From ba260f2895d6a60194c8ede3dedf734153753f55 Mon Sep 17 00:00:00 2001
From: WanCW <contact@wancw.idv.tw>
Date: Mon, 28 Apr 2025 16:50:49 +0800
Subject: [PATCH] refactor: merge all game state into 1 state variable

---
 src/App.css |  13 ++-
 src/App.tsx | 247 +++++++++++++++++++++++++++++-----------------------
 2 files changed, 150 insertions(+), 110 deletions(-)

diff --git a/src/App.css b/src/App.css
index b7b6a48..3bfd7ec 100644
--- a/src/App.css
+++ b/src/App.css
@@ -9,8 +9,11 @@
   display: flex;
   flex-direction: column;
   gap: 10px;
+  margin-top: 1em;
+}
+.messages {
+  line-height: 1em;
 }
-
 .board-row {
   display: flex;
   flex-direction: row;
@@ -28,6 +31,14 @@
   cursor: pointer;
 }
 
+.game-set .board-cell {
+  cursor: not-allowed;
+}
+
+.game-set .board-cell:hover {
+  background-color: unset;
+}
+
 .board-cell:hover {
   background-color: #f0f0f0;
 }
diff --git a/src/App.tsx b/src/App.tsx
index 838919a..ff66e0b 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -1,6 +1,5 @@
-import { useEffect, useState } from 'react'
+import React, { useEffect, useState } from 'react'
 import './App.css'
-import React from 'react';
 
 type Symbol = 'X' | 'O';
 
@@ -12,147 +11,177 @@ type CellState = {
 type RowState = CellState[];
 type BoardState = RowState[];
 
-type CellClickHandler = (row: number, col: number) => boolean;
-type CellProps = {
-  row: number;
-  col: number;
-  state: CellState;
-  onClick?: CellClickHandler;
-}
+type CellClickHandler = (row: number, col: number) => void;
+type CellProps = CellState & { rowIndex: number, columnIndex: number, onClick?: CellClickHandler };
 
-
-function Cell({row, col, state: {symbol, isFading}, onClick}: CellProps) {
-  const onClick1 = (() => {
-    onClick && onClick(row, col)
-  });
-
-  return <div className={`board-cell ${isFading ? 'fading' : ''}`} id={`cell-${row}-${col}`}
-              onClick={onClick1}>{symbol}</div>;
+function Cell({ rowIndex, columnIndex, symbol, isFading, onClick }: CellProps) {
+  return <div className={`board-cell ${isFading ? 'fading' : ''}`} onClick={() => onClick && onClick(rowIndex, columnIndex)}>{symbol}</div>;
 }
 
 type RowProps = {
-  index: number, state: RowState
+  index: number,
+  state: RowState
   onCellClick: CellClickHandler;
 };
 
-function Row({state, index, onCellClick}: RowProps) {
+function Row({ state, index, onCellClick }: RowProps) {
   return (
     <div className="board-row">
-      {state.map((cell: CellState, i) => <Cell key={`cell-${index}-${i}`} row={index} col={i} state={cell}
-                                               onClick={onCellClick}/>)}
+      {state.map((cellState: CellState, i) => <Cell
+        key={`cell-${index}-${i}`}
+        rowIndex={index}
+        columnIndex={i}
+        {...cellState}
+        onClick={onCellClick}/>)}
     </div>
   )
 }
 
 type BoardProps = {
   state: BoardState;
+  hasWinner?: boolean;
   onCellClick: CellClickHandler;
 }
 
-function Board({state, onCellClick}: BoardProps) {
+function Board({ state, hasWinner, onCellClick }: BoardProps) {
   return (
-    <div className="board">
+    <div className={`board ${hasWinner ? 'game-set' : ''}`}>
       {state.map((row, i) => <Row key={`row-${i}`} index={i} state={row} onCellClick={onCellClick}/>)}
     </div>
   )
-
 }
 
-function findWinner(state: BoardState): Symbol | undefined {
-  // check rows
-  if (state[0]?.[0]?.symbol === state[0]?.[1]?.symbol && state[0]?.[1]?.symbol === state[0]?.[2]?.symbol)
-    return state[0]?.[0]?.symbol;
+function hasWin(board: BoardState, size: number, row: number, column: number): boolean {
+  const targetCell = board[row]?.[column];
+  if (!targetCell) { return false; }
 
-  if (state[1]?.[0]?.symbol === state[1]?.[1]?.symbol && state[1]?.[1]?.symbol === state[1]?.[2]?.symbol)
-    return state[1]?.[0]?.symbol;
-
-  if (state[2]?.[0]?.symbol === state[2]?.[1]?.symbol && state[2]?.[1]?.symbol === state[2]?.[2]?.symbol)
-    return state[2]?.[0]?.symbol;
-
-  // check columns
-  if (state[0]?.[0]?.symbol === state[1]?.[0]?.symbol && state[1]?.[0]?.symbol === state[2]?.[0]?.symbol)
-    return state[0]?.[0]?.symbol;
-
-  if (state[0]?.[1]?.symbol === state[1]?.[1]?.symbol && state[1]?.[1]?.symbol === state[2]?.[1]?.symbol)
-    return state[0]?.[1]?.symbol;
-
-  if (state[0]?.[2]?.symbol === state[1]?.[2]?.symbol && state[1]?.[2]?.symbol === state[2]?.[2]?.symbol)
-    return state[0]?.[2]?.symbol;
-
-  // check diagonals
-  if (state[0]?.[0]?.symbol === state[1]?.[1]?.symbol && state[1]?.[1]?.symbol === state[2]?.[2]?.symbol)
-    return state[0]?.[0]?.symbol;
-
-  if (state[0]?.[2]?.symbol === state[1]?.[1]?.symbol && state[1]?.[1]?.symbol === state[2]?.[0]?.symbol)
-    return state[0]?.[2]?.symbol;
-
-  return undefined;
-}
-
-function App() {
-  const [nextPlayer, setNextPlayer] = useState<Symbol>('O')
-
-  const [state, updateState] = useState<CellState[][]>([
-    [{}, {}, {}],
-    [{}, {}, {}],
-    [{}, {}, {}],
-  ])
-
-  const [latestCells, updateLatestCells] = useState<{ row: number, col: number }[]>([]);
-  const [winner, updateWinner] = useState<Symbol | undefined>(undefined);
-
-  const onClick = (rowNumber: number, colNumber: number): boolean => {
-    const targetCell = state[rowNumber]?.[colNumber];
-    if (winner || !targetCell || targetCell.symbol) {
-      return false;
+  let win = true;
+  for (let r = 0; r < size; r++) {
+    if (board[r]?.[column]?.symbol !== targetCell.symbol) {
+      win = false;
+      break;
     }
+  }
+  if (win) {
+    return true;
+  }
 
-    updateState((prevState) => prevState.map((row, r) => row.map((cell, c) => {
-      if (r === rowNumber && c === colNumber) {
-        return {...cell, symbol: nextPlayer};
-      }
-      if (latestCells.length >= 5 && latestCells[0] && latestCells[0].row === r && latestCells[0].col === c) {
-        return {...cell, isFading: true};
-      }
-      return cell.isFading ? {symbol: undefined, isFading: false} : cell;
-    })));
-
-    updateLatestCells((prevState) => {
-      console.info('updating latestCells', {rowNumber, colNumber});
-      const appended = [...prevState, {row: rowNumber, col: colNumber}];
-      if (appended.length >= 6) {
-        return appended.slice(1);
-      }
-      return appended;
-    })
-    setNextPlayer(nextPlayer === 'X' ? 'O' : 'X');
+  win = true;
+  for (let c = 0; c < size; c++) {
+    if (board[row]?.[c]?.symbol !== targetCell.symbol) {
+      win = false;
+      break;
+    }
+  }
+  if (win) {
+    return true;
+  }
+  if (row !== column) {
     return false;
-  };
+  }
 
-  useEffect(() => {
-    const winner = findWinner(state);
-    if (winner) {
-      updateWinner(winner);
+
+  win = true;
+  for (let i = 0; i < size; i++) {
+    if (board[i]?.[i]?.symbol !== targetCell.symbol) {
+      win = false;
+      break;
     }
-  }, [state]);
+  }
+
+  return win;
+}
+
+type MoveRecord = {
+  row: number;
+  col: number;
+  player: Symbol;
+};
+
+type GameState = {
+  board: BoardState;
+  latestMoves:MoveRecord[];
+  currentPlayer: Symbol;
+  winner?: Symbol;
+}
+
+function useBoardState(size: number = 3): [GameState, { reset: ()=> void; playOn: (row: number, col: number) => boolean } ]  {
+  const [state, updateState] = useState<GameState>({
+    board: Array(size).fill(Array(size).fill({})),
+    latestMoves: [],
+    currentPlayer: 'O',
+  });
+
+  return [
+    state,
+    {
+      reset: () => updateState({
+        board: Array(size).fill(Array(size).fill({})),
+        latestMoves: [],
+        currentPlayer: 'O',
+      }),
+
+      playOn: (row: number, col: number) => {
+        if (state.winner) {
+          return false;
+        }
+
+        const targetCell = state.board[row]?.[col];
+        if (!targetCell || targetCell.symbol) {
+          return false;
+        }
+
+        const cellToFading = state.latestMoves.length >= (2*size-1) ? state.latestMoves[0] : undefined;
+        const fadingRow = cellToFading?.row;
+        const fadingCol = cellToFading?.col;
+
+        const nextState: GameState = {
+          board: state.board.map((oldRow, r) => oldRow.map((oldCell, c)=> {
+            return {
+              ...(oldCell.isFading ? {} : oldCell),
+              ...(r===row && c===col ? { symbol: state.currentPlayer } : undefined),
+              ...(r===fadingRow && c===fadingCol ? { isFading: true} : undefined),
+            };
+          })),
+
+          latestMoves: [
+            ...state.latestMoves,
+            {
+              row,
+              col,
+              player: state.currentPlayer,
+            }
+          ].slice(-2*size+1),
+
+          currentPlayer: state.currentPlayer === 'X' ? 'O' : 'X' as Symbol,
+        };
+
+        if (hasWin(nextState.board, size, row, col)) {
+          nextState.winner = state.currentPlayer;
+        }
+        updateState(nextState);
+
+        return true;
+      },
+    },
+  ];
+}
+function App() {
+  const [state, { playOn, reset: resetGame }] = useBoardState(5);
+
+  const nextPlayer = state.currentPlayer;
+  const latestCells = state.latestMoves;
+  const winner = state.winner;
 
   return (
     <>
-      <Board state={state} onCellClick={onClick}/>
+      <Board state={state.board} hasWinner={!!winner } onCellClick={playOn}/>
       <div className="messages">
-        {winner ? <p>Winner is {winner}</p> : <p>Next player is <em>{nextPlayer}</em></p>}
-        {latestCells.length === 0 && (<p>Click any cell to start</p>)}
-        {winner && <p onClick={() => {
-
-          updateState((prevState) => prevState.map((row, r) => row.map((cell, c) => {
-            return {};
-          })));
-
-          updateLatestCells([]);
-
-          setNextPlayer('O');
-          updateWinner(undefined);
-        }}>Click to restart</p>}
+        <p>
+          <span style={{marginRight: '1em'}}>{winner ? `Winner is ${winner}` : (<>Next player is <em>{nextPlayer}</em></>)}</span>
+          {latestCells.length === 0 && ("Click any cell to start")}
+          {winner && <button onClick={resetGame}>Click to restart</button>}
+        </p>
       </div>
     </>
   )