#include<bits/stdc++.h>

 #include<unistd.h>

 #include<stdio.h>

 #include<sys/types.h>

 #include<pwd.h>

 #include<time.h>

 #include<dirent.h>

 #include<stdlib.h>

 #include<sys/stat.h>

 #include<fcntl.h>

 #include <grp.h>

   #include <sys/wait.h>

 #include<memory.h>

 using namespace std;

 #define MAX_LINE 80

 #define MAX_NAME_LEN 50

 #define MAX_PATH_LEN 1000

 int cmd_cnt;

 char *cmd_array[MAX_LINE/+];

 string st;

 void mytime(){

     int weekday;

     int month;

     time_t tvar;

     struct tm *tp;

     time(&tvar);

     tp=localtime(&tvar);//获取本地时间

     weekday=tp->tm_wday;

     switch(weekday){//根据不同的值打印不同的星期

     case :

         printf("Mon ");

         break;

     case :

         printf("Tues ");

         break;

     case :

         printf("Wed ");

         break;

     case :

         printf("Thur ");

         break;

     case :

         printf("Fri ");

         break;

     case :

         printf("Sat ");

         break;

     case :

         printf("Sun ");

         break;

     default:

         break;

     }

     month=+tp->tm_mon;//必须要加1，经过查阅资料：tm_mon比实际的值少了1

     switch(month){//根据不同的值打印月份名

     case :

         printf("Jan ");

         break;

     case :

         printf("Feb ");

         break;

     case :

         printf("Mar ");

         break;

     case :

         printf("Apr ");

         break;

     case :

         printf("May ");

         break;

     case :

         printf("Jun ");

         break;

     case :

         printf("Jul ");

         break;

     case :

         printf("Aug ");

         break;

     case :

         printf("Sep ");

         break;

     case :

         printf("Oct ");

         break;

     case :

         printf("Nov ");

         break;

     case :

         printf("Dec ");

         break;

     default:

         break;

     }

     printf("%d ",tp->tm_mday);//日期

     printf("%d:",tp->tm_hour);//小时

     printf("%d:",tp->tm_min);//分钟

     printf("%d ",tp->tm_sec);//秒

     printf("CST ");//CST，意思是China Standard Time

     printf("%d\n",+tp->tm_year);//必须加上1900，返回的值并不是完整的年份，比真实值少了1900

 }

 void welcome(){

     //如下是欢迎信息

     //为了是程序更友好，加入了颜色

     //颜色是紫色，背景色与shell相同

     printf("\e[32mwelcome to myshell\e[0m\n");

     printf("\e[32mit's a Lunix-like shell program made by us\e[0m\n");

     printf("\e[32mhope you have a good time with it :-)\e[0m\n");

 }

 void mypwd(){

     char pathname[MAX_PATH_LEN];

     if(getcwd(pathname,MAX_PATH_LEN)){//获取路径名

         printf("%s\n",pathname);

     }

     else{//如果出错

         perror("myshell: getcwd");//报错

         exit();

     }

 }

 void myquit(){

     printf("Thanks for your using，bye-bye！\n");

     sleep();//暂停1s，看上去视觉效果好一些

     exit();

 }

 void exit(){

    exit();

 }

 void myclr(){

     cout << "\033[2J";

     cout << "\033[H";

 }

 void printprompt(){//实现命令提示符

     char hostname[MAX_NAME_LEN];

     char pathname[MAX_PATH_LEN];

     struct passwd *pwd;

     pwd=getpwuid(getuid());

     gethostname(hostname,MAX_NAME_LEN);

     printf("\e[34m%s@%s:\e[0m",pwd->pw_name,hostname);

         printf("$");

 }

 //*****************************************************获得文件权限属性

 void getPower(mode_t mod)

 {

   for(int n=; n>=; n--)

   {

       if(mod&(<<n))//移位运算,1左移位n位

       {

           switch(n%)

           {

           case :

               printf("r");

               break;

           case :

               printf("w");

               break;

           case :

               printf("x");

               break;

           default:

               break;

           }

       }

       else

       {

           printf("-");

       }

         }

 }

 void cat(string filename){

   ifstream fin( filename);

   char  str[];

   while ( fin.getline(str,) )

   {

     cout  << str << endl;

   }

 }

 void ls(string allstr,string substr){

 /******************************ls*************************

 *

 *dirName[]   :store single filename

 *dir         :point to currnt directory

 *rent        :指针变量

 *st          :文件基本操作

 **********************************************************/

 struct stat st;

 char dirName[];

 DIR *dir;

 struct dirent *rent;//struct

 dir = opendir(".");

   if(allstr== "ls"){

     if(dir != NULL)

     {

       while((rent=readdir(dir)))

       {

         strcpy(dirName,rent->d_name);

         if (dirName[]!='.' && dirName)

         {

           cout << dirName<<'\t';

         }

       }

     }

     cout << endl;

   }

   else if(dir == NULL)

   {

       cout << "*****empty*****"<<endl;

   }

   else if(allstr != "ls -l")

   {

     cout << substr+":  "+ "unrecognized option "+"'"+allstr.substr(substr.length())+"'"<<endl;

     cout << "Try 'ls -l' "<<endl;

   }

   /******************************************ls -l*************************/

   else if(allstr == "ls -l")

   {

     while( rent = readdir(dir) )

     {

       strcpy(dirName,rent->d_name);

       if (dirName[]!='.' && dirName)

       {

         if(- != stat(rent->d_name, &st) )//get fileInfomation from filename p->d_name and save it in structure stat

         {

           getPower(st.st_mode);        //get r-w-d

           cout <<" "<<st.st_nlink<<" ";//get number of file links

           cout <<" "<<getpwuid(st.st_uid)->pw_name<<" ";//owner name

           cout <<getgrgid(st.st_gid)->gr_name<<'\t'; //group name

           cout << st.st_size<<'\t';  //get total size , in bytes

           //printf 12 char and align = left

           printf("%.12s  ",+ctime(&st.st_mtime));   //the last time of changing file

           cout << dirName;

           cout << endl;

         }

       }

     }

   }

   closedir(dir);

 }

 //****************************************************获得输入字符

 string strInput()

 {

   string str;

   string res;

   char c;

   while( (c = getchar()) != '\n')

     str += c;

   vector<string> arr;

   istringstream istr(str);

   string word;

   while(istr>>word) {

       arr.push_back(word);//添加元素到尾部

   }

   for(int i=; i<arr.size(); i++) {

     if(i != arr.size() - )

         res += arr[i]+" ";

     else

       res += arr[i];

   }

   return res;

 }

 ///////////////////////////////////////////////////////////help命令

 void print_manual(){

     printf("welcome to the manual of myshell, hope it's useful for you\n");

     printf("the following are the BUILT-IN commands supported by myshell\n");

     printf("\n");

     printf("exit:      exit                            quit the shell directly\n");

     printf("clr:       clr                             clear the screen\n");

     printf("time:      time                            show the current time in an elegant format\n");

     printf("myshell:   myshell [filename]              execute a batchfile\n");

     printf("quit:      quit                            quit the shell with thank-you\n");

     printf("pwd:       pwd                             print the current working directory\n");

     printf("help:      help/help [command]             show the manual of help/get help info of a sepcified command\n");

 }

 void print_cmdinfo(string cmdname){

      if(cmdname=="exit"){

         printf("usage:quit the shell directly\n");

         printf("options            descriptions\n");

         printf("none               see the manual,plz\n");

     }

     else if(cmdname=="pwd"){

         printf("usage:print the current working directory\n");

         printf("options            descriptions\n");

         printf("none               see the manual,plz\n");

     }

     else if(cmdname=="time"){

         printf("usage:show the current time in an elegant format\n");

         printf("options            descriptions\n");

         printf("none               see the manual,plz\n");

     }

     else if(cmdname=="clr"){

         printf("usage:clear screen\n");

         printf("options            descriptions\n");

         printf("none               see the manual,pls\n");

     }

     else if(cmdname=="myshell"){

         printf("usage:execute a batchfile\n");

         printf("options            descriptions\n");

         printf("none               see the manual,plz\n");

     }

     else if(cmdname=="help"){

         printf("usage:show the manual of help/get help info of a sepcified command\n");

         printf("options            descriptions\n");

         printf("none               see the manual,plz\n");

     }

     else if(cmdname=="quit"){

         printf("usage:quit the shell with thank-you information\n");

         printf("options            descriptions\n");

         printf("none               see the manual,plz\n");

     }

     else {//如果有错

         printf("myshell: help: Invalid use of help command\n");//打印提示信息

     }

 }

 void myhelp(){

     if(cmd_cnt==){//如果是不带参数的help

         print_manual();//调用子函数print_manual打印用户帮助手册

     }

     else if(cmd_cnt==){//如果格式是"help [command]"

         print_cmdinfo(st);//打印单个命令的帮助信息

     }

 }

 void help(string str){

  if(str=="help"){

      cmd_cnt=;

      }

      else if(str.length()>){

       cmd_cnt=;

       st=str.substr(,str.length());

      }

      myhelp();

 }

 /////////////////////////////////////////////////////////////////////////////////

 int main()

 {

   string n;

   string str1; //first str !=include space

   string str2;

   while(true){

       printprompt();

       n=strInput();

     istringstream istr(n);

     istr >> str1>>str2;

     if(str1 == "ls"){

         ls(n,str1);

         continue;

     }

       if(n=="exit")//退出

           exit();

        else if(n=="clr"){

           myclr();

        }

        else if(n=="time")

        {

            mytime();

        }

        else if(n=="myshell")

        {

            welcome();

        }

        else if(n=="quit")

        {

        myquit();

        }

        else if(n=="pwd")

        {

        mypwd();

        }

     else if(str1 == "cat"){

       cat(str2);

     }

        else if(str1=="help"){

        help(n);

        }

     else

         cout << "invaild command" << endl;

   }

   return ;

 }