// Copyright 2017 Google LLC. 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.

// Model an API surface for code generation.

syntax = "proto3";

package surface.v1;

// The Go package name.
option go_package = "./surface;surface_v1";

enum FieldKind {
  SCALAR = 0;
  MAP = 1;
  ARRAY = 2;
  REFERENCE = 3;
  ANY = 4;
}

enum TypeKind {
  STRUCT = 0; // implement with named fields
  OBJECT = 1; // implement with a map
}

enum Position {
  BODY = 0;
  HEADER = 1;
  FORMDATA = 2;
  QUERY = 3;
  PATH = 4;
}

// Field is a field in a definition and can be associated with
// a position in a request structure.
message Field {
  string name = 1;       // the name as specified in the API description
  string type = 2;       // the specified content type of the field
  FieldKind kind = 3;    // what kind of thing is this field? scalar, reference,
                         // array, map of strings to the specified type
  string format = 4;     // the specified format of the field
  Position position = 5; // "body", "header", "formdata", "query", or "path"

  string native_type = 6; // the programming-language native type of the field
  string field_name = 7;  // the name to use for a data structure field
  string parameter_name = 8; // the name to use for a function parameter

  bool serialize = 9; // true if this field should be serialized (to JSON, etc)

  repeated string enum_values =
      10; // enum values as specified in the API description
}

// Type typically corresponds to a definition, parameter, or response
// in an API and is represented by a type in generated code.
message Type {
  string name = 1;         // the name to use for the type
  TypeKind kind = 2;       // a meta-description of the type (struct, map, etc)
  string description = 3;  // a comment describing the type
  string content_type = 4; // if the type is a map, this is its content type
  repeated Field fields = 5; // the fields of the type

  string type_name = 6; // language-specific type name
}

// Method is an operation of an API and typically has associated client and
// server code.
message Method {
  string operation = 1;   // Operation ID
  string path = 2;        // HTTP path
  string method = 3;      // HTTP method name
  string description = 4; // description of method

  string name = 5; // Operation name, possibly generated from method and path
  string handler_name = 6; // name of the generated handler
  string processor_name =
      7; // name of the processing function in the service interface
  string client_name = 8; // name of client

  string parameters_type_name =
      9; // parameters (input), with fields corresponding to input parameters
  string responses_type_name = 10; // responses (output), with fields
                                   // corresponding to possible response values
}

// Model represents an API for code generation.
message Model {
  string name = 1;             // a free-form title for the API
  repeated Type types = 2;     // the types used by the API
  repeated Method methods = 3; // the methods (functions) of the API
  repeated string symbolic_references =
      4; // references to other OpenAPI files. Currently only supported for
         // OpenAPI v3.
}