checkmate

2 files changed, 97 insertions, 47 deletions

diff --git a/chess b/chess
index 8ba4c2c..c473760 100755
--- a/chess
+++ b/chess
diff --git a/chess.c b/chess.c
index ec2dae7..2168b32 100644
--- a/chess.c
+++ b/chess.c
@@ -1,4 +1,4 @@
-// do what the fuck you want
+// TODO: recatoring, debugging and stalemate
 
 #include <arpa/inet.h>
 #include <stdbool.h>
@@ -23,6 +23,7 @@ int abs(int a) {
     return -1 * a;
 }
 
+typedef enum result { r_no, r_win, r_stalemate } result;
 typedef enum piece_type {
   p_no,
   p_pawn = 'P',
@@ -33,6 +34,17 @@ typedef enum piece_type {
   p_king = 'K'
 } piece_type;
 
+typedef struct pos {
+  int x;
+  int y;
+} pos;
+
+typedef struct move {
+  pos f;
+  pos t;
+  piece p;
+} move;
+
 typedef struct piece {
   piece_type p;
   color c;
@@ -44,8 +56,10 @@ 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;
 
-bool is_valid();
+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();
@@ -99,9 +113,13 @@ void print_table() {
 }
 
 bool in_check(color c, int cx, int cy) {
+  printf("c: %d, %d, %d\n", c, 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)) {
+        printf("true check\n");
         return true;
       }
     }
@@ -137,45 +155,54 @@ void setup_table() {
   table[5][0] = (piece){p_bishop, c_w};
   table[6][0] = (piece){p_knight, c_w};
   table[7][0] = (piece){p_rook, c_w};
-  for (int x = 0; x < 8; x++)
-    table[x][1] = (piece){p_pawn, c_w};
+  //  for (int x = 0; x < 8; x++)
+  // table[x][1] = (piece){p_pawn, c_w};
 
-  table[0][7] = (piece){p_rook, c_b};
-  table[1][7] = (piece){p_knight, c_b};
-  table[2][7] = (piece){p_bishop, c_b};
+  // table[0][7] = (piece){p_rook, c_b};
+  // table[1][7] = (piece){p_knight, c_b};
+  // 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[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};
+  // table[4][7] = (piece){p_queen, 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; }
 
-bool is_checkmate(color c) {
+result is_checkmate(color c) {
   int kx = -1, ky = -1;
   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 == c) {
         kx = x;
         ky = y;
+        goto out;
       }
     }
   }
+out:
+  printf("k: %d %d\n", kx, ky);
+  if (kx == -1 || ky == -1)
+    return r_no;
   if (!in_check(c, kx, ky)) {
-    return false;
+    printf("k not in check\n");
+    return r_no;
   }
+  printf("k in check\n");
   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) && !in_check(c, kx + x, ky + y)) {
-        return false;
+      if (is_valid(kx, ky, kx + x, ky + y) && 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;
   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)) {
@@ -186,14 +213,13 @@ bool is_checkmate(color c) {
           int v_y = dy ? ((dy > 0) ? 1 : -1) : 0;
           for (int n = 1; n < abs(dx); n++)
             if (table[x + n * v_x][y + n * v_y].p == p_no)
-              if (in_check(!c, x + n * v_x, y + n * v_y))
-                return false;
-        } else if (table[x][y].p == p_rook) {
+              if (in_check(ic, x + n * v_x, y + n * v_y))
+                return r_no;
         }
       }
     }
   }
-  return true;
+  return r_win;
 }
 
 bool is_valid(int from_x, int from_y, int to_x, int to_y) {
@@ -201,13 +227,13 @@ bool is_valid(int from_x, int from_y, int to_x, int to_y) {
   int dx = to_x - from_x, dy = to_y - from_y;
   int v_x, v_y, l;
   if (in_check_sim(from_x, from_y, to_x, to_y))
-    return 0;
+    return false;
   switch (p.p) {
   case p_pawn:
-    // TODO: refactor, en passant
     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)) ||
+          (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) ||
         (dy == 2 &&
          (p.c != c_w || from_y != 1 || table[from_x][from_y + 1].p != p_no)) ||
@@ -247,7 +273,7 @@ bool is_valid(int from_x, int from_y, int to_x, int to_y) {
     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)
-        return 0;
+        return false;
     break;
   case p_king:
     if (in_check(p.c, to_x, to_y))
@@ -291,8 +317,30 @@ 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 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;
+    }
+  }
+}
+
 void play_game() {
-  color c_c = c_w;
+  color c_c = c_w; // current color
   for (;;) {
     print_table();
     if (c_c == c_w)
@@ -301,8 +349,13 @@ void play_game() {
       dprintf(w_fd, "fekete gondolkodik...\n");
   no_print:
     dprintf(*c_fd, "> ");
+    print_result(c_c);
+
+    // parse move
     char buf[50] = {0};
-    read(*c_fd, buf, 20);
+    read(*c_fd, buf, 50);
+    if (buf[0] == 's')
+      goto skip;
     if (buf[0] == ':') {
       if (c_c == c_w)
         dprintf(b_fd, buf);
@@ -314,13 +367,8 @@ void play_game() {
     int from_y = buf[1] - '1';
     int to_x = buf[3] - 'a';
     int to_y = buf[4] - '1';
-    if (is_checkmate(c_c)) {
-      if (c_c == c_w)
-        PRINT_ALL("a fekete nyert!");
-      else
-        PRINT_ALL("a fehér nyert!");
-      break;
-    }
+
+    // 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 ||
@@ -329,20 +377,21 @@ void play_game() {
       dprintf(*c_fd, "hiba: %d %d %d %d\n", from_x, from_y, to_x, to_y);
       goto no_print;
     } else {
-      printf("%s", buf);
-      if (c_c == c_w)
-        dprintf(b_fd, buf);
-      else
-        dprintf(w_fd, buf);
-      if (table[to_x][to_y].p == p_king) {
-        if (c_c == c_w)
-          PRINT_ALL("a fehér nyert!");
-        else
-          PRINT_ALL("a fekete nyert!");
-        break;
-      }
+      print_move(c_c, buf);
+
+      // do move
       table[to_x][to_y] = table[from_x][from_y];
-      table[from_x][from_y] = (piece){p_no, c_w};
+      table[from_x][from_y].p = p_no;
+
+      // 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;
+
+      // trade pawn
       if ((to_y == 0 || to_y == 7) && table[to_x][to_y].p == p_pawn) {
         char cbuf[10] = {0};
       retry:
@@ -373,6 +422,7 @@ void play_game() {
         }
       }
     }
+  skip:
     if (c_fd == &w_fd) {
       c_fd = &b_fd;
       c_c = c_b;