/*
 * Copyright 2015 the original author or 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
 *
 *      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.springframework.social.connect;

import java.io.Serializable;

/**
 * The unique business key for a {@link Connection} instance.
 * A composite key that consists of the providerId (e.g. "facebook") plus providerUserId (e.g. "125660").
 * Provides the basis for connection equals() and hashCode().
 * @author Keith Donald
 */
@SuppressWarnings("serial")
public final class ConnectionKey implements Serializable {
	
	private final String providerId;
	
	private final String providerUserId;

	/**
	 * Creates a new {@link ConnectionKey}.
	 * @param providerId the id of the provider e.g. facebook
	 * @param providerUserId id of the provider user account e.g. '125660'
	 */
	public ConnectionKey(String providerId, String providerUserId) {
		this.providerId = providerId;
		this.providerUserId = providerUserId;
	}
	
	/**
	 * The id of the provider as it is registered in the system.
	 * This value should never change.
	 * Never null.
	 * @return The id of the provider as it is registered in the system.
	 */	
	public String getProviderId() {
		return providerId;
	}

	/**
	 * The id of the external provider user representing the remote end of the connection.
	 * May be null if this information is not exposed by the provider.
	 * This value should never change.
	 * Must be present to support sign-in by the provider user.
	 * Must be present to establish multiple connections with the provider.
	 * @return The id of the external provider user representing the remote end of the connection.
	 */
	public String getProviderUserId() {
		return providerUserId;
	}
	
	// object identity
	
	public boolean equals(Object o) {
		if (!(o instanceof ConnectionKey)) {
			return false;
		}
		ConnectionKey other = (ConnectionKey) o;
		boolean sameProvider = providerId.equals(other.providerId);
		return providerUserId != null ? sameProvider && providerUserId.equals(other.providerUserId) : sameProvider && other.providerUserId == null;
	}
	
	public int hashCode() {
		int hashCode = providerId.hashCode();
		return providerUserId != null ? hashCode + providerUserId.hashCode() : hashCode;
	}
	
	public String toString() {
		return providerId + ":" + providerUserId;
	}

}