5 files changed, 461 insertions, 30 deletions

diff --git a/apps/plugins/chessbox/chessbox.c b/apps/plugins/chessbox/chessbox.c
index ab75765885..8e3d889dff 100644
--- a/apps/plugins/chessbox/chessbox.c
+++ b/apps/plugins/chessbox/chessbox.c
@@ -672,7 +672,6 @@ void cb_start_viewer(char* filename){
                             curr_ply = curr_ply->prev_node;
                         } else {
                             rb->splash ( 200 , "At the begining of the game" );
-                            cb_drawboard();
                             break;
                         }
                         board[locn[curr_ply->row_from][curr_ply->column_from]] 
@@ -952,7 +951,8 @@ struct cb_command cb_getcommand (void) {
 /* ---- game main loop ---- */
 void cb_play_game(void) {
     struct cb_command command;
-    char move_buffer[10];
+    struct pgn_game_node *game;
+    char move_buffer[20];
 
     /* init status */
     bool exit = false;
@@ -961,9 +961,13 @@ void cb_play_game(void) {
 
     /* init board */
     GNUChess_Initialize();
+
+    /* init PGN history data structures */
+    game = pgn_init_game(rb);
     
     /* restore saved position, if saved */
     cb_restoreposition();
+    /* TODO: save/restore the PGN history of unfinished games */
     
     /* draw the board */
     /* I don't like configscreens, start game inmediatly */
@@ -973,17 +977,23 @@ void cb_play_game(void) {
         if ( mate ) {
             rb->splash ( 500 , "Checkmate!" );
             rb->button_get(true);
+            pgn_store_game(rb, game);
             GNUChess_Initialize();
+            game = pgn_init_game(rb);
             cb_drawboard();
         }
         command = cb_getcommand ();
         switch (command.type) {
             case COMMAND_MOVE:
-                if ( ! VerifyMove ( command.mv_s , 0 , &command.mv ) ) {
+                if ( ! VerifyMove (opponent, command.mv_s , 0 , &command.mv, move_buffer ) ) {
                     rb->splash ( 50 , "Illegal move!" );
                     cb_drawboard();
                 } else {
                     cb_drawboard();
+
+                    /* Add the ply to the PGN history (in algebraic notation) */
+                    pgn_append_ply(rb, game, opponent, move_buffer, mate);
+
                     rb->splash ( 0 , "Thinking..." );
 #ifdef HAVE_ADJUSTABLE_CPU_FREQ
                     rb->cpu_boost ( true );
@@ -992,6 +1002,15 @@ void cb_play_game(void) {
 #ifdef HAVE_ADJUSTABLE_CPU_FREQ
                     rb->cpu_boost ( false );
 #endif
+                    /* Add the ply to the PGN history (in algebraic notation) and check
+                     * for the result of the game which is only calculated in SelectMove
+                     */
+                    if (move_buffer[0] != '\0'){
+                        pgn_append_ply(rb, game, computer, move_buffer, mate);
+                    } else {
+                        pgn_set_result(rb, game, mate);
+                    }
+
                     if ( wt_command == COMMAND_QUIT ) {
                         exit = true;
                         break;
@@ -1002,6 +1021,7 @@ void cb_play_game(void) {
 #ifdef COMMAND_RESTART
             case COMMAND_RESTART:
                 GNUChess_Initialize();
+                game = pgn_init_game(rb);
                 cb_drawboard();
                 break;
 #endif
@@ -1017,7 +1037,10 @@ void cb_play_game(void) {
 
                 /* init board */
                 GNUChess_Initialize();
-    
+
+                /* init PGN history data structures */
+                game = pgn_init_game(rb);
+
                 /* restore saved position, if saved */
                 cb_restoreposition();
 
@@ -1040,6 +1063,16 @@ void cb_play_game(void) {
 #ifdef HAVE_ADJUSTABLE_CPU_FREQ
                 rb->cpu_boost ( false );
 #endif
+
+                /* Add the ply to the PGN history (in algebraic notation) and check
+                 * for the result of the game which is only calculated in SelectMove
+                 */
+                if (move_buffer[0] != '\0'){
+                    pgn_append_ply(rb, game, computer, move_buffer, mate);
+                } else {
+                    pgn_set_result(rb, game, mate);
+                }
+
                 if ( wt_command == COMMAND_QUIT ) {
                     exit = true;
                     break;
@@ -1057,6 +1090,7 @@ void cb_play_game(void) {
     }
     
     cb_saveposition();
+    /* TODO: save/restore the PGN history of unfinished games */
     rb->lcd_setfont(FONT_UI);
 
 }
diff --git a/apps/plugins/chessbox/chessbox_pgn.c b/apps/plugins/chessbox/chessbox_pgn.c
index db95210a8d..fb04f6ac38 100644
--- a/apps/plugins/chessbox/chessbox_pgn.c
+++ b/apps/plugins/chessbox/chessbox_pgn.c
@@ -188,7 +188,8 @@
     #error CHESSBOX: Unsupported keypad
 #endif
 
-#define LOG_FILE  PLUGIN_DIR "/chessbox.log"
+#define PGN_FILE  PLUGIN_GAMES_DIR  "/chessbox.pgn"
+#define LOG_FILE  PLUGIN_GAMES_DIR  "/chessbox.log"
 int loghandler;
 
 struct plugin_api* rb;
@@ -520,6 +521,180 @@ void pgn_to_coords(struct pgn_ply_node* ply){
     color[locn[ply->row_from][ply->column_from]] = neutral;
 }
 
+void coords_to_pgn(struct pgn_ply_node* ply){
+    int pos = 0,i,j;
+    unsigned short moving_piece = board[locn[ply->row_from][ply->column_from]];
+    char unambiguous_position;
+    bool found = false;
+    char alg_move[5];
+    char move_buffer[10];
+    short move;
+    if (moving_piece == king){
+        /* check castling */
+        if (ply->column_from == 4 && ply->column_to == 6){
+            /* castling kingside */
+            rb->strcpy(ply->pgn_text,"O-O");
+            ply->castle = true;
+        } else if (ply->column_from == 4 && ply->column_to == 2){
+            /* castling queenside */
+            rb->strcpy(ply->pgn_text,"O-O-O");
+        } else {
+            if (board[locn[ply->row_to][ply->column_to]] != no_piece){
+                rb->snprintf(ply->pgn_text,10,"Kx%c%c",'a'+ply->column_to,
+                                   '1'+ply->row_to);
+            } else {
+                rb->snprintf(ply->pgn_text,10,"K%c%c",'a'+ply->column_to,
+                                   '1'+ply->row_to);
+            }
+        }
+    } else if (moving_piece == pawn){
+        if (ply->column_from != ply->column_to){
+            /* check enpassant */
+            if (board[locn[ply->row_to][ply->column_to]] == no_piece){
+                ply->enpassant = true;
+            }
+            /* check promotions when taking a piece */
+            if (ply->row_to == 0 || ply->row_to == 7) {
+                ply->promotion = true;
+                ply->promotion_piece = queen;
+                rb->snprintf(ply->pgn_text,10,"%cx%c%c=D", 'a'+ply->column_from,
+                                   'a'+ply->column_to,'1'+ply->row_to);
+            } else {
+                rb->snprintf(ply->pgn_text,10,"%cx%c%c", 'a'+ply->column_from,
+                                   'a'+ply->column_to,'1'+ply->row_to);
+            }
+        } else {
+            /* check promotions when not taking a piece */
+            if (ply->row_to == 0 || ply->row_to == 7) {
+                ply->promotion = true;
+                ply->promotion_piece = queen;
+                rb->snprintf(ply->pgn_text,10,"%c%c=D", 'a'+ply->column_to,
+                                   '1'+ply->row_to);
+            } else {
+                rb->snprintf(ply->pgn_text,10,"%c%c", 'a'+ply->column_to,
+                                   '1'+ply->row_to);
+            }
+        }
+    } else {
+        /* verify ambiguous moves for the different kinds of pieces */
+        unambiguous_position = '\0';
+        if (moving_piece == knight){
+            for (i=0;i<8;i++){
+                if (ply->row_to + kn_offs[i][0] >= 0 && ply->row_to + kn_offs[i][0] <= 7
+                    && ply->column_to + kn_offs[i][1] >= 0 && ply->column_to + kn_offs[i][1] <= 7
+                    && board[locn[ply->row_to + kn_offs[i][0]][ply->column_to + kn_offs[i][1]]] == knight
+                    && color[locn[ply->row_to + kn_offs[i][0]][ply->column_to + kn_offs[i][1]]] == ply->player
+                    && (ply->row_to + kn_offs[i][0] != ply->row_from 
+                        || ply->column_to + kn_offs[i][1] != ply->column_from)){
+                    if (ply->row_to + kn_offs[i][0] != ply->row_from){
+                        unambiguous_position = '1' + ply->row_from;
+                    } else {
+                        unambiguous_position = 'a' + ply->column_from;
+                    }
+                    break;
+                }
+            }
+        }
+        if (moving_piece == rook || moving_piece == queen){
+            found = false;
+            for (i=0;i<4;i++){
+                j=1;
+                while (ply->row_to+(j*rk_offs[i][0]) >= 0 && ply->row_to+(j*rk_offs[i][0]) <= 7 &&
+                       ply->column_to+(j*rk_offs[i][1]) >= 0 && ply->column_to+(j*rk_offs[i][1]) <= 7){
+                    if (board[locn[ply->row_to+(j*rk_offs[i][0])][ply->column_to+(j*rk_offs[i][1])]] != no_piece) {
+                        if (board[locn[ply->row_to+(j*rk_offs[i][0])][ply->column_to+(j*rk_offs[i][1])]] == moving_piece &&
+                            color[locn[ply->row_to+(j*rk_offs[i][0])][ply->column_to+(j*rk_offs[i][1])]] == ply->player &&
+                            (ply->row_to+(j*rk_offs[i][0]) != ply->row_from
+                             || ply->column_to+(j*rk_offs[i][1]) != ply->column_from)) {
+                            if (ply->row_to+(j*rk_offs[i][0]) != ply->row_from){
+                                unambiguous_position = '1' + ply->row_from;
+                            } else {
+                                unambiguous_position = 'a' + ply->column_from;
+                            }
+                            found = true;
+                        }
+                        break;
+                    }
+                    j++;
+                }
+                if (found) {
+                    break;
+                }
+            }
+        }
+        if (moving_piece == bishop || (moving_piece == queen && !found)){
+            for (i=0;i<4;i++){
+                j=1;
+                while (ply->row_to+(j*bp_offs[i][0]) >= 0 && ply->row_to+(j*bp_offs[i][0]) <= 7 &&
+                       ply->column_to+(j*bp_offs[i][1]) >= 0 && ply->column_to+(j*bp_offs[i][1]) <= 7){
+                    if (board[locn[ply->row_to+(j*bp_offs[i][0])][ply->column_to+(j*bp_offs[i][1])]] != no_piece) {
+                        if (board[locn[ply->row_to+(j*bp_offs[i][0])][ply->column_to+(j*bp_offs[i][1])]] == moving_piece &&
+                            color[locn[ply->row_to+(j*bp_offs[i][0])][ply->column_to+(j*bp_offs[i][1])]] == ply->player &&
+                            (ply->row_to+(j*bp_offs[i][0]) != ply->row_from
+                             || ply->column_to+(j*bp_offs[i][1]) != ply->column_from)) {
+                            if (ply->row_to+(j*bp_offs[i][0]) != ply->row_from){
+                                unambiguous_position = '1' + ply->row_from;
+                            } else {
+                                unambiguous_position = 'a' + ply->column_from;
+                            }
+                            found = true;
+                        }
+                        break;
+                    }
+                    j++;
+                }
+                if (found) {
+                    break;
+                }
+            }
+        }
+        /* generate the first portion of the PGN text
+         * always as white so all uppercase, black/white considerations
+         * will be useful for FEN notation but not in this case
+         */
+        if (unambiguous_position == '\0'){
+            if (board[locn[ply->row_to][ply->column_to]] != no_piece){
+                rb->snprintf(ply->pgn_text,10,"%cx%c%c",
+                                   pgn_from_piece(moving_piece,white) ,
+                                   'a'+ply->column_to, '1'+ply->row_to);
+            } else {
+                rb->snprintf(ply->pgn_text,10,"%c%c%c",
+                                   pgn_from_piece(moving_piece,white) ,
+                                   'a'+ply->column_to, '1'+ply->row_to);
+            }
+        } else {
+            if (board[locn[ply->row_to][ply->column_to]] != no_piece){
+                rb->snprintf(ply->pgn_text,10,"%c%cx%c%c",
+                                   pgn_from_piece(moving_piece,white) ,
+                                   unambiguous_position, 'a'+ply->column_to,
+                                   '1'+ply->row_to);
+            } else {
+                rb->snprintf(ply->pgn_text,10,"%c%c%c%c",
+                                   pgn_from_piece(moving_piece,white) ,
+                                   unambiguous_position, 'a'+ply->column_to,
+                                   '1'+ply->row_to);
+            }
+        }
+    }
+    /* update the board */
+    rb->snprintf(alg_move,5,"%c%c%c%c",'a' + ply->column_from, '1' + ply->row_from,
+                'a' + ply->column_to, '1' + ply->row_to);
+    /* The function returns false if the move is invalid, but since we're
+     * replaying the game, that should not be posible
+     */
+    VerifyMove (ply->player, alg_move , 0 , &move, move_buffer );
+
+    /* add check/mate indicators */
+    for (pos=0;ply->pgn_text[pos] != '\0';pos++);
+    if (ply->checkmate) {
+        ply->pgn_text[pos] = '#'; pos++;
+        ply->pgn_text[pos] = '\0'; pos++;
+    } else if (move_buffer[4] == '+'){
+        ply->pgn_text[pos] = '+'; pos++;
+        ply->pgn_text[pos] = '\0'; pos++;
+    }
+}
+
 char * get_game_text(int selected_item, void *data, char *buffer){
     int i;
     struct pgn_game_node *temp_node = (struct pgn_game_node *)data;
@@ -538,11 +713,21 @@ char * get_game_text(int selected_item, void *data, char *buffer){
     return buffer;
 }
 
+void write_pgn_token(int fhandler, char *buffer, size_t *line_length){
+    if (*line_length + rb->strlen(buffer) + 1 > 80){
+        rb->fdprintf(fhandler,"\n");
+        *line_length = 0;
+    }
+    rb->fdprintf(fhandler,"%s ",buffer);
+    *line_length += (rb->strlen(buffer) + 1);
+}
+
 /* ---- api functions ---- */
 struct pgn_game_node* pgn_list_games(struct plugin_api* api,const char* filename){
     int fhandler;
     char line_buffer[128];
-    struct pgn_game_node size_node, *first_game = NULL, *curr_node = NULL, *temp_node;
+    struct pgn_game_node size_node, *first_game = NULL;
+    struct pgn_game_node *curr_node = NULL, *temp_node;
     unsigned short game_count = 1;
     int line_count = 0;
     bool header_start = true, game_start = false;
@@ -577,7 +762,9 @@ struct pgn_game_node* pgn_list_games(struct plugin_api* api,const char* filename
         } else {
             if (line_buffer[0] == '['){
                 process_tag(curr_node, line_buffer);
-            } else if (line_buffer[0] == '\r' || line_buffer[0] == '\n' || line_buffer[0] == '\0'){
+            } else if (line_buffer[0] == '\r'
+                       || line_buffer[0] == '\n'
+                       || line_buffer[0] == '\0'){
                 if (game_start) {
                     game_start = false;
                 } else {
@@ -594,7 +781,8 @@ struct pgn_game_node* pgn_list_games(struct plugin_api* api,const char* filename
     return first_game;
 }
 
-struct pgn_game_node* pgn_show_game_list(struct plugin_api* api, struct pgn_game_node* first_game){
+struct pgn_game_node* pgn_show_game_list(struct plugin_api* api,
+                                         struct pgn_game_node* first_game){
     int curr_selection = 0;
     int button;
     struct gui_synclist games_list;
@@ -638,8 +826,10 @@ struct pgn_game_node* pgn_show_game_list(struct plugin_api* api, struct pgn_game
     }
 }
 
-void pgn_parse_game(struct plugin_api* api, const char* filename, struct pgn_game_node* selected_game){
-    struct pgn_ply_node size_ply, *first_ply = NULL, *temp_ply = NULL, *curr_node = NULL;
+void pgn_parse_game(struct plugin_api* api, const char* filename,
+                    struct pgn_game_node* selected_game){
+    struct pgn_ply_node size_ply, *first_ply = NULL;
+    struct pgn_ply_node *temp_ply = NULL, *curr_node = NULL;
     int fhandler, i;
     char line_buffer[128];
     char token_buffer[10];
@@ -682,16 +872,20 @@ void pgn_parse_game(struct plugin_api* api, const char* filename, struct pgn_gam
                     temp_ply->prev_node = curr_node;
                     curr_node = temp_ply;
                 }
-                rb->fdprintf(loghandler,"player: %u; pgn: %s; from: %u,%u; to: %u,%u; taken: %u.\n",
-                             temp_ply->player, temp_ply->pgn_text, temp_ply->row_from, temp_ply->column_from,
-                             temp_ply->row_to, temp_ply->column_to, temp_ply->taken_piece);
+                rb->fdprintf(loghandler,
+                    "player: %u; pgn: %s; from: %u,%u; to: %u,%u; taken: %u.\n",
+                             temp_ply->player, temp_ply->pgn_text, temp_ply->row_from,
+                             temp_ply->column_from, temp_ply->row_to,
+                             temp_ply->column_to, temp_ply->taken_piece);
             }
         }
     }
 
     rb->close(loghandler);
 
-    /* additional dummy ply to represent end of file without loosing the previous node's pointer */
+    /* additional dummy ply to represent end of file without
+     *loosing the previous node's pointer
+     */
     if (first_ply != NULL){
         temp_ply = (struct pgn_ply_node *)pl_malloc(sizeof size_ply);
         temp_ply->player = neutral;
@@ -701,3 +895,170 @@ void pgn_parse_game(struct plugin_api* api, const char* filename, struct pgn_gam
     selected_game->first_ply = first_ply;
     rb->close(fhandler);
 }
+
+struct pgn_game_node* pgn_init_game(struct plugin_api* api){
+    struct pgn_game_node game_size, *game;
+    struct pgn_ply_node ply_size, *ply;
+    struct tm *current_time;
+
+    rb = api;
+
+    if (bufptr == NULL){
+        pl_malloc_init();
+    }
+
+    /* create an "end of game" dummy ply and assign defaults */
+    ply = (struct pgn_ply_node *)pl_malloc(sizeof ply_size);
+    ply->player = neutral;
+    ply->pgn_text[0] = '\0';
+    ply->prev_node = NULL;
+    ply->next_node = NULL;
+
+    /* create the game and assign defaults */
+    game = (struct pgn_game_node *)pl_malloc(sizeof game_size);
+    game->game_number = 0;
+    rb->strcpy(game->white_player,"Player");
+    rb->strcpy(game->black_player,"GnuChess");
+    current_time = rb->get_time();
+    if (current_time->tm_year < 100){
+        rb->snprintf(game->game_date,11,"????.??.??");
+    } else {
+        rb->snprintf(game->game_date,11,"%4u.%2u.%2u",current_time->tm_year + 1900,
+                     current_time->tm_mon + 1, current_time->tm_mday);
+    }
+    rb->strcpy(game->result,"*");
+    game->pgn_line = 0;
+    game->first_ply = ply;
+    game->next_node = NULL;
+
+    return game;
+}
+
+void pgn_append_ply(struct plugin_api* api, struct pgn_game_node* game,
+                    unsigned short ply_player, char *move_buffer, bool is_mate){
+    struct pgn_ply_node ply_size, *ply, *temp;
+
+    rb = api;
+
+    ply = (struct pgn_ply_node *)pl_malloc(sizeof ply_size);
+    ply->player = ply_player;
+    ply->column_from = move_buffer[0] - 'a';
+    ply->row_from = move_buffer[1] - '1';
+    ply->column_to = move_buffer[2] - 'a';
+    ply->row_to = move_buffer[3] - '1';
+    ply->castle = false;
+    ply->promotion = false;
+    ply->enpassant = false;
+    ply->promotion_piece = no_piece;
+    ply->taken_piece = no_piece;
+    ply->draw = false;
+    ply->checkmate = is_mate;
+
+    /* move the pointer to the "end of game" marker ply */
+    for (temp=game->first_ply;temp->next_node!=NULL;temp=temp->next_node);
+
+    /* arrange the pointers to insert the ply before the marker */
+    ply->next_node = temp;
+    ply->prev_node = temp->prev_node;
+    if (temp->prev_node == NULL){
+        game->first_ply = ply;
+    } else {
+        temp->prev_node->next_node = ply;
+    }
+    temp->prev_node = ply;
+}
+
+void pgn_set_result(struct plugin_api* api, struct pgn_game_node* game,
+                    bool is_mate){
+
+    rb = api;
+
+    struct pgn_ply_node *ply;
+    for(ply=game->first_ply;ply->next_node != NULL;ply=ply->next_node);
+    if (is_mate){
+        ply->prev_node->checkmate = true;
+    } else {
+        ply->prev_node->draw = true;
+    }
+}
+
+void pgn_store_game(struct plugin_api* api, struct pgn_game_node* game){
+    int fhandler;
+    struct pgn_ply_node *ply;
+    unsigned ply_count;
+    size_t line_length=0;
+    char buffer[10];
+
+    rb = api;
+
+    GNUChess_Initialize();
+
+    ply_count=0;
+    ply=game->first_ply;
+    while (ply->next_node!=NULL){
+        coords_to_pgn(ply);
+        if (ply->checkmate){
+            if (ply->player == white){
+                rb->strcpy(game->result,"1-0");
+            } else {
+                rb->strcpy(game->result,"0-1");
+            }
+        }
+        if (ply->draw){
+            rb->strcpy(game->result,"1/2-1/2");
+        }
+        ply=ply->next_node;
+        ply_count++;
+    }
+
+    fhandler = rb->open(PGN_FILE, O_WRONLY|O_CREAT|O_APPEND);
+
+
+    /* the first 7 tags are mandatory according to the PGN specification so we
+     * have to include them even if the values don't make much sense
+     */
+    rb->fdprintf(fhandler,"[Event \"Casual Game\"]\n");
+    rb->fdprintf(fhandler,"[Site \"?\"]\n");
+    rb->fdprintf(fhandler,"[Date \"%s\"]\n",game->game_date);
+    rb->fdprintf(fhandler,"[Round \"?\"]\n");
+    rb->fdprintf(fhandler,"[White \"%s\"]\n",game->white_player);
+    rb->fdprintf(fhandler,"[Black \"%s\"]\n",game->black_player);
+    rb->fdprintf(fhandler,"[Result \"%s\"]\n",game->result);
+    rb->fdprintf(fhandler,"[PlyCount \"%u\"]\n",ply_count);
+
+    /* leave a blank line between the tag section and the game section */
+    rb->fdprintf(fhandler,"\n");
+
+    /* write the plies in several lines of up to 80 characters */
+    for (ply_count=0, ply=game->first_ply;ply->next_node!=NULL;
+         ply=ply->next_node,ply_count++){
+        /* write the move number */
+        if (ply->player == white){
+            rb->snprintf(buffer,10,"%u.",(ply_count/2)+1);
+            write_pgn_token(fhandler, buffer, &line_length);
+        }
+        /* write the actual move */
+        write_pgn_token(fhandler,ply->pgn_text,&line_length);
+        /* write the result of the game at the end */
+        if (ply->checkmate){
+            if (ply->player == white){
+                write_pgn_token(fhandler,"1-0",&line_length);
+            } else {
+                write_pgn_token(fhandler,"0-1",&line_length);
+            }
+            break;
+        } else if (ply->draw){
+            write_pgn_token(fhandler,"1/2-1/2",&line_length);
+            break;
+        } else if (ply->next_node->player == neutral) {
+            /* unknown end of the game */
+            write_pgn_token(fhandler,"*",&line_length);
+            break;
+        }
+    }
+
+    /* leave a blank line between the tag section and the game section */
+    rb->fdprintf(fhandler,"\n\n");
+
+    rb->close(fhandler);    
+}
diff --git a/apps/plugins/chessbox/chessbox_pgn.h b/apps/plugins/chessbox/chessbox_pgn.h
index e57b45dc5a..c4dd5c671f 100644
--- a/apps/plugins/chessbox/chessbox_pgn.h
+++ b/apps/plugins/chessbox/chessbox_pgn.h
@@ -33,6 +33,8 @@ struct pgn_ply_node {
     bool enpassant;
     bool castle;
     bool promotion;
+    bool checkmate;
+    bool draw;
     struct pgn_ply_node* prev_node;
     struct pgn_ply_node* next_node;
 };
@@ -54,14 +56,35 @@ struct pgn_game_node {
  * the user selects a game, that obviously saves processing
  * and speeds up response when the user selects the file
  */
-struct pgn_game_node* pgn_list_games(struct plugin_api* api, const char* filename);
+struct pgn_game_node* pgn_list_games(struct plugin_api* api,
+                                     const char* filename);
 
 /* Show the list of games found in a file and allow the user
  * to select a game to be parsed and showed
  */
-struct pgn_game_node* pgn_show_game_list(struct plugin_api* api, struct pgn_game_node* first_game);
+struct pgn_game_node* pgn_show_game_list(struct plugin_api* api,
+                                         struct pgn_game_node* first_game);
 
 /* Parse the pgn string of a game and assign it to the move
  * list in the structure
  */
-void pgn_parse_game(struct plugin_api* api, const char* filename, struct pgn_game_node* selected_game);
+void pgn_parse_game(struct plugin_api* api, const char* filename,
+                    struct pgn_game_node* selected_game);
+
+/* Initialize a new game structure with default values and make
+ * it ready to store the history of a newly played match
+ */
+struct pgn_game_node* pgn_init_game(struct plugin_api* api);
+
+/* Add a new ply to the game structure based on the positions */
+void pgn_append_ply(struct plugin_api* api, struct pgn_game_node* game,
+                    unsigned short ply_player, char *move_buffer, bool is_mate);
+
+/* Set the result of the game if it was reached during the opponent's ply
+ */
+void pgn_set_result(struct plugin_api* api, struct pgn_game_node* game,
+                    bool is_mate);
+
+/* Store a complete game in the PGN history file
+ */
+void pgn_store_game(struct plugin_api* api, struct pgn_game_node* game);
diff --git a/apps/plugins/chessbox/gnuchess.c b/apps/plugins/chessbox/gnuchess.c
index e72a489a0d..3574dd6fbe 100644
--- a/apps/plugins/chessbox/gnuchess.c
+++ b/apps/plugins/chessbox/gnuchess.c
@@ -1116,10 +1116,9 @@ static short i,alpha,beta,score,tempb,tempc,tempsf,tempst,xside,rpt;
   /*OutputMove();*/
 
   short index;
-  for (index=0;index<4;index++){
-    move_buffer[index] = mvstr1[index];
+  for (index=0;index<5;index++){
+      move_buffer[index] = mvstr1[index];
   }
-  move_buffer[index] = '\0';
 
   if (score == -9999 || score == 9998) mate = true;
   if (mate) hint = 0;
@@ -2231,26 +2230,30 @@ void SetTimeControl( void )
   ExitChess();
 }*/
 
-int VerifyMove(char s[],short iop,unsigned short *mv)
+int VerifyMove(short player, char s[],short iop,unsigned short *mv, char *move_buffer)
 
 /*
    Compare the string 's' to the list of legal moves available for the 
-   opponent. If a match is found, make the move on the board. 
+   player. If a match is found, make the move on the board. This was originally
+   fixed for the opponent, but allowing the player to be specified will make
+   possible to use GnuChess as a human vs human game verifier. It also allows
+   the PGN functions to verify checkmates.
 */
 
 {
 static short pnt,tempb,tempc,tempsf,tempst,cnt;
 static struct leaf xnode;
 struct leaf *node;
+short opponent_player = (player == white)?black:white;
 
   *mv = 0;
   if (iop == 2)
     {
-      UnmakeMove(opponent,&xnode,&tempb,&tempc,&tempsf,&tempst);
+      UnmakeMove(player,&xnode,&tempb,&tempc,&tempsf,&tempst);
       return(false);
     }
   cnt = 0;
-  MoveList(opponent,2);
+  MoveList(player,2);
   pnt = TrPnt[2];
   while (pnt < TrPnt[3])
     {
@@ -2264,10 +2267,10 @@ struct leaf *node;
     }
   if (cnt == 1)
     {
-      MakeMove(opponent,&xnode,&tempb,&tempc,&tempsf,&tempst);
-      if (SqAtakd(PieceList[opponent][0],computer))
+      MakeMove(player,&xnode,&tempb,&tempc,&tempsf,&tempst);
+      if (SqAtakd(PieceList[player][0],opponent_player))
         {
-          UnmakeMove(opponent,&xnode,&tempb,&tempc,&tempsf,&tempst);
+          UnmakeMove(player,&xnode,&tempb,&tempc,&tempsf,&tempst);
           /*ShowMessage("Illegal Move!!");*/
           return(false);
         }
@@ -2283,10 +2286,20 @@ struct leaf *node;
           GameList[GameCnt].nodes = 0;
           ElapsedTime(1);
           GameList[GameCnt].time = (short)et;
-          TimeControl.clock[opponent] -= et;
-          --TimeControl.moves[opponent];
+          TimeControl.clock[player] -= et;
+          --TimeControl.moves[player];
           *mv = (xnode.f << 8) + xnode.t;
           algbr(xnode.f,xnode.t,false);
+
+          short index;
+          for (index=0;index<5;index++){
+              move_buffer[index] = mvstr1[index];
+          }
+          if (SqAtakd(PieceList[opponent_player][0],player)){
+              move_buffer[4] = '+';
+              move_buffer[5] = '\0';
+          }
+
           return(true);
         } 
     }
diff --git a/apps/plugins/chessbox/gnuchess.h b/apps/plugins/chessbox/gnuchess.h
index 5367bb3254..6a4a6bdd4e 100644
--- a/apps/plugins/chessbox/gnuchess.h
+++ b/apps/plugins/chessbox/gnuchess.h
@@ -49,7 +49,7 @@ extern struct plugin_api* rb;
 /* ---- The beginning of a GNUChess v2 APIfication ---- */
 void SetTimeControl(void);
 void GNUChess_Initialize(void);
-int  VerifyMove(char s[],short iop,unsigned short *mv);
+int  VerifyMove(short player, char s[],short iop,unsigned short *mv, char *move_buffer);
 int  SelectMove ( short side, short iop , void (*callback)(void), char *move_buffer );
 void InitializeStats ( void );
 void ElapsedTime ( short iop );