#!/bin/sh

set -x
set -e
set -u

[ -n "${DEBEMAIL:-}" ] || DEBEMAIL="jenkins.grml.org Autobuilder <jenkins@grml.org>"
export DEBEMAIL

if [ ! -d source ] ; then
  echo "Please run the script in the jenkins workspace." >&2
  exit 1
fi

if [ -z "${BUILD_NUMBER:-}" ] ; then
  echo "No BUILD_NUMBER defined, please run it in jenkins." >&2
  exit 1
fi

if [ -z "${GIT_COMMIT:-}" ] ; then
  echo "No GIT_COMMIT defined, please run it with git-plugin in jenkins. ">&2
  exit 1
fi

# we want to get a version string like
# $ORIG_VERSION+0~$TIMESTAMP.$BUILD_NUMBER~1.$GIT_ID
# so the version is always increasing over time, no matter what
TIMESTAMP="$(date +%s)" # seconds since 1970-01-01 00:00:00 UTC, reversible via `date -d @$TIMESTAMP`
BUILD_VERSION="${TIMESTAMP}.${BUILD_NUMBER}" # git-dch appends something like ~1.gbp5f433e then

echo "***  source package build phase ***"
rm -f ./* || true

cd source

# version number
ORIG_VERSION=$(dpkg-parsechangelog --count 1 | awk '/Version/ {print $2}')

# we do NOT raise the version number, if we detect an unreleased version
DISTRIBUTION=$(dpkg-parsechangelog --count 1 | awk '/^Distribution/ {print $2}')
if [ "$DISTRIBUTION" = "UNRELEASED" ] ; then
  echo "*** Not increasing version number as distribution is set to UNRELEASED ***"
  INCREASED_VERSION="$ORIG_VERSION"
else
  INCREASED_VERSION=$(increase-version-number $ORIG_VERSION)
fi

VERSION_STRING="${INCREASED_VERSION}~${BUILD_VERSION}"

if [ -n "${distribution:-}" ] ; then
  echo "Distribution variable found. Adding distribution specific version."
  VERSION_STRING="${VERSION_STRING}+${distribution}"
fi

# support overriding git-dch options
if [ -n "${DCH_OPTS:-}" ] ; then
  echo "Found environment variable DCH_OPTS, set to ${DCH_OPTS}"
else
  DCH_OPTS="-S --multimaint-merge --ignore-branch"
  echo "Using default git-dch options (${DCH_OPTS})"
fi

# support overriding extra options for git-dch
if [ -n "${DCH_EXTRA_OPTS:-}" ] ; then
  echo "Found environment variable DCH_EXTRA_OPTS, set to ${DCH_EXTRA_OPTS}"
else
  DCH_EXTRA_OPTS="--new-version=${VERSION_STRING}"
  echo "Using extra git-dch options (${DCH_EXTRA_OPTS})"
fi

create_local_branch() {
  [ -n "${1:-}" ] || return 1

  local BRANCH="$1"

  if git branch -a | grep -q "remotes/origin/${BRANCH}" ; then
    git branch -D "${BRANCH}" || true
    git branch "${BRANCH}" "remotes/origin/${BRANCH}"
  else
    echo "NOTE: branch $BRANCH does not exist, ignoring request to checkout therefore."
  fi
}

identify_latest_change() {
  # debian/changelog might be a symlink (e.g. because debian points to
  # pkg/debian), so make sure we don't access a non-existing file
  git checkout -- $(readlink -f debian/changelog)
  local OLD_VERSION=$(dpkg-parsechangelog | awk '/^Version: / {print $2}')

  local tag=$(git describe $(git rev-list --tags='[^ju]*' --max-count=1 HEAD))
  local last_merge=$(git describe $(git rev-list --all --merges --max-count=1 HEAD))
  local since=${tag}

  if [ -n "$last_merge" ] ; then
    local m_date=$(git log ${last_merge} --pretty="format:%at" -1)
    local t_date=$(git log ${tag} --pretty="format:%at" -1)
    if [ ${m_date} -gt ${t_date} ] ; then
      local since=${last_merge}
    fi
  fi

  echo "Last tag / merge seems to be $since"
  git-dch -s "${since}" $DCH_OPTS $DCH_EXTRA_OPTS

  local NEW_VERSION=$(dpkg-parsechangelog | awk '/^Version: / {print $2}')

  if dpkg --compare-versions "$NEW_VERSION" lt "$OLD_VERSION" ; then
    echo "Calculated version is older than last release, falling back to auto mode."
    # debian/changelog might be a symlink (e.g. because debian points to
    # pkg/debian), so make sure we don't access a non-existing file
    git checkout -- $(readlink -f debian/changelog)
    git-dch --auto $DCH_OPTS $DCH_EXTRA_OPTS
  fi
}

git_dch_auto() {
  git-dch --auto $DCH_OPTS $DCH_EXTRA_OPTS
}

git_tag_build() {
  git checkout "${tag}"

  if [ -n "${distribution:-}" ] ; then
    echo "Distribution found. Adding distribution specific version (${distribution})."
    dch -b -v "${VERSION_STRING}+${distribution:-}" \
      "Tagged autobuild for ${distribution} via jenkins-debian-glue."
  else
    dch -v "${VERSION_STRING}" \
      "Tagged autobuild via jenkins-debian-glue."
  fi
}

# Clean up any unexpected local changes
#git reset --hard HEAD

# make sure common branches are available for git-buildpackage
create_local_branch upstream
create_local_branch debian
create_local_branch pristine-tar

# Drop residual files
#git clean -xfd

if [ -n "${branch:-}" ] ; then
  echo "Branch parameter set, checking out $branch"
  git checkout "${branch}"
else
  echo "No branch parameter set, checking out $GIT_COMMIT"
  git checkout "$GIT_COMMIT"
fi

if [ -n "${tag:-}" ] ; then
  echo "Tag parameter found, using dch for changelog generation."
  git_tag_build
elif [ "${1:-}" = "auto" ] ; then
  echo "Using git-dch with auto mode."
  git_dch_auto
elif [ -r debian/gbp.conf ] ; then
  echo "Found debian/gbp.conf, using git-dch with auto mode."
  git_dch_auto
else
  echo "Trying to identify latest tag / merge..."

  if ! git describe $(git rev-list --tags='[^ju]*' --max-count=1 HEAD) >/dev/null ; then
    echo "Failed to identify latest change, falling back to auto mode."
    git_dch_auto
  else
    identify_latest_change
  fi
fi

# get rid of "UNRELEASED" distribution header
debchange --release ""

# prepare orig.tar.gz using pristine-tar, but without actually building the source package
if [ "${IGNORE_GIT_BUILDPACKAGE:-}" = "true" ] ; then
  echo "Skipping git-buildpackage execution as requested via IGNORE_GIT_BUILDPACKAGE ***"
else
  git-buildpackage -nc --git-force-create --git-ignore-new -S -us -uc --git-verbose --git-builder=/bin/true --git-cleaner=/bin/true
fi

# build source package
( cd .. ; dpkg-source -i\.git -b source )

# revert to original debian/changelog to avoid merge conflicts
git checkout -- debian/changelog

# needed for deploying artifacts
mkdir -p ${JENKINS_HOME}/userContent/${JOB_NAME}/

echo "Cleaning up ${JENKINS_HOME}/userContent/${JOB_NAME} to get rid of possibly outdated data"
rm -f "${JENKINS_HOME}/userContent/${JOB_NAME}/"*

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