/*
 * Copyright (C) 2012 Square, Inc.
 * Copyright (C) 2007 The Guava Authors
 *
 * 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.
 */
package retrofit;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.concurrent.Executor;

import retrofit.client.Request;
import retrofit.client.Response;
import retrofit.mime.TypedByteArray;
import retrofit.mime.TypedInput;
import retrofit.mime.TypedOutput;

final class Utils {
    private static final int BUFFER_SIZE = 0x1000;

    private Utils() {
        // No instances.
    }

    /**
     * Creates a {@code byte[]} from reading the entirety of an {@link InputStream}. May return an
     * empty array but never {@code null}.
     * <p/>
     * Copied from Guava's {@code ByteStreams} class.
     */
    static byte[] streamToBytes(InputStream stream) throws IOException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        if (stream != null) {
            byte[] buf = new byte[BUFFER_SIZE];
            int r;
            while ((r = stream.read(buf)) != -1) {
                baos.write(buf, 0, r);
            }
        }
        return baos.toByteArray();
    }

    /**
     * Conditionally replace a {@link Request} with an identical copy whose body is backed by a
     * byte[] rather than an input stream.
     */
    static Request readBodyToBytesIfNecessary(Request request) throws IOException {
        TypedOutput body = request.getBody();
        if (body == null || body instanceof TypedByteArray) {
            return request;
        }

        String bodyMime = body.mimeType();
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        body.writeTo(baos);
        body = new TypedByteArray(bodyMime, baos.toByteArray());

        return new Request(request.getMethod(), request.getUrl(), request.getHeaders(), body);
    }

    /**
     * Conditionally replace a {@link Response} with an identical copy whose body is backed by a
     * byte[] rather than an input stream.
     */
    static Response readBodyToBytesIfNecessary(Response response) throws IOException {
        TypedInput body = response.getBody();
        if (body == null || body instanceof TypedByteArray) {
            return response;
        }

        String bodyMime = body.mimeType();
        byte[] bodyBytes = Utils.streamToBytes(body.in());
        body = new TypedByteArray(bodyMime, bodyBytes);

        return replaceResponseBody(response, body);
    }

    static Response replaceResponseBody(Response response, TypedInput body) {
        return new Response(response.getStatus(), response.getReason(), response.getHeaders(), body);
    }

    static class SynchronousExecutor implements Executor {
        @Override
        public void execute(Runnable runnable) {
            runnable.run();
        }
    }
}