import {
	ActionBarPrimitive,
	AssistantIf,
	BranchPickerPrimitive,
	ComposerPrimitive,
	ErrorPrimitive,
	MessagePrimitive,
	ThreadPrimitive,
	useAssistantState,
	useComposerRuntime,
} from "@assistant-ui/react";
import { useAtom, useAtomValue, useSetAtom } from "jotai";
import {
	AlertCircle,
	ArrowDownIcon,
	ArrowUpIcon,
	CheckIcon,
	ChevronLeftIcon,
	ChevronRightIcon,
	CopyIcon,
	Dot,
	DownloadIcon,
	FileWarning,
	Paperclip,
	RefreshCwIcon,
	SquareIcon,
} from "lucide-react";
import { useParams } from "next/navigation";
import { type FC, useCallback, useContext, useEffect, useMemo, useRef, useState } from "react";
import { createPortal } from "react-dom";
import { toast } from "sonner";
import { chatSessionStateAtom } from "@/atoms/chat/chat-session-state.atom";
import { showCommentsGutterAtom } from "@/atoms/chat/current-thread.atom";
import {
	mentionedDocumentIdsAtom,
	mentionedDocumentsAtom,
} from "@/atoms/chat/mentioned-documents.atom";
import { membersAtom } from "@/atoms/members/members-query.atoms";
import {
	globalNewLLMConfigsAtom,
	llmPreferencesAtom,
	newLLMConfigsAtom,
} from "@/atoms/new-llm-config/new-llm-config-query.atoms";
import { currentUserAtom } from "@/atoms/user/user-query.atoms";
import { AssistantMessage } from "@/components/assistant-ui/assistant-message";
import { ChatSessionStatus } from "@/components/assistant-ui/chat-session-status";
import { ConnectorIndicator } from "@/components/assistant-ui/connector-popup";
import {
	InlineMentionEditor,
	type InlineMentionEditorRef,
} from "@/components/assistant-ui/inline-mention-editor";
import { MarkdownText } from "@/components/assistant-ui/markdown-text";
import {
	ThinkingStepsContext,
	ThinkingStepsDisplay,
} from "@/components/assistant-ui/thinking-steps";
import { ToolFallback } from "@/components/assistant-ui/tool-fallback";
import { TooltipIconButton } from "@/components/assistant-ui/tooltip-icon-button";
import { UserMessage } from "@/components/assistant-ui/user-message";
import {
	DocumentMentionPicker,
	type DocumentMentionPickerRef,
} from "@/components/new-chat/document-mention-picker";
import type { ThinkingStep } from "@/components/tool-ui/deepagent-thinking";
import { Button } from "@/components/ui/button";
import { Spinner } from "@/components/ui/spinner";
import type { Document } from "@/contracts/types/document.types";
import { useBatchCommentsPreload } from "@/hooks/use-comments";
import { useCommentsElectric } from "@/hooks/use-comments-electric";
import { documentsApiService } from "@/lib/apis/documents-api.service";
import { cn } from "@/lib/utils";

/** Placeholder texts that cycle in new chats when input is empty */
const CYCLING_PLACEHOLDERS = [
	"Ask SurfSense anything or @mention docs.",
	"Generate a podcast from my vacation ideas in Notion.",
	"Sum up last week's meeting notes from Drive in a bulleted list.",
	"Give me a brief overview of the most urgent tickets in Jira and Linear.",
	"Briefly, what are today's top ten important emails and calendar events?",
	"Check if this week's Slack messages reference any GitHub issues.",
];

const CHAT_UPLOAD_ACCEPT =
	".pdf,.doc,.docx,.txt,.md,.markdown,.ppt,.pptx,.xls,.xlsx,.xlsm,.xlsb,.csv,.html,.htm,.xml,.rtf,.epub,.jpg,.jpeg,.png,.bmp,.webp,.tiff,.tif,.mp3,.mp4,.mpeg,.mpga,.m4a,.wav,.webm";

const CHAT_MAX_FILES = 10;
const CHAT_MAX_FILE_SIZE_BYTES = 50 * 1024 * 1024; // 50 MB per file
const CHAT_MAX_TOTAL_SIZE_BYTES = 200 * 1024 * 1024; // 200 MB total

type UploadState = "pending" | "processing" | "ready" | "failed";

interface UploadedMentionDoc {
	id: number;
	title: string;
	document_type: Document["document_type"];
	state: UploadState;
	reason?: string | null;
}

interface ThreadProps {
	messageThinkingSteps?: Map<string, ThinkingStep[]>;
	header?: React.ReactNode;
}

export const Thread: FC<ThreadProps> = ({ messageThinkingSteps = new Map(), header }) => {
	return (
		<ThinkingStepsContext.Provider value={messageThinkingSteps}>
			<ThreadContent header={header} />
		</ThinkingStepsContext.Provider>
	);
};

const ThreadContent: FC<{ header?: React.ReactNode }> = ({ header }) => {
	const showGutter = useAtomValue(showCommentsGutterAtom);

	return (
		<ThreadPrimitive.Root
			className="aui-root aui-thread-root @container flex h-full min-h-0 flex-col bg-background"
			style={{
				["--thread-max-width" as string]: "44rem",
			}}
		>
			<ThreadPrimitive.Viewport
				turnAnchor="top"
				autoScroll
				className={cn(
					"aui-thread-viewport relative flex flex-1 min-h-0 flex-col overflow-y-auto px-4 pt-4 transition-[padding] duration-300 ease-out",
					showGutter && "lg:pr-30"
				)}
			>
				{header && <div className="sticky top-0 z-10 mb-4">{header}</div>}

				<AssistantIf condition={({ thread }) => thread.isEmpty}>
					<ThreadWelcome />
				</AssistantIf>

				<ThreadPrimitive.Messages
					components={{
						UserMessage,
						EditComposer,
						AssistantMessage,
					}}
				/>

				<ThreadPrimitive.ViewportFooter
					className="aui-thread-viewport-footer sticky bottom-0 z-10 mx-auto mt-auto flex w-full max-w-(--thread-max-width) flex-col gap-4 overflow-visible rounded-t-3xl bg-background pb-4 md:pb-6"
					style={{ paddingBottom: "max(1rem, env(safe-area-inset-bottom))" }}
				>
					<ThreadScrollToBottom />
					<AssistantIf condition={({ thread }) => !thread.isEmpty}>
						<div className="fade-in slide-in-from-bottom-4 animate-in duration-500 ease-out fill-mode-both">
							<Composer />
						</div>
					</AssistantIf>
				</ThreadPrimitive.ViewportFooter>
			</ThreadPrimitive.Viewport>
		</ThreadPrimitive.Root>
	);
};

const ThreadScrollToBottom: FC = () => {
	return (
		<ThreadPrimitive.ScrollToBottom asChild>
			<TooltipIconButton
				tooltip="Scroll to bottom"
				variant="outline"
				className="aui-thread-scroll-to-bottom -top-12 absolute z-10 self-center rounded-full p-4 disabled:invisible dark:bg-background dark:hover:bg-accent"
			>
				<ArrowDownIcon />
			</TooltipIconButton>
		</ThreadPrimitive.ScrollToBottom>
	);
};

const getTimeBasedGreeting = (user?: { display_name?: string | null; email?: string }): string => {
	const hour = new Date().getHours();

	// Extract first name: prefer display_name, fall back to email extraction
	let firstName: string | null = null;

	if (user?.display_name?.trim()) {
		// Use display_name if available and not empty
		// Extract first name from display_name (take first word)
		const nameParts = user.display_name.trim().split(/\s+/);
		firstName = nameParts[0].charAt(0).toUpperCase() + nameParts[0].slice(1).toLowerCase();
	} else if (user?.email) {
		// Fall back to email extraction if display_name is not available
		firstName =
			user.email.split("@")[0].split(".")[0].charAt(0).toUpperCase() +
			user.email.split("@")[0].split(".")[0].slice(1);
	}

	// Array of greeting variations for each time period
	const morningGreetings = ["Good morning", "Fresh start today", "Morning", "Hey there"];

	const afternoonGreetings = ["Good afternoon", "Afternoon", "Hey there", "Hi there"];

	const eveningGreetings = ["Good evening", "Evening", "Hey there", "Hi there"];

	const nightGreetings = ["Good night", "Evening", "Hey there", "Winding down"];

	const lateNightGreetings = ["Still up", "Night owl mode", "Up past bedtime", "Hi there"];

	// Select a random greeting based on time
	let greeting: string;
	if (hour < 5) {
		// Late night: midnight to 5 AM
		greeting = lateNightGreetings[Math.floor(Math.random() * lateNightGreetings.length)];
	} else if (hour < 12) {
		greeting = morningGreetings[Math.floor(Math.random() * morningGreetings.length)];
	} else if (hour < 18) {
		greeting = afternoonGreetings[Math.floor(Math.random() * afternoonGreetings.length)];
	} else if (hour < 22) {
		greeting = eveningGreetings[Math.floor(Math.random() * eveningGreetings.length)];
	} else {
		// Night: 10 PM to midnight
		greeting = nightGreetings[Math.floor(Math.random() * nightGreetings.length)];
	}

	// Add personalization with first name if available
	if (firstName) {
		return `${greeting}, ${firstName}!`;
	}

	return `${greeting}!`;
};

const ThreadWelcome: FC = () => {
	const { data: user } = useAtomValue(currentUserAtom);

	// Memoize greeting so it doesn't change on re-renders (only on user change)
	const greeting = useMemo(() => getTimeBasedGreeting(user), [user]);

	return (
		<div className="aui-thread-welcome-root mx-auto flex w-full max-w-(--thread-max-width) grow flex-col items-center px-4 relative">
			{/* Greeting positioned above the composer - fixed position */}
			<div className="aui-thread-welcome-message absolute bottom-[calc(50%+5rem)] left-0 right-0 flex flex-col items-center text-center">
				<h1 className="aui-thread-welcome-message-inner fade-in slide-in-from-bottom-2 animate-in text-3xl md:text-5xl delay-100 duration-500 ease-out fill-mode-both">
					{greeting}
				</h1>
			</div>
			{/* Composer - top edge fixed, expands downward only */}
			<div className="fade-in slide-in-from-bottom-3 animate-in delay-200 duration-500 ease-out fill-mode-both w-full flex items-start justify-center absolute top-[calc(50%-3.5rem)] left-0 right-0">
				<Composer />
			</div>
		</div>
	);
};

const Composer: FC = () => {
	// Document mention state (atoms persist across component remounts)
	const [mentionedDocuments, setMentionedDocuments] = useAtom(mentionedDocumentsAtom);
	const [showDocumentPopover, setShowDocumentPopover] = useState(false);
	const [mentionQuery, setMentionQuery] = useState("");
	const [uploadedMentionDocs, setUploadedMentionDocs] = useState<
		Record<number, UploadedMentionDoc>
	>({});
	const [isUploadingDocs, setIsUploadingDocs] = useState(false);
	const editorRef = useRef<InlineMentionEditorRef>(null);
	const editorContainerRef = useRef<HTMLDivElement>(null);
	const uploadInputRef = useRef<HTMLInputElement>(null);
	const isFileDialogOpenRef = useRef(false);
	const documentPickerRef = useRef<DocumentMentionPickerRef>(null);
	const { search_space_id, chat_id } = useParams();
	const setMentionedDocumentIds = useSetAtom(mentionedDocumentIdsAtom);
	const composerRuntime = useComposerRuntime();
	const hasAutoFocusedRef = useRef(false);

	const isThreadEmpty = useAssistantState(({ thread }) => thread.isEmpty);
	const isThreadRunning = useAssistantState(({ thread }) => thread.isRunning);

	// Cycling placeholder state - only cycles in new chats
	const [placeholderIndex, setPlaceholderIndex] = useState(0);

	// Cycle through placeholders every 4 seconds when thread is empty (new chat)
	useEffect(() => {
		// Only cycle when thread is empty (new chat)
		if (!isThreadEmpty) {
			// Reset to first placeholder when chat becomes active
			setPlaceholderIndex(0);
			return;
		}

		const intervalId = setInterval(() => {
			setPlaceholderIndex((prev) => (prev + 1) % CYCLING_PLACEHOLDERS.length);
		}, 6000);

		return () => clearInterval(intervalId);
	}, [isThreadEmpty]);

	// Compute current placeholder - only cycle in new chats
	const currentPlaceholder = isThreadEmpty
		? CYCLING_PLACEHOLDERS[placeholderIndex]
		: CYCLING_PLACEHOLDERS[0];

	// Live collaboration state
	const { data: currentUser } = useAtomValue(currentUserAtom);
	const { data: members } = useAtomValue(membersAtom);
	const threadId = useMemo(() => {
		if (Array.isArray(chat_id) && chat_id.length > 0) {
			return Number.parseInt(chat_id[0], 10) || null;
		}
		return typeof chat_id === "string" ? Number.parseInt(chat_id, 10) || null : null;
	}, [chat_id]);
	const sessionState = useAtomValue(chatSessionStateAtom);
	const isAiResponding = sessionState?.isAiResponding ?? false;
	const respondingToUserId = sessionState?.respondingToUserId ?? null;
	const isBlockedByOtherUser = isAiResponding && respondingToUserId !== currentUser?.id;

	// Sync comments for the entire thread via Electric SQL (one subscription per thread)
	useCommentsElectric(threadId);

	// Batch-prefetch comments for all assistant messages so individual useComments
	// hooks never fire their own network requests (eliminates N+1 API calls).
	// Return a primitive string from the selector so useSyncExternalStore can
	// compare snapshots by value and avoid infinite re-render loops.
	const assistantIdsKey = useAssistantState(({ thread }) =>
		thread.messages
			.filter((m) => m.role === "assistant" && m.id?.startsWith("msg-"))
			.map((m) => m.id!.replace("msg-", ""))
			.join(",")
	);
	const assistantDbMessageIds = useMemo(
		() => (assistantIdsKey ? assistantIdsKey.split(",").map(Number) : []),
		[assistantIdsKey]
	);
	useBatchCommentsPreload(assistantDbMessageIds);

	// Auto-focus editor on new chat page after mount
	useEffect(() => {
		if (isThreadEmpty && !hasAutoFocusedRef.current && editorRef.current) {
			const timeoutId = setTimeout(() => {
				editorRef.current?.focus();
				hasAutoFocusedRef.current = true;
			}, 100);
			return () => clearTimeout(timeoutId);
		}
	}, [isThreadEmpty]);

	// Sync mentioned document IDs to atom for inclusion in chat request payload
	useEffect(() => {
		setMentionedDocumentIds({
			surfsense_doc_ids: mentionedDocuments
				.filter((doc) => doc.document_type === "SURFSENSE_DOCS")
				.map((doc) => doc.id),
			document_ids: mentionedDocuments
				.filter((doc) => doc.document_type !== "SURFSENSE_DOCS")
				.map((doc) => doc.id),
		});
	}, [mentionedDocuments, setMentionedDocumentIds]);

	// Sync editor text with assistant-ui composer runtime
	const handleEditorChange = useCallback(
		(text: string) => {
			composerRuntime.setText(text);
		},
		[composerRuntime]
	);

	// Open document picker when @ mention is triggered
	const handleMentionTrigger = useCallback((query: string) => {
		setShowDocumentPopover(true);
		setMentionQuery(query);
	}, []);

	// Close document picker and reset query
	const handleMentionClose = useCallback(() => {
		if (showDocumentPopover) {
			setShowDocumentPopover(false);
			setMentionQuery("");
		}
	}, [showDocumentPopover]);

	// Keyboard navigation for document picker (arrow keys, Enter, Escape)
	const handleKeyDown = useCallback(
		(e: React.KeyboardEvent) => {
			if (showDocumentPopover) {
				if (e.key === "ArrowDown") {
					e.preventDefault();
					documentPickerRef.current?.moveDown();
					return;
				}
				if (e.key === "ArrowUp") {
					e.preventDefault();
					documentPickerRef.current?.moveUp();
					return;
				}
				if (e.key === "Enter") {
					e.preventDefault();
					documentPickerRef.current?.selectHighlighted();
					return;
				}
				if (e.key === "Escape") {
					e.preventDefault();
					setShowDocumentPopover(false);
					setMentionQuery("");
					return;
				}
			}
		},
		[showDocumentPopover]
	);

	const uploadedMentionedDocs = useMemo(
		() => mentionedDocuments.filter((doc) => uploadedMentionDocs[doc.id]),
		[mentionedDocuments, uploadedMentionDocs]
	);

	const blockingUploadedMentions = useMemo(
		() =>
			uploadedMentionedDocs.filter((doc) => {
				const state = uploadedMentionDocs[doc.id]?.state;
				return state === "pending" || state === "processing" || state === "failed";
			}),
		[uploadedMentionedDocs, uploadedMentionDocs]
	);

	// Submit message (blocked during streaming, document picker open, or AI responding to another user)
	const handleSubmit = useCallback(() => {
		if (
			isThreadRunning ||
			isBlockedByOtherUser ||
			isUploadingDocs ||
			blockingUploadedMentions.length > 0
		) {
			return;
		}
		if (!showDocumentPopover) {
			composerRuntime.send();
			editorRef.current?.clear();
			setMentionedDocuments([]);
			setMentionedDocumentIds({
				surfsense_doc_ids: [],
				document_ids: [],
			});
		}
	}, [
		showDocumentPopover,
		isThreadRunning,
		isBlockedByOtherUser,
		isUploadingDocs,
		blockingUploadedMentions.length,
		composerRuntime,
		setMentionedDocuments,
		setMentionedDocumentIds,
	]);

	// Remove document from mentions and sync IDs to atom
	const handleDocumentRemove = useCallback(
		(docId: number, docType?: string) => {
			setMentionedDocuments((prev) => {
				const updated = prev.filter((doc) => !(doc.id === docId && doc.document_type === docType));
				setMentionedDocumentIds({
					surfsense_doc_ids: updated
						.filter((doc) => doc.document_type === "SURFSENSE_DOCS")
						.map((doc) => doc.id),
					document_ids: updated
						.filter((doc) => doc.document_type !== "SURFSENSE_DOCS")
						.map((doc) => doc.id),
				});
				return updated;
			});
			setUploadedMentionDocs((prev) => {
				if (!(docId in prev)) return prev;
				const { [docId]: _removed, ...rest } = prev;
				return rest;
			});
		},
		[setMentionedDocuments, setMentionedDocumentIds]
	);

	// Add selected documents from picker, insert chips, and sync IDs to atom
	const handleDocumentsMention = useCallback(
		(documents: Pick<Document, "id" | "title" | "document_type">[]) => {
			const existingKeys = new Set(mentionedDocuments.map((d) => `${d.document_type}:${d.id}`));
			const newDocs = documents.filter(
				(doc) => !existingKeys.has(`${doc.document_type}:${doc.id}`)
			);

			for (const doc of newDocs) {
				editorRef.current?.insertDocumentChip(doc);
			}

			setMentionedDocuments((prev) => {
				const existingKeySet = new Set(prev.map((d) => `${d.document_type}:${d.id}`));
				const uniqueNewDocs = documents.filter(
					(doc) => !existingKeySet.has(`${doc.document_type}:${doc.id}`)
				);
				const updated = [...prev, ...uniqueNewDocs];
				setMentionedDocumentIds({
					surfsense_doc_ids: updated
						.filter((doc) => doc.document_type === "SURFSENSE_DOCS")
						.map((doc) => doc.id),
					document_ids: updated
						.filter((doc) => doc.document_type !== "SURFSENSE_DOCS")
						.map((doc) => doc.id),
				});
				return updated;
			});

			setMentionQuery("");
		},
		[mentionedDocuments, setMentionedDocuments, setMentionedDocumentIds]
	);

	const refreshUploadedDocStatuses = useCallback(
		async (documentIds: number[]) => {
			if (!search_space_id || documentIds.length === 0) return;
			const statusResponse = await documentsApiService.getDocumentsStatus({
				queryParams: {
					search_space_id: Number(search_space_id),
					document_ids: documentIds,
				},
			});

			setUploadedMentionDocs((prev) => {
				const next = { ...prev };
				for (const item of statusResponse.items) {
					next[item.id] = {
						id: item.id,
						title: item.title,
						document_type: item.document_type,
						state: item.status.state,
						reason: item.status.reason,
					};
				}
				return next;
			});

			handleDocumentsMention(
				statusResponse.items.map((item) => ({
					id: item.id,
					title: item.title,
					document_type: item.document_type,
				}))
			);
		},
		[search_space_id, handleDocumentsMention]
	);

	const handleUploadClick = useCallback(() => {
		if (isFileDialogOpenRef.current) return;
		isFileDialogOpenRef.current = true;
		uploadInputRef.current?.click();
		// Reset after a delay to handle cancellation (which doesn't fire the change event).
		setTimeout(() => {
			isFileDialogOpenRef.current = false;
		}, 1000);
	}, []);

	const handleUploadInputChange = useCallback(
		async (event: React.ChangeEvent<HTMLInputElement>) => {
			isFileDialogOpenRef.current = false;
			const files = Array.from(event.target.files ?? []);
			event.target.value = "";
			if (files.length === 0 || !search_space_id) return;

			if (files.length > CHAT_MAX_FILES) {
				toast.error(`Too many files. Maximum ${CHAT_MAX_FILES} files per upload.`);
				return;
			}

			let totalSize = 0;
			for (const file of files) {
				if (file.size > CHAT_MAX_FILE_SIZE_BYTES) {
					toast.error(
						`File "${file.name}" (${(file.size / (1024 * 1024)).toFixed(1)} MB) exceeds the ${CHAT_MAX_FILE_SIZE_BYTES / (1024 * 1024)} MB per-file limit.`
					);
					return;
				}
				totalSize += file.size;
			}
			if (totalSize > CHAT_MAX_TOTAL_SIZE_BYTES) {
				toast.error(
					`Total upload size (${(totalSize / (1024 * 1024)).toFixed(1)} MB) exceeds the ${CHAT_MAX_TOTAL_SIZE_BYTES / (1024 * 1024)} MB limit.`
				);
				return;
			}

			setIsUploadingDocs(true);
			try {
				const uploadResponse = await documentsApiService.uploadDocument({
					files,
					search_space_id: Number(search_space_id),
				});
				const uploadedIds = uploadResponse.document_ids ?? [];
				const duplicateIds = uploadResponse.duplicate_document_ids ?? [];
				const idsToMention = Array.from(new Set([...uploadedIds, ...duplicateIds]));
				if (idsToMention.length === 0) {
					toast.warning("No documents were created or matched from selected files.");
					return;
				}

				await refreshUploadedDocStatuses(idsToMention);
				if (uploadedIds.length > 0 && duplicateIds.length > 0) {
					toast.success(
						`Uploaded ${uploadedIds.length} file${uploadedIds.length > 1 ? "s" : ""} and matched ${duplicateIds.length} existing file${duplicateIds.length > 1 ? "s" : ""}.`
					);
				} else if (uploadedIds.length > 0) {
					toast.success(`Uploaded ${uploadedIds.length} file${uploadedIds.length > 1 ? "s" : ""}`);
				} else {
					toast.success(
						`Matched ${duplicateIds.length} existing file${duplicateIds.length > 1 ? "s" : ""} and added mention${duplicateIds.length > 1 ? "s" : ""}.`
					);
				}
			} catch (error) {
				const message = error instanceof Error ? error.message : "Upload failed";
				toast.error(`Upload failed: ${message}`);
			} finally {
				setIsUploadingDocs(false);
			}
		},
		[search_space_id, refreshUploadedDocStatuses]
	);

	// Poll status for uploaded mentioned documents until all are ready or removed.
	useEffect(() => {
		const trackedIds = uploadedMentionedDocs.map((doc) => doc.id);
		const needsPolling = trackedIds.some((id) => {
			const state = uploadedMentionDocs[id]?.state;
			return state === "pending" || state === "processing";
		});
		if (!needsPolling) return;

		const interval = setInterval(() => {
			refreshUploadedDocStatuses(trackedIds).catch((error) => {
				console.error("[Composer] Failed to refresh uploaded mention statuses:", error);
			});
		}, 2500);

		return () => clearInterval(interval);
	}, [uploadedMentionedDocs, uploadedMentionDocs, refreshUploadedDocStatuses]);

	// Push upload status directly onto mention chips (instead of separate status rows).
	useEffect(() => {
		for (const doc of uploadedMentionedDocs) {
			const state = uploadedMentionDocs[doc.id]?.state ?? "pending";
			const statusLabel =
				state === "ready"
					? null
					: state === "failed"
						? "failed"
						: state === "processing"
							? "indexing"
							: "queued";
			editorRef.current?.setDocumentChipStatus(doc.id, doc.document_type, statusLabel, state);
		}
	}, [uploadedMentionedDocs, uploadedMentionDocs]);

	// Prune upload status entries that are no longer mentioned in the composer.
	useEffect(() => {
		const activeIds = new Set(mentionedDocuments.map((doc) => doc.id));
		setUploadedMentionDocs((prev) => {
			let changed = false;
			const next: Record<number, UploadedMentionDoc> = {};
			for (const [key, value] of Object.entries(prev)) {
				const id = Number(key);
				if (activeIds.has(id)) {
					next[id] = value;
				} else {
					changed = true;
				}
			}
			return changed ? next : prev;
		});
	}, [mentionedDocuments]);

	return (
		<ComposerPrimitive.Root className="aui-composer-root relative flex w-full flex-col gap-2">
			<ChatSessionStatus
				isAiResponding={isAiResponding}
				respondingToUserId={respondingToUserId}
				currentUserId={currentUser?.id ?? null}
				members={members ?? []}
			/>
			<div className="aui-composer-attachment-dropzone flex w-full flex-col rounded-2xl border-input bg-muted px-1 pt-2 outline-none transition-shadow">
				{/* Inline editor with @mention support */}
				<div ref={editorContainerRef} className="aui-composer-input-wrapper px-3 pt-3 pb-6">
					<InlineMentionEditor
						ref={editorRef}
						placeholder={currentPlaceholder}
						onMentionTrigger={handleMentionTrigger}
						onMentionClose={handleMentionClose}
						onChange={handleEditorChange}
						onDocumentRemove={handleDocumentRemove}
						onSubmit={handleSubmit}
						onKeyDown={handleKeyDown}
						className="min-h-[24px]"
					/>
				</div>
				<input
					ref={uploadInputRef}
					type="file"
					multiple
					accept={CHAT_UPLOAD_ACCEPT}
					onChange={handleUploadInputChange}
					className="hidden"
				/>

				{/* Document picker popover (portal to body for proper z-index stacking) */}
				{showDocumentPopover &&
					typeof document !== "undefined" &&
					createPortal(
						<DocumentMentionPicker
							ref={documentPickerRef}
							searchSpaceId={Number(search_space_id)}
							onSelectionChange={handleDocumentsMention}
							onDone={() => {
								setShowDocumentPopover(false);
								setMentionQuery("");
							}}
							initialSelectedDocuments={mentionedDocuments}
							externalSearch={mentionQuery}
							containerStyle={{
								bottom: editorContainerRef.current
									? `${window.innerHeight - editorContainerRef.current.getBoundingClientRect().top + 8}px`
									: "200px",
								left: editorContainerRef.current
									? `${editorContainerRef.current.getBoundingClientRect().left}px`
									: "50%",
							}}
						/>,
						document.body
					)}
				<ComposerAction
					isBlockedByOtherUser={isBlockedByOtherUser}
					onUploadClick={handleUploadClick}
					isUploadingDocs={isUploadingDocs}
					blockingUploadedMentionsCount={blockingUploadedMentions.length}
					hasFailedUploadedMentions={blockingUploadedMentions.some(
						(doc) => uploadedMentionDocs[doc.id]?.state === "failed"
					)}
				/>
			</div>
		</ComposerPrimitive.Root>
	);
};

interface ComposerActionProps {
	isBlockedByOtherUser?: boolean;
	onUploadClick: () => void;
	isUploadingDocs: boolean;
	blockingUploadedMentionsCount: number;
	hasFailedUploadedMentions: boolean;
}

const ComposerAction: FC<ComposerActionProps> = ({
	isBlockedByOtherUser = false,
	onUploadClick,
	isUploadingDocs,
	blockingUploadedMentionsCount,
	hasFailedUploadedMentions,
}) => {
	const mentionedDocuments = useAtomValue(mentionedDocumentsAtom);

	// Check if composer text is empty (chips are represented in mentionedDocuments atom)
	const isComposerTextEmpty = useAssistantState(({ composer }) => {
		const text = composer.text?.trim() || "";
		return text.length === 0;
	});
	const isComposerEmpty = isComposerTextEmpty && mentionedDocuments.length === 0;

	// Check if a model is configured
	const { data: userConfigs } = useAtomValue(newLLMConfigsAtom);
	const { data: globalConfigs } = useAtomValue(globalNewLLMConfigsAtom);
	const { data: preferences } = useAtomValue(llmPreferencesAtom);

	const hasModelConfigured = useMemo(() => {
		if (!preferences) return false;
		const agentLlmId = preferences.agent_llm_id;
		if (agentLlmId === null || agentLlmId === undefined) return false;

		// Check if the configured model actually exists
		// Auto mode (ID 0) and global configs (negative IDs) are in globalConfigs
		if (agentLlmId <= 0) {
			return globalConfigs?.some((c) => c.id === agentLlmId) ?? false;
		}
		return userConfigs?.some((c) => c.id === agentLlmId) ?? false;
	}, [preferences, globalConfigs, userConfigs]);

	const isSendDisabled =
		isComposerEmpty ||
		!hasModelConfigured ||
		isBlockedByOtherUser ||
		isUploadingDocs ||
		blockingUploadedMentionsCount > 0;

	return (
		<div className="aui-composer-action-wrapper relative mx-2 mb-2 flex items-center justify-between">
			<div className="flex items-center gap-1">
				<TooltipIconButton
					tooltip={
						isUploadingDocs ? (
							"Uploading documents..."
						) : (
							<div className="flex flex-col gap-0.5">
								<span className="font-medium">Upload and mention files</span>
								<span className="text-xs text-muted-foreground flex items-center">
									Max 10 files <Dot className="size-3" /> 50 MB each
								</span>
								<span className="text-xs text-muted-foreground">Total upload limit: 200 MB</span>
							</div>
						)
					}
					side="bottom"
					variant="ghost"
					size="icon"
					className="size-[34px] rounded-full p-1 font-semibold text-xs hover:bg-muted-foreground/15 dark:border-muted-foreground/15 dark:hover:bg-muted-foreground/30"
					aria-label="Upload files"
					onClick={onUploadClick}
					disabled={isUploadingDocs}
				>
					{isUploadingDocs ? (
						<Spinner size="sm" className="text-muted-foreground" />
					) : (
						<Paperclip className="size-4" />
					)}
				</TooltipIconButton>
				<ConnectorIndicator />
			</div>

			{blockingUploadedMentionsCount > 0 && (
				<div className="flex items-center gap-1.5 text-muted-foreground text-xs">
					{hasFailedUploadedMentions ? <FileWarning className="size-3" /> : <Spinner size="xs" />}
					<span>
						{hasFailedUploadedMentions
							? "Remove or retry failed uploads"
							: "Waiting for uploaded files to finish indexing"}
					</span>
				</div>
			)}

			{/* Show warning when no model is configured */}
			{!hasModelConfigured && blockingUploadedMentionsCount === 0 && (
				<div className="flex items-center gap-1.5 text-amber-600 dark:text-amber-400 text-xs">
					<AlertCircle className="size-3" />
					<span>Select a model</span>
				</div>
			)}

			<AssistantIf condition={({ thread }) => !thread.isRunning}>
				<ComposerPrimitive.Send asChild disabled={isSendDisabled}>
					<TooltipIconButton
						tooltip={
							isBlockedByOtherUser
								? "Wait for AI to finish responding"
								: hasFailedUploadedMentions
									? "Remove or retry failed uploads before sending"
									: blockingUploadedMentionsCount > 0
										? "Waiting for uploaded files to finish indexing"
										: isUploadingDocs
											? "Uploading documents..."
											: !hasModelConfigured
												? "Please select a model from the header to start chatting"
												: isComposerEmpty
													? "Enter a message to send"
													: "Send message"
						}
						side="bottom"
						type="submit"
						variant="default"
						size="icon"
						className={cn(
							"aui-composer-send size-8 rounded-full",
							isSendDisabled && "cursor-not-allowed opacity-50"
						)}
						aria-label="Send message"
						disabled={isSendDisabled}
					>
						<ArrowUpIcon className="aui-composer-send-icon size-4" />
					</TooltipIconButton>
				</ComposerPrimitive.Send>
			</AssistantIf>

			<AssistantIf condition={({ thread }) => thread.isRunning}>
				<ComposerPrimitive.Cancel asChild>
					<Button
						type="button"
						variant="default"
						size="icon"
						className="aui-composer-cancel size-8 rounded-full"
						aria-label="Stop generating"
					>
						<SquareIcon className="aui-composer-cancel-icon size-3 fill-current" />
					</Button>
				</ComposerPrimitive.Cancel>
			</AssistantIf>
		</div>
	);
};

const MessageError: FC = () => {
	return (
		<MessagePrimitive.Error>
			<ErrorPrimitive.Root className="aui-message-error-root mt-2 rounded-md border border-destructive bg-destructive/10 p-3 text-destructive text-sm dark:bg-destructive/5 dark:text-red-200">
				<ErrorPrimitive.Message className="aui-message-error-message line-clamp-2" />
			</ErrorPrimitive.Root>
		</MessagePrimitive.Error>
	);
};

/**
 * Custom component to render thinking steps from Context
 */
const ThinkingStepsPart: FC = () => {
	const thinkingStepsMap = useContext(ThinkingStepsContext);

	// Get the current message ID to look up thinking steps
	const messageId = useAssistantState(({ message }) => message?.id);
	const thinkingSteps = thinkingStepsMap.get(messageId) || [];

	// Check if this specific message is currently streaming
	// A message is streaming if: thread is running AND this is the last assistant message
	const isThreadRunning = useAssistantState(({ thread }) => thread.isRunning);
	const isLastMessage = useAssistantState(({ message }) => message?.isLast ?? false);
	const isMessageStreaming = isThreadRunning && isLastMessage;

	if (thinkingSteps.length === 0) return null;

	return (
		<div className="mb-3">
			<ThinkingStepsDisplay steps={thinkingSteps} isThreadRunning={isMessageStreaming} />
		</div>
	);
};

const AssistantMessageInner: FC = () => {
	return (
		<>
			{/* Render thinking steps from message content - this ensures proper scroll tracking */}
			<ThinkingStepsPart />

			<div className="aui-assistant-message-content wrap-break-word px-2 text-foreground leading-relaxed">
				<MessagePrimitive.Parts
					components={{
						Text: MarkdownText,
						tools: { Fallback: ToolFallback },
					}}
				/>
				<MessageError />
			</div>

			<div className="aui-assistant-message-footer mt-1 mb-5 ml-2 flex">
				<BranchPicker />
				<AssistantActionBar />
			</div>
		</>
	);
};

const AssistantActionBar: FC = () => {
	return (
		<ActionBarPrimitive.Root
			hideWhenRunning
			autohide="not-last"
			autohideFloat="single-branch"
			className="aui-assistant-action-bar-root -ml-1 col-start-3 row-start-2 flex gap-1 text-muted-foreground data-floating:absolute data-floating:rounded-md data-floating:border data-floating:bg-background data-floating:p-1 data-floating:shadow-sm"
		>
			<ActionBarPrimitive.Copy asChild>
				<TooltipIconButton tooltip="Copy">
					<AssistantIf condition={({ message }) => message.isCopied}>
						<CheckIcon />
					</AssistantIf>
					<AssistantIf condition={({ message }) => !message.isCopied}>
						<CopyIcon />
					</AssistantIf>
				</TooltipIconButton>
			</ActionBarPrimitive.Copy>
			<ActionBarPrimitive.ExportMarkdown asChild>
				<TooltipIconButton tooltip="Export as Markdown">
					<DownloadIcon />
				</TooltipIconButton>
			</ActionBarPrimitive.ExportMarkdown>
			<ActionBarPrimitive.Reload asChild>
				<TooltipIconButton tooltip="Refresh">
					<RefreshCwIcon />
				</TooltipIconButton>
			</ActionBarPrimitive.Reload>
		</ActionBarPrimitive.Root>
	);
};

const EditComposer: FC = () => {
	return (
		<MessagePrimitive.Root className="aui-edit-composer-wrapper mx-auto flex w-full max-w-(--thread-max-width) flex-col px-2 py-3">
			<ComposerPrimitive.Root className="aui-edit-composer-root ml-auto flex w-full max-w-[85%] flex-col rounded-2xl bg-muted">
				<ComposerPrimitive.Input
					className="aui-edit-composer-input min-h-14 w-full resize-none bg-transparent p-4 text-foreground text-sm outline-none"
					autoFocus
				/>
				<div className="aui-edit-composer-footer mx-3 mb-3 flex items-center gap-2 self-end">
					<ComposerPrimitive.Cancel asChild>
						<Button variant="ghost" size="sm">
							Cancel
						</Button>
					</ComposerPrimitive.Cancel>
					<ComposerPrimitive.Send asChild>
						<Button size="sm">Update</Button>
					</ComposerPrimitive.Send>
				</div>
			</ComposerPrimitive.Root>
		</MessagePrimitive.Root>
	);
};

const BranchPicker: FC<BranchPickerPrimitive.Root.Props> = ({ className, ...rest }) => {
	return (
		<BranchPickerPrimitive.Root
			hideWhenSingleBranch
			className={cn(
				"aui-branch-picker-root -ml-2 mr-2 inline-flex items-center text-muted-foreground text-xs",
				className
			)}
			{...rest}
		>
			<BranchPickerPrimitive.Previous asChild>
				<TooltipIconButton tooltip="Previous">
					<ChevronLeftIcon />
				</TooltipIconButton>
			</BranchPickerPrimitive.Previous>
			<span className="aui-branch-picker-state font-medium">
				<BranchPickerPrimitive.Number /> / <BranchPickerPrimitive.Count />
			</span>
			<BranchPickerPrimitive.Next asChild>
				<TooltipIconButton tooltip="Next">
					<ChevronRightIcon />
				</TooltipIconButton>
			</BranchPickerPrimitive.Next>
		</BranchPickerPrimitive.Root>
	);
};