import { useQuery } from "@tanstack/react-query";
import { useLocalSearchParams, useRouter } from "expo-router";
import React, { useEffect, useRef, useState } from "react";
import { ScrollView, Text, View } from "react-native";
import { useApp } from "../src/app-context";
import { AppHeader } from "../src/components/AppHeader";
import { ChatInputBar } from "../src/components/ChatInputBar";
import { ConsentModal } from "../src/components/ConsentModal";
import { HanLogo } from "../src/components/HanLogo";
import { NotificationCarousel } from "../src/components/NotificationCarousel";
import { PopularQuestionsList } from "../src/components/PopularQuestionsList";
import { QuickActions } from "../src/components/QuickActions";
import { ScreenShell } from "../src/components/ScreenShell";
import {
  clearPendingTextIntent,
  createPendingTextIntent,
  savePendingTextIntent,
  savePendingFileIntent,
  type PendingTextIntent,
} from "../src/pending-intent";
import { DEFAULT_MESSAGE_MAX_LENGTH, normalizeMessageText } from "../src/message-text";
import { publicApi } from "../src/services";
import type { Consents } from "../src/types";
import { ErrorNotice, Loading, styles } from "../src/ui";

export default function HomeScreen() {
  const { authStatus, authorize } = useApp();
  const config = useQuery({ queryKey: ["public-config"], queryFn: publicApi.config });
  const content = useQuery({ queryKey: ["public-content"], queryFn: publicApi.content });
  const [consentOpen, setConsentOpen] = useState(false);
  const [pending, setPending] = useState<PendingTextIntent | null>(null);
  const [message, setMessage] = useState("");
  const [sendError, setSendError] = useState<unknown>();
  const [sending] = useState(false);
  const [afterNotificationAuth, setAfterNotificationAuth] = useState<(() => Promise<void>) | undefined>();
  const { authorize: authorizeParam } = useLocalSearchParams<{ authorize?: string }>();
  const handledAuthorizeParam = useRef(false);
  const router = useRouter();

  useEffect(() => {
    if (authorizeParam === "1" && !handledAuthorizeParam.current && authStatus !== "authenticated") {
      handledAuthorizeParam.current = true;
      setConsentOpen(true);
    }
  }, [authStatus, authorizeParam]);

  const openChatWithText = (intent: PendingTextIntent) => {
    setSendError(undefined);
    savePendingTextIntent(intent);
    setMessage("");
    setPending(null);
    router.push("/dialogs?pending=1");
  };

  const send = async (text: string) => {
    const normalized = normalizeMessageText(text);
    if (!normalized) return;
    const maxLength = config.data?.messages?.max_text_length ?? DEFAULT_MESSAGE_MAX_LENGTH;
    if (normalized.length > maxLength) {
      setSendError(new Error(`Сообщение слишком длинное. Максимум — ${maxLength} символов.`));
      return;
    }
    const intent = createPendingTextIntent(normalized);
    if (authStatus !== "authenticated") {
      setPending(intent);
      savePendingTextIntent(intent);
      setConsentOpen(true);
      return;
    }
    openChatWithText(intent);
  };

  const chooseFile = () => {
    if (authStatus !== "authenticated") {
      setConsentOpen(true);
      return;
    }
    if (typeof document === "undefined") {
      setSendError(new Error("Выбор файла в этой сборке доступен только в web."));
      return;
    }
    const input = document.createElement("input");
    input.type = "file";
    input.accept = "image/*,application/pdf";
    input.onchange = () => {
      const file = input.files?.[0];
      if (file) void sendFile(file);
    };
    input.click();
  };

  const sendFile = async (file: File) => {
    const limits = config.data?.attachments;
    const max = (limits?.max_size_mb ?? 5) * 1024 * 1024;
    const allowed = limits?.allowed_mime_types ?? ["image/jpeg", "image/png", "image/webp", "application/pdf"];
    if (file.size > max || !allowed.includes(file.type)) {
      setSendError(new Error("Недопустимый тип файла или превышен допустимый размер."));
      return;
    }
    setSendError(undefined);
    savePendingFileIntent({
      file,
      dialogKey: crypto.randomUUID(),
      messageKey: crypto.randomUUID(),
    });
    router.push("/dialogs?pending=1");
  };

  const accept = async (accepted: {
    personal_data: boolean;
    user_agreement: boolean;
    marketing: boolean;
  }) => {
    const versions = config.data?.consents;
    const consents: Consents = {
      personal_data: { accepted: accepted.personal_data, version: versions?.personal_data?.version ?? "current" },
      user_agreement: { accepted: accepted.user_agreement, version: versions?.user_agreement?.version ?? "current" },
      marketing: { accepted: accepted.marketing, version: versions?.marketing?.version ?? "current" },
    };
    setConsentOpen(false);
    try {
      const authorized = await authorize(consents);
      if (authorized && pending) openChatWithText(pending);
      else if (authorized && afterNotificationAuth) await afterNotificationAuth();
    } catch (error) {
      setSendError(error);
    } finally {
      setAfterNotificationAuth(undefined);
    }
  };

  const welcome = content.data?.texts.welcome;
  const questions = content.data?.popular_questions ?? [];

  return (
    <ScreenShell>
      <AppHeader guestLabel={authStatus === "authenticated" ? undefined : "Гость"} />
      <View style={{ flex: 1 }}>
        <HanLogo />
        <ScrollView style={{ flex: 1 }} contentContainerStyle={{ paddingBottom: spacing }}>
          {(config.isLoading || content.isLoading) && <Loading />}
          {(config.error || content.error) && (
            <View style={{ paddingHorizontal: 16 }}>
              <ErrorNotice error={config.error ?? content.error} retry={() => { void config.refetch(); void content.refetch(); }} />
            </View>
          )}
          {welcome ? (
            <Text style={[styles.muted, { paddingHorizontal: 16, marginBottom: 8 }]}>{welcome}</Text>
          ) : null}
          <NotificationCarousel
            authenticated={authStatus === "authenticated"}
            autoplay={config.data?.notification?.carousel_autoplay_enabled ?? false}
            autoplayIntervalMs={config.data?.notification?.carousel_autoplay_interval_ms ?? 5000}
            requireAuth={(afterAuth) => {
              setAfterNotificationAuth(afterAuth ? () => afterAuth : undefined);
              setConsentOpen(true);
            }}
          />
        </ScrollView>
        <PopularQuestionsList questions={questions} onSelect={(text) => { setMessage(text); void send(text); }} />
        <ChatInputBar
          disabled={sending}
          onAttach={chooseFile}
          onChangeText={setMessage}
          onSubmit={() => void send(message)}
          sending={sending}
          value={message}
          maxLength={config.data?.messages?.max_text_length ?? DEFAULT_MESSAGE_MAX_LENGTH}
        />
        <QuickActions
          authenticated={authStatus === "authenticated"}
          phone={config.data?.operator.call_phone}
        />
        {Boolean(sendError) && (
          <View style={{ paddingHorizontal: 16, paddingBottom: 8 }}>
            <ErrorNotice error={sendError} />
          </View>
        )}
      </View>

      {consentOpen && (
        <ConsentModal
          consents={config.data?.consents}
          onAccept={(accepted) => void accept(accepted)}
          onCancel={() => {
            setConsentOpen(false);
            setPending(null);
            setAfterNotificationAuth(undefined);
            clearPendingTextIntent();
          }}
        />
      )}
    </ScreenShell>
  );
}

const spacing = 16;