#! /bin/sh

# Copyright (C) 2010 Carsten Hey <carsten@debian.org>
# Published under the terms of the MIT license
# and provided without warranty of any kind.

set -u
set -e

gen_changelog() {
    local CHANGELOG="${1:?}"
    shift

    local DCH="dch --no-conf --no-auto-nmu --noquery \
                   --force-distribution --distribution unstable \
                   --changelog $CHANGELOG"

    if ! [ -f "$CHANGELOG" ]
    then # create new changelog file
        $DCH --newversion "0.0.0~$(date '+%Y%m%d')" \
             --package    "$DIR2DEB_PACKAGENAME" \
             --create     "Initial release."
    else # increment version number and add new entry
        local OLD_VERSION="$( dpkg-parsechangelog -l"$CHANGELOG" \
                            | awk '/^Version: / { print $2 }' )"
        local NEW_VERSION="0.0.0~$( date '+%Y%m%d' )"

        if [ "$OLD_VERSION" = "$NEW_VERSION" ]
        then # append +1 to old version number
            NEW_VERSION="$OLD_VERSION+1"
        elif printf '%s\n' "${OLD_VERSION#$NEW_VERSION}" \
             | grep -qE '^\+[0-9]+$'
        then # increment old version number by 1
            NEW_VERSION="${NEW_VERSION}+$(( 1 $( printf '%s\n' "$OLD_VERSION" \
                                               | grep -oE '\+[0-9]+$' ) ))"
        fi

        $DCH --newversion "$NEW_VERSION" \
                          "New release."
    fi
}
gen_compat() {
    local FILENAME="${1:?}"
    shift

    if [ -e "$FILENAME" ]; then return 0; fi

    echo "$DIR2DEB_COMPAT" > "$FILENAME"
}
gen_control() {
    local FILENAME="${1:?}"
    shift

    if [ -e "$FILENAME" ]; then return 0; fi

    cat > "$FILENAME" <<- EOH
	Source: $DIR2DEB_PACKAGENAME
	Section: misc
	Priority: optional
	Maintainer: ${DEBFULLNAME:?} <${DEBEMAIL:?}>
	Build-Depends: debhelper (>= ${DIR2DEB_COMPAT})
	Standards-Version: $DIR2DEB_STANDARDS_VERSION
	
	Package: $DIR2DEB_PACKAGENAME
	Architecture: all
	Depends: \${misc:Depends}
	Description: No description yet.
	 No long description yet.
EOH
} # }}}
gen_copyright() {
    local FILENAME="${1:?}"
    shift

    if [ -e "$FILENAME" ]; then return 0; fi

    cat > "$FILENAME" <<- EOH
	[ Do not upload with this minimalistic debian/copyright file! ]
	
	Please check indivudal files in this package for their copyright and
	license information.
EOH
}
gen_rules() {
    local FILENAME="${1:?}"
    shift

    if [ -e "$FILENAME" ]; then return 0; fi

    cat > "$FILENAME" << "EOH"
#!/usr/bin/make -f

build clean : ; dh $@
binary      : binary-arch binary-indep
binary-%    : install ; dh $@

install : build install-stamp
install-stamp:
	dh_testdir
	dh_testroot
	dh_prep
	dh_installdirs
	
	test -d "`pwd`/debian/`dh_listpackages`"
	find . -mindepth 1 -maxdepth 1 -type d ! -name debian \
	       -exec cp -a '{}' "`pwd`/debian/`dh_listpackages`" ';'
	
	touch $@
EOH

    chmod a+rx "$FILENAME"
}

dir="${1:?please specify directory\n}"
shift

DIR2DEB_COMPAT="7"
DIR2DEB_STANDARDS_VERSION="3.8.4"
DIR2DEB_PACKAGENAME="$(cd $dir ; basename `pwd`)"
: ${DEBFULLNAME:?you need to set $DEBFULLNAME\n}
: ${DEBEMAIL:?you need to set $DEBEMAIL}

if   [ ! -d "$dir/debian" ] \
  && [ ! -d "$dir/bin" ] \
  && [ ! -d "$dir/boot" ] \
  && [ ! -d "$dir/etc" ] \
  && [ ! -d "$dir/lib" ] \
  && [ ! -d "$dir/sbin" ] \
  && [ ! -d "$dir/usr" ] \
  && [ ! -d "$dir/var" ]
then
    echo "Can't find package directory in \"$dir\"" >&2
    exit 1
fi

if   [ ! -d "$dir/debian" ]; then
    mkdir "$dir/debian"
fi

gen_changelog "$dir/debian/changelog"
gen_compat    "$dir/debian/compat"
gen_control   "$dir/debian/control"
gen_copyright "$dir/debian/copyright"
gen_rules     "$dir/debian/rules"