#region Copyright & License
//
// Copyright 2001-2005 The Apache Software Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#endregion

// SSCLI 1.0 has no support for ADO.NET
#if !SSCLI

using System;
using System.Collections;
using System.Data;
using System.IO;
using System.Reflection;

using log4net.Util;
using log4net.Layout;
using log4net.Core;

namespace log4net.Appender
{
	/// <summary>
	/// Appender that logs to a database.
	/// </summary>
	/// <remarks>
	/// <para>
	/// <see cref="AdoNetAppender"/> appends logging events to a table within a
	/// database. The appender can be configured to specify the connection 
	/// string by setting the <see cref="ConnectionString"/> property. 
	/// The connection type (provider) can be specified by setting the <see cref="ConnectionType"/>
	/// property. For more information on database connection strings for
	/// your specific database see <a href="http://www.connectionstrings.com/">http://www.connectionstrings.com/</a>.
	/// </para>
	/// <para>
	/// Records are written into the database either using a prepared
	/// statement or a stored procedure. The <see cref="CommandType"/> property
	/// is set to <see cref="System.Data.CommandType.Text"/> (<c>System.Data.CommandType.Text</c>) to specify a prepared statement
	/// or to <see cref="System.Data.CommandType.StoredProcedure"/> (<c>System.Data.CommandType.StoredProcedure</c>) to specify a stored
	/// procedure.
	/// </para>
	/// <para>
	/// The prepared statement text or the name of the stored procedure
	/// must be set in the <see cref="CommandText"/> property.
	/// </para>
	/// <para>
	/// The prepared statement or stored procedure can take a number
	/// of parameters. Parameters are added using the <see cref="AddParameter"/>
	/// method. This adds a single <see cref="AdoNetAppenderParameter"/> to the
	/// ordered list of parameters. The <see cref="AdoNetAppenderParameter"/>
	/// type may be subclassed if required to provide database specific
	/// functionality. The <see cref="AdoNetAppenderParameter"/> specifies
	/// the parameter name, database type, size, and how the value should
	/// be generated using a <see cref="ILayout"/>.
	/// </para>
	/// </remarks>
	/// <example>
	/// An example of a SQL Server table that could be logged to:
	/// <code lang="SQL">
	/// CREATE TABLE [dbo].[Log] ( 
	///   [ID] [int] IDENTITY (1, 1) NOT NULL ,
	///   [Date] [datetime] NOT NULL ,
	///   [Thread] [varchar] (255) NOT NULL ,
	///   [Level] [varchar] (20) NOT NULL ,
	///   [Logger] [varchar] (255) NOT NULL ,
	///   [Message] [varchar] (4000) NOT NULL 
	/// ) ON [PRIMARY]
	/// </code>
	/// </example>
	/// <example>
	/// An example configuration to log to the above table:
	/// <code lang="XML" escaped="true">
	/// <appender name="AdoNetAppender_SqlServer" type="log4net.Appender.AdoNetAppender" >
	///   <connectionType value="System.Data.SqlClient.SqlConnection, System.Data, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
	///   <connectionString value="data source=SQLSVR;initial catalog=test_log4net;integrated security=false;persist security info=True;User ID=sa;Password=sa" />
	///   <commandText value="INSERT INTO Log ([Date],[Thread],[Level],[Logger],[Message]) VALUES (@log_date, @thread, @log_level, @logger, @message)" />
	///   <parameter>
	///     <parameterName value="@log_date" />
	///     <dbType value="DateTime" />
	///     <layout type="log4net.Layout.PatternLayout" value="%date{yyyy'-'MM'-'dd HH':'mm':'ss'.'fff}" />
	///   </parameter>
	///   <parameter>
	///     <parameterName value="@thread" />
	///     <dbType value="String" />
	///     <size value="255" />
	///     <layout type="log4net.Layout.PatternLayout" value="%thread" />
	///   </parameter>
	///   <parameter>
	///     <parameterName value="@log_level" />
	///     <dbType value="String" />
	///     <size value="50" />
	///     <layout type="log4net.Layout.PatternLayout" value="%level" />
	///   </parameter>
	///   <parameter>
	///     <parameterName value="@logger" />
	///     <dbType value="String" />
	///     <size value="255" />
	///     <layout type="log4net.Layout.PatternLayout" value="%logger" />
	///   </parameter>
	///   <parameter>
	///     <parameterName value="@message" />
	///     <dbType value="String" />
	///     <size value="4000" />
	///     <layout type="log4net.Layout.PatternLayout" value="%message" />
	///   </parameter>
	/// </appender>
	/// </code>
	/// </example>
	/// <author>Julian Biddle</author>
	/// <author>Nicko Cadell</author>
	/// <author>Gert Driesen</author>
	/// <author>Lance Nehring</author>
	public class AdoNetAppender : BufferingAppenderSkeleton
	{
		#region Public Instance Constructors

		/// <summary> 
		/// Initializes a new instance of the <see cref="AdoNetAppender" /> class.
		/// </summary>
		/// <remarks>
		/// Public default constructor to initialize a new instance of this class.
		/// </remarks>
		public AdoNetAppender()
		{
			m_connectionType = "System.Data.OleDb.OleDbConnection, System.Data, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089";
			m_useTransactions = true;
			m_commandType = System.Data.CommandType.Text;
			m_parameters = new ArrayList();
			m_reconnectOnError = false;
		}

		#endregion // Public Instance Constructors

		#region Public Instance Properties

		/// <summary>
		/// Gets or sets the database connection string that is used to connect to 
		/// the database.
		/// </summary>
		/// <value>
		/// The database connection string used to connect to the database.
		/// </value>
		/// <remarks>
		/// <para>
		/// The connections string is specific to the connection type.
		/// See <see cref="ConnectionType"/> for more information.
		/// </para>
		/// </remarks>
		/// <example>Connection string for MS Access via ODBC:
		/// <code>"DSN=MS Access Database;UID=admin;PWD=;SystemDB=C:\data\System.mdw;SafeTransactions = 0;FIL=MS Access;DriverID = 25;DBQ=C:\data\train33.mdb"</code>
		/// </example>
		/// <example>Another connection string for MS Access via ODBC:
		/// <code>"Driver={Microsoft Access Driver (*.mdb)};DBQ=C:\Work\cvs_root\log4net-1.2\access.mdb;UID=;PWD=;"</code>
		/// </example>
		/// <example>Connection string for MS Access via OLE DB:
		/// <code>"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Work\cvs_root\log4net-1.2\access.mdb;User Id=;Password=;"</code>
		/// </example>
		public string ConnectionString
		{
			get { return m_connectionString; }
			set { m_connectionString = value; }
		}

		/// <summary>
		/// Gets or sets the type name of the <see cref="IDbConnection"/> connection
		/// that should be created.
		/// </summary>
		/// <value>
		/// The type name of the <see cref="IDbConnection"/> connection.
		/// </value>
		/// <remarks>
		/// <para>
		/// The type name of the ADO.NET provider to use.
		/// </para>
		/// <para>
		/// The default is to use the OLE DB provider.
		/// </para>
		/// </remarks>
		/// <example>Use the OLE DB Provider. This is the default value.
		/// <code>System.Data.OleDb.OleDbConnection, System.Data, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</code>
		/// </example>
		/// <example>Use the MS SQL Server Provider. 
		/// <code>System.Data.SqlClient.SqlConnection, System.Data, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</code>
		/// </example>
		/// <example>Use the ODBC Provider. 
		/// <code>Microsoft.Data.Odbc.OdbcConnection,Microsoft.Data.Odbc,version=1.0.3300.0,publicKeyToken=b77a5c561934e089,culture=neutral</code>
		/// This is an optional package that you can download from 
		/// <a href="http://msdn.microsoft.com/downloads">http://msdn.microsoft.com/downloads</a> 
		/// search for <b>ODBC .NET Data Provider</b>.
		/// </example>
		/// <example>Use the Oracle Provider. 
		/// <code>System.Data.OracleClient.OracleConnection, System.Data.OracleClient, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</code>
		/// This is an optional package that you can download from 
		/// <a href="http://msdn.microsoft.com/downloads">http://msdn.microsoft.com/downloads</a> 
		/// search for <b>.NET Managed Provider for Oracle</b>.
		/// </example>
		public string ConnectionType
		{
			get { return m_connectionType; }
			set { m_connectionType = value; }
		}

		/// <summary>
		/// Gets or sets the command text that is used to insert logging events
		/// into the database.
		/// </summary>
		/// <value>
		/// The command text used to insert logging events into the database.
		/// </value>
		/// <remarks>
		/// <para>
		/// Either the text of the prepared statement or the
		/// name of the stored procedure to execute to write into
		/// the database.
		/// </para>
		/// <para>
		/// The <see cref="CommandType"/> property determines if
		/// this text is a prepared statement or a stored procedure.
		/// </para>
		/// </remarks>
		public string CommandText
		{
			get { return m_commandText; }
			set { m_commandText = value; }
		}

		/// <summary>
		/// Gets or sets the command type to execute.
		/// </summary>
		/// <value>
		/// The command type to execute.
		/// </value>
		/// <remarks>
		/// <para>
		/// This value may be either <see cref="System.Data.CommandType.Text"/> (<c>System.Data.CommandType.Text</c>) to specify
		/// that the <see cref="CommandText"/> is a prepared statement to execute, 
		/// or <see cref="System.Data.CommandType.StoredProcedure"/> (<c>System.Data.CommandType.StoredProcedure</c>) to specify that the
		/// <see cref="CommandText"/> property is the name of a stored procedure
		/// to execute.
		/// </para>
		/// <para>
		/// The default value is <see cref="System.Data.CommandType.Text"/> (<c>System.Data.CommandType.Text</c>).
		/// </para>
		/// </remarks>
		public CommandType CommandType
		{
			get { return m_commandType; }
			set { m_commandType = value; }
		}

		/// <summary>
		/// Should transactions be used to insert logging events in the database.
		/// </summary>
		/// <value>
		/// <c>true</c> if transactions should be used to insert logging events in
		/// the database, otherwise <c>false</c>. The default value is <c>true</c>.
		/// </value>
		/// <remarks>
		/// <para>
		/// Gets or sets a value that indicates whether transactions should be used
		/// to insert logging events in the database.
		/// </para>
		/// <para>
		/// When set a single transaction will be used to insert the buffered events
		/// into the database. Otherwise each event will be inserted without using
		/// an explicit transaction.
		/// </para>
		/// </remarks>
		public bool UseTransactions
		{
			get { return m_useTransactions; }
			set { m_useTransactions = value; }
		}

		/// <summary>
		/// Gets or sets the <see cref="SecurityContext"/> used to call the NetSend method.
		/// </summary>
		/// <value>
		/// The <see cref="SecurityContext"/> used to call the NetSend method.
		/// </value>
		/// <remarks>
		/// <para>
		/// Unless a <see cref="SecurityContext"/> specified here for this appender
		/// the <see cref="SecurityContextProvider.DefaultProvider"/> is queried for the
		/// security context to use. The default behavior is to use the security context
		/// of the current thread.
		/// </para>
		/// </remarks>
		public SecurityContext SecurityContext 
		{
			get { return m_securityContext; }
			set { m_securityContext = value; }
		}

		/// <summary>
		/// Should this appender try to reconnect to the database on error.
		/// </summary>
		/// <value>
		/// <c>true</c> if the appender should try to reconnect to the database after an
		/// error has occurred, otherwise <c>false</c>. The default value is <c>false</c>, 
		/// i.e. not to try to reconnect.
		/// </value>
		/// <remarks>
		/// <para>
		/// The default behaviour is for the appender not to try to reconnect to the
		/// database if an error occurs. Subsequent logging events are discarded.
		/// </para>
		/// <para>
		/// To force the appender to attempt to reconnect to the database set this
		/// property to <c>true</c>.
		/// </para>
		/// <note>
		/// When the appender attempts to connect to the database there may be a
		/// delay of up to the connection timeout specified in the connection string.
		/// This delay will block the calling application's thread. 
		/// Until the connection can be reestablished this potential delay may occur multiple times.
		/// </note>
		/// </remarks>
		public bool ReconnectOnError
		{
			get { return m_reconnectOnError; }
			set { m_reconnectOnError = value; }
		}

		#endregion // Public Instance Properties

		#region Protected Instance Properties

		/// <summary>
		/// Gets or sets the underlying <see cref="IDbConnection" />.
		/// </summary>
		/// <value>
		/// The underlying <see cref="IDbConnection" />.
		/// </value>
		/// <remarks>
		/// <see cref="AdoNetAppender" /> creates a <see cref="IDbConnection" /> to insert 
		/// logging events into a database.  Classes deriving from <see cref="AdoNetAppender" /> 
		/// can use this property to get or set this <see cref="IDbConnection" />.  Use the 
		/// underlying <see cref="IDbConnection" /> returned from <see cref="Connection" /> if 
		/// you require access beyond that which <see cref="AdoNetAppender" /> provides.
		/// </remarks>
		protected IDbConnection Connection 
		{
			get { return this.m_dbConnection; }
			set { this.m_dbConnection = value; }
		}

		#endregion // Protected Instance Properties

		#region Implementation of IOptionHandler

		/// <summary>
		/// Initialize the appender based on the options set
		/// </summary>
		/// <remarks>
		/// <para>
		/// This is part of the <see cref="IOptionHandler"/> delayed object
		/// activation scheme. The <see cref="ActivateOptions"/> method must 
		/// be called on this object after the configuration properties have
		/// been set. Until <see cref="ActivateOptions"/> is called this
		/// object is in an undefined state and must not be used. 
		/// </para>
		/// <para>
		/// If any of the configuration properties are modified then 
		/// <see cref="ActivateOptions"/> must be called again.
		/// </para>
		/// </remarks>
		override public void ActivateOptions() 
		{
			base.ActivateOptions();

			// Are we using a command object
			m_usePreparedCommand = (m_commandText != null && m_commandText.Length > 0);

			if (m_securityContext == null)
			{
				m_securityContext = SecurityContextProvider.DefaultProvider.CreateSecurityContext(this);
			}

			InitializeDatabaseConnection();