import { cookies } from "next/headers";
import { redirect } from "next/navigation";
import { Suspense } from "react";
import { Chat } from "@/components/chat";
import { DataStreamHandler } from "@/components/data-stream-handler";
import { LovartHome } from "@/components/home/lovart-home";
import { generateUUID } from "@/lib/utils";
import { auth } from "../(auth)/auth";
import {
  getDefaultAiModel,
  getEnabledAiModelsWithProvider,
  getUserById,
  getSiteSettings,
  getSystemSetting,
} from "@/lib/db/queries";
import { isAiModelAgentAuto } from "@/lib/db/ai-model-flags";
import { isVideoModelDescriptor } from "@/lib/ai/model-classification";

function isNanoBananaProModel(model: { displayName?: string | null; modelId?: string | null }) {
  const displayName = String(model.displayName || "").toLowerCase();
  const modelId = String(model.modelId || "").toLowerCase();
  return (
    displayName.includes("nano banana pro") ||
    displayName.includes("nano-banana-pro") ||
    modelId.includes("nano-banana-pro") ||
    modelId.includes("nano_banana_pro") ||
    modelId.includes("nano-banana")
  );
}

export default function Page() {
  return (
    <Suspense fallback={<div className="flex h-dvh" />}>
      <NewChatPage />
    </Suspense>
  );
}

async function NewChatPage() {
  const id = generateUUID();

  const [session, cookieStore, siteSettings, homeVariantSetting, surpriseCategoriesSetting] =
    await Promise.all([
      auth(),
      cookies(),
      getSiteSettings(),
      getSystemSetting({ key: "home_variant" }).catch(() => undefined),
      getSystemSetting({ key: "home_surprise_categories" }).catch(() => undefined),
    ]);
  
  const homeVariant = homeVariantSetting?.value === "lovart" ? "lovart" : "classic";
  const surpriseCategories = Array.isArray(surpriseCategoriesSetting?.value)
    ? surpriseCategoriesSetting?.value
        .map((item: unknown) => String(item || "").trim())
        .filter(Boolean)
    : ["全部", "精选"];

  if (!session?.user && homeVariant !== "lovart") {
    redirect("/login");
  }

  if (homeVariant === "lovart") {
    return (
      <LovartHome
        user={
          session?.user
            ? {
                id: session.user.id,
                email: session.user.email,
                name: session.user.name,
                type: session.user.type,
              }
            : null
        }
        isAuthenticated={Boolean(session?.user)}
        siteName={siteSettings.siteName || "AI Chatbot"}
        siteLogo={siteSettings.siteLogo || siteSettings.siteLogoDark || ""}
        surpriseCategories={surpriseCategories}
        heroPromoText={siteSettings.lovartPromoText}
        heroPromoActionText={siteSettings.lovartPromoActionText}
        heroTitleText={siteSettings.lovartHeroTitle}
        heroSubtitleText={siteSettings.lovartHeroSubtitle}
      />
    );
  }
  
  const modelIdFromCookie = cookieStore.get("chat-model");

  let initialModelId = modelIdFromCookie?.value;
  const currentUser = session?.user?.id
    ? await getUserById({ id: session.user.id }).catch(() => undefined)
    : undefined;
  const allowHiddenModels =
    session?.user?.type === "admin" || Boolean(currentUser?.isHighVip);
  const defaultModel = await getDefaultAiModel();
  const enabledModels = await getEnabledAiModelsWithProvider(false, true);
  const visibleModels = enabledModels.filter(
    ({ model }) =>
      !isAiModelAgentAuto(model) &&
      (allowHiddenModels || !model.isHidden)
  );
  const preferredImageModels = visibleModels.filter(
    ({ model, provider }) =>
      model.supportsImageGen &&
      !isVideoModelDescriptor({
        providerType: provider.type,
        modelId: model.modelId,
        capabilities: model.capabilities,
        supportsImageGen: model.supportsImageGen,
      })
  );
  const nanoBananaModel = preferredImageModels.find(({ model }) =>
    isNanoBananaProModel(model)
  );
  const cookieModel = initialModelId
    ? visibleModels.find(({ model }) => model.id === initialModelId)
    : undefined;

  if (
    !initialModelId ||
    !cookieModel
  ) {
    if (nanoBananaModel) {
      initialModelId = nanoBananaModel.model.id;
    } else if (
      defaultModel &&
      !isAiModelAgentAuto(defaultModel) &&
      (allowHiddenModels || !defaultModel.isHidden) &&
      preferredImageModels.some(({ model }) => model.id === defaultModel.id)
    ) {
      initialModelId = defaultModel.id;
    } else if (preferredImageModels.length > 0) {
      const preferredDefaultImageModel = preferredImageModels.find(
        ({ model }) => model.isDefault
      );
      initialModelId = (preferredDefaultImageModel || preferredImageModels[0]).model.id;
    } else if (
      defaultModel &&
      !isAiModelAgentAuto(defaultModel) &&
      (allowHiddenModels || !defaultModel.isHidden)
    ) {
      initialModelId = defaultModel.id;
    } else if (visibleModels.length > 0) {
      initialModelId = visibleModels[0].model.id;
    }
  }

  return (
    <>
      <Chat
        autoResume={false}
        id={id}
        initialChatModel={initialModelId || ""}
        initialMessages={[]}
        initialVisibilityType="private"
        isReadonly={false}
        key={id}
        userType={session?.user?.type}
      />
      <DataStreamHandler />
    </>
  );
}