#include "Board.h"
#include <string>
#include <map>
#include <ctype.h>
#include <stdexcept>
#include <sstream>

#include "MoveGeneration.h"

using namespace chessy;
using namespace std;


void Board::resetBoard(void)
{
    whites[PieceType::PAWN]   = 0x000000000000FF00;
    whites[PieceType::ROOK]   = 0x0000000000000081;
    whites[PieceType::KNIGHT] = 0x0000000000000042;
    whites[PieceType::BISHOP] = 0x0000000000000024;
    whites[PieceType::QUEEN]  = 0x0000000000000008;
    whites[PieceType::KING]   = 0x0000000000000010;

    blacks[PieceType::PAWN]   = 0x00FF000000000000;
    blacks[PieceType::ROOK]   = 0x8100000000000000;
    blacks[PieceType::KNIGHT] = 0x4200000000000000;
    blacks[PieceType::BISHOP] = 0x2400000000000000;
    blacks[PieceType::QUEEN]  = 0x0800000000000000;
    blacks[PieceType::KING]   = 0x1000000000000000;
}


void Board::setEmpty(void)
{
    whites[PieceType::PAWN] = 0;
    whites[PieceType::KNIGHT] = 0;
    whites[PieceType::BISHOP] = 0;
    whites[PieceType::ROOK] = 0;
    whites[PieceType::QUEEN] = 0;
    whites[PieceType::KING] = 0;

    blacks[PieceType::PAWN] = 0;
    blacks[PieceType::KNIGHT] = 0;
    blacks[PieceType::BISHOP] = 0;
    blacks[PieceType::ROOK] = 0;
    blacks[PieceType::QUEEN] = 0;
    blacks[PieceType::KING] = 0;
}


bool Board::tryToMove(Bitboard start, Bitboard end, Bitboard& b)
{
    if (start & b)
        b = b ^ start ^ end;
    return false;
}


void Board::setBoard(const std::string& fenPosition)
{
    int row = 7, column = 0;
    map<char, Bitboard*> boards {
        { 'p', &blacks[PieceType::PAWN] },
        { 'n', &blacks[PieceType::KNIGHT] },
        { 'b', &blacks[PieceType::BISHOP] },
        { 'r', &blacks[PieceType::ROOK] },
        { 'q', &blacks[PieceType::QUEEN] },
        { 'k', &blacks[PieceType::KING] },
        { 'P', &whites[PieceType::PAWN] },
        { 'N', &whites[PieceType::KNIGHT] },
        { 'B', &whites[PieceType::BISHOP] },
        { 'R', &whites[PieceType::ROOK] },
        { 'Q', &whites[PieceType::QUEEN] },
        { 'K', &whites[PieceType::KING] }
    };
    setEmpty();
    for (auto character : fenPosition) {
        if (character >= '0' && character <= '9') {
            column += character - '0';
        }
        else if (character == '/') {
            -- row;
            column = 0;
        }
        else {
            auto board = boards.find(character);
            if (board != boards.end()) {
                *(board->second) |= Bitboard::fromIndex({row, column});
            }
            else {
                throw runtime_error("invalid piece type "s + character);
            }
            ++ column;
        }
        if (row < -1 || column > 8)
            throw runtime_error("invalid board string "s + fenPosition);
    }
}


// a bit hacky, sry
std::string Board::getFenBoard(void) const
{
    using namespace std;
    stringstream str;
    for (int row = 7; row >= 0; row--) {
        int counter = 0;
        for (int column = 0; column < 8; column++) {
            PieceType black = getBlackAtPosition({ row, column });
            PieceType white = getWhiteAtPosition({ row, column });
            //str << " " << Bitboard::fromIndex({row, column}) << " " << " ";;
            //str << "row,column,index: " << row << "," << column << "," <<
            //    int(Index(row, column).index) << " ";

            if (black == PieceType::EMPTY && white == PieceType::EMPTY)
                ++ counter;
            else if (counter > 0) {
                str << counter;
                counter = 0;
            }
            switch (black) {
                case PieceType::PAWN:   str << 'p'; break;
                case PieceType::KNIGHT: str << 'n'; break;
                case PieceType::BISHOP: str << 'b'; break;
                case PieceType::ROOK:   str << 'r'; break;
                case PieceType::QUEEN:  str << 'q'; break;
                case PieceType::KING:   str << 'k'; break;
                default:
                switch (white) {
                    case PieceType::PAWN:   str << 'P'; break;
                    case PieceType::KNIGHT: str << 'N'; break;
                    case PieceType::BISHOP: str << 'B'; break;
                    case PieceType::ROOK:   str << 'R'; break;
                    case PieceType::QUEEN:  str << 'Q'; break;
                    case PieceType::KING:   str << 'K'; break;
                    default:;
                }
            }
        }
        if (counter > 0)
            str << counter;
        if (row != 0)
            str << "/";
    }
    return str.str();
}


PieceType Board::getWhiteAtPosition(Index i) const
{
    Bitboard mask = Bitboard::fromIndex(i);
    for (int i = 0; i < 6; i++)
        if (whites[i] & mask)
            return (PieceType) i;
    return PieceType::EMPTY;
}


PieceType Board::getBlackAtPosition(Index i) const
{
    Bitboard mask = Bitboard::fromIndex(i);
    for (int i = 0; i < 6; i++)
        if (blacks[i] & mask)
            return (PieceType) i;
    return PieceType::EMPTY;
}


PieceType Board::getAtPosition(Index i) const
{
    PieceType b = getWhiteAtPosition(i);
    if (b != PieceType::EMPTY)
        return b;
    return getBlackAtPosition(i);;
}


void Board::move(const Move& move)
{
    Bitboard start = Bitboard::fromIndex(move.origin);
    Bitboard end = Bitboard::fromIndex(move.destination);

    for (Bitboard& b : whites)
        if (b & end) {
            b ^= end;
            goto move;
        }
    for (Bitboard& b : blacks)
        if (b & end) {
            b ^= end;
            goto move;
        }

    move:

    for (Bitboard& b : whites) {
        if (b & end)
            b ^= end;
        if (b & start) {
            b &= ~start;
            b |= end;
            return;
        }
    }
    for (Bitboard& b : blacks) {
        if (b & start) {
            b &= ~start;
            b |= end;
            return;
        }
    }
}


void Board::removeAt(Index i)
{
    Bitboard mask = ~Bitboard::fromIndex(i);
    for (Bitboard& b : whites)
        b &= mask;
    for (Bitboard& b : blacks)
        b &= mask;
}


Bitboard Board::getWhites(void) const
{
    return whites[0] | whites[1] | whites[2] | whites[3] | whites[4] | whites[5];
}


Bitboard Board::getBlacks(void) const
{
    return blacks[0] | blacks[1] | blacks[2] | blacks[3] | blacks[4] | blacks[5];
}


Bitboard Board::getOccupied(void) const
{
    return getBlacks() | getWhites();
}


Bitboard Board::getFree(void) const
{
    return ~getOccupied();
}


#include <iostream>
template<Side side>
bool Board::isCheck(void) const
{
    constexpr Side enemy = otherSide(side);
    Index kingIndex = getKing<side>().getLeastSignificantBit();
    KnightMoveGenerator nmg{ kingIndex, 0 };
    if (nmg.getBitboard() & getKnights<enemy>())
        return true;

    PrimitiveBishopMoveGenerator pbmg{ kingIndex, get<enemy>(), get<side>() };
    if (pbmg.getBitboard() & (getBishops<enemy>() | getQueens<enemy>()))
        return true;

    PrimitiveRookMoveGenerator prmg{ kingIndex, get<enemy>(), get<side>() };
    if (prmg.getBitboard() & (getRooks<enemy>() | getQueens<enemy>()))
        return true;

    if (side == WHITE_SIDE) {
        if (kingIndex.getRow() < 6) {
            if (kingIndex.getColumn() > 0)
                if (getKing<side>().neOne() & getPawns<enemy>())
                    return true;
            if (kingIndex.getColumn() < 7)
                if (getKing<side>().nwOne() & getPawns<enemy>())
                    return true;
        }
    }
    else {
        if (kingIndex.getRow() > 1) {
            if (kingIndex.getColumn() > 0)
                if (getKing<side>().seOne() & getPawns<enemy>())
                    return true;
            if (kingIndex.getColumn() < 7)
                if (getKing<side>().swOne() & getPawns<enemy>())
                    return true;
        }
    }

    KingMoveGenerator kmg{ getKing<side>(), 0 };
    if (kmg.getBitboard() & getKing<enemy>())
        return true;

    return false;
}

template bool Board::isCheck<WHITE_SIDE>(void) const;
template bool Board::isCheck<BLACK_SIDE>(void) const;