firebase-ios-sdk/GeminiLanguageModel/Sources/GeminiAPIDataModels/GenerateContent/FunctionDeclaration.swift

// Copyright 2026 Google LLC
//
// 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.

import Foundation

/// An internal data model for `FunctionDeclaration`.
///
/// ### Gemini Developer API
///
/// Type: `GoogleAiGenerativelanguageV1betaFunctionDeclaration`
///
/// Structured representation of a function declaration as defined by the
/// [OpenAPI 3.03 specification](https://spec.openapis.org/oas/v3.0.3). Included
/// in this declaration are the function name and parameters. This
/// FunctionDeclaration is a representation of a block of code that can be used
/// as a `Tool` by the model and executed by the client.
///
/// ### Gemini Enterprise API
///
/// Type: `GoogleCloudAiplatformV1beta1FunctionDeclaration`
///
/// Structured representation of a function declaration as defined by the
/// [OpenAPI 3.0 specification](https://spec.openapis.org/oas/v3.0.3). Included
/// in this declaration are the function name, description, parameters and
/// response type. This FunctionDeclaration is a representation of a block of
/// code that can be used as a `Tool` by the model and executed by the client.
package struct FunctionDeclaration: Codable, Sendable, Equatable, Hashable {
  /// Required. The name of the function.
  ///
  /// ### Gemini Developer API
  ///
  /// Required. The name of the function.
  /// Must be a-z, A-Z, 0-9, or contain underscores, colons, dots, and dashes,
  /// with a maximum length of 128.
  ///
  /// ### Gemini Enterprise API
  ///
  /// Required. The name of the function to call.
  /// Must start with a letter or an underscore.
  /// Must be a-z, A-Z, 0-9, or contain underscores, dots, colons and dashes,
  /// with a maximum length of 128.
  package let name: String

  /// Required. A brief description of the function.
  ///
  /// ### Gemini Developer API
  ///
  /// Required. A brief description of the function.
  ///
  /// ### Gemini Enterprise API
  ///
  /// Optional. Description and purpose of the function.
  /// Model uses it to decide how and whether to call the function.
  package let description: String

  /// Optional. Describes the parameters to this function. Reflects the Open API 3.03
  ///
  /// ### Gemini Developer API
  ///
  /// Optional. Describes the parameters to this function. Reflects the Open API 3.03
  /// Parameter Object string Key: the name of the parameter. Parameter names are
  /// case sensitive. Schema Value: the Schema defining the type used for the
  /// parameter.
  ///
  /// ### Gemini Enterprise API
  ///
  /// Optional. Describes the parameters to this function in JSON Schema Object format.
  /// Reflects the Open API 3.03 Parameter Object. string Key: the name of the
  /// parameter. Parameter names are case sensitive. Schema Value: the Schema
  /// defining the type used for the parameter. For function with no parameters,
  /// this can be left unset.
  /// Parameter names must start with a letter or an underscore and must only
  /// contain chars a-z, A-Z, 0-9, or underscores with a maximum length of 64.
  /// Example with 1 required and 1 optional parameter:
  /// type: OBJECT
  /// properties:
  ///  param1:
  ///    type: STRING
  ///  param2:
  ///    type: INTEGER
  /// required:
  ///  - param1
  package let parameters: Schema?

  /// Optional. Describes the parameters to the function in JSON Schema format. The schema
  /// must describe an object where the properties are the parameters to the
  /// function. For example:
  ///
  /// ```
  /// {
  ///   "type": "object",
  ///   "properties": {
  ///     "name": { "type": "string" },
  ///     "age": { "type": "integer" }
  ///   },
  ///   "additionalProperties": false,
  ///   "required": ["name", "age"],
  ///   "propertyOrdering": ["name", "age"]
  /// }
  /// ```
  ///
  /// This field is mutually exclusive with `parameters`.
  package let parametersJsonSchema: JSONValue?

  /// Optional. Describes the output from this function in JSON Schema format. Reflects the
  /// Open API 3.03 Response Object. The Schema defines the type used for the
  /// response value of the function.
  package let response: Schema?

  /// Optional. Describes the output from this function in JSON Schema format. The value
  /// specified by the schema is the response value of the function.
  ///
  /// This field is mutually exclusive with `response`.
  package let responseJsonSchema: JSONValue?

  /// Optional. Specifies the function Behavior.
  ///
  /// ### Gemini Developer API
  ///
  /// Optional. Specifies the function Behavior.
  /// Currently only supported by the BidiGenerateContent method.
  ///
  /// ### Gemini Enterprise API
  ///
  /// Optional. Specifies the function Behavior.
  /// If not specified, the system keeps the current function call behavior.
  /// This field is currently only supported by the BidiGenerateContent method.
  package let behavior: Behavior?

  /// Creates a new `FunctionDeclaration`.
  ///
  /// - Parameters:
  ///   - name: Required. The name of the function. (behavior varies by backend). For more details, see ``name``.
  ///   - description: Required. A brief description of the function. (behavior varies by backend). For more details, see ``description``.
  ///   - parameters: Optional. Describes the parameters to this function. Reflects the Open API 3.03 (behavior varies by backend). For more details, see ``parameters``.
  ///   - parametersJsonSchema: Optional. Describes the parameters to the function in JSON Schema format. The schema
  ///   - response: Optional. Describes the output from this function in JSON Schema format. Reflects the
  ///   - responseJsonSchema: Optional. Describes the output from this function in JSON Schema format. The value
  ///   - behavior: Optional. Specifies the function Behavior. (behavior varies by backend). For more details, see ``behavior``.
  package init(
    name: String,
    description: String,
    parameters: Schema? = nil,
    parametersJsonSchema: JSONValue? = nil,
    response: Schema? = nil,
    responseJsonSchema: JSONValue? = nil,
    behavior: Behavior? = nil
  ) {
    self.name = name
    self.description = description
    self.parameters = parameters
    self.parametersJsonSchema = parametersJsonSchema
    self.response = response
    self.responseJsonSchema = responseJsonSchema
    self.behavior = behavior
  }
  enum CodingKeys: String, CodingKey {
    case name = "name"
    case description = "description"
    case parameters = "parameters"
    case parametersJsonSchema = "parametersJsonSchema"
    case response = "response"
    case responseJsonSchema = "responseJsonSchema"
    case behavior = "behavior"
  }
}