package com.wangkai.servlet;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Method;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Properties;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.wangkai.annotation.MyController;
import com.wangkai.annotation.MyRequestMapping;

@SuppressWarnings("serial")
public class MyDispatcherServlet extends HttpServlet {
	private Properties properties =new Properties();
	private List<String> classNames=new ArrayList<String>();
	private Map<String, Object>ioc=new HashMap<String, Object>();
	private Map<String,Method> handlerMapping = new HashMap<String, Method>();
	private Map<String ,Object>controllerMap=new HashMap<String, Object>();
    public void init(ServletConfig config) {
    	//加载配置文件
    	doLoadConfig(config.getInitParameter("contextConfigLocation"));
    	//初始化所有相关联的类 扫面用户设定的包下边所有的类
    	doScanner(properties.getProperty("scanPackage"));
    	//拿到扫描到的类 通过反射机制 实例化并且放到IOC容器中
    	doInstance();
    	//初始化handlermapping
    	initHandlerMapping();
    }
    private void doInstance() {
    	if(classNames.isEmpty()) {
    		return;
    	}
    	for (String className : classNames) {
    		try {
				//将类搞出来，反射来实例化 
    			Class<?>clazz=Class.forName(className);
    			if(clazz.isAnnotationPresent(MyController.class)) {
    				ioc.put(toLowerFirstWord(clazz.getSimpleName()), clazz.newInstance());
    			}else {
					continue;
				}
			} catch (Exception e) {
				e.printStackTrace();
				continue;
			}
			
		}
    }
    private void initHandlerMapping() {
    	if(ioc.isEmpty()) {
    		return;
    	}
    	try {
    		for (Entry<String,Object> entry : ioc.entrySet()) {
    			Class<? extends Object> clazz=entry.getValue().getClass();
    			if(!clazz.isAnnotationPresent(MyController.class)) {
    				continue;
    			}
    			//拼接url时 是controller头的URL拼上方法的URL
    			String baseUrl="";
    			if(clazz.isAnnotationPresent(MyRequestMapping.class)) {
    				MyRequestMapping annotation=clazz.getAnnotation(MyRequestMapping.class);
    				baseUrl=annotation.value();
    			}
    			Method[] methods=clazz.getMethods();
    			for (Method method : methods) {
					if(!method.isAnnotationPresent(MyRequestMapping.class)) {
						continue;
					}
					MyRequestMapping annotation=method.getAnnotation(MyRequestMapping.class);
					String url=annotation.value();
					url=(baseUrl+"/"+url).replaceAll("/+", "/");
					handlerMapping.put(url, method);
					controllerMap.put(url, clazz.newInstance());
					System.out.println(url+","+method);
				}
    			
			}
    	}catch (Exception e) {
			e.printStackTrace();
		}
    }
    private String toLowerFirstWord(String name) {
    	char[] charArray=name.toCharArray();;
    	charArray[0]+=32;
    	return String.copyValueOf(charArray);
    }
    private void doLoadConfig(String location) {
    	//吧web.xml中的contextconfiglocation对应的value值得文件加载到流里面
    	InputStream resourceAsStream=this.getClass().getClassLoader().getResourceAsStream(location);
    	try {
			//用properties文件架子啊文件里的内容
    		properties.load(resourceAsStream);
		} catch (Exception e) {
				e.printStackTrace();
		}finally {
			if(null!=resourceAsStream) {
				try {
					resourceAsStream.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
    }
    private void doScanner(String packageName) {
    	URL url=this.getClass().getClassLoader().getResource("/"+packageName.replaceAll("\\.", "/"));
    	File dir=new File(url.getFile()) ;
    	for (File file : dir.listFiles()) {
			if(file.isDirectory()) {
				doScanner(packageName+"."+file.getName());
			}else {
				String className=packageName+"."+file.getName().replace(".class", "");
				classNames.add(className);
			}
		}
    }
    protected void doGet(HttpServletRequest req,HttpServletResponse res) {
    	try {
			this.doPost(req,res);
		} catch (Exception e) {
		}
    }
    protected void doPost(HttpServletRequest req, HttpServletResponse res) {
    	try {
			doDispatch(req, res);
		} catch (Exception e) {
		}
    }
      private void doDispatch(HttpServletRequest req,HttpServletResponse res) throws IOException {
    	  if(handlerMapping.isEmpty()) {
    		  return;
    	  }
    	  String url=req.getRequestURI();
    	  String contextPath=req.getContextPath();
    	  
    	  url=url.replace(contextPath, "").replaceAll("/+", "/");
    	  if(!this.handlerMapping.containsKey(url)) {
    		  res.getWriter().write("404");
    		  return;
    	  }
    	  Method method =this.handlerMapping.get(url);
    	  //获取方法的参数列表
    	  Class<?>[]paramterTypes = method.getParameterTypes();
    	  //获取请求的参数
    	  Map<String, String[]>paramterMap=req.getParameterMap();
    	  //保存请求的参数
    	  Object[] paramObjects = new Object[paramterTypes.length];
    	  
    	  //方法的参数列表
          for (int i = 0; i < paramObjects.length; i++) {
			//根据参数名称 做某些处理
        	  String requestParam=paramterTypes[i].getSimpleName();
        	  if(requestParam.equals("HttpServletRequest")) {
        		  paramObjects[i]=req;
        		  continue;
        	  }
        	  if (requestParam.equals("HttpServletResponse")){  
        		  paramObjects[i]=res;
                    continue;  
                }
        	  
        	  if(requestParam.equals("String")){
                  for (Entry<String, String[]> param : paramterMap.entrySet()) {
                   String value =Arrays.toString(param.getValue()).replaceAll("\\[|\\]", "").replaceAll(",\\s", ",");
                   paramObjects[i]=value;
                 }
                }
          }    	
          try {
			method.invoke(this.controllerMap.get(url), paramObjects);
		} catch (Exception e) {
			// TODO: handle exception
		}
      }
      
}