//---------------------------------------------------------------------
// <copyright file="EntityDataReader.cs" company="Microsoft">
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
//
// @owner  Microsoft
// @backupOwner Microsoft
//---------------------------------------------------------------------

namespace System.Data.EntityClient
{
    using System;
    using System.Collections;
    using System.ComponentModel;
    using System.Data;
    using System.Data.Common;
    using System.Diagnostics;

    /// <summary>
    /// A data reader class for the entity client provider
    /// </summary>
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1710:IdentifiersShouldHaveCorrectSuffix")]
    public class EntityDataReader : DbDataReader, IExtendedDataRecord
    {
        // The command object that owns this reader
        private EntityCommand _command;

        private CommandBehavior _behavior;

        // Store data reader, _storeExtendedDataRecord points to the same reader as _storeDataReader, it's here to just
        // save the casting wherever it's used
        private DbDataReader _storeDataReader;
        private IExtendedDataRecord _storeExtendedDataRecord;

        /// <summary>
        /// The constructor for the data reader, each EntityDataReader must always be associated with a EntityCommand and an underlying
        /// DbDataReader.  It is expected that EntityDataReader only has a reference to EntityCommand and doesn't assume responsibility
        /// of cleaning the command object, but it does assume responsibility of cleaning up the store data reader object.
        /// </summary>
        internal EntityDataReader(EntityCommand command, DbDataReader storeDataReader, CommandBehavior behavior)
            : base()
        {
            Debug.Assert(command != null && storeDataReader != null);

            this._command = command;
            this._storeDataReader = storeDataReader;
            this._storeExtendedDataRecord = storeDataReader as IExtendedDataRecord;
            this._behavior = behavior;
        }

        /// <summary>
        /// Get the depth of nesting for the current row
        /// </summary>
        public override int Depth
        {
            get
            {
                return this._storeDataReader.Depth;
            }
        }

        /// <summary>
        /// Get the number of columns in the current row
        /// </summary>
        public override int FieldCount
        {
            get
            {
                return this._storeDataReader.FieldCount;
            }
        }

        /// <summary>
        /// Get whether the data reader has any rows
        /// </summary>
        public override bool HasRows
        {
            get
            {
                return this._storeDataReader.HasRows;
            }
        }

        /// <summary>
        /// Get whether the data reader has been closed
        /// </summary>
        public override bool IsClosed
        {
            get
            {
                return this._storeDataReader.IsClosed;
            }
        }

        /// <summary>
        /// Get whether the data reader has any rows
        /// </summary>
        public override int RecordsAffected
        {
            get
            {
                return this._storeDataReader.RecordsAffected;
            }
        }

        /// <summary>
        /// Get the value of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the value</param>
        public override object this[int ordinal]
        {
            get
            {
                return this._storeDataReader[ordinal];
            }
        }

        /// <summary>
        /// Get the value of a column with the given name
        /// </summary>
        /// <param name="name">The name of the column to retrieve the value</param>
        public override object this[string name]
        {
            get
            {
                EntityUtil.CheckArgumentNull(name, "name");
                return this._storeDataReader[name];
            }
        }

        /// <summary>
        /// Get the number of non-hidden fields in the reader
        /// </summary>
        public override int VisibleFieldCount
        {
            get
            {
                return this._storeDataReader.VisibleFieldCount;
            }
        }

        /// <summary>
        /// DataRecordInfo property describing the contents of the record.
        /// </summary>
        public DataRecordInfo DataRecordInfo
        {
            get
            {
                if (null == this._storeExtendedDataRecord)
                {
                    // if a command has no results (e.g. FunctionImport with no return type),
                    // there is nothing to report.
                    return null;
                }
                return this._storeExtendedDataRecord.DataRecordInfo;
            }
        }

        /// <summary>
        /// Close this data reader
        /// </summary>
        public override void Close()
        {
            if (this._command != null)
            {
                this._storeDataReader.Close();

                // Notify the command object that we are closing, so clean up operations such as copying output parameters can be done
                this._command.NotifyDataReaderClosing();
                if ((this._behavior & CommandBehavior.CloseConnection) == CommandBehavior.CloseConnection)
                {
                    Debug.Assert(this._command.Connection != null);
                    this._command.Connection.Close();
                }
                this._command = null;
            }
        }

        /// <summary>
        /// Releases the resources used by this data reader 
        /// </summary>
        /// <param name="disposing">true to release both managed and unmanaged resources, false to release only unmanaged resources</param>
        protected override void Dispose(bool disposing)
        {
            base.Dispose(disposing);
            if (disposing)
            {
                this._storeDataReader.Dispose();
            }
        }

        /// <summary>
        /// Get the boolean value of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the value</param>
        /// <returns>The boolean value</returns>
        public override bool GetBoolean(int ordinal)
        {
            return this._storeDataReader.GetBoolean(ordinal);
        }

        /// <summary>
        /// Get the byte value of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the value</param>
        /// <returns>The byte value</returns>
        public override byte GetByte(int ordinal)
        {
            return this._storeDataReader.GetByte(ordinal);
        }

        /// <summary>
        /// Get the byte array value of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the value</param>
        /// <param name="dataOffset">The index within the row to start reading</param>
        /// <param name="buffer">The buffer to copy into</param>
        /// <param name="bufferOffset">The index in the buffer indicating where the data is copied into</param>
        /// <param name="length">The maximum number of bytes to read</param>
        /// <returns>The actual number of bytes read</returns>
        public override long GetBytes(int ordinal, long dataOffset, byte[] buffer, int bufferOffset, int length)
        {
            return this._storeDataReader.GetBytes(ordinal, dataOffset, buffer, bufferOffset, length);
        }

        /// <summary>
        /// Get the char value of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the value</param>
        /// <returns>The char value</returns>
        public override char GetChar(int ordinal)
        {
            return this._storeDataReader.GetChar(ordinal);
        }

        /// <summary>
        /// Get the char array value of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the value</param>
        /// <param name="dataOffset">The index within the row to start reading</param>
        /// <param name="buffer">The buffer to copy into</param>
        /// <param name="bufferOffset">The index in the buffer indicating where the data is copied into</param>
        /// <param name="length">The maximum number of bytes to read</param>
        /// <returns>The actual number of characters read</returns>
        public override long GetChars(int ordinal, long dataOffset, char[] buffer, int bufferOffset, int length)
        {
            return this._storeDataReader.GetChars(ordinal, dataOffset, buffer, bufferOffset, length);
        }

        /// <summary>
        /// Get the name of the data type of the column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the name of the data type</param>
        /// <returns>The name of the data type of the column</returns>
        public override string GetDataTypeName(int ordinal)
        {
            return this._storeDataReader.GetDataTypeName(ordinal);
        }

        /// <summary>
        /// Get the datetime value of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the value</param>
        /// <returns>The datetime value</returns>
        public override DateTime GetDateTime(int ordinal)
        {
            return this._storeDataReader.GetDateTime(ordinal);
        }

        /// <summary>
        /// Get the data reader of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the reader</param>
        /// <returns>The data reader</returns>
        protected override DbDataReader GetDbDataReader(int ordinal)
        {
            return this._storeDataReader.GetData(ordinal);
        }

        /// <summary>
        /// Get the decimal value of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the value</param>
        /// <returns>The decimal value</returns>
        public override decimal GetDecimal(int ordinal)
        {
            return this._storeDataReader.GetDecimal(ordinal);
        }

        /// <summary>
        /// Get the double value of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the value</param>
        /// <returns>The double value</returns>
        public override double GetDouble(int ordinal)
        {
            return this._storeDataReader.GetDouble(ordinal);
        }

        /// <summary>
        /// Get the data type of the column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the data type</param>
        /// <returns>The data type of the column</returns>
        public override Type GetFieldType(int ordinal)
        {
            return this._storeDataReader.GetFieldType(ordinal);
        }

        /// <summary>
        /// Get the float value of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the value</param>
        /// <returns>The float value</returns>
        public override float GetFloat(int ordinal)
        {
            return this._storeDataReader.GetFloat(ordinal);
        }

        /// <summary>
        /// Get the guid value of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the value</param>
        /// <returns>The guid value</returns>
        public override Guid GetGuid(int ordinal)
        {
            return this._storeDataReader.GetGuid(ordinal);
        }

        /// <summary>
        /// Get the int16 value of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the value</param>
        /// <returns>The int16 value</returns>
        public override short GetInt16(int ordinal)
        {
            return this._storeDataReader.GetInt16(ordinal);
        }

        /// <summary>
        /// Get the int32 value of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the value</param>
        /// <returns>The int32 value</returns>
        public override int GetInt32(int ordinal)
        {
            return this._storeDataReader.GetInt32(ordinal);
        }

        /// <summary>
        /// Get the int64 value of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the value</param>
        /// <returns>The int64 value</returns>
        public override long GetInt64(int ordinal)
        {
            return this._storeDataReader.GetInt64(ordinal);
        }

        /// <summary>
        /// Get the name of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the name</param>
        /// <returns>The name</returns>
        public override string GetName(int ordinal)
        {
            return this._storeDataReader.GetName(ordinal);
        }

        /// <summary>
        /// Get the ordinal of a column with the given name
        /// </summary>
        /// <param name="name">The name of the column to retrieve the ordinal</param>
        /// <returns>The ordinal of the column</returns>
        public override int GetOrdinal(string name)
        {
            EntityUtil.CheckArgumentNull(name, "name");
            return this._storeDataReader.GetOrdinal(name);
        }

        /// <summary>
        /// implementation for DbDataReader.GetProviderSpecificFieldType() method
        /// </summary>
        /// <param name="ordinal"></param>
        /// <returns></returns>
        [EditorBrowsableAttribute(EditorBrowsableState.Never)]
        override public Type GetProviderSpecificFieldType(int ordinal)
        {
            return _storeDataReader.GetProviderSpecificFieldType(ordinal);
        }

        /// <summary>
        /// implementation for DbDataReader.GetProviderSpecificValue() method
        /// </summary>
        /// <param name="ordinal"></param>
        /// <returns></returns>
        [EditorBrowsableAttribute(EditorBrowsableState.Never)]
        public override object GetProviderSpecificValue(int ordinal)
        {
            return _storeDataReader.GetProviderSpecificValue(ordinal);
        }

        /// <summary>
        /// implementation for DbDataReader.GetProviderSpecificValues() method
        /// </summary>
        /// <param name="values"></param>
        /// <returns></returns>
        [EditorBrowsableAttribute(EditorBrowsableState.Never)]
        public override int GetProviderSpecificValues(object[] values)
        {
            return _storeDataReader.GetProviderSpecificValues(values);
        }

        /// <summary>
        /// Get the DataTable that describes the columns of this data reader
        /// </summary>
        /// <returns>The DataTable describing the columns</returns>
        public override DataTable GetSchemaTable()
        {
            return this._storeDataReader.GetSchemaTable();
        }

        /// <summary>
        /// Get the string value of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the value</param>
        /// <returns>The string value</returns>
        public override string GetString(int ordinal)
        {
            return this._storeDataReader.GetString(ordinal);
        }

        /// <summary>
        /// Get the value of a column with the given ordinal
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the value</param>
        /// <returns>The value</returns>
        public override object GetValue(int ordinal)
        {
            return this._storeDataReader.GetValue(ordinal);
        }

        /// <summary>
        /// Get the values for all the columns and for the current row
        /// </summary>
        /// <param name="values">The array where values are copied into</param>
        /// <returns>The number of System.Object instances in the array</returns>
        public override int GetValues(object[] values)
        {
            return this._storeDataReader.GetValues(values);
        }

        /// <summary>
        /// Get whether the value of a column is DBNull
        /// </summary>
        /// <param name="ordinal">The ordinal of the column to retrieve the value</param>
        /// <returns>true if the column value is DBNull</returns>
        public override bool IsDBNull(int ordinal)
        {
            return this._storeDataReader.IsDBNull(ordinal);
        }

        /// <summary>
        /// Move the reader to the next result set when reading a batch of statements
        /// </summary>
        /// <returns>true if there are more result sets</returns>
        public override bool NextResult()
        {
            try 
            {
                return this._storeDataReader.NextResult();
            }
            catch (Exception e) 
            {
                if (EntityUtil.IsCatchableExceptionType(e)) 
                {
                    throw EntityUtil.CommandExecution(System.Data.Entity.Strings.EntityClient_StoreReaderFailed, e);
                }
                throw;
            }
        }

        /// <summary>
        /// Move the reader to the next row of the current result set
        /// </summary>
        /// <returns>true if there are more rows</returns>
        public override bool Read()
        {
            return this._storeDataReader.Read();
        }

        /// <summary>
        /// Get an enumerator for enumerating results over this data reader
        /// </summary>
        /// <returns>An enumerator for this data reader</returns>
        public override IEnumerator GetEnumerator()
        {
            return this._storeDataReader.GetEnumerator();
        }

        /// <summary>
        /// Used to return a nested DbDataRecord.
        /// </summary>
        public DbDataRecord GetDataRecord(int i)
        {
            if (null == this._storeExtendedDataRecord)
            {
                Debug.Assert(this.FieldCount == 0, "we have fields but no metadata?");
                // for a query with no results, any request is out of range...
                EntityUtil.ThrowArgumentOutOfRangeException("i");
            }
            return this._storeExtendedDataRecord.GetDataRecord(i);
        }

        /// <summary>
        /// Used to return a nested result
        /// </summary>
        public DbDataReader GetDataReader(int i)
        {
            return this.GetDbDataReader(i);
        }
    }
}