feat(chat): implement pull-to-refresh functionality and pagination for chat history

src/stores/chat/machine/history-flow.ts

@@ -1,11 +1,14 @@
 import {
+  applyOlderHistoryLoadedOutput,
   applyHistoryLoadedOutput,
   applyNetworkHistoryLoadedOutput,
+  canLoadMoreHistory,
 } from "../helper/history";
 import {
   countLockedHistoryMessages,
   shouldPromptUnlockHistory,
 } from "../helper/unlock";
+import type { ChatState } from "../chat-state";
 import { baseChatMachineSetup } from "./setup";
 
 const applyLocalHistoryLoadedAction = baseChatMachineSetup.assign(
@@ -49,6 +52,30 @@ const markHistoryLoadFailedAction = baseChatMachineSetup.assign({
   historyLoaded: true,
 });
 
+const markLoadMoreHistoryStartedAction = baseChatMachineSetup.assign({
+  isLoadingMoreHistory: true,
+});
+
+const requestOlderHistoryPageAction = baseChatMachineSetup.sendTo(
+  "loadMoreHistory",
+  ({ context }) => ({
+    type: "LoadMoreHistoryPageRequested",
+    offset: context.nextHistoryOffset,
+    limit: context.historyLimit,
+  }),
+);
+
+const applyOlderHistoryLoadedAction = baseChatMachineSetup.assign(
+  ({ context, event }) => {
+    if (event.type !== "ChatOlderHistoryLoaded") return {};
+    return applyOlderHistoryLoadedOutput(context, event.output);
+  },
+);
+
+const markOlderHistoryLoadFailedAction = baseChatMachineSetup.assign({
+  isLoadingMoreHistory: false,
+});
+
 export const historyMachineSetup = baseChatMachineSetup.extend({
   actions: {
     applyLocalHistoryLoaded: applyLocalHistoryLoadedAction,
@@ -58,9 +85,27 @@ export const historyMachineSetup = baseChatMachineSetup.extend({
     showUnlockHistoryPromptFromNetwork:
       showUnlockHistoryPromptFromNetworkAction,
     markHistoryLoadFailed: markHistoryLoadFailedAction,
+    markLoadMoreHistoryStarted: markLoadMoreHistoryStartedAction,
+    requestOlderHistoryPage: requestOlderHistoryPageAction,
+    applyOlderHistoryLoaded: applyOlderHistoryLoadedAction,
+    markOlderHistoryLoadFailed: markOlderHistoryLoadFailedAction,
   },
 });
 
+export const historyPaginationTransitions = {
+  ChatLoadMoreHistoryRequested: {
+    guard: ({ context }: { context: ChatState }) =>
+      canLoadMoreHistory(context),
+    actions: ["markLoadMoreHistoryStarted", "requestOlderHistoryPage"],
+  },
+  ChatOlderHistoryLoaded: {
+    actions: "applyOlderHistoryLoaded",
+  },
+  ChatOlderHistoryLoadFailed: {
+    actions: "markOlderHistoryLoadFailed",
+  },
+} as const;
+
 export const guestInitializingState = historyMachineSetup.createStateConfig({
   on: {
     ChatLocalHistoryLoaded: {