#include "BitBoard.hpp"

BitBoard::BitBoard(uint64_t v) {
    mBoard = v;
}

std::ostream &operator<<(std::ostream &os, const BitBoard &board) {
    // For debugging only, performance isn't important
    for (int i = 7; i >= 0; i--) {
        int rank = i * 8;
        for (int j = 0; j < 8; j++) {
            // Get the piece for this index. Assume it exists.
            // Print piece, otherwise '.';
            if (board.mBoard & (1ULL << (rank + j))) {
                os << 1;
            } else {
                os << '.';
            }

            os << ' ';
        }
        os << '\n';
    }

    return os;
}

BitBoard BitBoard::genShift(BitBoard x, const int s) {
    return (s < 0) ? (x >> -s) : (s > 63) ? x : (x << s);
}

BitBoard BitBoard::northFill() const {
    BitBoard result(mBoard);
    result |= (result << 8);
    result |= (result << 16);
    result |= (result << 32);
    return (result << 8);
}

BitBoard BitBoard::southFill() const {
    BitBoard result(mBoard);
    result |= (result >> 8);
    result |= (result >> 16);
    result |= (result >> 32);
    return result;
}

BitBoard BitBoard::fileFill() const {
    return northFill() | southFill();
}

BitBoard BitBoard::kingAttacks(const BitBoard bb) {
    BitBoard result = bb.east() | bb.west() | bb;
    result |= (result.north() | result.south());
    result ^= bb;

    return result;
}

BitBoard BitBoard::bishopAttacks(BitBoard bishops, BitBoard empty) {
    BitBoard result = 0;
    BitBoard diag1 = bishops;
    BitBoard diag2 = bishops;
    empty ^= bishops;

    for (int i = 0; i < 7; i++) {
        result |= (diag1 | diag2);
        diag1 = (diag1.northWest() | diag1.southEast()) & empty;
        diag2 = (diag2.northEast() | diag2.southWest()) & empty;
    }

    return (result | diag1.northWest() | diag1.southEast() | diag2.northEast() | diag2.southWest()) & ~bishops;
}

BitBoard BitBoard::pawnNorthAttacks(BitBoard pawns, BitBoard targets) {
    return (pawns.northEast() | pawns.northWest()) & targets;
}
BitBoard BitBoard::pawnNorthMoves(BitBoard pawns, BitBoard empty) {
    pawns = pawns.north() & empty;
    return (pawns | (pawns.north() & Rank4)) & empty;
}

BitBoard BitBoard::pawnSouthAttacks(BitBoard pawns, BitBoard targets) {
    return (pawns.southEast() | pawns.southWest()) & targets;
}
BitBoard BitBoard::pawnSouthMoves(BitBoard pawns, BitBoard empty) {
    pawns = pawns.south() & empty;
    return (pawns | (pawns.south() & Rank5)) & empty;
}