using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _8_puzzle
{

    class Solution
    {
        public int[] puzzle = new int[] { 1, 2, 3,
                                   0, 4, 6,
                                   7,5, 8 };
        int[] goalPuzzle = new int[] { 1, 2, 3,
                                         4, 5, 6,
                                         7,8, 0 };
        int[] leftMovedPuzzle = new int[] { 0, 0, 0, 0, 0, 0, 0, 0, 0 };
        int[] rightMovedPuzzle = new int[] { 0, 0, 0, 0, 0, 0, 0, 0, 0 };
        int[] upMovedPuzzle = new int[] { 0, 0, 0, 0, 0, 0, 0, 0, 0 };
        int[] downtMovedPuzzle = new int[] { 0, 0, 0, 0, 0, 0, 0, 0, 0 };
        public bool puzzleIsNotSolved = true;
        int blankPosition = 0, manHattanCost = 0, leftMovCost = 0, rightMovCost = 0, upMovCost = 0, downMovCost = 0;
        bool upMove = true, leftMove = true, rightMove = true, downMove = true;
        private int reversalMov = 0, level = 0;
        //public Timer timer1 = new System.Windows.Forms.Timer();

        public Solution()
        {
            int i = 0;
            while (i < 9)
            {
                Console.Write(puzzle[i]);
                Console.Write("  ");
                if (i == 2 || i == 5 || i == 8) Console.WriteLine();
                i++;
            }
            Console.WriteLine();


            while (puzzleIsNotSolved)
            {
                checkPuzzle();
                if (puzzleIsNotSolved) checkMove();
                i = 0;
                while (i < 9)
                {
                    Console.Write(puzzle[i]);
                    Console.Write("  ");
                    if (i == 2 || i == 5 || i == 8) Console.WriteLine();
                    i++;
                }
                Console.WriteLine();



            }


            Console.ReadKey();
        }



        private void checkPuzzle()
        {

            if (goalPuzzle.SequenceEqual(puzzle))
            {
                puzzleIsNotSolved = false;
                Console.Write("Solved  ");
                Console.WriteLine();
            }

        }

        void checkMove()
        {
            //level++;
            int i = 0;
            while (i < 9)
            {
                if (puzzle[i] == 0)
                {
                    blankPosition = i;
                    break;
                }
                i++;
            }
            if (blankPosition <= 2)
            {
                upMove = false;
                upMovCost = 100;
            }
            else if (blankPosition > 5)
            {
                downMove = false;
                downMovCost = 100;
            }
            if (blankPosition % 3 == 0)
            {
                leftMove = false;
                leftMovCost = 100;
            }
            else if ((blankPosition + 1) % 3 == 0)
            {
                rightMove = false;
                rightMovCost = 100;
            }
            if (upMove) { Console.Write("Manhattan cost for Up Move: "); moveToUp(); }
            if (downMove) { Console.Write("Manhattan cost for Down Move: "); moveToDown(); }

            if (leftMove) { Console.Write("Manhattan cost for Left Move: "); moveToLeft(); }

            if (rightMove) { Console.Write("Manhattan cost for Right Move: "); moveToRight(); }



            if (upMovCost <= downMovCost && upMovCost <= leftMovCost && upMovCost <= rightMovCost)
            {
                puzzle = swapPuzzle(upMovedPuzzle);
                Console.WriteLine();
                Console.WriteLine("Up Move: ");
                Console.WriteLine();
            }
            if (downMovCost <= upMovCost && downMovCost <= leftMovCost && downMovCost <= rightMovCost)
            {
                puzzle = swapPuzzle(downtMovedPuzzle);
                Console.WriteLine();
                Console.WriteLine("Down Move: ");
                Console.WriteLine();
            }
            if (leftMovCost <= upMovCost && leftMovCost <= downMovCost && leftMovCost <= rightMovCost)
            {
                puzzle = swapPuzzle(leftMovedPuzzle);
                Console.WriteLine();
                Console.WriteLine("Left Move: ");
                Console.WriteLine();
            }
            if (rightMovCost <= upMovCost && rightMovCost <= leftMovCost && rightMovCost <= downMovCost)
            {
                puzzle = swapPuzzle(rightMovedPuzzle);
                Console.WriteLine();
                Console.WriteLine("Right Move: ");
                Console.WriteLine();
            }

            upMove = true; leftMove = true; rightMove = true; downMove = true;
            blankPosition = 0; leftMovCost = 0; rightMovCost = 0; upMovCost = 0; downMovCost = 0;

        }
        void moveToUp()
        {
            upMovedPuzzle = swapPuzzle(puzzle);
            upMovedPuzzle[blankPosition] = puzzle[blankPosition - 3];
            upMovedPuzzle[blankPosition - 3] = puzzle[blankPosition];
            upMovCost = puzzleSolvingCost(upMovedPuzzle);
        }
        void moveToDown()
        {
            downtMovedPuzzle = swapPuzzle(puzzle);
            downtMovedPuzzle[blankPosition] = puzzle[blankPosition + 3];
            downtMovedPuzzle[blankPosition + 3] = puzzle[blankPosition];
            downMovCost = puzzleSolvingCost(downtMovedPuzzle);
        }
        void moveToLeft()
        {
            leftMovedPuzzle = swapPuzzle(puzzle);
            leftMovedPuzzle[blankPosition] = puzzle[blankPosition - 1];
            leftMovedPuzzle[blankPosition - 1] = puzzle[blankPosition];
            leftMovCost = puzzleSolvingCost(leftMovedPuzzle);
        }
        void moveToRight()
        {
            rightMovedPuzzle = swapPuzzle(puzzle);
            rightMovedPuzzle[blankPosition] = puzzle[blankPosition + 1];
            //Console.WriteLine(blankPosition);
            rightMovedPuzzle[blankPosition + 1] = puzzle[blankPosition];
            rightMovCost = puzzleSolvingCost(rightMovedPuzzle);
        }
        int puzzleSolvingCost(int[] temp)
        {
            int i = 0;
            manHattanCost = 0;
            while (i < 9)
            {
                if (temp[i] != goalPuzzle[i])
                {
                    if (temp[i] != 0)
                    {
                        manHattanCost += Math.Abs((i - (temp[i] - 1)));

                    }
                    else
                    {
                        manHattanCost += Math.Abs(8 - i);
                    }


                }
                //if (temp[i] != goalPuzzle[i])
                //{
                //    misMathccost++;
                //}
                //if (i < 8)
                //{
                //    if (temp[i] == goalPuzzle[i + 1] && temp[i + 1] == goalPuzzle[i])
                //    {
                //        reversalMov++;
                //    }

                //}
                i++;
            }
            //return (level+ misMathccost + reversalMov);
            Console.WriteLine(manHattanCost);
            return manHattanCost;
        }
        int[] swapPuzzle(int[] temp)
        {
            int[] swappedPuzzle = new int[] { 0, 0, 0, 0, 0, 0, 0, 0, 0 };
            int i = 0;
            while (i < 9)
            {

                swappedPuzzle[i] = temp[i];
                i++;
            }
            return swappedPuzzle;
        }

    }


}