/**
 * 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, safeBack } 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: 'Min'      },
  { value: 10_000, label: 'Standard' },
  { value: 50_000, label: 'Priority' },
];

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} is not registered on this chain`); return; }
        address = addr;
      }
      // Block self-lookup — can't message yourself, and the on-chain
      // CONTACT_REQUEST tx would go through but serve no purpose.
      if (keyFile && address.toLowerCase() === keyFile.pub_key.toLowerCase()) {
        setError("That's you. You can't send a contact request to yourself.");
        return;
      }
      const identity = await getIdentity(address);
      const resolvedAddr = identity?.pub_key ?? address;
      if (keyFile && resolvedAddr.toLowerCase() === keyFile.pub_key.toLowerCase()) {
        setError("That's you. You can't send a contact request to yourself.");
        return;
      }
      setResolved({
        address:  resolvedAddr,
        nickname: identity?.nickname || undefined,
        x25519:   identity?.x25519_pub || undefined,
      });
    } catch (e: any) {
      setError(e?.message ?? 'Lookup failed');
    } finally {
      setSearching(false);
    }
  }

  async function sendRequest() {
    if (!resolved || !keyFile) return;
    if (resolved.address.toLowerCase() === keyFile.pub_key.toLowerCase()) {
      Alert.alert('Can\'t message yourself', "This is your own address.");
      return;
    }
    if (balance < fee + 1000) {
      Alert.alert('Insufficient balance', `Need ${formatAmount(fee + 1000)} (request fee + network).`);
      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(
        'Request sent',
        `A contact request has been sent to ${resolved.nickname ? '@' + resolved.nickname : shortAddr(resolved.address)}.`,
        [{ text: 'OK', onPress: () => safeBack() }],
      );
    } 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="Search"
        divider={false}
        left={<IconButton icon="chevron-back" size={36} onPress={() => safeBack()} />}
      />
      <ScrollView
        contentContainerStyle={{ padding: 14, paddingBottom: 120 }}
        keyboardShouldPersistTaps="handled"
        showsVerticalScrollIndicator={false}
      >
        <SearchBar
          value={query}
          onChangeText={setQuery}
          placeholder="@alice, hex pubkey or DC address"
          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 }}>Search</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 }}>
              Find someone to message
            </Text>
            <Text style={{ color: '#8b8b8b', fontSize: 13, textAlign: 'center', lineHeight: 19 }}>
              Enter an <Text style={{ color: '#ffffff', fontWeight: '600' }}>@username</Text> if
              the person registered one, or paste a full hex pubkey or <Text style={{ color: '#ffffff', fontWeight: '600' }}>DC…</Text> address.
            </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 ready' : 'Key not published yet'}
                    </Text>
                  </View>
                </View>
              </View>
            </View>

            {/* Intro */}
            <Text style={{ color: '#8b8b8b', fontSize: 12, marginTop: 18, marginBottom: 6 }}>
              Intro (optional, plaintext on-chain)
            </Text>
            <TextInput
              value={intro}
              onChangeText={setIntro}
              placeholder="Hey, it's Jordan from the conference"
              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 }}>
              Anti-spam fee (goes to the recipient)
            </Text>
            {/* Fee-tier pills.
                Layout (background, border, padding) lives on a static
                inner View — Pressable's dynamic style-function has been
                observed to drop backgroundColor between renders on
                some RN/Android versions, which is what made these
                chips look like three bare text labels on black
                instead of distinct pills. Press feedback via opacity
                on the Pressable itself, which is stable. */}
            <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,
                      opacity: pressed ? 0.7 : 1,
                    })}
                  >
                    <View
                      style={{
                        alignItems: 'center',
                        paddingVertical: 10,
                        borderRadius: 10,
                        backgroundColor: active ? '#ffffff' : '#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>
                    </View>
                  </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 }}>
                  Send request · {formatAmount(fee + 1000)}
                </Text>
              )}
            </Pressable>
          </>
        )}
      </ScrollView>
    </View>
  );
}