// Directional envelopes and the connection preamble.
//
// The preamble is the fixed, bounded envelope understood before any other
// payload. The first client frame is always PreambleRequest; the first
// server frame is always PreambleResponse. Exact version equality is
// mandatory; the preamble negotiates immutable per-connection ceilings once.
syntax = "proto3";

package vev.wire.v1;

import "command.proto";
import "navigation.proto";
import "picker.proto";
import "session.proto";
import "terminal.proto";

option go_package = "github.com/bnema/vev/internal/protocol/wire";

// ProtocolEpoch identifies the current wire epoch. Bumped only for an
// intentional clean break; ALPN and version checks bind to it. The numeric
// value lives as wire.ProtocolEpoch in Go; it is documented here as the
// schema authority (current value 1).

// PreambleMagic is the fixed 4-byte magic opening every preamble. The
// numeric value lives as wire.PreambleMagic in Go; it is documented here
// as the schema authority (0x56455631, "VEV1").

// PreambleRole names which side sends the preamble.
message PreambleRole {
  // Closed taxonomy: 1 = client, 2 = server.
  uint32 role = 1;
}

// PreambleRequest is the client's first frame on every connection.
message PreambleRequest {
  uint32 magic = 1; // must equal PREAMBLE_MAGIC
  uint32 epoch = 2; // must equal PROTOCOL_EPOCH
  uint32 version = 3; // exact session protocol version
  PreambleRole role = 4; // must be client
  uint64 max_receive_envelope_bytes = 5; // advertised receive ceiling
  uint64 output_data_limit = 6; // advertised Output data ceiling
  uint32 capability_bits = 7; // optional capability flags
}

// PreambleRejectionCode is the closed preamble refusal taxonomy.
message PreambleRejectionCode {
  // Closed taxonomy: 1 = bad magic, 2 = epoch mismatch, 3 = version
  // mismatch, 4 = wrong role, 5 = duplicate preamble, 6 = out of order,
  // 7 = limit refused.
  uint32 code = 1;
}

// PreambleResponse is the server's first frame: acceptance or typed refusal.
message PreambleResponse {
  uint32 magic = 1; // must equal PREAMBLE_MAGIC
  uint32 epoch = 2;
  uint32 version = 3;
  PreambleRole role = 4; // must be server
  uint64 max_receive_envelope_bytes = 5; // effective negotiated ceiling
  uint64 output_data_limit = 6; // effective Output data ceiling
  uint32 capability_bits = 7;
  bool accepted = 8;
  PreambleRejectionCode rejection = 9; // set only when accepted is false
}

// ClientEnvelope is the closed client-to-server union. Exactly one variant
// must be set per envelope; sessionwire rejects empty, duplicate, and
// wrong-direction payloads before generated unmarshal.
message ClientEnvelope {
  // 14 was the one-shot remote_preview_request; 27 was picker_preview_request.
  reserved 14, 27;

  oneof payload {
    Hello hello = 1;
    Input input = 2;
    Resize resize = 3;
    Detach detach = 4;
    Ping ping = 5;
    List list = 6;
    Kill kill = 7;
    Theme theme = 8;
    Ack ack = 9;
    ImagePush image_push = 10;
    ClientNotice client_notice = 11;
    CommandRequest command_request = 12;
    OutputResetRequest output_reset_request = 13;
    RouteAttentionSubscription route_attention_subscription = 15;
    SamePeerSwitchRequest same_peer_switch_request = 16;
    RecentRouteSnapshot recent_route_snapshot = 17;
    RouteNavigationFailure route_navigation_failure = 18;
    SessionCreationFailure session_creation_failure = 19;
    UIFence ui_fence = 20;
    NavigationInventoryRequest navigation_inventory_request = 21;
    NavigationInventoryPublication navigation_inventory_publication = 22;
    NavigationInventoryFailure navigation_inventory_failure = 23;
    PickerClose picker_close = 25;
    PickerSelection picker_selection = 26;
    SuspendAttachment suspend_attachment = 29;
    ActivateAttachment activate_attachment = 30;
    SelectTab select_tab = 31;
    RemotePreviewWatch remote_preview_watch = 32;
    TerminalFocus terminal_focus = 33;
  }
}

// ServerEnvelope is the closed server-to-client union. Exactly one variant
// must be set per envelope.
message ServerEnvelope {
  // 29 and 30 mirror the client-direction attachment request tags; 27 was
  // picker_preview.
  reserved 27, 29, 30;

  oneof payload {
    Welcome welcome = 1;
    ErrorMsg error = 2;
    Output output = 3;
    Detached detached = 4;
    Pong pong = 5;
    Sessions sessions = 6;
    CommandResult command_result = 7;
    AttachTarget attach_target = 8;
    RemotePreview remote_preview = 9;
    CommittedRouteIdentity committed_route_identity = 10;
    RouteNavigationAction route_navigation_action = 11;
    RouteCreateSessionAction route_create_session_action = 12;
    RouteNavigationFailure route_navigation_failure = 13;
    RoutePosition route_position = 14;
    RouteRetired route_retired = 15;
    SamePeerSwitchFailure same_peer_switch_failure = 16;
    UIReceipt ui_receipt = 17;
    UIViewUpdate ui_view_update = 18;
    NavigationInventoryResponse navigation_inventory_response = 19;
    NavigationInventoryDemand navigation_inventory_demand = 20;
    NavigationInventorySelection navigation_inventory_selection = 21;
    PickerOffer picker_offer = 22;
    PickerSnapshot picker_snapshot = 23;
    PickerClosed picker_closed = 24;
    PickerResult picker_result = 25;
    PickerFailure picker_failure = 26;
    AttachmentSuspended attachment_suspended = 31;
    AttachmentActivated attachment_activated = 32;
    KillResult kill_result = 33;
  }
}