import React, { useState, useEffect, useCallback } from "react";
import {
  View,
  Pressable,
  ActivityIndicator,
  FlatList,
  ListRenderItem,
} from "react-native";
import { Text } from "@/components/ui/text";
import { Card } from "@/components/ui/card";
import { useSirouRouter } from "@sirou/react-native";
import { AppRoutes } from "@/lib/routes";
import { Plus, Send, FileText, Clock } from "@/lib/icons";
import { ScreenWrapper } from "@/components/ScreenWrapper";
import { StandardHeader } from "@/components/StandardHeader";
import { Button } from "@/components/ui/button";
import { api } from "@/lib/api";
import { useAuthStore } from "@/lib/auth-store";

interface ProformaItem {
  id: string;
  proformaNumber: string;
  customerName: string;
  amount: any;
  currency: string;
  issueDate: string;
  dueDate: string;
  description: string;
}

export default function ProformaScreen() {
  const nav = useSirouRouter<AppRoutes>();
  const [proformas, setProformas] = useState<ProformaItem[]>([]);
  const [loading, setLoading] = useState(true);
  const [refreshing, setRefreshing] = useState(false);
  const [page, setPage] = useState(1);
  const [hasMore, setHasMore] = useState(true);
  const [loadingMore, setLoadingMore] = useState(false);

  const fetchProformas = useCallback(
    async (pageNum: number, isRefresh = false) => {
      const { isAuthenticated } = useAuthStore.getState();
      if (!isAuthenticated) return;

      try {
        if (!isRefresh) {
          pageNum === 1 ? setLoading(true) : setLoadingMore(true);
        }

        const response = await api.proforma.getAll({
          query: { page: pageNum, limit: 10 },
        });

        const newData = response.data;
        if (isRefresh) {
          setProformas(newData);
        } else {
          setProformas((prev) =>
            pageNum === 1 ? newData : [...prev, ...newData],
          );
        }

        setHasMore(response.meta.hasNextPage);
        setPage(pageNum);
      } catch (err: any) {
        console.error("[Proforma] Fetch error:", err);
      } finally {
        setLoading(false);
        setRefreshing(false);
        setLoadingMore(false);
      }
    },
    [],
  );

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

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

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

  const renderProformaItem: ListRenderItem<ProformaItem> = ({ item }) => {
    const amountVal =
      typeof item.amount === "object" ? item.amount.value : item.amount;
    const dateStr = new Date(item.issueDate).toLocaleDateString();

    return (
      <Pressable
        key={item.id}
        onPress={() => nav.go("proforma/[id]", { id: item.id })}
        className="mb-3"
      >
        <Card className="rounded-[10px] bg-card overflow-hidden">
          <View className="p-4">
            <View className="flex-row justify-between items-start mb-3">
              <View className="bg-primary/10 p-2.5 rounded-[12px] border border-primary/5">
                <FileText color="#ea580c" size={20} strokeWidth={2.5} />
              </View>
              <View className="items-end">
                <Text variant="p" className="text-foreground font-bold text-lg">
                  {item.currency || "$"}
                  {amountVal?.toLocaleString()}
                </Text>
                <Text
                  variant="muted"
                  className="text-[10px] font-bold uppercase tracking-widest mt-0.5"
                >
                  {item.proformaNumber}
                </Text>
              </View>
            </View>

            <Text variant="p" className="text-foreground font-bold mb-1">
              {item.customerName}
            </Text>
            {item.description && (
              <Text
                variant="muted"
                className="text-xs line-clamp-1 mb-4 opacity-70"
              >
                {item.description}
              </Text>
            )}

            <View className="h-[1px] bg-border/50 mb-4" />

            <View className="flex-row justify-between items-center">
              <View className="flex-row items-center gap-2">
                <View className="p-1 bg-secondary/80 rounded-md">
                  <Clock color="#64748b" size={12} strokeWidth={2.5} />
                </View>
                <Text variant="muted" className="text-[11px] font-medium">
                  Issued: {dateStr}
                </Text>
              </View>

              <Pressable
                className="bg-primary/10 px-3.5 py-1.5 rounded-full border border-primary/20 flex-row items-center gap-1.5"
                onPress={(e) => {
                  e.stopPropagation();
                  // Handle share
                }}
              >
                <Send color="#ea580c" size={12} strokeWidth={2.5} />
                <Text className="text-primary text-[11px] font-bold uppercase tracking-tight">
                  Share
                </Text>
              </Pressable>
            </View>
          </View>
        </Card>
      </Pressable>
    );
  };

  return (
    <ScreenWrapper className="bg-background">
      <StandardHeader />

      <FlatList
        data={proformas}
        renderItem={renderProformaItem}
        keyExtractor={(item) => item.id}
        contentContainerStyle={{ padding: 20, paddingBottom: 150 }}
        showsVerticalScrollIndicator={false}
        onRefresh={onRefresh}
        refreshing={refreshing}
        onEndReached={loadMore}
        onEndReachedThreshold={0.5}
        ListHeaderComponent={
          <Button
            className="mb-6 h-12 rounded-[14px] bg-primary shadow-lg shadow-primary/30"
            onPress={() => nav.go("proforma/create")}
          >
            <Plus color="white" size={20} strokeWidth={3} />
            <Text className="text-white text-sm font-bold uppercase tracking-widest ml-1">
              Create New Proforma
            </Text>
          </Button>
        }
        ListFooterComponent={
          loadingMore ? (
            <ActivityIndicator color="#ea580c" className="py-4" />
          ) : null
        }
        ListEmptyComponent={
          !loading ? (
            <View className="py-20 items-center">
              <Text variant="muted">No proformas found</Text>
            </View>
          ) : (
            <View className="py-20">
              <ActivityIndicator size="large" color="#ea580c" />
            </View>
          )
        }
      />
    </ScreenWrapper>
  );
}