/**
    *
    * Copyright (C) 2011 Cloud Conscious, LLC. <info@cloudconscious.com>
    *
    * ====================================================================
    * 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 org.jclouds.aws.util;
  
  import static com.google.common.base.Preconditions.checkArgument;
  import static com.google.common.base.Preconditions.checkNotNull;
  import static org.jclouds.aws.reference.AWSConstants.PROPERTY_HEADER_TAG;
  
  import javax.annotation.Resource;
  import javax.inject.Inject;
  import javax.inject.Named;
  import javax.inject.Provider;
  import javax.inject.Singleton;
  
  import org.jclouds.aws.domain.AWSError;
  import org.jclouds.aws.domain.Region;
  import org.jclouds.aws.xml.ErrorHandler;
  import org.jclouds.domain.Location;
  import org.jclouds.domain.LocationScope;
  import org.jclouds.http.HttpRequest;
  import org.jclouds.http.HttpResponse;
  import org.jclouds.http.functions.ParseSax;
  import org.jclouds.http.functions.ParseSax.Factory;
  import org.jclouds.http.utils.ModifyRequest;
  import org.jclouds.logging.Logger;
  import org.jclouds.rest.RequestSigner;
  import org.jclouds.rest.internal.GeneratedHttpRequest;
  
  import com.google.common.base.Function;
  import com.google.common.collect.ImmutableMultimap;
  import com.google.common.collect.ImmutableMultimap.Builder;
  
  /**
   * Needed to sign and verify requests and responses.
   * 
   * @author Adrian Cole
   */
  @Singleton
  public class AWSUtils {
     @Singleton
     public static class GetRegionFromLocation implements Function<Location, String> {
        public String apply(Location location) {
           String region = location.getScope() == LocationScope.REGION ? location.getId() : location.getParent().getId();
           return region;
        }
     }
  
     private final RequestSigner signer;
     private final ParseSax.Factory factory;
     private final Provider<ErrorHandler> errorHandlerProvider;
     private final String requestId;
     private final String requestToken;
     @Resource
     protected Logger logger = Logger.NULL;
  
     @Inject
     AWSUtils(@Named(PROPERTY_HEADER_TAG) String headerTag, RequestSigner signer, Factory factory,
           Provider<ErrorHandler> errorHandlerProvider) {
        this.signer = signer;
        this.factory = factory;
        this.errorHandlerProvider = errorHandlerProvider;
        this.requestId = String.format("x-%s-request-id", headerTag);
        this.requestToken = String.format("x-%s-id-2", headerTag);
     }
  
     public AWSError parseAWSErrorFromContent(HttpRequest request, HttpResponse response) {
        // HEAD has no content
        if (response.getPayload() == null)
           return null;
        // Eucalyptus and Walrus occasionally return text/plain
        if (response.getPayload().getContentMetadata().getContentType() != null
              && response.getPayload().getContentMetadata().getContentType().indexOf("text/plain") != -1)
           return null;
        try {
           AWSError error = (AWSError) factory.create(errorHandlerProvider.get()).setContext(request).apply(response);
           if (error.getRequestId() == null)
              error.setRequestId(response.getFirstHeaderOrNull(requestId));
           error.setRequestToken(response.getFirstHeaderOrNull(requestToken));
           if ("SignatureDoesNotMatch".equals(error.getCode())) {
              error.setStringSigned(signer.createStringToSign(request));
              error.setSignature(signer.sign(error.getStringSigned()));
           }
           return error;
       } catch (RuntimeException e) {
          logger.warn(e, "error parsing error");
          return null;
       }
    }
 
    public static <R extends HttpRequest> R indexStringArrayToFormValuesWithStringFormat(R request, String format,
          Object input) {
       checkArgument(checkNotNull(input, "input") instanceof String[], "this binder is only valid for String[] : "
             + input.getClass());
       String[] values = (String[]) input;
       Builder<String, String> builder = ImmutableMultimap.<String, String> builder();
       for (int i = 0; i < values.length; i++) {
          builder.put(String.format(format, (i + 1)), checkNotNull(values[i], format.toLowerCase() + "s[" + i + "]"));
       }
       ImmutableMultimap<String, String> forms = builder.build();
       return forms.size() == 0 ? request : ModifyRequest.putFormParams(request, forms);
    }
 
    // TODO: make this more dynamic
    public static boolean isRegion(String regionName) {
       return Region.DEFAULT_REGIONS.contains(regionName);
    }
 
    public static <R extends HttpRequest> R indexIterableToFormValuesWithPrefix(R request, String prefix, Object input) {
       checkArgument(checkNotNull(input, "input") instanceof Iterable<?>, "this binder is only valid for Iterable<?>: "
             + input.getClass());
       Iterable<?> values = (Iterable<?>) input;
       Builder<String, String> builder = ImmutableMultimap.<String, String> builder();
       int i = 0;
       for (Object o : values) {
          builder.put(prefix + "." + (i++ + 1), checkNotNull(o.toString(), prefix.toLowerCase() + "s[" + i + "]"));
       }
       ImmutableMultimap<String, String> forms = builder.build();
       return forms.size() == 0 ? request : ModifyRequest.putFormParams(request, forms);
    }
 
    public static <R extends HttpRequest> R indexStringArrayToFormValuesWithPrefix(R request, String prefix, Object input) {
       checkArgument(checkNotNull(input, "input") instanceof String[], "this binder is only valid for String[] : "
             + input.getClass());
       String[] values = (String[]) input;
       Builder<String, String> builder = ImmutableMultimap.<String, String> builder();
       for (int i = 0; i < values.length; i++) {
          builder.put(prefix + "." + (i + 1), checkNotNull(values[i], prefix.toLowerCase() + "s[" + i + "]"));
       }
       ImmutableMultimap<String, String> forms = builder.build();
       return forms.size() == 0 ? request : ModifyRequest.putFormParams(request, forms);
    }
 
    public static String getRegionFromLocationOrNull(Location location) {
       return location.getScope() == LocationScope.ZONE ? location.getParent().getId() : location.getId();
    }
 
    // there may not be a region, and in this case we do-not encode it into the string
    public static String[] parseHandle(String id) {
       String[] parts = checkNotNull(id, "id").split("/");
       return (parts.length == 1) ? new String[] { null, id } : parts;
    }
 
    public static String findRegionInArgsOrNull(GeneratedHttpRequest<?> gRequest) {
       for (Object arg : gRequest.getArgs()) {
          if (arg instanceof String) {
             String regionName = (String) arg;
             // TODO regions may not be amazon regions!
             // take from a configured value
             if (isRegion(regionName))
                return regionName;
          }
       }
       return null;
    }
 }