ValuePath.cs

﻿// Name:        ValuePath.cs
// Description: Definitions for encapsulating IfcReference instances
// Author:      Tim Chipman
// Origination: Work performed for BuildingSmart by Constructivity.com LLC.
// Copyright:   (c) 2013 BuildingSmart International Ltd.
// License:     http://www.buildingsmart-tech.org/legal

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Reflection;
using System.Text;

using IfcDoc.Schema;
using IfcDoc.Schema.DOC;

namespace IfcDoc
{

    /// <summary>
    /// Resolves attribute path expressions. 
    /// Used for importing or exporting data, constraining attributes, and approving attributes.
    /// </summary>
    public class CvtValuePath
    {
        DocDefinition m_type;
        DocAttribute m_property;
        string m_identifier; // identifier is specified
        bool m_vector; // query is for list, not single value
        CvtValuePath m_inner;

        /// <summary>
        /// Constructs a blank value path.
        /// </summary>
        public CvtValuePath()
        {
        }

        /// <summary>
        /// Constructs a value path with all parameters
        /// </summary>
        /// <param name="type"></param>
        /// <param name="property"></param>
        /// <param name="identifier"></param>
        /// <param name="inner"></param>
        public CvtValuePath(DocDefinition type, DocAttribute property, string identifier, CvtValuePath inner)
        {
            this.m_type = type;
            this.m_property = property;
            this.m_identifier = identifier;
            this.m_inner = inner;
        }

        internal static string GetParameterName(string syntax)
        {
            // quick check -- no escaping necessary as syntax is constrained
            if (syntax != null)
            {
                int iParamHead = syntax.IndexOf('@');
                if (iParamHead > 0)
                {
                    int iParamTail = syntax.IndexOf(']', iParamHead + 1);
                    if (iParamTail > iParamHead)
                    {
                        return syntax.Substring(iParamHead + 1, iParamTail - iParamHead - 1);
                    }
                }
            }

            return null;
        }

        /// <summary>
        /// Parses a value path from string in ISO-10303-11 (EXPRESS) format.
        /// </summary>
        /// <param name="value"></param>
        /// <returns></returns>
        public static CvtValuePath Parse(string value, Dictionary<string, DocObject> map)
        {
            if (value == null)
                return null;

            string[] tokens = value.Split(new char[] { '\\' }); //???// don't remove empty entries -- if it ends in backslash, then indicates type identifier

            CvtValuePath rootpath = null;
            CvtValuePath outerpath = null;
            foreach (string token in tokens)
            {
                CvtValuePath valuepath = new CvtValuePath();

                string[] parts = token.Split(new char[] { '.' }, StringSplitOptions.RemoveEmptyEntries);
                if (parts.Length >= 1 && map.ContainsKey(parts[0]))
                {
                    valuepath.Type = map[parts[0]] as DocDefinition;
                    if (valuepath.Type != null && parts.Length == 2)
                    {
                        string propname = parts[1];
                        int bracket = propname.IndexOf('[');
                        if (bracket >= 0)
                        {
                            string content = propname.Substring(bracket + 1, propname.Length - bracket - 2);
                            if (content.StartsWith("'") && content.EndsWith("'"))
                            {
                                // indexed by name                                
                                valuepath.Identifier = content.Substring(1, content.Length - 2);
                            }
                            else if (content.StartsWith("@"))
                            {
                                // indexed by parameter for each line, e.g. value identifies column by name when importing/exporting spreadsheet
                                valuepath.Identifier = content;
                            }
                            else if (content.Length == 0)
                            {
                                valuepath.Vector = true;
                            }

                            propname = propname.Substring(0, bracket);
                        }

                        if (valuepath.Type is DocEntity)
                        {
                            DocEntity docEntity = (DocEntity)valuepath.Type;
                            valuepath.Property = docEntity.ResolveAttribute(propname, map);
                        }
                    }

                }

                // chain
                if (outerpath != null)
                {
                    outerpath.InnerPath = valuepath;
                }
                else
                {
                    rootpath = valuepath;
                }

                outerpath = valuepath;
            }

            // avoid empty head link
            if (rootpath.Type == null && rootpath.Property == null && rootpath.InnerPath != null)
            {
                rootpath = rootpath.InnerPath;
            }

            return rootpath;
        }

        /// <summary>
        /// The type of object for which property applies, or NULL to indicate the type is defined by parameter.
        /// </summary>
        public DocDefinition Type
        {
            get
            {
                return this.m_type;
            }
            private set
            {
                this.m_type = value;
            }
        }

        /// <summary>
        /// The property to query, or NULL to indicate casting to specified type.
        /// </summary>
        public DocAttribute Property
        {
            get
            {
                return this.m_property;
            }
            private set
            {
                this.m_property = value;
            }
        }

        /// <summary>
        /// The identifier of an item within a collection by Name, or NULL to indicate any item in collection.
        /// </summary>
        public string Identifier
        {
            get
            {
                return this.m_identifier;
            }
            private set
            {
                this.m_identifier = value;
            }
        }

        /// <summary>
        /// True indicates query is for multiple items; False indicates single scalar item.
        /// </summary>
        public bool Vector
        {
            get
            {
                return this.m_vector;
            }
            private set
            {
                this.m_vector = value;
            }
        }

        /// <summary>
        /// The inner chain of path elements.
        /// </summary>
        public CvtValuePath InnerPath
        {
            get
            {
                return this.m_inner;
            }
            internal set
            {
                this.m_inner = value;
            }
        }

        /// <summary>
        /// Formats the value path into an expression.
        /// </summary>
        /// <returns></returns>
        public override string ToString()
        {
            StringBuilder sb = new StringBuilder();
            this.AppendString(sb);
            return sb.ToString();
        }

        /// <summary>
        /// Internal function for building expression string
        /// </summary>
        /// <param name="sb"></param>
        private void AppendString(StringBuilder sb)
        {
            sb.Append("\\");

            if (this.m_type == null)
            {
                // represents type query, so just backslash
                return;
            }

            sb.Append(this.m_type.Name);
            if (this.m_property == null)
            {
                // represents type cast, so return
                return;
            }

            sb.Append(".");
            sb.Append(this.m_property.Name);

            if (this.m_property.GetAggregation() != DocAggregationEnum.NONE)
            {
                sb.Append("[");
                if (!this.m_vector)
                {
                    if (this.m_identifier != null)
                    {
                        if (this.m_identifier.StartsWith("@"))
                        {
                            sb.Append(this.m_identifier); // @ is a reserved character indicating parameter substitution
                        }
                        else
                        {
                            sb.Append("'");
                            sb.Append(this.m_identifier);
                            sb.Append("'");
                        }
                    }
                    else
                    {
                        sb.Append("*");
                    }
                }
                sb.Append("]");
            }

            if (this.m_inner != null)
            {
                this.m_inner.AppendString(sb);
            }
        }

        /// <summary>
        /// Gets value referenced by path.
        /// </summary>
        /// <param name="target">The relative object to retrieve the value.</param>
        /// <param name="parameters">Optional parameters for substitution.</param>
        /// <returns>The value on the object along the expression path.</returns>
        public object GetValue(object target, Dictionary<string, object> parameters)
        {
            if (target == null)
                throw new ArgumentNullException("target");

            if (this.m_type == null)
            {
                return target.GetType();
            }

            if (!this.m_type.IsInstanceOfType(target))
                return null; // doesn't apply

            if (this.m_property == null)
            {
                return target; // for general case, if no attribute specified, then return object itself
            }

            object value = null;

            if (this.m_property.PropertyType != null && 
                this.m_property.PropertyType.IsGenericType &&
                typeof(System.Collections.IEnumerable).IsAssignableFrom(this.m_property.PropertyType) &&
                IsEntity(this.m_property.PropertyType))
               // (typeof(SEntity).IsAssignableFrom(this.m_property.PropertyType.GetGenericArguments()[0]) || this.m_property.PropertyType.GetGenericArguments()[0].IsInterface))
            {
                System.Collections.IEnumerable list = (System.Collections.IEnumerable)this.m_property.GetValue(target, null);

                // if expecting array, then return it.
                if (this.m_vector && (this.m_identifier == null && this.m_inner == null))
                {
                    return list;
                }
                else if (this.m_identifier != null && this.m_identifier.StartsWith("@") && parameters == null)
                {
                    // return filtered list based on expected type -- may be none if no compatible types -- e.g. COBie properties only return IfcPropertyEnumeratedValue
                    if (this.InnerPath != null && this.InnerPath.Type != null)
                    {
                        List<object> listFilter = null;
                        foreach (object ent in list)
                        {
                            if (this.InnerPath.Type.IsInstanceOfType(ent))
                            {
                                if (listFilter == null)
                                {
                                    listFilter = new List<object>();
                                }
                                listFilter.Add(ent);
                            }
                        }

                        return listFilter;
                    }
                    else
                    {
                        return list;
                    }
                }

                if (list != null)
                {
                    int listindex = 0; // identify by 1-based numeric index within list
                    if(!String.IsNullOrEmpty(this.m_identifier) && Int32.TryParse(this.m_identifier, out listindex) && listindex > 0 && list is System.Collections.IList)// && listindex <= list.Count)
                    {
                        System.Collections.IList listlist = (System.Collections.IList)list;
                        if (listindex <= listlist.Count)
                        {
                            object eachelem = listlist[listindex - 1];

                            if (this.m_inner != null && IsEntity(eachelem))
                            {
                                object eachvalue = this.m_inner.GetValue(eachelem, parameters);
                                if (eachvalue != null)
                                {
                                    return eachvalue;
                                }
                            }
                            else
                            {
                                return eachelem;
                            }                   
                        }
                    }

                    foreach (object eachelem in list)
                    {
                        // derived class may have its own specific property (e.g. IfcSIUnit, IfcConversionBasedUnit)
                        if (!String.IsNullOrEmpty(this.m_identifier))
                        {
                            Type eachtype = eachelem.GetType();

                            // special cases for properties and quantities
                            if (eachtype.Name.Equals("IfcRelDefinesByProperties"))
                            {
                                PropertyInfo fieldRelatingPropertyDefinition = eachtype.GetProperty("RelatingPropertyDefinition");
                                object ifcPropertySet = fieldRelatingPropertyDefinition.GetValue(eachelem);
                                if (ifcPropertySet != null)
                                {
                                    Type typePropertySet = ifcPropertySet.GetType();
                                    PropertyInfo fieldName = typePropertySet.GetProperty("Name");
                                    object ifcLabel = fieldName.GetValue(ifcPropertySet);
                                    if (ifcLabel != null)
                                    {
                                        PropertyInfo fieldValue = ifcLabel.GetType().GetProperty("Value");
                                        if (fieldValue != null)
                                        {
                                            string sval = fieldValue.GetValue(ifcLabel) as string;
                                            if (this.m_identifier.Equals(sval))
                                            {
                                                // matches!
                                                if (this.m_inner != null)
                                                {
                                                    object eachvalue = this.m_inner.GetValue(eachelem, parameters);
                                                    if (eachvalue != null)
                                                    {
                                                        return eachvalue;
                                                    }
                                                }
                                                else
                                                {
                                                    return eachelem;
                                                }

                                            }
                                        }
                                    }
                                }
                            }
                            else
                            {
                                // fall back on Name field for properties or quantities
                                PropertyInfo fieldName = eachtype.GetProperty("Name");
                                if (fieldName != null)
                                {
                                    object ifcLabel = fieldName.GetValue(eachelem);
                                    if (ifcLabel != null)
                                    {
                                        PropertyInfo fieldValue = ifcLabel.GetType().GetProperty("Value");
                                        if (fieldValue != null)
                                        {
                                            object ifcValue = fieldValue.GetValue(ifcLabel);
                                            while(fieldValue.PropertyType.IsValueType && !fieldValue.PropertyType.IsPrimitive)
                                            {
                                                fieldValue = fieldValue.PropertyType.GetProperty("Value");
                                                ifcValue = fieldValue.GetValue(ifcLabel);
                                            }

                                            string sval = ifcValue as string;
                                            if (this.m_identifier.Equals(sval))
                                            {
                                                // matches!
                                                if (this.m_inner != null)
                                                {
                                                    object eachvalue = this.m_inner.GetValue(eachelem, parameters);
                                                    if (eachvalue != null)
                                                    {
                                                        return eachvalue;
                                                    }
                                                }
                                                else
                                                {
                                                    return eachelem;
                                                }

                                            }
                                        }
                                    }
                                }
                            }
                        }
                        else
                        {
                            // use first non-null item within inner reference
                            if (this.m_inner != null && IsEntity(eachelem))
                            {
                                object eachvalue = this.m_inner.GetValue(eachelem, parameters);
                                if (eachvalue != null)
                                {
                                    return eachvalue;
                                }
                            }
                            else
                            {
                                return eachelem;
                            }
                        }
                    }

                    return null; // not found
                }


            }
            else if (this.m_inner != null)
            {
                value = this.m_property.GetValue(target, null);
                if (IsEntity(value))
                {
                    // hack for GSA
                    if(value.GetType().Name.Equals("IfcIrregularTimeSeries"))
                    {
                        return value;
                    }

                    value = this.m_inner.GetValue(value, parameters);

                    if (this.m_identifier != null && value != null)
                    {
                        // qualify the value
                        Type eachtype = value.GetType();
                        DefaultMemberAttribute[] attrs = (DefaultMemberAttribute[])eachtype.GetCustomAttributes(typeof(DefaultMemberAttribute), true);
                        PropertyInfo propElem = null;
                        if (attrs.Length > 0)
                        {
                            propElem = eachtype.GetProperty(attrs[0].MemberName);
                        }
                        else
                        {
                            propElem = eachtype.GetProperty("Name");
                        }

                        if (propElem != null)
                        {
                            object name = propElem.GetValue(value, null);
                            if (name == null || !this.m_identifier.Equals(name.ToString()))
                            {
                                return null;
                            }
                        }
                    }
                }
            }
            else
            {
                value = this.m_property.GetValue(target, null);
            }

            return value;
        }

        public static bool IsEntity(object obj)
        {
            if (obj == null)
                return false;

            if (obj is System.Collections.IEnumerable || obj is ValueType) // not a collection or a string or value type
                return false;

            return true; // class or interface
        }

        /// <summary>
        /// Extracts description of referenced data, using properties, quantities, and attributes.
        /// </summary>
        /// <param name="mapEntity"></param>
        /// <param name="docView">Optional model view, for retrieving more specific descriptions such as for ports</param>
        /// <returns></returns>
        public string GetDescription(Dictionary<string, DocObject> mapEntity, DocModelView docView)
        {
            string desc = null;
            CvtValuePath valpath = this;

            if (valpath != null &&
                valpath.Property != null &&
                valpath.Property.Name.Equals("IsDefinedBy") &&
                valpath.InnerPath != null && valpath.InnerPath.Type.Name.Equals("IfcRelDefinesByProperties") &&
                valpath.Identifier != null)
            {
                DocObject docPset = null;
                mapEntity.TryGetValue(valpath.Identifier, out docPset);

                if (docPset is DocPropertySet)
                {
                    DocProperty docProp = ((DocPropertySet)docPset).GetProperty(valpath.InnerPath.InnerPath.Identifier);
                    if (docProp != null)
                    {
                        desc = docProp.Documentation;// localize??

                        if (String.IsNullOrEmpty(docProp.Documentation))
                        {
                            this.ToString();
                        }
                    }
                }
                else if (docPset is DocQuantitySet)
                {
                    DocQuantity docProp = ((DocQuantitySet)docPset).GetQuantity(valpath.InnerPath.InnerPath.Identifier);
                    if (docProp != null)
                    {
                        desc = docProp.Documentation;// localize??

                        if(String.IsNullOrEmpty(docProp.Documentation))
                        {
                            this.ToString();
                        }
                    }
                }
            }
            else if (valpath != null &&
                valpath.Property != null &&
                valpath.Property.Name.Equals("HasAssignments") &&
                valpath.InnerPath != null && valpath.InnerPath.Type.Name.Equals("IfcRelAssignsToControl") &&
                valpath.InnerPath.InnerPath != null && valpath.InnerPath.InnerPath.Type.Name.Equals("IfcPerformanceHistory"))
            {
                DocObject docPset = null;
                if(mapEntity.TryGetValue(valpath.InnerPath.InnerPath.Identifier, out docPset))
                {
                    DocProperty docProp = ((DocPropertySet)docPset).GetProperty(valpath.InnerPath.InnerPath.InnerPath.InnerPath.Identifier);
                    if (docProp != null)
                    {
                        desc = docProp.Documentation;// localize??

                        if(docProp.Documentation == null)
                        {
                            DocLocalization docLoc = docProp.GetLocalization(null);
                            if(docLoc != null)
                            {
                                desc = docLoc.Documentation;
                            }
                        }
                    }
                }

                this.ToString();
            }
            else if (valpath != null &&
                valpath.Property != null &&
                valpath.Property.Name.Equals("HasPropertySets") &&
                valpath.InnerPath != null && valpath.InnerPath.Type.Name.Equals("IfcPropertySet"))
            {
                DocObject docPset = null;
                mapEntity.TryGetValue(valpath.Identifier, out docPset);

                if (docPset is DocPropertySet)
                {
                    DocProperty docProp = ((DocPropertySet)docPset).GetProperty(valpath.InnerPath.Identifier);
                    if (docProp != null)
                    {
                        desc = docProp.Documentation;// localize??

                        if(String.IsNullOrEmpty(docProp.Documentation))
                        {
                            this.ToString();
                        }
                    }
                }
            }
            else if(valpath != null &&
                valpath.Property != null &&
                valpath.Property.Name.Equals("Material") &&
                valpath.InnerPath != null && valpath.InnerPath.Type.Name.Equals("IfcMaterial") &&
                valpath.InnerPath.InnerPath != null && valpath.InnerPath.InnerPath.Type.Name.Equals("IfcMaterialProperties"))
            {
                DocObject docPset = null;
                mapEntity.TryGetValue(valpath.InnerPath.Identifier, out docPset);

                if(docPset is DocPropertySet)
                {
                    DocProperty docProp = ((DocPropertySet)docPset).GetProperty(valpath.InnerPath.InnerPath.Identifier);
                    if(docProp != null)
                    {
                        desc = docProp.Documentation;
                    }
                }
            }
            else if (valpath != null &&
                valpath.Property != null &&
                valpath.Property.Name.Equals("HasProperties") &&
                valpath.InnerPath != null && valpath.InnerPath.Type.Name.Equals("IfcMaterialProperties"))
            {
                DocObject docPset = null;
                mapEntity.TryGetValue(valpath.Identifier, out docPset);

                if (docPset is DocPropertySet)
                {
                    DocProperty docProp = ((DocPropertySet)docPset).GetProperty(valpath.InnerPath.Identifier);
                    if (docProp != null)
                    {
                        desc = docProp.Documentation;
                    }
                }
            }
            else if (valpath != null && 
                valpath.Property != null &&
                valpath.Property.Name.Equals("IsNestedBy") &&
                valpath.InnerPath != null && valpath.InnerPath.InnerPath != null && valpath.InnerPath.InnerPath != null)
            {
                CvtValuePath pathInner = valpath.InnerPath.InnerPath;
                if (pathInner.Type != null && pathInner.Type.Name.Equals("IfcDistributionPort"))
                {
                    string portname = valpath.InnerPath.Identifier;
                    if (pathInner.Property != null && pathInner.Property.Name.Equals("IsDefinedBy"))
                    {
                        // lookup description of property at port
                        DocObject docPset = null;
                        mapEntity.TryGetValue(pathInner.Identifier, out docPset);

                        if (docPset is DocPropertySet)
                        {
                            DocProperty docProp = ((DocPropertySet)docPset).GetProperty(pathInner.InnerPath.InnerPath.Identifier);
                            if (docProp != null)
                            {
                                desc = portname + ": " + docProp.Documentation;
                            }
                        }

                    }
                    else
                    {
                        desc = portname;

                        // lookup description of port
                        Guid guidPortNesting = new Guid("bafc93b7-d0e2-42d8-84cf-5da20ee1480a");
                        if (docView != null)
                        {
                            foreach (DocConceptRoot docRoot in docView.ConceptRoots)
                            {
                                if (docRoot.ApplicableEntity == valpath.Type)
                                {
                                    foreach (DocTemplateUsage docConcept in docRoot.Concepts)
                                    {
                                        if (docConcept.Definition != null && docConcept.Definition.Uuid == guidPortNesting)
                                        {
                                            foreach (DocTemplateItem docItem in docConcept.Items)
                                            {
                                                if (docItem.Name != null && docItem.Name.Equals(portname))
                                                {
                                                    desc = docItem.Documentation;
                                                    break;
                                                }
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }

            if (desc == null)
            {
                while (valpath != null && valpath.InnerPath != null && valpath.InnerPath.Property != null)
                {
                    valpath = valpath.InnerPath;
                }
                if (valpath != null && valpath.Property != null)
                {
                    desc = valpath.Property.Documentation;
                }
                else if (valpath != null)
                {
                    desc = "The IFC class identifier indicating the subtype of object.";
                }
            }

            // clear out any notes
            int block = desc.IndexOf("<blockquote");
            if(block != -1)
            {
                desc = desc.Substring(0, block);
            }

            return desc;
        }

        public static CvtValuePath FromTemplateDefinition(DocTemplateDefinition dtd, DocProject docProject)
        {
            if (dtd.Rules.Count > 0 && dtd.Rules[0] is DocModelRuleAttribute)
            {
                DocModelRuleAttribute docRuleAtt = (DocModelRuleAttribute)dtd.Rules[0];

                DocEntity docEnt = docProject.GetDefinition(dtd.Type) as DocEntity;
                if (docEnt != null)
                {
                    CvtValuePath pathInner = null;
                    if (docRuleAtt.Rules.Count > 0 && docRuleAtt.Rules[0] is DocModelRuleEntity)
                    {
                        pathInner = FromModelRule((DocModelRuleEntity)docRuleAtt.Rules[0], docProject);
                    }

                    DocAttribute docAtt = docEnt.ResolveAttribute(docRuleAtt.Name, docProject);
                    string identifier = null;

                    if (docRuleAtt.Name.Equals("IsDefinedBy"))
                    {
                        // hack for compat
                        docRuleAtt.ToString();

                        // look for identifier
                        if (docRuleAtt.Rules.Count > 0)
                        {
                            try
                            {
                                DocModelRuleConstraint docRuleIndexCon = (DocModelRuleConstraint)docRuleAtt.Rules[0].Rules[0].Rules[0].Rules[1].Rules[0].Rules[0];

                                if (docRuleIndexCon != null)
                                {
                                    if (docRuleIndexCon.Expression is DocOpStatement)
                                    {
                                        DocOpStatement docOpStatement = (DocOpStatement)docRuleIndexCon.Expression;
                                        if (docOpStatement.Value != null)
                                        {
                                            identifier = docOpStatement.Value.ToString();
                                            if (identifier.StartsWith("'") && identifier.EndsWith("'"))
                                            {
                                                identifier = identifier.Substring(1, identifier.Length - 2);
                                            }
                                        }
                                    }
                                }
                            }
                            catch
                            {

                            }
                        }
                    }

                    CvtValuePath pathRoot = new CvtValuePath(docEnt, docAtt, identifier, pathInner);
                    return pathRoot;
                }
            }

            return null;
        }

        private static CvtValuePath FromModelRule(DocModelRuleEntity docRuleEntity, DocProject docProject)
        {
            DocDefinition docDef = docProject.GetDefinition(docRuleEntity.Name);
            DocAttribute docAtt = null;
            string identifier = null;
            CvtValuePath pathInner = null;

            if (docDef is DocEntity && docRuleEntity.Rules.Count > 0 && docRuleEntity.Rules[0] is DocModelRuleAttribute)
            {
                DocModelRuleAttribute docRuleAtt = (DocModelRuleAttribute)docRuleEntity.Rules[0];
                DocEntity docEnt = (DocEntity)docDef;
                docAtt = docEnt.ResolveAttribute(docRuleAtt.Name, docProject);

                if (docRuleAtt.Rules.Count > 0 && docRuleAtt.Rules[0] is DocModelRuleEntity)
                {
                    DocModelRuleEntity docRuleInner = (DocModelRuleEntity)docRuleAtt.Rules[0];
                    pathInner = FromModelRule(docRuleInner, docProject);


                    // look for identifier
                    if (docRuleInner.Rules.Count > 1 && docRuleInner.Rules[1] is DocModelRuleAttribute)
                    {
                        DocModelRuleAttribute docRuleIndexAtt = (DocModelRuleAttribute)docRuleInner.Rules[1];
                        if (docRuleIndexAtt.Rules.Count > 0)
                        {
                            DocModelRuleEntity docRuleIndexEnt = (DocModelRuleEntity)docRuleIndexAtt.Rules[0];
                            if (docRuleIndexEnt.Rules.Count > 0 && docRuleIndexEnt.Rules[0] is DocModelRuleConstraint)
                            {
                                DocModelRuleConstraint docRuleIndexCon = (DocModelRuleConstraint)docRuleIndexEnt.Rules[0];
                                if (docRuleIndexCon.Expression is DocOpStatement)
                                {
                                    DocOpStatement docOpStatement = (DocOpStatement)docRuleIndexCon.Expression;
                                    if (docOpStatement.Value != null)
                                    {
                                        identifier = docOpStatement.Value.ToString();
                                        if (identifier.StartsWith("'") && identifier.EndsWith("'"))
                                        {
                                            identifier = identifier.Substring(1, identifier.Length - 2);
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }

            CvtValuePath pathOuter = new CvtValuePath(docDef, docAtt, identifier, pathInner);
            return pathOuter;
        }

        public DocTemplateDefinition ToTemplateDefinition()
        {
            DocTemplateDefinition docTemplate = new DocTemplateDefinition();
            DocModelRuleEntity docRule = this.ToModelRule();
            if (docRule != null && docRule.Rules.Count > 0 && docRule.Rules[0] is DocModelRuleAttribute)
            {
                DocModelRuleAttribute docRuleAttr = (DocModelRuleAttribute)docRule.Rules[0];

                docTemplate.Type = docRule.Name;
                docTemplate.Rules.Add(docRuleAttr);
                docRuleAttr.ParentRule = null;
            }
            return docTemplate;
        }

        private DocModelRuleEntity ToModelRule()
        {
            if (this.Type == null)
                return null;

            DocModelRuleEntity docRuleEntity = new DocModelRuleEntity();
            docRuleEntity.Name = this.Type.Name;

            if (this.Property != null)
            {
                DocModelRuleAttribute docRuleAttr = new DocModelRuleAttribute();
                docRuleAttr.Name = this.Property.Name;
                docRuleEntity.Rules.Add(docRuleAttr);
                docRuleAttr.ParentRule = docRuleEntity;

                if (this.InnerPath != null)
                {
                    DocModelRuleEntity docInner = this.InnerPath.ToModelRule();
                    if (docInner != null)
                    {
                        docRuleAttr.Rules.Add(docInner);
                        docInner.ParentRule = docRuleAttr;
                    }

                    if (this.Identifier != null)
                    {
                        // traverse to the default attribute

                        DocModelRuleEntity docApplicableRule = docInner;
                        if (this.InnerPath.Type.Name.Equals("IfcRelDefinesByProperties"))
                        {
                            // hack for back compat
                            DocModelRuleAttribute docPsetAttr = docInner.Rules[0] as DocModelRuleAttribute;
                            DocModelRuleEntity docPsetEnt = docPsetAttr.Rules[0] as DocModelRuleEntity;

                            docApplicableRule = docPsetEnt;
                        }
                        
                        DocModelRuleAttribute docWhereAttr = new DocModelRuleAttribute();
                        docWhereAttr.Name = "Name";//... dynamically check...
                        docApplicableRule.Rules.Add(docWhereAttr);
                        docWhereAttr.ParentRule = docApplicableRule;

                        DocModelRuleEntity docWhereEnt = new DocModelRuleEntity();
                        docWhereEnt.Name = "IfcLabel";//... dynamically check...
                        docWhereAttr.Rules.Add(docWhereEnt);
                        docWhereEnt.ParentRule = docWhereAttr;

                        DocModelRuleConstraint docRuleConstraint = new DocModelRuleConstraint();

                        // general case
                        docWhereEnt.Rules.Add(docRuleConstraint);
                        docRuleConstraint.ParentRule = docWhereEnt;
                        

                        DocOpLiteral oplit = new DocOpLiteral();
                        oplit.Operation = DocOpCode.LoadString;
                        oplit.Literal = this.Identifier;

                        DocOpStatement op = new DocOpStatement();
                        op.Operation = DocOpCode.CompareEqual;
                        op.Value = oplit;

                        DocOpReference opref = new DocOpReference();
                        opref.Operation = DocOpCode.NoOperation; // ldfld...
                        opref.EntityRule = docWhereEnt;
                        op.Reference = opref;

                        docRuleConstraint.Expression = op;
                    }
                }

            }


            return docRuleEntity;
        }
    }


}