/* 
 _  
|_)
| \EVERSI


Authored by abakh <abakh@tuta.io>
To the extent possible under law, the author(s) have dedicated all copyright and related and neighboring rights to this software to the public domain worldwide. This software is distributed without any warranty.

You should have received a copy of the CC0 Public Domain Dedication along with this software. If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.


*/
#include <curses.h>
#include <string.h>
#include <stdlib.h>
#include <signal.h>
#include <stdbool.h>
typedef signed char byte;

byte py,px;//cursor
const char piece[2] = {'O','X'};
char game[8][8];//main board
byte computer[2] = {0,0};
byte score[2];//set by header()

void rectangle(byte sy,byte sx){
	for(byte y=0;y<=8+1;++y){
		mvaddch(sy+y,sx,ACS_VLINE);
		mvaddch(sy+y,sx+8*2,ACS_VLINE);
	}
	for(byte x=0;x<=8*2;++x){
		mvaddch(sy,sx+x,ACS_HLINE);
		mvaddch(sy+8+1,sx+x,ACS_HLINE);
	}
	mvaddch(sy,sx,ACS_ULCORNER);
	mvaddch(sy+8+1,sx,ACS_LLCORNER);
	mvaddch(sy,sx+8*2,ACS_URCORNER);
	mvaddch(sy+8+1,sx+8*2,ACS_LRCORNER);
}

void header(void){//abuse, used to count the pieces on each side too
	score[0]=score[1]=0;
	for(byte y=0;y<8;++y){
		for(byte x=0;x<8;++x){
			if(game[y][x]){
				if(game[y][x]==piece[0])
					score[0]++;
				else
					score[1]++;
			}
		}
	}
	mvaddch(0,1,  '_');
	mvprintw(1,0,"|_) %2d:%2d",score[0],score[1]);
	mvprintw(2,0,"| \\EVERSI ");
}

void draw(byte sy,byte sx){//the game's board 
	rectangle(sy,sx);
	chtype attr ;
	for(byte y=0;y<8;++y){
		for(byte x=0;x<8;++x){
			attr=A_NORMAL;
			if(y==py && x==px)
				attr |= A_STANDOUT;
			if(game[y][x])
				mvaddch(sy+1+y,sx+x*2+1,attr|game[y][x]);
			else				
				mvaddch(sy+1+y,sx+x*2+1,attr|'.');
		}
	}
}

bool can_reverse(byte ty , byte tx,char board[8][8],char piece){//can place a piece there?
	byte y,x,count;
	if(board[ty][tx])
		return false;
	for(byte dy=-1;dy<2;++dy){ //changes the direction
		for(byte dx=-1;dx<2;++dx){
			if(dx==0&&dy==0)//it would be itself
				dx=1;
			count=0;
			y=ty+dy;
			x=tx+dx;
			while(1){
				if(y<0 || y>=8 ||x<0 || x>=8){//reaches edges of the board
					count=0;
					break;
				}
				if(!board[y][x]){//gap
					count=0;
					break;
				}

				if(board[y][x]!=piece){
					++count;
					y+=dy;
					x+=dx;
				}
				else
					break;//same color
			}
			if(count)
				return true;
		}
	}
	return false;
}

void reverse(byte ty,byte tx,char board[8][8],char piece){//place a piece there
	board[ty][tx]=piece;
	byte y,x;
	for(byte dy=-1;dy<2;++dy){//changes the direction
		for(byte dx=-1;dx<2;++dx){
			if(dy==0 && dx==0)
				dx=1;
			y=ty+dy;
			x=tx+dx;
			while(1){
				if(y<0 || y>=8 || x<0 || x>=8)
					break;
				if(!board[y][x])
					break;
				if(board[y][x]!=piece){
					y+=dy;
					x+=dx;
				}
				else{ //of same kind
					while(y!=ty || x!=tx){ //reverse the disks
						board[y][x]=piece;
						y-=dy;
						x-=dx;
					}
					break;
				}
			}
		}
	}
}

bool can_move(char board[8][8],char piece){//can move at all?
	for(byte y=0;y<8;++y)
		for(byte x=0;x<8;++x)
			if(can_reverse(y,x,board,piece))
				return true;
	return false;
}

double advantage(char board[8][8],char piece){
	double own=0;
	double opp=0;
	for(byte y=0;y<8;++y){
		for(byte x=0;x<8;++x){
			if(board[y][x]){
				if(board[y][x]==piece){
					++own;
					if( ((y==7 || y==0)&&(x!=7 && x!=0)) || ((x==7 || x==0)&&(y!=7 && y!=0)) )//edges
						own+=100;
					if( (y==7 || y==0)&&(x==7 || x==0) )//corners
						own+=10000;
				}
				else{
					++opp;
					if( ((y==7 || y==0)&&(x!=7 && x!=0)) || ((x==7 || x==0)&&(y!=7 && y!=0)) )
						opp+=100;
					if( (y==7 || y==0)&&(x==7 || x==0) )
						opp+=10000;
				}
			}
			
		}
	}
	return own/opp;
}

void cp(char A[8][8],char B[8][8]){//copy the board A to B
	for(byte y=0;y<8;++y)
		for(byte x=0;x<8;++x)
			B[y][x]=A[y][x];
}

double decide(char board[8][8],char piece,char opponet,byte depth){//AI algorithm
	if(!can_move(board,piece))
		return 0;
	char plan[8][8];
	double adv,bestadv;
	adv=bestadv=0;
	byte besty,bestx;
	for(byte y=0;y<8;++y){
		for(byte x=0;x<8;++x){
			if(can_reverse(y,x,board,piece) ){
				cp(board,plan);//backtrack
				reverse(y,x,plan,piece);
				if(depth){
					adv= decide(plan,opponet,piece,depth-1);//least benefit for the opponet
					if(adv) //the opponet can make a move
						adv = 1/adv;
					else
						adv=advantage(plan,piece);
				}
				else
					adv=advantage(plan,piece);
				if(adv>bestadv){
					bestadv=adv;
					besty=y;
					bestx=x;
				}
			}
		}
	}
	reverse(besty,bestx,board,piece);//do the move
	return bestadv;
}
//peacefully close when ^C is pressed
void sigint_handler(int x){
	endwin();
	puts("Quit.");
	exit(x);
}
void mouseinput(void){
#ifndef NO_MOUSE
	MEVENT minput;
	#ifdef PDCURSES
	nc_getmouse(&minput);
	#else
	getmouse(&minput);
	#endif
	if( minput.y-4 <8 && minput.x-1<16){
		py=minput.y-4;
		px=(minput.x-1)/2;
	}
	else
		return;
	if(minput.bstate & BUTTON1_CLICKED)
		ungetch('\n');
#endif
}
void help(void){
	erase();
	header();
	attron(A_BOLD);
	mvprintw(3,0,"  **** THE CONTROLS ****");
	mvprintw(8,0,"YOU CAN ALSO USE THE MOUSE!");
	attroff(A_BOLD);
	mvprintw(4,0,"RETURN/ENTER : Put the piece");
	mvprintw(5,0,"hjkl/ARROW KEYS : Move cursor");
	mvprintw(6,0,"q : Quit");
	mvprintw(7,0,"F1 & F2 : Help on controls & gameplay");
	mvprintw(10,0,"Press a key to continue");
	curs_set(1);
	getch();
}
void gameplay(void){
	erase();
	header();
	attron(A_BOLD);
	mvprintw(3,0,"  **** THE GAMEPLAY ****");
	attroff(A_BOLD);
	move(4,0);
	printw("Players take turns placing disks on the board:\n\n");
	printw("1) Any pieces of the opponet's color that is bounded\n");
	printw("   in a straight line between the piece just placed and\n");
	printw("   another piece of the current player's color would turn\n");
	printw("   to the current player's color.\n\n");
	printw("2) You can only put pieces if at least one of your \n");
	printw("   opponet's pieces turns into your color.\n\n");
	printw("3) The game ends when neither side can do a move and\n");
	printw("   the player with more pieces wins.\n");
	getch();
}
int main(int argc , char** argv){
	int depth=2;
	if(argc>2){
		printf("Usage:%s [AIpower]",argv[0]);
		return EXIT_FAILURE;
	}
	if(argc==2){
		if(sscanf(argv[1],"%d",&depth) && depth<128 && 0<depth)
			;//already done in sscanf
		else{
			printf("That should be a number from 1 to 127.\n");
			return EXIT_FAILURE;
		}
	} 
	signal(SIGINT,sigint_handler);
	initscr();
#ifndef NO_MOUSE
	mousemask(ALL_MOUSE_EVENTS,NULL);
#endif
	noecho();
	cbreak();
	keypad(stdscr,1);
	int input;
	printw("Black plays first:\n");
	printw("Choose type of the white player (H/c)\n");
	refresh();
	input=getch();
	if(input == 'c'){
		computer[0]=depth;
		printw("Computer.\n");
	}
	else{
		computer[1]=0;
		printw("Human.\n");
	}
	refresh();
	printw("Choose type of the black player(h/C)\n");
	refresh();
	input=getch();
	if(input == 'h'){
		computer[1]=0;
		printw("Human.\n");
	}
	else{
		computer[1]=depth;
		printw("Computer.\n");
	}
	Start: 
	curs_set(0);
	py=px=0;
	memset(game,0,64);
	bool turn=0;
	bool resign=0;
	byte cantmove=0;
	game[3][3]=piece[0];
	game[4][4]=piece[0];
	game[3][4]=piece[1];
	game[4][3]=piece[1];

	Turn:
	erase();
	flushinp();
	draw(3,0);
	header();
	refresh();
	if(cantmove >=2)//both sides cant move, the game ends
		goto End;

	turn = !turn;
	if(computer[turn]){
		if(can_move(game,piece[turn])){
			mvprintw(13,0,"Thinking...");
			refresh();
			decide(game,piece[turn],piece[!turn],computer[turn]);
			cantmove=0;
		}
		else
			++cantmove;
		goto Turn;
			
	}
	
	if(!can_move(game,piece[turn])){
		++cantmove;
		goto Turn;
	}
	else{
		cantmove=0;
		while(1){ //human control
			erase();
			draw(3,0);
			header();
			if(!(computer[0]||computer[1]))
				mvprintw(0,5,"%c's turn",piece[turn]);
			refresh();
			input=getch();
			if( input==KEY_F(1) || input=='?' )
				help();
			if( input==KEY_F(2) )
				gameplay();
			if( input==KEY_MOUSE )
				mouseinput();
			if( (input=='k' || input==KEY_UP) && py>0)
				--py;
			if( (input=='j' || input==KEY_DOWN) && py<7)
				++py;
			if( (input=='h' || input==KEY_LEFT) && px>0)
				--px;
			if( (input=='l' || input==KEY_RIGHT) && px<7)
				++px;
			if( input=='q'){
				resign=1;
				goto End;
			}
			if(input=='\n' || input==KEY_ENTER){
				if(can_reverse(py,px,game,piece[turn])){
					reverse(py,px,game,piece[turn]);
					goto Turn;
				}
				
			}
		
		}
	}
	End:
	if(resign)
		mvprintw(13,0,"You resigned.");
	else if(score[0]==score[1])
		mvprintw(13,0,"Draw!!");
	else if(score[0] > score[1])
		mvprintw(13,0,"'%c' won.",piece[0]);
	else
		mvprintw(13,0,"'%c' won.",piece[1]);
		
	printw(" Wanna play again?(y/n)");
	curs_set(1);
	input=getch();
	if( resign){
		if (input=='Y' || input=='y') 
			goto Start;
	}
	else if(input != 'N' && input != 'n' && input != 'q')
		goto Start;
	endwin();
	return EXIT_SUCCESS;
}