#ifndef ORIN_CAN_H
#define ORIN_CAN_H

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

/*
 * orin_can — Orin↔FC CAN protocol driver (Issue #674).
 *
 * Standard 11-bit CAN IDs on CAN2, FIFO0.
 *
 * Orin → FC commands:
 *   0x300 HEARTBEAT : uint32 sequence counter (4 bytes)
 *   0x301 DRIVE     : int16 speed (−1000..+1000), int16 steer (−1000..+1000)
 *   0x302 MODE      : uint8 mode (0=RC_MANUAL, 1=ASSISTED, 2=AUTONOMOUS)
 *   0x303 ESTOP     : uint8 action (1=ESTOP, 0=CLEAR)
 *
 * FC → Orin telemetry (broadcast at ORIN_TLM_HZ):
 *   0x400 FC_STATUS : int16 pitch_x10, int16 motor_cmd, uint16 vbat_mv,
 *                     uint8 balance_state, uint8 flags [bit0=estop, bit1=armed]
 *   0x401 FC_VESC   : int16 left_rpm_x10 (RPM/10), int16 right_rpm_x10,
 *                     int16 left_current_x10, int16 right_current_x10
 *
 * Balance independence: if no Orin heartbeat for ORIN_HB_TIMEOUT_MS, the FC
 * continues balancing in-place — Orin commands are simply not injected.
 * The balance PID loop runs entirely on Mamba and never depends on Orin.
 */

/* ---- Orin → FC command IDs ---- */
#define ORIN_CAN_ID_HEARTBEAT   0x300u
#define ORIN_CAN_ID_DRIVE       0x301u
#define ORIN_CAN_ID_MODE        0x302u
#define ORIN_CAN_ID_ESTOP       0x303u

/* ---- FC → Orin telemetry IDs ---- */
#define ORIN_CAN_ID_FC_STATUS   0x400u
#define ORIN_CAN_ID_FC_VESC     0x401u

/* ---- Timing ---- */
#define ORIN_HB_TIMEOUT_MS      500u   /* Orin offline after 500 ms without any frame */
#define ORIN_TLM_HZ             10u    /* FC → Orin broadcast rate (Hz) */

/* ---- Volatile state updated by orin_can_on_frame(), read by main loop ---- */
typedef struct {
    volatile int16_t  speed;           /* DRIVE: −1000..+1000 */
    volatile int16_t  steer;           /* DRIVE: −1000..+1000 */
    volatile uint8_t  mode;            /* MODE:  robot_mode_t value */
    volatile uint8_t  drive_updated;   /* set on DRIVE, cleared by main */
    volatile uint8_t  mode_updated;    /* set on MODE,  cleared by main */
    volatile uint8_t  estop_req;       /* set on ESTOP(1), cleared by main */
    volatile uint8_t  estop_clear_req; /* set on ESTOP(0), cleared by main */
    volatile uint32_t last_rx_ms;      /* HAL_GetTick() of last received frame */
} OrinCanState;

extern volatile OrinCanState orin_can_state;

/* ---- FC → Orin broadcast payloads (packed, 8 bytes each) ---- */

typedef struct __attribute__((packed)) {
    int16_t  pitch_x10;      /* pitch degrees × 10 */
    int16_t  motor_cmd;      /* balance PID output −1000..+1000 */
    uint16_t vbat_mv;        /* battery voltage (mV) */
    uint8_t  balance_state;  /* BalanceState: 0=DISARMED,1=ARMED,2=TILT_FAULT */
    uint8_t  flags;          /* bit0=estop_active, bit1=armed */
} orin_can_fc_status_t;  /* 8 bytes */

typedef struct __attribute__((packed)) {
    int16_t left_rpm_x10;        /* left  wheel RPM / 10 (±32767 × 10 = ±327k RPM) */
    int16_t right_rpm_x10;       /* right wheel RPM / 10 */
    int16_t left_current_x10;    /* left  phase current × 10 (A) */
    int16_t right_current_x10;   /* right phase current × 10 (A) */
} orin_can_fc_vesc_t;  /* 8 bytes */

/* ---- API ---- */

/*
 * orin_can_init() — zero state, register orin_can_on_frame as std_cb with
 * can_driver.  Call after can_driver_init().
 */
void orin_can_init(void);

/*
 * orin_can_on_frame(std_id, data, len) — dispatched by can_driver for each
 * standard-ID frame in FIFO0.  Updates orin_can_state.
 */
void orin_can_on_frame(uint16_t std_id, const uint8_t *data, uint8_t len);

/*
 * orin_can_is_alive(now_ms) — true if a frame from Orin arrived within
 * ORIN_HB_TIMEOUT_MS of now_ms.
 */
bool orin_can_is_alive(uint32_t now_ms);

/*
 * orin_can_broadcast(now_ms, status, vesc) — rate-limited broadcast of
 * FC_STATUS (0x400) and FC_VESC (0x401) at ORIN_TLM_HZ (10 Hz).
 * Safe to call every ms; internally rate-limited.
 */
void orin_can_broadcast(uint32_t now_ms,
                        const orin_can_fc_status_t *status,
                        const orin_can_fc_vesc_t   *vesc);

#endif /* ORIN_CAN_H */