import React, { useState, useCallback } from "react";
import {
  View,
  Pressable,
  ActivityIndicator,
  FlatList,
  TextInput,
} 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 { User, Search, Building2, Plus } from "@/lib/icons";
import { ScreenWrapper } from "@/components/ScreenWrapper";
import { StandardHeader } from "@/components/StandardHeader";
import { EmptyState } from "@/components/EmptyState";
import { Button } from "@/components/ui/button";
import { api } from "@/lib/api";
import { useFocusEffect } from "expo-router";
import { useAuthStore } from "@/lib/auth-store";
import { useColorScheme } from "nativewind";
import { getPlaceholderColor } from "@/lib/colors";

interface Customer {
  id: string;
  displayName: string;
  email: string;
  phone: string;
  type: "INDIVIDUAL" | "COMPANY";
  createdAt: string;
}

const TYPE_FILTERS = [
  { key: "", label: "All" },
  { key: "INDIVIDUAL", label: "Individual" },
  { key: "COMPANY", label: "Company" },
];

export default function CustomersScreen() {
  const nav = useSirouRouter<AppRoutes>();
  const { colorScheme } = useColorScheme();
  const isDark = colorScheme === "dark";

  const [customers, setCustomers] = useState<Customer[]>([]);
  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 [search, setSearch] = useState("");
  const [typeFilter, setTypeFilter] = useState("");

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

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

        const query: Record<string, any> = { page: pageNum, limit: 10 };
        if (search.trim()) query.search = search.trim();
        if (typeFilter) query.type = typeFilter;

        const response = await api.customers.getAll({ query });
        const newData = response.data;

        if (isRefresh) {
          setCustomers(newData);
        } else {
          setCustomers((prev) =>
            pageNum === 1 ? newData : [...prev, ...newData],
          );
        }
        setHasMore(response.meta.hasNextPage);
        setPage(pageNum);
      } catch (err: any) {
        console.error("[Customers] Fetch error:", err);
        setHasMore(false);
      } finally {
        setLoading(false);
        setRefreshing(false);
        setLoadingMore(false);
      }
    },
    [search, typeFilter],
  );

  useFocusEffect(
    useCallback(() => {
      setPage(1);
      fetchCustomers(1);
    }, [fetchCustomers]),
  );

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

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

  const renderItem = ({ item }: { item: Customer }) => (
    <View className="px-[16px]">
      <Pressable onPress={() => nav.go("customers/[id]", { id: item.id })}>
        <Card className="rounded-xl border-border bg-card overflow-hidden mb-2">
          <View className="flex-row items-center px-3 py-3">
            <View className="w-10 h-10 rounded-lg bg-primary/10 items-center justify-center mr-3">
              {item.type === "COMPANY" ? (
                <Building2 color="#E46212" size={18} strokeWidth={2} />
              ) : (
                <User color="#E46212" size={18} strokeWidth={2} />
              )}
            </View>
            <View className="flex-1">
              <View className="flex-row items-center justify-between">
                <Text
                  className="text-foreground font-sans-bold text-sm flex-1 mr-2"
                  numberOfLines={1}
                >
                  {item.displayName}
                </Text>
                <View
                  className={`px-2 py-0.5 rounded-[4px] ${
                    item.type === "COMPANY" ? "bg-blue-500/10" : "bg-primary/10"
                  }`}
                >
                  <Text
                    className={`text-[8px] font-sans-bold uppercase tracking-widest ${
                      item.type === "COMPANY" ? "text-blue-600" : "text-primary"
                    }`}
                  >
                    {item.type === "COMPANY" ? "Company" : "Individual"}
                  </Text>
                </View>
              </View>
              {item.email || item.phone ? (
                <View className="flex-row items-center mt-0.5 gap-2">
                  {item.email ? (
                    <Text
                      className="text-muted-foreground text-[11px] font-sans-medium"
                      numberOfLines={1}
                    >
                      {item.email}
                    </Text>
                  ) : null}
                  {item.email && item.phone ? (
                    <Text className="text-muted-foreground text-[11px]">·</Text>
                  ) : null}
                  {item.phone ? (
                    <Text
                      className="text-muted-foreground text-[11px] font-sans-medium"
                      numberOfLines={1}
                    >
                      {item.phone}
                    </Text>
                  ) : null}
                </View>
              ) : null}
            </View>
          </View>
        </Card>
      </Pressable>
    </View>
  );

  return (
    <ScreenWrapper className="bg-background">
      <FlatList
        data={customers}
        renderItem={renderItem}
        keyExtractor={(item) => item.id}
        contentContainerStyle={{ paddingBottom: 150 }}
        showsVerticalScrollIndicator={false}
        onRefresh={onRefresh}
        refreshing={refreshing}
        onEndReached={loadMore}
        onEndReachedThreshold={0.5}
        ListHeaderComponent={
          <>
            <StandardHeader />
            <View className="px-[16px] pt-6">
              {/* Search */}
              <View className="flex-row items-center bg-card border border-border rounded-xl px-3 h-11 mb-3">
                <Search size={16} color="#94a3b8" strokeWidth={2} />
                <TextInput
                  className="flex-1 ml-2 text-foreground text-sm"
                  placeholder="Search by name, email or phone..."
                  placeholderTextColor={getPlaceholderColor(isDark)}
                  value={search}
                  onChangeText={setSearch}
                  autoCapitalize="none"
                />
              </View>

              <Button
                className="mb-4 h-10 rounded-lg bg-primary"
                onPress={() => nav.go("customers/create")}
              >
                <Plus color="#ffffff" size={18} strokeWidth={2.5} />
                <Text className="text-white text-[11px] font-sans-bold uppercase tracking-widest ml-2">
                  Create Customer
                </Text>
              </Button>

              {/* Type filter */}
              <View className="flex-row gap-2 mb-4">
                {TYPE_FILTERS.map((f) => (
                  <Pressable
                    key={f.key}
                    onPress={() => {
                      setTypeFilter(f.key);
                      setPage(1);
                    }}
                    className={`px-4 py-1.5 rounded-[4px] ${
                      typeFilter === f.key
                        ? "bg-primary"
                        : "bg-card border border-border"
                    }`}
                  >
                    <Text
                      className={`text-[9px] font-sans-bold uppercase tracking-widest ${
                        typeFilter === f.key
                          ? "text-white"
                          : "text-muted-foreground"
                      }`}
                    >
                      {f.label}
                    </Text>
                  </Pressable>
                ))}
              </View>
            </View>
          </>
        }
        ListFooterComponent={
          loadingMore ? (
            <ActivityIndicator color="#E46212" className="py-4" />
          ) : null
        }
        ListEmptyComponent={
          !loading ? (
            <EmptyState
              title={search ? "No matching customers" : "No customers yet"}
              centered
            />
          ) : (
            <View className="py-20">
              <ActivityIndicator size="large" color="#E46212" />
            </View>
          )
        }
      />
    </ScreenWrapper>
  );
}