#ifndef CHESSSTARS_ENGINE_H
#define CHESSSTARS_ENGINE_H

#include <stdint.h>

#define BOARD_SQUARES 64
#define MAX_HISTORY 120

#define PIECE_NONE 0
#define PIECE_PAWN 1
#define PIECE_KNIGHT 2
#define PIECE_BISHOP 3
#define PIECE_ROOK 4
#define PIECE_QUEEN 5
#define PIECE_KING 6
#define PIECE_COLOR_BIT 0x08

#define COLOR_WHITE 0
#define COLOR_BLACK 1

#define CASTLE_WK 0x01
#define CASTLE_WQ 0x02
#define CASTLE_BK 0x04
#define CASTLE_BQ 0x08

#define RULE_DISABLE_CASTLING 0x01
#define RULE_DISABLE_EN_PASSANT 0x02
#define RULE_IGNORE_CHECK 0x04

#define STATUS_ONGOING 0
#define STATUS_WHITE_WINS 1
#define STATUS_BLACK_WINS 2
#define STATUS_STALEMATE 3

typedef struct {
    uint8_t from;
    uint8_t to;
    uint8_t piece;
    uint8_t flags;
    uint8_t captured;
    uint8_t promo;
    uint8_t reserved0;
    uint8_t reserved1;
} Move;

#define MOVE_FLAG_CAPTURE 0x01
#define MOVE_FLAG_CASTLE_K 0x02
#define MOVE_FLAG_CASTLE_Q 0x04
#define MOVE_FLAG_EN_PASSANT 0x08
#define MOVE_FLAG_PROMOTION 0x10

typedef struct Engine Engine;

typedef int (*ValidateFn)(Engine *e, Move m);
typedef int (*LogFn)(const char *fmt, ...);

struct Engine {
    uint32_t rule_flags;
    int32_t halfmove_clock;
    int32_t fullmove_number;

    uint8_t board[BOARD_SQUARES];
    uint8_t turn;
    uint8_t castling_rights;
    int8_t ep_square;
    uint8_t variant;

    Move history[MAX_HISTORY];
    ValidateFn validate_move;
    int32_t history_count;

    char game_id[40];

    uint8_t _reserved0[28];
    LogFn log_fn;
};

#define ENGINE_LOG_SLOT 130

#define VARIANT_STANDARD 0
#define VARIANT_RELAXED 1

Engine *engine_new(int variant, const char *fen, uint32_t rule_flags, const char *game_id);
void engine_free(Engine *e);

int engine_add_move(Engine *e, Move m);
int engine_is_legal(Engine *e, Move m);
int engine_get_move_at(Engine *e, int32_t index, Move *out);
int32_t engine_history_count(Engine *e);
void engine_get_board(Engine *e, uint8_t out[BOARD_SQUARES]);
int engine_turn(Engine *e);
int engine_status(Engine *e);
int engine_in_check(Engine *e);

Move engine_bot_move(Engine *e, int depth);

int engine_import_replay(Engine *e, const Move *moves, int32_t count);

#endif