#!/bin/bash
# The MIT License (MIT)
# 
# Copyright (c) 2011-2016 Ismaël Bouya http://www.normalesup.org/~bouya/
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.


# Feel like tipping/donating? https://www.immae.eu/licenses_and_tipping

REMOTE=origin
REF_NS=auto_backup

function backup_refs() {
  pushd "$1" > /dev/null

  if git rev-parse --git-dir > /dev/null 2>&1; then
    git for-each-ref --format='%(refname)' refs/$REF_NS | while read ref; do
      git update-ref -d "$ref"
    done

    git for-each-ref --format='%(refname)' refs/heads refs/tags | while read ref; do
      new_ref=$(echo "$ref" | sed -e "s@^refs/@refs/$REF_NS/@")
      git update-ref $new_ref $ref
    done

    stash=0
    git reflog --pretty=tformat:'%H' refs/stash 2>/dev/null | while read ref; do
      git update-ref refs/$REF_NS/stash/stash_$stash $ref
      stash=$(($stash + 1))
    done

    export GIT_INDEX_FILE=`mktemp /tmp/git-backup-index.XXXXXX`
    git read-tree HEAD
    head_commit=$(git show-ref --hash --head ^HEAD)
    git add .
    COMMIT=`git commit-tree --no-gpg-sign $(git write-tree) -p $head_commit -m "Automatic backup"`
    git update-ref refs/$REF_NS/workdir $COMMIT
    rm -f "$GIT_INDEX_FILE"
    unset GIT_INDEX_FILE

    if git remote | grep -q "^$REMOTE$"; then
      git push --no-verify --no-signed -q --force $REMOTE "refs/$REF_NS/*:refs/$REF_NS/*"
      git for-each-ref --format='%(refname)' refs/$REF_NS | while read ref; do
        git update-ref -d "$ref"
      done
      # Pour récupérer: 
      # git fetch $REMOTE --force "refs/$REF_NS/*:refs/$REF_NS/*"
    fi
  fi

  popd > /dev/null
}

for directory in "$@"; do
  backup_refs $directory
done