/* ========================================================================
 * Copyright (c) 2005-2019 The OPC Foundation, Inc. All rights reserved.
 *
 * OPC Foundation MIT License 1.00
 * 
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 * 
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * The complete license agreement can be found here:
 * http://opcfoundation.org/License/MIT/1.00/
 * ======================================================================*/

using System;
using System.Text;
using System.Collections.Generic;
using Opc.Ua;
using Opc.Ua.Client;

namespace OpcUaHelper
{
    /// <summary>
    /// Stores a type declaration retrieved from a server.
    /// </summary>
    public class TypeDeclaration
    {
        /// <summary>
        /// The node if for the type.
        /// </summary>
        public NodeId NodeId;

        /// <summary>
        /// The fully inhierited list of instance declarations for the type.
        /// </summary>
        public List<InstanceDeclaration> Declarations;
    }

    /// <summary>
    /// Stores an instance declaration fetched from the server.
    /// </summary>
    public class InstanceDeclaration
    {
        /// <summary>
        /// The type that the declaration belongs to.
        /// </summary>
        public NodeId RootTypeId;

        /// <summary>
        /// The browse path to the instance declaration.
        /// </summary>
        public QualifiedNameCollection BrowsePath;

        /// <summary>
        /// The browse path to the instance declaration.
        /// </summary>
        public string BrowsePathDisplayText;

        /// <summary>
        /// A localized path to the instance declaration.
        /// </summary>
        public string DisplayPath;

        /// <summary>
        /// The node id for the instance declaration.
        /// </summary>
        public NodeId NodeId;

        /// <summary>
        /// The node class of the instance declaration.
        /// </summary>
        public NodeClass NodeClass;

        /// <summary>
        /// The browse name for the instance declaration.
        /// </summary>
        public QualifiedName BrowseName;

        /// <summary>
        /// The display name for the instance declaration.
        /// </summary>
        public string DisplayName;

        /// <summary>
        /// The description for the instance declaration.
        /// </summary>
        public string Description;

        /// <summary>
        /// The modelling rule for the instance declaration (i.e. Mandatory or Optional).
        /// </summary>
        public NodeId ModellingRule;

        /// <summary>
        /// The data type for the instance declaration.
        /// </summary>
        public NodeId DataType;

        /// <summary>
        /// The value rank for the instance declaration.
        /// </summary>
        public int ValueRank;

        /// <summary>
        /// The built-in type parent for the data type.
        /// </summary>
        public BuiltInType BuiltInType;

        /// <summary>
        /// A localized name for the data type.
        /// </summary>
        public string DataTypeDisplayText;

        /// <summary>
        /// An instance declaration that has been overridden by the current instance.
        /// </summary>
        public InstanceDeclaration OverriddenDeclaration;
    }

    /// <summary>
    /// A field in a filter declaration.
    /// </summary>
    public class FilterDeclarationField
    {
        /// <summary>
        /// Creates a new instance of a FilterDeclarationField.
        /// </summary>
        public FilterDeclarationField()
        {
            Selected = true;
            DisplayInList = false;
            FilterEnabled = false;
            FilterOperator = FilterOperator.Equals;
            FilterValue = Variant.Null;
            InstanceDeclaration = null;
        }

        /// <summary>
        /// Creates a new instance of a FilterDeclarationField.
        /// </summary>
        public FilterDeclarationField( InstanceDeclaration instanceDeclaration )
        {
            Selected = true;
            DisplayInList = false;
            FilterEnabled = false;
            FilterOperator = FilterOperator.Equals;
            FilterValue = Variant.Null;
            InstanceDeclaration = instanceDeclaration;
        }

        /// <summary>
        /// Creates a new instance of a FilterDeclarationField.
        /// </summary>
        public FilterDeclarationField( FilterDeclarationField field )
        {
            Selected = field.Selected;
            DisplayInList = field.DisplayInList;
            FilterEnabled = field.FilterEnabled;
            FilterOperator = field.FilterOperator;
            FilterValue = field.FilterValue;
            InstanceDeclaration = field.InstanceDeclaration;
        }

        /// <summary>
        /// Whether the field is returned as part of the event notification.
        /// </summary>
        public bool Selected;

        /// <summary>
        /// Whether the field is displayed in the list view.
        /// </summary>
        public bool DisplayInList;

        /// <summary>
        /// Whether the filter is enabled.
        /// </summary>
        public bool FilterEnabled;

        /// <summary>
        /// The filter operator to use in the where clause.
        /// </summary>
        public FilterOperator FilterOperator;

        /// <summary>
        /// The filter value to use in the where clause.
        /// </summary>
        public Variant FilterValue;

        /// <summary>
        /// The instance declaration associated with the field.
        /// </summary>
        public InstanceDeclaration InstanceDeclaration;
    }

    /// <summary>
    /// A declararion of an event filter.
    /// </summary>
    public class FilterDeclaration
    {
        /// <summary>
        /// Creates a new instance of a FilterDeclaration.
        /// </summary>
        public FilterDeclaration()
        {
            EventTypeId = Opc.Ua.ObjectTypeIds.BaseEventType;
            Fields = new List<FilterDeclarationField>( );
        }

        /// <summary>
        /// Creates a new instance of a FilterDeclaration.
        /// </summary>
        public FilterDeclaration( TypeDeclaration eventType, FilterDeclaration template )
        {
            EventTypeId = eventType.NodeId;
            Fields = new List<FilterDeclarationField>( );

            foreach (InstanceDeclaration instanceDeclaration in eventType.Declarations)
            {
                if (instanceDeclaration.NodeClass == NodeClass.Method)
                {
                    continue;
                }

                if (NodeId.IsNull( instanceDeclaration.ModellingRule ))
                {
                    continue;
                }

                FilterDeclarationField element = new FilterDeclarationField( instanceDeclaration );
                Fields.Add( element );

                // set reasonable defaults.
                if (template == null)
                {
                    if (instanceDeclaration.RootTypeId == Opc.Ua.ObjectTypeIds.BaseEventType && instanceDeclaration.BrowseName != Opc.Ua.BrowseNames.EventId)
                    {
                        element.DisplayInList = true;
                    }
                }

                // preserve filter settings.
                else
                {
                    foreach (FilterDeclarationField field in template.Fields)
                    {
                        if (field.InstanceDeclaration.BrowsePathDisplayText == element.InstanceDeclaration.BrowsePathDisplayText)
                        {
                            element.DisplayInList = field.DisplayInList;
                            element.FilterEnabled = field.FilterEnabled;
                            element.FilterOperator = field.FilterOperator;
                            element.FilterValue = field.FilterValue;
                            break;
                        }
                    }
                }
            }
        }

        /// <summary>
        /// Creates a new instance of a FilterDeclaration.
        /// </summary>
        public FilterDeclaration( FilterDeclaration declaration )
        {
            EventTypeId = declaration.EventTypeId;
            Fields = new List<FilterDeclarationField>( declaration.Fields.Count );

            for (int ii = 0; ii < declaration.Fields.Count; ii++)
            {
                Fields.Add( new FilterDeclarationField( declaration.Fields[ii] ) );
            }
        }

        /// <summary>
        /// Returns the event filter defined by the filter declaration.
        /// </summary>
        public EventFilter GetFilter()
        {
            EventFilter filter = new EventFilter( );
            filter.SelectClauses = GetSelectClause( );
            filter.WhereClause = GetWhereClause( );
            return filter;
        }

        /// <summary>
        /// Adds a simple field to the declaration.
        /// </summary>
        public void AddSimpleField( QualifiedName browseName, BuiltInType dataType, bool displayInList )
        {
            AddSimpleField( new QualifiedName[] { browseName }, NodeClass.Variable, dataType, ValueRanks.Scalar, displayInList );
        }

        /// <summary>
        /// Adds a simple field to the declaration.
        /// </summary>
        public void AddSimpleField( QualifiedName browseName, BuiltInType dataType, int valueRank, bool displayInList )
        {
            AddSimpleField( new QualifiedName[] { browseName }, NodeClass.Variable, dataType, valueRank, displayInList );
        }

        /// <summary>
        /// Adds a simple field to the declaration.
        /// </summary>
        public void AddSimpleField( QualifiedName[] browseNames, BuiltInType dataType, int valueRank, bool displayInList )
        {
            AddSimpleField( browseNames, NodeClass.Variable, dataType, valueRank, displayInList );
        }

        /// <summary>
        /// Adds a simple field to the declaration.
        /// </summary>
        public void AddSimpleField( QualifiedName[] browseNames, NodeClass nodeClass, BuiltInType dataType, int valueRank, bool displayInList )
        {
            FilterDeclarationField field = new FilterDeclarationField( );

            field.DisplayInList = displayInList;
            field.InstanceDeclaration = new InstanceDeclaration( );
            field.InstanceDeclaration.NodeClass = nodeClass;

            if (browseNames != null)
            {
                field.InstanceDeclaration.BrowseName = browseNames[browseNames.Length - 1];
                field.InstanceDeclaration.BrowsePath = new QualifiedNameCollection( );

                StringBuilder path = new StringBuilder( );

                for (int ii = 0; ii < browseNames.Length; ii++)
                {
                    if (path.Length > 0)
                    {
                        path.Append( '/' );
                    }

                    path.Append( browseNames[ii] );
                    field.InstanceDeclaration.BrowsePath.Add( browseNames[ii] );
                }

                field.InstanceDeclaration.BrowsePathDisplayText = path.ToString( );
            }

            field.InstanceDeclaration.BuiltInType = dataType;
            field.InstanceDeclaration.DataType = (uint)dataType;
            field.InstanceDeclaration.ValueRank = valueRank;
            field.InstanceDeclaration.DataTypeDisplayText = dataType.ToString( );

            if (valueRank >= 0)
            {
                field.InstanceDeclaration.DataTypeDisplayText += "[]";
            }

            field.InstanceDeclaration.DisplayName = field.InstanceDeclaration.BrowseName.Name;
            field.InstanceDeclaration.DisplayPath = field.InstanceDeclaration.BrowsePathDisplayText;
            field.InstanceDeclaration.RootTypeId = ObjectTypeIds.BaseEventType;
            Fields.Add( field );
        }

        /// <summary>
        /// Returns the select clause defined by the filter declaration.
        /// </summary>
        public SimpleAttributeOperandCollection GetSelectClause()
        {
            SimpleAttributeOperandCollection selectClause = new SimpleAttributeOperandCollection( );

            SimpleAttributeOperand operand = new SimpleAttributeOperand( );
            operand.TypeDefinitionId = Opc.Ua.ObjectTypeIds.BaseEventType;
            operand.AttributeId = Attributes.NodeId;
            selectClause.Add( operand );

            foreach (FilterDeclarationField field in Fields)
            {
                if (field.Selected)
                {
                    operand = new SimpleAttributeOperand( );
                    operand.TypeDefinitionId = field.InstanceDeclaration.RootTypeId;
                    operand.AttributeId = (field.InstanceDeclaration.NodeClass == NodeClass.Object) ? Attributes.NodeId : Attributes.Value;
                    operand.BrowsePath = field.InstanceDeclaration.BrowsePath;
                    selectClause.Add( operand );
                }
            }

            return selectClause;
        }

        /// <summary>
        /// Returns the where clause defined by the filter declaration.
        /// </summary>
        public ContentFilter GetWhereClause()
        {
            ContentFilter whereClause = new ContentFilter( );
            ContentFilterElement element1 = whereClause.Push( FilterOperator.OfType, EventTypeId );

            EventFilter filter = new EventFilter( );

            foreach (FilterDeclarationField field in Fields)
            {
                if (field.FilterEnabled)
                {
                    SimpleAttributeOperand operand1 = new SimpleAttributeOperand( );
                    operand1.TypeDefinitionId = field.InstanceDeclaration.RootTypeId;
                    operand1.AttributeId = (field.InstanceDeclaration.NodeClass == NodeClass.Object) ? Attributes.NodeId : Attributes.Value;
                    operand1.BrowsePath = field.InstanceDeclaration.BrowsePath;

                    LiteralOperand operand2 = new LiteralOperand( );
                    operand2.Value = field.FilterValue;

                    ContentFilterElement element2 = whereClause.Push( field.FilterOperator, operand1, operand2 );
                    element1 = whereClause.Push( FilterOperator.And, element1, element2 );
                }
            }

            return whereClause;
        }

        /// <summary>
        /// Returns the value for the specified browse name.
        /// </summary>
        public T GetValue<T>( QualifiedName browseName, VariantCollection fields, T defaultValue )
        {
            if (fields == null || fields.Count == 0)
            {
                return defaultValue;
            }

            if (browseName == null)
            {
                browseName = QualifiedName.Null;
            }

            for (int ii = 0; ii < this.Fields.Count; ii++)
            {
                if (this.Fields[ii].InstanceDeclaration.BrowseName == browseName)
                {
                    if (ii >= fields.Count + 1)
                    {
                        return defaultValue;
                    }

                    object value = fields[ii + 1].Value;

                    if (typeof( T ).IsInstanceOfType( value ))
                    {
                        return (T)value;
                    }

                    break;
                }
            }

            return defaultValue;
        }

        /// <summary>
        /// The type of event.
        /// </summary>
        public NodeId EventTypeId;

        /// <summary>
        /// The list of declarations for the fields.
        /// </summary>
        public List<FilterDeclarationField> Fields;
    }
}