[smuxi] Engine: implemented SqliteMessageBuffer.RemoveAt()

[Mirco M. M. Bauer <mmmbauer src gnome org>]

commit a12bab068228cf01c39311e95373b8d5d6541f65
Author: Mirco Bauer <meebey meebey net>
Date:   Wed Feb 26 22:45:47 2014 +0100

    Engine: implemented SqliteMessageBuffer.RemoveAt()

 src/Engine/MessageBuffers/SqliteMessageBuffer.cs |   27 ++++++++++++++++++++-
 1 files changed, 25 insertions(+), 2 deletions(-)
---
diff --git a/src/Engine/MessageBuffers/SqliteMessageBuffer.cs 
b/src/Engine/MessageBuffers/SqliteMessageBuffer.cs
index c377f04..44210ad 100644
--- a/src/Engine/MessageBuffers/SqliteMessageBuffer.cs
+++ b/src/Engine/MessageBuffers/SqliteMessageBuffer.cs
@@ -163,9 +163,32 @@ namespace Smuxi.Engine
             throw new NotImplementedException ();
         }
 
-        public override void RemoveAt(int index)
+        public override void RemoveAt(int offset)
         {
-            throw new NotImplementedException ();
+            int id = -1;
+            using (var cmd = Connection.CreateCommand()) {
+                cmd.CommandText = "SELECT ID FROM Messages " +
+                                  " ORDER BY ID " +
+                                  " LIMIT 1 OFFSET @offset";
+
+                var param = cmd.CreateParameter();
+                param.ParameterName = "offset";
+                param.Value = offset;
+                cmd.Parameters.Add(param);
+
+                id = (int) Convert.ChangeType(cmd.ExecuteScalar(), typeof(int));
+            }
+
+            using (var cmd = Connection.CreateCommand()) {
+                cmd.CommandText = "DELETE FROM Messages WHERE ID = @id";
+
+                var param = cmd.CreateParameter();
+                param.ParameterName = "id";
+                param.Value = id;
+                cmd.Parameters.Add(param);
+
+                cmd.ExecuteNonQuery();
+            }
         }
 
         public override void Flush()