feat: notation_move_from_string; feat: actually keep track of who makes the move; bugfix: convert char to int the right way

TODO

@@ -1,2 +1,3 @@
-1. Algebraic notation: notation_move_from_string, notation_move_to_string, documentation
+1. Algebraic notation: notation_move_to_string, documentation
-2. Board: board_is_move_legal, add other piece's moves
+2. Board: board_is_move_legal, add other piece's moves
+3. Chess: output special error message for each type of illegal move so it's clear what went wrong

src/algebraic_notation.c

@@ -17,6 +17,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
 
+#include <stdio.h>
 #include <stddef.h>
 #include <stdlib.h>
 #include <string.h>
@@ -28,42 +29,43 @@ Position notation_tile_to_position(TileNotation notation) {
     Position pos;
     switch (notation.file) {
         case 'a': {
-            pos.column = 1;            
+            pos.column = 0;            
             break;
         }
         case 'b': {
-            pos.column = 2;            
+            pos.column = 1;            
             break;
         }
         case 'c': {
-            pos.column = 3;            
+            pos.column = 2;            
             break;
         }
         case 'd': {
-            pos.column = 4;            
+            pos.column = 3;            
             break;
         }
         case 'e': {
-            pos.column = 5;            
+            pos.column = 4;            
             break;
         }
         case 'f': {
-            pos.column = 6;            
+            pos.column = 5;            
             break;
         }
         case 'g': {
-            pos.column = 7;            
+            pos.column = 6;            
             break;
         }
         case 'h': {
-            pos.column = 8;            
+            pos.column = 7;            
             break;
         }
         default: {
             break;
         }
     }
-    pos.row = notation.rank;
+    // pos.row = notation.rank - 1;
+    pos.row = (8 - (notation.rank));
 
     return pos;
 }
@@ -101,7 +103,7 @@ TileNotation notation_tile_from_string(const char* tile_string) {
 
     TileNotation tile;
     tile.file = tile_string[0];
-    tile.rank = (unsigned int) tile_string[1];
+    tile.rank = (unsigned int) (tile_string[1] - '0'); // Convert to proper int
 
     return tile;
 }
@@ -239,6 +241,28 @@ int notation_is_piece_char(char character) {
 }
 
 
+/*
+Returns a piece deduced from character, returns NONE piece if couldn't deduce a piece type.
+Big characters are for WHITE pieces, small for BLACK pieces.
+*/
+Piece notation_piece_from_char(char character) {
+    if (character == 'K') return piece_new(WHITE, KING);
+    else if (character == 'k') return piece_new(BLACK, KING);
+    else if (character == 'R') return piece_new(WHITE, ROOK);
+    else if (character == 'r') return piece_new(BLACK, ROOK);
+    else if (character == 'B') return piece_new(WHITE, BISHOP);
+    else if (character == 'b') return piece_new(BLACK, BISHOP);
+    else if (character == 'N') return piece_new(WHITE, KNIGHT);
+    else if (character == 'n') return piece_new(BLACK, KNIGHT);
+    else if (character == 'P') return piece_new(WHITE, PAWN);
+    else if (character == 'p') return piece_new(BLACK, PAWN);
+    else if (character == 'Q') return piece_new(WHITE, QUEEN);
+    else if (character == 'q') return piece_new(BLACK, QUEEN);
+
+    return piece_new(WHITE, NONE);
+}
+
+
 char* notation_move_to_string(MoveNotation move) {
     char* move_notation = (char*) malloc(sizeof(char) * 10);
     if (!move_notation) {
@@ -302,8 +326,20 @@ char* notation_move_to_string(MoveNotation move) {
 }
 
 
+/*
+Accepts a move string which consists of an origin square, piece name
+(upper case for WHITE, lower case for BLACK) and a square to move to 
+in algebraic notation.
+
+Returns a notated move with origin, target and piece values set. Move type is to be
+determined by the engine.
+
+Returns NULL if technical errors were encountered, move_string does not contain enough information
+*/
 MoveNotation* notation_move_from_string(const char* move_string) {
-    if (!move_string) {
+    unsigned int len = strlen(move_string);
+
+    if (!move_string || len < 5) {
         return NULL;
     }
 
@@ -312,11 +348,25 @@ MoveNotation* notation_move_from_string(const char* move_string) {
         return NULL;
     }
 
-    // printf();
-    if (notation_is_piece_char(move_string[0])) {
 
+    // Origin tile
+    TileNotation origin = notation_tile_from_string(move_string);
+
+    // Piece
+    Piece piece = notation_piece_from_char(move_string[2]);
+    if (piece.type == NONE) {
+        // No piece information given
+        return NULL;
     }
 
+    // Target tile
+    TileNotation target = notation_tile_from_string(move_string + 3);
+
+    move->origin = origin;
+    move->piece = piece;
+    move->target = target;
+    move->move_type = 0;
+
     return move;
 }
 

src/algebraic_notation.h

@@ -59,6 +59,12 @@ char notation_piece_to_char(Piece piece);
 // Returns 1 if character is one of the piece characters, 0 otherwise
 int notation_is_piece_char(char character);
 
+/*
+Returns a piece deduced from character, returns NONE piece if couldn't deduce a piece type.
+Big characters are for WHITE pieces, small for BLACK pieces.
+*/
+Piece notation_piece_from_char(char character);
+
 
 typedef struct MoveNotation {
     Piece piece;
@@ -71,6 +77,16 @@ typedef struct MoveNotation {
 char* notation_move_to_string(MoveNotation move);
 
 
+/*
+Accepts a move string which consists of an origin square, piece name
+(upper case for WHITE, lower case for BLACK) and a square to move to 
+in algebraic notation.
+
+Returns a notated move with origin, target and piece values set. Move type is to be
+determined by the engine.
+
+Returns NULL if technical errors were encountered, move_string does not contain enough information
+*/
 MoveNotation* notation_move_from_string(const char* move_string);
 
 

src/board.c

@@ -471,26 +471,41 @@ Position* board_get_rook_moves(const Board* board, const Tile* rook_tile, unsign
 
 
 /*
-Checks if a move is legal on this board.
+Checks if a move is legal or not (and reason) on this board.
 
-Returns 1 - if the move is legal, 0 - otherwise
+Returns MoveLegality
 */
-int board_is_move_legal(const Board* board, Move move) {
+MoveLegality board_is_move_legal(const Board* board, Move move, Color color_plays) {
     // Check if the tiles are not out of bounds
     if (!board_is_tile_in_bounds(board, move.origin) || 
         !board_is_tile_in_bounds(board, move.target)
     ) {
         
-        return 0;
+        return ILLOUTOFBOUNDS;
     }
 
     // Check if there is a piece at all
     if (board_get_tile(board, move.origin)->piece.type == NONE) {
-        return 0;
+        return ILLNOPIECE;
     }
 
     Tile* origin_tile = board_get_tile(board, move.origin);
     Tile* target_tile = board_get_tile(board, move.target);
+
+    // Check if the piece is of the player's color
+    if (origin_tile->piece.color != color_plays) {
+        return ILLNOTYOURPIECE;
+    }
+
+    // See if the target tile is of the allied color
+    if (tile_is_occupied(*target_tile)) {
+        // The tile is occupied
+        if (target_tile->piece.color == color_plays) {
+            // The pieces are allied, can't go there!
+            return ILLSAMECOLOR;
+        }
+    }
+
     
     // Check based on the piece type
     Piece origin_piece = origin_tile->piece;    
@@ -498,23 +513,14 @@ int board_is_move_legal(const Board* board, Move move) {
         case KING: {
             if (position_distance(move.origin, move.target) > 1) {
                 // Too far away
-                return 0;
+                return ILLINVALIDPIECEMOVEMENT;
             }
 
-            // See if the target tile is occupied or not
+            return LEGAL;
-            if (tile_is_occupied(*target_tile)) {
-                // The tile is occupied
-                if (target_tile->piece.color == origin_piece.color) {
-                    // The pieces are allied, can't go there
-                    return 0;
-                }
-            }
-
-            return 1;
         }
 
         case QUEEN: {
-            return 1;
+            return LEGAL;
         }
 
         case ROOK: {
@@ -532,49 +538,54 @@ int board_is_move_legal(const Board* board, Move move) {
                 {
                     // This position is allowed to be moved to
                     free(legal_positions);
-                    return 1;
+                    return LEGAL;
                 }
             }
 
             free(legal_positions);
-            return 0;
+            return LEGAL;
         }
 
         case KNIGHT: {
-            return 1;
+            return LEGAL;
         }
 
         case BISHOP: {
-            return 1;
+            return LEGAL;
         }
 
         case PAWN: {
-            return 1;
+            return LEGAL;
         }
 
         default: {
             // Non reachable
-            return 0;
+            return LEGAL;
         }
     }
 }
 
 
 /*
-Moves piece from one place to other, 
+Moves piece from one place to other, does not 
-checking whether it is a legal move or not.
+check if move is legal or not.
 
-Returns 1 if a move has been successfully done,
+Returns 1 if move has been successfully done, 0 - otherwise
-0 - if it is an illegal move
 */ 
-int board_process_move(Board* board, Move move) {
+int board_make_move(Board* board, Move move) {
-    if (!board_is_move_legal(board, move)) {
+    if (!board) {
         return 0;
     }
 
-    // The tiles are legal, no need to re-check
     Tile* tile_origin = board_get_tile(board, move.origin);
+    if (!tile_origin) {
+        return 0;
+    }
+
     Tile* tile_target = board_get_tile(board, move.target);
+    if (!tile_target) {
+        return 0;
+    }
 
     // Move the piece from one tile to another
     tile_target->piece = tile_origin->piece;

src/board.h

@@ -123,21 +123,31 @@ Position* board_get_king_moves(const Board* board, const Tile* king_tile, unsign
 Position* board_get_rook_moves(const Board* board, const Tile* rook_tile, unsigned int* pos_count);
 
 
+// Move legality status
+typedef enum MoveLegality {
+    LEGAL,
+    ILLSAMECOLOR,
+    ILLINVALIDPIECEMOVEMENT,
+    ILLOUTOFBOUNDS,
+    ILLNOPIECE,
+    ILLNOTYOURPIECE
+} MoveLegality;
+
+
 /*
-Checks if a move is legal on this board.
+Checks if a move is legal or not (and reason) on this board.
 
-Returns 1 - if the move is legal, 0 - otherwise
+Returns MoveLegality
 */
-int board_is_move_legal(const Board* board, Move move);
+MoveLegality board_is_move_legal(const Board* board, Move move, Color color_plays);
 
 
 /*
-Moves piece from one place to other, 
+Moves piece from one place to other, does not 
-checking whether it is a legal move or not.
+check if move is legal or not.
 
-Returns 1 if a move has been successfully done,
+Returns 1 if move has been successfully done, 0 - otherwise
-0 - if it is an illegal move
 */ 
-int board_process_move(Board* board, Move move);
+int board_make_move(Board* board, Move move);
 
 #endif

src/chess.c

@@ -37,6 +37,11 @@ Chess* chess_new(Options options) {
     game->turn = WHITE;
     game->state = READY;
     game->options = options;
+    if (options.play_as_white == 1) {
+        game->plays_as = WHITE;
+    } else {
+        game->plays_as = BLACK;
+    }
 
     return game;
 }
@@ -129,23 +134,37 @@ void chess_next_turn(Chess* chess) {
 
     // Keep asking for a legitimate move
     Move* move = NULL;
-    int result = 0;
+    MoveLegality result = 0;
     while (1) {
         // Get a move
         move = chess_take_move_input(chess);
         if (!move) {
-            printf("Invalid move input!\n");
+            printf("Invalid move input! (opt, where o - origin tile, p - piece, t - target tile: a2Pa4 moves white pawn at a2 to a4)\n");
             continue;
         }
         
-        // Make a move
+        printf("(%d %d) --- (%d %d)\n", move->origin.row, move->origin.column, move->target.row, move->target.column);
-        result = board_process_move(chess->board, *move);
+        
-        if (!result) {
+        
+        // Check if it's a valid move
+        result = board_is_move_legal(chess->board, *move, chess->turn);
+        if (result != LEGAL) {
+            // TODO: output special message for each illegal move
+            
             printf("Illegal move!\n");
             free(move);
             continue;
         }
 
+
+        // Make a move!
+        int move_made = board_make_move(chess->board, *move);
+        if (!move_made) {
+            printf("Failed to make a move!\n"); // Should not be reacheable
+            free(move);
+            continue;
+        }
+
         break;
     }
     free(move);

src/chess.h

@@ -37,12 +37,14 @@ typedef struct Options {
     FILE* input;
     FILE* output;
     int use_ansi;
+    int play_as_white;
 } Options;
 
 
 typedef struct Chess {
     Board* board;
     Color turn;
+    Color plays_as;
     unsigned int moves_made;
     unsigned int timer_white_ms;
     unsigned int timer_black_ms;