/*
 * Copyright 2013 Netflix, Inc.
 *
 * 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 feign;

import javax.inject.Named;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.net.URI;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import static feign.Util.checkState;
import static feign.Util.emptyToNull;

/**
 * Defines what annotations and values are valid on interfaces.
 */
public interface Contract {

  /**
   * Called to parse the methods in the class that are linked to HTTP requests.
   */
  List<MethodMetadata> parseAndValidatateMetadata(Class<?> declaring);

  public static abstract class BaseContract implements Contract {

    @Override public List<MethodMetadata> parseAndValidatateMetadata(Class<?> declaring) {
      List<MethodMetadata> metadata = new ArrayList<MethodMetadata>();
      for (Method method : declaring.getDeclaredMethods()) {
        if (method.getDeclaringClass() == Object.class)
          continue;
        metadata.add(parseAndValidatateMetadata(method));
      }
      return metadata;
    }

    /**
     * Called indirectly by {@link #parseAndValidatateMetadata(Class)}.
     */
    public MethodMetadata parseAndValidatateMetadata(Method method) {
      MethodMetadata data = new MethodMetadata();
      data.returnType(method.getGenericReturnType());
      data.configKey(Feign.configKey(method));

      for (Annotation methodAnnotation : method.getAnnotations()) {
        processAnnotationOnMethod(data, methodAnnotation, method);
      }
      checkState(data.template().method() != null, "Method %s not annotated with HTTP method type (ex. GET, POST)",
          me