#include <stdio.h>
#include <time.h>
#include "vds.h"
#include "comm.h"
#include "queue.c"
#include <stdlib.h>
#include <unistd.h>

#define MEALS 10
#define EATING 0
#define THINKING 1
#define HUNGRY 2
#define THINK_TIME 4
#define EAT_TIME 4
#define N_PHIL 5

int chopstick[5] = {1,1,1,1,1};
int mutex = 1;
Queue block_mutex;
Queue block_chopstick[5];

void test();
void Philo();
void think(int ph_id);
void eat(int ph_id,int meal);
void put_forks(int ph_id);
void get_forks(int ph_id);
int Request(int chopstick,int philosopher);
void Release (int chopstick,int philosopher);
void sem_wait(int chopstick_num, char* type);
void sem_signal(int chopstick_num, char* type);


int main(argc, argv)
int argc;
char *argv[];
{
	int  sid;


	/*
	 * 
	 * Site Initialization
	 *
	 *
	 */
	setbuf( stdout, NULL ); /* no output buffering */

	if (argc != 4) {
		fprintf(stderr, "Usage: %s <SID> <NS HOST> <NS PORT>\n", argv[0]);
		exit(ERROR);
	}

	if (SiteSetup(atoi(argv[1]), argv[2], atoi(argv[3])) == ERROR) {
		fprintf(stderr, "SiteInit(%d) failed.\n", atoi(argv[1]));
		exit(ERROR);
	}

	printf("I am site %d. I am up and running\n", atoi(argv[1]));


	Philo();	/* This is a simple test routine. You should comment it out */

	/*
	 *
	 * Lab 2 Protocol
	 *
	 * Philo_Init()
	 * while ( 1 ) {	
	 *   Philosophers simulation code
	 *
 	 * }
	 *
	 */



        /*
         * 
         * Site Termination
         *
         *
         */
	SiteExit();
}


void Philo()
{
     char *MSG = (char *)malloc(MAX_MSG_LEN);
     int i, sender;
     char delims[] = " ";   
     char *result = NULL;   
      
     block_mutex = CreateQueue(5);
     
     for(i=0;i<5;i++)
        block_chopstick[i] = CreateQueue(2);
     
     srand(MySID);
     if(MySID>=1 && MySID<=5)
     {
       while(1)
       {
	      for (i=0;i<MEALS;i++)
	      {
	        think(MySID);
	        get_forks(MySID);
	        eat(MySID,i);
	        put_forks(MySID);
	      }
	      printf("Philosopher %d's thread has exited\n",MySID);
        }    
     }
     else
     if(MySID == 6)  //if I am the site responsable for synchronization
     {
       //Do the work for the semaphores, increments and decrements 
       Receive(MSG, &sender);
       result = strtok( MSG, delims );
       if(strcmp(result,"Wait")==0)  //check if the message received corresponds to a sem_wait
       {
         result = strtok( NULL, delims ); 
         if(strcmp(result,"chopstick")==0) //check if the semaphore needed to be handled is "chopstick"
         {
             result = strtok( NULL, delims );
             for(i=0;i<5;i++)
             {
                 if(i == atoi(result))
                 {
                  chopstick[i]--;
                  if(chopstick[i]<0)
                    Enqueue(sender,block_chopstick[i]);//BLOCK the philosopher, put on waiting queue of this chopstick
                  else
                      Send("OK", sender);
                  }
             }
         }
         else
         if(strcmp(result,"mutex")==0) //check if the semaphore needed to be handled is "mutex"
         {
                  mutex--;
                  if(mutex<0)
                    Enqueue(sender,block_mutex);//BLOCK the philosopher, put on waiting queue -> mutex[sender]=0
                  else
                      Send("OK", sender); 
         }
       } //end of sew-wait handling
       else  
       if(strcmp(result,"Signal")==0)  //check if the message received corresponds to a sem_signal
       {
         result = strtok( NULL, delims ); 
         if(strcmp(result,"chopstick")==0) //check if the semaphore needed to be handled is "chopstick"
         {
             result = strtok( NULL, delims );
             for(i=0;i<5;i++)
             {
                 if(i == atoi(result))
                 {
                  chopstick[i]++;
                  if(chopstick[i]<=0)
                    Dequeue(block_chopstick[i]);//NBLOCK philosopher waiting on this chopstick from the blocking queue of this chopstick
                  Send("OK", sender);
                  }
             }
         }
         else
         if(strcmp(result,"mutex")==0) //check if the semaphore needed to be handled is "mutex"
         {
                  mutex++;
                  if(mutex<=0)
                    Dequeue(block_mutex);//NBLOCK philosopher waiting on mutex from the blocking queue of mutex
                  Send("OK", sender); 
         }
       }  //end of sem_signal handling           
    
     
    }//end of job for site responsable for synchronization 
    
} 
 
 
 
int Request(int chopstick,int philosopher)
{
	return 1;
}

void Release (int chopstick,int philosopher)
{
}
 
void sem_wait(int chopstick_num, char* type)
{
     char *MSG = (char *)malloc(MAX_MSG_LEN);
     char* string;
     int i,sender=6;
     if (strcmp(type,"chopstick")==0) //if dealing with semaphore "chopstick"
     {
          for(i=0;i<N_PHIL;i++)
          {
             if(i==chopstick_num)
             {
                sprintf(string, "Wait %s %d", type, i);
                Send(string, 6);
             }
          }
     }
     else
     if(strcmp(type,"mutex")==0)  //if dealing with semaphore mutex
     {
                sprintf(string, "Wait mutex");   
                Send(string, 6);
     }  
     Receive(MSG, &sender);
}


void sem_signal(int chopstick_num, char* type)
{
     char *MSG = (char *)malloc(MAX_MSG_LEN);
     char* string;
     int i,sender=6;
     if (strcmp(type,"chopstick")==0) //if dealing with semaphore "chopstick"
     {
          for(i=0;i<N_PHIL;i++)
          {
             if(i==chopstick_num)
             {
                sprintf(string, "Signal %s %d", type, i);
                Send(string, 6);
             }
          }
     }
     else
     if(strcmp(type,"mutex")==0)  //if dealing with semaphore mutex
     {
                sprintf(string, "Signal mutex");   
                Send(string, 6);
     }  
     Receive(MSG, &sender);
}


      
void think(int ph_id)
{
   int wait_time;
   wait_time=rand()%THINK_TIME+1;
   printf("\tPhilosopher %d is thinking for %d seconds.\n",ph_id,wait_time);
   sleep(wait_time);
}


void get_forks(int ph_id)
{
   int left=0,right=0;
   while(!left){
   	sem_wait(-1,"mutex");
	left=Request(ph_id-1,ph_id);
	sem_signal(-1,"mutex");
	if (!left)
	   sleep(1);
   }
   sem_wait(ph_id-1,"chopstick");
   while(!right){
        sem_wait(-1,"mutex");
	right=Request((ph_id)%N_PHIL,ph_id);
	sem_signal(-1,"mutex");
	if (!right)
	{
	   sleep(1);
	}
   }
   sem_wait((ph_id)%N_PHIL,"chopstick");
}


void eat(int ph_id,int meal)
{
   int wait_time;
   wait_time=rand()%EAT_TIME+1;
   printf("\tPhilosopher %d is eating meal %d for %d seconds.\n",ph_id,meal+1,wait_time);
   sleep(wait_time);
}


void put_forks(int ph_id)
{
   int i;
   sem_wait(-1,"mutex");
   Release(ph_id-1,ph_id);
   Release((ph_id)%N_PHIL,ph_id);
   sem_signal(ph_id-1,"chopstick");
   sem_signal((ph_id)%N_PHIL,"chopstick");
   sem_signal(-1,"mutex");
}



void test()
{
	/*
	 * To test: read, understand, then issue the command: 
 	 * vds <filename>, where <filename> is in local dir and 
	 * contains:
	 * 
	 * ------ start file
	 * 3
	 * 1 sand
	 * 2 sand
	 * 3 sand
	 * <your vds bin path>
	 * ------ end file
	 *
	 */

    char *MSG = (char *)malloc(MAX_MSG_LEN);
	int sender;

	sleep(3);
	if (MySID==3)  {
		sleep(3); 
		Send("Hi, I am 3 sending you my greetings\n\0", 2);
	}
	else if (MySID==2) {
		Send("Hi, I am 2 sending you my greetings\n\0", 3);
	}

	if(MySID==3 || MySID==2) {
		Receive(MSG, &sender);
		printf("Site %d: Received this msg fm site %d: %s\n", MySID, sender, MSG);
	}
	
}