package chess

import "mchess_server/types"

func (b *Board) GetNonBlockedRowAndColumn(fromSquare types.Coordinate) []types.Coordinate {
	squaresLeft := fromSquare.GetStraightInDirection(types.Coordinate.Left)
	squaresRight := fromSquare.GetStraightInDirection(types.Coordinate.Right)
	squaresAbove := fromSquare.GetStraightInDirection(types.Coordinate.Up)
	squaresBelow := fromSquare.GetStraightInDirection(types.Coordinate.Down)

	nonBlocked := b.getNonBlockedConsecutive(squaresLeft, fromSquare)
	nonBlocked = append(nonBlocked, b.getNonBlockedConsecutive(squaresRight, fromSquare)...)
	nonBlocked = append(nonBlocked, b.getNonBlockedConsecutive(squaresAbove, fromSquare)...)
	nonBlocked = append(nonBlocked, b.getNonBlockedConsecutive(squaresBelow, fromSquare)...)
	return nonBlocked
}

func (b *Board) GetNonBlockedDiagonals(fromSquare types.Coordinate) []types.Coordinate {
	rightUp := fromSquare.GetDiagonalInDirection(types.Coordinate.Right, types.Coordinate.Up)
	leftUp := fromSquare.GetDiagonalInDirection(types.Coordinate.Left, types.Coordinate.Up)
	leftDown := fromSquare.GetDiagonalInDirection(types.Coordinate.Left, types.Coordinate.Down)
	rightDown := fromSquare.GetDiagonalInDirection(types.Coordinate.Right, types.Coordinate.Down)

	nonBlocked := b.getNonBlockedConsecutive(rightUp, fromSquare)
	nonBlocked = append(nonBlocked, b.getNonBlockedConsecutive(leftUp, fromSquare)...)
	nonBlocked = append(nonBlocked, b.getNonBlockedConsecutive(leftDown, fromSquare)...)
	nonBlocked = append(nonBlocked, b.getNonBlockedConsecutive(rightDown, fromSquare)...)

	return nonBlocked
}

func (b *Board) GetNonBlockedKingMoves(fromSquare types.Coordinate) []types.Coordinate {
	return b.getNonBlockedRaw(fromSquare.GetAllKingMoves(), fromSquare)
}

func (b *Board) GetNonBlockedKnightMoves(fromSquare types.Coordinate) []types.Coordinate {
	return b.getNonBlockedRaw(fromSquare.GetAllKnightMoves(), fromSquare)
}

// returns only those squares in a straight/diagonal that are not blocked
// until it hits a blocking piece (excluding same color, including diff color)
func (b *Board) getNonBlockedConsecutive(
	squaresToCheck []types.Coordinate,
	sourceSquare types.Coordinate,
) []types.Coordinate {
	pieceOnSourceSquare := b.getPieceAt(sourceSquare)
	nonBlocked := []types.Coordinate{}

	for _, square := range squaresToCheck {
		piece := b.getPieceAt(square)
		if piece != nil {
			if piece.GetColor() == pieceOnSourceSquare.GetColor() {
				//We do not append squares with same-colored pieces
				//and also not the squares behind it
				break
			}
			// if there is an opposite colored piece we append it but
			// stop appending the squares behind it
			nonBlocked = append(nonBlocked, square)
			break
		}
		nonBlocked = append(nonBlocked, square)
	}
	return nonBlocked
}

// returns any square in squaresToCheck that are not blocked
func (b *Board) getNonBlockedRaw(
	squaresToCheck []types.Coordinate,
	sourceSquare types.Coordinate,
) []types.Coordinate {
	pieceOnSourceSquare := b.getPieceAt(sourceSquare)
	nonBlocked := []types.Coordinate{}

	for _, square := range squaresToCheck {
		piece := b.getPieceAt(square)
		if piece == nil || piece.GetColor() != pieceOnSourceSquare.GetColor() {
			nonBlocked = append(nonBlocked, square)
		}
	}
	return nonBlocked
}