#include <iostream>
#include "MoveGenerator.hpp"
#include "Board.hpp"

MoveGenerator::MoveGenerator(const std::shared_ptr<BitBoard[]> &pieceBB,
                             const std::shared_ptr<BitBoard> &occupiedBB)
        : mPieceBBs(pieceBB), mOccupiedBB(occupiedBB) {

}

void MoveGenerator::generatePawnMoves(const Square &from, const std::optional<Square> &eps,
                                      PieceColor color, MoveVec &moves) const {

    BitBoard targets = 0;
    if (eps.has_value()) {
        targets |= BitBoard::fromIndex(eps.value().index());
    }

    generatePawnMoves(from, targets, color, moves);
}
void MoveGenerator::generatePawnMoves(const Square &from, PieceColor color, MoveVec &moves) {
    generatePawnMoves(from, BitBoard(0), color, moves);
}

void MoveGenerator::generatePawnMoves(const Square &from, BitBoard targets, PieceColor color, MoveVec &moves) const {

    auto fromBB = BitBoard::fromIndex(from.index());
    targets |= mPieceBBs[Board::toIndex(!color)];

    BitBoard movesBB;
    if (color == PieceColor::White) {
        movesBB = BitBoard::pawnNorthAttacks(fromBB, targets) & ~mPieceBBs[Board::toIndex(color)];
        movesBB |= BitBoard::pawnNorthMoves(fromBB, ~*mOccupiedBB);
    } else {
        movesBB = BitBoard::pawnSouthAttacks(fromBB, targets) & ~mPieceBBs[Board::toIndex(color)];
        movesBB |= BitBoard::pawnSouthMoves(fromBB, ~*mOccupiedBB);
    }

    bool isPromotion = movesBB & (Rank1 | Rank8);
    if (isPromotion) {
        generateMovesWithPromotion(from, movesBB, moves);
    } else {
        generateMoves(from, movesBB, moves);
    }
}

void MoveGenerator::generateMoves(const Square &from, BitBoard movesBB, MoveGenerator::MoveVec &moves) {
    while (movesBB) {
        auto to = Square(movesBB.pop());
        moves.emplace_back(from, to, std::nullopt);
    }
}

void MoveGenerator::generateMovesWithPromotion(const Square &from, BitBoard movesBB, MoveGenerator::MoveVec &moves) {
    while (movesBB) {
        auto to = Square(movesBB.pop());
        for (const auto &kItem : Piece::PromotionTypes) {
            moves.emplace_back(from, to, static_cast<PieceType>(kItem));
        }
    }
}