syntax = "proto3";

package ibc.core.channel.v1;

option go_package = "github.com/cosmos/ibc-go/v9/modules/core/04-channel/types";

import "gogoproto/gogo.proto";
import "ibc/core/client/v1/client.proto";

// Channel defines pipeline for exactly-once packet delivery between specific
// modules on separate blockchains, which has at least one end capable of
// sending packets and one end capable of receiving packets.
message Channel {
  option (gogoproto.goproto_getters) = false;

  // current state of the channel end
  State state = 1;
  // whether the channel is ordered or unordered
  Order ordering = 2;
  // counterparty channel end
  Counterparty counterparty = 3 [(gogoproto.nullable) = false];
  // list of connection identifiers, in order, along which packets sent on
  // this channel will travel
  repeated string connection_hops = 4;
  // opaque channel version, which is agreed upon during the handshake
  string version = 5;
  // upgrade sequence indicates the latest upgrade attempt performed by this channel
  // the value of 0 indicates the channel has never been upgraded
  uint64 upgrade_sequence = 6;
}

// IdentifiedChannel defines a channel with additional port and channel
// identifier fields.
message IdentifiedChannel {
  option (gogoproto.goproto_getters) = false;

  // current state of the channel end
  State state = 1;
  // whether the channel is ordered or unordered
  Order ordering = 2;
  // counterparty channel end
  Counterparty counterparty = 3 [(gogoproto.nullable) = false];
  // list of connection identifiers, in order, along which packets sent on
  // this channel will travel
  repeated string connection_hops = 4;
  // opaque channel version, which is agreed upon during the handshake
  string version = 5;
  // port identifier
  string port_id = 6;
  // channel identifier
  string channel_id = 7;
  // upgrade sequence indicates the latest upgrade attempt performed by this channel
  // the value of 0 indicates the channel has never been upgraded
  uint64 upgrade_sequence = 8;
}

// State defines if a channel is in one of the following states:
// CLOSED, INIT, TRYOPEN, OPEN, FLUSHING, FLUSHCOMPLETE or UNINITIALIZED.
enum State {
  option (gogoproto.goproto_enum_prefix) = false;

  // Default State
  STATE_UNINITIALIZED_UNSPECIFIED = 0 [(gogoproto.enumvalue_customname) = "UNINITIALIZED"];
  // A channel has just started the opening handshake.
  STATE_INIT = 1 [(gogoproto.enumvalue_customname) = "INIT"];
  // A channel has acknowledged the handshake step on the counterparty chain.
  STATE_TRYOPEN = 2 [(gogoproto.enumvalue_customname) = "TRYOPEN"];
  // A channel has completed the handshake. Open channels are
  // ready to send and receive packets.
  STATE_OPEN = 3 [(gogoproto.enumvalue_customname) = "OPEN"];
  // A channel has been closed and can no longer be used to send or receive
  // packets.
  STATE_CLOSED = 4 [(gogoproto.enumvalue_customname) = "CLOSED"];
  // A channel has just accepted the upgrade handshake attempt and is flushing in-flight packets.
  STATE_FLUSHING = 5 [(gogoproto.enumvalue_customname) = "FLUSHING"];
  // A channel has just completed flushing any in-flight packets.
  STATE_FLUSHCOMPLETE = 6 [(gogoproto.enumvalue_customname) = "FLUSHCOMPLETE"];
}

// Order defines if a channel is ORDERED or UNORDERED
enum Order {
  option (gogoproto.goproto_enum_prefix) = false;

  // zero-value for channel ordering
  ORDER_NONE_UNSPECIFIED = 0 [(gogoproto.enumvalue_customname) = "NONE"];
  // packets can be delivered in any order, which may differ from the order in
  // which they were sent.
  ORDER_UNORDERED = 1 [(gogoproto.enumvalue_customname) = "UNORDERED"];
  // packets are delivered exactly in the order which they were sent
  ORDER_ORDERED = 2 [(gogoproto.enumvalue_customname) = "ORDERED"];
}

// Counterparty defines a channel end counterparty
message Counterparty {
  option (gogoproto.goproto_getters) = false;

  // port on the counterparty chain which owns the other end of the channel.
  string port_id = 1;
  // channel end on the counterparty chain
  string channel_id = 2;
}

// Packet defines a type that carries data across different chains through IBC
message Packet {
  option (gogoproto.goproto_getters) = false;

  // number corresponds to the order of sends and receives, where a Packet
  // with an earlier sequence number must be sent and received before a Packet
  // with a later sequence number.
  uint64 sequence = 1;
  // identifies the port on the sending chain.
  string source_port = 2;
  // identifies the channel end on the sending chain.
  string source_channel = 3;
  // identifies the port on the receiving chain.
  string destination_port = 4;
  // identifies the channel end on the receiving chain.
  string destination_channel = 5;
  // actual opaque bytes transferred directly to the application module
  bytes data = 6;
  // block height after which the packet times out
  ibc.core.client.v1.Height timeout_height = 7 [(gogoproto.nullable) = false];
  // block timestamp (in nanoseconds) after which the packet times out
  uint64 timeout_timestamp = 8;
}

// PacketState defines the generic type necessary to retrieve and store
// packet commitments, acknowledgements, and receipts.
// Caller is responsible for knowing the context necessary to interpret this
// state as a commitment, acknowledgement, or a receipt.
message PacketState {
  option (gogoproto.goproto_getters) = false;

  // channel port identifier.
  string port_id = 1;
  // channel unique identifier.
  string channel_id = 2;
  // packet sequence.
  uint64 sequence = 3;
  // embedded data that represents packet state.
  bytes data = 4;
}

// PacketId is an identifier for a unique Packet
// Source chains refer to packets by source port/channel
// Destination chains refer to packets by destination port/channel
message PacketId {
  option (gogoproto.goproto_getters) = false;

  // channel port identifier
  string port_id = 1;
  // channel unique identifier
  string channel_id = 2;
  // packet sequence
  uint64 sequence = 3;
}

// Acknowledgement is the recommended acknowledgement format to be used by
// app-specific protocols.
// NOTE: The field numbers 21 and 22 were explicitly chosen to avoid accidental
// conflicts with other protobuf message formats used for acknowledgements.
// The first byte of any message with this format will be the non-ASCII values
// `0xaa` (result) or `0xb2` (error). Implemented as defined by ICS:
// https://github.com/cosmos/ibc/tree/master/spec/core/ics-004-channel-and-packet-semantics#acknowledgement-envelope
message Acknowledgement {
  // response contains either a result or an error and must be non-empty
  oneof response {
    bytes  result = 21;
    string error  = 22;
  }
}

// Timeout defines an execution deadline structure for 04-channel handlers.
// This includes packet lifecycle handlers as well as the upgrade handshake handlers.
// A valid Timeout contains either one or both of a timestamp and block height (sequence).
message Timeout {
  // block height after which the packet or upgrade times out
  ibc.core.client.v1.Height height = 1 [(gogoproto.nullable) = false];
  // block timestamp (in nanoseconds) after which the packet or upgrade times out
  uint64 timestamp = 2;
}

// Params defines the set of IBC channel parameters.
message Params {
  // the relative timeout after which channel upgrades will time out.
  Timeout upgrade_timeout = 1 [(gogoproto.nullable) = false];
}