/Raven.Database/Bundles/Replication/Tasks/ReplicationStrategy.cs

using System;

using System.Linq;

using Raven.Abstractions.Data;

using Raven.Abstractions.Logging;

using Raven.Abstractions.Replication;

using Raven.Abstractions.Util;

using Raven.Database;

using Raven.Database.Data;

using Raven.Json.Linq;



namespace Raven.Bundles.Replication.Tasks

{

	public class ReplicationStrategy

	{

		private static readonly ILog log = LogManager.GetCurrentClassLogger();



		public bool FilterDocuments(string destinationId, string key, RavenJObject metadata)

		{

			if (IsSystemDocumentId(key))

			{

				log.Debug("Will not replicate document '{0}' to '{1}' because it is a system document", key, destinationId);

				return false;

			}

			if (metadata.ContainsKey(Constants.NotForReplication) && metadata.Value<bool>(Constants.NotForReplication))

				// not explicitly marked to skip

			{

				log.Debug("Will not replicate document '{0}' to '{1}' because it was marked as not for replication", key, destinationId); 

				return false;

			}

			if (metadata[Constants.RavenReplicationConflict] != null)

				// don't replicate conflicted documents, that just propagate the conflict

			{

				log.Debug("Will not replicate document '{0}' to '{1}' because it a conflict document", key, destinationId); 

				return false;

			}



			if (OriginsFromDestination(destinationId, metadata)) // prevent replicating back to source

			{

				log.Debug("Will not replicate document '{0}' to '{1}' because the destination server is the same server it originated from", key, destinationId); 

				return false;

			}



			switch (ReplicationOptionsBehavior)

			{

				case TransitiveReplicationOptions.None:

					var value = metadata.Value<string>(Constants.RavenReplicationSource);

			        if (value != null &&  (value != CurrentDatabaseId))

					{

						log.Debug("Will not replicate document '{0}' to '{1}' because it was not created on the current server, and TransitiveReplicationOptions = none", key, destinationId);

					    return false;

					}

			        break;

			}

			log.Debug("Will replicate '{0}' to '{1}'", key, destinationId);

			return true;



		}



		public bool OriginsFromDestination(string destinationId, RavenJObject metadata)

		{

			return metadata.Value<string>(Constants.RavenReplicationSource) == destinationId;

		}



		public bool IsSystemDocumentId(string key)

		{

			if (key.StartsWith("Raven/", StringComparison.OrdinalIgnoreCase)) // don't replicate system docs

			{

				if (key.StartsWith("Raven/Hilo/", StringComparison.OrdinalIgnoreCase) == false) // except for hilo documents

					return true;

			}

			return false;

		}



		public bool FilterAttachments(AttachmentInformation attachment, string destinationInstanceId)

		{

			if (attachment.Key.StartsWith("Raven/", StringComparison.OrdinalIgnoreCase) || // don't replicate system attachments

			    attachment.Key.StartsWith("transactions/recoveryInformation", StringComparison.OrdinalIgnoreCase)) // don't replicate transaction recovery information

				return false;



			// explicitly marked to skip

			if (attachment.Metadata.ContainsKey(Constants.NotForReplication) && attachment.Metadata.Value<bool>(Constants.NotForReplication))

				return false;



			if (attachment.Metadata.ContainsKey(Constants.RavenReplicationConflict))// don't replicate conflicted documents, that just propagate the conflict

				return false;



			// we don't replicate stuff that was created there

			if (attachment.Metadata.Value<string>(Constants.RavenReplicationSource) == destinationInstanceId)

				return false;



			switch (ReplicationOptionsBehavior)

			{

				case TransitiveReplicationOptions.None:

					return attachment.Metadata.Value<string>(Constants.RavenReplicationSource) == null ||

					       (attachment.Metadata.Value<string>(Constants.RavenReplicationSource) == CurrentDatabaseId);

			}

			return true;



		}



		public string CurrentDatabaseId { get; set; }



		public TransitiveReplicationOptions ReplicationOptionsBehavior { get; set; }

		public RavenConnectionStringOptions ConnectionStringOptions { get; set; }



		public override string ToString()

		{

			return string.Join(" ", new[]

			{

				ConnectionStringOptions.Url,

				ConnectionStringOptions.DefaultDatabase,

				ConnectionStringOptions.ApiKey

			}.Where(x => x != null));

		}



	}

}