#!/bin/sh
set -e

###############################################################################
# This is the Ubuntu manpage repository generator and interface.
# 
# Copyright (C) 2008 Canonical Ltd.
# 
# This code was originally written by Dustin Kirkland <kirkland@ubuntu.com>,
# based on a framework by Kees Cook <kees@ubuntu.com>.
#
# It was later modified for Debian, for use in the debian-goodies package,
# by Antoine Beaupré <anarcat@debian.org>, Axel Beckert <abe@deuxchevaux.org>
# and Javier Fernández-Sanguino <jfs@debian.org>
# 
# 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/>.
# 
# On Debian-based systems, the complete text of the GNU General Public
# License can be found in /usr/share/common-licenses/GPL-3
###############################################################################


if [ -r /etc/lsb-release ] ; then
    . /etc/lsb-release
else
    DISTRIB_CODENAME=$(lsb_release -c -s 2>/dev/null)
fi
# default to stable if LSB fails or is absent
DISTRIB_CODENAME=${DISTRIB_CODENAME:-stable}

usage()
{
        echo "Usage: $0 [ --release suite ] man-page <man-arguments>"
}

download_man(){
    url=$1
    file=$2
    curl $CURLOPTS "$url" >"$file" 2>/dev/null
    if  ! [ -s "$file" ]  || 
        egrep -q "<title>403.*Forbidden</title>" "$file" ||
        egrep -q "<h1>Manpage not found</h1>" "$file"  ; then
            return 1
    fi
    return 0
}
    

# Process command line options
while true; do
	case "$1" in
		--release)
			DISTRIB_CODENAME="$2"
			shift 2
			;;
		--help)
                        usage
                        exit 0
                        ;;
		*)
			break
			;;
	esac
done
PAGE=`echo "$@" | awk '{print $NF}'`
MAN_ARGS=`echo "$@" | sed "s/\$PAGE$//"`



# Sanity checks
if [ ! -x "`which curl`" ] ; then
    echo "ERROR: $0 - cannot find curl - exiting"
    exit 1
fi
if [ -z "$PAGE" ] ; then
    echo "ERROR: No manpage provided - exiting"
    usage
    exit 1
fi

# PROGRAM OPTIONS
CURLOPTS="-s -L" # -s for silent, -L to follow redirects

# Mirror support of man's languages
if [ ! -z "$LANG" ]; then
	LOCALE=$(echo $LANG | sed 's/_.*$//')
	LOCDOT=".$LOCALE"
fi
if [ ! -z "$LC_MESSAGES" ]; then
	LOCALE="$LC_MESSAGES"
	LOCDOT=".$LOCALE"
fi
if echo $LOCALE | grep -E -q "^(C|en)"; then
	LOCALE=""
	LOCDOT=".en"
fi

BASE_URL="https://dyn.manpages.debian.org"

mandir=`mktemp --tmpdir="${TMPDIR:-/tmp}" -d dman.XXXXXX`
trap "rm -rf $mandir" EXIT HUP INT QUIT TERM
man="$mandir/$PAGE"

TESTED_URLS=""
# be careful not to add too many entries in this loop, as each hit can
# take some time for the round-trip
for URL in "$BASE_URL/$DISTRIB_CODENAME/$PAGE$LOCDOT.gz" \
               "$BASE_URL/$DISTRIB_CODENAME/$PAGE.en.gz" \
               "$BASE_URL/$DISTRIB_CODENAME/$PAGE.gz" \
               "$BASE_URL/$PAGE$LOCDOT.gz" \
               "$BASE_URL/$PAGE.en.gz" \
               "$BASE_URL/$PAGE.gz" \

do
    if download_man $URL $man; then
        man $MAN_ARGS -l "$man" || true
        exit 0
    fi
    # Continue in case of failure, take note of tested URL
    if [ -z "$TESTED_URLS" ] ; then
        TESTED_URLS="$URL" 
    else 
        TESTED_URLS="$TESTED_URLS, $URL"
    fi
done

echo "$0: not found. Tried: $TESTED_URLS" 1>&1
exit 1