Blog post four - updating the board model

Pentominoes.playground/Contents.swift

@@ -8,23 +8,23 @@ let board = Board(size: .FiveByTwelve)

let tile = Tile(shape: .O)

for boardSquare in board.squares() {
    if board.canPositionTile(tile, atSquare: boardSquare) {
        print("Can position at \(boardSquare)")
    } 
}
//tile.rotate(true)
//print("Rotated")

tile.rotate(true)
print("Rotated")
board.positionTile(tile, atSquare: Square(row: 4, column: 6))
board

for boardSquare in board.squares() {
    if board.canPositionTile(tile, atSquare: boardSquare) {
        print("Can position at \(boardSquare)")
for square in board.squares() {
    if let tile = board.tileAtSquare(square) {
        print(square)
    }
}





let tile2 = Tile(shape: .P)
board.positionTile(tile2, atSquare: Square(row: 4, column: 8))
board
let tile3 = Tile(shape: .T)
board.removeTile(tile3)
board.removeTile(tile)
board

Pentominoes.playground/Sources/Board.swift

@@ -2,6 +2,19 @@ public class Board: PlayingGrid {
    
    private (set) public var rows: [[Bool]]
    
    private let emptyBoard: [[Bool]]
    
    private struct PlacedTile {
        let square: Square
        let tile: Tile
    }

    private var placedTiles = [PlacedTile]() {
        didSet {
            updateRows()
        }
    }
    
    public struct Size {
        let height: Int
        let width: Int
@@ -23,6 +36,7 @@ public class Board: PlayingGrid {
            rows += [paddingHorizontal + emptyRow + paddingHorizontal]
        }
        rows += fullPaddingVertical
        emptyBoard = rows
    }
}

@@ -31,7 +45,7 @@ extension Board {
        
        for tileSquare in tile.squares() {
            let boardSquare = tileSquare.offsetBy(atSquare)
            if !squareWithinBoard(boardSquare) {
            if !squareWithinGrid(boardSquare) {
                return false
            }
            if tileSquare.occupied == true && squareOccupied(boardSquare) {
@@ -40,4 +54,48 @@ extension Board {
        }
        return true
    }
    
    public func positionTile(tile: Tile, atSquare square: Square) -> Bool {
        if !canPositionTile(tile, atSquare: square) {
            return false
        }
        placedTiles.append(PlacedTile(square: square, tile: tile))
        return true
    }
    
    public func tileAtSquare(square: Square) -> Tile? {
        for placedTile in placedTiles {
            let locationInTile = square.offsetBy(-placedTile.square)
            if placedTile.tile.squareWithinGrid(locationInTile) {
                let occupiedSquares = placedTile.tile.squares().filter { $0.occupied == true }
                for tileSquare in occupiedSquares {
                    if tileSquare == locationInTile {
                        return placedTile.tile
                    }
                }
            }
        }
        return nil
    }
    
    public func removeTile(tile: Tile) -> Tile? {
        if let index = placedTiles.indexOf( { $0.tile === tile } ){
            placedTiles.removeAtIndex(index)
            return tile
        }
        return nil
    }
}

extension Board {
    private func updateRows() {
        rows = emptyBoard
        for placedTile in placedTiles {
            let occupiedSquares = placedTile.tile.squares().filter { $0.occupied == true }
            for tileSquare in occupiedSquares {
                let boardLocation = tileSquare.offsetBy(placedTile.square)
                rows[boardLocation.row][boardLocation.column] = true
            }
        }
    }
}

Pentominoes.playground/Sources/PlayingGrid.swift

@@ -37,10 +37,17 @@ public struct Square {
    
    func offsetBy(square: Square) -> Square {
        return Square(row: self.row + square.row, column: self.column + square.column)
        
    }
}

public prefix func -(square: Square) -> Square {
    return Square(row: -square.row, column: -square.column)
}

public func ==(left: Square, right: Square) -> Bool {
    return left.row == right.row && left.column == right.column
}

public class GridSquareGenerator: GeneratorType {
    var currentRow: Int = 0
    var currentColumn: Int = -1
@@ -94,8 +101,8 @@ extension PlayingGrid {
        }
    }
    
    public func squareWithinBoard(square: Square) -> Bool {
        return square.row < rows.count && square.column < rows[square.row].count
    public func squareWithinGrid(square: Square) -> Bool {
        return square.row >= 0 && square.column >= 0 && square.row < rows.count && square.column < rows[square.row].count
    }
        
    public func squareOccupied(square: Square) -> Bool {