#define _XOPEN_SOURCE 500

#include <cs50.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

// constants
#define DIM_MIN 3
#define DIM_MAX 9

// board
int board[DIM_MAX][DIM_MAX];

// dimensions
int d;


// prototypes
void clear(void);
void greet(void);
void init(void);
void draw(void);
bool move(int tile);
bool won(void);

int main(int argc, string argv[])
{

    // ensure proper usage
    if (argc != 2)
    {
        printf("Usage: fifteen d\n");
        return 1;
    }

    // ensure valid dimensions
    d = atoi(argv[1]);
    if (d < DIM_MIN || d > DIM_MAX)
    {
        printf("Board must be between %i x %i and %i x %i, inclusive.\n",
            DIM_MIN, DIM_MIN, DIM_MAX, DIM_MAX);
        return 2;
    }

    // open log
    FILE* file = fopen("log.txt", "w");
    if (file == NULL)
    {
        return 3;
    }

    // greet user with instructions
    greet();

    // initialize the board
    init();

    // accept moves until game is won
    while (true)
    {
        // clear the screen
        clear();

        // draw the current state of the board
        draw();

        // log the current state of the board (for testing)
        for (int i = 0; i < d; i++)
        {
            for (int j = 0; j < d; j++)
            {
                fprintf(file, "%i", board[i][j]);
                if (j < d - 1)
                {
                    fprintf(file, "|");
                }
            }
            fprintf(file, "\n");
        }
        fflush(file);

        // check for win
        if (won())
        {
            printf("ftw!\n");
            break;
        }

        // prompt for move
        printf("\nTile to move: ");
        int tile = GetInt();

        // quit if user inputs 0 (for testing)
        if (tile == 0)
        {
            break;
        }

        // log move (for testing)
        fprintf(file, "%i\n", tile);
        fflush(file);

        // move if possible, else report illegality
        if (!move(tile))
        {
            printf("\nIllegal move.\n");
            usleep(500000);
        }

        // sleep thread for animation's sake
        usleep(500000);
    }

    // close log
    fclose(file);

    // success
    return 0;
}

/**
 * Clears screen using ANSI escape sequences.
 */
void clear(void)
{
   printf("\033[2J");
   printf("\033[%d;%dH", 0, 0);
}

/**
 * Greets player.
 */
void greet(void)
{
    clear();
    printf("WELCOME TO GAME OF FIFTEEN\n");
    usleep(2000000);
}

/**
 * Initializes the game's board with tiles numbered 1 through d*d - 1
 * (i.e., fills 2D array with values but does not actually print them).
 */

void init(void)
{
    int count = 1;
    // TODO
    // init rows
    for (int row = 0; row < d; row++){
    // init columns
        for (int col = 0; col < d; col++){
            board [row][col] = (d*d) - count;
            count ++;

            if (d % 2 == 0){
            board[d-1][d-2] = 2;
            board[d-1][d-3] = 1;
            }
        }

      }

}

/**
 * Prints the board in its current state.
 */
void draw(void)
{
    // TODO
    for (int row =0; row < d; row++){
        for (int col = 0; col < d; col++){
            if (board[row][col] == 0){
                printf("%2s ", "_");
            }
            else {
            printf("%2d ", board[row][col]);
        }
        }
        printf("\n");
            }
        }


/**
 * If tile borders empty space, moves tile and returns true, else
 * returns false.
 */

bool move(int tile)
{
    int temp;

    int blankrow;
    int blankcol;

    int tilerow;
    int tilecol;

    for (int row = 0; row < d; row++){
        for (int col = 0; col < d; col++){

            // find zero tile position
            if (board[row][col] == 0){
                blankrow = row;
                blankcol = col;
                }


            // find target tile position
                if (board[row][col] == tile) {
                tilerow = row;
                tilecol = col;
                }
        }
    }


                // determine if move is legal
                if (((tilecol == blankcol) && (tilerow == blankrow +1 || tilerow == blankrow -1)) || ((tilerow == blankrow) && (tilecol == blankcol + 1 || tilecol == blankcol - 1))){
                // legal move is permitted...blankrow and col must be updated once swap takes places
                temp = board[blankrow][blankcol];
                board[blankrow][blankcol] = tile;
                tile = temp;
                board[tilerow][tilecol] = 0;
                return true;

                }

                else{
                    return false;
                }



        return true;
    }



/**
 * Returns true if game is won (i.e., board is in winning configuration),
 * else false.
 */

bool won(void)
{
    for (int row = 0; row < d-1; row++){
        for (int col = 0; col < d-1; col++){
            if (board[row][col] == 0){
                if(board[row][col]++){
                return true;
            }
            else{
                return false;
            }
            }
        }
    }
    return true;
}