#!/bin/bash

# Use forgejo dump to make a backup of Forgejo
# Also restore from a previously made backup
# https://docs.gitea.io/en-us/backup-and-restore/

set -eu
set -o pipefail
IFS="$(printf '\n\t')"

PROGRAM="${0##*/}"
INSTALL_DIR=/usr/local/bin
TMP_DIR={{ forgejo_run_dir }}/tmp
WORK_DIR={{ forgejo_run_dir }}
DATA_DIR={{ forgejo_data_dir }}
LOG_DIR={{ forgejo_log_dir }}
REPO_DIR={{ forgejo_run_dir }}/forgejo-repositories/
CONFIG_FILE={{ forgejo_conf_dir }}/app.ini
DUMP_DIR={{ forgejo_run_dir }}/forgejo-dumps
MYSQL_USER={{ forgejo_db_user }}
MYSQL_DB={{ forgejo_db_name }}
MYSQL_PW={{ forgejo_db_pass }}

{% raw %}
if [ "$USER" != git ]; then
  echo "You must run this as user 'git'" && exit 1
fi

print_help() {
cat <<-_EOF

$PROGRAM

Usage:
  $PROGRAM {backup|restore <forgejo_dump_file>|prune <int>}

Commands:
  backup    Create a backup. Will save to $DUMP_DIR.
  restore   Restore a previously created backup, given on the command line:
            <forgejo_dump_file>, absolute path or relative to $PWD.
  prune     Remove previously dumped backups and keep <int> backups.

Options:
  -h        Print this help message and quit.
_EOF
}

do_backup() {
  echo "Backing up Forgejo..."
  mkdir -p "$DUMP_DIR"
  mkdir -p "$TMP_DIR"
  stop_service
  output_dump_file="$DUMP_DIR/forgejo-dump-$(date +'%Y%m%d').tar"
  mysql_dump_file="$DUMP_DIR/forgejo-db.sql"
  cd "$INSTALL_DIR" || exit 1
  ./forgejo dump -f "$output_dump_file" -c "$CONFIG_FILE" -t "$TMP_DIR" --skip-lfs-data -w "$WORK_DIR" --type tar
  mysqldump -u"$MYSQL_USER" -p"$MYSQL_PW" "$MYSQL_DB" > "$mysql_dump_file"
  restart_service
  cd "$DUMP_DIR" || exit 1
  tar --delete -f "$output_dump_file" forgejo-db.sql
  tar --append -f "$output_dump_file" "$(basename $mysql_dump_file)"
  rm "$mysql_dump_file"
  chmod 640 "$output_dump_file" # Make the file readable by group for scp to different host by different user
  gzip "$output_dump_file"
  echo "Done."
}

do_restore() {
  echo "Restoring Forgejo backup..."
  start_dir="$PWD"
  tar_file="$1"
  tar_dir="${tar_file%.tar.gz}" # Remove file extension
  chmod 600 "$tar_file" # Backup has changed permissions, restore them here
  echo "Extracting $tar_file..." && mkdir "$tar_dir" && tar xvzf "$tar_file" -C "$tar_dir" && echo "  OK."
  cd "$tar_dir" || exit 1
  rm app.ini
  echo -n "Restoring $DATA_DIR..." && rsync -avz --delete data/ "$DATA_DIR" && rm -rf data && echo "  OK."
  echo -n "Restoring $LOG_DIR..." && rsync -avz log/ "$LOG_DIR" && rm -rf log && echo "  OK."
  echo -n "Restoring $REPO_DIR..." && mkdir -p "$REPO_DIR" && rsync -avz --delete repos/ "$REPO_DIR" && rm -rf repos && echo "  OK."
  echo -n "Changing ownership..." && chown -R git:git "$CONFIG_FILE" "$WORK_DIR" && echo "  OK."
  echo -n "Restoring MySQL database..." && mysql --default-character-set=utf8mb4 -u"$MYSQL_USER" -p"$MYSQL_PW" "$MYSQL_DB" < forgejo-db.sql && rm forgejo-db.sql && echo "  OK."
  cd "$start_dir" || exit 1
  rmdir "$tar_dir"
  restart_service
  regenerate_hooks
  echo "Done."
}

do_prune() {
  echo "Pruning Forgejo backups and keeping $1 of them..."
  dumps=("$DUMP_DIR"/forgejo-dump-*.tar.gz)
  nb_of_dumps="${#dumps[@]}"
  nb_to_keep="$1"
  nb_to_prune=$((nb_of_dumps - nb_to_keep))
  if [ "$nb_to_prune" -gt "$nb_of_dumps" ]; then
    echo "There are only $nb_of_dumps backups, quitting." && exit 1
  fi
  if [ "$nb_to_prune" -le 0 ]; then
    echo "Nothing to do" && exit 1
  else
    for ((i=0; i < nb_to_prune; i++)); do
      echo -n "Removing ${dumps[$i]}..." && rm "${dumps[$i]}" && echo "  OK."
    done
  fi
}

cleanup() {
  rm "${DUMP_DIR}/forgejo-db.sql" 2>/dev/null && echo "Removed leftover database dump" || echo "No leftover database dump"
  rm "$DUMP_DIR"/forgejo-dump-*.tar 2>/dev/null && echo "Removed leftover backup archive" || echo "No leftover backup archive"
}

regenerate_hooks() {
  echo "Regenerating hooks..."
  cd "$INSTALL_DIR" || exit 1
  ./forgejo admin regenerate hooks --config "$CONFIG_FILE" && echo "Done."
}

stop_service() {
  echo -n "Stopping service..." && sudo systemctl stop forgejo.service && echo "  OK."
}

restart_service() {
  echo -n "Restarting service..." && sudo systemctl restart forgejo.service && echo "  OK."
}

[ "$#" = 0 ] || [ "$1" = '-h' ] && print_help && exit 1

if [ "$#" = 2 ]; then
  if [ "$1" = restore ]; then
    echo "STARTING restore"
    do_restore "$2"
    echo "DONE restore"
  elif [ "$1" = prune ]; then
    echo "STARTING prune"
    do_prune "$2"
    echo "DONE prune"
  else
    print_help && exit 1
  fi
elif [ "$#" = 1 ]; then
  if [ "$1" != backup ]; then
    print_help && exit 1
  fi
  echo "STARTING backup"
  cleanup
  do_backup
  echo "DONE backup"
else
  print_help && exit 1
fi

exit 0
{% endraw %}