#region Apache License
//
// Licensed to the Apache Software Foundation (ASF) under one or more 
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership. 
// The ASF licenses this file to you 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

using System.Data;
using System.Data.SqlClient;
using log4net.Appender;
using log4net.Core;

namespace SampleAppendersApp.Appender
{
	/// <summary>
	/// Simple database appender
	/// </summary>
	/// <remarks>
	/// <para>
	/// This database appender is very simple and does not support a configurable
	/// data schema. The schema supported is hardcoded into the appender.
	/// Also by not extending the AppenderSkeleton base class this appender
	/// avoids the serializable locking that it enforces.
	/// </para>
	/// <para>
	/// This appender can be subclassed to change the database connection
	/// type, or the database schema supported.
	/// </para>
	/// <para>
	/// To change the database connection type the <see cref="GetConnection"/>
	/// method must be overridden.
	/// </para>
	/// <para>
	/// To change the database schema supported by the appender the <see cref="InitializeCommand"/>
	/// and <see cref="SetCommandValues"/> methods must be overridden.
	/// </para>
	/// </remarks>
	public class FastDbAppender : IAppender, IBulkAppender, IOptionHandler
	{
		private string m_name;
		private string m_connectionString;

		public string Name
		{
			get { return m_name; }
			set { m_name = value; }
		}

		public string ConnectionString
		{
			get { return m_connectionString; }
			set { m_connectionString = value; }
		}

		public virtual void ActivateOptions() 
		{
		}

		public virtual void Close()
		{
		}

		public virtual void DoAppend(LoggingEvent loggingEvent)
		{
			using(IDbConnection connection = GetConnection())
			{
				if (connection.State == ConnectionState.Closed)
				{
					// Open the connection for each event, this takes advantage
					// of the builtin connection pooling
					connection.Open();
				}

				using(IDbCommand command = connection.CreateCommand())
				{
					InitializeCommand(command);

					SetCommandValues(command, loggingEvent);
					command.ExecuteNonQuery();
				}
			}
		}

		public virtual void DoAppend(LoggingEvent[] loggingEvents)
		{
			using(IDbConnection connection = GetConnection())
			{
				// Open the connection for each event, this takes advantage
				// of the builtin connection pooling
				connection.Open();

				using(IDbCommand command = connection.CreateCommand())
				{
					InitializeCommand(command);

					foreach(LoggingEvent loggingEvent in loggingEvents)
					{
						SetCommandValues(command, loggingEvent);
						command.ExecuteNonQuery();
					}
				}
			}
		}

		/// <summary>
		/// Create the connection object
		/// </summary>
		/// <returns>the connection</returns>
		/// <remarks>
		/// <para>
		/// This implementation returns a <see cref="SqlConnection"/>.
		/// To change the connection subclass this appender and
		/// return a different connection type.
		/// </para>
		/// </remarks>
		virtual protected IDbConnection GetConnection()
		{
			return new SqlConnection(m_connectionString);
		}

		/// <summary>
		/// Initialize the command object supplied
		/// </summary>
		/// <param name="command">the command to initialize</param>
		/// <remarks>
		/// <para>
		/// This method must setup the database command and the
		/// parameters.
		/// </para>
		/// </remarks>
		virtual protected void InitializeCommand(IDbCommand command)
		{
			command.CommandType = CommandType.Text;
			command.CommandText = "INSERT INTO [LogTable] ([Time],[Logger],[Level],[Thread],[Message]) VALUES (@Time,@Logger,@Level,@Thread,@Message)";

			IDbDataParameter param;
			
			// @Time
			param = command.CreateParameter();
			param.ParameterName = "@Time";
			param.DbType = DbType.DateTime;
			command.Parameters.Add(param);
			
			// @Logger
			param = command.CreateParameter();
			param.ParameterName = "@Logger";
			param.DbType = DbType.String;
			command.Parameters.Add(param);
			
			// @Level
			param = command.CreateParameter();
			param.ParameterName = "@Level";
			param.DbType = DbType.String;
			command.Parameters.Add(param);
			
			// @Thread
			param = command.CreateParameter();
			param.ParameterName = "@Thread";
			param.DbType = DbType.String;
			command.Parameters.Add(param);
			
			// @Message
			param = command.CreateParameter();
			param.ParameterName = "@Message";
			param.DbType = DbType.String;
			command.Parameters.Add(param);
		}

		/// <summary>
		/// Set the values for the command parameters
		/// </summary>
		/// <param name="command">the command to update</param>
		/// <param name="loggingEvent">the current logging event to retrieve the values from</param>
		/// <remarks>
		/// <para>
		/// Set the values of the parameters created by the
		/// <see cref="InitializeCommand"/> method.
		/// </para>
		/// </remarks>
		virtual protected void SetCommandValues(IDbCommand command, LoggingEvent loggingEvent)
		{
			((IDbDataParameter)command.Parameters["@Time"]).Value = loggingEvent.TimeStamp;
			((IDbDataParameter)command.Parameters["@Logger"]).Value = loggingEvent.LoggerName;
			((IDbDataParameter)command.Parameters["@Level"]).Value = loggingEvent.Level.Name;
			((IDbDataParameter)command.Parameters["@Thread"]).Value = loggingEvent.ThreadName;
			((IDbDataParameter)command.Parameters["@Message"]).Value = loggingEvent.RenderedMessage;
		}
	}
}