import React, { useState, useEffect } from "react";
import {
  View,
  ScrollView,
  Pressable,
  ActivityIndicator,
  RefreshControl,
} from "react-native";
import { Text } from "@/components/ui/text";
import { useSirouRouter } from "@sirou/react-native";
import { AppRoutes } from "@/lib/routes";
import { api, newsApi } from "@/lib/api";
import { EmptyState } from "@/components/EmptyState";
import { ScreenWrapper } from "@/components/ScreenWrapper";
import { StandardHeader } from "@/components/StandardHeader";

interface NewsItem {
  id: string;
  title: string;
  content: string;
  category: "ANNOUNCEMENT" | "UPDATE" | "MAINTENANCE" | "NEWS";
  priority: "LOW" | "MEDIUM" | "HIGH";
  publishedAt: string;
  viewCount: number;
}

function getCategoryColor(category: string) {
  switch (category) {
    case "ANNOUNCEMENT":
      return "bg-amber-500";
    case "UPDATE":
      return "bg-blue-500";
    case "MAINTENANCE":
      return "bg-red-500";
    default:
      return "bg-emerald-500";
  }
}

function getCategoryLabel(category: string) {
  switch (category) {
    case "ANNOUNCEMENT":
      return "ANNOUNCEMENT";
    case "UPDATE":
      return "UPDATE";
    case "MAINTENANCE":
      return "MAINTENANCE";
    default:
      return "NEWS";
  }
}

export default function NewsListScreen() {
  const nav = useSirouRouter<AppRoutes>();

  const getNewsApi = () => {
    if (newsApi) return newsApi;
    return api.news;
  };

  const [allNews, setAllNews] = useState<NewsItem[]>([]);
  const [loading, setLoading] = useState(true);
  const [page, setPage] = useState(1);
  const [hasMore, setHasMore] = useState(true);
  const [loadingMore, setLoadingMore] = useState(false);
  const [refreshing, setRefreshing] = useState(false);

  const fetchNews = async (pageNum: number, isRefresh = false) => {
    try {
      if (!isRefresh) {
        pageNum === 1 ? setLoading(true) : setLoadingMore(true);
      }
      const service = getNewsApi();
      if (!service) throw new Error("News service unavailable");
      const response = await service.getAll({
        query: { page: pageNum, limit: 10, isPublished: true },
      });
      const newData = response.data || [];
      if (isRefresh) {
        setAllNews(newData);
      } else {
        setAllNews((prev) => (pageNum === 1 ? newData : [...prev, ...newData]));
      }
      setHasMore(response?.meta?.hasNextPage ?? false);
      setPage(pageNum);
    } catch (err) {
      console.error("[News] Fetch error:", err);
    } finally {
      setLoading(false);
      setLoadingMore(false);
      setRefreshing(false);
    }
  };

  useEffect(() => {
    fetchNews(1);
  }, []);

  const onRefresh = () => {
    setRefreshing(true);
    fetchNews(1, true);
  };

  const loadMore = () => {
    if (hasMore && !loadingMore && !loading) {
      fetchNews(page + 1);
    }
  };

  if (loading && allNews.length === 0) {
    return (
      <ScreenWrapper className="bg-background">
        <StandardHeader title="News & Updates" showBack />
        <View className="flex-1 items-center justify-center">
          <ActivityIndicator size="large" color="#E46212" />
        </View>
      </ScreenWrapper>
    );
  }

  return (
    <ScreenWrapper className="bg-background">
      <StandardHeader title="News & Updates" showBack />
      <ScrollView
        showsVerticalScrollIndicator={false}
        refreshControl={
          <RefreshControl
            refreshing={refreshing}
            onRefresh={onRefresh}
            tintColor="#E46212"
          />
        }
        contentContainerStyle={{ paddingBottom: 60 }}
        onScroll={({ nativeEvent }) => {
          const isCloseToBottom =
            nativeEvent.layoutMeasurement.height +
              nativeEvent.contentOffset.y >=
            nativeEvent.contentSize.height - 20;
          if (isCloseToBottom) loadMore();
        }}
        scrollEventThrottle={400}
      >
        <View className="px-[16px] pt-6">
          <Text className="text-[9px] font-sans-black uppercase tracking-widest text-muted-foreground mb-3">
            Latest News
          </Text>

          {allNews.length > 0 ? (
            <View className="gap-2">
              {allNews.map((item) => (
                <Pressable
                  key={item.id}
                  onPress={() => nav.go("news/[id]", { id: item.id })}
                >
                  <View className="rounded-xl border border-border bg-card overflow-hidden">
                    <View className="p-4">
                      <View className="flex-row items-center gap-2 mb-1.5">
                        <View
                          className={`w-1.5 h-1.5 rounded-full ${getCategoryColor(item.category)}`}
                        />
                        <Text className="text-[9px] font-sans-black uppercase tracking-widest text-muted-foreground">
                          {getCategoryLabel(item.category)}
                        </Text>
                        <Text className="text-[9px] font-sans-medium text-muted-foreground ml-auto">
                          {new Date(item.publishedAt).toLocaleDateString()}
                        </Text>
                      </View>
                      <Text
                        className="text-foreground font-sans-bold text-sm"
                        numberOfLines={1}
                      >
                        {item.title}
                      </Text>
                      <Text
                        variant="muted"
                        className="text-[11px] leading-relaxed mt-1"
                        numberOfLines={2}
                      >
                        {item.content}
                      </Text>
                    </View>
                  </View>
                </Pressable>
              ))}
              {hasMore && (
                <Pressable
                  onPress={loadMore}
                  disabled={loadingMore}
                  className="py-4 items-center"
                >
                  {loadingMore ? (
                    <ActivityIndicator color="#E46212" size="small" />
                  ) : (
                    <Text className="text-primary font-sans-bold text-[10px] uppercase tracking-widest">
                      Load More
                    </Text>
                  )}
                </Pressable>
              )}
            </View>
          ) : (
            <EmptyState title="No news yet" centered />
          )}
        </View>
      </ScrollView>
    </ScreenWrapper>
  );
}