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/*
 * Copyright 2017-2020 original 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
 *
 * https://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 io.micronaut.http.client.annotation;

import io.micronaut.aop.Introduction;
import io.micronaut.context.annotation.AliasFor;
import io.micronaut.core.annotation.Experimental;
import io.micronaut.core.annotation.NonNull;
import io.micronaut.http.HttpVersion;
import io.micronaut.http.annotation.Consumes;
import io.micronaut.http.annotation.Produces;
import io.micronaut.http.client.HttpClientConfiguration;
import io.micronaut.http.client.HttpVersionSelection;
import io.micronaut.http.hateoas.JsonError;
import jakarta.inject.Singleton;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;

import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Allows defining declarative HTTP clients and customizing injection for injecting {@link io.micronaut.http.client.HttpClient} implementations.
 *
 * @author Graeme Rocher
 * @since 1.0
 */
@Documented
@Retention(RUNTIME)
@Introduction
@Singleton
// tag::value[]
public @interface Client {

    /**
     * @return The URL or service ID of the remote service
     */
    @AliasFor(member = "id") // <1>
    String value() default "";

    /**
     * @return The ID of the client
     */
    @AliasFor(member = "value") // <2>
    String id() default "";
// end::value[]

    /**
     * The interface definition type. When set to {@link DefinitionType.SERVER} the {@link Produces} and {@link Consumes}
     * definition evaluated for each method of the interface will be reversed .
     *
     * Whilst not necessarily recommended, there are scenarios like testing where it is useful to share a common interface between client and server and use the
     * interface to create a new client declarative client. The client typically needs to produce the content type accepted by the server and consume the content type
     * produced by the server. In this arrangement using the interface directly will not result in the correct behaviour.
     *
     * In this scenario you can set {@link DefinitionType} to {@link DefinitionType.SERVER} which will ensure the requests sent by the client use the content type declared by the {@link Consumes}
     *  annotation of the interface and that responses use the content type declared by the {@link Produces}.
     *
     * The default behaviour is to use {@link DefinitionType.CLIENT} where the inverse of the above is true.
     *
     * @return The interface definition type
     * @since 4.8.0
     * @see Consumes
     * @see Produces
     */
    @Experimental
    @NonNull
    DefinitionType definitionType() default DefinitionType.CLIENT;

    /**
     * The base URI for the client. Only to be used in
     * conjunction with {@link #id()}.
     *
     * @return The base URI
     */
    String path() default "";

    /**
     * @return The type used to decode errors
     */
    Class errorType() default JsonError.class;

    /**
     * @return The http client configuration bean to use
     */
    Class configuration() default HttpClientConfiguration.class;

    /**
     * The HTTP version.
     *
     * @return The HTTP version of the client.
     * @deprecated There are now separate settings for HTTP and HTTPS connections. To configure
     * HTTP connections (e.g. for h2c), use {@link #plaintextMode}. To configure ALPN, set
     * {@link #alpnModes}.
     */
    @Deprecated
    HttpVersion httpVersion() default HttpVersion.HTTP_1_1;

    /**
     * The connection mode to use for plaintext (http as opposed to https) connections.
     * 

     * Note: If {@link #httpVersion} is set, this setting is ignored!
     *
     * @return The plaintext connection mode.
     * @since 4.0.0
     */
    @NonNull
    HttpVersionSelection.PlaintextMode plaintextMode() default HttpVersionSelection.PlaintextMode.HTTP_1;

    /**
     * The protocols to support for TLS ALPN. If HTTP 2 is included, this will also restrict the
     * TLS cipher suites to those supported by the HTTP 2 standard.
     * 

     * Note: If {@link #httpVersion} is set, this setting is ignored!
     *
     * @return The supported ALPN protocols.
     * @since 4.0.0
     */
    @NonNull
    String[] alpnModes() default {
        HttpVersionSelection.ALPN_HTTP_2,
        HttpVersionSelection.ALPN_HTTP_1
    };

    /**
     * The interface definition type.
     *
     * @since 4.8.0
     */
    @Experimental
    enum DefinitionType {
        /**
         * Client interface definition type.
         */
        CLIENT,
        /**
         * Server (controller) interface definition type.
         */
        SERVER;

        /**
         * Returns true, if this definition type is {@link DefinitionType.CLIENT}.
         *
         * @return true, if this definition type is {@link DefinitionType.CLIENT}.
         */
        public boolean isClient() {
            return this == CLIENT;
        }

        /**
         * Returns true, if this definition type is {@link DefinitionType.SERVER}.
         *
         * @return true, if this definition type is {@link DefinitionType.SERVER}.
         */
        public boolean isServer() {
            return this == SERVER;
        }
    }
}