imprograming fen parser

2 files changed, 110 insertions, 48 deletions

diff --git a/src/board.cpp b/src/board.cpp
index 1085dbb..d15f4b9 100644
--- a/src/board.cpp
+++ b/src/board.cpp
@@ -1,6 +1,8 @@
 #include "board.hpp"
 #include <cctype>
 #include <cstdio>
+#include <iostream>
+#include <print>
 #include <string>
 
 bool WHITE = true;
@@ -22,65 +24,125 @@ void printBoard(board *b) {
       std::printf("\n");
     }
   }
+  std::printf("%d to play\n", b->turn);
+  std::cout << "castle: " << b->castle << "\n";
 }
 void setBoardFen(std::string fen, board *b) {
   // example fen rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
   int file = 0;
   int rank = 0;
 
+  std::string castle = "";
+
+  enum parserState {
+    POSITION,
+    TURN,
+    CASTLE,
+    ENPASSANT,
+    CLOCK1,
+    CLOCK2,
+  };
+  parserState state = POSITION;
+
   for (int i = 0; i < fen.length(); i++) {
-    if (fen[i] == '/') {
-      file = 0;
-      rank++;
-      continue;
-    }
-    if (isdigit(fen[i])) {
-      int move = fen[i] - '0';
-      file += move;
+    std::printf("state: %d\n", state);
+    std::printf("doing: %c\n", fen[i]);
+    if (fen[i] == ' ') {
+      if (state == POSITION) {
+        state = TURN;
+        continue;
+      }
+      if (state == TURN) {
+        state = CASTLE;
+        continue;
+      }
+      if (state == CASTLE) {
+        state = ENPASSANT;
+        continue;
+      }
       continue;
     }
-    if (toupper(fen[i]) == 'W') {
-      b->turn = WHITE;
+    if (state == CASTLE) {
+      if (fen[i] == '-') {
+        castle = "-";
+        continue;
+      }
+      if (toupper(fen[i]) == 'K') {
+        castle += fen[i];
+        continue;
+      }
+      if (toupper(fen[i]) == 'Q') {
+        castle += fen[i];
+        continue;
+      }
     }
-    if (toupper(fen[i]) == 'B') {
-      b->turn = BLACK;
-    }
-    if (toupper(fen[i]) == 'N') {
-      Piece piece = createPiece(KNIGHT, isupper(i));
-      b->pieces[rank * 8 + file] = piece;
-      file++;
-      continue;
-    }
-    if (toupper(fen[i]) == 'R') {
-      Piece piece = createPiece(ROOK, isupper(i));
-      b->pieces[rank * 8 + file] = piece;
-      file++;
-      continue;
+    if (state == TURN) {
+      if (toupper(fen[i]) == 'W') {
+        b->turn = WHITE;
+        continue;
+      }
+      if (toupper(fen[i]) == 'B') {
+        b->turn = BLACK;
+        continue;
+      }
     }
-    if (toupper(fen[i]) == 'Q') {
-      Piece piece = createPiece(QUEEN, isupper(i));
-      b->pieces[rank * 8 + file] = piece;
-      file++;
-      continue;
-    }
-    if (toupper(fen[i]) == 'B') {
-      Piece piece = createPiece(BISHOP, isupper(i));
-      b->pieces[rank * 8 + file] = piece;
-      file++;
-      continue;
-    }
-    if (toupper(fen[i]) == 'P') {
-      Piece piece = createPiece(PAWN, isupper(i));
-      b->pieces[rank * 8 + file] = piece;
-      file++;
-      continue;
-    }
-    if (toupper(fen[i]) == 'K') {
-      Piece piece = createPiece(KING, isupper(i));
-      b->pieces[rank * 8 + file] = piece;
-      file++;
-      continue;
+    if (state == POSITION) {
+      if (isdigit(fen[i])) {
+        int move = fen[i] - '0';
+        file += move;
+        if (file > 8) {
+          std::println("Fatal: file was to big");
+          return; // malformed rank
+        }
+        continue;
+      }
+      if (fen[i] == '/') {
+        file = 0;
+        rank++;
+        if (rank > 8) {
+          std::println("Fatal: rank was to big");
+          return; // malformed rank
+        }
+        continue;
+      }
+      if (toupper(fen[i]) == 'N') {
+        Piece piece = createPiece(KNIGHT, isupper(fen[i]));
+        b->pieces[rank * 8 + file] = piece;
+        file++;
+        continue;
+      }
+      if (toupper(fen[i]) == 'R') {
+        Piece piece = createPiece(ROOK, isupper(fen[i]));
+        b->pieces[rank * 8 + file] = piece;
+        file++;
+        continue;
+      }
+      if (toupper(fen[i]) == 'Q') {
+        Piece piece = createPiece(QUEEN, isupper(fen[i]));
+        b->pieces[rank * 8 + file] = piece;
+        file++;
+        continue;
+      }
+      if (toupper(fen[i]) == 'B') {
+        Piece piece = createPiece(BISHOP, isupper(fen[i]));
+        b->pieces[rank * 8 + file] = piece;
+        file++;
+        continue;
+      }
+      if (toupper(fen[i]) == 'P') {
+        Piece piece = createPiece(PAWN, isupper(fen[i]));
+        b->pieces[rank * 8 + file] = piece;
+        file++;
+        continue;
+      }
+      if (toupper(fen[i]) == 'K') {
+        Piece piece = createPiece(KING, isupper(fen[i]));
+        b->pieces[rank * 8 + file] = piece;
+        file++;
+        continue;
+      }
     }
     break;
   }
+  b->castle = castle.empty() ? "-" : castle;
 }
diff --git a/src/main.cpp b/src/main.cpp
index a2d9deb..f958d11 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -11,7 +11,7 @@ Piece NonePiece = {
 int main() {
   board b;
   b.turn = true;
-  b.castle = "KQkq";
+  b.castle = "";
   b.halfMoveClock = 0;
   b.MoveClock = 0;
   for (int i = 0; i < 64; i++) {