#!/bin/bash
# Distributed under the terms of the GNU General Public License v3 or later
# AUTHOR: Loïc Cerf
# e-mail: magicbanana@gmail.com

WGET_OPT="-q -c"

EX_USAGE=64
EX_NOHOST=68

manual ()
{
    echo "Usages: $0 [ OPTIONS ] album-url [ destination ]
        $0 [ OPTIONS ] gallery-url [ destination ]
        $0 [ OPTIONS ] directory [ destination ]
        $0 [ OPTIONS ] list-file [ destination ]

OPTIONS:
-h (--help): produce help message
-V (--version): display version information and exit

-a (--albums): do not download, list the new albums' URLs
-l (--list): do not dowload, list the new pictures

-n (--no-gallery): no \"gallery\" level of directories"
}

recurse ()
{
    if [ -n "$printUrlMode" -o -n "$listMode" ]
    then
	$command "$1" "$destination"
    else
	$command "$1" "$destination" &
    fi
}

structure ()
{
    if [ -z "$printUrlMode" -a -z "$listMode" ]
    then
	if [ -f "$destination"/.picasaweb-download ]
	then
	    if ! grep -m 1 ^$1$ "$destination"/.picasaweb-download > /dev/null
	    then
		echo $1 >> "$destination"/.picasaweb-download
	    fi
	else
	    mkdir -p "$destination"
	    echo $1 >> "$destination"/.picasaweb-download
	fi
    fi
}

proceedAlbum ()
{
    structure $arg
    cat $temp1 | tr '{' '\n' | grep "^\"url\":\"" > $temp2
    rm $temp1
    while read picture
    do
	pictureUrl=${picture#\"url\":\"}
	pictureUrl=${pictureUrl%%\"*}
        pictureName=${pictureUrl##*/}
	pictureName=${pictureName//%25/%}
	pictureName=`echo $pictureName | perl -MURI::Escape -lne 'print uri_unescape($_)'`
	echo "$pictureName/$pictureUrl" >> $temp1
    done < $temp2
    sort -t / -k 1,1 $temp1 > $temp2
    while IFS=/ read pictureName pictureUrl
    do
# Rename the picture if its name was previously encountered
	if [ "$pictureName" = "$oldPictureName" ]
	then
	    let "counter += 1"
	    out="$destination/${pictureName%.*} $counter.${pictureName##*.}"
	else
	    oldPictureName="$pictureName"
	    counter=1
	    out="$destination/$pictureName"
	fi
	if [ -n "$listMode" ]
	then
# Print the name of the picture
	    if [ ! -f "$out" ]
	    then
		echo "${out#./}"
	    fi
	else
# Download the picture
	    wget $WGET_OPT -O "$out" $pictureUrl &
	fi
    done < $temp2
}

proceedSpecialCharacters ()
{
    string="${1//'\x26#39\x3B'/\'}"
    string="${string//'\x26quot\x3B'/\"}"
    string="${string//'\x26amp\x3B'/&}"
    string="${string//'\x3B'/;}"
    string="${string//'\x5C'/ }"
    echo ${string//'\x0A'/ }
}

proceedSpecialCharactersURL ()
{
    url=`proceedSpecialCharacters "$1"`
    echo ${url//'\x2F'//}
}

proceedSpecialCharactersFile ()
{
    file=`proceedSpecialCharacters "$1"`
    echo ${file//'\x2F'/ }
}

command="$0"
while [ -n "$1" ]
do
    case "$1" in
	-h | --help ) manual
	    exit;;
	-V | --version ) echo "picasaweb-download 0.1.1"
	    exit;;
	-a | --albums ) command="$command -a"
	    printUrlMode="y";;
	-l | --list ) command="$command -l"
	    listMode="y";;
	-n | --no-gallery ) command="$command -n"
	    noGalleryDirectory="y";;
	* ) if [ -z "$arg" ]
	    then
	    arg="${1#http://}"
	    elif [ -z "$destination" ]
	    then
	    destination="$1"
	    else
	    manual
	    exit $EX_USAGE
	    fi;;
    esac
    shift 1
done
if [ -z "$arg" ]
then
    manual
    exit $EX_USAGE
fi
if [ -d "$arg" ]
then
# echo "$arg is the directory of previously downloaded galleries/albums"
    if [ ! -f "$arg"/.picasaweb-download ]
    then
	echo "\"$arg\" is not the directory
of a previously downloaded album (or gallery)" 1>&2
	exit
    fi
    arg="$arg"/.picasaweb-download
fi
if [ -f "$arg" ]
then
# echo "$arg is a list of galleries/albums"
    while read url
    do
	recurse $url
    done < "$arg"
    exit
fi
page=${arg#picasaweb.google.*/}
if [ "$page" = "$arg" ]
then
    echo "\"$arg\" is neither the URL of a PicasaWeb album (or gallery)
nor the directory of a previously downloaded album (or gallery)" 1>&2
    exit $EX_USAGE
fi
if [ -z "$destination" ]
then
    destination=.
fi
temp1=`mktemp`
trap "rm $temp1 2>/dev/null" EXIT
temp2=`mktemp`
trap "rm $temp2 2>/dev/null" EXIT
suffix=${page#*/}
if [ -z "$suffix" -o "$suffix" = "$page" ]
then
# echo "$arg is a gallery URL"
    if wget $WGET_OPT -O $temp1 "$arg"
    then
	grep "^,url:'" $temp1 > $temp2
	while read -r url
	do
	    url=${url#",url:'"}
	    recurse `proceedSpecialCharactersURL ${url%\'}`
	done < $temp2
    else
	exit $EX_NOHOST
    fi
else
# echo "$arg is an album URL"
    if ! wget $WGET_OPT -O $temp1 "$arg"
    then
	echo "The album $arg cannot be found.
Are you connected to Internet? Is the URL correct?" 1>&2
	exit $EX_NOHOST
    fi
    if [ -z "$noGalleryDirectory" ]
    then
	galleryName=`grep -m 1 "^var _user" $temp1`
	galleryName="${galleryName##*,nickname:\'}"
	destination="$destination"/`proceedSpecialCharactersFile "${galleryName%%\'*}"`
	structure ${arg%/*}
    fi
    album=`grep -m 1 "^var _album" $temp1`
    albumName="${album##*,title:\'}"
    destination="$destination"/`proceedSpecialCharactersFile "${albumName%%\'*}"`
    if [ -n "$printUrlMode" ]
    then
	if [ ! -d "$destination" ]
	then
	    echo $arg
	fi
	if [ -n "$listMode" ]
	then
	    proceedAlbum
	fi
    else
	proceedAlbum
    fi
fi