refactoring

2 files changed, 205 insertions, 139 deletions

diff --git a/chess b/chess
new file mode 100755
index 0000000..243e72d
--- /dev/null
+++ b/chess
diff --git a/sakkom.c b/sakkom.c
index 430ce8d..3e8e8c3 100644
--- a/sakkom.c
+++ b/sakkom.c
@@ -45,31 +45,52 @@ typedef struct pos {
   int y;
 } pos;
 
-typedef struct move {
-  pos f;
-  pos t;
-  piece p;
-} move;
-
 typedef struct piece {
   piece_type p;
   color c;
 } piece;
 
+typedef struct move {
+  pos f;   // from
+  pos t;   // to
+  piece p; // piece moved
+  piece e; // enemy taken
+} move;
+
+typedef struct en_passant {
+  bool valid;
+  pos p;
+  piece *to_remove;
+} en_passant;
+en_passant enp;
+
 piece table[8][8];
 int w_fd = -1, b_fd = -1;
 int *c_fd = &w_fd; // current fd
 bool moved_king[2] = {false, false};
 bool moved_rook_l[2] = {false, false};
 bool moved_rook_r[2] = {false, false};
-int pawnx = -1, pawny = -1;
 
+void do_move(move m);
+bool is_move_legal(color c, move m);
 bool in_check(color c, int cx, int cy);
-bool is_valid(int from_x, int from_y, int to_x, int to_y);
 void print_table();
 void setup_table();
 void play_game();
 
+bool is_same_pos(pos p1, pos p2) { return p1.x == p2.x && p1.y == p2.y; }
+
+bool is_empty(piece p) { return p.p == p_no; }
+bool is_friend_of(color c, piece p) { return !is_empty(p) && p.c == c; }
+bool is_enemy_of(color c, piece p) { return !is_empty(p) && p.c != c; }
+
+bool is_inside(int i) { return i >= 0 && i < 8; }
+
+bool is_move_inside(move m) {
+  return is_inside(m.f.x) && is_inside(m.f.y) && is_inside(m.t.x) &&
+         is_inside(m.t.y);
+}
+
 void print_table() {
   dprintf(w_fd, "\n                \e[43m\x1B[30m\033[1m BLACK \x1B[0m\n\n   ");
   dprintf(b_fd, "\n                \e[43m\x1B[39m\033[1m WHITE \x1B[0m\n\n   ");
@@ -120,11 +141,18 @@ void print_table() {
 
 bool in_check(color c, int cx, int cy) {
   printf("c: %d, %d, %d\n", c, cx, cy);
+  move m;
+  m.t.x = cx;
+  m.t.y = cy;
+  m.e = table[cx][cy];
   for (int y = 0; y < 8; y++) {
     for (int x = 0; x < 8; x++) {
       if (cx == x && cy == y)
         continue;
-      if (table[x][y].c != c && is_valid(x, y, cx, cy)) {
+      m.f.x = x;
+      m.f.y = y;
+      m.p = table[x][y];
+      if (table[x][y].c != c && is_move_legal(m.p.c, m)) {
         printf("true check\n");
         return true;
       }
@@ -133,22 +161,20 @@ bool in_check(color c, int cx, int cy) {
   return false;
 }
 
-bool in_check_sim(int from_x, int from_y, int to_x, int to_y) {
-  piece tmp = table[to_x][to_y];
-  table[to_x][to_y] = table[from_x][from_y];
-  table[from_x][from_y].p = p_no;
+bool in_check_sim(move m) {
+  do_move(m);
   bool res = false;
   for (int y = 0; y < 8; y++) {
     for (int x = 0; x < 8; x++) {
-      if (table[x][y].p == p_king && table[x][y].c == table[to_x][to_y].c) {
+      if (table[x][y].p == p_king && table[x][y].c == m.p.c) {
         res = in_check(table[x][y].c, x, y);
-        goto finish;
+        goto out;
       }
     }
   }
-finish:
-  table[from_x][from_y] = table[to_x][to_y];
-  table[to_x][to_y] = tmp;
+out:
+  table[m.f.x][m.f.y] = m.p;
+  table[m.t.x][m.t.y] = m.e;
   return res;
 }
 
@@ -169,15 +195,13 @@ void setup_table() {
   // table[2][7] = (piece){p_bishop, c_b};
   table[3][7] = (piece){p_king, c_b};
   // table[4][7] = (piece){p_queen, c_b};
-  // table[5][7] = (piece){p_bishop, c_b};
+  table[5][7] = (piece){p_bishop, c_b};
   // table[6][7] = (piece){p_knight, c_b};
   // table[7][7] = (piece){p_rook, c_b};
   // for (int x = 0; x < 8; x++)
   // table[x][6] = (piece){p_pawn, c_b};
 }
 
-int is_inside(int i) { return i >= 0 && i < 8; }
-
 result is_checkmate(color c) {
   int kx = -1, ky = -1;
   for (int y = 0; y < 8; y++) {
@@ -198,55 +222,125 @@ out:
     return r_no;
   }
   printf("k in check\n");
+  move m;
+  m.f.x = kx;
+  m.f.y = ky;
+  m.p = table[kx][ky];
   for (int y = -1; y <= 1; y++) {
     for (int x = -1; x <= 1; x++) {
       if (x == 0 && y == 0)
         continue;
-      if (is_valid(kx, ky, kx + x, ky + y) && is_inside(ky + y) &&
-          is_inside(kx + x) && !in_check(c, kx + x, ky + y)) {
+      m.t.x = kx + x;
+      m.t.y = ky + y;
+      m.e = table[kx + x][ky + y];
+      if (is_move_legal(c, m) && is_inside(ky + y) && is_inside(kx + x) &&
+          !in_check(c, kx + x, ky + y)) {
         return r_no;
       }
     }
   }
   color ic = c == c_w ? c_b : c_w;
+  m.t.x = kx;
+  m.t.y = ky;
+  m.e = table[kx][ky];
   for (int y = 0; y < 8; y++) {
     for (int x = 0; x < 8; x++) {
-      if (table[x][y].c != c && is_valid(x, y, kx, ky)) {
+      m.f.x = x;
+      m.f.y = y;
+      m.p = table[x][y];
+      if (table[x][y].c != c && is_move_legal(c, m)) {
         int dx = kx - x, dy = ky - y;
         if (table[x][y].p == p_rook || table[x][y].p == p_queen ||
             table[x][y].p == p_bishop) {
           int v_x = dx ? ((dx > 0) ? 1 : -1) : 0;
           int v_y = dy ? ((dy > 0) ? 1 : -1) : 0;
-          for (int n = 1; n < abs(dx); n++)
+          bool possible = false;
+          for (int n = 0; n < abs(dx); n++)
             if (table[x + n * v_x][y + n * v_y].p == p_no)
               if (in_check(ic, x + n * v_x, y + n * v_y))
-                return r_no;
+                possible = true;
+          if (!possible) {
+            return r_win;
+          }
         }
+        return r_no;
       }
     }
   }
   return r_win;
 }
 
-bool is_valid(int from_x, int from_y, int to_x, int to_y) {
-  piece p = table[from_x][from_y];
-  int dx = to_x - from_x, dy = to_y - from_y;
+void print_move(move m) {
+  char buf[20];
+  int n = 0;
+  buf[n++] = table[m.f.x][m.f.y].p;
+  buf[n++] = m.f.x + 'a';
+  buf[n++] = m.f.y + '0';
+  buf[n++] = ' ';
+  if (table[m.t.x][m.t.y].p != p_no)
+    buf[n++] = table[m.t.x][m.t.y].p;
+  buf[n++] = m.t.x + 'a';
+  buf[n++] = m.t.y + '0';
+  buf[n++] = '\n';
+  buf[n++] = '\0';
+  printf("%s", buf);
+  if (m.p.c == c_w)
+    dprintf(b_fd, buf);
+  else
+    dprintf(w_fd, buf);
+}
+
+bool print_result(color c) {
+  result r;
+  if ((r = is_checkmate(c)) != r_no) {
+    if (r == r_stalemate) {
+      PRINT_ALL("\ndöntetlen\n");
+    } else {
+      if (c == c_w)
+        PRINT_ALL("\na fekete nyert!\n");
+      else
+        PRINT_ALL("\na fehér nyert!\n");
+    }
+    return true;
+  }
+  return false;
+}
+
+move parse_move(char buf[50]) {
+  move m;
+
+  m.f.x = buf[0] - 'a';
+  m.f.y = buf[1] - '1';
+  m.t.x = buf[3] - 'a';
+  m.t.y = buf[4] - '1';
+
+  m.p = table[m.f.x][m.f.y];
+  m.e = table[m.t.x][m.t.y];
+
+  return m;
+}
+
+bool is_move_legal(color c, move m) {
+  if (!is_move_inside(m) || is_empty(m.p) || is_enemy_of(c, m.p) ||
+      is_friend_of(c, m.e))
+    return false;
+
+  int dx = m.t.x - m.f.x, dy = m.t.y - m.f.y;
   int v_x, v_y, l;
-  if (in_check_sim(from_x, from_y, to_x, to_y))
+  if (in_check_sim(m))
     return false;
-  switch (p.p) {
+  switch (m.p.p) {
   case p_pawn:
-    if ((dx != 0 &&
-         ((dx != 1 && dx != -1) || (dy != 1 && p.c == c_w) ||
-          (dy != -1 && p.c == c_b) ||
-          (table[to_x][to_y].p == p_no && to_x != pawnx && to_y != pawny))) ||
-        dy < -2 || dy > 2 || (dy == 1 && p.c != c_w) ||
+    if ((dx != 0 && ((dx != 1 && dx != -1) || (dy != 1 && c == c_w) ||
+                     (dy != -1 && c == c_b) ||
+                     (is_empty(m.e) && is_same_pos(m.t, enp.p)))) ||
+        dy < -2 || dy > 2 || (dy == 1 && c != c_w) ||
         (dy == 2 &&
-         (p.c != c_w || from_y != 1 || table[from_x][from_y + 1].p != p_no)) ||
-        (dy == -1 && p.c != c_b) ||
+         (c != c_w || m.f.y != 1 || table[m.f.x][m.f.y + 1].p != p_no)) ||
+        (dy == -1 && c != c_b) ||
         (dy == -2 &&
-         (p.c != c_b || from_y != 6 || table[from_x][from_y - 1].p != p_no)) ||
-        (dx == 0 && table[to_x][to_y].p != p_no))
+         (c != c_b || m.f.y != 6 || table[m.f.x][m.f.y - 1].p != p_no)) ||
+        (dx == 0 && !is_empty(m.e)))
       return false;
     break;
   case p_rook:
@@ -255,12 +349,12 @@ bool is_valid(int from_x, int from_y, int to_x, int to_y) {
     v_x = (dx != 0) ? ((dx > 0) ? 1 : -1) : 0;
     v_y = (dy != 0) ? ((dy > 0) ? 1 : -1) : 0;
     for (int n = 1; n < abs(dx + dy); n++)
-      if (table[from_x + n * v_x][from_y + n * v_y].p != p_no)
+      if (!is_empty(table[m.f.x + n * v_x][m.f.y + n * v_y]))
         return false;
-    if ((from_x == 7 && from_y == 0) || (from_x == 7 && from_y == 7))
-      moved_rook_r[p.c] = true;
-    if ((from_x == 0 && from_y == 0) || (from_x == 0 && from_y == 7))
-      moved_rook_l[p.c] = true;
+    if ((m.f.x == 7 && m.f.y == 0) || (m.f.x == 7 && m.f.y == 7))
+      moved_rook_r[c] = true;
+    if ((m.f.x == 0 && m.f.y == 0) || (m.f.x == 0 && m.f.y == 7))
+      moved_rook_l[c] = true;
     break;
   case p_bishop:
     if (abs(dx) != abs(dy))
@@ -268,7 +362,7 @@ bool is_valid(int from_x, int from_y, int to_x, int to_y) {
     v_x = dx ? ((dx > 0) ? 1 : -1) : 0;
     v_y = dy ? ((dy > 0) ? 1 : -1) : 0;
     for (int n = 1; n < abs(dx); n++)
-      if (table[from_x + n * v_x][from_y + n * v_y].p != p_no)
+      if (!is_empty(table[m.f.x + n * v_x][m.f.y + n * v_y]))
         return false;
     break;
   case p_queen:
@@ -278,39 +372,37 @@ bool is_valid(int from_x, int from_y, int to_x, int to_y) {
     v_y = dy ? ((dy > 0) ? 1 : -1) : 0;
     l = (dx * dy == 0) ? abs(dx + dy) : abs(dx);
     for (int n = 1; n < l; n++)
-      if (table[from_x + n * v_x][from_y + n * v_y].p != p_no)
+      if (!is_empty(table[m.f.x + n * v_x][m.f.y + n * v_y]))
         return false;
     break;
   case p_king:
-    if (in_check(p.c, to_x, to_y))
+    if (in_check(c, m.t.x, m.t.y))
       return 0;
     if (abs(dx) > 1 || abs(dy) > 1) {
-      if (!moved_king[p.c] && dy == 0) {
-        if (!moved_rook_l[p.c] && dx == -2 &&
-            table[from_x - 1][from_y].p == p_no &&
-            table[from_x - 3][from_y].p == p_rook &&
-            table[from_x - 3][from_y].c == p.c &&
-            !in_check(p.c, from_x - 1, from_y) &&
-            !in_check(p.c, from_x, from_y)) {
-          table[from_x - 1][from_y] = table[from_x - 3][from_y];
-          table[from_x - 3][from_y].p = p_no;
+      if (!moved_king[c] && dy == 0) {
+        if (!moved_rook_l[c] && dx == -2 && table[m.f.x - 1][m.f.y].p == p_no &&
+            table[m.f.x - 3][m.f.y].p == p_rook &&
+            table[m.f.x - 3][m.f.y].c == c && !in_check(c, m.f.x - 1, m.f.y) &&
+            !in_check(c, m.f.x, m.f.y)) {
+          table[m.f.x - 1][m.f.y] = table[m.f.x - 3][m.f.y];
+          table[m.f.x - 3][m.f.y].p = p_no;
           break;
-        } else if (!moved_rook_r[p.c] && dx == 3 &&
-                   table[from_x + 1][from_y].p == p_no &&
-                   table[from_x + 2][from_y].p == p_no &&
-                   table[from_x + 4][from_y].p == p_rook &&
-                   table[from_x + 4][from_y].c == p.c &&
-                   !in_check(p.c, from_x + 1, from_y) &&
-                   !in_check(p.c, from_x + 2, from_y) &&
-                   !in_check(p.c, from_x, from_y)) {
-          table[from_x + 2][from_y] = table[from_x + 4][from_y];
-          table[from_x + 4][from_y].p = p_no;
+        } else if (!moved_rook_r[c] && dx == 3 &&
+                   table[m.f.x + 1][m.f.y].p == p_no &&
+                   table[m.f.x + 2][m.f.y].p == p_no &&
+                   table[m.f.x + 4][m.f.y].p == p_rook &&
+                   table[m.f.x + 4][m.f.y].c == c &&
+                   !in_check(c, m.f.x + 1, m.f.y) &&
+                   !in_check(c, m.f.x + 2, m.f.y) &&
+                   !in_check(c, m.f.x, m.f.y)) {
+          table[m.f.x + 2][m.f.y] = table[m.f.x + 4][m.f.y];
+          table[m.f.x + 4][m.f.y].p = p_no;
           break;
         }
       }
       return false;
     }
-    moved_king[p.c] = true;
+    moved_king[c] = true;
     break;
   case p_knight:
     if (!((abs(dx) == 2 && abs(dy) == 1) || (abs(dx) == 1 && abs(dy) == 2)))
@@ -323,24 +415,30 @@ bool is_valid(int from_x, int from_y, int to_x, int to_y) {
   return true;
 }
 
-void print_move(color c, char buf[50]) {
-  printf("%s", buf);
-  if (c == c_w)
-    dprintf(b_fd, buf);
-  else
-    dprintf(w_fd, buf);
+void do_move(move m) {
+  table[m.t.x][m.t.y] = table[m.f.x][m.f.y];
+  table[m.f.x][m.f.y].p = p_no;
 }
 
-void print_result(color c) {
-  if ((result r = is_checkmate(c)) != r_no) {
-    if (r == r_stalemate) {
-      PRINT_ALL("\ndöntetlen\n");
-    } else {
-      if (c == c_w)
-        PRINT_ALL("\na fekete nyert!\n");
-      else
-        PRINT_ALL("\na fehér nyert!\n");
-      break;
+piece_type choose_type(int fd) {
+  char cbuf[10] = {0};
+  while (true) {
+    dprintf(fd, "mit kérsz?\n");
+    dprintf(fd, "> ");
+    read(fd, cbuf, 10);
+    switch (cbuf[0]) {
+    case 'P':
+      return p_pawn;
+    case 'R':
+      return p_rook;
+    case 'N':
+      return p_knight;
+    case 'B':
+      return p_bishop;
+    case 'Q':
+      return p_queen;
+    case 'K':
+      return p_king;
     }
   }
 }
@@ -355,9 +453,10 @@ void play_game() {
       dprintf(w_fd, "fekete gondolkodik...\n");
   no_print:
     dprintf(*c_fd, "> ");
-    print_result(c_c);
+    if (print_result(c_c)) {
+      break;
+    }
 
-    // parse move
     char buf[50] = {0};
     read(*c_fd, buf, 50);
     if (buf[0] == 's')
@@ -369,64 +468,31 @@ void play_game() {
         dprintf(w_fd, buf);
       goto no_print;
     }
-    int from_x = buf[0] - 'a';
-    int from_y = buf[1] - '1';
-    int to_x = buf[3] - 'a';
-    int to_y = buf[4] - '1';
-
-    // is legal
-    if (!is_inside(from_x) || !is_inside(from_y) || !is_inside(to_x) ||
-        !is_inside(to_y) || table[from_x][from_y].p == p_no ||
-        table[from_x][from_y].c != c_c ||
-        (table[to_x][to_y].c == c_c && table[to_x][to_y].p != p_no) ||
-        !is_valid(from_x, from_y, to_x, to_y)) {
-      dprintf(*c_fd, "hiba: %d %d %d %d\n", from_x, from_y, to_x, to_y);
-      goto no_print;
-    } else {
-      print_move(c_c, buf);
 
-      // do move
-      table[to_x][to_y] = table[from_x][from_y];
-      table[from_x][from_y].p = p_no;
+    move m = parse_move(buf);
+
+    if (is_move_legal(c_c, m)) {
+      print_move(m);
+      do_move(m);
 
       // en passant
-      if (to_x == pawnx && to_y == pawny && table[to_x][to_y].p == p_pawn)
-        table[pawnx][to_y + (pawny - to_y)].p = p_no;
-      pawnx = -1, pawny = -1;
-      if (table[to_x][to_y].p == p_pawn &&
-          (from_y - to_y == -2 || from_y - to_y == 2))
-        pawnx = to_x, pawny = to_y + (from_y - to_y) / 2;
+      if (enp.valid && is_same_pos(enp.p, m.t) && m.p.p == p_pawn)
+        enp.to_remove->p = p_no;
+      enp.valid = false;
+      if (m.p.p == p_pawn && abs(m.f.y - m.t.y) == 2) {
+        enp.valid = true;
+        enp.to_remove = &table[m.t.x][m.t.y];
+        enp.p.x = m.t.x;
+        enp.p.y = m.t.y + (c_c == c_w ? -1 : 1);
+      }
 
       // trade pawn
-      if ((to_y == 0 || to_y == 7) && table[to_x][to_y].p == p_pawn) {
-        char cbuf[10] = {0};
-      retry:
-        dprintf(*c_fd, "mit kérsz?\n");
-        dprintf(*c_fd, "> ");
-        read(*c_fd, cbuf, 10);
-        switch (cbuf[0]) {
-        case 'P':
-          table[to_x][to_y].p = p_pawn;
-          break;
-        case 'R':
-          table[to_x][to_y].p = p_rook;
-          break;
-        case 'N':
-          table[to_x][to_y].p = p_knight;
-          break;
-        case 'B':
-          table[to_x][to_y].p = p_bishop;
-          break;
-        case 'Q':
-          table[to_x][to_y].p = p_queen;
-          break;
-        case 'K':
-          table[to_x][to_y].p = p_king;
-          break;
-        default:
-          goto retry;
-        }
-      }
+      if ((m.t.y == 0 || m.t.y == 7) && m.p.p == p_pawn)
+        table[m.t.x][m.t.y].p = choose_type(*c_fd);
+
+    } else {
+      dprintf(*c_fd, "hiba\n");
+      goto no_print;
     }
   skip:
     if (c_fd == &w_fd) {