#pragma once
#include <stdint.h>
#include <stdbool.h>

#define FILE_A 0x0101010101010101ULL
#define FILE_B 0x0202020202020202ULL
#define FILE_C 0x0404040404040404ULL
#define FILE_D 0x0808080808080808ULL
#define FILE_E 0x1010101010101010ULL
#define FILE_F 0x2020202020202020ULL
#define FILE_G 0x4040404040404040ULL
#define FILE_H 0x8080808080808080ULL

#define RANK_1 0x00000000000000FFULL
#define RANK_2 0x000000000000FF00ULL
#define RANK_3 0x0000000000FF0000ULL
#define RANK_4 0x00000000FF000000ULL
#define RANK_5 0x000000FF00000000ULL
#define RANK_6 0x0000FF0000000000ULL
#define RANK_7 0x00FF000000000000ULL
#define RANK_8 0xFF00000000000000ULL

#define SET_BIT(bb, sq)     ((bb) |= (1ULL << (sq)))
#define CLEAR_BIT(bb, sq)   ((bb) &= ~(1ULL << (sq)))
#define GET_BIT(bb, sq)     ((bb) & (1ULL << (sq)))
#define TOGGLE_BIT(bb, sq)  ((bb) ^= (1ULL << (sq)))

// King castling helpers.
#define BB(sq) (1ULL << (sq))

// a1 = 0, h8 = 63 (rank*8 + file)
enum Square {
    A1,B1,C1,D1,E1,F1,G1,H1,
    A2,B2,C2,D2,E2,F2,G2,H2,
    A3,B3,C3,D3,E3,F3,G3,H3,
    A4,B4,C4,D4,E4,F4,G4,H4,
    A5,B5,C5,D5,E5,F5,G5,H5,
    A6,B6,C6,D6,E6,F6,G6,H6,
    A7,B7,C7,D7,E7,F7,G7,H7,
    A8,B8,C8,D8,E8,F8,G8,H8
};

#define WK_EMPTY_MASK (BB(F1) | BB(G1))
#define WQ_EMPTY_MASK (BB(B1) | BB(C1) | BB(D1))
#define BK_EMPTY_MASK (BB(F8) | BB(G8))
#define BQ_EMPTY_MASK (BB(B8) | BB(C8) | BB(D8))

// squares king is on / passes / lands (use for attacked-squares test later)
#define WK_THRU_MASK  (BB(E1) | BB(F1) | BB(G1))
#define WQ_THRU_MASK  (BB(E1) | BB(D1) | BB(C1))
#define BK_THRU_MASK  (BB(E8) | BB(F8) | BB(G8))
#define BQ_THRU_MASK  (BB(E8) | BB(D8) | BB(C8))

// king target squares
#define WK_TO G1
#define WQ_TO C1
#define BK_TO G8
#define BQ_TO C8


enum Color { WHITE = 0, BLACK = 1, BOTH = 2 };
enum Piece {
    P, N, B, R, Q, K,   // 0..5 white
    p, n, b, r, q, k    // 6..11 black
};

enum Castling {
    CASTLE_WK = 1 << 0,
    CASTLE_WQ = 1 << 1,
    CASTLE_BK = 1 << 2,
    CASTLE_BQ = 1 << 3
};

enum MoveFlags {
    MF_NONE        = 0,
    MF_CAPTURE     = 1 << 0,
    MF_PROMO       = 1 << 1,
    MF_ENPASSANT   = 1 << 2,
    MF_CASTLE      = 1 << 3,
    MF_DOUBLE_PUSH = 1 << 4,
};

struct Move {
    uint16_t from;
    uint16_t to;
    uint8_t  piece;
    uint8_t  promo;
    uint8_t  flags;  
};

struct Board {
    uint64_t pieces[12];    // Each set of pieces get a bitboard for each player.
    uint64_t occ[3];        // Color occupancy bitboards.

    uint64_t king_square[2];

    uint8_t castling_rights;
    int ep_square;
    enum Color side_to_move;

    int halfmove_clock;
    int fullmove_number;
};

void create_knight_attack_cache();
void create_pawn_attack_cache();
void create_king_attack_cache();
void print_board();
void gen_white_pawn_quiet_pushes(const struct Board *board, struct Move *moves, int *count);
void gen_black_pawn_quiet_pushes(const struct Board *board, struct Move *moves, int *count);
void gen_white_pawn_push_promotions(const struct Board *board, struct Move *moves, int *count);
void gen_black_pawn_push_promotions(const struct Board *board, struct Move *moves, int *count);
void gen_white_pawn_captures(const struct Board *board, struct Move *moves, int *count);
void gen_black_pawn_captures(const struct Board *board, struct Move *moves, int *count);
void gen_white_pawn_capture_promotions(const struct Board *board, struct Move *moves, int *count);
void gen_black_pawn_capture_promotions(const struct Board *board, struct Move *moves, int *count);
int gen_pseudo_moves(const struct Board *board, struct Move *out, bool captures_only);