/* dining.c */

#include "asm.h"
#include "dining.h"
#include "scheduler.h"
#include "string.h"
#include "process.h"
#include "message.h"
#include "tty3.h"

void dining() {
  char args[2][MAX_STR_LEN];
  int waiter_pid = new_p("waiter", args);
  int i;
  for (i = 0; i < PHILS; i++) {
    int_to_string(args[0], waiter_pid);
    new_p("phil", args);
  }
  terminate(get_running() + 1);
}

void end_dinner(int waiter_pid, int eat_log[]) {
  int i;
  for (i = waiter_pid + 1; i < waiter_pid + PHILS; i++)
    { terminate(i); }
  for (i = 0; i < PHILS; i++) {
    print_int(i + 1);
    print_string(" ate ");
    print_int(eat_log[i]);
    print_string(" times.\n");
  }
  terminate(waiter_pid);
}

void waiter() {
  int food = 5;
  int id = get_running();
  int pid = id + 1;
  int free_forks[FORKS];
  int eat_log[PHILS];
  int i;
  for(i = 0; i < FORKS; i++) {
    free_forks[i] = 1;
    eat_log[i] = 0;
  }
  while(1) {
    if (receive_message()) {
      int from_pid = PCB_list[id].current_message.sender_pid;
      int left_fork = from_pid - pid - 1;
      int right_fork = left_fork - 1;
      if (right_fork == -1) { right_fork = FORKS - 1; }
      if (name_comp(PCB_list[id].current_message.data, "done")) {
        eat_log[from_pid - pid - 1]++;
        if (!(food--)) { end_dinner(pid, eat_log); }
        free_forks[left_fork] = 1;
        free_forks[right_fork] = 1;
      }
      else if (name_comp(PCB_list[id].current_message.data, "left")) {
        if (free_forks[left_fork] && check_forks(free_forks)) {
          free_forks[left_fork] = 0;
          send_message("Left fork", 1, from_pid);
        }
      }
      else if (name_comp(PCB_list[id].current_message.data, "right")) {
        if (free_forks[right_fork] && check_forks(free_forks)) {
          free_forks[right_fork] = 0;
          send_message("Right fork", 1, from_pid);
        }
      }
    }
  }
}

int check_forks(int forks[]) {
  int sum = 0;
  int i;
  for(i = 0; i < FORKS; i++) {
    if (forks[i]) { sum++; }
  }
  if (sum > 1) { return 1; }
  else { return 0; }
}

void phil() {
  int id = get_running();
  int pid = id + 1;
  int waiter_pid = string_to_int(PCB_list[id].arg_1);
  int phil_id = pid - waiter_pid;
  int state = THINK;
  while(1) {
    if (state == THINK) {
      hold_rand(pid);
      state = NO_FORK;
      print_int(phil_id);
      print_string(" wants to eat, but has no forks.\n");
    }
    if (state == NO_FORK) {
      send_message("left", 1, waiter_pid);
      while(!receive_message())
        ;
      print_int(phil_id);
      print_string(" wants to eat, but has only the left fork.\n");
      state = LEFT_FORK;
    }
    if (state == LEFT_FORK) {
      send_message("right", 1, waiter_pid);
      while(!receive_message())
        ;
      print_int(phil_id);
      print_string(" is eating.\n");
      state = EAT;
    }
    if (state == EAT) {
      hold_rand(pid);
      send_message("done", 1, waiter_pid);
      print_int(phil_id);
      print_string(" is thinking.\n");
      state = THINK;
    }
  }
}

void hold_rand(int pid) {
  int target = (int)get_timer() % 7;
  int its = 0;
  while(its++ < target) { hold(pid); }
}