Files
gitmost/apps/client/src/features/ai-chat/components/chat-thread.tsx
2026-06-26 05:22:20 +03:00

494 lines
22 KiB
TypeScript

import { useCallback, useEffect, useMemo, useRef, useState } from "react";
import { generateId } from "ai";
import { ActionIcon, Box, Group, Stack, Text } from "@mantine/core";
import { IconClockHour4, IconX } from "@tabler/icons-react";
import { useTranslation } from "react-i18next";
import { useChat, type UIMessage } from "@ai-sdk/react";
import { DefaultChatTransport } from "ai";
import MessageList from "@/features/ai-chat/components/message-list.tsx";
import ChatInput from "@/features/ai-chat/components/chat-input.tsx";
import RoleCards from "@/features/ai-chat/components/role-cards.tsx";
import ChatErrorAlert from "@/features/ai-chat/components/chat-error-alert.tsx";
import ChatStoppedNotice from "@/features/ai-chat/components/chat-stopped-notice.tsx";
import {
IAiChatMessageRow,
IAiRole,
} from "@/features/ai-chat/types/ai-chat.types.ts";
import {
roleLaunchMessage,
shouldResetRolePicked,
} from "@/features/ai-chat/utils/role-launch.ts";
import { describeChatError } from "@/features/ai-chat/utils/error-message.ts";
import { extractServerChatId } from "@/features/ai-chat/utils/adopt-chat-id.ts";
import { liveTurnTokens } from "@/features/ai-chat/utils/count-stream-tokens.ts";
import {
dequeue,
enqueueMessage,
removeQueuedById,
type QueuedMessage,
} from "@/features/ai-chat/utils/queue-helpers.ts";
import classes from "@/features/ai-chat/components/ai-chat.module.css";
/** The page the user is currently viewing, sent as chat context. */
export interface OpenPageContext {
id: string;
title: string;
}
interface ChatThreadProps {
/** The open chat id, or null for a brand-new (not-yet-created) chat. */
chatId: string | null;
/** This thread's mount key (the same value the parent uses as React `key`).
* Forwarded to onTurnFinished so the session can tell a turn finishing on the
* CURRENT thread from one ABANDONED by New chat mid-stream — whose onFinish/
* onError still fire after unmount and must not adopt the abandoned chat (#161). */
threadKey?: string;
/** Persisted rows to seed initial messages (existing chats only). */
initialRows?: IAiChatMessageRow[];
/** The page currently open in the workspace, or null on a non-page route.
* Sent with each turn so the agent knows what "this page" refers to. */
openPage?: OpenPageContext | null;
/** The agent role selected for a NEW chat (null = universal assistant). Sent
* in the request body so the server persists it on chat creation; ignored by
* the server for existing chats (the role is read from the chat row). */
roleId?: string | null;
/** Enabled roles for the new-chat empty state (only meaningful when
* `chatId === null`). Rendered as the colored role cards. */
roles?: IAiRole[];
/** Notify the parent which role was picked via a card, so it can update the
* header badge / assistant name for the brand-new chat. */
onRolePicked?: (role: IAiRole) => void;
/** Display name for the assistant label / typing line (the role name);
* forwarded to MessageList. Absent => the generic "AI agent". */
assistantName?: string;
/** Called when a turn finishes; the parent refreshes the chat list and, for a
* new chat, adopts the freshly created chat id. `serverChatId` is the
* authoritative id the server streamed on the assistant message metadata, or
* undefined on a failed turn — see adopt-chat-id.ts for the full #137 design.
* `finishingThreadKey` (this thread's mount key) lets the session ignore a turn
* finishing on a thread already abandoned by New chat mid-stream (#161). */
onTurnFinished: (serverChatId?: string, finishingThreadKey?: string) => void;
/** Called EARLY (at the stream's `start` chunk) with the authoritative server
* chat id streamed on the assistant message metadata, so a brand-new chat
* adopts its real id WHILE the first turn is still streaming (#174 — makes the
* Copy/export button available mid-stream). Distinct from onTurnFinished,
* which fires only at the terminal outcome. */
onServerChatId?: (serverChatId?: string) => void;
/** Reports the live turn-token total (reasoning + output) for the in-flight
* turn so the parent can show a header badge that ticks mid-stream. THROTTLED
* here (~8 Hz) so the parent re-renders a handful of times a second, not on
* every streamed delta. Called with `null` when no turn is in flight (the
* parent then reverts the badge to the persisted context size). */
onLiveTurnTokens?: (tokens: number | null) => void;
}
/**
* Map a persisted server row to an AI SDK UIMessage. Mirrors the server's
* `rowToUiMessage`: `metadata.parts` are the UIMessage parts; otherwise fall
* back to a single text part built from the plain-text `content`.
*/
function rowToUiMessage(row: IAiChatMessageRow): UIMessage {
const role = row.role === "assistant" ? "assistant" : "user";
const parts =
Array.isArray(row.metadata?.parts) && row.metadata.parts.length > 0
? row.metadata.parts
: ([{ type: "text", text: row.content ?? "" }] as UIMessage["parts"]);
const error = row.metadata?.error;
const finishReason = row.metadata?.finishReason;
const metadata: Record<string, unknown> = {};
if (error) metadata.error = error;
if (finishReason) metadata.finishReason = finishReason;
return {
id: row.id,
role,
parts,
// Carry persisted turn outcome (error text and/or finishReason) so MessageItem
// can render the error banner / "stopped" marker after a remount and in
// reopened history.
...(Object.keys(metadata).length > 0 ? { metadata } : {}),
} as UIMessage;
}
/**
* Owns the AI SDK `useChat` lifecycle for ONE chat. The parent remounts this
* with a `key` when the selected chat changes, so initial messages re-seed
* cleanly (the v6 transport-based hook keeps its state per mount).
*/
export default function ChatThread({
chatId,
threadKey,
initialRows,
openPage,
roleId,
roles,
onRolePicked,
assistantName,
onTurnFinished,
onServerChatId,
onLiveTurnTokens,
}: ChatThreadProps) {
const { t } = useTranslation();
const initialMessages = useMemo<UIMessage[]>(
() => (initialRows ?? []).map(rowToUiMessage),
[initialRows],
);
// The server resolves/creates the chat from the `chatId` in the request body.
// A new chat starts as null; we keep the id in a ref so the SAME hook instance
// can keep streaming to a chat once it exists (the parent adopts the id on
// finish, but within this mount the body carries whatever we know).
const chatIdRef = useRef<string | null>(chatId);
chatIdRef.current = chatId;
// Keep the currently-open page in a ref, updated each render, so the LATEST
// open page is sent on every send WITHOUT re-creating the `useMemo([])`-stable
// transport (and thus without re-creating the useChat store mid-stream — see
// the `chatStoreId` note below). Read live inside `prepareSendMessagesRequest`.
const openPageRef = useRef<OpenPageContext | null>(openPage ?? null);
openPageRef.current = openPage ?? null;
// Keep the selected role id in a ref, same rationale as openPageRef. Only the
// FIRST request of a brand-new chat uses it (the server persists it then and
// ignores it for existing chats), but sending it on every send is harmless.
const roleIdRef = useRef<string | null>(roleId ?? null);
roleIdRef.current = roleId ?? null;
// Stable `useChat` store key for the lifetime of THIS mount.
//
// CRITICAL: `useChat` (@ai-sdk/react) re-creates its internal `Chat` store
// whenever the `id` option no longer equals the store's current id
// (`"id" in options && chatRef.current.id !== options.id`). For a brand-new
// chat (`chatId === null`) we previously passed `id: undefined`; the store
// then generated its OWN random id internally, so `store.id !== undefined`
// stayed true on EVERY render and the store was re-created on every render —
// wiping the optimistic user message, the "submitted" status, and every
// streamed delta until the turn fully finished (then the parent adopts the
// new chat id and remounts with the persisted history, making everything
// "appear at once"). Passing a STABLE non-undefined id keeps one store for
// the whole turn, so the user message shows immediately and tokens stream
// live. This id is purely the client store key; the server still resolves the
// real chat from `chatId` in the request body (see `prepareSendMessagesRequest`).
// The id only needs to be stable per mount — the parent remounts this via
// `key` on chat switch, which re-seeds cleanly.
const stableIdRef = useRef<string>(chatId ?? `new-${generateId()}`);
// Stable for the LIFETIME of this mount. When a brand-new chat adopts its
// server id, the parent now updates the `chatId` prop WITHOUT remounting this
// thread, so the store id must NOT follow `chatId`: recreating the useChat
// store would wipe the live (just-finished) turn. The server still resolves
// the real chat from `chatId` in the request body (see chatIdRef /
// prepareSendMessagesRequest), so this purely-client store key can stay fixed.
const chatStoreId = stableIdRef.current;
// Pending messages the user composed WHILE a turn was streaming. They are sent
// automatically, FIFO, on successful turn completion (`onFinish`). The queue is
// LOCAL state so it is scoped to this conversation: it is cleared when the user
// deliberately switches chat / starts a new chat (the parent remounts this via
// `key`), but it SURVIVES in-place new-chat id adoption (no remount), so a
// message queued during a brand-new chat's first turn is not lost. On Stop or
// error the queue is intentionally preserved (onFinish does not fire then) so
// the user decides what to do with the pending messages.
const [queued, setQueued] = useState<QueuedMessage[]>([]);
// Mirror the queue in a ref so the `onFinish` flush always reads the latest
// queue without a stale closure; `setQueue` updates BOTH the ref and the state.
const queuedRef = useRef<QueuedMessage[]>([]);
const setQueue = useCallback((next: QueuedMessage[]) => {
queuedRef.current = next;
setQueued(next);
}, []);
// Capture the latest `sendMessage` (returned by useChat below) so the flush
// helper can call the current instance from the stable `onFinish` callback.
const sendMessageRef = useRef<((m: { text: string }) => void) | null>(null);
// FIFO dequeue + send the next queued message (no-op when the queue is empty).
const flushNext = useCallback(() => {
const { head, rest } = dequeue(queuedRef.current);
if (!head) return;
setQueue(rest);
sendMessageRef.current?.({ text: head.text });
}, [setQueue]);
const enqueue = useCallback(
(text: string) => {
setQueue(enqueueMessage(queuedRef.current, { id: generateId(), text }));
},
[setQueue],
);
const removeQueued = useCallback(
(id: string) => {
setQueue(removeQueuedById(queuedRef.current, id));
},
[setQueue],
);
const transport = useMemo(
() =>
new DefaultChatTransport<UIMessage>({
api: "/api/ai-chat/stream",
credentials: "include",
// Inject the chat id and the currently-open page alongside the useChat
// messages so the server can resolve an existing chat (or create one
// when null) and tell the agent which page "this page" refers to. Both
// are read live from refs so changing chats/pages does NOT recreate the
// transport. `openPage` is null on a non-page route.
prepareSendMessagesRequest: ({ messages, body }) => ({
body: {
...body,
chatId: chatIdRef.current,
openPage: openPageRef.current,
// Honoured by the server only when creating a new chat; null =>
// universal assistant.
roleId: roleIdRef.current,
messages,
},
}),
}),
[],
);
const { messages, sendMessage, status, stop, error } = useChat({
// Stable per-mount key. Existing chats use their real id; new chats use a
// generated client id (never `undefined`) so the store is NOT re-created on
// every render mid-stream (see `chatStoreId` above).
id: chatStoreId,
messages: initialMessages,
transport,
// `onFinish` (ai@6 useChat) fires from a `finally` on EVERY terminal outcome
// — success, user Stop/abort (`isAbort`), network drop (`isDisconnect`), and
// stream error (`isError`). Keep calling `onTurnFinished()` on all of them
// (chat-list refresh + new-chat id adoption must happen even on a failed
// first turn), but flush the pending queue ONLY on a clean finish: auto-
// sending after the user hit Stop — or blindly retrying after a failure —
// would be wrong, so on Stop/disconnect/error the queue is left intact for
// the user to decide.
onFinish: ({ message, isAbort, isDisconnect, isError }) => {
// Forward the authoritative server chatId (streamed on the assistant
// message metadata) so the parent adopts the REAL created chat id for a new
// chat — see adopt-chat-id.ts for the full #137 design. `threadKey` lets the
// session ignore this finish if it belongs to a thread abandoned by New chat
// mid-stream (#161).
onTurnFinished(extractServerChatId(message), threadKey);
// Show a neutral "stopped" marker for an aborted turn; the red error banner
// (via `error`) already covers isError, and a clean finish clears any marker.
if (isError) setStopNotice(null);
else if (isAbort) setStopNotice("manual");
else if (isDisconnect) setStopNotice("disconnect");
else setStopNotice(null);
if (isAbort || isDisconnect || isError) return;
flushNext();
},
// `onError` runs in addition to `onFinish` (which ai@6 also calls on error).
// Log the raw failure here for devtools; the UI shows a friendly classified
// banner via `error` below. We still call `onTurnFinished()` with NO server id
// (idempotent with the onFinish call): for a brand-new chat that ARMS the
// bounded list-refetch fallback (adopt the single newly-appeared chat once the
// refetch lands); for an existing chat it just refreshes the chat list
// immediately rather than after a manual refresh.
onError: (streamError) => {
// Surface the raw failure in the browser console (devtools) for debugging;
// the UI separately shows a friendly classified banner (see errorView).
console.error("AI chat stream error:", streamError);
onTurnFinished(undefined, threadKey);
},
});
// Keep the flush helper pointed at the latest sendMessage instance.
sendMessageRef.current = sendMessage;
// EARLY chat-id adoption (#174): the server streams the authoritative chat id
// on the assistant message metadata at the `start` chunk (message.metadata.
// chatId — see adopt-chat-id.ts / chatStreamMetadata). Forward it to the parent
// AS SOON AS it appears (mid-stream), so a brand-new chat adopts its real id
// WHILE the first turn is still streaming and activeChatId-gated affordances
// (the Copy/export button) light up immediately, instead of only at onFinish.
// Keyed by the last-seen id so we forward each distinct id exactly once. The
// parent's onServerChatId is idempotent and a no-op once the chat has an id.
const lastForwardedChatIdRef = useRef<string | undefined>(undefined);
useEffect(() => {
if (!onServerChatId) return;
const tail = messages[messages.length - 1];
if (tail?.role !== "assistant") return;
const serverChatId = extractServerChatId(tail);
if (!serverChatId || serverChatId === lastForwardedChatIdRef.current)
return;
lastForwardedChatIdRef.current = serverChatId;
onServerChatId(serverChatId);
}, [messages, onServerChatId]);
// Live "turn was interrupted" marker for the CURRENT session. The red error
// banner (driven by `error`) covers the error case; this covers an aborted
// turn, distinguishing a manual Stop (`isAbort`) from a dropped connection
// (`isDisconnect`) — a distinction only available live (the server persists
// both as finishReason 'aborted'). Cleared when the next turn starts.
const [stopNotice, setStopNotice] = useState<null | "manual" | "disconnect">(
null,
);
const isStreaming = status === "submitted" || status === "streaming";
// Clear the stopped marker as soon as a new turn begins streaming.
useEffect(() => {
if (isStreaming) setStopNotice(null);
}, [isStreaming]);
// Classify the turn error into a heading + detail so the banner names the cause
// (connection reset, timeout, rate limit, context overflow, quota, ...) instead
// of a generic "Something went wrong". Computed here (not only in the JSX) so
// the SAME on-screen banner text can be mirrored into the export (issue #160).
const errorView = error ? describeChatError(error.message ?? "", t) : null;
// Report the live turn-token total to the parent header badge, THROTTLED to
// ~8 Hz so the parent re-renders a few times a second instead of on every
// streamed delta. The tail assistant message's reasoning+output (estimate while
// streaming, authoritative once a step reports usage) is the live figure. When
// the turn ends we emit a final exact value, then `null` so the parent reverts
// the badge to the persisted context size.
const lastEmitRef = useRef(0);
const emitTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
useEffect(() => {
if (!onLiveTurnTokens) return;
if (!isStreaming) {
// Turn ended (or never started): clear any pending throttle and revert.
if (emitTimerRef.current) {
clearTimeout(emitTimerRef.current);
emitTimerRef.current = null;
}
lastEmitRef.current = 0;
onLiveTurnTokens(null);
return;
}
const tail = messages[messages.length - 1];
const live = tail?.role === "assistant" ? liveTurnTokens(tail) : null;
const total = live ? live.reasoning + live.output : 0;
const now = Date.now();
const MIN_INTERVAL = 120; // ms (~8 Hz)
const elapsed = now - lastEmitRef.current;
if (elapsed >= MIN_INTERVAL) {
lastEmitRef.current = now;
onLiveTurnTokens(total);
} else if (!emitTimerRef.current) {
// Schedule a trailing emit so the FINAL value of a burst is not dropped.
emitTimerRef.current = setTimeout(() => {
emitTimerRef.current = null;
lastEmitRef.current = Date.now();
onLiveTurnTokens(total);
}, MIN_INTERVAL - elapsed);
}
}, [messages, isStreaming, onLiveTurnTokens]);
// Clear any pending throttle timer on unmount (chat switch via `key`) so a
// trailing emit can't fire into a torn-down thread's parent.
useEffect(() => {
return () => {
if (emitTimerRef.current) clearTimeout(emitTimerRef.current);
};
}, []);
// A role was picked with autoStart=false: the role is bound but NOTHING was
// sent, so chatId stays null and the empty state would keep showing the cards.
// This flag hides the cards and reveals the composer (with the role indicated)
// so the user can type the first message themselves. roleIdRef is already set,
// so that first manual message carries the roleId.
const [rolePickedNoSend, setRolePickedNoSend] = useState(false);
// Clicking a role card always binds the role to THIS new chat. Whether it also
// auto-starts the conversation is per-role (autoStart). roleIdRef is set
// synchronously here because the parent's selectedRoleId state update would
// only reach roleIdRef on the next render — after this synchronous sendMessage
// has already read it.
const handleRolePick = (role: IAiRole): void => {
roleIdRef.current = role.id;
onRolePicked?.(role);
const launch = roleLaunchMessage(
role,
t("Take a look at the current document"),
);
if (launch !== null) {
sendMessage({ text: launch });
} else {
// autoStart=false -> bind only: hide the cards, show the composer.
setRolePickedNoSend(true);
}
};
// Reset the "picked, not sent" flag when the thread returns to a truly empty,
// role-less state — e.g. the user hit "New chat" after picking an autoStart=false
// role. That path clears the parent's selectedRoleId (roleId -> null) but leaves
// chatId null, so the thread never remounts and the flag would stay set, hiding
// the cards forever. A picked-and-bound role keeps roleId non-null, so the cards
// correctly stay hidden then. Render-phase reset (React "adjust state on prop
// change"): one-shot — it re-renders with the flag false and the guard no longer
// matches, so it cannot loop. (Review of #149.)
if (shouldResetRolePicked(chatId, roleId, rolePickedNoSend)) {
setRolePickedNoSend(false);
}
const showRoleCards =
chatId === null && (roles?.length ?? 0) > 0 && !rolePickedNoSend;
const roleCardsEmptyState = showRoleCards ? (
<RoleCards roles={roles ?? []} onPick={handleRolePick} />
) : undefined;
return (
<Box className={classes.panel}>
<MessageList
messages={messages}
isStreaming={isStreaming}
emptyState={roleCardsEmptyState}
assistantName={assistantName}
/>
{errorView ? (
<ChatErrorAlert
title={errorView.title}
detail={errorView.detail}
mb="xs"
/>
) : stopNotice ? (
<ChatStoppedNotice
text={
stopNotice === "manual"
? t("Response stopped.")
: t("Connection lost — the answer was interrupted.")
}
mb="xs"
/>
) : null}
<Stack gap={0} className={classes.inputWrapper}>
{queued.length > 0 && (
<Stack gap={4} className={classes.queuedList}>
{queued.map((m) => (
<Group
key={m.id}
gap={6}
wrap="nowrap"
className={classes.queuedItem}
>
<IconClockHour4 size={14} className={classes.queuedIcon} />
<Text size="xs" lineClamp={2} className={classes.queuedText}>
{m.text}
</Text>
<ActionIcon
size="xs"
variant="subtle"
color="gray"
onClick={() => removeQueued(m.id)}
aria-label={t("Remove queued message")}
>
<IconX size={12} />
</ActionIcon>
</Group>
))}
</Stack>
)}
<ChatInput
onSend={(text) => sendMessage({ text })}
onQueue={enqueue}
onStop={stop}
isStreaming={isStreaming}
/>
</Stack>
</Box>
);
}