#include "stdio.h"
#include "malloc.h"

#define SIZE 3

#ifndef FALSE
    #define FALSE 0
#endif
#ifndef TRUE
    #define TRUE 1
#endif

#define NONE    0
#define PLAYER_A    1
#define PLAYER_B    2
#define WARNNING    255
#define COMPETITOR    200
#define WINNER    -1

char chessboard[SIZE][SIZE];

struct CHESS_MAN
{
    int row;
    int col;
};

/*get the value of current chess board:
    count and retrun how many ways the player can win the game*/
int get_value(int player)
{
    int i,j,ret=0;
    int row,col,inc;
    int bNONE=FALSE;

    /*check the row*/
    for(i=0;i<SIZE;i++)
    {
        row=SIZE;
        bNONE=FALSE;
        for(j=0;j<SIZE;j++)
        {
            /*if there is a competitor's chess man at the location
                sub row*/
            if(chessboard[i][j]==player)
                row--;
            /*if there is any empty location in the row,
                set bNONE as TRUE*/
            if(chessboard[i][j]==NONE)
                bNONE=TRUE;
        }
        /*computer :
            one empty and others are competitor's chess man,
            oh my god, danger, you may lose the game*/
        if(row==1&&bNONE==TRUE)
            return WARNNING;
        /*computer :
            no competitor's chess man in the row,
            there is one way to make me win the game*/
        else if(row==SIZE)
            ret++;
    }
    /*check the col*/
    for(i=0;i<SIZE;i++)
    {
        col=SIZE;
        bNONE=FALSE;
        for(j=0;j<SIZE;j++)
        {
            if(chessboard[j][i]==player)
                col--;
            if(chessboard[j][i]==NONE)
                bNONE=TRUE;
        }
        /*computer :
            warnning : the competitor may be win the game*/
        if(col==1&&bNONE==TRUE)
            return WARNNING;
        /*computer :
            this is my chance.*/
        else if(col==SIZE)
            ret++;
    }
    /*check inc*/
    inc=SIZE;
    bNONE=FALSE;
    for(i=0,j=0;i<SIZE;i++,j++)
    {
        if(chessboard[i][j]==player)
            inc--;
        if(chessboard[i][j]==NONE)
            bNONE=TRUE;
    }
    /*computer : i won't lose the game*/
    if(inc==1&&bNONE==TRUE)
        return WARNNING;
    /*my chance?*/
    else if(inc==SIZE)
        ret++;

    /*check inc*/
    inc=SIZE;
    bNONE=FALSE;
    for(i=0,j=SIZE-1;i<SIZE;i++,j--)
    {
        if(chessboard[i][j]==player)
            inc--;
        if(chessboard[i][j]==NONE)
            bNONE=TRUE;
    }
    /*be careful*/
    if(inc==1&&bNONE==TRUE)
        return WARNNING;
    /*another chance*/
    else if(inc==SIZE)
        ret++;

    return ret;
};

/*display the chess board*/
void disp_chess_board(void)
{
    int i,j;
    /*print the head*/
    for(i=0;i<SIZE*4+1;i++)
        printf("-");
    printf("\n");

    /*print the contect*/
    for(i=0;i<SIZE;i++)
    {
        printf("|");
        for(j=0;j<SIZE;j++)
        {
            if(chessboard[i][j]==PLAYER_A)
                printf(" o |");
            else if(chessboard[i][j]==PLAYER_B)
                printf(" x |");
            else
                printf("   |");
        }
        printf("\n");
        /*print the floor*/
        for(j=0;j<SIZE*4+1;j++)
            printf("-");
        printf("\n");
    }
    return;
};

/*init the chess board*/
void init_chess_board(void)
{
    int i,j;
    for(i=0;i<SIZE;i++)
        for(j=0;j<SIZE;j++)
            chessboard[i][j]=NONE;
    return;
};

int enter_chess_man(int row, int col, int player)
{
    /*out of size*/
    if(row>=SIZE||col>=SIZE)
        return FALSE;
    /*the pionted location is not empty*/
    if(chessboard[row][col]!=NONE)
        return FALSE;
    /*okay, put down the chess man*/
    chessboard[row][col]=player;
    return TRUE;
};

/*check whetch the player win the game*/
int chk_winner(int player)
{
    int i,j;
    int col,row,inc;

    /*are there all the player's chess men in the same row*/
    for(i=0;i<SIZE;i++)
    {
        row=TRUE;
        for(j=0;j<SIZE;j++)
        {
            if(chessboard[i][j]!=player)
                row=FALSE;
        }
        if(row==TRUE)
            return TRUE;
    }
    /*are there all the player's chess men in the same col*/
    for(i=0;i<SIZE;i++)
    {
        col=FALSE;
        for(j=0;j<SIZE;j++)
        {
            if(chessboard[j][i]!=player)
                col=FALSE;
        }
        if(col==TRUE)
            return TRUE;
    }
    /*what about the inc*/
    inc=TRUE;
    j=0;
    for(i=0;i<SIZE;i++)
        if(chessboard[i][i+j]!=player)
            inc=FALSE;
    if(inc==TRUE)
        return TRUE;
    /*and this?*/
    inc=TRUE;
    j=SIZE-1;
    for(i=0;i<SIZE;i++)
        if(chessboard[i][j-i]!=player)
            inc=FALSE;
    if(inc==TRUE)
        return TRUE;
    /*sorry, the player has not won yet.*/
    return FALSE;
};

/*get the best chess man for player*/
int get_best_chess(struct CHESS_MAN *best_chess, int player, int other)
{
    int tat_num=SIZE*SIZE;
    int chess_value[tat_num];
    struct CHESS_MAN chess[tat_num];
    int i,j,cur=0;

    /*init chess[]*/
    for(i=0;i<SIZE;i++)
    {
        for(j=0;j<SIZE;j++)
        {
            chess[cur].row=i;
            chess[cur++].col=j;
        }
    }

    /*when i take one of the chess man,
        what's the chess_value of my competitor
        i will choose the min value,
        because it means that's the worst case for him*/
    for(i=0;i<tat_num;i++)
    {
        /*i try to take this chess_man*/
        if(enter_chess_man(chess[i].row,chess[i].col,player)==TRUE)
        {
            chess_value[i]=get_value(other);
            /**/
            if(chk_winner(player)==TRUE)
                chess_value[i]=WINNER;
            chessboard[chess[i].row][chess[i].col]=NONE;
        }
        else
        /*can not take, means that
            chess_board has layed my cpmpetitor's chess_man*/
            chess_value[i]=COMPETITOR;
    }
    /*choose the lowest chess_value*/
    cur=0;
    for(i=0;i<tat_num;i++)
    {
        if(chess_value[cur]>chess_value[i])
            cur=i;
    }
    /*my best is my competitor's worst*/
    best_chess->row=chess[cur].row;
    best_chess->col=chess[cur].col;

    return chess_value[cur];
};

int chk_full(void)
{
    int i,j;
    for(i=0;i<SIZE;i++)
        for(j=0;j<SIZE;j++)
            if(chessboard[i][j]==NONE)
                return FALSE;
    return TRUE;
};

int main(void)
{
    int i;
    struct CHESS_MAN best_chess;
    int player=PLAYER_A;
    int competitor=PLAYER_B;
    int bEND=FALSE;    /*whetch need end of the program*/
    int row,col;    /*user's input location*/

    //best_chess=(struct CHESS_MAN*)malloc(sizeof(struct CHESS_MAN));
    init_chess_board();
    disp_chess_board();
   
    while(bEND==FALSE)
    {
        if(player==PLAYER_A)
        {
            /*user's turn*/
            do
            {
                printf("] Input your chess location : \n");
                printf("] location > row : ");
                scanf("%d",&row);
                printf("] location > col : ");
                scanf("%d",&col);
                if(enter_chess_man(row-1,col-1,player)==TRUE)
                {
                    printf("] You have take chess man at [%d][%d]\n",row,col);
                    break;
                }
                else
                    printf("] Error : You put the chess to a wrong location\n");
            }while(TRUE);
        }
        else
        {
            /*computer says : it is my turn.*/
            get_best_chess(&best_chess,player,competitor);
            enter_chess_man(best_chess.row,best_chess.col,player);
            printf("] Player %d put chess at [%d][%d]\n",player,best_chess.row+1,best_chess.col+1);
        }

        /*display the current chess board*/
        disp_chess_board();

        /*anybody win?!*/
        bEND=TRUE;
        if(chk_winner(player))
            printf("] Player %d Win the Game.\n",player);
        else if(chk_winner(competitor))
            printf("] Player %d Win the Game.\n",competitor);
        else if(chk_full())
            printf("] No One Win the Game.\n");
        else
            bEND=FALSE;

        /*change the turn of the players*/
        competitor=player;
        if(player==PLAYER_A)
            player=PLAYER_B;
        else
            player=PLAYER_A;
    };

    printf("\n\nthe command completed successfully.\n\n");
    return 0;
};