import React, { useState, useEffect } from 'react';
import { Table, Button, Card, Space, Tag, Modal, Form, Input, InputNumber, Select, DatePicker, message, Descriptions, Image, Divider } from 'antd';
import { PlusOutlined, EditOutlined, DeleteOutlined, EyeOutlined, UndoOutlined, PlusCircleOutlined, MinusCircleOutlined } from '@ant-design/icons';
import dayjs from 'dayjs';
import { useAuthStore } from '../store/authStore';
import FileUpload from '../components/FileUpload';

const { Option } = Select;
const { TextArea } = Input;

interface DetailItem {
  id?: string;
  description: string;
  amount: number;
  attachments?: string[];
}

const PaymentRequestsPage: React.FC = () => {
  const { user } = useAuthStore();
  const [requests, setRequests] = useState<any[]>([]);
  const [loading, setLoading] = useState(false);
  const [modalVisible, setModalVisible] = useState(false);
  const [detailModalVisible, setDetailModalVisible] = useState(false);
  const [editingId, setEditingId] = useState<number | null>(null);
  const [selectedRecord, setSelectedRecord] = useState<any>(null);
  const [form] = Form.useForm();
  const [detailItems, setDetailItems] = useState<DetailItem[]>([]);
  const [exchangeRates, setExchangeRates] = useState<Record<string, number>>({});

  useEffect(() => {
    fetchRequests();
  }, []);

  const fetchRequests = async () => {
    setLoading(true);
    try {
      const res = await fetch('/api/payment-requests');
      const data = await res.json();
      if (data.success) {
        // 解析JSON字符串字段
        const parsedRequests = data.data.map((request: any) => ({
          ...request,
          detail_items: request.detail_items ? JSON.parse(request.detail_items) : [],
          attachments: request.attachments ? JSON.parse(request.attachments) : []
        }));
        setRequests(parsedRequests);
      }
    } catch (error) {
      console.error('获取付款申请列表失败:', error);
      message.error('获取付款申请列表失败');
    } finally {
      setLoading(false);
    }
  };

  const handleCreate = () => {
    setEditingId(null);
    setDetailItems([]);
    form.resetFields();
    form.setFieldsValue({
      payment_date: dayjs(),
      currency: 'CNY',
      applicant: user?.name || user?.username || '当前用户',
      attachments: []
    });
    setModalVisible(true);
  };

  const handleEdit = (record: any) => {
    setEditingId(record.id);
    setDetailItems(record.detail_items || []);
    form.setFieldsValue({
      ...record,
      payment_date: record.payment_date ? dayjs(record.payment_date) : null,
      attachments: record.attachments || []
    });
    setModalVisible(true);
  };

  const handleView = (record: any) => {
    setSelectedRecord(record);
    setDetailModalVisible(true);
  };

  const handleDelete = async (id: number) => {
    Modal.confirm({
      title: '确认删除',
      content: '确定要删除这条付款申请吗？',
      onOk: async () => {
        try {
          await fetch('/api/payment-requests/' + id, { method: 'DELETE' });
          message.success('删除成功');
          fetchRequests();
        } catch (error) {
          message.error('删除失败');
        }
      }
    });
  };

  const handleWithdraw = async (id: number) => {
    Modal.confirm({
      title: '确认撤回',
      content: '撤回后可重新编辑提交，确认撤回吗？',
      onOk: async () => {
        try {
          await fetch('/api/payment-requests/' + id + '/withdraw', { method: 'POST' });
          message.success('已撤回，可重新编辑');
          fetchRequests();
        } catch (error) {
          message.error('撤回失败');
        }
      }
    });
  };

  const handleSubmit = async () => {
    try {
      const values = await form.validateFields();
      const data = {
        ...values,
        payment_date: values.payment_date?.format('YYYY-MM-DD'),
        detail_items: detailItems,
        amount: detailItems.reduce((sum, item) => sum + (item.amount || 0), 0),
        applicant: user?.name || user?.username
      };
      const url = editingId ? '/api/payment-requests/' + editingId : '/api/payment-requests';
      const method = editingId ? 'PUT' : 'POST';
      const res = await fetch(url, {
        method,
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(data)
      });
      const result = await res.json();
      if (result.success) {
        message.success(editingId ? '更新成功' : '创建成功');
        setModalVisible(false);
        fetchRequests();
      } else {
        message.error(result.error || '操作失败');
      }
    } catch (error) {
      message.error('操作失败');
    }
  };

  const addDetailItem = () => setDetailItems([...detailItems, { description: '', amount: 0, attachments: [] }]);
  const updateDetailItem = (index: number, field: keyof DetailItem, value: any) => {
    const newItems = [...detailItems];
    newItems[index] = { ...newItems[index], [field]: value };
    setDetailItems(newItems);
  };
  const convertToCNY = (amount: number, curr: string): number => {
    if (curr === "CNY") return amount;
    const rateKey = curr + "_CNY";
    const rate = exchangeRates[rateKey] || 1;
    return amount * rate;
  };

  const removeDetailItem = (index: number) => setDetailItems(detailItems.filter((_, i) => i !== index));

  const getStatusTag = (status: string) => {
    const statusMap: Record<string, { color: string; text: string }> = {
      pending: { color: 'processing', text: '待审批' },
      approved: { color: 'success', text: '已批准' },
      rejected: { color: 'error', text: '已退回' },
      withdrawn: { color: 'default', text: '已撤回' },
      paid: { color: 'blue', text: '已付款' },
    };
    const config = statusMap[status] || { color: 'default', text: status };
    return <Tag color={config.color}>{config.text}</Tag>;
  };

  const formatAmount = (amount: number, currency: string = 'CNY') => {
    const symbols: Record<string, string> = { CNY: '¥', USD: '$', LAK: '₭', THB: '฿' };
    return (symbols[currency] || '¥') + (amount || 0).toLocaleString('zh-CN', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
  };

  // Format number with thousand separator for input display
  const formatNumberWithSeparator = (value: number | undefined, currency: string): string => {
    if (value === undefined || value === null) return '';
    const symbols: Record<string, string> = { CNY: '¥', USD: '$', LAK: '₭', THB: '฿' };
    const symbol = symbols[currency] || '¥';
    return symbol + value.toLocaleString('zh-CN', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
  };

  // Parse formatted string back to number
  const parseFormattedNumber = (value: string): number => {
    // Remove currency symbols and thousand separators
    const cleaned = value.replace(/[¥$₭฿,]/g, '');
    return parseFloat(cleaned) || 0;
  };

  const columns = [
    { title: '事由', dataIndex: 'reason', key: 'reason', ellipsis: true, render: (v: string, r: any) => <a onClick={() => handleView(r)}>{v}</a> },
    { title: '申请人', dataIndex: 'applicant', key: 'applicant', width: 80 },
    { title: '收款单位', dataIndex: 'payee', key: 'payee', width: 150, ellipsis: true },
    { title: '金额', dataIndex: 'amount', key: 'amount', width: 140, render: (v: number, r: any) => (
        <>
          <div>{formatAmount(v, r.currency)}</div>
          {r.currency !== 'CNY' && r.amount_cny && <div style={{ color: '#999', fontSize: 12 }}>≈ ¥{r.amount_cny.toLocaleString('zh-CN', {minimumFractionDigits: 2})}</div>}
        </>
      ) },
    { title: '付款日期', dataIndex: 'payment_date', key: 'payment_date', width: 100 },
    { title: '状态', dataIndex: 'status', key: 'status', width: 100, render: (status: string) => getStatusTag(status) },
    { title: '编号', dataIndex: 'request_code', key: 'request_code', width: 120 },
    {
      title: '操作', key: 'action', width: 250,
      render: (_: any, record: any) => (
        <Space wrap>
          <Button size="small" icon={<EyeOutlined />} onClick={() => handleView(record)}>详情</Button>
          {record.status === 'pending' && (
            <>
              <Button size="small" icon={<EditOutlined />} onClick={() => handleEdit(record)}>编辑</Button>
              <Button size="small" icon={<UndoOutlined />} onClick={() => handleWithdraw(record.id)}>撤回</Button>
            </>
          )}
          {(record.status === 'rejected' || record.status === 'withdrawn') && (
            <Button size="small" type="primary" icon={<EditOutlined />} onClick={() => handleEdit(record)}>编辑重提</Button>
          )}
          <Button size="small" danger icon={<DeleteOutlined />} onClick={() => handleDelete(record.id)}>删除</Button>
        </Space>
      )
    }
  ];

  const currency = Form.useWatch('currency', form);

  return (
    <div style={{ padding: 24 }}>
      <div style={{ marginBottom: 24 }}>
        <h2 style={{ marginBottom: 8 }}>付款申请</h2>
        <p style={{ color: '#888', marginBottom: 0 }}>管理对外付款申请</p>
      </div>

      <Card extra={<Button type="primary" icon={<PlusOutlined />} onClick={handleCreate}>新建付款申请</Button>}>
        <Table dataSource={requests} columns={columns} rowKey="id" loading={loading} pagination={{ pageSize: 20 }} size="middle" scroll={{ x: 1200 }} />
      </Card>

      <Modal title={editingId ? '编辑付款申请' : '新建付款申请'} open={modalVisible} onOk={handleSubmit} onCancel={() => setModalVisible(false)} width={900}>
        <Form form={form} layout="vertical">
          <Form.Item name="applicant" label="申请人">
            <Input disabled style={{ color: 'rgba(0,0,0,0.85)', backgroundColor: '#f5f5f5' }} />
          </Form.Item>
          
          <Form.Item name="payment_date" label="付款日期" rules={[{ required: true }]}>
            <DatePicker style={{ width: '100%' }} />
          </Form.Item>

          <Form.Item name="payee" label="收款单位" rules={[{ required: true }]}>
            <Input placeholder="收款单位/供应商名称" />
          </Form.Item>

          <Form.Item name="bank_account" label="银行账号">
            <Input placeholder="收款银行账号" />
          </Form.Item>

          <Form.Item name="bank_name" label="开户银行">
            <Input placeholder="开户银行名称" />
          </Form.Item>

          <Form.Item name="currency" label="币种" rules={[{ required: true }]}>
            <Select style={{ width: 200 }}>
              <Option value="CNY">人民币 (CNY)</Option>
              <Option value="USD">美元 (USD)</Option>
              <Option value="LAK">老挝基普 (LAK)</Option>
              <Option value="THB">泰铢 (THB)</Option>
            </Select>
          </Form.Item>

          <Form.Item name="reason" label="付款事由" rules={[{ required: true }]}>
            <TextArea rows={2} placeholder="付款原因" />
          </Form.Item>

          <Divider>付款明细</Divider>
          
          <div style={{ marginBottom: 16 }}>
            <Button type="dashed" icon={<PlusCircleOutlined />} onClick={addDetailItem}>添加明细</Button>
            <span style={{ marginLeft: 16, color: '#888' }}>
              合计: {formatAmount(detailItems.reduce((sum, item) => sum + (item.amount || 0), 0), currency)}
            </span>
          </div>

          {detailItems.map((item, index) => (
            <Card key={index} size="small" style={{ marginBottom: 16 }}>
              <div style={{ display: 'flex', gap: 16, flexWrap: 'wrap', alignItems: 'flex-start' }}>
                <div style={{ flex: 1, minWidth: 200 }}>
                  <label style={{ display: 'block', marginBottom: 4, color: '#666' }}>款项说明</label>
                  <Input value={item.description} onChange={(e) => updateDetailItem(index, 'description', e.target.value)} placeholder="款项说明" />
                </div>
                <div style={{ width: 150 }}>
                  <label style={{ display: 'block', marginBottom: 4, color: '#666' }}>金额</label>
                  <InputNumber value={item.amount} onChange={(v) => updateDetailItem(index, 'amount', v)} min={0} precision={2} style={{ width: '100%' }} placeholder="金额" />
                </div>
                <div style={{ flex: 2, minWidth: 300 }}>
                  <label style={{ display: 'block', marginBottom: 4, color: '#666' }}>凭证附件</label>
                  <FileUpload value={item.attachments || []} onChange={(urls) => updateDetailItem(index, 'attachments', urls)} maxCount={3} accept="image/*" />
                </div>
                <Button type="text" danger icon={<MinusCircleOutlined />} onClick={() => removeDetailItem(index)} style={{ marginTop: 24 }} />
              </div>
            </Card>
          ))}

          <Divider>主附件</Divider>
          <Form.Item name="attachments" label="整体凭证附件">
            <FileUpload maxCount={9} accept="image/*" />
          </Form.Item>
        </Form>
      </Modal>

      <Modal title="付款申请详情" open={detailModalVisible} onCancel={() => setDetailModalVisible(false)} footer={null} width={900}>
        {selectedRecord && (
          <>
            <Descriptions bordered column={2} size="small">
              <Descriptions.Item label="申请编号">{selectedRecord.request_code}</Descriptions.Item>
              <Descriptions.Item label="状态">{getStatusTag(selectedRecord.status)}</Descriptions.Item>
              <Descriptions.Item label="申请人">{selectedRecord.applicant}</Descriptions.Item>
              <Descriptions.Item label="付款日期">{selectedRecord.payment_date}</Descriptions.Item>
              <Descriptions.Item label="收款单位">{selectedRecord.payee}</Descriptions.Item>
              <Descriptions.Item label="银行账号">{selectedRecord.bank_account}</Descriptions.Item>
              <Descriptions.Item label="开户银行">{selectedRecord.bank_name}</Descriptions.Item>
              <Descriptions.Item label="金额">
                {formatAmount(selectedRecord.amount, selectedRecord.currency)}
                {selectedRecord.currency !== 'CNY' && selectedRecord.amount_cny && (
                  <span style={{ color: '#999', marginLeft: 8 }}>≈ ¥{selectedRecord.amount_cny.toLocaleString('zh-CN', {minimumFractionDigits: 2})}</span>
                )}
              </Descriptions.Item>
              <Descriptions.Item label="付款事由" span={2}>{selectedRecord.reason}</Descriptions.Item>
            </Descriptions>

            {selectedRecord.detail_items && selectedRecord.detail_items.length > 0 && (
              <>
                <Divider>付款明细</Divider>
                <Table 
                  dataSource={selectedRecord.detail_items} 
                  rowKey="id"
                  size="small"
                  pagination={false}
                  columns={[
                    { title: '款项说明', dataIndex: 'description', key: 'description' },
                    { title: '金额', dataIndex: 'amount', key: 'amount', render: (v: number) => formatAmount(v, selectedRecord.currency) },
                    { title: '附件', dataIndex: 'attachments', key: 'attachments', render: (v: string[]) => v?.length ? `${v.length}张` : '-' }
                  ]}
                />
              </>
            )}
            
            {selectedRecord.attachments && selectedRecord.attachments.length > 0 && (
              <>
                <Divider>整体凭证附件</Divider>
                <Image.PreviewGroup>
                  <div style={{ display: 'flex', flexWrap: 'wrap', gap: 8 }}>
                    {selectedRecord.attachments.map((url: string, index: number) => (
                      <Image key={index} src={url} width={100} height={100} style={{ objectFit: 'cover', borderRadius: 4 }} />
                    ))}
                  </div>
                </Image.PreviewGroup>
              </>
            )}
          </>
        )}
      </Modal>
    </div>
  );
};

export default PaymentRequestsPage;