#!@SH@
#-*-mode:  sh -*-

# Copyright (c) 2007-2008 Aleksey Cheusov <vle@gmx.net>
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

set -e

. pipestatus

usage (){
    cat 1>&2 <<EOF
pkg_update_summary - updates pkg_summary(5) efficiently

usage: pkg_update_summary [OPTIONS] summary_file bin_pkg_dir [decomp comp]
OPTIONS:
  -h|--help      display this help message
  -r|--refresh   keeps only latest version for each pkgpath:pkgbase pair
EOF
}

refresh=cat
while test $# -ne 0; do
    case "$1" in
	-h|--help)
	    usage
	    exit 0;;
	-r|--refresh)
	    refresh=pkg_refresh_summary;;
	--)
	    shift
	    break;;
	-*)
	    echo "Bad option $1" 1>&2
	    exit 1;;
	*)
	    break
    esac
    shift
done

PKG_SUFX=${PKG_SUFX:=@PKG_SUFX@}
PKG_SUFX_RE="`echo $PKG_SUFX | sed 's,[.],[.],g'`"

PKG_INFO_CMD="${PKG_INFO_CMD:=@PKG_INFO_CMD@}"

if test -z "$TEST_CMD"; then
    TEST_CMD=test
fi

if test $# -eq 2; then
    summary_file="$1"
    bin_pkg_dir="$2"
    uncompress='cat'
    compress='cat'
elif test $# -eq 4; then
    summary_file="$1"
    bin_pkg_dir="$2"
    uncompress="$3"
    compress="$4"
else
    usage
    exit 1
fi

cd "$bin_pkg_dir"

# do not run the command when there is NO input on stdin
xargs_bsdstyle (){
    awk -v cmd="xargs $*" '{print $0 | cmd}'
}

pkgs2summary (){
    xargs_bsdstyle $PKG_INFO_CMD -X
}

get_all_pkgs (){
    # in order to ignore grep's exit status in case
    # binary packages directory is empty
    runpipe_re '0 [01]' ls -1t "$bin_pkg_dir" '|' grep "$PKG_SUFX_RE"'$'
}

get_updated_pkgs (){
    get_all_pkgs |
    while read f; do
	if $TEST_CMD "$f" -nt "$summary_file"; then
	    echo "$f"
	else
	    break
	fi
    done
}

print_uniq (){
    awk '$1 == 1 {print $2}'
}

subtract (){
    runpipe0 \
	env LC_ALL=C sort "$@" '|' \
	env LC_ALL=C uniq -c '|' \
	print_uniq
}

get_unchanged_pkgs (){
#    echo "updated=$updated"
#    echo "all=$all"
    { echo "$all"; echo "$updated"; } | subtract
}

tmpbase="`dirname $summary_file`/`basename $summary_file`.tmp"
tmpfinal="$tmpbase.final"
tmp2="$tmpbase.tmp2"

if test -z "$TRACE"; then
    trap "rm -f $tmpfinal $tmp2" 0 1 2 15
fi

filter_unchanged (){
    pkgs_fn=$1
    shift

    awk -v pkgs_fn="$pkgs_fn" -v PKG_SUFX_RE="$PKG_SUFX_RE" '
    BEGIN {
	while (0 < (ret = getline < pkgs_fn)){
	    sub(PKG_SUFX_RE "$", "")
	    keep_array [$1] = ""
	}
	if (ret < 0){
	    printf "reading from %s failed\n", pkgs_fn > "/dev/stderr"
	    exit 2
	}

	FS = "="
    }
    NF > 0, NF == 0 {
	if (accu == "")
	    accu = $0
	else
	    accu = accu "\n" $0

	if ($1 == "PKGNAME"){
	    pkgname = $2
	    next
	}

	if (NF > 0){
	    next
	}

        keep = (pkgname in keep_array)

	if (keep){
	    print accu
	}

	accu = ""
    }
    ' "$@"
}

show_debugging_info (){
    if test -n "$TRACE"; then
	printf "$all" > "$tmpbase.all"

	printf "$updated" > "$tmpbase.updated"

	if test -f "$summary_file"; then
	    { echo "$all" | sed 's/[.][^.]*$//'
		sed -n 's/^PKGNAME=//p' "$summary_file"
	    } | subtract > "$tmpbase.removed"
	else
	    printf '' > "$tmpbase.removed"
	fi

	echo "See $tmpbase.{all,updated,removed,final,tmp2} files" 1>&2
    fi
}

update_summary (){
    updated="`get_updated_pkgs`"
    all="`get_all_pkgs`"
    get_unchanged_pkgs > "$tmp2"

    runpipe0 $uncompress "$summary_file" '|' filter_unchanged "$tmp2"
    if test -n "$updated"; then
	runpipe0 echo "$updated" '|' pkgs2summary
    fi
}

if test -f "$summary_file"; then
    runpipe0 \
	update_summary '|' \
	$refresh '|' \
	$compress > "$tmpfinal"
else
    runpipe0 \
	get_all_pkgs '|' \
	pkgs2summary '|' \
	$refresh '|' \
	$compress > "$tmpfinal"
fi

show_debugging_info

if test -z "$TRACE"; then
    mv "$tmpfinal" "$summary_file"
fi