/*
 * canbus_uds.h
 * UDS (ISO 14229) diagnostic services over ISO-TP.
 */
#pragma once

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

#ifdef __cplusplus
extern "C" {
#endif

/* ============================================================
 * UDS Service IDs
 * ============================================================ */
#define UDS_DIAG_SESSION_CTRL    0x10
#define UDS_ECU_RESET            0x11
#define UDS_CLEAR_DTC            0x14
#define UDS_READ_DTC_INFO        0x19
#define UDS_READ_DATA_BY_ID      0x22
#define UDS_READ_MEM_BY_ADDR     0x23
#define UDS_SECURITY_ACCESS      0x27
#define UDS_COMM_CTRL            0x28
#define UDS_WRITE_DATA_BY_ID     0x2E
#define UDS_IO_CTRL              0x2F
#define UDS_ROUTINE_CTRL         0x31
#define UDS_REQUEST_DOWNLOAD     0x34
#define UDS_REQUEST_UPLOAD       0x35
#define UDS_TRANSFER_DATA        0x36
#define UDS_TRANSFER_EXIT        0x37
#define UDS_TESTER_PRESENT       0x3E

/* Session types */
#define UDS_SESSION_DEFAULT      0x01
#define UDS_SESSION_PROGRAMMING  0x02
#define UDS_SESSION_EXTENDED     0x03

/* Negative Response Codes */
#define UDS_NRC_GENERAL_REJECT       0x10
#define UDS_NRC_SERVICE_NOT_SUPPORTED 0x11
#define UDS_NRC_SUBFUNCTION_NOT_SUPPORTED 0x12
#define UDS_NRC_INCORRECT_LENGTH     0x13
#define UDS_NRC_RESPONSE_PENDING     0x78
#define UDS_NRC_SECURITY_ACCESS_DENIED 0x33
#define UDS_NRC_INVALID_KEY          0x35
#define UDS_NRC_EXCEEDED_ATTEMPTS    0x36
#define UDS_NRC_CONDITIONS_NOT_MET   0x22

/* ============================================================
 * UDS Context
 * ============================================================ */

typedef struct {
    uint32_t tx_id;             /* Request CAN ID (e.g. 0x7E0) */
    uint32_t rx_id;             /* Response CAN ID (e.g. 0x7E8) */
    int      timeout_ms;        /* Response timeout */
    uint8_t  session;           /* Current session type */
    bool     security_unlocked;
} uds_ctx_t;

/* ============================================================
 * High-Level UDS API
 * ============================================================ */

/* DiagnosticSessionControl (0x10) */
int uds_diagnostic_session(uds_ctx_t *ctx, uint8_t session_type);

/* TesterPresent (0x3E) — keep-alive */
int uds_tester_present(uds_ctx_t *ctx);

/* ReadDataByIdentifier (0x22) — returns data length or -1 */
int uds_read_data_by_id(uds_ctx_t *ctx, uint16_t did,
                        uint8_t *out, size_t cap);

/* SecurityAccess (0x27) — request seed */
int uds_security_access_seed(uds_ctx_t *ctx, uint8_t level,
                             uint8_t *seed, size_t *seed_len);

/* SecurityAccess (0x27) — send key */
int uds_security_access_key(uds_ctx_t *ctx, uint8_t level,
                            const uint8_t *key, size_t key_len);

/* ReadMemoryByAddress (0x23) — returns data length or -1 */
int uds_read_memory(uds_ctx_t *ctx, uint32_t addr, uint16_t size,
                    uint8_t *out);

/* Raw UDS request — returns response length or -1 */
int uds_raw_request(uds_ctx_t *ctx,
                    const uint8_t *req, size_t req_len,
                    uint8_t *resp, size_t resp_cap, size_t *resp_len);

/* ECU discovery: send TesterPresent to 0x7E0-0x7EF, report responders */
int uds_scan_ecus(uint32_t *found_ids, int max_ecus);

/* Get human-readable NRC name */
const char *uds_nrc_name(uint8_t nrc);

#ifdef __cplusplus
}
#endif