'use client';

import { DefaultChatTransport } from 'ai';
import { useChat } from '@ai-sdk/react';
import { useEffect, useState, useRef } from 'react';
import useSWR, { useSWRConfig } from 'swr';
import { ChatHeader } from '@/components/chat-header';
import type { Vote } from '@/lib/db/schema';
import { fetcher, fetchWithErrorHandlers, generateUUID } from '@/lib/utils';
import { Artifact } from './artifact';
import { MultimodalInput } from './multimodal-input';
import { Messages } from './messages';
import type { VisibilityType } from './visibility-selector';
import { useArtifactSelector } from '@/hooks/use-artifact';
import { unstable_serialize } from 'swr/infinite';
import { getChatHistoryPaginationKey } from './sidebar-history';
import { toast } from './toast';
import type { Session } from 'next-auth';
import { useSearchParams } from 'next/navigation';
import { useChatVisibility } from '@/hooks/use-chat-visibility';
import { useAutoResume } from '@/hooks/use-auto-resume';
import { ChatSDKError } from '@/lib/errors';
import type { Attachment, ChatMessage } from '@/lib/types';
import type { AppUsage } from '@/lib/usage';
import { useDataStream } from './data-stream-provider';
import {
  AlertDialog,
  AlertDialogAction,
  AlertDialogCancel,
  AlertDialogContent,
  AlertDialogDescription,
  AlertDialogFooter,
  AlertDialogHeader,
  AlertDialogTitle,
} from '@/components/ui/alert-dialog';

export function Chat({
  id,
  initialMessages,
  initialChatModel,
  initialVisibilityType,
  isReadonly,
  session,
  autoResume,
  initialLastContext,
}: {
  id: string;
  initialMessages: ChatMessage[];
  initialChatModel: string;
  initialVisibilityType: VisibilityType;
  isReadonly: boolean;
  session: Session;
  autoResume: boolean;
  initialLastContext?: AppUsage;
}) {
  const { visibilityType } = useChatVisibility({
    chatId: id,
    initialVisibilityType,
  });

  const { mutate } = useSWRConfig();
  const { setDataStream } = useDataStream();

  const [input, setInput] = useState<string>('');
  const [usage, setUsage] = useState<AppUsage | undefined>(initialLastContext);
  const [showCreditCardAlert, setShowCreditCardAlert] = useState(false);
  const [currentModelId, setCurrentModelId] = useState(initialChatModel);
  const currentModelIdRef = useRef(currentModelId);
  
  useEffect(() => {
    currentModelIdRef.current = currentModelId;
  }, [currentModelId]);

  const {
    messages,
    setMessages,
    sendMessage,
    status,
    stop,
    regenerate,
    resumeStream,
  } = useChat<ChatMessage>({
    id,
    messages: initialMessages,
    experimental_throttle: 100,
    generateId: generateUUID,
    transport: new DefaultChatTransport({
      api: '/api/chat',
      fetch: fetchWithErrorHandlers,
      prepareSendMessagesRequest({ messages, id, body }) {
        return {
          body: {
            id,
            message: messages.at(-1),
            selectedChatModel: currentModelIdRef.current,
            selectedVisibilityType: visibilityType,
            ...body,
          },
        };
      },
    }),
    onData: (dataPart) => {
      setDataStream((ds) => (ds ? [...ds, dataPart] : []));
      if (dataPart.type === 'data-usage') setUsage(dataPart.data);
    },
    onFinish: () => {
      mutate(unstable_serialize(getChatHistoryPaginationKey));
    },
    onError: (error) => {
      if (error instanceof ChatSDKError) {
        // Check if it's a credit card error
        if (
          error.message?.includes('AI Gateway requires a valid credit card')
        ) {
          setShowCreditCardAlert(true);
        } else {
          toast({
            type: 'error',
            description: error.message,
          });
        }
      }
    },
  });

  const searchParams = useSearchParams();
  const query = searchParams.get('query');

  const [hasAppendedQuery, setHasAppendedQuery] = useState(false);

  useEffect(() => {
    if (query && !hasAppendedQuery) {
      sendMessage({
        role: 'user' as const,
        parts: [{ type: 'text', text: query }],
      });

      setHasAppendedQuery(true);
      window.history.replaceState({}, '', `/chat/${id}`);
    }
  }, [query, sendMessage, hasAppendedQuery, id]);

  const { data: votes } = useSWR<Array<Vote>>(
    messages.length >= 2 ? `/api/vote?chatId=${id}` : null,
    fetcher,
  );

  const [attachments, setAttachments] = useState<Array<Attachment>>([]);
  const isArtifactVisible = useArtifactSelector((state) => state.isVisible);

  useAutoResume({
    autoResume,
    initialMessages,
    resumeStream,
    setMessages,
  });

  return (
    <>
      <div className="overscroll-behavior-contain flex h-dvh min-w-0 touch-pan-y flex-col bg-background">
        <ChatHeader
          chatId={id}
          selectedVisibilityType={initialVisibilityType}
          isReadonly={isReadonly}
          session={session}
        />

        <Messages
          chatId={id}
          status={status}
          votes={votes}
          messages={messages}
          setMessages={setMessages}
          regenerate={regenerate}
          isReadonly={isReadonly}
          isArtifactVisible={isArtifactVisible}
          selectedModelId={initialChatModel}
        />

        <div className="sticky bottom-0 z-1 mx-auto flex w-full max-w-4xl gap-2 border-t-0 bg-background px-2 pb-3 md:px-4 md:pb-4">
          {!isReadonly && (
            <MultimodalInput
              chatId={id}
              input={input}
              setInput={setInput}
              status={status}
              stop={stop}
              attachments={attachments}
              setAttachments={setAttachments}
              messages={messages}
              setMessages={setMessages}
              sendMessage={sendMessage}
              selectedVisibilityType={visibilityType}
              selectedModelId={currentModelId}
              onModelChange={setCurrentModelId}
              usage={usage}
            />
          )}
        </div>
      </div>

      <Artifact
        chatId={id}
        input={input}
        setInput={setInput}
        status={status}
        stop={stop}
        attachments={attachments}
        setAttachments={setAttachments}
        sendMessage={sendMessage}
        messages={messages}
        setMessages={setMessages}
        regenerate={regenerate}
        votes={votes}
        isReadonly={isReadonly}
        selectedVisibilityType={visibilityType}
        selectedModelId={currentModelId}
      />

      <AlertDialog
        open={showCreditCardAlert}
        onOpenChange={setShowCreditCardAlert}
      >
        <AlertDialogContent>
          <AlertDialogHeader>
            <AlertDialogTitle>Activate AI Gateway</AlertDialogTitle>
            <AlertDialogDescription>
              This application requires{' '}
              {process.env.NODE_ENV === 'production' ? 'the owner' : 'you'} to
              activate Vercel AI Gateway.
            </AlertDialogDescription>
          </AlertDialogHeader>
          <AlertDialogFooter>
            <AlertDialogCancel>Cancel</AlertDialogCancel>
            <AlertDialogAction
              onClick={() => {
                window.open(
                  'https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dadd-credit-card',
                  '_blank',
                );
                window.location.href = '/';
              }}
            >
              Activate
            </AlertDialogAction>
          </AlertDialogFooter>
        </AlertDialogContent>
      </AlertDialog>
    </>
  );
}