nixvim: Add initial configuration for keymaps

Signed-off-by: George Kaklamanos <gkaklas@gkaklas.gr>

home-manager/nixvim/keymaps.nix

@@ -0,0 +1,50 @@
+{
+  pkgs,
+  config,
+  ...
+}: let
+  # Telescope
+  # { key = "<leader>ff";
+  #   action = config.nixvim.helpers.mkRaw "require('telescope.builtin').find_files";
+  # } becomes:
+  # { key = ldr "ff";
+  #   action = mfn "telescope.builtin" "find_files";
+  # } becomes:
+  # (tscope "ff" "find_files")
+  lua = config.nixvim.helpers.mkRaw;
+  ldr = k: "<leader>${k}";
+  key = k: fn: {
+    key = "${k}";
+    action = lua "${fn}";
+  };
+  lkey = k: fn: {
+    key = ldr "${k}";
+    action = lua "${fn}";
+  };
+  luaf = fn: "function() ${fn} end";
+  luafr = m: fn: "function() require('${m}').${fn} end";
+
+  mkey = module: k: fn: (lkey "${k}" "require('${module}').${fn}");
+  tscope = k: fn: mkey "telescope.builtin" "${k}" "${fn}";
+  gs = k: fn: mkey "gitsigns" "${k}" "${fn}";
+in {
+  programs.nixvim.keymaps = [
+    (tscope "ff" "find_files")
+    (tscope "fg" "live_grep")
+    (tscope "fb" "buffers")
+    (tscope "fh" "help_tags")
+
+    (gs "hs" "stage_hunk")
+    (gs "rs" "reset_hunk")
+    (gs "hS" "stage_buffer")
+    (gs "hu" "undo_stage_hunk")
+    (gs "hR" "reset_buffer")
+    (gs "hp" "preview_hunk")
+    (gs "tb" "toggle_current_line_blame")
+    (gs "hd" "diffthis")
+    (gs "td" "toggle_deleted")
+
+    (key "<F5>" (luafr "nvim-tree.api" "tree.toggle()"))
+    (lkey "d" "vim.cmd.bdelete")
+  ];
+}

home-manager/nixvim/nixvim.nix

@@ -3,6 +3,9 @@
   config,
   ...
 }: {
+  imports = [
+    ./keymaps.nix
+  ];
   programs.nixvim = {
     enable = true;
     plugins = {