// SPDX-FileCopyrightText: Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
// SPDX-License-Identifier: Apache-2.0

syntax = "proto3";

package openshell.gateway_interceptor.v1;

import "google/protobuf/struct.proto";
import "extension.proto";
import "openshell.proto";

// GatewayInterceptor lets an external governance service evaluate gateway
// control-plane operations after OpenShell admission and before or after the
// gateway applies the operation.
service GatewayInterceptor {
  // Describe returns the interceptor manifest and declared bindings.
  rpc Describe(DescribeRequest) returns (InterceptorManifest);

  // SnapshotProviderProfiles returns the interceptor's current provider
  // profile snapshot when the manifest advertises provider_profiles = true.
  rpc SnapshotProviderProfiles(ProviderProfileSnapshotRequest)
      returns (ProviderProfileSnapshot);

  // Evaluate returns an allow, deny, or mutation decision for one operation
  // phase.
  rpc Evaluate(InterceptorEvaluation) returns (InterceptorResult);
}

message DescribeRequest {
  // Gateway protocol metadata. Interceptors must reject unmet requirements.
  openshell.extension.v1.PeerMetadata gateway = 1;
}

message ProviderProfileSnapshotRequest {}

enum GatewayInterceptorPhase {
  GATEWAY_INTERCEPTOR_PHASE_UNSPECIFIED = 0;
  GATEWAY_INTERCEPTOR_PHASE_MODIFY_OPERATION = 2;
  GATEWAY_INTERCEPTOR_PHASE_VALIDATE = 3;
  GATEWAY_INTERCEPTOR_PHASE_POST_COMMIT = 4;
}

message InterceptorEvaluation {
  // Configured interceptor instance name.
  string interceptor_name = 1;
  // Manifest binding id selected for this evaluation.
  string binding_id = 2;
  // Public gRPC service name, e.g. "openshell.v1.OpenShell".
  string service = 3;
  // Public gRPC method name, e.g. "CreateSandbox".
  string method = 4;
  // Caller identity summary. Values are intentionally non-secret.
  map<string, string> principal = 5;

  // Exactly one phase payload is set for each evaluation.
  oneof phase {
    // Evaluation that may modify the prepared gateway operation.
    ModifyOperationEvaluation modify_operation = 6;
    // Evaluation that may reject, but not mutate, the prepared operation.
    ValidateEvaluation validate = 7;
    // Evaluation after the gateway operation has completed successfully.
    PostCommitEvaluation post_commit = 8;
  }
}

message ModifyOperationEvaluation {
  // Gateway-prepared operation the gateway proposes to execute.
  google.protobuf.Struct proposed_operation = 1;
}

message ValidateEvaluation {
  // Gateway-prepared operation after earlier interceptor modifications.
  google.protobuf.Struct proposed_operation = 1;
  // Optional read-only gateway state loaded before applying the operation.
  google.protobuf.Struct current_state = 2;
}

message PostCommitEvaluation {
  // Protobuf JSON-shaped response returned by the committed gateway operation.
  google.protobuf.Struct committed_response = 1;
}

message InterceptorResult {
  // False denies the operation before side effects for modify_operation and
  // validate. Post-commit denial is invalid.
  bool allowed = 1;
  // Human-readable reason for logs and denied gRPC status messages.
  string reason = 2;
  // Optional gRPC status code name for denials, e.g. "PERMISSION_DENIED".
  string status_code = 3;
  // RFC 6902 JSON patches. Only valid during modify_operation.
  repeated JsonPatch patches = 4;
  // Non-secret annotations included in gateway logs.
  map<string, string> log_annotations = 5;
}

message InterceptorManifest {
  // Human-readable interceptor name declared by the service.
  string name = 1;
  // Bindings declared by the interceptor service.
  repeated InterceptorBinding bindings = 2;
  // Optional default failure policy for bindings without their own policy.
  // Supported values are "fail_closed" and "fail_open".
  string failure_policy = 3;
  // True when this interceptor implements SnapshotProviderProfiles.
  bool provider_profiles = 4;
  // Exact JWT audience this service verifies on inbound OpenShell calls.
  // After authenticated Describe succeeds, the gateway refuses to start unless
  // this matches the operator-configured audience. A strict verifier may reject
  // an incorrect audience before returning this manifest. Empty skips this
  // post-authentication consistency check.
  string expected_audience = 5;
  // Gateway-interceptor protocol metadata. Required for negotiation.
  // Declare protocol 1.0 and list "openshell.gateway-interceptor.contract" in
  // supported_capabilities.
  openshell.extension.v1.PeerMetadata extension = 6;
}

message ProviderProfileSnapshot {
  // Opaque source revision used for cache freshness and sandbox reload checks.
  string revision = 1;
  // Complete profile snapshot vended by this source.
  repeated openshell.v1.ProviderProfile profiles = 2;
}

message InterceptorBinding {
  // Stable binding id used for config overrides and audit logs.
  string id = 1;
  // RPC selector. Selectors are intentionally tied to the public API shape.
  InterceptorSelector selector = 2;
  // Phases this binding wants to evaluate.
  repeated GatewayInterceptorPhase phases = 3;
  // Optional binding-specific failure policy.
  // Supported values are "fail_closed" and "fail_open".
  // Bindings that include post_commit must resolve to "fail_open" because the
  // gateway operation has already committed before that phase runs.
  string failure_policy = 4;
}

message InterceptorSelector {
  // Full selector form: "openshell.v1.OpenShell/CreateSandbox".
  string rpc = 1;
  // Structured service/method form. If rpc is set, it takes precedence.
  string service = 2;
  string method = 3;
}

message JsonPatch {
  string op = 1;
  string path = 2;
  google.protobuf.Value value = 3;
  string from = 4;
}