import { JSONSchema } from '@genkit-ai/core';
import { GenerateResponseChunk } from '../generate/chunk.js';
import { Message } from '../message.js';
import { ModelRequest } from '../model-types.js';
import '../parts.js';

/**
 * Copyright 2024 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.
 */

type OutputContentTypes = 'application/json' | 'text/plain';
interface Formatter<O = unknown, CO = unknown> {
    name: string;
    config: ModelRequest['output'] & {
        defaultInstructions?: false;
    };
    handler: (schema?: JSONSchema) => {
        parseMessage(message: Message): O;
        parseChunk?: (chunk: GenerateResponseChunk) => CO;
        instructions?: string;
    };
}

export type { Formatter, OutputContentTypes };