#include <stdlib.h>
#include "queue.h"

void enqueue(queue_t *q, local_id id, timestamp_t time) {
  if( q == NULL )
    return;

	node_t *node = (node_t *) malloc(sizeof(*node));
	node->id   = id; 
	node->time = time; 
	node->next = NULL;

	if(q->front == NULL && q->rear == NULL){
		q->front = q->rear = node;
		return;
	}
  
  node_t *current = q->front;
  node_t *previous = NULL;

  while(current != NULL) {
    if( current->time > time || 
      ( current->time == time && id < current->id ) ) {

      node->next = current;
      if( previous )
        previous->next = node;

      if( current == q->front )
        q->front = node;

      node = NULL;
      break;
    } else {
      previous = current;
      current = current->next;
    }
  }

  if( node ) {
    q->rear->next = node;
    q->rear = node;
    node = NULL;
  }
}

void dequeue(queue_t *q) {
	struct Node* temp = q->front;
	if(q->front == NULL)
		return;

	if(q->front == q->rear)
		q->front = q->rear = NULL;
	else
		q->front = q->front->next;

	free(temp);
}

node_t *front(queue_t *q) {
  if( q == NULL )
    return NULL;

  return q->front;
}

queue_t *queue() {
	queue_t *q = (queue_t*) malloc(sizeof(*q));
  if( q == NULL )
    return NULL;

  q->front = NULL;
  q->rear  = NULL;
  return q;
}

void free_queue(queue_t *q) {
  if( q == NULL )
    return;

  struct Node* temp = q->front;
  while(temp != NULL) {
    temp = temp->next;
    free(temp);
  }
  free(q);
}