import { Stack, useLocalSearchParams, router } from 'expo-router';
import { useMemo, useState } from 'react';
import { ActivityIndicator, FlatList, Pressable, ScrollView, StyleSheet, Text, View } from 'react-native';
import { useQuery } from '@tanstack/react-query';
import { useTranslation } from 'react-i18next';
import { fetchRecipes } from '@/src/api/recipes.api';
import { EmptyState, RecipeCard } from '@/src/components/RecipeCard';
import { ErrorView } from '@/src/components/ErrorView';
import { Screen } from '@/src/components/Screen';
import { useAppearance } from '@/src/context/AppearanceContext';
import { categoryLabel, parseCategoryParam } from '@/src/utils/recipe';
import { nextSort, sortBy, sortIndicator, type SortDirection } from '@/src/utils/sort';

type RecipeSortColumn = 'name' | 'calories' | 'prepTime';

const RECIPE_SORT_COLUMNS: { id: RecipeSortColumn; labelKey: string }[] = [
  { id: 'name', labelKey: 'manage.recipeName' },
  { id: 'calories', labelKey: 'recipes.calories' },
  { id: 'prepTime', labelKey: 'manage.prepTimeMin' },
];

export default function CategoryScreen() {
  const { category: categoryParam } = useLocalSearchParams<{ category: string }>();
  const category = parseCategoryParam(categoryParam ?? '');
  const { t } = useTranslation();
  const { colors } = useAppearance();
  const [recipeSort, setRecipeSort] = useState<{ column: RecipeSortColumn; direction: SortDirection }>({
    column: 'name',
    direction: 'asc',
  });

  const recipesQuery = useQuery({
    queryKey: ['recipes', 'category', category],
    queryFn: () => fetchRecipes({ category: category! }),
    enabled: category != null,
  });

  const title = category != null ? categoryLabel(category, t) : t('categories.unknown');

  const sortedRecipes = useMemo(() => {
    const list = recipesQuery.data ?? [];
    const { column, direction } = recipeSort;
    return sortBy(list, direction, (recipe) => {
      switch (column) {
        case 'name':
          return recipe.name;
        case 'calories':
          return recipe.calories;
        case 'prepTime':
          return recipe.prepTimeMinutes;
      }
    });
  }, [recipesQuery.data, recipeSort]);

  if (category == null) {
    return (
      <Screen>
        <ErrorView message={t('errors.loadRecipesFailed')} />
      </Screen>
    );
  }

  return (
    <>
      <Stack.Screen options={{ title, headerShown: true }} />
      <Screen subtitle={t('common.recipeCount', { count: recipesQuery.data?.length ?? 0 })}>
        {(recipesQuery.data?.length ?? 0) > 0 ? (
          <ScrollView horizontal showsHorizontalScrollIndicator={false} contentContainerStyle={styles.sortRow}>
            {RECIPE_SORT_COLUMNS.map(({ id, labelKey }) => (
              <SortChip
                key={id}
                label={`${t(labelKey)}${sortIndicator(recipeSort, id)}`}
                active={recipeSort.column === id}
                onPress={() => setRecipeSort((current) => nextSort(current, id))}
              />
            ))}
          </ScrollView>
        ) : null}
        {recipesQuery.isLoading ? (
          <View style={styles.loading}>
            <ActivityIndicator size="large" color={colors.brand} />
          </View>
        ) : recipesQuery.isError ? (
          <ErrorView
            message={t('errors.loadRecipesFailed')}
            onRetry={() => recipesQuery.refetch()}
          />
        ) : (
          <FlatList
            data={sortedRecipes}
            keyExtractor={(item) => String(item.id)}
            contentContainerStyle={styles.list}
            ListEmptyComponent={
              <EmptyState
                title={t('recipes.emptyCategoryTitle', { category: title })}
                description={t('recipes.emptyCategoryDescription')}
              />
            }
            renderItem={({ item }) => (
              <RecipeCard
                recipe={item}
                onPress={() => router.push(`/(main)/recipe/${item.id}`)}
              />
            )}
          />
        )}
      </Screen>
    </>
  );
}

function SortChip({ label, active, onPress }: { label: string; active: boolean; onPress: () => void }) {
  const { colors } = useAppearance();
  return (
    <Pressable
      onPress={onPress}
      style={[
        styles.sortChip,
        {
          backgroundColor: active ? colors.brand : colors.surface,
          borderColor: active ? colors.brand : colors.border,
        },
      ]}
    >
      <Text style={{ color: active ? '#fff' : colors.text, fontWeight: '600', fontSize: 12 }}>{label}</Text>
    </Pressable>
  );
}

const styles = StyleSheet.create({
  sortRow: {
    gap: 8,
    paddingBottom: 8,
  },
  sortChip: {
    borderWidth: 1,
    borderRadius: 999,
    paddingHorizontal: 12,
    paddingVertical: 6,
  },
  list: {
    gap: 10,
    paddingBottom: 24,
    flexGrow: 1,
  },
  loading: {
    flex: 1,
    alignItems: 'center',
    justifyContent: 'center',
    paddingVertical: 40,
  },
});