#!/bin/sh

# source-tools - Manage Git repositories effectively and efficiently
# Copyright (C) 2014-2017 Daniel Baumann <daniel.baumann@open-infrastructure.net>

set -e

# FIXME: handle backports specific changelog entry.

# Assumptions:
#
# * the repository is using pristine-tar for non-native packages.
# * release commits, if any, are of the form 'Releasing debian version ...'.
# * import commits, if any, are of the form 'Adding debian version ...'.
# * the repository has at least either of a release or an import commit on the
#   target branch.
# * and finally, the target branch is including upstream sources, not just
#   debianization. but that should be clear anyway.


# Check depends
for FILE in git git-dch dpkg-parsechangelog pristine-tar
do
	if [ ! -x "$(which ${FILE} 2>/dev/null)" ]
	then
		echo "${FILE} missing, aborting."
		exit 1
	fi
done

# Arguments
if [ -z "${1}" ]
then
	echo "Usage: ${0} REPOSITORY [DISTRIBUTION] [BRANCH]"
	exit 1
fi

REPOSITORY="${1}"
DISTRIBUTION="${2:-UNRELEASED}"
BRANCH="${3}"

# Dynamic variables
PACKAGE="$(basename ${REPOSITORY} .git)"

# Static variables
TEMPDIR="$(mktemp -d -t git-dpkg-source.XXXXXXXX)"
CURDIR="${PWD}"

################################################################################

# Creating build directory
mkdir -p "${TEMPDIR}"

# Cloning sources
cd "${TEMPDIR}"
git clone ${REPOSITORY}

# Checking out branch
cd "${TEMPDIR}"/${PACKAGE}

if [ -n "${BRANCH}" ] && [ ! "$(git branch | awk '/^\* / { print $2 }')" = "${BRANCH}" ] &&
   [ -n "$(git branch -r | grep ${BRANCH}$ )" ]
then
	# user specified a branch because he wants to build what is not
	# the default branch of his repository, also:
	# we are not on that target branch, but the target branch exists,
	# so we check it out and switch to it.
	git checkout -b ${BRANCH} origin/${BRANCH} || true
fi

# Assemble version information
VERSION="$(dpkg-parsechangelog | awk '/Version:/ { print $2 }' | sed -e 's|.*:||')"
UPSTREAM_VERSION="$(echo ${VERSION} | sed -e 's|-.*||')"

if echo $(dpkg-parsechangelog | awk '/Version:/ { print $2 }')| grep -q ":"
then
	EPOCHE="$(dpkg-parsechangelog | awk '/Version:/ { print $2 }' | awk -F: '{ print $1 }'):"
else
	EPOCHE=""
fi

# let's see if we have a newer upstream version checked in
if git branch -r | grep -q pristine-tar
then
	TAR_VERSION="$(git show origin/pristine-tar | awk -F_ '/^\+\+\+(.*)tar.gz.id$/ { print $2 }' | sed -e 's|.orig.tar.gz.id||' -e 's|.tar.gz.id||')"
fi

DELIMETER=""

if [ -n "${TAR_VERSION}" ] && [ "${UPSTREAM_VERSION}" != "${TAR_VERSION}" ]
then
	# there has been newer upstream version merged
	# (means: head has newer upstream than last release commit)
	VERSION="${TAR_VERSION}-"
	UPSTREAM_VERSION="${TAR_VERSION}"
	DELIMETER="~"
else
	VERSION="${VERSION}"
fi

# let's see if the last commit was a release or import commit.
# FIXME: it's more generic to compare if the last commit matches any available tag.
if [ -z "$(git log | grep -m1 Date -A2 | grep "Releasing debian version ")" ] && \
   [ -z "$(git log | grep -m1 Date -A2 | grep "Adding debian version ")" ] && \
   [ -z "$(git log | grep -m1 Date -A2 | grep "Releasing version ")"] && \
   [ -z "$(git log | grep -m1 Date -A2 | grep "Adding version ")" ]
then
	# we are building a snapshot
	if [ -z "${DELIMETER}" ]
	then
		DELIMETER="+"
	fi

	# building version string from date of last commit
	REVISION="$(git log | grep -m1 Date | awk -FDate: '{ print $2 }' | awk '{ print $1 ",", $3, $2, $5, $4, $6 }')"
	REVISION="${DELIMETER}$(date -d "${REVISION}" +%Y%m%d.%H%M%S)"
else
	# we are building a release
	REVISION=""
fi

HASH="$(cd "${TEMPDIR}"/${PACKAGE} && git log | grep -m1 commit | awk '{ print $2 }')"

# Renaming package directory (in case we are building native,
# it would matter for cosemtics; if non-native it's ignored anyway)
mv "${TEMPDIR}"/${PACKAGE} "${TEMPDIR}"/${PACKAGE}-${VERSION}${REVISION}

# Creating changelog
cd "${TEMPDIR}"/${PACKAGE}-${VERSION}${REVISION}

if [ -z "${DEBFULLNAME}" ]
then
	if [ -n "$(git config --get user.name)" ]
	then
		# take name from git config
		DEBFULLNAME="$(git config --get user.name)"
	else
		# or from last commit in the repository
		DEBFULLNAME="$(git log | grep -m1 "^Author: " | sed -e 's|^Author: ||' -e 's| <.*>$||')"
	fi
fi

if [ -z "${DEBEMAIL}" ]
then
	if [ -n "$(git config --get user.email)" ]
	then
		# take email from git config
		DEBEMAIL="$(git config --get user.email)"
	else
		# or from last commit in the repository
		DEBEMAIL="$(git log | grep -m1 "^Author: " | sed -e 's|^.*<||' -e 's|>$||')"
	fi
fi

export DEBFULLNAME DEBEMAIL

if [ -n "${REVISION}" ]
then
	# we are building a snapshot, let's get the hash of the last release
	OLD_HASH="$(git log | grep -B4 -m1 'Releasing debian version ' | awk '/commit / { print $2 }')"
	if [ -z "${OLD_HASH}" ]
	then
		# if there wasn't a release commit, maybe just have an import commit.
		OLD_HASH="$(git log | grep -B4 -m1 'Adding debian version ' | awk '/commit / { print $2 }')"
	fi

	# Add git commit messages since the last release/import.
	echo "Running git-dch..."
	git-dch --debian-branch $(git branch | awk '/^\* / { print $2 }') --since ${OLD_HASH} --new-version ${EPOCHE}${VERSION}${REVISION}

	# Create changelog top note.
	HEADER="$(head -1 debian/changelog)"
	sed -i -e '1 d' debian/changelog

	mv debian/changelog debian/changelog.tmp

#case "${DISTRIBUTION}" in
#	lenny-backports)
#
#cat > debian/changelog << EOF
#${HEADER}
#
#  * Rebuilding for Debian GNU/Linux 5.0 "lenny".
#EOF
#
#		;;
#
#	sid-snapshots)
#
cat > debian/changelog << EOF
${HEADER}

  * Unreleased snapshot from Git repository:
    ${HASH}
EOF

#		;;
#esac

	cat debian/changelog.tmp >> debian/changelog
	rm -f debian/changelog.tmp

	dch --distribution ${DISTRIBUTION} --force-distribution --release ""
#	--append "Unreleased snapshot from Git repository: ${HASH}"
else
	# we are building a release

	case "${DISTRIBUTION}" in
		sid-snapshots)
			dch --force-distribution --force-bad-version --newversion ${EPOCHE}${VERSION}${REVISION} --distribution ${DISTRIBUTION} "Rebuild release from Git repository: ${HASH}"
			;;
	esac
fi

# Getting orig.tar.gz
if [ -n "${TAR_VERSION}" ]
then
	# we have a non-native package
	pristine-tar checkout ${PACKAGE}_${UPSTREAM_VERSION}.orig.tar.gz
	mv ${PACKAGE}_${UPSTREAM_VERSION}.orig.tar.gz ../
fi

# Building package
cd "${TEMPDIR}"/
rm -rf ${PACKAGE}-${VERSION}${REVISION}/.git
dpkg-source -b ${PACKAGE}-${VERSION}${REVISION}

# Removing sources
rm -rf ${PACKAGE}-${VERSION}${REVISION}
mv * ${CURDIR}
rm -rf "${TEMPDIR}"