use coordinates

3 files changed, 173 insertions, 65 deletions

diff --git a/lib/board.c b/lib/board.c
index c4a4f2d..774bfd5 100644
--- a/lib/board.c
+++ b/lib/board.c
@@ -2,6 +2,7 @@
 #include <stdio.h>
 
 #include "board.h"
+#include "coordinate.h"
 #include "piece.h"
 
 static Board _setup_colors(Board b) {
@@ -9,69 +10,78 @@ static Board _setup_colors(Board b) {
     
     for (i = 0; i < SIZE; i++)
         for (j = 0; j < SIZE; j++)
-            if (i % 2) // Odd rows start with white
+            if (i % 2)
                 if (j % 2)
-                    b[i][j].color = WHITE;
-                else
                     b[i][j].color = BLACK;
+                else
+                    b[i][j].color = WHITE;
             else
                 if (j % 2)
-                    b[i][j].color = BLACK;
-                else
                     b[i][j].color = WHITE;
+                else
+                    b[i][j].color = BLACK;
 
     return b;
 }
 
+static Board _set_new_piece(Board b, Coord c, Color color, PieceType t) {
+    Square s = board_get_square(b, c);
+    s.piece = new_piece(color, t);
+
+    return board_set_square(b, c, s);
+}
+
 static Board _pawns(Board b) {
-    short white_pawns_row = 1, black_pawns_row = 6, i;
+    Coord c = coord_set_row(coord_null(), '2');
+    char col;
 
-    for (i = 0; i < SIZE; i++)
-        b[white_pawns_row][i].piece = new_piece(WHITE, PAWN);
+    for (col = 'a'; col <= 'h'; col++)
+        _set_new_piece(b, coord_set_col(c, col), WHITE, PAWN);
 
-    for (i = 0; i < SIZE; i++)
-        b[black_pawns_row][i].piece = new_piece(BLACK, PAWN);
+    c = coord_set_row(coord_null(), '7');
+    for (col = 'a'; col <= 'h'; col++)
+        _set_new_piece(b, coord_set_col(c, col), BLACK, PAWN);
 
     return b;
 }
 
 static Board _rocks(Board b) {
-    b[0][0].piece = new_piece(WHITE, ROCK);
-    b[0][7].piece = new_piece(WHITE, ROCK);
-    b[7][0].piece = new_piece(BLACK, ROCK);
-    b[7][7].piece = new_piece(BLACK, ROCK);
+    _set_new_piece(b, coord_init("a1"), WHITE, ROCK);
+    _set_new_piece(b, coord_init("h1"), WHITE, ROCK);
+    _set_new_piece(b, coord_init("a8"), BLACK, ROCK);
+    _set_new_piece(b, coord_init("h8"), BLACK, ROCK);
 
     return b;
 }
 
 static Board _knights(Board b) {
-    b[0][1].piece = new_piece(WHITE, KNIGHT);
-    b[0][6].piece = new_piece(WHITE, KNIGHT);
-    b[7][1].piece = new_piece(BLACK, KNIGHT);
-    b[7][6].piece = new_piece(BLACK, KNIGHT);
+    _set_new_piece(b, coord_init("b1"), WHITE, KNIGHT);
+    _set_new_piece(b, coord_init("g1"), WHITE, KNIGHT);
+    _set_new_piece(b, coord_init("b8"), BLACK, KNIGHT);
+    _set_new_piece(b, coord_init("g8"), BLACK, KNIGHT);
 
     return b;
 }
 
 static Board _bishops(Board b) {
-    b[0][2].piece = new_piece(WHITE, BISHOP);
-    b[0][5].piece = new_piece(WHITE, BISHOP);
-    b[7][2].piece = new_piece(BLACK, BISHOP);
-    b[7][5].piece = new_piece(BLACK, BISHOP);
+    _set_new_piece(b, coord_init("c1"), WHITE, BISHOP);
+    _set_new_piece(b, coord_init("f1"), WHITE, BISHOP);
+    _set_new_piece(b, coord_init("c8"), BLACK, BISHOP);
+    _set_new_piece(b, coord_init("f8"), BLACK, BISHOP);
 
     return b;
 }
 
 static Board _queens(Board b) {
-    b[0][4].piece = new_piece(WHITE, QUEEN);
-    b[7][4].piece = new_piece(BLACK, QUEEN);
+    _set_new_piece(b, coord_init("d1"), WHITE, QUEEN);
+    _set_new_piece(b, coord_init("d8"), BLACK, QUEEN);
 
     return b;
 }
 
 static Board _kings(Board b) {
-    b[0][3].piece = new_piece(WHITE, KING);
-    b[7][3].piece = new_piece(BLACK, KING);
+    _set_new_piece(b, coord_init("e1"), WHITE, KING);
+    _set_new_piece(b, coord_init("e8"), BLACK, KING);
 
     return b;
 }
diff --git a/lib/coordinate.c b/lib/coordinate.c
index 2dc0215..7518a78 100644
--- a/lib/coordinate.c
+++ b/lib/coordinate.c
@@ -3,29 +3,110 @@
 
 #include "coordinate.h"
 
-static int _valid_coord(char col, char row) {
+/*
+ * Returns 0 if the coordinate is between a1 and h8.
+ */
+int coord_is_valid(char *s) {
+    if (strnlen(s, 3) != 2)
+        return 1;
+
+    char col = tolower(s[0]);
+    char row = tolower(s[1]);
+
     if (col >= 'a' && col <= 'h' && row >= '1' && row <= '8')
         return 0;
 
-    return 1;
+    return 2;
 }
 
-int coord_init(Coord* c, char col, char row) {
-    char lower_col = tolower(col);
-    char lower_row = tolower(row);
+/*
+ * Does not check if s is a valid string representing. If input is
+ * untrusted, use coord_is_valid(char*) to check it.
+ */
+Coord coord_init(char* s) {
+    Coord c;
+    char col = tolower(s[0]);
+    char row = tolower(s[1]);
 
-    if (! _valid_coord(lower_col, lower_row))
-        return 1;
+    c.col = col;
+    c.row = row;
+
+    return c;
+}
+
+/*
+ * Returns 0 if c is the null coordinate
+ */
+int coord_is_null(Coord c) {
+    return (c.col == 0 && c.row == 0);
+}
 
-    c->row = row;
-    c->col = col;
+/*
+ * Returns the null coordinate
+ */
+Coord coord_null() {
+    Coord c;
 
-    return 0;        
+    c.col = 0;
+    c.row = 0;
+
+    return c;
 }
 
-int coord_init_from_str(Coord* c, char* s) {
-    if (strlen(s) != 2)
-        return 1;
+/*
+ * Set Coord row
+ */
+Coord coord_set_row(Coord c, char row) {
+    c.row = row;
+
+    return c;
+}
+
+/*
+ * Set Coord column
+ */
+Coord coord_set_col(Coord c, char col) {
+    c.col = col;
+
+    return c;
+}
+
+/*
+ * Returns the next coordinate. Useful for traversing the board forwards.
+ */
+Coord coord_next(Coord c) {
+    if (coord_is_null(c))
+        c = coord_init("a8");
+    else
+        if (c.col == 'h')
+            if (c.row == '1')
+                c = coord_null();
+            else {
+                c.row -= 1;
+                c.col = 'a';
+            }
+        else
+            c.col += 1;
+
+    return c;
+}
+
+/*
+ * Returns the previous coordinate. Useful for traversing the board backwards.
+ */
+Coord coord_prev(Coord c) {
+    if (coord_is_null(c))
+        c = coord_init("h1");
+    else
+        if (c.col == 'a')
+            if (c.row == '8')
+                c = coord_null();
+            else {
+                c.row += 1;
+                c.col = 'h';
+            }
+        else
+            c.col -= 1;
 
-    return coord_init(c, s[0], s[1]);
+    return c;
 }
diff --git a/lib/print.c b/lib/print.c
index 249e486..9282581 100644
--- a/lib/print.c
+++ b/lib/print.c
@@ -2,8 +2,26 @@
 #include <stdlib.h>
 
 #include "print.h"
+#include "board.h"
+#include "coordinate.h"
 #include "piece.h"
 
+static void _print_row_separator() {
+    int j;
+
+    for (j = 0; j < SIZE; j++)
+        printf("+---");
+
+    printf("+\n");
+}
+
+static Coord _next_coord(Coord c, Color side)  {
+        if (side == WHITE)
+            return coord_next(c);
+        else
+            return coord_prev(c);
+}
+
 /* Printing related functions */
 void print_piece(Piece p) {
     putchar(piece_character(p));
@@ -11,39 +29,38 @@ void print_piece(Piece p) {
 
 void print_square(Square s) {
     if (s.piece == NULL)
-        switch (s.color) {
-        case WHITE:
+        if (s.color == WHITE)
             putchar(' ');
-            break;;
-        case BLACK:
+        else
             putchar('/');
-            break;
-        default:
-            perror("Wait... what?\n");
-            exit(EXIT_FAILURE);
-        }
     else
         print_piece(*s.piece);
 }
 
-void print_board(Board b) {
-    int i, j;
+/*
+ * Pretty print the board. The "side" parameter lets you choose the
+ * orientation. Use WHITE for a white player perspective, BLACK otherwise.
+ */
+void print_board(Board b, Color side) {
+    Coord c = _next_coord(coord_null(), side);
+    char current_row = c.row;
 
-    for (i = 0; i < SIZE; i++) {
-        for (j = 0; j < SIZE; j++)
-            printf("+---");
-        printf("+\n");
+    _print_row_separator();
+    while (!coord_is_null(c)) {
+        // Print the square
+        printf("| ");
+        print_square(board_get_square(b, c));
+        putchar(' ');
 
-        for (j = 0; j < SIZE; j++) {
-            printf("| ");
-            print_square(b[i][j]);
-            putchar(' ');
-        }
-        printf("|\n");
-    }
+        // Shall we move forward or backwards?
+        c = _next_coord(c, side);
 
-    for (j = 0; j < SIZE; j++)
-        printf("+---");
-    printf("+\n");
+        // If the row changed then we must start a new line
+        if (c.row != current_row) {
+            printf("|\n");
+            _print_row_separator();
 
+            current_row = c.row;
+        }
+    }
 }