test: stabilize channel mode and discussion coverage

plugin/core/channel-modes.js

@@ -0,0 +1,43 @@
+const channelStates = new Map();
+
+export function getChannelState(channelId) {
+  if (!channelStates.has(channelId)) {
+    channelStates.set(channelId, {
+      mode: "normal",
+      shuffling: false,
+    });
+  }
+  return channelStates.get(channelId);
+}
+
+export function enterMultiMessageMode(channelId) {
+  const state = getChannelState(channelId);
+  state.mode = "multi-message";
+  channelStates.set(channelId, state);
+}
+
+export function exitMultiMessageMode(channelId) {
+  const state = getChannelState(channelId);
+  state.mode = "normal";
+  channelStates.set(channelId, state);
+}
+
+export function isMultiMessageMode(channelId) {
+  return getChannelState(channelId).mode === "multi-message";
+}
+
+export function setChannelShuffling(channelId, enabled) {
+  const state = getChannelState(channelId);
+  state.shuffling = enabled;
+  channelStates.set(channelId, state);
+}
+
+export function getChannelShuffling(channelId) {
+  return getChannelState(channelId).shuffling;
+}
+
+export function markLastShuffled(channelId) {
+  const state = getChannelState(channelId);
+  state.lastShuffledAt = Date.now();
+  channelStates.set(channelId, state);
+}