// A very basic XML Parser written in  LSL.

// global variables for reading, holding, and handling the initial XML read
string xmlFileName = "xml-test";
string xmlBody = "";
integer xmlBodyLine = 0;
key xmlBodyKey;

// Chops off the string up to the first, found element
// xml - XML string
// start - where the llSubStringIndex begins
// offset - the length to the right the substring needs to begin
string llReadTo(string xml, integer start, integer offset)
{
    integer ReadTo = start + offset;
    return llGetSubString(xml, ReadTo, -1);    
}

// Returns the inner text of a node.
string llGetNodeText(string xml, string nodeName)
{
    string elStart = "<" + nodeName;
    string elStop = "</" + nodeName + ">";
    
    integer elCloseTag = llSubStringIndex(xml, elStop);
    integer elOpenTag = llSubStringIndex(xml, "/>");
    
    // There has to be some kind of closing tag for the parsing to be valid
    if (elCloseTag != -1 || elOpenTag != -1)
    {       
        // For: <tag> ... </tag>    
        if (llSubStringIndex(xml, elStart) != -1 &&
            (elCloseTag < elOpenTag || elOpenTag == -1))
        {
            integer nodeStart = llSubStringIndex(xml, elStart) + llStringLength(elStart) + 1;
            integer nodeStop = llSubStringIndex(xml, elStop) - 1;
            string nodeText = llGetSubString(xml, nodeStart, nodeStop);
            return nodeText;
        }

        // For: <tag/>
        else if (llSubStringIndex(xml, elStart) != -1 &&
                 (elCloseTag > elOpenTag || elCloseTag == -1))
        {
            integer nodeStart = llSubStringIndex(xml, elStart) + llStringLength(elStart) + 1;
            integer nodeStop = llSubStringIndex(xml, "/>") - 1;
            string nodeText = llGetSubString(xml, nodeStart, nodeStop);    
            return nodeText;        
        }
        
        // For: invalid XML
        else
        {
            return "";
        }
    }
    
    else
    {
        return "";
    }
}

// Counts the number of nodes in a string
integer llCountElements(string xml, string nodeName)
{
    string elStart = "<" + nodeName;
    integer elStartLen = llStringLength(elStart) + 1;
    integer nodeCount = 0;
    
    while (llSubStringIndex(xml, elStart) != -1)
    {
        // Increments node count
        ++nodeCount;
        
        // Chops off the string up to the first, found element
        xml = llReadTo(xml, llSubStringIndex(xml, elStart), elStartLen);
    }
    
    return nodeCount;   
}

// Checks for attributes in an element
list llGetElementAttributes(string xml)
{
    integer elTagEnd = 0;
    
    if (llSubStringIndex(xml, "/>") == -1)
    {
        elTagEnd = llSubStringIndex(xml, ">") - 1;
    }
    else
    {
        if (llSubStringIndex(xml, " />") == -1)
        {
            elTagEnd = llSubStringIndex(xml, "/>") - 1;
        }
        else
        {
            elTagEnd = llSubStringIndex(xml, "/>") - 2;
        }
    }
    
    xml = llGetSubString(xml, 0, elTagEnd);
    
    list attributes = llParseString2List(xml, ["=\"", "\""], []);
    
    return attributes;
}

// Gets an attribute value, based of an attribute's name, from  apaired list
string llGetAttributeValue(list attributes, string name)
{
    string value = "";
    integer isName = 0;
    integer isCntr = 0;
    
    // isName is switched to 1 when the loop finds a list valuen with the attribute name
    // in the next iteration, the next list value is assigned to the variable "value"
    // and isName is reset to 0
    while (llList2String(attributes, isCntr) != "")
    {
        if (isName == 1)
        {
            value = llList2String(attributes, isCntr);
            
            isName = 0;
        }
        
        else
        {
            if ((isCntr % 2) == 0)
            {
                string temp = llList2String(attributes, isCntr);
                
                if (llGetSubString(temp, 0, 0) == " ")
                {
                    temp = llGetSubString(temp, 1, -1);
                }
                
                if (temp == name)
                {
                    isName = 1;
                }
            }
        }
        
        isCntr++;
    }
    
    return value;
}

// Gets a list of nodes
list llGetNodeList(string xml, string nodeName)
{
    list nodeList;
    integer elementCount = llCountElements(xml, nodeName);

    // If nodes exist with the XML string, proceed    
    if (elementCount > 0)
    {
        integer nodeCntr;
        
        for (nodeCntr = 0; nodeCntr < elementCount; nodeCntr++)
        {
            string tempText = llGetNodeText(xml, nodeName);
            
            nodeList = nodeList + [tempText];
            
            xml = llReadTo(xml, llSubStringIndex(xml, tempText), llStringLength(tempText));
            xml = llGetSubString(xml, llSubStringIndex(xml, "<" + nodeName), -1);

        }
    }
    
    // If there are no such nodes in the string, return a one element
    // list with "No nodes" inside.
    else
    {
        nodeList = ["No nodes"];
    }
    
    return nodeList;
}

// This has to be here
default
{
    state_entry()
    {
        if (xmlBody == "")
        {
            state readfile;
        }
        
        else
        {
            llSay(0, xmlBody);
        }
    }

    touch_start(integer total_number)
    {
        list spies = llGetNodeList(xmlBody, "spy");
        integer spyCntr = 0;
        
        while (llList2String(spies, spyCntr) != "")
        {
            string xmlTemp = llList2String(spies, spyCntr);

            list spyName = llGetElementAttributes(xmlTemp);
            
            string hairSpy = llGetAttributeValue(spyName, "hair");
            string lenSpy = llGetAttributeValue(spyName, "length");
            string nameSpy = llGetAttributeValue(spyName, "name");
                                
            string color = llGetNodeText(xmlTemp, "suit");

            llSay(0, nameSpy + " has a " + color + " uniform and " + lenSpy + ", " + hairSpy + " hair.");
            
            ++spyCntr;
        }
    }
}

// This simply reads XML from a Notecard.
// This can be removed when grabbing information from the web.
state readfile
{
    state_entry()
    {
        // Makes sure xmlBody is empty
        xmlBody = "";
        
        // Starts the reading of the notecard
        xmlBodyKey = llGetNotecardLine(xmlFileName, xmlBodyLine);
    }
    
    dataserver(key query_id, string data)
    {
        if (query_id == xmlBodyKey)
        {
            // Perform the following while there is text
            if (data != EOF)
            {
                // Removes leading spaces or tabs
                if (llSubStringIndex(data, "<") > 0)
                {
                    data = llDeleteSubString(data, 0, (llSubStringIndex(data, "<") - 1));
                }
                
                // Appends the next line to xmlBody
                xmlBody = xmlBody + data;
                
                // Increments the line counter
                ++xmlBodyLine;
                
                // Reads the next line
                xmlBodyKey = llGetNotecardLine(xmlFileName, xmlBodyLine);
            }
            
            // If you've gotten to the end of the notecard, go back
            else
            {
                state default;
            }
            
        }
    }
    
    state_exit()
    {
        xmlBodyLine = 0;
    }
}