import { useEffect, useState } from 'react';
import { Button, Card, Empty, Input, Select, Space, Spin, Tag, Modal, Form, message } from 'antd';
import { SearchOutlined } from '@ant-design/icons';
import { PointsMallAPI, PointsMallCategory, PointsMallOverview, PointsMallProduct, PointsMallProductsResponse } from '../api';

type SortKey = 'popular' | 'price_asc' | 'price_desc' | 'newest';

const MOCK_OVERVIEW: PointsMallOverview = {
  me: { points: 1280, level: 'Lv.2' },
  categories: [
    { id: 'all', name: '全部', sort: 0 },
    { id: 'digital', name: '虚拟权益', sort: 1 },
    { id: 'tool', name: '工具周边', sort: 2 },
    { id: 'gift', name: '礼品卡券', sort: 3 },
    { id: 'limited', name: '限时活动', sort: 4 }
  ],
  announcements: [],
  banners: [
    { id: 'b1', title: '本期活动', subtitle: 'Up to 25% Off', imageUrl: '', linkUrl: '' }
  ],
  promoEntries: [
    { id: 'p1', title: '促销活动', subtitle: '本周精选', linkUrl: '' },
    { id: 'p2', title: '积分任务', subtitle: '快速涨积分', linkUrl: '' }
  ]
};

const MOCK_PRODUCTS: PointsMallProduct[] = Array.from({ length: 12 }).map((_, i) => ({
  id: String(i + 1),
  categoryId: i % 2 === 0 ? 'digital' : 'tool',
  name: `商品 ${i + 1}`,
  subtitle: '这里是商品简短描述',
  coverUrl: '',
  pointsPrice: 199 + i * 10,
  stock: 99,
  sold: 12 + i,
  tags: i % 3 === 0 ? ['限时'] : i % 3 === 1 ? ['热卖'] : []
}));

interface ExchangeFormValues {
  recipientName: string;
  phone: string;
  province: string;
  city: string;
  district: string;
  address: string;
  zipCode?: string;
}

export default function PointsMallPage() {
  const [overviewLoading, setOverviewLoading] = useState(false);
  const [productsLoading, setProductsLoading] = useState(false);
  const [overview, setOverview] = useState<PointsMallOverview | null>(null);
  const [categories, setCategories] = useState<PointsMallCategory[]>([]);

  const [categoryId, setCategoryId] = useState<string>('all');
  const [q, setQ] = useState('');
  const [sort, setSort] = useState<SortKey>('popular');
  const [page, setPage] = useState(1);
  const [pageSize, setPageSize] = useState(24);
  const [productsRes, setProductsRes] = useState<PointsMallProductsResponse | null>(null);

  const [exchangeModalVisible, setExchangeModalVisible] = useState(false);
  const [selectedProduct, setSelectedProduct] = useState<PointsMallProduct | null>(null);
  const [pendingOrderId, setPendingOrderId] = useState<string | null>(null);
  const [exchangeLoading, setExchangeLoading] = useState(false);
  const [form] = Form.useForm<ExchangeFormValues>();

  const loadOverview = async () => {
    setOverviewLoading(true);
    try {
      const data = await PointsMallAPI.overview();
      setOverview(data);
      setCategories(data.categories || []);
      if (!data.categories?.some((c) => c.id === categoryId) && data.categories?.[0]?.id) {
        setCategoryId(data.categories[0].id);
      }
    } catch {
      message.error('获取积分信息失败，请稍后重试');
      setOverview({
        ...MOCK_OVERVIEW,
        me: { points: 0, level: 'Lv.0' }
      });
      setCategories(MOCK_OVERVIEW.categories);
    } finally {
      setOverviewLoading(false);
    }
  };

  const loadProducts = async () => {
    setProductsLoading(true);
    try {
      const res = await PointsMallAPI.products({
        categoryId: categoryId === 'all' ? undefined : categoryId,
        q,
        sort,
        page,
        pageSize
      });
      setProductsRes(res);
    } catch {
      const filtered = MOCK_PRODUCTS.filter((p) => (categoryId === 'all' ? true : p.categoryId === categoryId))
        .filter((p) => (q ? (p.name + p.subtitle).toLowerCase().includes(q.toLowerCase()) : true));
      setProductsRes({
        page,
        pageSize,
        total: filtered.length,
        items: filtered.slice((page - 1) * pageSize, page * pageSize)
      });
    } finally {
      setProductsLoading(false);
    }
  };

  useEffect(() => {
    loadOverview();
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  useEffect(() => {
    loadProducts();
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [categoryId, q, sort, page, pageSize]);

  const banner = overview?.banners?.[0];
  const promoEntries = overview?.promoEntries || [];

  const products = productsRes?.items || [];
  const total = productsRes?.total || 0;

  const handleExchangeClick = async (product: PointsMallProduct) => {
    if (userPoints < product.pointsPrice) return;

    setExchangeLoading(true);
    try {
      const res = await PointsMallAPI.exchangePrepare(product.id);
      setSelectedProduct(product);
      setPendingOrderId(res.orderId);
      setExchangeModalVisible(true);
      form.resetFields();
      setOverview((prev) => {
        if (!prev) return prev;
        return { ...prev, me: { ...prev.me, points: res.remainingPoints } };
      });
      message.success('积分扣减成功，请填写收件信息完成兑换');
    } catch (e: any) {
      message.error(e?.message || '兑换失败，请稍后重试');
    } finally {
      setExchangeLoading(false);
    }
  };

  const handleExchangeSubmit = async () => {
    if (!selectedProduct || !pendingOrderId) return;

    try {
      await form.validateFields();
      setExchangeLoading(true);

      await PointsMallAPI.exchangeSubmitShipping(pendingOrderId, form.getFieldsValue());

      message.success('兑换成功！我们将尽快为您安排发货');
      setExchangeModalVisible(false);
      setPendingOrderId(null);
      
      // 刷新积分余额
      loadOverview();
    } catch (error: any) {
      if (error?.errorFields) return;
      message.error(error?.message || '提交失败，请稍后重试');
    } finally {
      setExchangeLoading(false);
    }
  };

  const userPoints = overview?.me?.points || 0;
  const canAfford = selectedProduct ? userPoints >= selectedProduct.pointsPrice : false;

  return (
    <div className="page-container" style={{ maxWidth: 1400 }}>
      <div className="points-mall-hero">
        <div className="points-mall-header">
          <div className="points-mall-title-section">
            <h1 className="page-title stats-page-title">积分商城</h1>
            <p className="page-subtitle stats-page-subtitle">
              使用积分兑换权益、工具和活动礼包。积分通过 API 调用消费自动累积，1 美元 = 1000 积分。
            </p>
          </div>
          <div className="points-mall-balance-card">
            {overviewLoading ? (
              <Spin />
            ) : (
              <div className="points-balance-row">
                <div>
                  <div className="points-balance-label">我的积分</div>
                  <div className="points-balance-value">{userPoints.toLocaleString()}</div>
                </div>
                <Tag bordered={false} style={{ margin: 0, borderRadius: 999, background: 'var(--color-brand-soft)', color: 'var(--color-brand)' }}>
                  {String(overview?.me?.level || 'Lv.0')}
                </Tag>
              </div>
            )}
          </div>
        </div>
      </div>

      <Card className="points-mall-category-card" bodyStyle={{ padding: 0 }}>
        <div className="points-mall-category-body">
          <div className="points-mall-category-row">
            <span className="points-mall-category-label">商品分类</span>
            {categories.map((c) => (
              <Button
                key={c.id}
                size="small"
                type={c.id === categoryId ? 'primary' : 'default'}
                style={{ borderRadius: 999 }}
                onClick={() => {
                  setPage(1);
                  setCategoryId(c.id);
                }}
              >
                {c.name}
              </Button>
            ))}
          </div>
        </div>
      </Card>

      <div className="points-mall-banner-section">
        <div className="points-mall-banner-card">
          <div className="points-mall-banner-header">
            <div>
              <div className="points-mall-banner-title">{banner?.title || '本期活动'}</div>
              <div className="points-mall-banner-subtitle">{banner?.subtitle || 'Up to 25% Off'}</div>
            </div>
            <Button type="primary" style={{ borderRadius: 12, height: 40, fontWeight: 600 }}>
              查看活动
            </Button>
          </div>
          <div className="points-mall-banner-footer">banner 图片与跳转链接由后端配置</div>
        </div>

        <div className="points-mall-promo-grid">
          {promoEntries.slice(0, 2).map((p) => (
            <div key={p.id} className="points-mall-promo-card">
              <div style={{ minWidth: 0 }}>
                <div className="points-mall-promo-title">{p.title}</div>
                <div className="points-mall-promo-subtitle">{p.subtitle}</div>
            </div>
            <Button size="small" className="points-mall-exchange-btn">进入</Button>
          </div>
        ))}
          {promoEntries.length < 2 && (
            <div className="points-mall-promo-empty">促销入口由后端配置</div>
          )}
        </div>
      </div>

      <Card className="stats-page-chart-card">
        <div className="points-mall-filters-row">
          <Space size={10} wrap className="points-mall-filters-left">
            <Input
              value={q}
              onChange={(e) => {
                setPage(1);
                setQ(e.target.value);
              }}
              prefix={<SearchOutlined />}
              placeholder="搜索商品"
              allowClear
              className="points-mall-search-input"
            />
            <Select
              value={sort}
              className="points-mall-filter-select"
              onChange={(v: SortKey) => {
                setPage(1);
                setSort(v);
              }}
              options={[
                { value: 'popular', label: '热度优先' },
                { value: 'newest', label: '最新上架' },
                { value: 'price_asc', label: '积分从低到高' },
                { value: 'price_desc', label: '积分从高到低' }
              ]}
            />
            <Select
              value={pageSize}
              className="points-mall-filter-select-small"
              onChange={(v) => {
                setPage(1);
                setPageSize(v);
              }}
              options={[
                { value: 12, label: '每页 12' },
                { value: 24, label: '每页 24' },
                { value: 48, label: '每页 48' }
              ]}
            />
          </Space>
          <div className="points-mall-total-text">
            共 {total.toLocaleString()} 件商品
          </div>
        </div>

        {productsLoading ? (
          <Spin style={{ marginTop: 40, display: 'block' }} />
        ) : products.length === 0 ? (
          <Empty description="暂无商品" style={{ marginTop: 60 }} />
        ) : (
          <div className="points-mall-products-grid">
            {products.map((p) => (
              <div key={p.id} className="points-mall-product-card">
                <div className="points-mall-product-cover" />
                <div className="points-mall-product-body">
                  <div className="points-mall-product-header">
                    <div className="points-mall-product-info">
                      <div className="points-mall-product-name">{p.name}</div>
                      <div className="points-mall-product-desc">{p.subtitle}</div>
                    </div>
                    {p.tags?.length ? (
                      <Tag bordered={false} className="points-mall-product-tag">
                        {p.tags[0]}
                      </Tag>
                    ) : null}
                  </div>
                  <div className="points-mall-product-price-row">
                    <div>
                      <span className="points-mall-product-price">{Number(p.pointsPrice).toLocaleString()}</span>
                      <span className="points-mall-product-price-label">积分</span>
                    </div>
                    <Button
                      type="primary"
                      className="points-mall-exchange-btn points-mall-product-exchange-btn"
                      disabled={userPoints < p.pointsPrice}
                      onClick={() => handleExchangeClick(p)}
                    >
                      {userPoints < p.pointsPrice ? '积分不足' : '兑换'}
                    </Button>
                  </div>
                  <div className="points-mall-product-footer">
                    <span>库存 {p.stock}</span>
                    <span>已兑 {p.sold}</span>
                  </div>
                </div>
              </div>
            ))}
          </div>
        )}

        {!!productsRes && (
          <div className="points-mall-pagination">
            <Space size={10}>
              <Button disabled={page <= 1} onClick={() => setPage((v) => Math.max(1, v - 1))} className="points-mall-exchange-btn">
                上一页
              </Button>
              <Tag bordered={false} className="points-mall-pagination-tag">
                第 {page} 页
              </Tag>
              <Button
                disabled={page * pageSize >= total}
                onClick={() => setPage((v) => v + 1)}
                className="points-mall-exchange-btn"
              >
                下一页
              </Button>
            </Space>
          </div>
        )}
      </Card>

      {/* 兑换弹窗 */}
      <Modal
        title="兑换商品"
        open={exchangeModalVisible}
        onCancel={() => {
          setExchangeModalVisible(false);
          setPendingOrderId(null);
        }}
        footer={null}
        width={500}
        className="points-exchange-modal"
        destroyOnClose
      >
        {selectedProduct && (
          <>
            <div className="points-exchange-modal-header">
              <div className="points-mall-exchange-modal-title">{selectedProduct.name}</div>
              <div className="points-mall-exchange-modal-points">{selectedProduct.pointsPrice.toLocaleString()} 积分</div>
            </div>

            {!canAfford && (
              <div className="points-exchange-balance-warning">
                积分不足！当前余额：{userPoints.toLocaleString()} 积分，还需：{(selectedProduct.pointsPrice - userPoints).toLocaleString()} 积分
              </div>
            )}

            <Form form={form} layout="vertical" className="points-exchange-form">
              <Form.Item
                name="recipientName"
                label={<span className="points-exchange-form-label">收货人姓名</span>}
                rules={[{ required: true, message: '请输入收货人姓名' }]}
                className="points-exchange-form-item"
              >
                <Input placeholder="请输入收货人姓名" className="points-exchange-form-input" />
              </Form.Item>

              <Form.Item
                name="phone"
                label={<span className="points-exchange-form-label">手机号码</span>}
                rules={[
                  { required: true, message: '请输入手机号码' },
                  { pattern: /^1[3-9]\d{9}$/, message: '请输入正确的手机号码' }
                ]}
                className="points-exchange-form-item"
              >
                <Input placeholder="请输入手机号码" className="points-exchange-form-input" />
              </Form.Item>

              <div className="points-mall-address-grid">
                <Form.Item
                  name="province"
                  label={<span className="points-exchange-form-label">省份</span>}
                  rules={[{ required: true, message: '请选择省份' }]}
                  className="points-exchange-form-item points-exchange-form-item-small"
                >
                  <Select placeholder="省份" className="points-exchange-form-input">
                    <Select.Option value="北京市">北京市</Select.Option>
                    <Select.Option value="上海市">上海市</Select.Option>
                    <Select.Option value="广东省">广东省</Select.Option>
                    <Select.Option value="浙江省">浙江省</Select.Option>
                    <Select.Option value="江苏省">江苏省</Select.Option>
                  </Select>
                </Form.Item>

                <Form.Item
                  name="city"
                  label={<span className="points-exchange-form-label">城市</span>}
                  rules={[{ required: true, message: '请选择城市' }]}
                  className="points-exchange-form-item points-exchange-form-item-small"
                >
                  <Select placeholder="城市" className="points-exchange-form-input">
                    <Select.Option value="深圳市">深圳市</Select.Option>
                    <Select.Option value="广州市">广州市</Select.Option>
                    <Select.Option value="杭州市">杭州市</Select.Option>
                    <Select.Option value="南京市">南京市</Select.Option>
                  </Select>
                </Form.Item>

                <Form.Item
                  name="district"
                  label={<span className="points-exchange-form-label">区/县</span>}
                  rules={[{ required: true, message: '请选择区/县' }]}
                  className="points-exchange-form-item points-exchange-form-item-small"
                >
                  <Select placeholder="区/县" className="points-exchange-form-input">
                    <Select.Option value="南山区">南山区</Select.Option>
                    <Select.Option value="福田区">福田区</Select.Option>
                    <Select.Option value="宝安区">宝安区</Select.Option>
                  </Select>
                </Form.Item>
              </div>

              <Form.Item
                name="address"
                label={<span className="points-exchange-form-label">详细地址</span>}
                rules={[{ required: true, message: '请输入详细地址' }]}
                className="points-exchange-form-item"
              >
                <Input.TextArea placeholder="请输入详细地址（街道、门牌号等）" rows={3} className="points-exchange-form-input" />
              </Form.Item>

              <Form.Item
                name="zipCode"
                label={<span className="points-exchange-form-label">邮政编码（选填）</span>}
                className="points-exchange-form-item"
              >
                <Input placeholder="请输入邮政编码" className="points-exchange-form-input" />
              </Form.Item>

              <Button
                type="primary"
                className="points-exchange-submit-btn"
                onClick={handleExchangeSubmit}
                loading={exchangeLoading}
                disabled={!canAfford}
              >
                {canAfford ? '确认兑换' : '积分不足，无法兑换'}
              </Button>
            </Form>
          </>
        )}
      </Modal>
    </div>
  );
}