/* -------------------------------------------------------------------------
 * Title: Target Points v1.6
 * From: migf1
 * Description:
 *	a little gambling, board game in text mode, written in ANSI C (C99)
 *	see function: do_help() for details
 * Change log:
 *	v1.6:	- added "reset game" functionality
 *		- better separation between user interface and lower level functions
 *	v1.5:	- added "save game" and "load game" functionality
 *		- more compact code + better function names
 *	v1.0:	original version
 * -------------------------------------------------------------------------
 */

#include <stdio.h>
#include <string.h>				// for strlen()
#include <stdlib.h>				// for srand(), exit()
#include <ctype.h>				// for isdigit(), tolower()
#include <time.h>				// for time() (used in srand())

#define MAXINBUF	255+1			// max chars we read in the input buffer
#define MAXFNAME	255+1			// max length for the game filename
#define MAXPNAME	5+1			// max length for the player's name

#define MAXROWS		7			// board's max height
#define MAXCOLS		7			// board's max width

#define CREDITS()	printf("%76s\n", "\"Target Points\" by migf1");

#define PROMPT(plr, mov, maxmovs, pts, maxpts)	\
	printf("[%s] M:%d/%d, P:%d/%d> ", (plr), (mov+1), (maxmovs), (pts), (maxpts) )

#define PAUSE()					\
	do{					\
		char myinbufr[255]="";		\
		printf("\npress ENTER...");	\
		fgets(myinbufr, 255, stdin);	\
	}while(0)

typedef enum { FALSE=0, TRUE } Bool;		// our custom boolean data type

						// our own data type for errors
typedef enum { ERR_NOERROR=0, ERR_FNAME, ERR_FFILE, ERR_FREAD, ERR_FWRITE } ErrCode;

typedef struct cell {				// structure of any individual cell
	Bool avail;				//	is it available for selection?
	int pos;				//	cell's position in the board
	int val;				//	cell's value
}Cell;

typedef struct gamestatus {			// structure of the game itself
	char fname[ MAXFNAME ];			//	filename for saved game
	char player[ MAXPNAME ];		//	player name
	Cell board[ MAXROWS ][ MAXCOLS ];	//	the board
	int move, maxmoves;			//	current & max number of moves
	int points, maxpoints;			//	current & max number of points
	int score;				//	final score
}GameStatus;

// ---------------------------------------------------------------------------------
// # Helper Function #
// Read s from standard input
//
char *s_get(char *s, size_t len)
{
        char *cp;

        for (cp=s; (*cp=getc(stdin)) != '\n' && (cp-s) < len-1; cp++ )
                ;					// for-loop with empty body
        *cp = '\0';					// null-terminate last character

        return s;
}

// ---------------------------------------------------------------------------------
// # Helper Function #
// Trim leading & trailing spaces from s
//
char *s_trim( char *s )
{
	char *cp1;					// for parsing the whole s
	char *cp2;					// for shifting & padding

	// trim leading & shift left remaining
	for (cp1=s; isspace(*cp1); cp1++ )		// skip leading spaces, via cp1
		;
	for (cp2=s; *cp1; cp1++, cp2++)			// shift left remaining chars, via cp2
		*cp2 = *cp1;
	*cp2-- = '\0';					// mark end of left trimmed s

	// replace trailing spaces with '\0's
	while ( cp2 > s && isspace(*cp2) )
		*cp2-- = '\0';				// pad with '\0'

	return s;
}

// ------------------------------------------------------------------------------------
// # Helper Function #
// Copy null-terminated string src to string dst (up to n-1 chars + '\0')
//
char *s_ncopy( char *dst, const char *src, int n )
{
	char *ret = dst;

	while ( (dst-ret) < n-1 && (*dst=*src) != '\0' )
		dst++, src++;

	if ( *dst )
		*dst = 0;

	return ret;
}

// ---------------------------------------------------------------------------------
// Read the player name from the standard input
// IMPORTANT:
//	this function is used INSIDE the function: init_game()
//
char *get_playername( char *player, int maxpname )
{
	if ( !player )
		return NULL;

	int temp;
	char dummy[MAXINBUF] = "";

	do {
		printf("\nPlayer name (%d chars, extras will be ignored)? ", maxpname-1);
		s_get(dummy, MAXINBUF);
		s_trim(dummy);
		temp = strlen(dummy);
		if ( temp+1 > maxpname)
			dummy[maxpname-1] = '\0';
		strcpy(player, dummy);
	} while ( !*player );

	return player;
}

// ---------------------------------------------------------------------------------
// # Helper Function #
// Read inbuf form the standard input, trim leading & trailing spaces and convert 
// its 1st character to lowercase
//
char *get_command( char *inbuf, int maxinbuf )
{
	if ( !inbuf )
		return NULL;

	s_get(inbuf, maxinbuf);			// read inbuf
	s_trim( inbuf );			// trim & trailing spaces
	*inbuf = tolower( *inbuf );		// convert 1st char to lowercase

	return inbuf;				// return inbuf

}
// ---------------------------------------------------------------------------------
// Initialize the board (it also populates it with random cell-values)
//
int init_board( int nrows, int ncols, Cell board[nrows][ncols] )
{
	register int i,j;
	int valsum = 0;

	for (i=0; i<nrows; i++)
	{
		for (j=0; j < ncols; j++) {
			board[i][j].avail = TRUE;
			board[i][j].pos = i * ncols + j;
			board[i][j].val = rand() % (nrows*ncols);
			valsum += board[i][j].val;
		}
	}

	return valsum;
}

// ---------------------------------------------------------------------------------
// Initialize the game
//
void init_game( int nrows, int ncols, int maxfname, int maxpname, GameStatus *game )
{
	s_ncopy( game->fname, "targetpoints.dat", maxfname);	// init filename
	get_playername( game->player, maxpname );		// read player name
	game->move = 0;						// init current move
	game->maxmoves = (nrows * ncols) / 2;			// init maxmoves
	game->points = 0;					// init current points
						// init both maxpoints and board cells
	game->maxpoints = init_board( nrows, ncols, game->board ) / 2;
	game->score;						// init final score

	return;
}

// ---------------------------------------------------------------------------------
// Reset the game
// It differs than init_game() in that this one leaves intact the playername and the
// filename. It resets all moves and points though, and it re-populates the cell values 
//
void reset_game( int nrows, int ncols, GameStatus *game )
{
	game->move = 0;						// init current move
	game->maxmoves = (nrows * ncols) / 2;			// init maxmoves
	game->points = 0;					// init current points
						// init both maxpoints and board cells
	game->maxpoints = init_board( nrows, ncols, game->board ) / 2;
	game->score;						// init final score

	return;
}

// ---------------------------------------------------------------------------------
// Save the game
//
ErrCode save_game( GameStatus *game )
{
	if ( !game->fname )
		return ERR_FNAME;

	FILE *fp = fopen(game->fname, "wb");
	if ( !fp )
		return ERR_FFILE;

	if ( fwrite( game, sizeof( GameStatus ), 1, fp ) != 1 )
		return ERR_FWRITE;

	fclose( fp );

	return ERR_NOERROR;
}

// ---------------------------------------------------------------------------------
// Load a game
//
ErrCode load_game( GameStatus *game )
{
	if ( !game->fname )
		return ERR_FNAME;

	FILE *fp = fopen(game->fname, "rb");
	if ( !fp )
		return ERR_FFILE;

	if ( fread( game, sizeof( GameStatus ), 1, fp ) != 1 )
		return ERR_FREAD;

	fclose( fp );

	return ERR_NOERROR;
}

// ---------------------------------------------------------------------------------
/*** DISABLED: UNUSED

void draw_cells( int nrows, int ncols, Cell board[nrows][ncols] )
{
	register int i,j;

	for (i=0; i<nrows; i++)
	{
		for (j=0; j < ncols; j++)
			printf("+---");
		puts("+");
		for (j=0; j < ncols; j++)
			printf("| %2d ", board[i][j].val);
		puts("|");
	}
	for (j=0; j < ncols; j++)
		printf("+---");
	puts("+");

	return;
}
***/

// ---------------------------------------------------------------------------------
// Draw the board diagrams on the screen, the left one with available posistions,
// the right one with already selected cell-values (if cheat is TRUE, the right
// diagram shows ALL cell-values, instead).
//
void show_board( int nrows, int ncols, Cell board[nrows][ncols], Bool cheat )
{
	register int i,j;

	for (i=0; i < nrows; i++)
	{
		for (j=0; j < ncols; j++)
			printf("|----");
		printf("|\t");
		for (j=0; j < ncols; j++)
			printf("-----");
		puts("-");

		for (j=0; j < ncols; j++)
		{
			if ( board[i][j].avail )
				printf("| %2d ", board[i][j].pos);
			else
				printf("| ## ");
		}
		printf("|\t");
		for (j=0; j < ncols; j++)
		{
			if ( board[i][j].avail && !cheat)
				printf("|    ");
			else
				printf("| %2d ", board[i][j].val);
		}
		puts("|");
	}
	for (j=0; j < ncols; j++)
		printf("|----");
	printf("|\t");
	for (j=0; j < ncols; j++)
		printf("-----");
	puts("-");

	return;
}

// ---------------------------------------------------------------------------------
// Handle the "help" command: h
//
void do_help( void )
{
	puts("\n\tThis is a little gambling game written in ANSI C, by migf1.");

	puts("\n\tYour task is to collect the target amount of points in as many");
	puts("\tmoves as the half of the total cells of the board.");

	puts("\n\tCells are initially populated with random values ranging from");
	puts("\t0 to the total number of cells - 1 (e.g.: from 0 to 48 for a");
	puts("\t7x7 board). Duplicated values may appear in two or more cells.");
	puts("\tThe target amount of points you are after, equals to the half");
	puts("\tof the sum of all those values (sum of values / 2)");

	puts("\n\tTo choose a cell you enter its positioning number, as shown");
	puts("\tin the left diagram. The value it holds will appear in the");
	puts("\tright diagram and it will be added to your current points.");

	puts("\n\tIf you run out of moves before collecting the target amount");
	puts("\tof points, the game ends and you get 0 score. If you manage");
	puts("\tto collect the points before running out of moves, then the");
	puts("\tpoints collected beyond the targeted amount are multiplied");
	puts("\tby the moves you had left, and the result is your score");

	puts("\n\tThe prompt always shows your current move and points, along");

	PAUSE();

	puts("\n\twith the moves you have left, and the targeted amount of");
	puts("\tpoints to be gathered. So make sure you check it regularly");
	puts("\t(M stands for move, P for points).");

	puts("\n\tYou can also use the following commands at the prompt:");
	puts("");
	puts("\th\tthis help you are reading right now");
	puts("\tt\tshow current stats");
	puts("\ts\tsave current game");
	puts("\tl\tload previously saved game (current game data get erased!)");
	puts("\tr\treset game (everything but the playername are reset)");
	puts("\tx\texit the game (note: you'll get 0 score!)");

	puts("\n\tThe game ends either when you run out of moves, you enter");
	puts("\tx at the prompt, or you gather more points than the targeted");
	puts("\tamount (equal or more). In any case, all the cell-values will");
	puts("\tbe revealed in the right diagram, just before the termination");
	puts("\tof the program.");

	puts("\n\tHave fun!");

	PAUSE();

	return;
}

// ---------------------------------------------------------------------------------
// Handle the "stats" command: t
//
void do_stats( GameStatus *game )
{
	printf(	"\n\tyou've made %d move(s), having collected %d points\n",
		game->move, game->points );
	printf(	"\tyou have %d move(s) left, to collect %d more point(s)\n\n",
		game->maxmoves - game->move, game->maxpoints - game->points
	);

	return;
}

// ---------------------------------------------------------------------------------
// Handle the "save game" command: s
//
Bool do_savegame( GameStatus *game )
{
	char inbuf[MAXINBUF] = "";
	ErrCode errcode;

	printf("you are about to save the game, please confirm (y/) ");
	get_command(inbuf, MAXINBUF);
	if ( !*inbuf || *inbuf != 'y' ) {
		puts("\n\tsaving the game aborted by the user\n");
		return FALSE;
	}

	printf("\n\tsaving the game... ");

	errcode = save_game( game );

	if ( errcode == ERR_NOERROR ) {
		printf("succeeded\n\n");
		return TRUE;
	}

	if ( errcode == ERR_FNAME )
		printf("failed (internal error)\n\n");
	else if ( errcode == ERR_FFILE )
		printf("failed (file not found)\n\n");
	else if ( errcode == ERR_FWRITE)
		printf("failed (write error)\n\n");
	else
		printf("failed (uknown error)\n\n");

	return FALSE;
}

// ---------------------------------------------------------------------------------
// Handle the "load game" command: l
//
Bool do_loadgame( GameStatus *game )
{
	char inbuf[MAXINBUF] = "";
	ErrCode errcode;

	printf("loading a previous game will delete this one, please confirm (y/) ");
	get_command(inbuf, MAXINBUF);
	if ( !*inbuf || *inbuf != 'y' ) {
		puts("\n\tloading a previously saved game aborted by the user\n");
		return FALSE;
	}

	printf("\n\tloading game... ");

	errcode = load_game( game );

	if ( errcode == ERR_NOERROR ) {
		printf("succeeded\n\n");
		return TRUE;
	}

	if ( errcode == ERR_FNAME )
		printf("failed (internal error)\n\n");
	else if ( errcode == ERR_FFILE )
		printf("failed (file not found)\n\n");
	else if ( errcode == ERR_FREAD)
		printf("failed (read error)\n\n");
	else
		printf("failed (uknown error)\n\n");

	return FALSE;
}

// ---------------------------------------------------------------------------------
// Handle the "reset game" command: r
//
Bool do_resetgame( int nrows, int ncols, GameStatus *game )
{
	char inbuf[MAXINBUF] = "";

	printf("reset game will erase all moves & cell-values, please confirm (y/) ");
	get_command(inbuf, MAXINBUF);
	if ( !*inbuf || *inbuf != 'y' ) {
		puts("\n\treset game aborted by the user\n");
		return FALSE;
	}

	reset_game( nrows, ncols, game );
	puts("\n\tgame was reset\n");

	return TRUE;
}

// ---------------------------------------------------------------------------------
// Handle non-numerical commands
//
void exec_charcmd( char c, int nrows, int ncols, GameStatus *game)
{
	switch ( c )
	{
	case 'x':
	case '\0':
		break;

	case 'h':
		do_help();
		break;

	case 't':
		do_stats( game );
		break;

	case 'r':
		do_resetgame( nrows, ncols, game );
		break;
	case 's':
		do_savegame( game );
		break;

	case 'l':
		do_loadgame( game );
		break;

	default:
		puts("\a\n\tinvalid command, type h for help\n");
		break;
	}

	return;
}

// ---------------------------------------------------------------------------------
// Handle numerical commands (expecting them to be board positions)
//
Bool exec_poscmd( char *inbuf, int nrows, int ncols, GameStatus *game)
{
	int i, j, pos;

	pos = atoi( inbuf );
	if ( pos < 0 || pos > nrows*ncols-1 ) {
		puts("\a\n\tinvalid position\n");
		return FALSE;
	}

	i = pos / ncols;
	j = pos % ncols;
	if ( !game->board[ i ][ j ].avail ) {
		puts("\a\n\tyou have already played that position\n");
		return FALSE;
	}

	game->board[ i ][ j ].avail = FALSE;
	(game->move)++;
	(game->points) += game->board[ i ][ j ].val;
	printf("\n\t%d points added to your bucket!\n\n", game->board[ i ][ j ].val);

	return TRUE;
}

// ---------------------------------------------------------------------------------
// Calculate and show the final score on the screen
//
void show_finalscore( GameStatus *game )
{
	if ( game->points >= game->maxpoints ) {
		printf("\t\a\a*** YES, YOU MADE IT! You collected %d points in %d moves(s)\n", game->points, game->move);
		game->score = (game->points - game->maxpoints + 1) * (game->maxmoves - game->move + 1);
		printf("\t*** YOUR SCORE IS: %d\n", game->score);
	}
	else {
		game->score = 0;
		puts("\n\tSORRY, YOU FAILED! NO SCORE THIS TIME!");
	}

	return;
}

// ---------------------------------------------------------------------------------
int main( void )
{
	char inbuf[MAXINBUF] = "";			// for reading commands
	GameStatus game;				// initialization is done below

	srand( time(NULL) );				// init the random generator
							// initialize the game (it also
	init_game(MAXROWS, MAXCOLS, MAXFNAME, MAXPNAME, &game);	// reads the player name)
	putchar('\n');

	do						// the main loop of the game
	{
							// display the board diagrams
		show_board( MAXROWS, MAXCOLS, game.board, FALSE );

		CREDITS();				// display the credits line
		PROMPT(	game.player, game.move,		// display the prompt
			game.maxmoves, game.points, game.maxpoints );

		get_command( inbuf, MAXINBUF );		// get user command
		if ( isdigit(*inbuf) )			// handle numerical command
			exec_poscmd( inbuf, MAXROWS, MAXCOLS, &game );
		else					// handle non-numerical command
			exec_charcmd( *inbuf, MAXROWS, MAXCOLS, &game );

	} while( *inbuf != 'x'				// game ends either when x
		&& game.move < game.maxmoves		// or run out of moves
		&& game.points < game.maxpoints );	// or maxpoints have been reached

	show_finalscore( &game );			// calc & display the final score

							// reveal all the board cells
	puts("\n\thave a look at the full board, before exiting\n");
	show_board( MAXROWS, MAXCOLS, game.board, TRUE );
	PAUSE();

	exit( EXIT_SUCCESS );
}