From 96be21231bf8e19017dab118cc887a0f09b055f9 Mon Sep 17 00:00:00 2001
From: Bruno Raoult <braoult@gmail.com>
Date: Sat, 6 Jul 2024 19:27:22 +0200
Subject: [PATCH] improve git-split.sh (multiple splits, etc...)

---
 scripts/git-split.sh | 97 +++++++++++++++++++++++++++++++++++++-------
 1 file changed, 82 insertions(+), 15 deletions(-)

diff --git a/scripts/git-split.sh b/scripts/git-split.sh
index 5d593b7..de7f2a7 100755
--- a/scripts/git-split.sh
+++ b/scripts/git-split.sh
@@ -1,35 +1,102 @@
 #!/usr/bin/env bash
 #
-# Duplicate file, with history (well, sort of)
-#
-# Copy a git file, keeping history.
+# git-split.sh - duplicate GIT file, with history (well, sort of)
 # Sources:
 #   https://stackoverflow.com/a/53849613/3079831
 #   https://stackoverflow.com/a/75942970/3079831
+#
+# (C) Bruno Raoult ("br"), 2024
+# Licensed under the GNU General Public License v3.0 or later.
+# Some rights reserved. See COPYING.
+#
+# You should have received a copy of the GNU General Public License along with this
+# program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.html>.
+#
+# SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
 
 CMDNAME=${0##*/}                                  # script name
 
-if (( $# != 2 )); then
-   printf "Usage: %s original copy\n" "$CMDNAME"
+if (( $# == 0 || $# % 2 )); then
+   printf "Usage: %s orig1 copy [orig2 copy2 ...]\n" "$CMDNAME"
    exit 1
 fi
 
-from="$1"
-to="$2"
+yes_or_no() {
+    while true; do
+        read -rp "$* [y/N]: " yn
+        case $yn in
+            [Yy])
+                return 0
+                ;;
+            [Nn]|"")
+                printf "Aborted.\n"
+                return  1
+                ;;
+        esac
+    done
+    # not reached
+}
+
+# prints out and run a command.
+echorun () {
+    printf ">>> %s\n" "$*"
+    "$@"
+    return $?
+}
+
+declare -A files
+declare -a from                                   # to keep order
+
+while (($#)); do
+    if [[ ! -f "$1" ]]; then
+        printf "Missing '%s'. Aborting.\n" "$1"
+        exit 1
+    elif [[ -f "$2" ]]; then
+        printf "'%s' already exists. Aborting.\n" "$2"
+        exit 1
+    fi
+    files["$1"]="$2"
+    from+=("$1")
+    shift 2
+done
+
+printf "The following files will be split :\n"
+
+for file in "${from[@]}"; do
+    printf "%s -> %s\n" "$file" "${files[$file]}"
+done
+
+yes_or_no "Proceed (y/N)? " || exit 1
+
 branch="split-file"
 
-printf "Dup from=[%s] to=[%s] branch=[%s]\n" "$from" "$to" "$branch"
+printf -v msg1 "Splitting '%s'" "${from[0]}"
+printf -v msg2 "Restore duplicated %s" "${from[0]}"
+if (( ${#from[@]} > 1 )); then
+    msg1+=" and $(( ${#from[@]} - 1 )) others"
+    msg2+=" and $(( ${#from[@]} - 1 )) others"
 
-git checkout -b "$branch"                         # create and switch to branch
+fi
+printf "%s using  branch '$branch'.\n" "$msg1"
 
-git mv "$from" "$to"                              # make the duplicate
-git commit -m "Duplicate $from to $to"
+if git show-ref --verify --quiet "refs/heads/$branch"; then
+    echorun git switch "$branch"
+    echorun git merge master
+else
+    echorun git switch -c "$branch"
+fi
 
-git checkout HEAD~ "$from"                        # bring back the original
-git commit -m "Restore duplicated $from"
+for file in "${from[@]}"; do                      # make the duplicates
+    echorun git mv "$file" "${files[$file]}"
+done
+echorun git commit -m "$msg1"                     # ... and commit
 
-git checkout -                                    # switch back to source branch
-git merge --no-ff "$branch" -m "Merge $branch"    # merge dup into source branch
+for file in "${from[@]}"; do                      # bring back the original
+    echorun git checkout HEAD~ "$file"
+done
+echorun git commit -m "$msg2"                     # ... and commit
 
+echorun git checkout -                                 # switch back to source branch
+echorun git merge --no-ff "$branch" -m "Merge $branch" # merge dup into source branch
 
 exit 0