/*
 * Copyright Amazon.com, Inc. or its affiliates. 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.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. This file 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 software.amazon.awssdk.http;

import static java.util.Collections.singletonList;

import java.io.InputStream;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import software.amazon.awssdk.annotations.Immutable;
import software.amazon.awssdk.annotations.SdkProtectedApi;

/**
 * An immutable HTTP response with a possible HTTP body.
 *
 * <p>All implementations of this interface MUST be immutable. Instead of implementing this interface, consider using
 * {@link #builder()} to create an instance.</p>
 */
@SdkProtectedApi
@Immutable
public interface SdkHttpFullResponse
        extends SdkHttpResponse {
    /**
     * @return Builder instance to construct a {@link DefaultSdkHttpFullResponse}.
     */
    static Builder builder() {
        return new DefaultSdkHttpFullResponse.Builder();
    }

    @Override
    Builder toBuilder();

    /**
     * Returns the optional stream containing the payload data returned by the service. Note: an {@link AbortableInputStream}
     * is returned instead of an {@link InputStream}. This allows the stream to be aborted before all content is read, which
     * usually means destroying the underlying HTTP connection. This may be implemented differently in other HTTP implementations.
     *
     * <p>When the response does not include payload data, this will return {@link Optional#empty()}.</p>
     *
     * @return The optional stream containing the payload data included in this response, or empty if there is no payload.
     */
    Optional<AbortableInputStream> content();

    /**
     * Builder for a {@link DefaultSdkHttpFullResponse}.
     */
    interface Builder extends SdkHttpResponse.Builder {
        /**
         * The status text, exactly as it was configured with {@link #statusText(String)}.
         */
        @Override
        String statusText();

        /**
         * Configure an {@link SdkHttpResponse#statusText()} to be used in the created HTTP response. This is not validated
         * until the http response is created.
         */
        @Override
        Builder statusText(String statusText);

        /**
         * The status text, exactly as it was configured with {@link #statusCode(int)}.
         */
        @Override
        int statusCode();

        /**
         * Configure an {@link SdkHttpResponse#statusCode()} to be used in the created HTTP response. This is not validated
         * until the http response is created.
         */
        @Override
        Builder statusCode(int statusCode);

        /**
         * The query parameters, exactly as they were configured with {@link #headers(Map)},
         * {@link #putHeader(String, String)} and {@link #putHeader(String, List)}.
         */
        @Override
        Map<String, List<String>> headers();

        /**
         * Add a single header to be included in the created HTTP response.
         *
         * <p>This completely <b>OVERRIDES</b> any values already configured with this header name in the builder.</p>
         *
         * @param headerName The name of the header to add (eg. "Host")
         * @param headerValue The value for the header
         */
        @Override
        default Builder putHeader(String headerName, String headerValue) {
            return putHeader(headerName, singletonList(headerValue));
        }

        /**
         * Add a single header with multiple values to be included in the created HTTP response.
         *
         * <p>This completely <b>OVERRIDES</b> any values already configured with this header name in the builder.</p>
         *
         * @param headerName The name of the header to add
         * @param headerValues The values for the header
         */
        @Override
        Builder putHeader(String headerName, List<String> headerValues);


        /**
         * Add a single header to be included in the created HTTP request.
         *
         * <p>This will <b>ADD</b> the value to any existing values already configured with this header name in
         * the builder.</p>
         *
         * @param headerName The name of the header to add
         * @param headerValue The value for the header
         */
        @Override
        Builder appendHeader(String headerName, String headerValue);

        /**
         * Configure an {@link SdkHttpResponse#headers()} to be used in the created HTTP response. This is not validated
         * until the http response is created. This overrides any values currently configured in the builder.
         */
        @Override
        Builder headers(Map<String, List<String>> headers);

        /**
         * Remove all values for the requested header from this builder.
         */
        @Override
        Builder removeHeader(String headerName);

        /**
         * Removes all headers from this builder.
         */
        @Override
        Builder clearHeaders();

        /**
         * The content, exactly as it was configured with {@link #content(AbortableInputStream)}.
         */
        AbortableInputStream content();

        /**
         * Configure an {@link SdkHttpFullResponse#content()} to be used in the HTTP response. This is not validated until
         * the http response is created.
         *
         * <p>Implementers should implement the abort method on the input stream to drop all remaining content with the service.
         * This is usually done by closing the service connection.</p>
         */
        Builder content(AbortableInputStream content);

        @Override
        SdkHttpFullResponse build();
    }
}