import { ActivityIndicator, Toast } from '@ant-design/react-native';
import { Ionicons } from '@expo/vector-icons';
import clsx from 'clsx';
import { BlurView } from 'expo-blur';
import { Link, Stack } from 'expo-router';
import React, { useCallback, useEffect, useRef, useState } from 'react';
import { Pressable, Text, TextInput, View } from 'react-native';
import Animated, { Extrapolation, interpolate, useAnimatedScrollHandler, useAnimatedStyle, useSharedValue } from 'react-native-reanimated';
import { useSafeAreaInsets } from 'react-native-safe-area-context';
import { StatusBadge } from '@/components/ui/status-badge';
import api from '@/utils/api';
import { getApiCache } from '@/utils/storage';
import type { ListResponse } from '@/utils/api';

export type CustomerLoanStatus = 'idle' | 'matched' | 'unmatch' | 'pending' | 'completed' | 'all' | undefined;
export const CustomerLoanStatusText: Record<NonNullable<CustomerLoanStatus>, string> = {
  all: '所有',
  idle: '待匹配',
  pending: '匹配中',
  matched: '已匹配',
  completed: '已完成',
  unmatch: '匹配失败',
};


export type Customer = {
  id: string;
  name: string;
  mobile: string;
  loan_status: CustomerLoanStatus;
  note: string;
  score?: string;
  updatetime: string;
};

const PAGE_SIZE = 15;
const CACHE_KEY = 'customer_first';

function CustomerCard({ item }: { item: Customer }) {
  return (
    <Pressable
      className="rounded-2xl border border-outline-variant bg-surface-container-lowest px-4 py-4 active:opacity-90 active:scale-[0.99]"
    >
      <View className="mb-3 flex-row items-start justify-between gap-3">
        <View className="flex-1 flex-row items-center gap-3">
          <View className="h-11 w-11 items-center justify-center rounded-full bg-primary-fixed">
            <Text className="text-base font-bold text-primary">{item.name[0]}</Text>
          </View>
          <View className="flex-1">
            <Text className="text-lg font-bold text-on-surface">{item.name}</Text>
            <Text className="mt-1 text-sm text-on-surface-variant">{item.mobile}</Text>
          </View>
        </View>
        <StatusBadge text={item.loan_status || ''} variant="secondary" />
      </View>

      <Text className="mb-2.5 text-sm leading-6 text-on-surface-variant">{item.note}</Text>

      <View className="mb-3 flex-row flex-wrap items-center gap-3">
        <View className="flex-row items-center gap-1">
          <Ionicons name="document-text-outline" size={16} color="#94a3b8" />
          <Text className="text-xs text-on-surface-variant">{item.loan_status}</Text>
        </View>
        {item.score ? (
          <View className="flex-row items-center gap-1">
            <Ionicons name="analytics-outline" size={16} color="#94a3b8" />
            <Text className="text-xs text-on-surface-variant">评分 {item.score}</Text>
          </View>
        ) : null}
        <Text className="ml-auto text-xs text-outline">{item.updatetime}</Text>
      </View>

      <View className="flex-row gap-3">
        <Pressable
          className="flex-1 items-center rounded-xl bg-primary-container py-2.5 active:opacity-88"
        >
          <Text className="text-sm font-bold text-on-primary">{item.loan_status}</Text>
        </Pressable>
        <Pressable
          className="flex-1 items-center rounded-xl bg-surface-container-high py-2.5 active:opacity-88"
        >
          <Text className="text-sm font-semibold text-on-surface">编辑资料</Text>
        </Pressable>
      </View>
    </Pressable>
  );
}

const renderCustomer = ({ item }: { item: Customer }) => <CustomerCard item={item} />;
const keyExtractor = (item: Customer) => item.id;

export default function CustomerScreens() {
  const [searchKey, setSearchKey] = useState('');
  const [list, setList] = useState<Customer[]>([]);
  const [loading, setLoading] = useState(true);
  const [activeStatus, setActiveStatus] = useState<CustomerLoanStatus>('idle');

  const startRef = useRef(0);
  const loanStatusRef = useRef<CustomerLoanStatus>('idle');
  const hasMoreRef = useRef(false);
  const loadingRef = useRef(false);
  const searchTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);

  const insets = useSafeAreaInsets();

  const scrollOffsetY = useSharedValue(0);
  const scrollHandler = useAnimatedScrollHandler((e) => {
    scrollOffsetY.value = e.contentOffset.y;
  });
  const headerStyle = useAnimatedStyle(() => ({
    opacity: interpolate(scrollOffsetY.value, [0, 24 + insets.top], [0, 1], Extrapolation.CLAMP),
  }));

  const load = useCallback(async (start: number, loanStatus: CustomerLoanStatus, q?: string) => {
    if (loadingRef.current) return;
    loadingRef.current = true;
    loanStatusRef.current = loanStatus;
    startRef.current = start;
    setLoading(true);

    if (start === 0 && !loanStatus && !q) {
      const cache = getApiCache().getObject<ListResponse<Customer>>(CACHE_KEY);
      if (cache) {
        setList(cache.list);
        startRef.current = cache.list.length;
        hasMoreRef.current = cache.list.length >= PAGE_SIZE;
        setLoading(false);
        loadingRef.current = false;
        return;
      }
    }

    try {
      const res = await api.post<ListResponse<Customer>>('customer/list', {
        start,
        size: PAGE_SIZE,
        loanStatus,
        q,
      });
      if (loanStatusRef.current !== loanStatus) return;
      const next = res?.list ?? [];
      if (start === 0 && !loanStatus && !q && next.length) {
        getApiCache().setObject(CACHE_KEY, res, 60);
      }
      hasMoreRef.current = next.length >= PAGE_SIZE;
      setList((prev) => (start === 0 ? next : prev.concat(next)));
      startRef.current = start + next.length;
      if (!next.length && start > 0) {
        Toast.offline('没有更多数据可加载');
      }
    } catch {
      Toast.fail('加载列表失败！');
    } finally {
      setLoading(false);
      loadingRef.current = false;
    }
  }, []);

  useEffect(() => {
    load(0, 'idle');
  }, [load]);

  const loadMore = useCallback(() => {
    if (!hasMoreRef.current || loadingRef.current) return;
    load(startRef.current, loanStatusRef.current, searchKey);
  }, [load, searchKey]);

  const handleSelectStatus = useCallback(
    (status: CustomerLoanStatus) => {
      const next = activeStatus === status ? undefined : status;
      setActiveStatus(next);
      load(0, next, searchKey);
    },
    [activeStatus, load, searchKey]
  );

  const handleSearch = useCallback(
    (k: string) => {
      setSearchKey(k);
      if (searchTimerRef.current) clearTimeout(searchTimerRef.current);
      searchTimerRef.current = setTimeout(() => {
        load(0, loanStatusRef.current, k);
      }, 600);
    },
    [load]
  );

  const handleReset = useCallback(() => {
    handleSearch('');
  }, [handleSearch]);

  useEffect(() => {
    return () => {
      if (searchTimerRef.current) clearTimeout(searchTimerRef.current);
    };
  }, []);

  const ListHeader = (
    <>
      <Text className="h-[44px] text-3xl font-extrabold tracking-tight text-on-surface">客户</Text>
      <Text className="mb-5 text-base leading-7 text-on-surface-variant">
        统一跟进客户资料、征信进度和产品匹配状态
      </Text>

      <View className="mb-3 flex-row items-center rounded-2xl bg-surface-container-low px-4 py-3">
        <Ionicons name="search-outline" size={20} color="#94a3b8" />
        <TextInput
          value={searchKey}
          onChangeText={handleSearch}
          placeholder="搜索客户姓名 / 手机号"
          placeholderTextColor="#94a3b8"
          className="ml-3 flex-1 p-0 text-base text-on-surface"
        />
        {searchKey.length > 0 ? (
          <Pressable hitSlop={8} onPress={handleReset}>
            <Ionicons name="close-circle" size={20} color="#94a3b8" />
          </Pressable>
        ) : null}
      </View>

      <View className="mb-5 flex-row flex-wrap gap-2">
        {Object.entries(CustomerLoanStatusText).map(([key, label]) => {
          const active = activeStatus === (key as CustomerLoanStatus);
          return (
            <Pressable
              key={key}
              onPress={() => handleSelectStatus(key as CustomerLoanStatus)}
              className={clsx('rounded-md px-1 border border-transparent active:opacity-84', {
                'border-primary-container': active,
              })}
            >
              <Text
                className={clsx('text-sm font-bold text-on-surface-variant', {
                  'text-primary': active,
                })}
              >
                {label}
              </Text>
            </Pressable>
          );
        })}
      </View>
    </>
  );

  const ListEmpty = !loading ? (
    <View className="items-center rounded-2xl border border-outline-variant bg-surface-container-lowest px-6 py-14">
      <Ionicons name="people-outline" size={44} color="#94a3b8" />
      <Text className="mt-4 text-base text-on-surface-variant">暂无匹配客户</Text>
    </View>
  ) : null;

  const ListFooter =
    loading && list.length > 0 ? (
      <View className="flex-row justify-center items-center mt-2">
        <ActivityIndicator />
        <Text className="ml-2 pb-4">加载中</Text>
      </View>
    ) : null;

  const ListInitialLoading =
    loading && list.length === 0 ? (
      <View className="flex-row justify-center items-center mt-2">
        <ActivityIndicator />
        <Text className="ml-2 pb-4">加载中</Text>
      </View>
    ) : null;

  return (
    <>
      <Animated.FlatList
        className="flex-1"
        // contentInset={{ top: insets.top, bottom: insets.bottom }}
        automaticallyAdjustContentInsets
        contentContainerStyle={{ paddingTop: insets.top + 12, paddingBottom: insets.bottom + 44 + 20, paddingHorizontal: 20 }}

        data={list}
        keyExtractor={keyExtractor}
        renderItem={renderCustomer}
        keyboardShouldPersistTaps="handled"
        showsVerticalScrollIndicator={false}
        ListHeaderComponent={ListHeader}
        ListEmptyComponent={ListInitialLoading ?? ListEmpty}
        ListFooterComponent={ListFooter}
        onEndReached={loadMore}
        onEndReachedThreshold={0.5}
        onScroll={scrollHandler}
        scrollEventThrottle={16}
      />
      <Stack.Screen options={{
        headerShown: true,
        headerTransparent: true,
        header: () => (
          <Animated.View style={headerStyle} className="border-b border-outline-variant/60 android:bg-surface-container-lowest/90">
            <BlurView tint="light" className="bg-background">
              <Text style={{ marginTop: insets.top }} className="pl-5 h-[44px] text-3xl font-extrabold tracking-tight text-on-surface">
                客户
              </Text>
            </BlurView>
          </Animated.View>
        ),
      }} />
      <Link asChild href="/customer/add" style={{bottom: insets.bottom + 44 + 12}} className="absolute pb-2 right-5">
        <Pressable
          className="h-14 w-14 items-center justify-center rounded-full bg-primary-container active:opacity-80 active:scale-[0.94]"
        >
          <Ionicons name="person-add" size={20} color="#ffffff" />
        </Pressable>
      </Link>
    </>
  );
}