Refactor

src/chess.c

@@ -0,0 +1,124 @@
+
+#include "common.h"
+#include "graphics.h"
+#include "pieces.h"
+
+#include <ctype.h>  /* isalpha, isdigit ... */
+#include <locale.h> /* setlocale */
+#include <stdio.h>  /* printf, scanf */
+#include <string.h> /* memcpy */
+
+int    do_turn(int turn_no, tile_t board[BOARD_SIZE]);
+void    init_board(tile_t board[BOARD_SIZE]);
+index_t input_to_index(char input[2]);
+
+int main()
+{
+    int turn = 0;
+
+    setlocale(LC_ALL, "C.UTF-8");
+
+    tile_t board[8 * 8] = { 0 };
+
+    init_board(board);
+
+    while (true) {
+        printf("\033[2J"); // clear screen
+        print_board(board);
+
+		// turn increments on valid inputs,
+		// otherwise refreshes screen
+        turn = do_turn(turn, board);
+    }
+
+    return 0;
+}
+
+/**
+ * Resets/initializes the board
+ *
+ * Sets all the tiles of the board to match the starting position of chess.
+ *
+ * \param board Pointer to list of tiles representing board state
+ */
+void init_board(tile_t board[BOARD_SIZE])
+{
+    // black pieces are prefixed by a minus (-)
+    const tile_t start[]
+        = { -R, -N, -B, -Q, -K, -B, -N, -R, -P, -P, -P, -P, -P, -P, -P, -P,
+            E,  E,  E,  E,  E,  E,  E,  E,  E,  E,  E,  E,  E,  E,  E,  E,
+            E,  E,  E,  E,  E,  E,  E,  E,  E,  E,  E,  E,  E,  E,  E,  E,
+            P,  P,  P,  P,  P,  P,  P,  P,  R,  N,  B,  Q,  K,  B,  N,  R };
+
+    memcpy(board, start, sizeof(start));
+}
+
+// TODO: Implement algebaric notation
+/** Asks for move, validates move and does move if valid
+ *
+ * \param turn_no Turn number
+ * \param board   Pointer to list of tiles representing board state
+ *
+ * \return turn+1 if successful, turn+0 if invalid input from player
+ * */
+int do_turn(int turn_no, tile_t board[BOARD_SIZE])
+{
+    char input[3] = { 0 };
+
+    int from = -1, to = -1;
+
+    printf("\nPlayer %i, your turn to move", 1 + turn_no % 2);
+	printf("\nMove piece\nfrom: ");
+
+	scanf(" %2s", input);
+
+	from = input_to_index(input);
+
+	if (from == -1)
+		return turn_no;
+
+	printf("\nto: ");
+	scanf(" %2s", input);
+
+	to = input_to_index(input);
+
+	if (to == -1)
+		return turn_no;
+
+	if (! move_ok(board, from, to, turn_no % 2 ? BLACK : WHITE))
+		return turn_no;
+
+    board[to]   = board[from];
+    board[from] = E;
+
+	/* increment to make it next turn */
+	return turn_no+1;
+}
+
+/**
+ * Translates A1, 3B etc. to the 1D index of the board
+ *
+ *	\param input string of length 2 representing tile, e.g. "A3"
+ *
+ * */
+index_t input_to_index(char input[2])
+{
+    int x = -1, y = -1, c;
+
+    for (int i = 0; i < 2; i++) {
+        c = input[i];
+
+        if (isalpha(c))
+            c = toupper(input[0]);
+
+        if ('A' <= c && c <= 'H')
+            x = c - 'A';
+        else if ('1' <= c && c <= '8')
+            y = c - '1';
+    }
+
+    if (x != -1 && y != -1)
+        return 8 * (7 - y) + x;
+    else
+        return -1;
+}