import { useQuery } from "@tanstack/react-query";
import { useRouter } from "expo-router";
import React, { useState } from "react";
import { Linking, ScrollView, Switch, Text, View } from "react-native";
import { useApp } from "../src/app-context";
import { AppHeader } from "../src/components/AppHeader";
import { ChatInputBar } from "../src/components/ChatInputBar";
import { HanLogo } from "../src/components/HanLogo";
import { PopularQuestionsList } from "../src/components/PopularQuestionsList";
import { QuickActions } from "../src/components/QuickActions";
import { ScreenShell } from "../src/components/ScreenShell";
import {
  clearPendingTextIntent,
  createPendingTextIntent,
  savePendingTextIntent,
  type PendingTextIntent,
} from "../src/pending-intent";
import { dialogApi, publicApi, uploadAttachment } from "../src/services";
import type { Consents } from "../src/types";
import { Button, 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 [required, setRequired] = useState({ personal: false, agreement: false, marketing: false });
  const [pending, setPending] = useState<PendingTextIntent | null>(null);
  const [message, setMessage] = useState("");
  const [sendError, setSendError] = useState<unknown>();
  const [sending, setSending] = useState(false);
  const router = useRouter();

  const sendAuthenticated = async (intent: PendingTextIntent) => {
    setSending(true);
    setSendError(undefined);
    try {
      const dialog = await dialogApi.create(intent.dialogKey);
      await dialogApi.sendText(dialog.dialog_id, intent.text, intent.messageKey);
      setMessage("");
      setPending(null);
      clearPendingTextIntent();
      router.push(`/dialogs/${dialog.dialog_id}`);
    } catch (error) {
      setSendError(error);
    } finally {
      setSending(false);
    }
  };

  const send = async (text: string) => {
    const normalized = text.trim();
    if (!normalized) return;
    if (normalized.length > 4000) {
      setSendError(new Error("Сообщение слишком длинное. Максимум — 4000 символов."));
      return;
    }
    const intent = createPendingTextIntent(normalized);
    if (authStatus !== "authenticated") {
      setPending(intent);
      savePendingTextIntent(intent);
      setConsentOpen(true);
      return;
    }
    await sendAuthenticated(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;
    }
    setSending(true);
    setSendError(undefined);
    try {
      const dialog = await dialogApi.create(crypto.randomUUID());
      const uploaded = await uploadAttachment(dialog.dialog_id, file);
      await dialogApi.sendFile(
        dialog.dialog_id,
        uploaded.attachmentId,
        uploaded.checksum,
        crypto.randomUUID(),
      );
      router.push(`/dialogs/${dialog.dialog_id}`);
    } catch (error) {
      setSendError(error);
    } finally {
      setSending(false);
    }
  };

  const accept = async () => {
    if (!required.personal || !required.agreement) return;
    const versions = config.data?.consents;
    const consents: Consents = {
      personal_data: { accepted: true, version: versions?.personal_data?.version ?? "current" },
      user_agreement: { accepted: true, version: versions?.user_agreement?.version ?? "current" },
      marketing: { accepted: required.marketing, version: versions?.marketing?.version ?? "current" },
    };
    setConsentOpen(false);
    try {
      const authorized = await authorize(consents);
      if (authorized && pending) await sendAuthenticated(pending);
    } catch (error) {
      setSendError(error);
    }
  };

  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}
        </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}
        />
        <QuickActions phone={config.data?.operator.call_phone} />
        {sendError && (
          <View style={{ paddingHorizontal: 16, paddingBottom: 8 }}>
            <ErrorNotice error={sendError} />
          </View>
        )}
      </View>

      {consentOpen && (
        <View accessibilityViewIsModal style={styles.modalBackdrop}>
          <View style={styles.modal}>
            <Text accessibilityRole="header" style={styles.heading}>Согласия перед входом</Text>
            <Text style={styles.text}>Для отправки сообщения или файла необходимо войти по номеру телефона. Код вводится только на защищённой странице авторизации.</Text>
            {(["personal_data", "user_agreement", "marketing"] as const).map((key) => {
              const item = config.data?.consents?.[key];
              if (!item) return null;
              return item.document_url ? (
                <Text key={key} accessibilityRole="link" style={styles.link} onPress={() => void Linking.openURL(item.document_url!)}>
                  {key === "personal_data" ? "Политика персональных данных" : key === "user_agreement" ? "Пользовательское соглашение" : "Согласие на рекламу"} · версия {item.version}
                </Text>
              ) : null;
            })}
            <ConsentRow label="Обработка персональных данных (обязательно)" value={required.personal} onChange={(personal) => setRequired({ ...required, personal })} />
            <ConsentRow label="Пользовательское соглашение (обязательно)" value={required.agreement} onChange={(agreement) => setRequired({ ...required, agreement })} />
            <ConsentRow label="Рекламные коммуникации (необязательно)" value={required.marketing} onChange={(marketing) => setRequired({ ...required, marketing })} />
            <View style={styles.row}>
              <Button title="Продолжить" disabled={!required.personal || !required.agreement} onPress={() => void accept()} />
              <Button
                title="Отмена"
                secondary
                onPress={() => {
                  setConsentOpen(false);
                  setPending(null);
                  clearPendingTextIntent();
                }}
              />
            </View>
          </View>
        </View>
      )}
    </ScreenShell>
  );
}

const spacing = 16;

function ConsentRow({ label, value, onChange }: { label: string; value: boolean; onChange: (value: boolean) => void }) {
  return <View style={[styles.row, { justifyContent: "space-between" }]}>
    <Text style={[styles.text, { flex: 1 }]}>{label}</Text>
    <Switch accessibilityLabel={label} value={value} onValueChange={onChange} />
  </View>;
}