//---------------------------------------------------------------------
// <copyright file="StorageEntityContainerMapping.cs" company="Microsoft">
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
//
// @owner       Microsoft
// @backupOwner Microsoft
//---------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Xml;
using System.Data.Metadata.Edm;
using System.Diagnostics;
using System.Data.Mapping.ViewGeneration;
using System.Data.Common.Utils;
using System.Data.Mapping.ViewGeneration.Structures;
using System.Data.Mapping.ViewGeneration.Validation;

namespace System.Data.Mapping {

    using CellGroup = Set<Cell>;

    /// <summary>
    /// Represents the Mapping metadata for the EntityContainer map in CS space.
    /// Only one EntityContainerMapping element is allowed in the MSL file for CS mapping.
    /// <example>
    /// For Example if conceptually you could represent the CS MSL file as following
    /// ---Mapping 
    ///    --EntityContainerMapping ( CNorthwind-->SNorthwind )
    ///      --EntitySetMapping
    ///      --AssociationSetMapping 
    /// The type represents the metadata for EntityContainerMapping element in the above example.
    /// The SetMapping elements that are children of the EntityContainerMapping element
    /// can be accessed through the properties on this type.
    /// </example>
    /// <remarks>
    /// We currently assume that an Entity Container on the C side
    /// is mapped to a single Entity Container in the S - space.
    /// </remarks>
    /// </summary>
    internal class StorageEntityContainerMapping : Map
 {
        #region Constructors
        /// <summary>
        /// Construct a new EntityContainer mapping object 
        /// passing in the C-space EntityContainer  and
        /// the s-space Entity container metadata objects.
        /// </summary>
        /// <param name="entityContainer">Entity Continer type that is being mapped on the C-side</param>
        /// <param name="storageEntityContainer">Entity Continer type that is being mapped on the S-side</param>
        internal StorageEntityContainerMapping(EntityContainer entityContainer, EntityContainer storageEntityContainer, StorageMappingItemCollection storageMappingItemCollection, bool validate, bool generateUpdateViews)
        {
            this.m_entityContainer = entityContainer;
            this.m_storageEntityContainer = storageEntityContainer;
            this.m_storageMappingItemCollection = storageMappingItemCollection;
            this.m_memoizedCellGroupEvaluator = new Memoizer<InputForComputingCellGroups, OutputFromComputeCellGroups>(ComputeCellGroups, new InputForComputingCellGroups());
            this.identity = entityContainer.Identity;
            this.m_validate = validate;
            this.m_generateUpdateViews = generateUpdateViews;
        }
        #endregion

        #region Fields
        private string identity;
        private bool m_validate;
        private bool m_generateUpdateViews;
        private EntityContainer m_entityContainer;  //Entity Continer type that is being mapped on the C-side
        private EntityContainer m_storageEntityContainer;  //Entity Continer type that the C-space container is being mapped to
        private Dictionary<string, StorageSetMapping> m_entitySetMappings = new Dictionary<string, StorageSetMapping>(StringComparer.Ordinal);  //A collection of EntitySetMappings under this EntityContainer mapping
        private Dictionary<string, StorageSetMapping> m_associationSetMappings = new Dictionary<string, StorageSetMapping>(StringComparer.Ordinal);  //A collection of AssociationSetMappings under this EntityContainer mapping        
        private Dictionary<EdmFunction, FunctionImportMapping> m_functionImportMappings = new Dictionary<EdmFunction, FunctionImportMapping>();
        private string m_sourceLocation; //Schema URI for the mapping
        private int m_startLineNumber; //Line Number for EntityContainer Mapping element start tag
        private int m_startLinePosition; //Line position for EntityContainer Mapping element start tag
        private readonly StorageMappingItemCollection m_storageMappingItemCollection;
        private readonly Memoizer<InputForComputingCellGroups, OutputFromComputeCellGroups> m_memoizedCellGroupEvaluator;

        #endregion

        #region Properties
        public StorageMappingItemCollection StorageMappingItemCollection
        {
            get
            {
                return m_storageMappingItemCollection;
            }
        }

        /// <summary>
        /// Gets the type kind for this item
        /// </summary>
        public override BuiltInTypeKind BuiltInTypeKind {
            get { return BuiltInTypeKind.MetadataItem; }
        }

        /// <summary>
        /// The Entity Container Metadata object on the C-side
        /// for which the mapping is being represented.
        /// </summary>
        internal override MetadataItem EdmItem {
            get {
                return this.m_entityContainer;
            }
        }

        internal override string Identity {
            get {
                return identity;
            }
        }

        /// <summary>
        /// Indicates whether there are no Set mappings
        /// in the container mapping.
        /// </summary>
        internal bool IsEmpty
        {
            get
            {
                return ((m_entitySetMappings.Count == 0)
                && (m_associationSetMappings.Count == 0));
            }
        }

        /// <summary>
        /// Determine whether the container includes any views.
        /// Returns true if there is at least one query or update view specified by the mapping.
        /// </summary>
        internal bool HasViews
        {
            get
            {
                return HasMappingFragments()
                    || AllSetMaps.Any((StorageSetMapping setMap) => setMap.QueryView != null);
            }
        }


        internal string SourceLocation {
            get { return m_sourceLocation; }
            set { m_sourceLocation = value; }
        }

        /// <summary>
        /// The Entity Container Metadata object on the C-side
        /// for which the mapping is being represented.
        /// </summary>
        internal EntityContainer EdmEntityContainer {
            get {
                return this.m_entityContainer;
            }
        }

        /// <summary>
        /// The Entity Container Metadata object on the C-side
        /// for which the mapping is being represented.
        /// </summary>
        internal EntityContainer StorageEntityContainer {
            get {
                return this.m_storageEntityContainer;
            }
        }

        /// <summary>
        /// a list of all the  entity set maps under this
        /// container. In CS mapping, the mapping is done
        /// at the extent level as opposed to the type level.
        /// </summary>
        internal ReadOnlyCollection<StorageSetMapping> EntitySetMaps {
            get {
                return new List<StorageSetMapping>(this.m_entitySetMappings.Values).AsReadOnly();
            }
        }

        /// <summary>
        /// a list of all the  entity set maps under this
        /// container. In CS mapping, the mapping is done
        /// at the extent level as opposed to the type level.
        /// RelationshipSetMaps will be CompositionSetMaps and
        /// AssociationSetMaps put together.
        /// </summary>
        /// <remarks>
        /// The reason we have RelationshipSetMaps is to be consistent with CDM metadata
        /// which treats both associations and compositions as Relationships.
        /// </remarks>
        internal ReadOnlyCollection<StorageSetMapping> RelationshipSetMaps {
            get {
                return new List<StorageSetMapping>(this.m_associationSetMappings.Values).AsReadOnly();
            }
        }

        /// <summary>
        /// a list of all the  set maps under this
        /// container. 
        /// </summary>
        internal IEnumerable<StorageSetMapping> AllSetMaps
        {
            get
            {
                return System.Linq.Enumerable.Concat(this.m_entitySetMappings.Values, this.m_associationSetMappings.Values);
            }
        }

        /// <summary>
        /// Line Number in MSL file where the EntityContainer Mapping Element's Start Tag is present.
        /// </summary>
        internal int StartLineNumber
        {
            get
            {
                return m_startLineNumber;
            }
            set
            {
                m_startLineNumber = value;
            }
        }

        /// <summary>
        /// Line Position in MSL file where the EntityContainer Mapping Element's Start Tag is present.
        /// </summary>
        internal int StartLinePosition
        {
            get
            {
                return m_startLinePosition;
            }
            set
            {
                m_startLinePosition = value;
            }
        }

        /// <summary>
        /// Indicates whether to validate the mapping or not.
        /// </summary>
        internal bool Validate
        {
            get
            {
                return m_validate;
            }
        }

        /// <summary>
        /// Indicates whether to generate the update views or not.
        /// </summary>
        internal bool GenerateUpdateViews
        {
            get
            {
                return m_generateUpdateViews;
            }
        }
        #endregion

        #region Methods
        /// <summary>
        /// get an EntitySet mapping based upon the name of the entity set.
        /// </summary>
        /// /// <param name="entitySetName">the name of the entity set</param>
        internal StorageSetMapping GetEntitySetMapping(String entitySetName) {
            EntityUtil.CheckArgumentNull(entitySetName, "entitySetName");
            //Key for EntitySetMapping should be EntitySet name and Entoty type name
            StorageSetMapping setMapping = null;
            m_entitySetMappings.TryGetValue(entitySetName, out setMapping);
            return setMapping;
        }

        /// <summary>
        /// Get a RelationShip set mapping based upon the name of the relationship set
        /// </summary>
        /// <param name="relationshipSetName">the name of the relationship set</param>
        /// <returns>the mapping for the entity set if it exists, null if it does not exist</returns>
        internal StorageSetMapping GetRelationshipSetMapping(string relationshipSetName) {
            EntityUtil.CheckArgumentNull(relationshipSetName, "relationshipSetName");
            StorageSetMapping setMapping = null;
            m_associationSetMappings.TryGetValue(relationshipSetName, out setMapping);
            return setMapping;
        }

        /// <summary>
        /// Get a RelationShipSet mapping that has the passed in EntitySet as one of the ends and is mapped to the
        /// table.
        /// </summary>
        internal IEnumerable<StorageAssociationSetMapping> GetRelationshipSetMappingsFor(EntitySetBase edmEntitySet, EntitySetBase storeEntitySet )
        {
            //First select the association set maps that are mapped to this table
            IEnumerable<StorageAssociationSetMapping> associationSetMappings = m_associationSetMappings.Values.Cast<StorageAssociationSetMapping>().Where(w => ((w.StoreEntitySet != null) && (w.StoreEntitySet == storeEntitySet)));
            //From this again filter the ones that have the specified EntitySet on atleast one end
            associationSetMappings = associationSetMappings.Where(associationSetMap => ((associationSetMap.Set as AssociationSet).AssociationSetEnds.Any(associationSetEnd => associationSetEnd.EntitySet == edmEntitySet)));
            return associationSetMappings;
        }


        /// <summary>
        /// Get a set mapping based upon the name of the set
        /// </summary>
        /// <param name="setName"></param>
        /// <returns></returns>
        internal StorageSetMapping GetSetMapping(string setName)
        {
            StorageSetMapping setMap = GetEntitySetMapping(setName);
            if (setMap == null)
            {
                setMap = GetRelationshipSetMapping(setName);
            }
            return setMap;
        }


        /// <summary>
        /// Adds an entity set mapping to the list of EntitySetMaps
        /// under this entity container mapping. The method will be called
        /// by the Mapping loader.
        /// </summary>
        internal void AddEntitySetMapping(StorageSetMapping setMapping) {
            if (!this.m_entitySetMappings.ContainsKey(setMapping.Set.Name))
                this.m_entitySetMappings.Add(setMapping.Set.Name, setMapping);
        }

        /// <summary>
        /// Adds a association set mapping to the list of AssociationSetMaps
        /// under this entity container mapping. The method will be called
        /// by the Mapping loader.
        /// </summary>
        internal void AddAssociationSetMapping(StorageSetMapping setMapping) {
            this.m_associationSetMappings.Add(setMapping.Set.Name, setMapping);
        }

        /// <summary>
        /// check whether the EntityContainerMapping contains
        /// the map for the given AssociationSet
        /// </summary>
        /// <param name="associationSet"></param>
        /// <returns></returns>
        internal bool ContainsAssociationSetMapping(AssociationSet associationSet) {
            return this.m_associationSetMappings.ContainsKey(associationSet.Name);
        }

        /// <summary>
        /// Returns whether the Set Map for the given set has a query view or not
        /// </summary>
        /// <param name="setName"></param>
        /// <returns></returns>
        internal bool HasQueryViewForSetMap(string setName)
        {            
            StorageSetMapping set = GetSetMapping(setName);
            if (set != null)
            {
                return (set.QueryView != null);
            }
            return false;
        }

        internal bool HasMappingFragments()
        {
            foreach (var extentMap in this.AllSetMaps)
            {
                foreach (var typeMap in extentMap.TypeMappings)
                {
                    if (typeMap.MappingFragments.Count > 0)
                    {
                        return true;
                    }
                }
            }
            return false;
        }

        ///<summary>
        /// The method builds up the spaces required for pretty printing each 
        /// part of the mapping.
        ///</summary>
        internal static string GetPrettyPrintString(ref int index) {

            string spaces = "";
            spaces = spaces.PadLeft(index, ' ');
            Console.WriteLine(spaces + "|");
            Console.WriteLine(spaces + "|");
            index++;
            spaces = spaces.PadLeft(index, ' ');
            Console.Write(spaces + "-");
            index++;
            spaces = spaces.PadLeft(index, ' ');
            Console.Write("-");
            index++;
            spaces = spaces.PadLeft(index, ' ');
            return spaces;
        }

        /// <summary>
        /// This method is primarily for debugging purposes.
        /// Will be removed shortly.
        /// </summary>
        /// <param name="index"></param>
        internal void Print(int index) {
            string spaces = "";
            StringBuilder sb = new StringBuilder();
            sb.Append(spaces);
            sb.Append("EntityContainerMapping");
            sb.Append("   ");
            sb.Append("Name:");
            sb.Append(this.m_entityContainer.Name);
            sb.Append("   ");
            Console.WriteLine(sb.ToString());
            foreach (StorageSetMapping extentMapping in m_entitySetMappings.Values) {
                extentMapping.Print(index + 5);
            }
            foreach (StorageSetMapping extentMapping in m_associationSetMappings.Values) {
                extentMapping.Print(index + 5);
            }
        }

        // Methods to modify and access function imports, which association a "functionImport" declared
        // in the model entity container with a targetFunction declared in the target
        internal void AddFunctionImportMapping(EdmFunction functionImport, FunctionImportMapping mapping)
        {
            m_functionImportMappings.Add(functionImport, mapping);
        }

        internal bool TryGetFunctionImportMapping(EdmFunction functionImport, out FunctionImportMapping mapping)
        {
            return m_functionImportMappings.TryGetValue(functionImport, out mapping);
        }

        internal OutputFromComputeCellGroups GetCellgroups(InputForComputingCellGroups args)
        { 
            Debug.Assert(object.ReferenceEquals(this, args.ContainerMapping));
            return m_memoizedCellGroupEvaluator.Evaluate(args);
        }

        private OutputFromComputeCellGroups ComputeCellGroups(InputForComputingCellGroups args)
        {
            OutputFromComputeCellGroups result = new OutputFromComputeCellGroups();
            result.Success = true;

            CellCreator cellCreator = new CellCreator(args.ContainerMapping);
            result.Cells = cellCreator.GenerateCells(args.Config);
            result.Identifiers = cellCreator.Identifiers;

            if (result.Cells.Count <= 0)
            {
                //When type-specific QVs are asked for but not defined in the MSL we should return without generating
                // Query pipeline will handle this appropriately by asking for UNION ALL view.
                result.Success = false;
                return result;
            }

            result.ForeignKeyConstraints = ForeignConstraint.GetForeignConstraints(args.ContainerMapping.StorageEntityContainer);

            // Go through each table and determine their foreign key constraints
            CellPartitioner partitioner = new CellPartitioner(result.Cells, result.ForeignKeyConstraints);
            List<CellGroup> cellGroups = partitioner.GroupRelatedCells();

            //Clone cell groups- i.e, List<Set<Cell>> - upto cell before storing it in the cache because viewgen modified the Cell structure
            result.CellGroups = cellGroups.Select(setOfcells => new CellGroup(setOfcells.Select(cell => new Cell(cell)))).ToList();

            return result;
        }

        #endregion
    }

    internal struct InputForComputingCellGroups : IEquatable<InputForComputingCellGroups>, IEqualityComparer<InputForComputingCellGroups>
    {
        internal readonly StorageEntityContainerMapping ContainerMapping;
        internal readonly ConfigViewGenerator Config;

        internal InputForComputingCellGroups(StorageEntityContainerMapping containerMapping, ConfigViewGenerator config)
        {
            this.ContainerMapping = containerMapping;
            this.Config = config;
        }

        public bool Equals(InputForComputingCellGroups other)
        {
            // Isn't this funny? We are not using Memoizer for function memoization. Args Entity and Config don't matter!
            // If I were to compare Entity this would not use the cache for cases when I supply different entity set. However,
            // the cell groups belong to ALL entity sets.
            return (this.ContainerMapping.Equals(other.ContainerMapping) 
                && this.Config.Equals(other.Config));
        }

        public bool Equals(InputForComputingCellGroups one, InputForComputingCellGroups two)
        {
            if (object.ReferenceEquals(one, two))
            {
                return true;
            }
            if (object.ReferenceEquals(one, null) || object.ReferenceEquals(two, null))
            {
                return false;
            }

            return one.Equals(two);
        }

        public int GetHashCode(InputForComputingCellGroups value)
        {
            if (value == null)
            {
                return 0;
            }

            return value.GetHashCode();
        }

        public override int GetHashCode()
        {
            return this.ContainerMapping.GetHashCode();
        }

        public override bool Equals(object obj)
        {
            if (obj is InputForComputingCellGroups)
            {
                return Equals((InputForComputingCellGroups)obj);
            }
            else
            {
                return false;
            }
        }

        public static bool operator ==(InputForComputingCellGroups input1, InputForComputingCellGroups input2)
        {
            if (object.ReferenceEquals(input1, input2))
            {
                return true;
            }
            return input1.Equals(input2);
        }

        public static bool operator !=(InputForComputingCellGroups input1, InputForComputingCellGroups input2)
        {
            return !(input1 == input2);
        }

    }

    internal struct OutputFromComputeCellGroups
    {
        internal List<Cell> Cells;
        internal CqlIdentifiers Identifiers;
        internal List<CellGroup> CellGroups;
        internal List<ForeignConstraint> ForeignKeyConstraints;
        internal bool Success;
    }
}