From ee434da2fcd7873633d076790dd4689e81524fe5 Mon Sep 17 00:00:00 2001
From: eug-vs <eug-vs@keemail.me>
Date: Mon, 14 Jun 2021 15:55:02 +0300
Subject: feat: generate legal moves

---
 src/main.c   | 50 ++++++++++++++++++++++++++++++++++++++++++++++++--
 src/pieces.h |  8 +++++++-
 2 files changed, 55 insertions(+), 3 deletions(-)

diff --git a/src/main.c b/src/main.c
index 69f0b43..786c882 100644
--- a/src/main.c
+++ b/src/main.c
@@ -110,14 +110,57 @@ void input_move(int move[2]) {
   move[1] = notation_to_index(file_destination, rank_destination);
 };
 
+int generate_legal_moves(int origin, int* board) {
+  int piece = board[origin];
+  int* move;
+
+  switch (piece) {
+    case KNIGHT:
+      move = knightMoves;
+      break;
+    case BISHOP:
+      move = bishopMoves;
+      break;
+    case ROOK:
+      move = rookMoves;
+      break;
+    case QUEEN:
+      move = queenMoves;
+      break;
+    case KING:
+      move = kingMoves;
+      break;
+    case PAWN:
+      move = pawnMoves;
+      break;
+    default:
+      move = NULL;
+  }
+
+  while(*move) {
+    for (int square = origin; !(square & 0x88); square += *move) {
+      if (square != origin) {
+        if (board[square] != EMPTY) break;
+        board[square] = VISUAL;
+        if (piece == PAWN || piece == KNIGHT || piece == KING) break;
+      }
+    }
+
+    move++;
+  }
+}
+
 int apply_move(int move[2], int* board) {
   int origin = move[0];
   int destination = move[1];
 
   if ((origin & 0x88) || (destination & 0x88)) return 0;
 
-  board[destination] = board[origin];
+  int piece = board[origin];
+
+  board[destination] = piece;
   board[origin] = EMPTY;
+
   return board[destination];
 }
 
@@ -129,7 +172,10 @@ int main() {
   int move[2];
   while (1) {
     input_move(move);
-    if (apply_move(move, board)) print_board(board);
+    if (apply_move(move, board)) {
+      generate_legal_moves(move[1], board);
+      print_board(board);
+    }
     else puts("Invalid move!");
   }
 
diff --git a/src/pieces.h b/src/pieces.h
index 2d5a02a..9821695 100644
--- a/src/pieces.h
+++ b/src/pieces.h
@@ -13,7 +13,7 @@
 
 
 char* pieces[] = {
-  ".", "#",
+  ".", "*",
   "♟︎", "♙",
   "♞", "♘",
   "♝", "♗",
@@ -22,6 +22,12 @@ char* pieces[] = {
   "♚", "♔",
 };
 
+int bishopMoves[] = { 17, 15, -17, -15, 0 };
+int rookMoves[] = { 16, 1, -1, -16, 0 };
+int queenMoves[] = { 17, 16, 15, 1, -1, -15, -16, -17, 0 };
+int knightMoves[] = { 33, 31, 18, 14, -33, -31, -18, -14, 0 };
+int kingMoves[] = { 17, 16, 15, 1, -1, -15, -16, -17, 0 };
+int pawnMoves[] = { 17, 16, 15, 0 };
 
 #define FILE_MASK 0b1111
 
-- 
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