import {
	ActionBarPrimitive,
	AssistantIf,
	BranchPickerPrimitive,
	ComposerPrimitive,
	ErrorPrimitive,
	MessagePrimitive,
	ThreadPrimitive,
	useAssistantState,
} from "@assistant-ui/react";
import {
	ArrowDownIcon,
	ArrowUpIcon,
	CheckIcon,
	ChevronLeftIcon,
	ChevronRightIcon,
	CopyIcon,
	DownloadIcon,
	Loader2,
	PencilIcon,
	RefreshCwIcon,
	SquareIcon,
} from "lucide-react";
import type { FC } from "react";
import {
	ComposerAddAttachment,
	ComposerAttachments,
	UserMessageAttachments,
} from "@/components/assistant-ui/attachment";
import { MarkdownText } from "@/components/assistant-ui/markdown-text";
import { ToolFallback } from "@/components/assistant-ui/tool-fallback";
import { TooltipIconButton } from "@/components/assistant-ui/tooltip-icon-button";
import { Button } from "@/components/ui/button";
import { cn } from "@/lib/utils";

export const Thread: FC = () => {
	return (
		<ThreadPrimitive.Root
			className="aui-root aui-thread-root @container flex h-full flex-col bg-background"
			style={{
				["--thread-max-width" as string]: "44rem",
			}}
		>
			<ThreadPrimitive.Viewport
				turnAnchor="top"
				className="aui-thread-viewport relative flex flex-1 flex-col overflow-x-auto overflow-y-scroll scroll-smooth px-4 pt-4"
			>
				<AssistantIf condition={({ thread }) => thread.isEmpty}>
					<ThreadWelcome />
				</AssistantIf>

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

				<ThreadPrimitive.ViewportFooter className="aui-thread-viewport-footer sticky bottom-0 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">
					<ThreadScrollToBottom />
					<Composer />
				</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 ThreadWelcome: FC = () => {
	return (
		<div className="aui-thread-welcome-root mx-auto my-auto flex w-full max-w-(--thread-max-width) grow flex-col">
			<div className="aui-thread-welcome-center flex w-full grow flex-col items-center justify-center">
				<div className="aui-thread-welcome-message flex size-full flex-col justify-center px-4">
					<h1 className="aui-thread-welcome-message-inner fade-in slide-in-from-bottom-1 animate-in font-semibold text-2xl duration-200">
						Hello there!
					</h1>
					<p className="aui-thread-welcome-message-inner fade-in slide-in-from-bottom-1 animate-in text-muted-foreground text-xl delay-75 duration-200">
						How can I help you today?
					</p>
				</div>
			</div>
			<ThreadSuggestions />
		</div>
	);
};

const SUGGESTIONS = [
	{
		title: "What's the weather",
		label: "in San Francisco?",
		prompt: "What's the weather in San Francisco?",
	},
	{
		title: "Explain React hooks",
		label: "like useState and useEffect",
		prompt: "Explain React hooks like useState and useEffect",
	},
] as const;

const ThreadSuggestions: FC = () => {
	return (
		<div className="aui-thread-welcome-suggestions grid w-full @md:grid-cols-2 gap-2 pb-4">
			{SUGGESTIONS.map((suggestion, index) => (
				<div
					key={suggestion.prompt}
					className="aui-thread-welcome-suggestion-display fade-in slide-in-from-bottom-2 @md:nth-[n+3]:block nth-[n+3]:hidden animate-in fill-mode-both duration-200"
					style={{ animationDelay: `${100 + index * 50}ms` }}
				>
					<ThreadPrimitive.Suggestion prompt={suggestion.prompt} autoSend asChild>
						<Button
							variant="ghost"
							className="aui-thread-welcome-suggestion h-auto w-full @md:flex-col flex-wrap items-start justify-start gap-1 rounded-2xl border px-4 py-3 text-left text-sm transition-colors hover:bg-muted"
							aria-label={suggestion.prompt}
						>
							<span className="aui-thread-welcome-suggestion-text-1 font-medium">
								{suggestion.title}
							</span>
							<span className="aui-thread-welcome-suggestion-text-2 text-muted-foreground">
								{suggestion.label}
							</span>
						</Button>
					</ThreadPrimitive.Suggestion>
				</div>
			))}
		</div>
	);
};

const Composer: FC = () => {
	return (
		<ComposerPrimitive.Root className="aui-composer-root relative flex w-full flex-col">
			<ComposerPrimitive.AttachmentDropzone className="aui-composer-attachment-dropzone flex w-full flex-col rounded-2xl border border-input bg-background px-1 pt-2 outline-none transition-shadow has-[textarea:focus-visible]:border-ring has-[textarea:focus-visible]:ring-2 has-[textarea:focus-visible]:ring-ring/20 data-[dragging=true]:border-ring data-[dragging=true]:border-dashed data-[dragging=true]:bg-accent/50">
				<ComposerAttachments />
				<ComposerPrimitive.Input
					placeholder="Send a message..."
					className="aui-composer-input mb-1 max-h-32 min-h-14 w-full resize-none bg-transparent px-4 pt-2 pb-3 text-sm outline-none placeholder:text-muted-foreground focus-visible:ring-0"
					rows={1}
					autoFocus
					aria-label="Message input"
				/>
				<ComposerAction />
			</ComposerPrimitive.AttachmentDropzone>
		</ComposerPrimitive.Root>
	);
};

const ComposerAction: FC = () => {
	// Check if any attachments are still being processed (running AND progress < 100)
	// When progress is 100, processing is done but waiting for send()
	const hasProcessingAttachments = useAssistantState(({ composer }) =>
		composer.attachments?.some((att) => {
			const status = att.status;
			if (status?.type !== "running") return false;
			const progress = (status as { type: "running"; progress?: number }).progress;
			return progress === undefined || progress < 100;
		})
	);

	return (
		<div className="aui-composer-action-wrapper relative mx-2 mb-2 flex items-center justify-between">
			<ComposerAddAttachment />

			{/* Show processing indicator when attachments are being processed */}
			{hasProcessingAttachments && (
				<div className="flex items-center gap-1.5 text-muted-foreground text-xs">
					<Loader2 className="size-3 animate-spin" />
					<span>Processing...</span>
				</div>
			)}

			<AssistantIf condition={({ thread }) => !thread.isRunning}>
				<ComposerPrimitive.Send asChild disabled={hasProcessingAttachments}>
					<TooltipIconButton
						tooltip={hasProcessingAttachments ? "Wait for attachments to process" : "Send message"}
						side="bottom"
						type="submit"
						variant="default"
						size="icon"
						className={cn(
							"aui-composer-send size-8 rounded-full",
							hasProcessingAttachments && "cursor-not-allowed opacity-50"
						)}
						aria-label="Send message"
						disabled={hasProcessingAttachments}
					>
						<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>
	);
};

const AssistantMessage: FC = () => {
	return (
		<MessagePrimitive.Root
			className="aui-assistant-message-root fade-in slide-in-from-bottom-1 relative mx-auto w-full max-w-(--thread-max-width) animate-in py-3 duration-150"
			data-role="assistant"
		>
			<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 ml-2 flex">
				<BranchPicker />
				<AssistantActionBar />
			</div>
		</MessagePrimitive.Root>
	);
};

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 UserMessage: FC = () => {
	return (
		<MessagePrimitive.Root
			className="aui-user-message-root fade-in slide-in-from-bottom-1 mx-auto grid w-full max-w-(--thread-max-width) animate-in auto-rows-auto grid-cols-[minmax(72px,1fr)_auto] content-start gap-y-2 px-2 py-3 duration-150 [&:where(>*)]:col-start-2"
			data-role="user"
		>
			<UserMessageAttachments />

			<div className="aui-user-message-content-wrapper relative col-start-2 min-w-0">
				<div className="aui-user-message-content wrap-break-word rounded-2xl bg-muted px-4 py-2.5 text-foreground">
					<MessagePrimitive.Parts />
				</div>
				<div className="aui-user-action-bar-wrapper -translate-x-full -translate-y-1/2 absolute top-1/2 left-0 pr-2">
					<UserActionBar />
				</div>
			</div>

			<BranchPicker className="aui-user-branch-picker -mr-1 col-span-full col-start-1 row-start-3 justify-end" />
		</MessagePrimitive.Root>
	);
};

const UserActionBar: FC = () => {
	return (
		<ActionBarPrimitive.Root
			hideWhenRunning
			autohide="not-last"
			className="aui-user-action-bar-root flex flex-col items-end"
		>
			<ActionBarPrimitive.Edit asChild>
				<TooltipIconButton tooltip="Edit" className="aui-user-action-edit p-4">
					<PencilIcon />
				</TooltipIconButton>
			</ActionBarPrimitive.Edit>
		</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>
	);
};