/*
 * Copyright 2014 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 com.amazonaws.services.dynamodbv2.testing;

import com.amazonaws.services.dynamodbv2.datamodeling.AttributeTransformer;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapperConfig;
import com.amazonaws.services.dynamodbv2.model.AttributeValue;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Collections;
import java.util.Map;

public class FakeParameters<T> {
  public static <T> AttributeTransformer.Parameters<T> getInstance(
      Class<T> clazz,
      Map<String, AttributeValue> attribs,
      DynamoDBMapperConfig config,
      String tableName,
      String hashKeyName,
      String rangeKeyName) {
    return getInstance(clazz, attribs, config, tableName, hashKeyName, rangeKeyName, false);
  }

  public static <T> AttributeTransformer.Parameters<T> getInstance(
      Class<T> clazz,
      Map<String, AttributeValue> attribs,
      DynamoDBMapperConfig config,
      String tableName,
      String hashKeyName,
      String rangeKeyName,
      boolean isPartialUpdate) {

    // We use this relatively insane proxy setup so that modifications to the Parameters
    // interface doesn't break our tests (unless it actually impacts our code).
    FakeParameters<T> fakeParams =
        new FakeParameters<T>(
            clazz, attribs, config, tableName, hashKeyName, rangeKeyName, isPartialUpdate);
    @SuppressWarnings("unchecked")
    AttributeTransformer.Parameters<T> proxyObject =
        (AttributeTransformer.Parameters<T>)
            Proxy.newProxyInstance(
                AttributeTransformer.class.getClassLoader(),
                new Class[] {AttributeTransformer.Parameters.class},
                new ParametersInvocationHandler<T>(fakeParams));
    return proxyObject;
  }

  private static class ParametersInvocationHandler<T> implements InvocationHandler {
    private final FakeParameters<T> params;

    public ParametersInvocationHandler(FakeParameters<T> params) {
      this.params = params;
    }

    @Override
    public Object invoke(Object obj, Method method, Object[] args) throws Throwable {
      if (args != null && args.length > 0) {
        throw new UnsupportedOperationException();
      }
      Method innerMethod = params.getClass().getMethod(method.getName());
      return innerMethod.invoke(params);
    }
  }

  private final Map<String, AttributeValue> attrs;
  private final Class<T> clazz;
  private final DynamoDBMapperConfig config;
  private final String tableName;
  private final String hashKeyName;
  private final String rangeKeyName;
  private final boolean isPartialUpdate;

  private FakeParameters(
      Class<T> clazz,
      Map<String, AttributeValue> attribs,
      DynamoDBMapperConfig config,
      String tableName,
      String hashKeyName,
      String rangeKeyName,
      boolean isPartialUpdate) {
    super();
    this.clazz = clazz;
    this.attrs = Collections.unmodifiableMap(attribs);
    this.config = config;
    this.tableName = tableName;
    this.hashKeyName = hashKeyName;
    this.rangeKeyName = rangeKeyName;
    this.isPartialUpdate = isPartialUpdate;
  }

  public Map<String, AttributeValue> getAttributeValues() {
    return attrs;
  }

  public Class<T> getModelClass() {
    return clazz;
  }

  public DynamoDBMapperConfig getMapperConfig() {
    return config;
  }

  public String getTableName() {
    return tableName;
  }

  public String getHashKeyName() {
    return hashKeyName;
  }

  public String getRangeKeyName() {
    return rangeKeyName;
  }

  public boolean isPartialUpdate() {
    return isPartialUpdate;
  }
}