- Implement message history export to text file

ChatTwo/MessageStore.cs

@@ -387,7 +387,7 @@ internal class MessageStore : IDisposable
         cmd.ExecuteNonQuery();
     }
 
-    internal long CountDateRange(DateTime after, DateTime before, uint[] channels, ulong? receiver = null)
+    internal long CountDateRange(DateTime after, DateTime before, IEnumerable<uint> channels, ulong? receiver = null)
     {
         List<string> whereClauses = ["deleted = false"];
         if (receiver != null)
@@ -416,7 +416,47 @@ internal class MessageStore : IDisposable
         return (long) cmd.ExecuteScalar()!;
     }
 
-    internal MessageEnumerator GetDateRange(DateTime after, DateTime before, uint[] channels, ulong? receiver = null, int page = 0)
+    internal MessageEnumerator GetDateRange(DateTime after, DateTime before, IEnumerable<uint> channels, ulong? receiver = null)
+    {
+        List<string> whereClauses = ["deleted = false"];
+        if (receiver != null)
+            whereClauses.Add("Receiver = $Receiver");
+
+        whereClauses.Add("Date BETWEEN $After AND $Before");
+        whereClauses.Add($"Channel IN ({string.Join(", ", channels)})");
+
+        var whereClause = $"WHERE {string.Join(" AND ", whereClauses)}";
+
+        var cmd = Connection.CreateCommand();
+        // Select last N messages by date DESC, but reverse the order to get
+        // them in ascending order.
+        cmd.CommandText = @"
+            SELECT
+                Id,
+                Receiver,
+                ContentId,
+                Date,
+                Code,
+                Sender,
+                Content,
+                SenderSource,
+                ContentSource,
+                SortCode,
+                ExtraChatChannel
+            FROM messages
+            " + whereClause;
+        cmd.CommandTimeout = 120; // this could take a while on slow computers
+
+        if (receiver != null)
+            cmd.Parameters.AddWithValue("$Receiver", receiver);
+
+        cmd.Parameters.AddWithValue("$After", ((DateTimeOffset) after).ToUnixTimeMilliseconds());
+        cmd.Parameters.AddWithValue("$Before", ((DateTimeOffset) before).ToUnixTimeMilliseconds());
+
+        return new MessageEnumerator(cmd.ExecuteReader());
+    }
+
+    internal MessageEnumerator GetPagedDateRange(DateTime after, DateTime before, IEnumerable<uint> channels, ulong? receiver = null, int page = 0)
     {
         List<string> whereClauses = ["deleted = false"];
         if (receiver != null)