----@param bufnr integer
----@param lhs string?
----@param rhs string|function
----@param desc string
-local function map(bufnr, lhs, rhs, desc)
-  if not lhs or lhs == "" then
-    return
-  end
-  vim.keymap.set("n", lhs, rhs, { buffer = bufnr, nowait = true, silent = true, desc = desc })
-end
-
 --- Navigate from a popup to an adjacent split window.
 --- Moves focus back to the root (non-floating) window first, then executes
 --- wincmd in the given direction.
@@ -52,10 +42,10 @@ local function resolve_current_popup()
   return popup
 end
 
----@return { lhs: string, rhs: function, desc: string }[]
+---@return PeekstackKeymapSpec[]
 local function mapping_specs()
   local keys = config.get().ui.keys
-  ---@type { lhs: string, rhs: function, desc: string }[]
+  ---@type PeekstackKeymapSpec[]
   local raw = {
     {
       lhs = keys.close,
@@ -173,25 +163,7 @@ local function mapping_specs()
     },
   }
 
-  ---@type table<string, { lhs: string, rhs: function, desc: string }>
-  local by_lhs = {}
-  ---@type string[]
-  local order = {}
-  for _, spec in ipairs(raw) do
-    if spec.lhs and spec.lhs ~= "" then
-      if not by_lhs[spec.lhs] then
-        order[#order + 1] = spec.lhs
-      end
-      by_lhs[spec.lhs] = spec
-    end
-  end
-
-  ---@type { lhs: string, rhs: function, desc: string }[]
-  local specs = {}
-  for _, lhs in ipairs(order) do
-    specs[#specs + 1] = by_lhs[lhs]
-  end
-  return specs
+  return keymap_spec.normalize(raw)
 end
 
 ---@param bufnr integer
@@ -269,7 +241,7 @@ local function activate_source_popup(popup)
 
   for _, spec in ipairs(specs) do
     original[spec.lhs] = get_buffer_map(popup.bufnr, spec.lhs)
-    map(popup.bufnr, spec.lhs, spec.rhs, spec.desc)
+    keymap_spec.set(popup.bufnr, spec)
     lhs_list[#lhs_list + 1] = spec.lhs
   end
 
@@ -288,9 +260,7 @@ function M.apply_popup(popup)
     return
   end
 
-  for _, spec in ipairs(mapping_specs()) do
-    map(popup.bufnr, spec.lhs, spec.rhs, spec.desc)
-  end
+  keymap_spec.apply(popup.bufnr, mapping_specs())
 end
 
 ---@param target integer|PeekstackPopupModel