/*
 * Deque Work stealing problem for CSC 3102 Portfolio
*/

/*
 * --REQUIRED METHODS--
 * Store(int numLines, int numCustomers)
 * Customer()
 * Line()
 * Enq_back()
 * Deq_back()
 * Deq_front()
 * 
 * --I IMPLEMENTED--
 * Restructure() -> makes sure no line has >2 customer in it
 * TimeSlice() -> Each customer at front of their line scans one item
 * PrintStore() -> prints each line and the number of items each customer has
*/



using DequeWSProblem_3102;


namespace DequeWSProblem_3102
{
    public class Customer
    {
        public int items;
        public Customer? next, prev;

        public Customer()
        {
            items = new Random().Next(5, 26);
            next = null;
            prev = null;
        }
    }

    public class Line 
    {
        public Customer? front, back;
        public Line? nextLine, prevLine; 
        public int sizeOfLine;

        public Line()
        {
            sizeOfLine = 0;
            front = null;
            back = null;
        }

        /*
         * Adds a customer to the back of the specified line
         * This is used in the Store.Enq_Back() function
        */
        public void Enque_Back()
        {
            if (front == null)
            {
                Customer newCustomer = new Customer();
                front = newCustomer;
                back = newCustomer;
            }
            else
            {
                Customer newCustomer = new Customer();
                newCustomer.next = back;
                back.prev = newCustomer;
                back = newCustomer;
            }
            sizeOfLine++;
        }

        /*
         * Removes a customer from the back of the specified line
         * This is used in the Store.Deq_Back() function
        */
        public void Deque_Back()
        {
            if (front == null)
            {
                return;
            }
            else if (sizeOfLine == 1)
            {
                front = null;
                back = null;
                sizeOfLine = 0;
            }
            else
            {
                back = back.next;
                back.prev.next = null;
                back.prev = null;
                sizeOfLine--;
            }
        }

        /*
         * Dequeues the customer at the front of the specified line
        */
        public void Dequeue_Front()
        {
            if (front == null)
            {
                return;
            }
            else if (sizeOfLine == 1)
            {
                front = null;
                back = null;
                sizeOfLine = 0;
            }
            else
            {
                front = front.prev;
                front.next.prev = null;
                front.next = null;
                sizeOfLine--;
            }
        }
    }

    public class Store 
    {

        public Line? firstLine, lastLine;
        public int numLines, numCustomers;

        /*
         * default constructor for the store class
         * @numlines - the number of lines you want the store to have
         * @numCustomers - the number of customers in the store at time of creation
        */
        

        public Store(int numLines, int numCustomers)
        {
            this.numLines = numLines;
            this.numCustomers = numCustomers;


            for (int i = 0; i < numLines; i++)
            {
                Line line = new Line();
                if (i == 0)
                {
                    firstLine = line;
                    lastLine = line;
                }
                else
                {
                    line.prevLine = lastLine;
                    lastLine.nextLine = line;
                    lastLine = line;
                }
            }

            for (int i = 0; i < numCustomers; i++)
            {
                int whichLine = new Random().Next(numLines);
                var tempLine = firstLine;
                for (int j = 0; j < whichLine; j++)
                {

                    tempLine = tempLine.nextLine;
                }
                tempLine.Enque_Back();           
            }
            this.Restructure();
        }

        /*
         * Adds a customer to the back of a random line in the store
        */
        public void Enq_Back()
        {
            int whichLine = new Random().Next(numLines);
            var tempLine = firstLine;
            for (int i = 0; i < whichLine; i++)
            {
                tempLine = tempLine.nextLine;
            }
            tempLine.Enque_Back();
            numCustomers++;
            this.Restructure();
        }

        /*
         * Removes a customer from the back of a random line in the store
        */
        public void Deq_Back()
        {
            int whichLine = new Random().Next(numLines);
            var tempLine = firstLine;
            for (int i = 0; i < whichLine; i++)
            {
                tempLine = tempLine.nextLine;
            }
            tempLine.Deque_Back();
            numCustomers--;
            this.Restructure();
        }

        /*
         * Removes the customer at the beginning of a random line
        */
        public void Deq_Front()
        {
            int whichLine = new Random().Next(numLines);
            var tempLine = firstLine;
            for (int i = 0; i < whichLine; i++)
            {
                tempLine = tempLine.nextLine;
            }
            tempLine.Dequeue_Front();
            numCustomers--;
            this.Restructure();
        }

        /*
         * Checks if a line in the store is empty, if so, takes from a line that has >2 customers in it
        */

        public void Restructure()
        {
            var tempLine = firstLine;
            for (int i = 0; i < numLines; i++) //looks through every line to see if there is one that is empty
            {
                if(tempLine.sizeOfLine != 0)
                {
                    tempLine = tempLine.nextLine;
                }
                else //finds a line that is empty
                {
                    var checkLine = firstLine;
                    for (int j = 0; j < numLines; j++) //looks to see if there is a line with >=2 customers than tempLine
                    {
                        if (checkLine.sizeOfLine >= (tempLine.sizeOfLine + 2)) //finds line with >=2 customers than tempLine
                        {
                            while (checkLine.sizeOfLine >= tempLine.sizeOfLine + 2)
                            {
                                if (tempLine.sizeOfLine == 0)
                                {
                                    tempLine.front = checkLine.back;
                                    tempLine.back = tempLine.front;
                                    checkLine.back = checkLine.back.next;
                                    checkLine.back.prev = null;
                                    tempLine.front.next = null;
                                    checkLine.sizeOfLine--;
                                    tempLine.sizeOfLine++;
                                }
                                else
                                {
                                    tempLine.back = checkLine.back;
                                    checkLine.back = checkLine.back.next;
                                    checkLine.back.prev = null;
                                    var tmp = tempLine.front;
                                    while (tmp.prev != null) //tmp will be the last node in the temp Line
                                    {
                                        tmp = tmp.prev;
                                    }
                                    tmp.prev = tempLine.back;
                                    tempLine.back.next = tmp;
                                    checkLine.sizeOfLine--;
                                    tempLine.sizeOfLine++;
                                }
                            }
                            break; //breaks from the for loop that found the empty line
                        }
                        else
                        {
                            checkLine = checkLine.nextLine;
                        }
                    }
                }
            }
        }


        /*
         * prints each each line, and the amount of customers each have in the line
        */

        public void PrintStore()
        {
            var tempLine = firstLine;
            for (int i = 0; i < numLines; i++)
            {
                Console.WriteLine("Line #" + (i + 1));
                var tempCustomer = tempLine.front;
                for (int j = 0; j < tempLine.sizeOfLine; j++)
                {
                    Console.Write(tempCustomer.items + " ");
                    tempCustomer = tempCustomer.prev;
                }
                Console.WriteLine();
                tempLine = tempLine.nextLine;
            }
            Console.WriteLine();
        }

        /*
         * Passes one unit of time in our store, so each line will scan one item
        */
        public void TimeSlice()
        {
            var tempLine = firstLine;
            for (int i = 0; i < numLines; i++)
            {
                if (tempLine.front == null) //shouldn't happen unless store is empty, or very few people are in the store
                {
                    Restructure();
                    tempLine = tempLine.nextLine;
                }
                else
                {
                    if (tempLine.front.items == 0) //shouldn't happen, but handles case where customer has no items
                    {
                        tempLine.Dequeue_Front();
                        tempLine = tempLine.nextLine;
                    }
                    else
                    {
                        tempLine.front.items--;
                        if (tempLine.front.items == 0)
                        {
                            tempLine.Dequeue_Front();
                        }
                        tempLine = tempLine.nextLine;
                    }
                }                              
            }      
        }    
    }
}