/*
 * SList.cpp
 *
 *  Created on: Jun 16, 2018
 *      Author: OS1
 */
#include "PCB.h"
#include "SList.h"
#include "SCHEDULE.H"
//global list
SleepList* SleepList::sleepingList = NULL;

//constructor
SleepList::SleepList(){
	first = NULL;
	last = NULL;
}

//destructor
SleepList::~SleepList(){
	Node* currentNode = this->first; // initialize current node to first
	while (currentNode){

		Node* nextNode = currentNode->next;    // get next node
		delete currentNode;                         // delete current
		currentNode = nextNode;                     // set current to "old" next

	}
	this->first = NULL;
	this->last = NULL;
}


void SleepList::insertFirst(PCB *newPCB, int sleepTime){
	//error
	if(newPCB == NULL)
		return;

	//if there is no first node
	if(first == NULL){
		first = new Node(newPCB, sleepTime);
		last = first;
		return;
	}


	Node *temp = new Node(newPCB, sleepTime);
	//out of memory
	if(temp == NULL)
		return;

	temp->next = first;
	first = temp;

	return;

}
void SleepList::insertLast(PCB *newPCB, int sleepTime){
	//error
	if(newPCB == NULL)
		return;

	//if there is no last node
	if(last == NULL){
		last = new Node(newPCB, sleepTime);
		first = last;
		return;
	}

	Node* temp = new Node(newPCB, sleepTime);

	//out of memory
	if(temp == NULL)
		return;

	last->next = temp;
	last = temp;
}
void SleepList::insertSorted(PCB *newPCB, int sleepTime){
	//error
	if(newPCB == NULL)
		return;
	//empty list case
	if(first == NULL){
		first = new Node(newPCB, sleepTime);
		last = first;
		return;
	}

	//first edge case
	if(sleepTime <= first->sleepTime){
		insertFirst(newPCB, sleepTime);
		return;
	}

	//second edge case
	if(sleepTime >= last->sleepTime){
		insertLast(newPCB, sleepTime);
		return;
	}

	//'mid' case
	Node *curr, *prev;
	curr = first;
	prev = NULL;

	while(curr != NULL && curr->sleepTime <= sleepTime){
		prev = curr;
		curr = curr->next;
	}

	//some error occured
	if(curr == NULL || prev == NULL){
		return;
	}


	//now curr points to the first node with a greater sleep time
	Node *temp = new Node(newPCB, sleepTime);
	prev->next = temp;
	temp->next = curr;

}

void SleepList::decrementAll(){

	if(first == NULL){
		return;
	}

	Node *temp = first;

	while(temp != NULL){

		temp->sleepTime -= 1;
		temp = temp->next;
	}

}

void SleepList::simulateSleep() {

	//there are no threads asleep
	if (first == NULL)
		return;


	//we are reducing remaining times to all the sleeping threads
	decrementAll();

	while (first != 0 && first->sleepTime == 0) {

		//we are removing the first element from the list
		Node *temp = first;
		first = first->next;

		//we are taking the PCB and puttiing it in the scheduler
		PCB* wakeUp = temp->pcb;
		wakeUp->state = READY;
		Scheduler::put(wakeUp);

		delete temp;

	}

	//if the list is empty restart the pointers
	if(first == NULL){
		last = NULL;
	}

}