/**
 * @file app_ble_proto.h
 * @brief BLE frame protocol frontend (over the rdtss write/notify
 *        characteristics): frame reassembly, CLI request/response transport,
 *        device info query and OTA frame dispatch (see docs/ble_protocol.md).
 *
 * Frame format (little endian):
 *   [0]    SOF = 0xCA
 *   [1]    TYPE
 *   [2]    SEQ
 *   [3:4]  LEN (payload length, LE)
 *   [5..]  PAYLOAD
 *   [end-2..end] CRC16-CCITT (init 0xFFFF, poly 0x1021), LE, over TYPE..PAYLOAD
 *
 * All functions run in the BLE schedule task context only.
 */
#ifndef __APP_BLE_PROTO_H__
#define __APP_BLE_PROTO_H__

#ifdef __cplusplus
extern "C" {
#endif

#include <stdint.h>

/* Frame types */
#define BLE_FRAME_CLI_REQ       0x01    /* phone -> device: one command line */
#define BLE_FRAME_CLI_RSP       0x02    /* device -> phone: response text chunk */
#define BLE_FRAME_CLI_RSP_END   0x03    /* device -> phone: {status u8} */
#define BLE_FRAME_OTA_BEGIN     0x10    /* phone -> device: {size, crc32, version} */
#define BLE_FRAME_OTA_DATA      0x11    /* phone -> device: {offset, data...} */
#define BLE_FRAME_OTA_END       0x12    /* phone -> device: {crc32} */
#define BLE_FRAME_OTA_RSP       0x1F    /* device -> phone: {cmd, status, offset} */
#define BLE_FRAME_INFO_QUERY    0x20    /* phone -> device: {item_id}*n (empty/0xFF = all) */
#define BLE_FRAME_INFO_RSP      0x21    /* device -> phone: TLV {id, len, value}*n */

/* OTA_RSP / generic status codes */
#define BLE_OTA_ST_OK           0
#define BLE_OTA_ST_BAD_FRAME    1
#define BLE_OTA_ST_BAD_STATE    2   /* bad state / bad offset sequence */
#define BLE_OTA_ST_SIZE_TOO_BIG 3
#define BLE_OTA_ST_CRC_FAIL     4
#define BLE_OTA_ST_FLASH_FAIL   5

/**
 * @brief Reset the protocol state machine.
 */
void app_ble_proto_init(void);

/**
 * @brief Build one frame and push it into the ble_up uplink ring.
 *        Used by the CLI frontend and by the OTA/INFO handlers to answer.
 * @return 0 on success, -1 when the frame exceeds the max frame size.
 */
int app_ble_proto_send_frame(uint8_t type, uint8_t seq, const uint8_t* payload, uint16_t len);

/**
 * @brief Feed a received BLE write chunk into the frame reassembler.
 *        Called from the rdtss write indication handler (BLE task context).
 */
void app_ble_proto_rx_bytes(const uint8_t* data, uint16_t len);

/**
 * @brief BLE disconnect hook: drop half-received frame and uplink buffer.
 */
void app_ble_proto_on_disconnect(void);

/**
 * @brief BLE traffic log switch (default off). When on, every complete
 *        RX/TX frame is hex-dumped to the UART via printf, and BLE
 *        connect/disconnect events are printed too.
 */
void app_ble_proto_log_set(uint8_t on);
uint8_t app_ble_proto_log_get(void);

/**
 * @brief Execute one raw CLI command line written to the CLI read/write
 *        characteristic (no frame, no notify). The command output text is
 *        captured into an internal buffer for app_ble_proto_cli_rsp().
 *        Called from the rdtss write indication handler (BLE task context).
 */
void app_ble_proto_cli_exec(const uint8_t* cmd, uint16_t len);

/**
 * @brief Get the output of the last app_ble_proto_cli_exec() call.
 *        Served as the ATT read value of the CLI read/write characteristic.
 */
const uint8_t* app_ble_proto_cli_rsp(uint16_t* out_len);

#ifdef __cplusplus
}
#endif

#endif /* __APP_BLE_PROTO_H__ */