misc cleanup

home-manager/shared/programs/shell/git.nix

@@ -9,6 +9,12 @@
       };
       core.editor = "nvim";
       pull.rebase = true;
+      difftool."nvim_difftool" = {
+        cmd = ''nvim -c "packadd nvim.difftool" -c "DiffTool $LOCAL $REMOTE"'';
+      };
+      diff = {
+        tool = "nvim_difftool";
+      };
     };
     signing = {
       key = "cjriddz@protonmail.com";
@@ -50,6 +56,7 @@
         conflict-marker-style = "git";
         merge-editor = "vimdiff";
         diff-editor = "diffview";
+        diff-instructions = false;
         diff-formatter = ":git";
         movement = {
           edit = true;
@@ -97,6 +104,42 @@
           ''
         ];
       };
+      merge-tools.diffview-new = {
+        program = "sh";
+        edit-args = [
+          "-c"
+          ''
+            set -eux
+            nix run /home/e/dev/nvim.nix -- \
+            --server $NVIM \
+            --remote-send "<cmd>lua require('difftool').open('$left', '$right', {ignore = { '.git', '.jj' }})<cr>"
+            until nix run /home/e/dev/nvim.nix -- \
+                --headless \
+                --server "$NVIM" \
+                --remote-expr "v:lua.require'iofq.jj'.is_jj_diffedit_open()" 2>/dev/null | grep 0; do
+                sleep 1
+            done
+          ''
+        ];
+        diff-args = [
+          "-c"
+          ''
+            set -eu
+            rm -f "$right/JJ-INSTRUCTIONS"
+            git -C "$left" init -q
+            git -C "$left" add -A
+            git -C "$left" commit -q -m baseline --allow-empty
+            mv "$left/.git" "$right"
+            git -C "$right" add --intent-to-add -A
+            (cd "$right"; nvim -c "lua vim.g.snacks_indent=false" -c "lua require('lazy').load({plugins = {'diffview.nvim'}})" -c DiffviewOpen)
+            git -C "$right" diff-index --quiet --cached HEAD && { echo "No changes done, aborting split."; exit 1; }
+            git -C "$right" commit -q -m split
+            git -C "$right" restore . # undo changes in modified files
+            git -C "$right" reset .   # undo --intent-to-add
+            git -C "$right" clean -q -df # remove untracked files
+          ''
+        ];
+      };
       snapshot = {
         max-new-file-size = "10MiB";
       };