// This function converts simple column constraints
// into a filter that can be applied to a VOTABLE XML document
//
// T.McGlynn 9/12/2007

function xslt(indices, constraints, types) {

    var xsl1='<?xml version="1.0" encoding="UTF-8"?>\n' +
            '<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"\n' +
            'xmlns:vo="http://www.ivoa.net/xml/VOTable/v1.1"\n' +
            'xmlns:v1="http://vizier.u-strasbg.fr/VOTable"\n' +
            'xmlns:v2="http://vizier.u-strasbg.fr/xml/VOTable-1.1.xsd"\n' +
            'xmlns:v3="http://www.ivoa.net/xml/VOTable/v1.0"\n' +
            'exclude-result-prefixes="vo v1 v2 v3" version="1.0">\n' +
            '<xsl:variable name="lc" select="\'abcdefghijklmnopqrstuvwxyz\'" />\n' +
            '<xsl:variable name="uc" select="\'ABCDEFGHIJKLMNOPQRSTUVWXYZ\'" />\n' +
            '<xsl:variable name="allRows" select="//TR|//vo:TR|//v1:TR|//v2:TR|//v3:TR" />\n';

    var xsl2='<xsl:template match="TABLE|vo:TABLE|v1:TABLE|v2:TABLE|v3:TABLE">\n' +
            '<PARAM datatype="int" name="VOV:TotalCount" value="{count($allRows)}" />\n' +
            '<PARAM datatype="int" name="VOV:FilterCount" value="{count($filterRows)}" />\n' +
            '<xsl:copy>\n' +
            '<xsl:apply-templates />\n' +
            '</xsl:copy>\n' +
            '</xsl:template>\n' +
            '<xsl:template match="TABLEDATA|vo:TABLEDATA|v1:TABLEDATA|v2:TABLEDATA|v3:TABLEDATA">\n' +
            '<xsl:copy>\n' +
            '<xsl:for-each select="$filterRows">\n' +
            '<xsl:copy>\n' +
            '<xsl:apply-templates />\n' +
            '</xsl:copy>\n' +
            '</xsl:for-each>\n' +
            '</xsl:copy>\n' +
            '</xsl:template>\n' +
            '<xsl:template match="@*|node()">\n' +
            '<xsl:copy>\n' +
            '<xsl:apply-templates select="@*|node()"/>\n' +
            '</xsl:copy>\n' +
            '</xsl:template>\n' +
            '</xsl:stylesheet>\n';

    if (indices.length > 0) {
        var all = new Array();
        for (var i=0; i<indices.length; i += 1) {
            var con = makeXSLConstraint(indices[i], constraints[i], types[i]);
            if (con != null) {
                all.push(con);
            }
        }
        if (all.length) {
            var full = all.join(" and ");
            var xslgen = '<xsl:variable name="filterRows" select="$allRows['+full+']" />\n';
            return xsl1+xslgen+xsl2;
        } else {
            return null;
        }
    } else {
        return null;
    }
}

// Convert a single constraint into appropriate XSLT filter elements.
function makeXSLConstraint(index, constraint, isChar) {
    if (constraint.length == 0) {
        return null;
    }
    if (constraint.substring(0,1) == '=') {
        constraint = constraint.substring(1);
    }
    if (constraint.length == 0) {
        return null;
    }
    if (isChar) {
        return charConstraint(index, constraint);
    } else {
        return numConstraint(index, constraint);
    }
}

// Handle a constraint on a character column
function charConstraint(index, constraint) {
    constraint = constraint.toUpperCase();
    if (constraint.indexOf('*') >= 0 ) {
        return wildCardConstraint(index, constraint);
    } else {
        return stdCharConstraint(index, constraint);
    }
}
   
function wildCardConstraint(index, constraint) {

    var initial = false;
    var ffinal  = false;

    if (constraint.substring(0,1) == "*") {
        initial = true;
        constraint = constraint.substring(1);
    }
    if (constraint.substring(constraint.length-1) == '*') {
        ffinal = true;
        constraint = constraint.substring(0,constraint.length-1);
    }

    if (constraint.length == 0) {
        return null;
    }
    var fields = constraint.split('\*');
    var out    = new Array();

    out.push("position() = "+index);

    for (var i=0; i<fields.length; i += 1) {
        if (i == 0 && !initial) {
            out.push("starts-with(translate(normalize-space(string()), $lc, $uc),'" + fields[i] + "')");
            
        } else if (i == fields.length-1 && !ffinal) {
            out.push("contains(translate(normalize-space(string()), $lc, $uc),'"+fields[i]+"')");
            out.push("string-length(substring-after(translate(normalize-space(string()), $lc, $uc),'"+fields[i]+"'))=0");
            
        } else {
            out.push("contains(translate(string(), $lc, $uc), '"   + fields[i] + "')");
        }
        if (i > 0) {
            out.push("string-length(substring-after(translate(string(), $lc, $uc), '"  +fields[i]   + "')) &lt; " +
                     "string-length(substring-after(translate(string(), $lc, $uc), '" + fields[i-1] + "'))");
        }
    }
    return "(TD|vo:TD|v1:TD|v2:TD|v3:TD)[" + out.join(" and ") + "]" ;
}

function stdCharConstraint(index, constraint) {
    constraint = trim(constraint);
    return "translate(normalize-space((TD|vo:TD|v1:TD|v2:TD|v3:TD)["+index+"]), $lc, $uc)='"+constraint+"'";
//    return "(TD|vo:TD|v1:TD|v2:TD|v3:TD)[position()="+index+" and translate(normalize-space(value()), $lc, $uc)='"+constraint+"']";
}


function rangeConstraint(index, constraint) {

    var fields=constraint.split("\.\.", 2);
    if (fields[0].length == 0 || fields[1].length == 0) {
        return null;
    }
    var con =  "(TD|vo:TD|v1:TD|v2:TD|v3:TD)["+index+"] &gt;=" +fields[0]+" and "+
               "(TD|vo:TD|v1:TD|v2:TD|v3:TD)["+index+"] &lt;=" +fields[1]+"";
    return con;
}

function numConstraint(index, constraint) {

    if (constraint.indexOf("..") > 0) {
        return rangeConstraint(index, constraint);

    } else {
        if (constraint.substring(0,1) == ">" ) {
            constraint = constraint.replace(">", "&gt;");
        } else if (constraint.substring(0,1) == "<" ) {
            constraint = constraint.replace("<", "&lt;");
        } else if (constraint.substring(0,1) != "=") {
            constraint = "=" + constraint;
        } 
        constraint = "(TD|vo:TD|v1:TD|v2:TD|v3:TD)["+index+"]"+constraint;
        return constraint;
    }
}