package com.training.api;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.training.api.dto.CreateCustomerRequest;
import com.training.model.Customer;
import com.training.service.CustomerService;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;


@WebServlet("/api/customers/*") // 关键修改：使用通配符*来匹配路径参数
public class CustomerController extends HttpServlet {
    private final ObjectMapper objectMapper;
    private final CustomerService customerService;

    public CustomerController() {
        this.objectMapper = new ObjectMapper();
        this.customerService = new CustomerService();
    }


    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        try {
            resp.setContentType("application/json");
            resp.setCharacterEncoding("UTF-8");

            String pathInfo = req.getPathInfo(); // 获取 /api/customers 之后的路径部分，例如 "/1"

            if (pathInfo == null || pathInfo.equals("/")) {
                // 获取所有客户
                List<Customer> customers = customerService.findAll();
                objectMapper.writeValue(resp.getOutputStream(), customers);
            } else {
                // 尝试根据ID获取单个客户
                try {
                    long id = Long.parseLong(pathInfo.substring(1)); // 去掉开头的 '/'
                    Customer customer = customerService.findById(id);
                    if (customer != null) {
                        objectMapper.writeValue(resp.getOutputStream(), customer);
                    } else {
                        resp.setStatus(HttpServletResponse.SC_NOT_FOUND); // 404 Not Found
                        resp.getWriter().write("{\"error\": \"客户不存在\"}");
                    }
                } catch (NumberFormatException e) {
                    resp.setStatus(HttpServletResponse.SC_BAD_REQUEST); // 400 Bad Request
                    resp.getWriter().write("{\"error\": \"无效的客户ID格式\"}");
                }
            }
        } catch (Exception e) {
            resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            e.printStackTrace();
            resp.getWriter().write("{\"error\": \"获取客户信息失败: " + e.getMessage() + "\"}");
        }
    }


    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        try {
            resp.setContentType("application/json");
            resp.setCharacterEncoding("UTF-8");

            CreateCustomerRequest createCustomerRequest = objectMapper.readValue(req.getInputStream(), CreateCustomerRequest.class);

            Customer customer = customerService.create(createCustomerRequest);

            resp.setStatus(HttpServletResponse.SC_CREATED); // 201 Created
            objectMapper.writeValue(resp.getOutputStream(), customer);

        } catch (Exception e) {
            resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            e.printStackTrace();
            resp.getWriter().write("{\"error\": \"创建客户失败: " + e.getMessage() + "\"}");
        }
    }


    @Override
    protected void doPut(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        try {
            resp.setContentType("application/json");
            resp.setCharacterEncoding("UTF-8");

            String pathInfo = req.getPathInfo();
            // 检查路径是否包含ID，例如 "/1"
            if (pathInfo == null || !pathInfo.matches("/\\d+")) {
                resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
                resp.getWriter().write("{\"error\": \"请求URL必须包含有效的客户ID，例如 /api/customers/1\"}");
                return;
            }

            long customerId = Long.parseLong(pathInfo.substring(1)); // 解析ID
            CreateCustomerRequest updateRequest = objectMapper.readValue(req.getInputStream(), CreateCustomerRequest.class);

            Customer updatedCustomer = customerService.update(customerId, updateRequest);

            if (updatedCustomer != null) {
                objectMapper.writeValue(resp.getOutputStream(), updatedCustomer);
            } else {
                resp.setStatus(HttpServletResponse.SC_NOT_FOUND);
                resp.getWriter().write("{\"error\": \"要更新的客户不存在\"}");
            }

        } catch (Exception e) {
            resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            e.printStackTrace();
            resp.getWriter().write("{\"error\": \"更新客户失败: " + e.getMessage() + "\"}");
        }
    }


    @Override
    protected void doDelete(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        try {
            resp.setContentType("application/json");
            resp.setCharacterEncoding("UTF-8");

            String pathInfo = req.getPathInfo();
            if (pathInfo == null || !pathInfo.matches("/\\d+")) {
                resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
                resp.getWriter().write("{\"error\": \"请求URL必须包含有效的客户ID，例如 /api/customers/1\"}");
                return;
            }

            long customerId = Long.parseLong(pathInfo.substring(1));
            boolean deleted = customerService.deleteById(customerId);

            if (deleted) {
                resp.setStatus(HttpServletResponse.SC_NO_CONTENT); // 204 No Content
            } else {
                resp.setStatus(HttpServletResponse.SC_NOT_FOUND);
                resp.getWriter().write("{\"error\": \"要删除的客户不存在\"}");
            }

        } catch (Exception e) {
            resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            e.printStackTrace();
            resp.getWriter().write("{\"error\": \"删除客户失败: " + e.getMessage() + "\"}");
        }
    }
}