/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Chatzilla.
 *
 * The Initial Developer of the Original Code is
 * New Dimensions Consulting, Inc.
 * Portions created by the Initial Developer are Copyright (C) 1999
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Robert Ginda, rginda@ndcico.com, original author
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

/*
 * This file is largely a ripoff of the chatzilla rdf.js file.  It could (and
 * probably should) be refactored into a more reusable library, and placed in
 * some global place (like utils.js)
 */

/*
 * The RDFHelper class wraps useful the RDFService and in-memory-datasource
 * into a single object making them generally easier to use, and defines
 * some RDF resources and literals that will be used throughout the app.
 * it also makes it wasy to debug RDF asserts, (by forwarding
 * RDFHelper.prototype.Assert() to RDFHelper.prototype.dAssert().)
 */

const RES_PFX = "http://www.mozilla.org/NC-xpcom#";

const nsIRDFResource = Components.interfaces.nsIRDFResource;
const nsIRDFNode = Components.interfaces.nsIRDFNode;
const nsIRDFLiteral = Components.interfaces.nsIRDFLiteral;

function RDFHelper()
{
    const RDF_MEMORYDS_CONTRACTID =
        "@mozilla.org/rdf/datasource;1?name=in-memory-datasource";
    const RDF_DS_IID = Components.interfaces.nsIRDFDataSource;

    const RDF_DS_CONTRACTID = "@mozilla.org/rdf/rdf-service;1";
    const RDF_SVC_IID = Components.interfaces.nsIRDFService;

    this.ds =
        Components.classes[RDF_MEMORYDS_CONTRACTID].createInstance(RDF_DS_IID);
    this.svc = 
        Components.classes[RDF_DS_CONTRACTID].getService(RDF_SVC_IID);    

    /* predefined nodes */
    this.resRoot = this.svc.GetResource ("NC:cview-data");
    this.resEmptyRoot = this.svc.GetResource ("NC:cview-data-empty");

    /* predefined arcs */
    this.resCmp       = this.svc.GetResource (RES_PFX + "component");
    this.resContractID    = this.svc.GetResource (RES_PFX + "contractid");
    this.resCLSID     = this.svc.GetResource (RES_PFX + "clsid");
    this.resIfc       = this.svc.GetResource (RES_PFX + "interface");
    this.resIName     = this.svc.GetResource (RES_PFX + "iname");
    this.resIID       = this.svc.GetResource (RES_PFX + "iid");
    this.resShow      = this.svc.GetResource (RES_PFX + "show");

    /* predefined literals */
    this.litTrue  = this.svc.GetLiteral ("true");
    this.litFalse = this.svc.GetLiteral ("false");

}

RDFHelper.prototype.GetResource =
function rdf_getr (s)
{
    return this.svc.GetResource(s);
}

RDFHelper.prototype.GetLiteral =
function rdf_getl (s)
{
    if (!s)
    {
        dd ("rdf_getl: no argument provided!");
        dd (getStackTrace());
        
        return "";
    }
    
    return this.svc.GetLiteral(s);
}

RDFHelper.prototype.Assert =
function rdf_assert (n1, a, n2, f)
{
    if (typeof f == "undefined")
        f = true;

//    return this.dAssert (n1, a, n2, f);
    return this.ds.Assert (n1, a, n2, f);
}

RDFHelper.prototype.Unassert =
function rdf_uassert (n1, a, n2)
{
    /*return this.dUnassert (n1, a, n2);*/
    return this.ds.Unassert (n1, a, n2);
}

RDFHelper.prototype.dAssert =
function rdf_dassert (n1, a, n2, f)
{
    var n1v = n1 ? n1.Value : "!!!";
    var av = a ? a.Value : "!!!";
    var n2v = n2 ? n2.Value : "!!!";
    
    if (!n1 || !a || !n2)
    {
        dd ("n1 " + n1v + " a " + av + " n2 " + n2v);
        dd(getStackTrace());
    }
    
    this.ds.Assert (n1, a, n2, f)
}

RDFHelper.prototype.dUnassert =
function rdf_duassert (n1, a, n2)
{

    var n1v = n1 ? n1.Value : "!!!";
    var av = a ? a.Value : "!!!";
    var n2v = n2 ? n2.Value : "!!!";
    
    if (!n1 || !a || !n2)
        dd(getStackTrace());
    
    this.ds.Unassert (n1, a, n2)

}

RDFHelper.prototype.Change =
function rdf_duassert (n1, a, n2)
{

    var oldN2 = this.ds.GetTarget (n1, a, true);
    if (!oldN2)
    {
        dd ("** Unable to change " + n1.Value + " -[" + a.Value + "]->, " +
            "because old value was not found.");
        return;
    }
    
    this.ds.Change (n1, a, oldN2, n2);
    
}

RDFHelper.prototype.GetTarget =
function rdf_gettarget (n1, a)
{
    return this.ds.GetTarget (n1, a, true);
}

RDFHelper.prototype.GetTargets =
function rdf_gettarget (n1, a)
{
    return this.ds.GetTargets (n1, a, true);
}

RDFHelper.prototype.clearTargets =
function rdf_inittree (n1, a, recurse)
{
    if (typeof recurse == "undefined")
        recurse = false;

    var targets = this.ds.GetTargets(n1, a, true);

    while (targets.hasMoreElements())
    {
        var n2 = targets.getNext().QueryInterface(nsIRDFNode);

        if (recurse)
        {
            try
            {
                var resN2 = n2.QueryInterface(nsIRDFResource);
                var arcs = this.ds.ArcLabelsOut(resN2);

                while (arcs.hasMoreElements())
                {
                    arc = arcs.getNext().QueryInterface(nsIRDFNode);
                    this.clearTargets (resN2, arc, true);
                }
            }
            catch (e)
            {
                /*
                dd ("** Caught " + e + " while recursivley clearing " +
                    n2.Value + " **");
                */
            }
        }
        
        this.Unassert (n1, a, n2);
    }
}    

RDFHelper.prototype.initTree =
function rdf_inittree (id)
{
    var tree = document.getElementById (id);
    tree.database.AddDataSource (this.ds);
}

RDFHelper.prototype.setTreeRoot =
function rdf_settroot (id, root)
{
    var tree = document.getElementById (id);

    if (typeof root == "object")
        root = root.Value;
    tree.setAttribute ("ref", root);
}

RDFHelper.prototype.getTreeRoot =
function rdf_gettroot (id, root)
{
    var tree = document.getElementById (id);

    return tree.getAttribute ("ref");
}