/**
 * Add new contact — dark minimalist, inspired by the reference.
 *
 * Flow:
 *   1. Пользователь вводит @username или hex pubkey / DC-address.
 *   2. Жмёт Search → resolveUsername → getIdentity.
 *   3. Показываем preview (avatar + имя + address + наличие x25519).
 *   4. Выбирает fee (chip-selector) + вводит intro.
 *   5. Submit → CONTACT_REQUEST tx.
 */
import React, { useState } from 'react';
import {
  View, Text, ScrollView, Alert, Pressable, TextInput, ActivityIndicator,
} from 'react-native';
import { router } from 'expo-router';
import { Ionicons } from '@expo/vector-icons';
import { useSafeAreaInsets } from 'react-native-safe-area-context';
import { useStore } from '@/lib/store';
import { getIdentity, buildContactRequestTx, submitTx, resolveUsername, humanizeTxError } from '@/lib/api';
import { shortAddr } from '@/lib/crypto';
import { formatAmount } from '@/lib/utils';

import { Avatar } from '@/components/Avatar';
import { Header } from '@/components/Header';
import { IconButton } from '@/components/IconButton';
import { SearchBar } from '@/components/SearchBar';

const MIN_CONTACT_FEE = 5000;
const FEE_TIERS = [
  { value: 5_000,  label: 'Базовая'    },
  { value: 10_000, label: 'Стандарт'   },
  { value: 50_000, label: 'Приоритет'  },
];

interface Resolved {
  address:   string;
  nickname?: string;
  x25519?:   string;
}

export default function NewContactScreen() {
  const insets   = useSafeAreaInsets();
  const keyFile  = useStore(s => s.keyFile);
  const settings = useStore(s => s.settings);
  const balance  = useStore(s => s.balance);

  const [query,     setQuery]     = useState('');
  const [intro,     setIntro]     = useState('');
  const [fee,       setFee]       = useState(MIN_CONTACT_FEE);
  const [resolved,  setResolved]  = useState<Resolved | null>(null);
  const [searching, setSearching] = useState(false);
  const [sending,   setSending]   = useState(false);
  const [error,     setError]     = useState<string | null>(null);

  async function search() {
    const q = query.trim();
    if (!q) return;
    setSearching(true); setResolved(null); setError(null);
    try {
      let address = q;
      if (q.startsWith('@') || (!q.match(/^[0-9a-f]{64}$/i) && !q.startsWith('DC'))) {
        const name = q.replace('@', '');
        const addr = await resolveUsername(settings.contractId, name);
        if (!addr) { setError(`@${name} не зарегистрирован в этой сети`); return; }
        address = addr;
      }
      const identity = await getIdentity(address);
      setResolved({
        address:  identity?.pub_key ?? address,
        nickname: identity?.nickname || undefined,
        x25519:   identity?.x25519_pub || undefined,
      });
    } catch (e: any) {
      setError(e?.message ?? 'Не удалось найти пользователя');
    } finally {
      setSearching(false);
    }
  }

  async function sendRequest() {
    if (!resolved || !keyFile) return;
    if (balance < fee + 1000) {
      Alert.alert('Недостаточно средств', `Нужно ${formatAmount(fee + 1000)} (плата + сетевая комиссия).`);
      return;
    }
    setSending(true); setError(null);
    try {
      const tx = buildContactRequestTx({
        from:       keyFile.pub_key,
        to:         resolved.address,
        contactFee: fee,
        intro:      intro.trim() || undefined,
        privKey:    keyFile.priv_key,
      });
      await submitTx(tx);
      Alert.alert(
        'Запрос отправлен',
        `Запрос на общение отправлен ${resolved.nickname ? '@' + resolved.nickname : shortAddr(resolved.address)}.`,
        [{ text: 'OK', onPress: () => router.back() }],
      );
    } catch (e: any) {
      setError(humanizeTxError(e));
    } finally {
      setSending(false);
    }
  }

  const displayName = resolved
    ? (resolved.nickname ? `@${resolved.nickname}` : shortAddr(resolved.address))
    : '';

  return (
    <View style={{ flex: 1, backgroundColor: '#000000', paddingTop: insets.top }}>
      <Header
        title="Поиск"
        divider={false}
        left={<IconButton icon="chevron-back" size={36} onPress={() => router.back()} />}
      />
      <ScrollView
        contentContainerStyle={{ padding: 14, paddingBottom: 120 }}
        keyboardShouldPersistTaps="handled"
        showsVerticalScrollIndicator={false}
      >
        <SearchBar
          value={query}
          onChangeText={setQuery}
          placeholder="@alice, hex pubkey или DC-адрес"
          onSubmitEditing={search}
          autoFocus
          onClear={() => { setResolved(null); setError(null); }}
        />

        {query.trim().length > 0 && (
          <Pressable
            onPress={search}
            disabled={searching}
            style={({ pressed }) => ({
              flexDirection: 'row', alignItems: 'center', justifyContent: 'center',
              paddingVertical: 11, borderRadius: 999, marginTop: 12,
              backgroundColor: searching ? '#1a1a1a' : pressed ? '#1a8cd8' : '#1d9bf0',
            })}
          >
            {searching ? (
              <ActivityIndicator color="#ffffff" size="small" />
            ) : (
              <Text style={{ color: '#ffffff', fontWeight: '700', fontSize: 14 }}>Найти</Text>
            )}
          </Pressable>
        )}

        {/* Empty-state hint — показываем когда ничего не введено и нет результата */}
        {query.trim().length === 0 && !resolved && (
          <View style={{ marginTop: 28, alignItems: 'center', paddingHorizontal: 16 }}>
            <View
              style={{
                width: 56, height: 56, borderRadius: 16,
                backgroundColor: '#0a0a0a',
                borderWidth: 1, borderColor: '#1f1f1f',
                alignItems: 'center', justifyContent: 'center',
                marginBottom: 12,
              }}
            >
              <Ionicons name="person-add-outline" size={24} color="#6a6a6a" />
            </View>
            <Text style={{ color: '#ffffff', fontSize: 15, fontWeight: '700', marginBottom: 6 }}>
              Найдите собеседника
            </Text>
            <Text style={{ color: '#8b8b8b', fontSize: 13, textAlign: 'center', lineHeight: 19 }}>
              Введите <Text style={{ color: '#ffffff', fontWeight: '600' }}>@username</Text>,
              если человек зарегистрировал ник, либо полный hex pubkey или <Text style={{ color: '#ffffff', fontWeight: '600' }}>DC…</Text> адрес.
            </Text>
          </View>
        )}

        {error && (
          <View style={{
            marginTop: 14,
            padding: 12,
            borderRadius: 10,
            backgroundColor: 'rgba(244,33,46,0.08)',
            borderWidth: 1, borderColor: 'rgba(244,33,46,0.25)',
          }}>
            <Text style={{ color: '#f4212e', fontSize: 13 }}>{error}</Text>
          </View>
        )}

        {/* Resolved profile card */}
        {resolved && (
          <>
            <View style={{
              marginTop: 18,
              padding: 14,
              borderRadius: 14,
              backgroundColor: '#0a0a0a',
              borderWidth: 1, borderColor: '#1f1f1f',
            }}>
              <View style={{ flexDirection: 'row', alignItems: 'center', gap: 12 }}>
                <Avatar
                  name={displayName}
                  address={resolved.address}
                  size={52}
                  dotColor={resolved.x25519 ? '#3ba55d' : '#f0b35a'}
                />
                <View style={{ flex: 1, minWidth: 0 }}>
                  <Text style={{ color: '#ffffff', fontWeight: '700', fontSize: 16 }}>
                    {displayName}
                  </Text>
                  <Text style={{ color: '#8b8b8b', fontSize: 11, fontFamily: 'monospace', marginTop: 2 }} numberOfLines={1}>
                    {shortAddr(resolved.address, 10)}
                  </Text>
                  <View style={{ flexDirection: 'row', alignItems: 'center', marginTop: 5, gap: 4 }}>
                    <Ionicons
                      name={resolved.x25519 ? 'lock-closed' : 'time-outline'}
                      size={11}
                      color={resolved.x25519 ? '#3ba55d' : '#f0b35a'}
                    />
                    <Text style={{
                      color: resolved.x25519 ? '#3ba55d' : '#f0b35a',
                      fontSize: 11, fontWeight: '500',
                    }}>
                      {resolved.x25519 ? 'E2E готов' : 'Ключ ещё не опубликован'}
                    </Text>
                  </View>
                </View>
              </View>
            </View>

            {/* Intro */}
            <Text style={{ color: '#8b8b8b', fontSize: 12, marginTop: 18, marginBottom: 6 }}>
              Сообщение (опционально, видно в открытом виде на chain)
            </Text>
            <TextInput
              value={intro}
              onChangeText={setIntro}
              placeholder="Привет! Это Влад со встречи в среду"
              placeholderTextColor="#5a5a5a"
              multiline
              maxLength={140}
              style={{
                color: '#ffffff', fontSize: 14,
                backgroundColor: '#0a0a0a', borderRadius: 10,
                paddingHorizontal: 12, paddingVertical: 10,
                borderWidth: 1, borderColor: '#1f1f1f',
                minHeight: 80, textAlignVertical: 'top',
              }}
            />
            <Text style={{ color: '#5a5a5a', fontSize: 11, textAlign: 'right', marginTop: 4 }}>
              {intro.length}/140
            </Text>

            {/* Fee tier */}
            <Text style={{ color: '#8b8b8b', fontSize: 12, marginTop: 14, marginBottom: 6 }}>
              Плата за запрос (уходит получателю, anti-spam)
            </Text>
            <View style={{ flexDirection: 'row', gap: 8 }}>
              {FEE_TIERS.map(t => {
                const active = fee === t.value;
                return (
                  <Pressable
                    key={t.value}
                    onPress={() => setFee(t.value)}
                    style={({ pressed }) => ({
                      flex: 1,
                      alignItems: 'center',
                      paddingVertical: 10,
                      borderRadius: 10,
                      backgroundColor: active ? '#ffffff' : pressed ? '#1a1a1a' : '#111111',
                      borderWidth: 1, borderColor: active ? '#ffffff' : '#1f1f1f',
                    })}
                  >
                    <Text style={{
                      color: active ? '#000' : '#ffffff',
                      fontWeight: '700', fontSize: 13,
                    }}>
                      {t.label}
                    </Text>
                    <Text style={{
                      color: active ? '#333' : '#8b8b8b',
                      fontSize: 11, marginTop: 2,
                    }}>
                      {formatAmount(t.value)}
                    </Text>
                  </Pressable>
                );
              })}
            </View>

            {/* Submit */}
            <Pressable
              onPress={sendRequest}
              disabled={sending}
              style={({ pressed }) => ({
                flexDirection: 'row', alignItems: 'center', justifyContent: 'center',
                paddingVertical: 13, borderRadius: 999, marginTop: 20,
                backgroundColor: sending ? '#1a1a1a' : pressed ? '#1a8cd8' : '#1d9bf0',
              })}
            >
              {sending ? (
                <ActivityIndicator color="#ffffff" size="small" />
              ) : (
                <Text style={{ color: '#ffffff', fontWeight: '700', fontSize: 14 }}>
                  Отправить запрос · {formatAmount(fee + 1000)}
                </Text>
              )}
            </Pressable>
          </>
        )}
      </ScrollView>
    </View>
  );
}