/*
 * canbus_isotp.h
 * ISO-TP (ISO 15765-2) transport layer for CAN bus.
 * Handles multi-frame messaging (> 8 bytes) required by UDS and OBD-II.
 */
#pragma once

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

#ifdef __cplusplus
extern "C" {
#endif

typedef enum {
    ISOTP_OK = 0,
    ISOTP_TIMEOUT,
    ISOTP_OVERFLOW,
    ISOTP_ERROR,
} isotp_status_t;

/*
 * Send an ISO-TP message (blocking).
 * Handles Single Frame for len <= 7, or First Frame + Consecutive Frames.
 * Waits for Flow Control frame from receiver if multi-frame.
 *
 * tx_id: CAN arbitration ID for outgoing frames
 * rx_id: CAN arbitration ID for incoming Flow Control
 * data/len: payload to send
 * timeout_ms: max wait for Flow Control response
 */
isotp_status_t isotp_send(uint32_t tx_id, uint32_t rx_id,
                          const uint8_t *data, size_t len,
                          int timeout_ms);

/*
 * Receive an ISO-TP message (blocking).
 * Reassembles Single Frame or First Frame + Consecutive Frames.
 * Sends Flow Control frame to sender if multi-frame.
 *
 * rx_id: CAN arbitration ID to listen for
 * buf/buf_cap: output buffer
 * out_len: actual received length
 * timeout_ms: max wait time
 */
isotp_status_t isotp_recv(uint32_t rx_id,
                          uint8_t *buf, size_t buf_cap, size_t *out_len,
                          int timeout_ms);

/*
 * Request-Response: send then receive (most common UDS pattern).
 * Combines isotp_send() + isotp_recv() with proper FC handling.
 *
 * tx_id/rx_id: CAN ID pair (e.g. 0x7E0/0x7E8 for ECU diagnostics)
 */
isotp_status_t isotp_request(uint32_t tx_id, uint32_t rx_id,
                             const uint8_t *req, size_t req_len,
                             uint8_t *resp, size_t resp_cap, size_t *resp_len,
                             int timeout_ms);

/*
 * Install ISO-TP RX hook into the CAN driver callback chain.
 * Must be called after can_driver_set_rx_callback() so that the
 * previous callback (sniff/record) is preserved in the chain.
 */
void isotp_install_hook(void);

#ifdef __cplusplus
}
#endif