import { View, Text, Pressable, ScrollView, RefreshControl } from "react-native";
import { useLocalSearchParams, Link } from "expo-router";
import { useState, useCallback } from "react";
import { Ionicons } from "@expo/vector-icons";
import { useTheme } from "../../../components/theme";
import { usePaginatedQuery, useQuery } from "convex/react";
import { api } from "../../../convex/_generated/api";
import { CategoryGrid } from "../../../components/category-grid";
import { AdCard } from "../../../components/ad-card";
import { Loading } from "../../../components/ui/loading";
import { CATEGORIES, CATEGORY_EMOJI, getCategoryName } from "../../../lib/constants";

export default function ExploreScreen() {
  const theme = useTheme();
  const { category } = useLocalSearchParams<{ category?: string }>();
  const [refreshing, setRefreshing] = useState(false);

  const categories = useQuery(api.categories.list);
  const categoryAdsResult = usePaginatedQuery(
    api.ads.getByCategoryPaginated,
    category ? { category } : "skip",
    { initialNumItems: 20 }
  );
  const allAdsResult = usePaginatedQuery(api.ads.listPaginated, {}, { initialNumItems: 20 });

  const onRefresh = useCallback(() => {
    setRefreshing(true);
    setTimeout(() => setRefreshing(false), 800);
  }, []);

  const displayCategories = categories ?? CATEGORIES;

  if (category) {
    const catName = getCategoryName(category);
    const catEmoji = CATEGORY_EMOJI[category] ?? "📋";

    return (
      <View style={{ flex: 1, backgroundColor: theme.colors.background }}>
        <View
          style={{
            backgroundColor: theme.colors.surface,
            paddingTop: 60,
            paddingBottom: theme.spacing.md,
            paddingHorizontal: theme.spacing.md,
            borderBottomWidth: 1,
            borderBottomColor: theme.colors.divider,
            ...theme.shadows.xs,
          }}
        >
          <View style={{ flexDirection: "row", alignItems: "center", gap: theme.spacing.md }}>
            <Link href="/(tabs)/(explore)" asChild>
              <Pressable
                accessible
                accessibilityLabel="Назад"
                accessibilityRole="link"
                style={{
                  width: 40,
                  height: 40,
                  borderRadius: 20,
                  backgroundColor: theme.colors.surfaceAlt,
                  alignItems: "center",
                  justifyContent: "center",
                }}
              >
                <Ionicons name="arrow-back" size={20} color={theme.colors.text} />
              </Pressable>
            </Link>
            <View
              style={{
                width: 44,
                height: 44,
                borderRadius: theme.radius.md,
                backgroundColor: theme.colors.primaryLight,
                alignItems: "center",
                justifyContent: "center",
              }}
            >
              <Text style={{ fontSize: 22 }}>{catEmoji}</Text>
            </View>
            <Text selectable style={{ ...theme.typography.h3, color: theme.colors.text }}>
              {catName}
            </Text>
          </View>
        </View>

        <ScrollView
          contentInsetAdjustmentBehavior="automatic"
          refreshControl={
            <RefreshControl refreshing={refreshing} onRefresh={onRefresh} tintColor={theme.colors.primary} />
          }
          contentContainerStyle={{ padding: theme.spacing.md, gap: theme.spacing.sm, paddingBottom: 100 }}
        >
          {categoryAdsResult.status === "LoadingFirstPage" ? (
            <Loading skeleton />
          ) : categoryAdsResult.results.length === 0 ? (
            <View style={{ alignItems: "center", paddingVertical: theme.spacing.xxl }}>
              <View
                style={{
                  width: 72,
                  height: 72,
                  borderRadius: 36,
                  backgroundColor: theme.colors.primaryLight,
                  alignItems: "center",
                  justifyContent: "center",
                  marginBottom: theme.spacing.md,
                  ...theme.shadows.xs,
                }}
              >
                <Ionicons name="folder-open" size={30} color={theme.colors.primary} />
              </View>
              <Text style={{ ...theme.typography.bodyBold, color: theme.colors.text, marginBottom: theme.spacing.xs }}>
                Нема огласи
              </Text>
              <Text style={{ ...theme.typography.caption, color: theme.colors.textSecondary, textAlign: "center" }}>
                Нема огласи во оваа категорија
              </Text>
            </View>
          ) : (
            categoryAdsResult.results.map((ad) => (
              <AdCard key={ad._id} ad={ad} />
            ))
          )}

          {categoryAdsResult.status === "CanLoadMore" && (
            <Pressable
              accessible
              accessibilityLabel="Вчитај повеќе огласи"
              accessibilityRole="button"
              onPress={() => categoryAdsResult.loadMore(20)}
              style={{
                backgroundColor: theme.colors.surface,
                borderRadius: theme.radius.lg,
                paddingVertical: 14,
                alignItems: "center",
                borderWidth: 1,
                borderColor: theme.colors.border,
                marginTop: theme.spacing.sm,
                ...theme.shadows.xs,
              }}
            >
              <Text style={{ color: theme.colors.primary, fontWeight: "600", fontSize: 14 }}>
                Вчитај повеќе
              </Text>
            </Pressable>
          )}
        </ScrollView>
      </View>
    );
  }

  return (
    <View style={{ flex: 1, backgroundColor: theme.colors.background }}>
      <View style={{ paddingHorizontal: theme.spacing.md, paddingTop: 60, paddingBottom: theme.spacing.md, backgroundColor: theme.colors.surface, ...theme.shadows.xs }}>
        <Text style={{ ...theme.typography.h2, color: theme.colors.text }}>
          Категории
        </Text>
        <Text style={{ ...theme.typography.caption, color: theme.colors.textSecondary, marginTop: 4 }}>
          Изберете категорија за да пребарувате
        </Text>
      </View>

      <ScrollView
        contentInsetAdjustmentBehavior="automatic"
        refreshControl={
          <RefreshControl refreshing={refreshing} onRefresh={onRefresh} tintColor={theme.colors.primary} />
        }
        contentContainerStyle={{ padding: theme.spacing.md, gap: theme.spacing.md, paddingBottom: 100 }}
      >
        <CategoryGrid categories={displayCategories} />

        <View style={{ marginTop: theme.spacing.lg }}>
          <View style={{ flexDirection: "row", alignItems: "center", gap: theme.spacing.sm, marginBottom: theme.spacing.md }}>
            <Text style={{ ...theme.typography.h4, color: theme.colors.text }}>
              Сите огласи
            </Text>
            <View style={{ backgroundColor: theme.colors.surfaceAlt, paddingHorizontal: 10, paddingVertical: 3, borderRadius: theme.radius.full }}>
              <Text style={{ ...theme.typography.label, color: theme.colors.textSecondary }}>
                {allAdsResult.results.length}+
              </Text>
            </View>
          </View>

          {allAdsResult.status === "LoadingFirstPage" ? (
            <Loading skeleton />
          ) : allAdsResult.results.length === 0 ? (
            <View style={{ alignItems: "center", paddingVertical: theme.spacing.xxl }}>
              <View
                style={{
                  width: 72,
                  height: 72,
                  borderRadius: 36,
                  backgroundColor: theme.colors.surfaceAlt,
                  alignItems: "center",
                  justifyContent: "center",
                  marginBottom: theme.spacing.md,
                  ...theme.shadows.xs,
                }}
              >
                <Ionicons name="cube" size={30} color={theme.colors.textTertiary} />
              </View>
              <Text style={{ ...theme.typography.caption, color: theme.colors.textSecondary }}>
                Нема огласи
              </Text>
            </View>
          ) : (
            allAdsResult.results.map((ad) => (
              <AdCard key={ad._id} ad={ad} />
            ))
          )}

          {allAdsResult.status === "CanLoadMore" && (
            <Pressable
              accessible
              accessibilityLabel="Вчитај повеќе огласи"
              accessibilityRole="button"
              onPress={() => allAdsResult.loadMore(20)}
              style={{
                backgroundColor: theme.colors.surface,
                borderRadius: theme.radius.lg,
                paddingVertical: 14,
                alignItems: "center",
                borderWidth: 1,
                borderColor: theme.colors.border,
                marginTop: theme.spacing.sm,
                ...theme.shadows.xs,
              }}
            >
              <Text style={{ color: theme.colors.primary, fontWeight: "600", fontSize: 14 }}>
                Вчитај повеќе
              </Text>
            </Pressable>
          )}
        </View>
      </ScrollView>
    </View>
  );
}