#ifndef RADICK_RADAR_PROTOCOL_H
#define RADICK_RADAR_PROTOCOL_H

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

#ifdef __cplusplus
extern "C" {
#endif

/* RD-03D V1 multi-target UART protocol constants. */
#define RD03D_UART_BAUD_RATE       256000U
#define RD03D_MAX_TARGETS          3U
#define RD03D_TARGET_DATA_SIZE     8U
#define RD03D_FRAME_HEADER_SIZE    4U
#define RD03D_FRAME_TAIL_SIZE      2U
#define RD03D_FRAME_SIZE           30U

#define RD03D_CMD_ENABLE_SIZE      14U
#define RD03D_CMD_MULTI_SIZE       12U
#define RD03D_CMD_END_SIZE         12U

extern const uint8_t rd03d_frame_header[RD03D_FRAME_HEADER_SIZE];
extern const uint8_t rd03d_frame_tail[RD03D_FRAME_TAIL_SIZE];
extern const uint8_t rd03d_cmd_enable[RD03D_CMD_ENABLE_SIZE];
extern const uint8_t rd03d_cmd_multi[RD03D_CMD_MULTI_SIZE];
extern const uint8_t rd03d_cmd_end[RD03D_CMD_END_SIZE];

typedef struct {
    int16_t x_mm;
    int16_t y_mm;
    int16_t speed_cm_s;
    uint16_t resolution_mm;
    bool valid;
} rd03d_target_t;

typedef struct {
    rd03d_target_t targets[RD03D_MAX_TARGETS];
} rd03d_frame_t;

/*
 * The parser owns no dynamic memory and is safe to place in static storage or
 * on a task stack. Its fields are public so the same header works in ESP-IDF
 * and small host-side tests without an allocator or opaque platform handle.
 */
typedef struct {
    uint8_t buffer[RD03D_FRAME_SIZE];
    size_t buffered;
    size_t header_matched;
    uint64_t bytes_received;
    uint32_t frames_decoded;
    uint32_t malformed_frames;
} rd03d_parser_t;

typedef void (*rd03d_frame_callback_t)(const rd03d_frame_t *frame, void *context);

/* Decode the RD-03D's unusual sign/magnitude value (bit 15 means positive). */
int16_t rd03d_decode_sign_magnitude(uint8_t low, uint8_t high);

/* Decode one complete frame. Returns false unless both header and tail match. */
bool rd03d_decode_frame(const uint8_t frame[RD03D_FRAME_SIZE], rd03d_frame_t *out);

void rd03d_parser_init(rd03d_parser_t *parser);

/*
 * Feed one byte. A complete decoded frame is copied to out (when non-NULL),
 * and true is returned. Noise and malformed frames are consumed internally.
 */
bool rd03d_parser_push(rd03d_parser_t *parser, uint8_t byte, rd03d_frame_t *out);

/*
 * Feed an arbitrary UART chunk. The callback is invoked once per frame when
 * non-NULL; the return value always reports the number of decoded frames.
 */
size_t rd03d_parser_feed(rd03d_parser_t *parser,
                         const uint8_t *data,
                         size_t length,
                         rd03d_frame_callback_t callback,
                         void *context);

#ifdef __cplusplus
}
#endif

#endif /* RADICK_RADAR_PROTOCOL_H */