function Square(props) {
  return (
    <button 
      className={"square " + props.extraClass}
      onClick={props.onClick}
      >
      {props.value}
    </button>
  ); 
}

class Board extends React.Component {
  renderSquare(i) {
    return <Square 
             value={this.props.squares[i]} 
             extraClass='is-success'
             onClick={() => this.props.onClick(i)}
           />;
  }
  
  createBoardDivs() {
    let divs = [];
    
    for (let i = 0; i < 3; i++) {
      let children = []

      for (let j = 0; j < 3; j++) {
        children.push(<span key={3*i+j}>{this.renderSquare(3*i+j)}</span>)
      }

      divs.push(<div key={i} className="board-row">{children}</div>)
    }
    
    return divs;
  }

  render() {
    return (
      <div>
        {this.createBoardDivs()}
      </div>
    );
  }
}

class Game extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      history: [{
        squares: Array(9).fill(null)
      }],
      stepNumber: 0,
      clickedSquare: [],
      xIsNext: true,
      winningTriplet: []
    }
  }
  
  handleClick(i) {
    const history = this.state.history.slice(0, this.state.stepNumber + 1);
    const current = history[history.length - 1];
    const squares = current.squares.slice();
    const clickedSquare = this.state.clickedSquare.slice(0, this.state.stepNumber);
    if (this.calculateWinner(squares) || squares[i]) {
      return;
    }
    squares[i] = this.state.xIsNext ? "X" : "O";
    this.setState({ 
      history: history.concat([{
        squares: squares
      }]),
      stepNumber: history.length,
      clickedSquare: clickedSquare.concat(i),
      xIsNext: !this.state.xIsNext,
      isMovesReverse: false
    });
  }
  
  jumpTo(step) {
    this.setState({
      stepNumber: step,
      xIsNext: (step % 2) === 0
    });
  }
  
  sortMoves(moves) {
    this.setState({
      isMovesReverse: !this.state.isMovesReverse
    })
  }
  
  createMoves(history) {
    const moves = history.map((step,move) => {
      const clickedSquare = this.state.clickedSquare[move-1];
      const row = Math.floor(clickedSquare / 3);
      const col = clickedSquare - (row * 3); 
      const desc = move ?
            "Go to move #" + move + " (" + (row+1) + "," + (col+1) + ")": 
            "Go to game start";
      const extraClassBold = (move === this.state.stepNumber) ?
            "is-bold":
            "";
      return (
        <li key={move}>
          <button onClick={() => this.jumpTo(move)} className={extraClassBold}>{desc}</button>
        </li>
      );
    });
    
    return (this.state.isMovesReverse) ? moves.reverse() : moves;
  }
  
  calculateWinner(squares) {
    const lines = [
      [0, 1, 2],
      [3, 4, 5],
      [6, 7, 8],
      [0, 3, 6],
      [1, 4, 7],
      [2, 5, 8],
      [0, 4, 8],
      [2, 4, 6],
    ];
    for (let i = 0; i < lines.length; i++) {
      const [a, b, c] = lines[i];
      if (squares[a] && squares[a] === squares[b] && squares[a] === squares[c]) {
        return squares[a];
      }
    }
    return null;
  }
  
  render() {
    const history = this.state.history;
    const current = history[this.state.stepNumber];
    const winner = this.calculateWinner(current.squares);

    const moves = this.createMoves(history);
    
    let status;
    if (winner) {
      status = "Winner: " + winner;
    } else {
      status = "Next player: " + (this.state.xIsNext ? "X" : "O");
    }
    
    return (
      <div className="game">
        <div className="game-board">
          <Board 
            squares={current.squares}
            onClick={(i) => this.handleClick(i)}
          />
        </div>
        <div className="game-info">
          <div>{status}</div>
          <button onClick={() => this.sortMoves()}>Toggle</button>
          <ol>{moves}</ol>
        </div>
      </div>
    );
  }
}

// ========================================

ReactDOM.render(
  <Game />,
  document.getElementById('root')
);