#!/bin/bash
#
#  xsltrans [options] <xmlfile> [<xslfile>]
#
#  This little utility script will call the XSL transformator of your choice.
#
#  Options:
#     -p, --param name=value          Set XSL XPATH parameter
#     -s, --stringparam name=value    Set XSL string parameter
#
#  The <xmlfile> is the input XML file. The <xslfile> is the XSL stylesheet.
#  If you have a xml-stylesheet processing instruction in your XML file,
#  you don't need to add the <xslfile>. Output is always on STDOUT.
#
#  If the environment variable XSLTRANS is set, it will call the program
#  named in the variable. If the content of XSLTRANS ends in .jar, it will
#  call java with this JAR file as a parameter.
#
#  xsltrans knows the calling syntax of xsltproc, xmlstarlet, xalan (c++)
#  and xalan (Java) and will supply the parameters in the right form.
#  Note that not all programs support all options.
#

#set -x

prgname=`basename $0`

function usage() {
    echo >&2 "Usage: $prgname [options] <xmlfile> [<xslfile>]"
    echo >&2 "Options: -p, --param name=value          Set XSL XPATH parameter"
    echo >&2 "         -s, --stringparam name=value    Set XSL string parameter"
}

paralist=$(getopt --unquoted "--name=$prgname" --options=p:s: --longoptions=param:,stringparam: -- $@)

if  [ $? -ne 0 ]; then
    usage
    exit 1
fi

set -- $paralist
pp=""
ps=""
for option
    do case "$option" in
        -p|--param)       shift; pp="$pp $1"; shift;;
        -s|--stringparam) shift; ps="$ps $1"; shift;;
        --)               shift; break;;
    esac
done

xml="$1"; shift
if [ "$xml" = "" ]; then
    echo >&2 "$prgname: Missing input XML file"
    usage
    exit 1
fi

xsl="$1"; shift
if [ "$*" != '' ]; then
    echo >&2 "$prgname: Too many parameters"
    usage
    exit 1
fi

##echo "pp=$pp"
##echo "ps=$ps"
##echo "xml=$xml"
##echo "xsl=$xsl"

# if XSLTRANS environment variable is not set, we try to autodetect it
if [ "$XSLTRANS" = "" ]; then
    XSLTRANS=`which xsltproc`
    if [ "$XSLTRANS" = "" ]; then
        XSLTRANS=`which xmlstarlet`
        if [ "$XSLTRANS" = "" ]; then
            XSLTRANS=`which xalan`
            if [ "$XSLTRANS" = "" ]; then
                if [ -e /usr/share/java/xalan2.jar ]; then
                    XSLTRANS="/usr/share/java/xalan2.jar"
                fi
            fi
        fi
    fi
fi

if [ "$XSLTRANS" = "" ]; then
    echo >&2 "Can't find any XSL transformer on your system."
    echo >&2 "Please set the XSLTRANS environment variable to path of an XSL transformer."
    exit 2
fi

##echo "XSLTRANS=$XSLTRANS"

# We now have the XSL transformator we want to use in XSLTRANS

# If the transformator is a java .jar file, change the command to call java
command="$XSLTRANS"
if [[ "$command" =~ '\.jar$' ]]; then
    command="java -jar /usr/share/java/$XSLTRANS"
fi

##echo "command=$command"

xsltrans=`basename $XSLTRANS`

if [ "$xsltrans" = "xsltproc" ]; then
    pl=''
    for p in $pp; do
        k=${p%%=*}
        v=${p##*=}
        pl="$pl --param $k $v"
    done
    for p in $ps; do
        k=${p%%=*}
        v=${p##*=}
        pl="$pl --stringparam $k $v"
    done
    $command $pl $xsl $xml
elif [ "$xsltrans" = "xmlstarlet" ]; then
    if [ "$xsl" = '' ]; then
        echo >&2 "xmlstarlet doesn't work without explicit stylesheet"
        exit 4
    fi

    pl=''
    for p in $pp; do
        pl="$pl -p $p"
    done
    for p in $ps; do
        pl="$pl -s $p"
    done
    $command tr $xsl $pl $xml
elif [ "$xsltrans" = "xalan" ]; then
    pl=''
    for p in $pp; do
        k=${p%%=*}
        v=${p##*=}
        pl="$pl -param $k $v"
    done
    for p in $ps; do
        k=${p%%=*}
        v=${p##*=}
        pl="$pl -param $k '$v'"
    done
    if [ "$xsl" != '' ]; then
        xsl="-xsl $xsl"
    fi
    $command $pl -in $xml $xsl
elif [ "$xsltrans" = "xalan2.jar" ]; then
    pl=''
    for p in $pp; do
        k=${p%%=*}
        v=${p##*=}
        pl="$pl -PARAM $k $v"
    done
    for p in $ps; do
        k=${p%%=*}
        v=${p##*=}
        pl="$pl -PARAM $k $v"
    done
    if [ "$xsl" != '' ]; then
        xsl="-XSL $xsl"
    fi
    $command $pl -IN $xml $xsl
else
    echo >&2 "Unknown XSL transformator '$xsltrans'"
    exit 3
fi