#! /bin/bash

# grep-archive - wrapper to run grep-dctrl over a combination of dists,
# arches, and components in the Debian archive.
#
# Copyright (c) 2005, 2006 Adeodato Simó (dato@net.com.org.es)
# Licensed under the terms of the MIT license, included below.

# Takes a single argument (the rest are passed verbatim to grep-dctrl)
# in the form DIST:COMPONENT:ARCH, all three items being optional (but
# the colons must be present). Multiple values may be given separated
# by commas; the special value 'ALL' will use all the directories present
# in the mirror. The default is sid:main:`dpkg --print-architecture`.
# Some other examples:

#     sarge::ALL - main for all arches in sarge
#     etch:main,contrib:source - main and contrib for sources in etch
#     ::arm,m68k,hppa - unstable/main for arm, m68k, and hppa

MIRROR=${GREP_ARCHIVE_MIRROR:-/org/ftp.debian.org/ftp}

if ! command -v grep-dctrl >/dev/null 2>&1; then
    echo >&2 "E: grep-dctrl could not be found."
    exit 1
fi

# gzip is Essential: yes, bzip2 optional
if command -v bzcat >/dev/null 2>&1; then
    HAVE_BZCAT=yes
fi

###

cat_for_extension () {
    case "$1" in
    	'')   echo   cat ;;
	.gz)  echo  zcat ;;
	.bz2) echo bzcat ;;
    esac
}

###

ARGUMENT="$1"
shift

if ! echo "$ARGUMENT" | egrep -q "^[^: ]*:[^: ]*:[^: ]*$"; then
    echo >&2 "E: argument '$ARGUMENT' formatted incorectly (should be DIST:COMPONENT:ARCH)."
    exit 1
fi

###

DIST=$(      echo "$ARGUMENT" | cut -d: -f1 | tr , "\n" )
COMPONENT=$( echo "$ARGUMENT" | cut -d: -f2 | tr , "\n" )
ARCH=$(      echo "$ARGUMENT" | cut -d: -f3 | tr , "\n" )

# If 'ALL' is included, ignore the rest and eval `ALL` in the loop below.
# Can't expand it here since the available components may vary from dist
# to dist, or the available arches from dist/component to dist/component.

# FIXME - re-think this normalization, with it one would not get warnings
# for items explicitly mentioned in the command line and not present.

for v in DIST COMPONENT ARCH; do
    if echo "${!v}" | egrep -q 'ALL'; then
    	eval "${v}=ALL"
    fi
done

# Defaults
: ${DIST:=sid}
: ${COMPONENT:=main}
: ${ARCH:=`dpkg --print-architecture`}

###

the_dists () {
    if [ "$DIST" != "ALL" ]; then
    	echo $DIST
    else
    	cd "$MIRROR/dists" || return
	for d in *; do
	    if [ -d "$d" ] && ! [ -L "$d" ]; then
	    	echo $d
	    fi
	done
    fi
}

the_components () {
    if [ "$COMPONENT" != "ALL" ]; then
    	echo $COMPONENT
    else
    	cd "$MIRROR/dists/$1" || return
	for c in *; do
 	    # NOTE: nullglob set
	    if [ -d "$c/source" ] || [ $c/binary-* ]; then
	    	echo $c
	    fi
	done
    fi
}

the_arches () {
    if [ "$ARCH" != "ALL" ]; then
    	echo $ARCH
    else
    	cd "$MIRROR/dists/$1/$2" || return
	echo binary-* | sed -e 's/binary-//g'
    fi
}

###

shopt -s nullglob

CAT_FILES=""
prev_e="non-empty and not-a-valid-extension"

for d in `the_dists`; do
    for c in `the_components "$d"`; do
    	for a in `the_arches "$d" "$c"`; do
	    found=""

	    # TODO: add support for installer-*?
	    if [ "$a" = source ]; then
	    	b=
		n=Sources
	    else
	    	b=binary-
		n=Packages
	    fi

	    for e in '' .gz ${HAVE_BZCAT:+.bz2} ; do
	    	f="$MIRROR/dists/$d/$c/$b$a/$n$e"
	    	if [ -e "$f" ]; then
		    # Don't invoke extra processes unless necessary...
		    if [ "$e" = "$prev_e" ]; then
		    	CAT_FILES="$CAT_FILES $f"
		    else
		    	CAT_FILES="${CAT_FILES:+$CAT_FILES ;} `cat_for_extension $e` $f"
		    fi

		    if [ -n "$DEBUG_GREP_ARCHIVE" ]; then
		    	echo >&2 "I: Found: $d/$c/$a ($f)"
		    fi

		    found=1
		    prev_e="$e"
		    break
		fi
	    done

	    if [ -z "$found" ]; then
	    	echo >&2 "W: Not found: $d/$c/$a (${f%%$e})"
	    fi
	done
    done
done

if [ -z "$DEBUG_GREP_ARCHIVE" ]; then
    eval $CAT_FILES | grep-dctrl "$@"
fi

###

# MIT LICENSE (http://www.opensource.org/licenses/mit-license.php)

# 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.