#include <algorithm> // For std::min

#include <cassert>

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

#include "material.h"

#include "thread.h"

using namespace std;

namespace {

// Polynomial material imbalance parameters

// pair pawn knight bishop rook queen

const int Linear[6] = { 1667, -168, -1027, -166, 238, -138 };

const int QuadraticOurs[][PIECE_TYPE_NB] = {

// OUR PIECES

// pair pawn knight bishop rook queen

{ 0 }, // Bishop pair

{ 40, 2 }, // Pawn

{ 32, 255, -3 }, // Knight OUR PIECES

{ 0, 104, 4, 0 }, // Bishop

{ -26, -2, 47, 105, -149 }, // Rook

{-185, 24, 122, 137, -134, 0 } // Queen

};

const int QuadraticTheirs[][PIECE_TYPE_NB] = {

// THEIR PIECES

// pair pawn knight bishop rook queen

{ 0 }, // Bishop pair

{ 36, 0 }, // Pawn

{ 9, 63, 0 }, // Knight OUR PIECES

{ 59, 65, 42, 0 }, // Bishop

{ 46, 39, 24, -24, 0 }, // Rook

{ 101, 100, -37, 141, 268, 0 } // Queen

};

// 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_KBPsKs(const Position& pos, Color us) {

}

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>

int 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;

e->gamePhase = pos.game_phase();

// 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 = pos.this_thread()->endgames.probe<Value>(key)) != nullptr)

return e;

for (Color c = WHITE; c <= BLACK; ++c)

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?

EndgameBase<ScaleFactor>* sf;

if ((sf = pos.this_thread()->endgames.probe<ScaleFactor>(key)) != nullptr)

{

e->scalingFunction[sf->strong_side()] = 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; c <= BLACK; ++c)

{

if (is_KBPsKs(pos, c))

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

else if (is_KQKRPs(pos, c))

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

}

Value npm_w = pos.non_pawn_material(WHITE);

Value npm_b = pos.non_pawn_material(BLACK);

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);

if (pos.count<PAWN>(WHITE) == 1 && npm_w - npm_b <= BishopValueMg)

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

if (pos.count<PAWN>(BLACK) == 1 && npm_b - npm_w <= BishopValueMg)

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

// 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->value = int16_t((imbalance<WHITE>(PieceCount) - imbalance<BLACK>(PieceCount)) / 16);

return e;

}

} // namespace Material