/**
 * 采购申请路由
 * 遵循设计方案：采购-付款-物流-退库一体化流程设计方案.md
 * 章节：二、采购申请页面改造
 * 
 * 简化后的采购申请：
 * - 不再录入供应商（询价前未知）
 * - 不再录入商品明细（询价后确定）
 * - 仅填写需求描述和预计金额
 * - 审批通过后自动生成订单草稿
 */
const express = require('express');
const db = require('../db');
const { authenticate, requireAdmin } = require('../middleware/auth');

const router = express.Router();

/**
 * 获取采购申请列表
 * 遵循设计方案：支持按项目、状态筛选
 */
router.get('/', async (req, res) => {
  try {
    const { project_id, status } = req.query;
    let query = `
      SELECT pr.*, p.name as project_name 
      FROM purchase_requests pr
      LEFT JOIN projects p ON pr.project_id = p.id
    `;
    const params = [];
    
    if (project_id) {
      query += ' WHERE pr.project_id = $1';
      params.push(project_id);
    }
    if (status) {
      query += project_id ? ' AND pr.status = $1' : ' WHERE pr.status = $2';
      params.push(status);
    }
    
    query += ' ORDER BY pr.created_at DESC';
    
    const result = await db.query(query, params);
    
    const data = result.rows.map(row => ({
      ...row,
      request_code: row.request_code
    }));
    
    res.json({
      success: true,
      data: data,
      count: data.length
    });
  } catch (error) {
    console.error('获取采购申请列表失败:', error);
    res.status(500).json({
      success: false,
      message: '获取采购申请列表失败',
      error: process.env.NODE_ENV === 'development' ? error.message : '操作失败'
    });
  }
});

/**
 * 获取采购申请详情
 * 遵循设计方案：简化后不再返回商品明细
 */
router.get('/:id', async (req, res) => {
  try {
    const { id } = req.params;
    
    const requestResult = await db.query(`
      SELECT pr.*, p.name as project_name 
      FROM purchase_requests pr
      LEFT JOIN projects p ON pr.project_id = p.id
      WHERE pr.id = $1
    `, [id]);
    
    if (requestResult.rows.length === 0) {
      return res.status(404).json({ success: false, message: '采购申请不存在' });
    }
    
    const purchaseRequest = requestResult.rows[0];
    // request_code is already in the table, no need to alias from code
    
    res.json({
      success: true,
      data: purchaseRequest
    });
  } catch (error) {
    console.error('获取采购申请详情失败:', error);
    res.status(500).json({
      success: false,
      message: '获取采购申请详情失败',
      error: process.env.NODE_ENV === 'development' ? error.message : '操作失败'
    });
  }
});

/**
 * 创建采购申请
 * 遵循设计方案：二、采购申请页面改造
 * 简化后的字段：
 * - purchase_type: 采购类型（项目采购/库存采购）
 * - project_id: 关联项目（项目采购必填）
 * - brief_description: 事由描述
 * - total_amount: 预计金额
 * - currency: 币种
 * - expected_date: 需求日期
 * - remark: 备注
 * - attachments: 附件
 */
router.post('/', async (req, res) => {
  try {
    const {
      project_id, total_amount, currency,
      purchase_type, remark
    } = req.body;
    
    const date = new Date();
    const requestCode = `PUR-${date.getFullYear()}${String(date.getMonth() + 1).padStart(2, '0')}${String(date.getDate()).padStart(2, '0')}-${String(Math.floor(Math.random() * 1000)).padStart(3, '0')}`;
    
    const result = await db.query(`
      INSERT INTO purchase_requests 
      (request_code, project_id, purchase_type, total_amount, currency, 
       status, remarks, created_at, updated_at)
      VALUES ($1, $2, $3, $4, $5, $6, $7, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)
       RETURNING id`,
      [requestCode, project_id, purchase_type || 'inventory', total_amount || 0, currency || 'CNY', 
        'pending', remark]);
    
    res.json({
      success: true,
      message: '采购申请创建成功',
      data: { id: (result.rows[0]?.id || result.rows?.[0]?.id), request_code: requestCode }
    });
  } catch (error) {
    console.error('创建采购申请失败:', error);
    res.status(500).json({
      success: false,
      message: '创建采购申请失败',
      error: process.env.NODE_ENV === 'development' ? error.message : '操作失败'
    });
  }
});

/**
 * 更新采购申请
 * 遵循设计方案：简化后不再处理商品明细
 */
router.put('/:id', async (req, res) => {
  try {
    const { id } = req.params;
    const {
      project_id, total_amount, currency,
      purchase_type, remark
    } = req.body;
    
    const result = await db.query(`
      UPDATE purchase_requests 
      SET project_id = $1, total_amount = $2, currency = $3, 
          purchase_type = $4, remarks = $5, updated_at = CURRENT_TIMESTAMP
      WHERE id = $6
    `, [project_id, total_amount, currency || 'CNY', 
        purchase_type || 'inventory', remark, id]);
    
    if (result.rowCount === 0) {
      return res.status(404).json({ success: false, message: '采购申请不存在' });
    }
    
    res.json({
      success: true,
      message: '采购申请更新成功'
    });
  } catch (error) {
    console.error('更新采购申请失败:', error);
    res.status(500).json({
      success: false,
      message: '更新采购申请失败',
      error: process.env.NODE_ENV === 'development' ? error.message : '操作失败'
    });
  }
});

/**
 * 删除采购申请
 */
router.delete('/:id', async (req, res) => {
  try {
    const { id } = req.params;
    
    const result = await db.query('DELETE FROM purchase_requests WHERE id = $1', [id]);
    
    if (result.rowCount === 0) {
      return res.status(404).json({ success: false, message: '采购申请不存在' });
    }
    
    res.json({
      success: true,
      message: '采购申请删除成功'
    });
  } catch (error) {
    console.error('删除采购申请失败:', error);
    res.status(500).json({
      success: false,
      message: '删除采购申请失败',
      error: process.env.NODE_ENV === 'development' ? error.message : '操作失败'
    });
  }
});

/**
 * 提交审批
 * 遵循设计方案：状态从 pending_edit 变为 pending
 */
router.post('/:id/submit', async (req, res) => {
  try {
    const { id } = req.params;
    
    const result = await db.query(
      'UPDATE purchase_requests SET status = $1, updated_at = CURRENT_TIMESTAMP WHERE id = $2', 
      ['pending', id]
    );
    
    if (result.rowCount === 0) {
      return res.status(404).json({ success: false, message: '采购申请不存在' });
    }
    
    res.json({ success: true, message: '提交成功' });
  } catch (error) {
    console.error('提交采购申请失败:', error);
    res.status(500).json({ success: false, message: '提交采购申请失败' });
  }
});

/**
 * 审批通过
 * 遵循设计方案：一、流程设计 - 审批通过后自动生成订单草稿
 * 章节：1.2 流程节点说明
 * - 状态变为 approved
 * - 自动创建采购订单草稿（purchase_orders表）
 */
router.post('/:id/approve', async (req, res) => {
  try {
    const { id } = req.params;
    
    const requestResult = await db.query('SELECT * FROM purchase_requests WHERE id = $1', [id]);
    if (requestResult.rows.length === 0) {
      return res.status(404).json({ success: false, message: '采购申请不存在' });
    }
    
    const purchaseRequest = requestResult.rows[0];
    
    await db.query('BEGIN TRANSACTION');
    
    try {
      await db.query(
        'UPDATE purchase_requests SET status = $1, updated_at = CURRENT_TIMESTAMP WHERE id = $2',
        ['approved', id]
      );
      
      const orderCode = 'PO' + new Date().toISOString().slice(0, 10).replace(/-/g, '') + 
                        String(Math.floor(Math.random() * 10000)).padStart(4, '0');
      
      const orderResult = await db.query(`
        INSERT INTO purchase_orders 
        (code, purchase_request_id, project_id, estimated_amount, currency, status, created_by, created_at, updated_at)
        VALUES ($1, $2, $3, $4, $5, $6, $7, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)
       RETURNING id`,
      [orderCode, id, purchaseRequest.project_id, purchaseRequest.total_amount, 
          purchaseRequest.currency || 'CNY', 'draft', purchaseRequest.created_by || 1]);
      
      await db.query('COMMIT');
      
      res.json({ 
        success: true, 
        message: '审批通过成功，已自动生成采购订单草稿',
        data: { order_id: orderResult.rows[0]?.id, order_code: orderCode }
      });
    } catch (innerError) {
      await db.query('ROLLBACK');
      throw innerError;
    }
  } catch (error) {
    console.error('审批采购申请失败:', error);
    res.status(500).json({ success: false, message: '审批采购申请失败' });
  }
});

/**
 * 驳回
 * 遵循设计方案：状态从 pending 变为 pending_edit
 */
router.post('/:id/reject', async (req, res) => {
  try {
    const { id } = req.params;
    
    const result = await db.query(
      'UPDATE purchase_requests SET status = $1, updated_at = CURRENT_TIMESTAMP WHERE id = $2', 
      ['pending', id]
    );
    
    if (result.rowCount === 0) {
      return res.status(404).json({ success: false, message: '采购申请不存在' });
    }
    
    res.json({ success: true, message: '驳回成功' });
  } catch (error) {
    console.error('驳回采购申请失败:', error);
    res.status(500).json({ success: false, message: '驳回采购申请失败' });
  }
});

/**
 * 撤回
 * 遵循设计方案：状态从 pending 变为 withdrawn
 */
router.post('/:id/withdraw', async (req, res) => {
  try {
    const { id } = req.params;
    
    const result = await db.query(
      'UPDATE purchase_requests SET status = $1, updated_at = CURRENT_TIMESTAMP WHERE id = $2', 
      ['withdrawn', id]
    );
    
    if (result.rowCount === 0) {
      return res.status(404).json({ success: false, message: '采购申请不存在' });
    }
    
    res.json({ success: true, message: '撤回成功' });
  } catch (error) {
    console.error('撤回采购申请失败:', error);
    res.status(500).json({ success: false, message: '撤回采购申请失败' });
  }
});

/**
 * 执行（已废弃，保留向后兼容）
 * 遵循设计方案：简化后不再使用此接口
 */
router.post('/:id/execute', async (req, res) => {
  try {
    const { id } = req.params;
    
    await db.query(
      'UPDATE purchase_requests SET status = $1, updated_at = CURRENT_TIMESTAMP WHERE id = $2', 
      ['executed', id]
    );
    
    res.json({ success: true, message: '执行成功' });
  } catch (error) {
    console.error('执行采购申请失败:', error);
    res.status(500).json({ success: false, message: '执行采购申请失败' });
  }
});

module.exports = router;