import { Ionicons } from "@expo/vector-icons";
import { useState } from "react";
import {
  ActivityIndicator,
  Alert,
  Modal,
  Pressable,
  Text,
  TextInput,
  View,
  FlatList,
} from "react-native";
import { useSafeAreaInsets } from "react-native-safe-area-context";
import { useRouter } from "expo-router";
import { useTranslation } from "react-i18next";
import {
  useTransferLineItems,
  useCreateTransferLineItem,
  useDeleteTransferLineItem,
  type TransferLineItem,
} from "@/src/hooks/useFixedCosts";
import { ModalHeader } from "@/src/components/ui/ModalHeader";
import { Numpad } from "@/src/components/ui/Numpad";
import { formatEur } from "@/src/utils/format";
import { handleNumpadKey, parseAmountStr } from "@/src/utils/numpad";

function AddModal({ onClose }: { onClose: () => void }) {
  const [label, setLabel] = useState("");
  const [amountStr, setAmountStr] = useState("0");
  const { mutate: create, isPending } = useCreateTransferLineItem();
  const { t } = useTranslation();

  function handleNumpad(key: string) {
    setAmountStr((prev) => handleNumpadKey(prev, key));
  }

  function handleSave() {
    const amount = parseAmountStr(amountStr);
    if (!label.trim() || !amount || amount <= 0) return;
    create({ label: label.trim(), amount }, { onSuccess: onClose });
  }

  const canSave = label.trim().length > 0 && parseAmountStr(amountStr) > 0;

  return (
    <Modal visible animationType="slide" presentationStyle="pageSheet" onRequestClose={onClose}>
      <View className="flex-1 bg-white">
        <ModalHeader
          title={t('transferItems.addTitle')}
          onClose={onClose}
          closeLabel={t('common.cancel')}
          onSave={handleSave}
          saveLabel={t('common.save')}
          saveDisabled={!canSave}
          saveLoading={isPending}
        />

        <View className="items-center py-6">
          <Text className="text-5xl font-bold text-gray-900">€ {amountStr}</Text>
          <Text className="text-sm text-gray-400 mt-1">{t('transferItems.monthlyFixedAmount')}</Text>
        </View>

        <View className="px-4 mb-4">
          <Text className="text-sm font-medium text-gray-700 mb-1">{t('transferItems.labelRequired')}</Text>
          <TextInput
            className="bg-gray-50 border border-gray-200 rounded-xl px-4 py-3 text-base text-gray-900"
            placeholder={t('transferItems.labelPlaceholder')}
            value={label}
            onChangeText={setLabel}
          />
        </View>

        <Numpad onKeyPress={handleNumpad} />
      </View>
    </Modal>
  );
}

export default function TransferLineItemsScreen() {
  const insets = useSafeAreaInsets();
  const router = useRouter();
  const { t } = useTranslation();
  const { data: items = [], isLoading } = useTransferLineItems();
  const { mutate: deleteItem } = useDeleteTransferLineItem();
  const [showAdd, setShowAdd] = useState(false);

  const total = items.reduce((sum, i) => sum + i.amount, 0);

  function handleDelete(item: TransferLineItem) {
    Alert.alert(
      t('transferItems.removeTitle'),
      t('transferItems.removeMessage', { label: item.label }),
      [
        { text: t('common.cancel'), style: "cancel" },
        { text: t('transferItems.remove'), style: "destructive", onPress: () => deleteItem(item.id) },
      ],
    );
  }

  return (
    <View className="flex-1 bg-gray-50">
      <View className="bg-white border-b border-gray-100" style={{ paddingTop: insets.top }}>
        <View className="flex-row items-center px-4 py-3">
          <Pressable onPress={() => router.push("/(app)/settings")} className="mr-3 p-1">
            <Ionicons name="chevron-back" size={22} color="#374151" />
          </Pressable>
          <Text className="text-base font-semibold text-gray-900 flex-1">{t('transferItems.title')}</Text>
          <Pressable
            onPress={() => setShowAdd(true)}
            className="flex-row items-center gap-1 px-3 py-1.5 rounded-full"
            style={{ backgroundColor: "#dbeafe" }}
          >
            <Ionicons name="add" size={14} color="#2563EB" />
            <Text className="text-xs font-semibold text-blue-600">{t('transferItems.new')}</Text>
          </Pressable>
        </View>
      </View>

      <Text className="text-xs text-gray-400 px-4 py-3">
        {t('transferItems.hint')}
      </Text>

      {isLoading ? (
        <View className="flex-1 items-center justify-center">
          <ActivityIndicator size="large" color="#2563EB" />
        </View>
      ) : (
        <FlatList
          data={items}
          keyExtractor={(item) => item.id}
          renderItem={({ item }) => (
            <View className="flex-row items-center px-4 py-3 bg-white border-b border-gray-50">
              <View className="flex-1">
                <Text className="text-sm font-medium text-gray-900">{item.label}</Text>
                <Text className="text-xs text-gray-400 mt-0.5">{t('common.monthly')}</Text>
              </View>
              <Text className="text-sm font-semibold text-gray-800 mr-3">{formatEur(item.amount, false)}</Text>
              <Pressable onPress={() => handleDelete(item)} hitSlop={8} className="p-1">
                <Ionicons name="trash-outline" size={16} color="#d1d5db" />
              </Pressable>
            </View>
          )}
          ListEmptyComponent={
            <View className="px-4 py-8 items-center">
              <Text className="text-sm text-gray-400 text-center">
                {t('transferItems.empty')}
              </Text>
            </View>
          }
          ListFooterComponent={
            items.length > 0 ? (
              <View className="flex-row items-center justify-between px-4 py-3 bg-white mt-3">
                <Text className="text-sm font-semibold text-gray-700">{t('transferItems.totalMonthly')}</Text>
                <Text className="text-sm font-bold text-blue-600">{formatEur(total, false)}</Text>
              </View>
            ) : null
          }
          contentContainerStyle={{ paddingBottom: insets.bottom + 24 }}
        />
      )}

      {showAdd && <AddModal onClose={() => setShowAdd(false)} />}
    </View>
  );
}