import { useAuthStore } from "@/src/stores/auth.store";
import { signOut } from "@/src/lib/auth-client";
import {
  useHouseholdMembers,
  useRevokeInvitation,
  type PendingInvitation,
  type HouseholdMember,
} from "@/src/hooks/useHouseholdMembers";
import { useHouseholdSettings, useUpdateHouseholdSettings } from "@/src/hooks/useHouseholdSettings";
import { ModalHeader } from "@/src/components/ui/ModalHeader";
import { useGenerateInviteCode } from "@/src/hooks/useInvite";
import { useQueryClient } from "@tanstack/react-query";
import { useRouter } from "expo-router";
import { useState, useEffect } from "react";
import {
  View,
  Text,
  Pressable,
  ScrollView,
  ToastAndroid,
  Platform,
  Alert,
  Modal,
  Share,
  ActivityIndicator,
} from "react-native";
import { useSafeAreaInsets } from "react-native-safe-area-context";
import { Ionicons } from "@expo/vector-icons";
import { useTranslation } from "react-i18next";
import i18n from "@/src/i18n";
import * as Localization from "expo-localization";

function showToast(message: string) {
  if (Platform.OS === "android") {
    ToastAndroid.show(message, ToastAndroid.SHORT);
  } else {
    Alert.alert("", message, [{ text: "OK" }], { cancelable: true });
  }
}

// ── Invite Code Modal ──────────────────────────────────────────────────────────

function InviteCodeModal({
  visible,
  onClose,
}: {
  visible: boolean;
  onClose: () => void;
}) {
  const { t } = useTranslation();
  const { mutate: generate, data, isPending, reset } = useGenerateInviteCode();
  const [copied, setCopied] = useState(false);

  useEffect(() => {
    if (visible) {
      reset();
      setCopied(false);
      generate();
    }
  }, [visible]);

  const code = data?.code ?? "";

  async function handleShare() {
    if (!code) return;
    await Share.share({ message: t('invite.shareText', { code }) });
  }

  async function handleCopy() {
    if (!code) return;
    await Share.share({ message: code });
    setCopied(true);
    setTimeout(() => setCopied(false), 2000);
  }

  function handleClose() {
    reset();
    setCopied(false);
    onClose();
  }

  return (
    <Modal
      visible={visible}
      animationType="slide"
      presentationStyle="pageSheet"
      onRequestClose={handleClose}
    >
      <View className="flex-1 bg-white">
        <ModalHeader
          title={t('invite.title')}
          onClose={handleClose}
          closeLabel={t('common.cancel')}
        />

        <View className="flex-1 items-center justify-center px-6">
          {isPending ? (
            <View className="items-center gap-3">
              <ActivityIndicator size="large" color="#2563EB" />
              <Text className="text-sm text-gray-400">{t('invite.generating')}</Text>
            </View>
          ) : (
            <>
              {/* Code display */}
              <View className="items-center mb-2 rounded-2xl bg-gray-50 px-8 py-6">
                <Text
                  style={{
                    fontSize: 40,
                    fontWeight: "700",
                    letterSpacing: 10,
                    color: "#111827",
                  }}
                >
                  {code || "------"}
                </Text>
              </View>

              <Text className="text-sm text-gray-400 mb-10">{t('invite.validFor')}</Text>

              {/* Copy button */}
              <Pressable
                onPress={handleCopy}
                className="w-full mb-3 flex-row items-center justify-center gap-2 rounded-xl bg-blue-600 py-4 active:opacity-80"
              >
                <Ionicons name="copy-outline" size={18} color="white" />
                <Text className="text-base font-semibold text-white">
                  {copied ? t('invite.copied') : t('invite.copyCode')}
                </Text>
              </Pressable>

              {/* Share button */}
              <Pressable
                onPress={handleShare}
                className="w-full mb-8 flex-row items-center justify-center gap-2 rounded-xl border border-blue-200 py-4 active:opacity-80"
              >
                <Ionicons name="share-outline" size={18} color="#2563EB" />
                <Text className="text-base font-semibold text-blue-600">{t('invite.share')}</Text>
              </Pressable>

              {/* Regenerate link */}
              <Pressable onPress={() => { setCopied(false); generate(); }} className="active:opacity-60">
                <Text className="text-sm text-gray-400 underline">{t('invite.newCode')}</Text>
              </Pressable>
            </>
          )}
        </View>
      </View>
    </Modal>
  );
}

// ── Members Section ────────────────────────────────────────────────────────────

function MembersSection() {
  const [showInviteModal, setShowInviteModal] = useState(false);
  const { data, isLoading } = useHouseholdMembers();
  const { mutate: revoke } = useRevokeInvitation();
  const currentUserId = useAuthStore((s) => s.user?.id);
  const { t } = useTranslation();

  function handleRevoke(inv: PendingInvitation) {
    Alert.alert(
      t('settings.revokeTitle'),
      t('settings.revokeMessage', { email: inv.email }),
      [
        { text: t('common.cancel'), style: "cancel" },
        {
          text: t('settings.revoke'),
          style: "destructive",
          onPress: () => revoke(inv.id, { onSuccess: () => showToast(t('settings.revokeSuccess')) }),
        },
      ],
    );
  }

  return (
    <>
      <View className="mb-6 rounded-xl bg-white p-4">
        <Text className="text-xs font-medium uppercase text-gray-400 mb-3">{t('settings.members')}</Text>

        {isLoading && (
          <ActivityIndicator size="small" color="#2563EB" style={{ marginVertical: 8 }} />
        )}

        {/* Active members */}
        {data?.members.map((m: HouseholdMember) => (
          <View
            key={m.userId}
            className="flex-row items-center justify-between py-3 border-b border-gray-100"
          >
            <View className="flex-row items-center gap-3">
              <View
                className="w-8 h-8 rounded-full items-center justify-center"
                style={{ backgroundColor: m.userId === currentUserId ? "#2563EB" : "#e5e7eb" }}
              >
                <Text
                  className="text-xs font-bold"
                  style={{ color: m.userId === currentUserId ? "#fff" : "#6b7280" }}
                >
                  {m.name.charAt(0).toUpperCase()}
                </Text>
              </View>
              <View>
                <Text className="text-base text-gray-900">
                  {m.name}{m.userId === currentUserId ? ` ${t('settings.youSuffix')}` : ""}
                </Text>
                <Text className="text-xs text-gray-400">{m.email}</Text>
              </View>
            </View>
            <Text className="text-xs text-gray-400 capitalize">{m.role}</Text>
          </View>
        ))}

        {/* Pending invitations */}
        {(data?.pendingInvitations ?? []).length > 0 && (
          <View className="mt-2">
            <Text className="text-xs text-gray-400 mb-1">{t('settings.pending')}</Text>
            {data!.pendingInvitations.map((inv: PendingInvitation) => (
              <View
                key={inv.id}
                className="flex-row items-center justify-between py-3 border-b border-gray-100"
              >
                <View className="flex-row items-center gap-3">
                  <View className="w-8 h-8 rounded-full items-center justify-center bg-gray-100">
                    <Ionicons name="mail-outline" size={16} color="#9ca3af" />
                  </View>
                  <Text className="text-base text-gray-500">{inv.email}</Text>
                </View>
                <Pressable onPress={() => handleRevoke(inv)} className="p-1 active:opacity-50">
                  <Ionicons name="close-circle-outline" size={20} color="#dc2626" />
                </Pressable>
              </View>
            ))}
          </View>
        )}

        {/* Invite button */}
        <Pressable
          onPress={() => setShowInviteModal(true)}
          className="mt-3 flex-row items-center justify-center gap-1.5 rounded-lg border border-blue-200 py-3 active:opacity-70"
        >
          <Ionicons name="person-add-outline" size={16} color="#2563EB" />
          <Text className="text-sm font-medium text-blue-600">{t('settings.invitePerson')}</Text>
        </Pressable>
      </View>

      <InviteCodeModal visible={showInviteModal} onClose={() => setShowInviteModal(false)} />
    </>
  );
}

// ── Main Screen ────────────────────────────────────────────────────────────────

export default function SettingsScreen() {
  const { user, households, activeHouseholdId, setActiveHousehold } = useAuthStore();
  const queryClient = useQueryClient();
  const router = useRouter();
  const insets = useSafeAreaInsets();
  const { t } = useTranslation();
  const { data: hhSettings } = useHouseholdSettings();
  const { mutate: updateSettings } = useUpdateHouseholdSettings();

  // Apply saved language preference when settings load
  useEffect(() => {
    if (hhSettings?.language && hhSettings.language !== "auto") {
      void i18n.changeLanguage(hhSettings.language);
    }
  }, [hhSettings?.language]);

  function handleLanguageChange() {
    const deviceLanguage = Localization.getLocales()[0]?.languageCode ?? "de";
    Alert.alert(t('settings.language'), undefined, [
      {
        text: t('settings.languageAuto'),
        onPress: () => {
          void i18n.changeLanguage(deviceLanguage);
          updateSettings({ language: "auto" });
        },
      },
      {
        text: t('settings.languageDe'),
        onPress: () => {
          void i18n.changeLanguage("de");
          updateSettings({ language: "de" });
        },
      },
      {
        text: t('settings.languageEn'),
        onPress: () => {
          void i18n.changeLanguage("en");
          updateSettings({ language: "en" });
        },
      },
      { text: t('common.cancel'), style: "cancel" },
    ]);
  }

  async function handleSwitch(household: { id: string; name: string }) {
    if (household.id === activeHouseholdId) return;
    setActiveHousehold(household.id);
    await queryClient.invalidateQueries();
    showToast(t('settings.switchedTo', { name: household.name }));
  }

  async function handleSignOut() {
    await signOut();
    useAuthStore.getState().clearAuth();
    router.replace("/(auth)/login");
  }

  return (
    <ScrollView
      className="flex-1 bg-gray-50"
      contentContainerStyle={{ padding: 16, paddingTop: insets.top + 8 }}
    >
      {/* Back + Title */}
      <View className="flex-row items-center mb-5">
        <Pressable onPress={() => router.push("/(app)/mehr")} className="mr-3 p-1">
          <Ionicons name="chevron-back" size={22} color="#374151" />
        </Pressable>
        <Text className="text-xl font-bold text-gray-900">{t('settings.title')}</Text>
      </View>

      {/* User Info */}
      <View className="mb-6 rounded-xl bg-white p-4">
        <Text className="text-xs font-medium uppercase text-gray-400 mb-2">{t('settings.account')}</Text>
        <Text className="text-base font-semibold text-gray-900">{user?.name}</Text>
        <Text className="text-sm text-gray-500">{user?.email}</Text>
      </View>

      {/* Household Switcher */}
      <View className="mb-6 rounded-xl bg-white p-4">
        <Text className="text-xs font-medium uppercase text-gray-400 mb-3">{t('settings.households')}</Text>
        {households.map((h) => (
          <Pressable
            key={h.id}
            onPress={() => handleSwitch(h)}
            className="flex-row items-center justify-between py-3 border-b border-gray-100 active:opacity-70 last:border-b-0"
          >
            <View>
              <Text className="text-base text-gray-900">{h.name}</Text>
              <Text className="text-xs text-gray-400 capitalize">{h.role}</Text>
            </View>
            {activeHouseholdId === h.id && (
              <Ionicons name="checkmark-circle" size={20} color="#2563EB" />
            )}
          </Pressable>
        ))}
        <Pressable
          onPress={() => router.push("/(auth)/onboarding")}
          className="mt-3 flex-row items-center justify-center gap-1.5 rounded-lg border border-blue-200 py-3 active:opacity-70"
        >
          <Ionicons name="add-circle-outline" size={16} color="#2563EB" />
          <Text className="text-sm font-medium text-blue-600">{t('onboarding.createHousehold')}</Text>
        </Pressable>
      </View>

      {/* Members + Invite */}
      <MembersSection />

      {/* Household Settings */}
      <View className="mb-6 rounded-xl bg-white p-4">
        <Text className="text-xs font-medium uppercase text-gray-400 mb-3">{t('tabs.household')}</Text>
        <Pressable
          onPress={() => router.push("/(app)/settings/household")}
          className="flex-row items-center justify-between py-3 active:opacity-70"
        >
          <View className="flex-row items-center gap-3">
            <Ionicons name="people-outline" size={20} color="#6b7280" />
            <Text className="text-base text-gray-900">{t('settings.householdPartner')}</Text>
          </View>
          <Ionicons name="chevron-forward" size={16} color="#9ca3af" />
        </Pressable>
      </View>

      {/* App Settings */}
      <View className="mb-6 rounded-xl bg-white p-4">
        <Text className="text-xs font-medium uppercase text-gray-400 mb-3">{t('settings.appSection')}</Text>
        <Pressable
          onPress={() => router.push("/(app)/settings/categories")}
          className="flex-row items-center justify-between py-3 border-b border-gray-100 active:opacity-70"
        >
          <View className="flex-row items-center gap-3">
            <Ionicons name="pricetags-outline" size={20} color="#6b7280" />
            <Text className="text-base text-gray-900">{t('settings.categories')}</Text>
          </View>
          <Ionicons name="chevron-forward" size={16} color="#9ca3af" />
        </Pressable>
        <Pressable
          onPress={() => router.push("/(app)/settings/fixed-costs")}
          className="flex-row items-center justify-between py-3 border-b border-gray-100 active:opacity-70"
        >
          <View className="flex-row items-center gap-3">
            <Ionicons name="repeat-outline" size={20} color="#6b7280" />
            <Text className="text-base text-gray-900">{t('settings.fixedCosts')}</Text>
          </View>
          <Ionicons name="chevron-forward" size={16} color="#9ca3af" />
        </Pressable>
        <Pressable
          onPress={() => router.push("/(app)/settings/transfer-line-items")}
          className="flex-row items-center justify-between py-3 border-b border-gray-100 active:opacity-70"
        >
          <View className="flex-row items-center gap-3">
            <Ionicons name="swap-horizontal-outline" size={20} color="#6b7280" />
            <Text className="text-base text-gray-900">{t('settings.transferItems')}</Text>
          </View>
          <Ionicons name="chevron-forward" size={16} color="#9ca3af" />
        </Pressable>
        <Pressable
          onPress={handleLanguageChange}
          className="flex-row items-center justify-between py-3 active:opacity-70"
        >
          <View className="flex-row items-center gap-3">
            <Ionicons name="language-outline" size={20} color="#6b7280" />
            <Text className="text-base text-gray-900">{t('settings.language')}</Text>
          </View>
          <View className="flex-row items-center gap-1">
            <Text className="text-sm text-gray-400">
              {(() => {
                switch (hhSettings?.language) {
                  case "de": return t('settings.languageDe');
                  case "en": return t('settings.languageEn');
                  default: return t('settings.languageAuto');
                }
              })()}
            </Text>
            <Ionicons name="chevron-forward" size={16} color="#9ca3af" />
          </View>
        </Pressable>
      </View>

      {/* Sign Out */}
      <Pressable
        onPress={handleSignOut}
        className="rounded-xl bg-red-50 p-4 flex-row items-center justify-center gap-2 active:opacity-70"
      >
        <Ionicons name="log-out-outline" size={18} color="#dc2626" />
        <Text className="text-base font-semibold text-red-600">{t('settings.logout')}</Text>
      </Pressable>
    </ScrollView>
  );
}