Do not send backlog events

It is messy to resend then when clients restart, because none of them
deduplicates messages on msgi.

Some might if we wrapped the backlog in a 'chathistory' batch, but 1.
not all of them would, 2. it's hard to implement correctly.

Therefore, let's remove it entirely. If clients want the backlog, they
should implement support for the CHATHISTORY command.

Author: progval

lib/matrix_client/poller.ex

@@ -128,7 +128,7 @@ defmodule M51.MatrixClient.Poller do
     end)
   end
 
-  defp well_formed_event?(event, irc_state, write) do
+  defp well_formed_event?(is_backlog, event, irc_state, write) do
     case event do
       %{
         "content" => %{},
@@ -138,6 +138,9 @@ defmodule M51.MatrixClient.Poller do
       when is_binary(sender) and is_binary(type) ->
         true
 
+      _ when is_backlog ->
+        nil
+
       _ ->
         nick = M51.IrcConn.State.nick(irc_state)
 
@@ -162,7 +165,7 @@ defmodule M51.MatrixClient.Poller do
       room_event
       |> Map.get("state", %{})
       |> Map.get("events", [])
-      |> Enum.filter(fn event -> well_formed_event?(event, irc_state, write) end)
+      |> Enum.filter(fn event -> well_formed_event?(is_backlog, event, irc_state, write) end)
       # oldest first
       |> Enum.map(fn event ->
         event_id = Map.get(event, "event_id")
@@ -203,7 +206,7 @@ defmodule M51.MatrixClient.Poller do
     room_event
     |> Map.get("timeline", %{})
     |> Map.get("events", [])
-    |> Enum.filter(fn event -> well_formed_event?(event, irc_state, write) end)
+    |> Enum.filter(fn event -> well_formed_event?(is_backlog, event, irc_state, write) end)
     # oldest first
     |> Enum.map(fn event ->
       event_id = Map.get(event, "event_id")
@@ -279,11 +282,21 @@ defmodule M51.MatrixClient.Poller do
     end
   end
 
+  def handle_event(
+        _sup_pid,
+        _room_id,
+        _sender,
+        true,
+        _write,
+        %{"type" => "m.room.join_rules"}
+      ) do
+  end
+
   def handle_event(
         sup_pid,
         room_id,
         sender,
-        is_backlog,
+        false,
         write,
         %{
           "type" => "m.room.join_rules",
@@ -295,24 +308,22 @@ defmodule M51.MatrixClient.Poller do
     channel = M51.MatrixClient.State.room_irc_channel(state, room_id)
     send = make_send_function(sup_pid, event, write)
 
-    if !is_backlog do
-      mode =
-        case join_rule do
-          "public" -> "-i"
-          "knock" -> "+i"
-          "invite" -> "+i"
-          "private" -> "+i"
-          _ -> nil
-        end
-
-      if mode != nil do
-        send.(%M51.Irc.Command{
-          tags: %{"account" => sender},
-          source: nick2nuh(sender),
-          command: "MODE",
-          params: [channel, mode]
-        })
+    mode =
+      case join_rule do
+        "public" -> "-i"
+        "knock" -> "+i"
+        "invite" -> "+i"
+        "private" -> "+i"
+        _ -> nil
       end
+
+    if mode != nil do
+      send.(%M51.Irc.Command{
+        tags: %{"account" => sender},
+        source: nick2nuh(sender),
+        command: "MODE",
+        params: [channel, mode]
+      })
     end
 
     nil
@@ -435,11 +446,23 @@ defmodule M51.MatrixClient.Poller do
     nil
   end
 
+  def handle_event(
+        _sup_pid,
+        _room_id,
+        _sender,
+        true,
+        _write,
+        %{"type" => "m.room.message"}
+      ) do
+    # do not show messages from the backlog
+    nil
+  end
+
   def handle_event(
         sup_pid,
         room_id,
         sender,
-        _is_backlog,
+        false,
         write,
         %{"type" => "m.room.message", "content" => %{}} = event
       ) do
@@ -669,11 +692,22 @@ defmodule M51.MatrixClient.Poller do
     nil
   end
 
+  def handle_event(
+        _sup_pid,
+        _room_id,
+        _sender,
+        true,
+        _write,
+        %{"type" => "m.reaction"}
+      ) do
+    nil
+  end
+
   def handle_event(
         sup_pid,
         room_id,
         sender,
-        _is_backlog,
+        false,
         write,
         %{"type" => "m.reaction", "content" => %{}} = event
       ) do
@@ -726,11 +760,22 @@ defmodule M51.MatrixClient.Poller do
     end
   end
 
+  def handle_event(
+        _sup_pid,
+        _room_id,
+        _sender,
+        true,
+        _write,
+        %{"type" => "m.sticker"}
+      ) do
+    nil
+  end
+
   def handle_event(
         sup_pid,
         room_id,
         sender,
-        _is_backlog,
+        false,
         write,
         %{"type" => "m.sticker", "content" => %{}} = event
       ) do
@@ -781,11 +826,22 @@ defmodule M51.MatrixClient.Poller do
     end
   end
 
+  def handle_event(
+        _sup_pid,
+        _room_id,
+        _sender,
+        true,
+        _write,
+        %{"type" => "m.room.redaction", "content" => %{}}
+      ) do
+    nil
+  end
+
   def handle_event(
         sup_pid,
         room_id,
         sender,
-        _is_backlog,
+        false,
         write,
         %{"type" => "m.room.redaction", "content" => %{}} = event
       ) do
@@ -828,11 +884,22 @@ defmodule M51.MatrixClient.Poller do
     })
   end
 
+  def handle_event(
+        _sup_pid,
+        _room_id,
+        _sender,
+        true,
+        _write,
+        %{"type" => "m.room.encrypted"}
+      ) do
+    nil
+  end
+
   def handle_event(
         sup_pid,
         room_id,
         sender,
-        _is_backlog,
+        false,
         write,
         %{"type" => "m.room.encrypted", "content" => %{}} = event
       ) do
@@ -954,7 +1021,11 @@ defmodule M51.MatrixClient.Poller do
     # ignore these
   end
 
-  def handle_event(sup_pid, room_id, _sender, _is_backlog, write, event) do
+  def handle_event(_sup_pid, _room_id, _sender, true, _write, _event) do
+    # Unknown or malformed event in the backlog
+  end
+
+  def handle_event(sup_pid, room_id, _sender, false, write, event) do
     state = M51.IrcConn.Supervisor.matrix_state(sup_pid)
     channel = M51.MatrixClient.State.room_irc_channel(state, room_id)
     send = make_send_function(sup_pid, event, write)
@@ -988,7 +1059,7 @@ defmodule M51.MatrixClient.Poller do
     # TODO
   end
 
-  defp handle_invited_room(sup_pid, _is_backlog, handled_event_ids, room_id, write, room_event) do
+  defp handle_invited_room(sup_pid, is_backlog, handled_event_ids, room_id, write, room_event) do
     irc_state = M51.IrcConn.Supervisor.state(sup_pid)
     state = M51.IrcConn.Supervisor.matrix_state(sup_pid)
     nick = M51.IrcConn.State.nick(irc_state)
@@ -997,7 +1068,7 @@ defmodule M51.MatrixClient.Poller do
     room_event
     |> Map.get("invite_state", %{})
     |> Map.get("events", [])
-    |> Enum.filter(fn event -> well_formed_event?(event, irc_state, write) end)
+    |> Enum.filter(fn event -> well_formed_event?(is_backlog, event, irc_state, write) end)
     # oldest first
     |> Enum.map(fn event ->
       event_id = Map.get(event, "event_id")