From 4dc853bf5d13ccf58ff8d3216debf16b9d7fa596 Mon Sep 17 00:00:00 2001
From: Oceankoh <36119714+Oceankoh@users.noreply.github.com>
Date: Sun, 21 Jan 2024 04:35:27 +0800
Subject: [PATCH 1/2] return failed move when no piece found at origin square

---
 backend/src/chess/engine.ts | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/backend/src/chess/engine.ts b/backend/src/chess/engine.ts
index bd3902e..af486b0 100644
--- a/backend/src/chess/engine.ts
+++ b/backend/src/chess/engine.ts
@@ -53,8 +53,7 @@ const chess = new Chess();
 function movePiece(square1, square2): string | FailedMove {
   const piece = chess.remove(square1);
   if (!piece) {
-    console.log(piece);
-    return null;
+    return new FailedMove(`No piece found at ${square1}`);
   }
   chess.put(piece, square2);
   const validate = validateFen(chess.fen());
@@ -69,8 +68,7 @@ function movePiece(square1, square2): string | FailedMove {
 function promotePiece(square1, square2, piece): string | FailedMove {
   const pawn = chess.remove(square1);
   if (!pawn) {
-    console.log(pawn);
-    return null;
+    return new FailedMove(`No piece found at ${square1}`);
   }
   chess.put({ type: piece, color: pawn.color }, square2);
   const validate = validateFen(chess.fen());
@@ -88,12 +86,16 @@ export async function interpretMove(
 ): Promise<string | FailedMove> {
   const move = await llmInterpretPrompt(prompt, fen);
   if (move instanceof NormalMove) {
+    console.log('return normal move')
     return movePiece(move.square1, move.square2);
   } else if (move instanceof PromotionMove) {
+    console.log('return promotion move')
     return promotePiece(move.square1, move.square2, move.piece);
   } else if (move instanceof InvalidMove) {
+    console.log('return failed move')
     return new FailedMove(move.prompt);
   } else {
+    console.log('return unreachable')
     assertUnreachable(move);
   }
 }

From 2d57561d89eca3c783103f6a3258c64d292ce6d8 Mon Sep 17 00:00:00 2001
From: Oceankoh <36119714+Oceankoh@users.noreply.github.com>
Date: Sun, 21 Jan 2024 04:37:32 +0800
Subject: [PATCH 2/2] verbosity of failure messages

---
 backend/src/chess/engine.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/backend/src/chess/engine.ts b/backend/src/chess/engine.ts
index af486b0..5189330 100644
--- a/backend/src/chess/engine.ts
+++ b/backend/src/chess/engine.ts
@@ -53,7 +53,7 @@ const chess = new Chess();
 function movePiece(square1, square2): string | FailedMove {
   const piece = chess.remove(square1);
   if (!piece) {
-    return new FailedMove(`No piece found at ${square1}`);
+    return new FailedMove(`Tried to move piece at ${square1} to ${square2} but there was no piece found at ${square1}`);
   }
   chess.put(piece, square2);
   const validate = validateFen(chess.fen());
@@ -68,7 +68,7 @@ function movePiece(square1, square2): string | FailedMove {
 function promotePiece(square1, square2, piece): string | FailedMove {
   const pawn = chess.remove(square1);
   if (!pawn) {
-    return new FailedMove(`No piece found at ${square1}`);
+    return new FailedMove(`Tried to promote piece at ${square1}, but there was no piece found at ${square1}`);
   }
   chess.put({ type: piece, color: pawn.color }, square2);
   const validate = validateFen(chess.fen());