syntax = "proto3";

package keyboard.cdc;

// Full protocol schema.
//
// CDC uses:
//   [AA][55][Len][Type][Payload][Checksum]
//
// GATT uses:
//   protobuf(CdcPacketBody)
//
// In this schema, the outer CDC frame is also modeled explicitly so we keep
// one complete protocol definition.

enum CdcPacketType {
  CDC_PACKET_TYPE_UNKNOWN = 0;
  CDC_PACKET_TYPE_HELLO_REQ = 1;
  CDC_PACKET_TYPE_HELLO_RSP = 2;
  CDC_PACKET_TYPE_BITMAP = 16;
  CDC_PACKET_TYPE_FUNCTION_KEY_EVENT = 32;
  CDC_PACKET_TYPE_LED_STATE = 33;
  CDC_PACKET_TYPE_TIME_SYNC = 48;
  CDC_PACKET_TYPE_THEME_RGB = 49;
  CDC_PACKET_TYPE_ACK = 126;
  CDC_PACKET_TYPE_ERROR = 127;
}

enum KeyAction {
  KEY_ACTION_RELEASE = 0;
  KEY_ACTION_PRESS = 1;
}

enum ErrorCode {
  ERROR_CODE_NONE = 0;
  ERROR_CODE_UNKNOWN_TYPE = 1;
  ERROR_CODE_INVALID_LENGTH = 2;
  ERROR_CODE_INVALID_PARAM = 3;
  ERROR_CODE_NOT_READY = 4;
}

message CdcFrame {
  uint32 head1 = 1;
  uint32 head2 = 2;
  uint32 payload_length = 3;
  CdcPacketType type = 4;
  bytes payload = 5;
  uint32 checksum = 6;
}

message CdcPacketBody {
  oneof body {
    HelloReq hello_req = 1;
    HelloRsp hello_rsp = 2;
    Bitmap bitmap = 3;
    FunctionKeyEvent function_key_event = 4;
    LedState led_state = 5;
    TimeSync time_sync = 6;
    ThemeRgb theme_rgb = 7;
    Ack ack = 8;
    Error error = 9;
  }
}

message HelloReq {
  uint32 protocol_version = 1;
}

message HelloRsp {
  uint32 protocol_version = 1;
  uint32 vendor_id = 2;
  uint32 product_id = 3;
  uint32 firmware_major = 4;
  uint32 firmware_minor = 5;
  uint32 capability_flags = 6;
}

message Bitmap {
  bytes usage_bitmap = 1;
}

message FunctionKeyEvent {
  uint32 usage = 1;
  KeyAction action = 2;
}

message LedState {
  uint32 led_mask = 1;
}

message TimeSync {
  uint32 version = 1;
  uint32 flags = 2;
  sint32 timezone_min = 3;
  fixed64 utc_ms = 4;
  fixed32 accuracy_ms = 5;
}

message ThemeRgb {
  uint32 red = 1;
  uint32 green = 2;
  uint32 blue = 3;
}

message Ack {
  uint32 acked_type = 1;
}

message Error {
  uint32 error_type = 1;
  ErrorCode error_code = 2;
}