import FDChessboardView

public protocol FDChessboardViewDataSource: class {
    /// What piece is on the square?
    func chessboardView(_ board: FDChessboardView, pieceForSquare square: FDChessboardSquare) -> FDChessboardPiece?

    /// The last move
    func chessboardViewLastMove(_ board: FDChessboardView) -> (from:FDChessboardSquare, to:FDChessboardSquare)?

    /// The premove
    func chessboardViewPremove(_ board: FDChessboardView) -> (from:FDChessboardSquare, to:FDChessboardSquare)?
}

public protocol FDChessboardViewDelegate: class {
    /// Where can this piece move to?
    func chessboardView(_ board: FDChessboardView, legalDestinationsForPieceAtSquare from: FDChessboardSquare) -> [FDChessboardSquare]

    /// Before a move happenes
    func chessboardView(_ board: FDChessboardView, canMoveFrom from: FDChessboardSquare, to: FDChessboardSquare, withPromotion promotion: FDChessboardPiece?) -> Bool

    /// After a move happened
    func chessboardView(_ board: FDChessboardView, didMoveFrom from: FDChessboardSquare, to: FDChessboardSquare, withPromotion promotion: FDChessboardPiece?)
}

/// The location of a square on a chess board
public struct FDChessboardSquare: Hashable {
    /// From 0...7 (a...h)
    public let file: Int
    
    /// From 0...7 (white king starting position to black king starting position)
    public let rank: Int
}

/// The pieces on a chess board
public enum FDChessboardPiece: String {
    case WhitePawn
    case BlackPawn
    case WhiteKnight
    case BlackKnight
    case WhiteBishop
    case BlackBishop
    case WhiteRook
    case BlackRook
    case WhiteQueen
    case BlackQueen
    case WhiteKing
    case BlackKing
}

/// Display for a chess board
@IBDesignable open class FDChessboardView: UIView {
    @IBInspectable open var lightBackgroundColor: UIColor
    @IBInspectable open var darkBackgroundColor: UIColor
    open var targetBackgroundColor: UIColor
    open var legalBackgroundColor: UIColor
    open var lastMoveColor: UIColor
    open var premoveColor: UIColor
    open weak var dataSource: FDChessboardViewDataSource?
    open weak var delegate: FDChessboardViewDelegate?
    open var doesAnimate: Bool
    open var doesShowLegalSquares: Bool
    open var doesShowLastMove: Bool
    open var doesShowPremove: Bool

    /// Add a piece onto the board
    open func setPiece(_ piece: FDChessboardPiece?, forSquare square: FDChessboardSquare)

    /// Repull all board information from data source
    open func reloadData()

    /// Move a piece on the board, clears any prior premove
    open func move(_ piece: FDChessboardPiece, from: FDChessboardSquare, to: FDChessboardSquare, promotedTo promoted: FDChessboardPiece?)
    
    /// Premove a piece on the board, clears any prior premove
    open func premove(_ piece: FDChessboardPiece, from: FDChessboardSquare, to: FDChessboardSquare, promotedTo promoted: FDChessboardPiece?)
    
    /// Removes any premove on the board
    open func clearPremove()
    
    /// Move a piece on the board, clears any prior premove
    open func unmove(_ piece: FDChessboardPiece, from: FDChessboardSquare, to: FDChessboardSquare, promotedTo promoted: FDChessboardPiece?, capturing: FDChessboardPiece)
}