// Copyright 2021 EngFlow, Inc. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

syntax = "proto3";

package engflow.eventstore.v1;

import "engflow/api/options.proto";
import "google/api/field_behavior.proto";
import "engflow/eventstore/v1/build_event.proto";

option go_package = "github.com/EngFlow/engflowapis/go/engflow/eventstore/v1;eventstorev1";

option java_multiple_files = true;
option java_outer_classname = "EventStoreProtos";
option java_package = "com.engflow.eventstore.v1.proto";

// This is the interface used to retrieve raw event streams from the EventStore
// service.
service EventStore {
  option (engflow.api.engflow_service) = {
    launch_stage: GENERAL_AVAILABILITY

    availability {
      product: "platform"

      since { major: 2 minor: 2 patch: 0 }
    }
  };

  // Retrieves a BES stream with the given build ID.
  //
  // Note that this is conceptually different from `EventStore/StreamInvocation`
  // as the latter only streams events from a single invocation while this one
  // may stream events from multiple (retried) invocations.
  //
  // The first event is guaranteed to be of type `BuildEnqueued`.
  //
  // An error will be reported in the following cases:
  //   * `INVALID_ARGUMENT`: The request is invalid (e.g., did not specify an
  //                         build ID).
  //   * `NOT_FOUND`: A build with the specified build ID does not exist.
  rpc GetBuild(GetBuildRequest) returns (stream StreamedBuildEvent) {
    option (engflow.api.engflow_method) = {
      launch_stage: EARLY_ACCESS

      availability {
        product: "platform"

        since { major: 2 minor: 36 patch: 0 }
      }

      required_permission: "eventstore:GetBuild"
    };
  }

  // Retrieves a BES stream with the given invocation ID.
  //
  // The first event is guaranteed to be of type `InvocationAttemptStarted`.
  //
  // An error will be reported in the following cases:
  //   * `INVALID_ARGUMENT`: The request is invalid (e.g., did not specify an
  //                         invocation ID).
  //   * `NOT_FOUND`: A build with the specified invocation ID does not exist.
  rpc GetInvocation(GetInvocationRequest) returns (stream StreamedBuildEvent) {
    option (engflow.api.engflow_method) = {
      launch_stage: GENERAL_AVAILABILITY

      availability {
        product: "platform"

        since { major: 2 minor: 0 patch: 0 }
      }

      required_permission: "eventstore:GetInvocation"
    };
  }
}

// Wrapper around `ReplayMode` to keep enum scoped.
message ReplayModeOptions {
  enum ReplayMode {
    // Replay events until the stream is complete. If the stream is ongoing,
    // then this replays events from storage until the reader is caught up with
    // the writer, and then continues replaying events live. If the writer goes
    // away for some reason, this hangs until the stream times out. When
    // replaying a stream from storage that was never completed, this returns an
    // exception after the last event.
    UNTIL_COMPLETE = 0;

    reserved 1;  // Used for `UNTIL_COMPLETE` in an old version of the API.

    // Replay events until we are caught up with the writer and then stop. If
    // the storage contains an incomplete stream, then this silently returns
    // after the last event that could be successfully read from storage.
    STOP_AFTER_LAST_KNOWN = 2;
  }
}

// A request message for `EventStore/GetBuild`.
message GetBuildRequest {
  // The instance of the execution system used to run the build.
  string instance_name = 1;

  // The ID of the build to retrieve.
  //
  // *MUST* follow the following grammar:
  //
  // ```
  // <stream-id>            -> (<namespace>)<uuid>
  // <namespace>            -> <identifier><namespace-separator>(<namespace>)
  // <uuid>                 -> A RFC 4122-compliant UUID.
  // <namespace-separator>  -> /
  // <identifier>           -> <alphanum>((<dash>)<identifier>)
  // <alphanum>             -> [a-zA-Z0-9]
  // <dash>                 -> -
  // ```
  string build_id = 2 [(google.api.field_behavior) = REQUIRED];

  // A token that allows reading a stream of build events starting with an
  // specific event.
  //
  // Clients *MUST NOT* assume any specific format of this field.
  optional string continuation_token = 3
      [(google.api.field_behavior) = OPTIONAL];
}

// A request message for `EventStore/GetInvocation`.
message GetInvocationRequest {
  // The instance of the execution system used to run the invocation.
  string instance_name = 1;

  // The ID of the invocation to retrieve.
  //
  // Must be an RFC 4122-compliant UUID.
  string invocation_id = 2 [(google.api.field_behavior) = REQUIRED];

  // A token that allows reading a stream of invocation events starting with an
  // specific event.
  //
  // Clients *MUST NOT* assume any specific format of this field.
  optional string continuation_token = 3
      [(google.api.field_behavior) = OPTIONAL];

  // The mode the server should use to replay the stream.
  ReplayModeOptions.ReplayMode replay_mode = 4
      [(google.api.field_behavior) = REQUIRED];
}

message StreamedBuildEvent {
  // Indicates that this is the last event of the stream.
  bool is_last = 1;

  // A token that allows starting a stream of invocation events starting with
  // the event immediately following the current one.
  //
  // Clients *MUST NOT* assume any specific format of this field.
  string continuation_token = 2 [(google.api.field_behavior) = REQUIRED];

  // The actual build event.
  //
  // This may be null iff `is_last` is true and client provided a continuation
  // token that would continue the stream after the last event of the BES
  // stream.
  optional BuildProgressEvent event = 3
      [(google.api.field_behavior) = OPTIONAL];

  // The principal name who initiated the build.
  string principal = 4;
}