#include <cassert>

#include <cstring> // For std::memset

#include "material.h"

#include "thread.h"

using namespace std;

namespace Stockfish {

namespace {

#define S(mg, eg) make_score(mg, eg)

// Polynomial material imbalance parameters

// One Score parameter for each pair (our piece, another of our pieces)

constexpr Score QuadraticOurs[][PIECE_TYPE_NB] = {

// OUR PIECE 2

// bishop pair pawn knight bishop rook queen

{S(1419, 1455) }, // Bishop pair

{S( 101, 28), S( 37, 39) }, // Pawn

{S( 57, 64), S(249, 187), S(-49, -62) }, // Knight OUR PIECE 1

{S( 0, 0), S(118, 137), S( 10, 27), S( 0, 0) }, // Bishop

{S( -63, -68), S( -5, 3), S(100, 81), S(132, 118), S(-246, -244) }, // Rook

{S(-210, -211), S( 37, 14), S(147, 141), S(161, 105), S(-158, -174), S(-9,-31) } // Queen

};

// One Score parameter for each pair (our piece, their piece)

constexpr Score QuadraticTheirs[][PIECE_TYPE_NB] = {

// THEIR PIECE

// bishop pair pawn knight bishop rook queen

{ }, // Bishop pair

{S( 33, 30) }, // Pawn

{S( 46, 18), S(106, 84) }, // Knight OUR PIECE

{S( 75, 35), S( 59, 44), S( 60, 15) }, // Bishop

{S( 26, 35), S( 6, 22), S( 38, 39), S(-12, -2) }, // Rook

{S( 97, 93), S(100, 163), S(-58, -91), S(112, 192), S(276, 225) } // Queen

};

#undef S

// Endgame evaluation and scaling functions are accessed directly and not through

// the function maps because they correspond to more than one material hash key.

Endgame<KXK> EvaluateKXK[] = { Endgame<KXK>(WHITE), Endgame<KXK>(BLACK) };

Endgame<KBPsK> ScaleKBPsK[] = { Endgame<KBPsK>(WHITE), Endgame<KBPsK>(BLACK) };

Endgame<KQKRPs> ScaleKQKRPs[] = { Endgame<KQKRPs>(WHITE), Endgame<KQKRPs>(BLACK) };

Endgame<KPsK> ScaleKPsK[] = { Endgame<KPsK>(WHITE), Endgame<KPsK>(BLACK) };

Endgame<KPKP> ScaleKPKP[] = { Endgame<KPKP>(WHITE), Endgame<KPKP>(BLACK) };

// Helper used to detect a given material distribution

bool is_KXK(const Position& pos, Color us) {

return !more_than_one(pos.pieces(~us))

&& pos.non_pawn_material(us) >= RookValueMg;

}

bool is_KBPsK(const Position& pos, Color us) {

return pos.non_pawn_material(us) == BishopValueMg

&& pos.count<PAWN>(us) >= 1;

}

bool is_KQKRPs(const Position& pos, Color us) {

}

/// imbalance() calculates the imbalance by comparing the piece count of each

/// piece type for both colors.

template<Color Us>

Score imbalance(const int pieceCount[][PIECE_TYPE_NB]) {

}

} // namespace

namespace Material {

Entry* probe(const Position& pos) {

Key key = pos.material_key();

Entry* e = pos.this_thread()->materialTable[key];

if (e->key == key)

return e;

std::memset(e, 0, sizeof(Entry));

e->key = key;

e->factor[WHITE] = e->factor[BLACK] = (uint8_t)SCALE_FACTOR_NORMAL;

Value npm_w = pos.non_pawn_material(WHITE);

Value npm_b = pos.non_pawn_material(BLACK);

Value npm = std::clamp(npm_w + npm_b, EndgameLimit, MidgameLimit);

// Map total non-pawn material into [PHASE_ENDGAME, PHASE_MIDGAME]

e->gamePhase = Phase(((npm - EndgameLimit) * PHASE_MIDGAME) / (MidgameLimit - EndgameLimit));

// Let's look if we have a specialized evaluation function for this particular

// material configuration. Firstly we look for a fixed configuration one, then

// for a generic one if the previous search failed.

if ((e->evaluationFunction = Endgames::probe<Value>(key)) != nullptr)

return e;

for (Color c : { WHITE, BLACK })

if (is_KXK(pos, c))

{

e->evaluationFunction = &EvaluateKXK[c];

return e;

}

// OK, we didn't find any special evaluation function for the current material

// configuration. Is there a suitable specialized scaling function?

const auto* sf = Endgames::probe<ScaleFactor>(key);

if (sf)

{

e->scalingFunction[sf->strongSide] = sf; // Only strong color assigned

return e;

}

// We didn't find any specialized scaling function, so fall back on generic

// ones that refer to more than one material distribution. Note that in this

// case we don't return after setting the function.

for (Color c : { WHITE, BLACK })

{

if (is_KBPsK(pos, c))

e->scalingFunction[c] = &ScaleKBPsK[c];

else if (is_KQKRPs(pos, c))

e->scalingFunction[c] = &ScaleKQKRPs[c];

}

if (npm_w + npm_b == VALUE_ZERO && pos.pieces(PAWN)) // Only pawns on the board

{

if (!pos.count<PAWN>(BLACK))

{

assert(pos.count<PAWN>(WHITE) >= 2);

e->scalingFunction[WHITE] = &ScaleKPsK[WHITE];

}

else if (!pos.count<PAWN>(WHITE))

{

assert(pos.count<PAWN>(BLACK) >= 2);

e->scalingFunction[BLACK] = &ScaleKPsK[BLACK];

}

else if (pos.count<PAWN>(WHITE) == 1 && pos.count<PAWN>(BLACK) == 1)

{

// This is a special case because we set scaling functions

// for both colors instead of only one.

e->scalingFunction[WHITE] = &ScaleKPKP[WHITE];

e->scalingFunction[BLACK] = &ScaleKPKP[BLACK];

}

}

// Zero or just one pawn makes it difficult to win, even with a small material

// advantage. This catches some trivial draws like KK, KBK and KNK and gives a

// drawish scale factor for cases such as KRKBP and KmmKm (except for KBBKN).

if (!pos.count<PAWN>(WHITE) && npm_w - npm_b <= BishopValueMg)

e->factor[WHITE] = uint8_t(npm_w < RookValueMg ? SCALE_FACTOR_DRAW :

npm_b <= BishopValueMg ? 4 : 14);

if (!pos.count<PAWN>(BLACK) && npm_b - npm_w <= BishopValueMg)

e->factor[BLACK] = uint8_t(npm_b < RookValueMg ? SCALE_FACTOR_DRAW :

npm_w <= BishopValueMg ? 4 : 14);

// Evaluate the material imbalance. We use PIECE_TYPE_NONE as a place holder

// for the bishop pair "extended piece", which allows us to be more flexible

// in defining bishop pair bonuses.

const int pieceCount[COLOR_NB][PIECE_TYPE_NB] = {

{ pos.count<BISHOP>(WHITE) > 1, pos.count<PAWN>(WHITE), pos.count<KNIGHT>(WHITE),

pos.count<BISHOP>(WHITE) , pos.count<ROOK>(WHITE), pos.count<QUEEN >(WHITE) },

{ pos.count<BISHOP>(BLACK) > 1, pos.count<PAWN>(BLACK), pos.count<KNIGHT>(BLACK),

pos.count<BISHOP>(BLACK) , pos.count<ROOK>(BLACK), pos.count<QUEEN >(BLACK) } };

e->score = (imbalance<WHITE>(pieceCount) - imbalance<BLACK>(pieceCount)) / 16;

return e;

}

} // namespace Material

} // namespace Stockfish