#!@@SHELL@@
#
# DEB - Download, Edit, Build!
# src/deb.sh
# Main program script.
#
# Copyright (C) 2012 Patrick "P. J." McDermott
#
# This program 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 3 of the License, or
# (at your option) any later version.
#
# This program 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, see <http://www.gnu.org/licenses/>.

COMMANDS='init config update download edit builddsc push'
CONFIG_NAMES='mirror distribution component remote buildcmd'

main()
{
	SCRIPT_NAME="${0}"

	if [ ${#} -lt 1 ]; then
		print_usage >&2
		exit 1
	fi

	COMMAND_NAME="${1}"
	shift

	if ! echo " ${COMMANDS} " | grep " ${COMMAND_NAME} " > /dev/null 2>&1; then
		print_usage >&2
		exit 1
	fi

	CWD="${PWD}"

	cmd_run ${@}
}

print_usage()
{
	cat <<EOF
Usage: ${SCRIPT_NAME} <command> <arguments>

Where <command> is one of:
  init      Initialize a DEB work area
  config    Get or set a configuration value
  update    Update the list of source packages
  download  Download a source package
  edit      Unpack a source package for editing
  builddsc  Build an edited source package and debdiff
  build     Build binary packages
  push      Synchronize changes with a remote tree
EOF
}

error()
{
	_msg="${1}"
	shift
	printf "Error: ${_msg}\n" ${@} >&2
	exit 2
}

find_deb_dir()
{
	until [ "${PWD}" = '/' ]; do
		if [ -d '.deb' ]; then
			DEB_DIR="${PWD}/.deb"
			DEB_TREE="${PWD}"
			return 0
		fi
		cd ..
	done
	[ ${#} -ge 1 ] && "${1}" && error 'No DEB work area found'
	return 1
}

config_load()
{
	. "${DEB_DIR}/config"
}

config_save()
{
	for _name in ${CONFIG_NAMES}; do
		printf "CONFIG_%s='%s'\n" "${_name}" "$(eval echo \$\{CONFIG_${_name}\})"
	done > "${DEB_DIR}/config"
}

get_dsc_url()
{
	[ ! -f "${DEB_DIR}/dsc.list" ] && error 'No source package list found'
	_pkg="${1}"
	_dscurl=$(grep "^${_pkg} " "${DEB_DIR}/dsc.list" | tail -n 1) || \
		error 'Package "%s" not found' "${pkg}"
	echo "${_dscurl#${_pkg} }"
}

get_dsc_name()
{
	_pkg="${1}"
	_dscurl="$(get_dsc_url "${pkg}")"
	echo "${_dscurl##*/}"
}

prompt_bool()
{
	_def="${1}"
	_prompt="${2}"
	shift 2
	[ "${_def}" = y ] && _yn='[Y/n]' || _yn='[y/N]'
	printf "${_prompt}  ${_yn} " $@

	read _val
	[ "${_val}" = y ] && return 0
	[ "${_val}" = n ] && return 1
	[ "${_def}" = y ] && return 0 || return 1
}

cmd_run()
{
	"cmd_${COMMAND_NAME}" ${@}
}

cmd_init()
{
	find_deb_dir false || {
		DEB_DIR="${CWD}/.deb"
		DEB_TREE="${CWD}"
	}

	CONFIG_mirror='http://ftp.debian.org/debian'
	CONFIG_distribution='sid'
	CONFIG_component='main'
	CONFIG_buildcmd='sbuild --build=%mirror% -d %distribution% %opts% %dsc%'

	cd "${DEB_TREE}"
	if [ -d .deb ]; then
		prompt_bool n 'DEB work area exists.  Reinitialize?' || exit
		rm -Rf .deb dsc builds pkgs work
		mkdir .deb dsc builds pkgs work
		config_save
		printf 'Reinitialized DEB work area in %s.\n' "${DEB_TREE}"
	else
		mkdir .deb dsc builds pkgs work
		config_save
		printf 'Initialized DEB work area in %s.\n' "${DEB_TREE}"
	fi
}

cmd_config()
{
	find_deb_dir
	config_load

	if [ ${#} -ne 1 -a ${#} -ne 2 ]; then
		cat >&2 <<EOF
Usage: ${SCRIPT_NAME} ${COMMAND_NAME} <name> [<value>]
EOF
		exit 1
	fi
	
	echo " ${CONFIG_NAMES} " | grep " ${1} " > /dev/null 2>&1 || \
		error 'Invalid configuration name "%s"' "${1}"

	config_name="CONFIG_${1}"
	if [ ${#} -eq 1 ]; then
		printf '%s\n' "$(eval echo \$\{${config_name}\})"
	else
		eval "${config_name}=${2}"
		config_save
	fi
}

cmd_update()
{
	find_deb_dir
	config_load

	if [ ${#} -ne 0 ]; then
		cat >&2 <<EOF
Usage: ${SCRIPT_NAME} ${COMMAND_NAME}
EOF
		exit 1
	fi

	printf 'Downloading Sources file...\n'
	rm -f "${DEB_DIR}/.Sources.bz2"
	sources="${CONFIG_mirror}/dists/${CONFIG_distribution}/${CONFIG_component}/source"
	sources="${sources}/Sources.bz2"
	curl -o "${DEB_DIR}/.Sources.bz2" "${sources}" || error 'Cannot download Sources file'

	printf '\nDecompressing Sources file...\n'
	rm -f "${DEB_DIR}/.Sources"
	bunzip2 "${DEB_DIR}/.Sources.bz2" || error 'Cannot decompress Sources file'

	total=$(grep ^Package: "${DEB_DIR}/.Sources" | wc -l)
	count=0

	printf '\nReading Sources file...\n'
	> "${DEB_DIR}/.dsc.list~"
	while read line; do
		if [ -z "${line}" ]; then
			printf '%s %s\n' "${pkg}" "${dir}/${dsc}" >> "${DEB_DIR}/.dsc.list~"
			count=$(($count + 1))
			printf "\rFound %${#total}d/%d source packages.%s" \
				"${count}" "${total}" \
				"$([ ${count} -eq ${total} ] && printf '  ' || printf '..')"
			continue
		fi
		if [ "${line#Package: }" != "${line}" ]; then
			pkg="${line#Package: }"
			continue
		fi
		if [ "${line#Directory: }" != "${line}" ]; then
			dir="${line#Directory: }"
			continue
		fi
		if [ "${line#Files:}" != "${line}" ]; then
			while read sum size file; do
				if [ "${file%.dsc}" != "${file}" ]; then
					dsc="${file}"
					break
				fi
			done
			continue
		fi
	done < "${DEB_DIR}/.Sources"
	printf '\n'

	rm "${DEB_DIR}/.Sources"
	mv "${DEB_DIR}/.dsc.list~" "${DEB_DIR}/dsc.list"

	printf '\nDone.\n'
}

cmd_download()
{
	find_deb_dir
	config_load

	if [ ${#} -ne 1 ]; then
		cat >&2 <<EOF
Usage: ${SCRIPT_NAME} ${COMMAND_NAME} <pkg>
EOF
		exit 1
	fi

	pkg="${1}"

	# Get URL to DSC file.
	dscurl="$(get_dsc_url "${pkg}")"

	# Create clean destination for source package files.
	rm -Rf "${DEB_TREE}/dsc/${pkg}"
	mkdir -p "${DEB_TREE}/dsc/${pkg}"
	cd "${DEB_TREE}/dsc/${pkg}"

	# Download source package files.
	printf 'Downloading source package "%s"...\n' "${pkg}"
	dget -d "${CONFIG_mirror}/${dscurl}" || error 'Cannot download source package'

	printf '\nDone.\n'
}

cmd_edit()
{
	find_deb_dir
	config_load

	if [ ${#} -ne 1 ]; then
		cat >&2 <<EOF
Usage: ${SCRIPT_NAME} ${COMMAND_NAME} <pkg>
EOF
		exit 1
	fi

	pkg="${1}"

	# Get name of DSC file.
	dsc="$(get_dsc_name "${pkg}")"

	# Ensure that source package is downloaded.
	[ ! -f "${DEB_TREE}/dsc/${pkg}/${dsc}" ] && \
		error 'Source package "%s" not downloaded' "${pkg}"

	ver="${dsc%.dsc}"
	ver="${ver#${pkg}_}"
	ver="${ver%-*}"

	# Check if source package is already unpacked.
	if [ -d "${DEB_TREE}/work/${pkg}/${pkg}-${ver}" ]; then
		prompt_bool n \
			'Source package "%s" already unpacked for editing.  Remove?' \
			"${pkg}" || exit
	fi

	# Create clean work area for source package.
	rm -Rf "${DEB_TREE}/work/${pkg}"
	mkdir -p "${DEB_TREE}/work/${pkg}"

	# Unpack source package.
	dpkg-source -x "${DEB_TREE}/dsc/${pkg}/${dsc}" \
		"${DEB_TREE}/work/${pkg}/${pkg}-${ver}"
}

cmd_builddsc()
{
	find_deb_dir
	config_load

	if [ ${#} -ne 1 ]; then
		cat >&2 <<EOF
Usage: ${SCRIPT_NAME} ${COMMAND_NAME} <pkg>
EOF
		exit 1
	fi

	pkg="${1}"

	# Find source package in internal list.
	dsc="$(get_dsc_name "${pkg}")"

	# Ensure that source package is unpacked.
	[ ! -d "${DEB_TREE}/work/${pkg}/${pkg}-*" ] && \
		error 'Source package "%s" not unpacked for editing' "${pkg}"

	# Get source package version from internal list.
	oldverrev="${dsc%.dsc}"
	oldverrev="${oldverrev#${pkg}_}"

	# Get source package version from work area.
	verrev="$(dpkg-parsechangelog \
		-l"${DEB_TREE}/work/${pkg}/${pkg}-*/debian/changelog" | \
		sed -n 's/^Version: \(.*\)$/\1/p')"
	pkgverrev="${pkg}_${verrev}"
	ver="${verrev%-*}"
	rev="${verrev#*-}"

	# Ensure that an NMU was made.
	dpkg --compare-versions "${verrev}" gt "${oldverrev}" || \
		error 'Version not incremented'

	# Build source package.
	cd "${DEB_TREE}/work/${pkg}/${pkg}-*"
	dpkg-buildpackage -S -us -uc

	# Make a clean source package destination.
	cd ..
	rm -Rf "${DEB_TREE}/pkgs/${pkg}"
	mkdir -p "${DEB_TREE}/pkgs/${pkg}"

	# Copy source package files.
	while read line; do
		if [ "${line#Files:}" != "${line}" ]; then
			while read sum size file; do
				case "${file}" in
					*.orig.tar.*)
						cp -p "${file}" "${DEB_TREE}/pkgs/${pkg}"
						;;
					*)
						mv "${file}" "${DEB_TREE}/pkgs/${pkg}"
			done
		fi
	done < "${pkgverrev}.dsc"
	mv "${pkgverrev}.dsc" "${pkgverrev}_source.changes" "${DEB_TREE}/pkgs/${pkg}"

	# Generate patch.
	debdiff \
		"${DEB_TREE}/dsc/${pkg}/${dsc}" "${DEB_TREE}/pkgs/${pkg}/${pkgverrev}.dsc" \
		> "${DEB_TREE}/pkgs/${pkg}/${pkg}.debdiff"
}

cmd_push()
{
	find_deb_dir
	config_load

	if [ ${#} -ne 0 ]; then
		cat >&2 <<EOF
Usage: ${SCRIPT_NAME} ${COMMAND_NAME}
EOF
		exit 1
	fi

	rsync -az --stats "${DEB_TREE}/pkgs/" "${CONFIG_remote}/pkgs/"
	rsync -az --stats "${DEB_TREE}/builds/" "${CONFIG_remote}/builds/"
}

main ${@}