#ifndef __BOARD_H_INC
#define __BOARD_H_INC

#include "Types.h"
#include "Panic.h"
#include "Move.h"

#define BOARD_DEFAULT_VALUE { \
	W_ROOK, W_KNGT, W_BSHP, W_QUEN, W_KING, W_BSHP, W_KNGT, W_ROOK, 0, 0, 0, 0, 0, 0, 0, 0, \
	W_PAWN, W_PAWN, W_PAWN, W_PAWN, W_PAWN, W_PAWN, W_PAWN, W_PAWN, 0, 0, 0, 0, 0, 0, 0, 0, \
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
	B_PAWN, B_PAWN, B_PAWN, B_PAWN, B_PAWN, B_PAWN, B_PAWN, B_PAWN, 0, 0, 0, 0, 0, 0, 0, 0, \
	B_ROOK, B_KNGT, B_BSHP, B_QUEN, B_KING, B_BSHP, B_KNGT, B_ROOK, 0, 0, 0, 0, 0, 0, 0, 0, \
};

// 0x88-fill definitions
#define PTR_SIDE_AND_CASTLERIGHT 0x08 //byte (1=side, 2,4=white castle, 8,16=black)
// CAN FILL 0x09
#define PTR_W_KING 0x0A // byte (points to index or maybe 64-arr index)
#define PTR_B_KING 0x0B // (PTR_W_KING | COLOR or PTR_W_KING + COLOR)
#define PTR_ZOBRIST 0x0C // 4 bytes
// 0x0D
// 0x0E
// 0x0F

#define PTR_ENPASSANT 0x18
#define PTR_REVMOV 0x19
// free space

#define PTR_UNMOVE_START 0x28
#define PTR_UNMOVE_LAST 0x7F

byte field[128];
byte PTR_UNMOVE;

const byte field_default_value[] PROGMEM = BOARD_DEFAULT_VALUE;

void board_init() {
	for(int i = 0; i < 128; i++) {
		field[i] = pgm_read_byte_near(field_default_value + i);
	}
	PTR_UNMOVE = PTR_UNMOVE_START;
	field[PTR_SIDE_AND_CASTLERIGHT] = 0b11110; // all castle rights allowed, white to move
	field[PTR_W_KING] = 0x04; // e1
	field[PTR_B_KING] = 0x74; // e8
	long* zob = (long*)&field[PTR_ZOBRIST];
	*zob = 0xDEADBEEF;
}



struct Unmove {
	byte sq_from;	// 0b(1kingside_castle?)(3rank)(1queenside_castle?)(3file)
	byte sq_to;	// 0b(1promoted?)(3rank)(1ep_capture?)(3file)
	byte captured;	// 0b(4enpassantinfo)(1color)(3piecetype)
	byte revmov;	// 8bit integer
};

bool black_moving() {
	return field[PTR_SIDE_AND_CASTLERIGHT] & 0x1;
}

unsigned long get_zobrist() {
	long* addr = (long*) &field[PTR_ZOBRIST];
	return *addr;
}

void reset_unmake_stack() {
	PTR_UNMOVE = PTR_UNMOVE_START;
}

void next_unmove() {
	PTR_UNMOVE++;
	if(PTR_UNMOVE > PTR_UNMOVE_LAST) {
		panic(F("Unmove stack overflow"));
	}
	if(!(PTR_UNMOVE & 0x8)) {
		PTR_UNMOVE += 0x8;
	}
}
void prev_unmove() {
	PTR_UNMOVE--;
	if(PTR_UNMOVE < PTR_UNMOVE_START) {
		panic(F("Unmaking from empty stack"));
	}
	if(!(PTR_UNMOVE & 0x8)) {
		PTR_UNMOVE -= 0x8;
	}
}
void store_unmove(Unmove u) {
	byte *ub = (byte*) &u;
	for(byte i = 0; i < sizeof(u); i++) {
		field[PTR_UNMOVE] = ub[i];
		next_unmove();
	}
}
Unmove read_unmove() {
	Unmove u;
	byte* ptr = (byte*) &u;
	for(int i = sizeof(u) - 1; i >= 0; i--) {
		prev_unmove();
		ptr[i] = field[PTR_UNMOVE];
		#ifdef _ACF_CLEAR_UNMOVE
			field[PTR_UNMOVE] = 0;
		#endif
	}
	return u;
}


void print() {
	Serial.println(F("BOARD:"));
	for(char i = 7; i >= 0; i--) {
		for(byte j = 0; j < 16; j++) {
			if(j == 8)
				Serial.print(F("| "));
			Serial.print(field[i*16 + j], HEX);
			Serial.print(F(" "));
		}
		Serial.println();
	}
}

void make(Move m) {
	// TODO zobrist?

	// fill unmove struct with basic data
	Unmove u;
	u.revmov = field[PTR_REVMOV];
	u.captured = field[m.sq_to] | (field[PTR_ENPASSANT] << 4);
	u.sq_from = m.sq_from;
	u.sq_to = m.sq_to;

	byte piece_type = field[m.sq_from] & 0x7;
	byte color = black_moving();

	if(field[m.sq_to] || piece_type == W_PAWN) {
		field[PTR_REVMOV] = 0;
	} else {
		field[PTR_REVMOV]++;
	}

	// Calculate the move 'amount' (unique signature for dx,dy)
	int sq_diff = (int)m.sq_to - (int)m.sq_from;
	int sq_diff_abs = abs(sq_diff);


	// TODO test the castling code more extensively
	// Handle castling
	if(piece_type == W_KING && sq_diff_abs == 2) {
		// We are castling! After all, a king cannot move
		// more than one position except when castling.
		// Since we don't care about legality; just do it
		byte castle_source = (color ? 0x70 : 0x0);
		if(sq_diff == 2) {
			castle_source += 0x7;
		}
		byte castle_target = m.sq_from + (sq_diff/2);
		field[castle_target] = field[castle_source];
		field[castle_source] = P_EMPTY;
	}

	// Handle castling rights
	// First store the current rights in the unmove
	byte our_rights = field[PTR_SIDE_AND_CASTLERIGHT] >> (color ? 3 : 1);
	if(our_rights & 0b10) // kingside allowed
		u.sq_from |= 0x80;
	if(our_rights & 0b01) // queenside allowed
		u.sq_from |= 0x08;
	// We are doing the simple way:
	// unset it any time a move is made from the original position.
	if(m.sq_from == 0x00) // white queenside rook
		field[PTR_SIDE_AND_CASTLERIGHT] &= ~0b00010;
	else if(m.sq_from == 0x07) // white kingside rook
		field[PTR_SIDE_AND_CASTLERIGHT] &= ~0b00100;
	else if(m.sq_from == 0x04) // white king
		field[PTR_SIDE_AND_CASTLERIGHT] &= ~0b00110;
	else if(m.sq_from == 0x70) // black queenside rook
		field[PTR_SIDE_AND_CASTLERIGHT] &= ~0b01000;
	else if(m.sq_from == 0x77) // black kingside rook
		field[PTR_SIDE_AND_CASTLERIGHT] &= ~0b10000;
	else if(m.sq_from == 0x74) // black king
		field[PTR_SIDE_AND_CASTLERIGHT] &= ~0b11000;

	// TODO: test enpassant code more than basics

	// handle enpassant capture
	if(
		field[PTR_ENPASSANT] &&
		piece_type == W_PAWN &&
		(m.sq_to & 0x7) == (field[PTR_ENPASSANT] & 0x7) &&
		(m.sq_to & 0x70) == (color ? 0x20 : 0x50)
	) {
		// all EP-conditions are met
		// therefore, delete the EP-vurnerable pawn
		byte ep_field = m.sq_to + (color ? 16 : -16);
		field[ep_field] = P_EMPTY;
		// also put information that we did an EP-capture
		u.sq_to |= 0x08;
	}

	// handle enpassant setup (double pawn move)
	if(
		piece_type == W_PAWN &&
		sq_diff_abs == 32
	) {
		// we are doing a pawn double-move.
		// therefore, it allows enpassant in the next move.
		field[PTR_ENPASSANT] = 0b1000 | (m.sq_from & 0x7);
	} else {
		// no enpassant in the next turn.
		field[PTR_ENPASSANT] = 0;
	}

	// are we promoting?
	byte new_val = m.pc_prom & 0b1111;
	if(m.pc_prom != P_EMPTY) {
		// promoting; indicate this in the sq_to byte in unmove.
		field[m.sq_to] = m.pc_prom;
		u.sq_to |= 0x80;
	} else {
		// not promoting; so keep the same piece type
		field[m.sq_to] = field[m.sq_from];
	}
	// then delete the original copy.
	field[m.sq_from] = P_EMPTY;

	// Switch sides
	field[PTR_SIDE_AND_CASTLERIGHT] ^= 0x01;

	store_unmove(u);
}

void unmake() {
	Unmove u = read_unmove();
	field[PTR_REVMOV] = u.revmov;

	byte sq_from = u.sq_from & 0x77;
	byte sq_to = u.sq_to & 0x77;
	byte prom_ep_capt = u.sq_to & 0x88;


	if(prom_ep_capt == 0) {
		// regular move
		field[sq_from] = field[sq_to];
	} else if (prom_ep_capt == 0x80) {
		// piece was promoted
		// so the source is a pawn
		field[sq_from] = W_PAWN | (field[sq_to] & 0b1000);
	} else if (prom_ep_capt == 0x08) {
		// we did an enpassant capture
		byte ep_sq = (sq_to & 0x07) | (sq_from & 0x70);
		field[ep_sq] = W_PAWN | black_moving() << 3;
		// also undo the regular move
		field[sq_from] = field[sq_to];
	}

	byte castleright_offset = 3 - 2*black_moving();
	if(u.sq_from & 0x80) {
		// restore king side castling rights
		field[PTR_SIDE_AND_CASTLERIGHT] |= 0b10 << castleright_offset;
	}
	if(u.sq_from & 0x08) {
		field[PTR_SIDE_AND_CASTLERIGHT] |= 0b01 << castleright_offset;
	}

	int sq_diff = (int)sq_to - (int)sq_from;
	int sq_diff_abs = abs(sq_diff);
	if((field[sq_from] & 0x7) == W_KING && sq_diff_abs == 2) {
		// we castled
		byte castle_source = 0x70*!black_moving();
		if(sq_diff == 2) {
			castle_source += 0x7;
		}
		byte castle_target = sq_from + (sq_diff/2);
		// move rook back to original position
		field[castle_source] = field[castle_target];
		// and clear where it was put
		field[castle_target] = P_EMPTY;
	}


	field[sq_to] = u.captured & 0b1111;

	field[PTR_SIDE_AND_CASTLERIGHT] ^= 0x01;
	field[PTR_ENPASSANT] = u.captured >> 4;
}


#endif