import React, { useMemo, useState } from 'react';
import { FlatList, ScrollView, StyleSheet, Text, View } from 'react-native';
import { useRouter } from 'expo-router';
import { useQuery } from '@tanstack/react-query';
import { api, DocCategory } from '@/api';
import { useT } from '@/i18n';
import { AppBar } from '@/components/AppBar';
import { Chip, EmptyState, Loading, TextField } from '@/components/ui';
import { DocumentRow } from '@/components/domain';
import { DocWithProperty, fetchAllDocuments } from '@/lib/allDocuments';
import { colors, fontSize, spacing } from '@/theme';

export default function SearchScreen() {
  const router = useRouter();
  const t = useT();
  const [query, setQuery] = useState('');
  const [category, setCategory] = useState<string>('all');

  const docsQuery = useQuery({ queryKey: ['all-documents'], queryFn: fetchAllDocuments });
  const catsQuery = useQuery({ queryKey: ['categories'], queryFn: () => api.reference.categories() });

  const categories: DocCategory[] = catsQuery.data ?? [];
  const catName = (slug: string) => categories.find((c) => c.slug === slug)?.name ?? slug;

  const results = useMemo(() => {
    const docs: DocWithProperty[] = docsQuery.data ?? [];
    const q = query.trim().toLowerCase();
    return docs.filter((d) => {
      const matchesCat = category === 'all' || d.category === category;
      const matchesQuery =
        !q || d.name.toLowerCase().includes(q) || catName(d.category).toLowerCase().includes(q);
      return matchesCat && matchesQuery;
    });
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [docsQuery.data, query, category, categories]);

  return (
    <View style={{ flex: 1, backgroundColor: colors.bgApp }}>
      <AppBar title={t('tabs.search')} large />

      <View style={styles.controls}>
        <TextField
          icon="search"
          value={query}
          onChangeText={setQuery}
          placeholder={t('properties.searchPlaceholder')}
          autoCapitalize="none"
          autoFocus
        />
        <ScrollView
          horizontal
          showsHorizontalScrollIndicator={false}
          contentContainerStyle={styles.chips}
        >
          <Chip label={t('common.all')} active={category === 'all'} onPress={() => setCategory('all')} />
          {categories.map((c) => (
            <Chip
              key={c.slug}
              label={c.name}
              active={category === c.slug}
              onPress={() => setCategory(c.slug)}
            />
          ))}
        </ScrollView>
      </View>

      {docsQuery.isLoading ? (
        <Loading />
      ) : (
        <FlatList
          data={results}
          keyExtractor={(d) => String(d.id)}
          contentContainerStyle={styles.list}
          ListHeaderComponent={
            <Text style={styles.count}>
              {t('properties.docCount', { count: results.length })}
            </Text>
          }
          renderItem={({ item }) => (
            <View style={{ marginBottom: spacing[3] }}>
              <DocumentRow
                document={item}
                subtitle={`${item.propertyName} · ${catName(item.category)}`}
                onPress={() => router.push(`/document/${item.id}?propertyId=${item.propertyId}`)}
              />
            </View>
          )}
          ListEmptyComponent={
            <EmptyState
              icon="search-outline"
              title={t('documents.emptyTitle')}
              subtitle={t('documents.emptySubtitle')}
            />
          }
        />
      )}
    </View>
  );
}

const styles = StyleSheet.create({
  controls: { paddingHorizontal: spacing[4], gap: spacing[3], paddingBottom: spacing[2] },
  chips: { gap: 8, paddingVertical: spacing[1], paddingRight: spacing[4] },
  list: { padding: spacing[4], paddingTop: spacing[2], paddingBottom: spacing[9] },
  count: { fontSize: fontSize.sm, color: colors.slate500, marginBottom: spacing[3], fontWeight: '600' },
});