#
# git handler for backupninja using gibak as backend
# feedback: rhatto at riseup.net
#
#  git handler is free software; you can redistribute it and/or modify it under the
#  terms of the GNU General Public License as published by the Free Software
#  Foundation; either version 2 of the License, or any later version.
#
#  git handler is distributed in the hope that it will be useful, but WITHOUT ANY
#  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
#  A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License along with
#  this program; if not, write to the Free Software Foundation, Inc., 59 Temple
#  Place - Suite 330, Boston, MA 02111-1307, USA
#
# Config file options
# -------------------
#
#   [general]
#   rm_older_than = set to the max history covered by git
#   fsck = set to "yes" to run 'git fsck' after commit
#   compress = set to "yes" to run 'git gc' after commit
#
#   [source]
#   repository = the git repository folder
#   pull = git repository list to pull changes from
#
#   [dest]
#   push = remote repositories to push changes after processing other tasks
#   send_patches = email recipients to send resulting patches
#
# Features
# --------
#
#   - Purge old revisions (to save space or remove sensitive data).
#   - Automatically add/remove files into revision control.
#   - Compression (gc) and checking (fsck).
#   - Pull changes from remote sources.
#   - Push branch to remote destinations.
#   - Send resulting patches to email recipients.
#
# TODO
# ----
#
#   - Issue warnings/errors at each failing stage.
#   - Merge operation.
#

function eval_config {

  setsection general
  getconf rm_older_than
  getconf fsck no
  getconf compress no

  setsection source
  getconf repository
  getconf pull

  setsection dest
  getconf push
  getconf send_patches

}

function run_gibak {

  local cmd="$*"

  if [ ! -d "$repository" ]; then
    fatal "Folder $repository does not exist."
    exit 1
  fi

  if [ ! -d "$repository/.git" ]; then
    $HOME=$repository gibak init
    cmd="commit"
  fi

  if [ -z "$cmd" ]; then
    cmd="commit"
  fi

  $HOME=$repository gibak $cmd

}

# Check configuration
eval_config

# Remove old content
if [ ! -z "$rm_older_than" ]; then
  run_gibak rm-older-than $rm_older_than
fi

# Commit changes
run_gibak $repository

# Pull changes from remote sources
if [ ! -z "$pull" ]; then
  cwd="`pwd`"
  cd $repository
  for remote in $pull; do
    git pull $remote
  done
  cd $pwd
fi

# Compress repository
if [ "$compress" == "yes" ]; then
  ( cd $repository && git gc )
fi

# Run fsck
if [ "$fsck" == "yes" ]; then
  ( cd $repository && git fsck )
fi

# Push changes to remote repositories
if [ ! -z "$push" ]; then
  cwd="`pwd`"
  cd $repository
  for remote in $push; do
    git push $remote master
  done
  cd $pwd
fi

# Send patches
if [ ! -z "$send_patches" ]; then
  cwd="`pwd`"
  cd $repository
  git format-patch origin
  git send-email --to $send_patches
  cd $pwd
fi