/*
 * Copyright 2010-2016 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.s3.internal;

import com.amazonaws.AmazonClientException;
import com.amazonaws.Request;
import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.AWSSessionCredentials;
import com.amazonaws.auth.AbstractAWSSigner;
import com.amazonaws.auth.SigningAlgorithm;

import java.util.Date;

public class S3QueryStringSigner extends AbstractAWSSigner {

    /**
     * The HTTP verb (GET, PUT, HEAD, DELETE) the request to sign is using.
     * TODO: We need to know the HTTP verb in order to create the authentication
     * signature, but we don't have easy access to it through the request
     * object. Maybe it'd be better for the S3 signer (or all signers?) to work
     * directly off of the HttpRequest instead of the Request object?
     */
    private final String httpVerb;

    /**
     * The canonical resource path portion of the S3 string to sign. Examples:
     * "/", "/<bucket name>/", or "/<bucket name>/<key>" TODO: We don't want to
     * hold the resource path as member data in the S3 signer, but we need
     * access to it and can't get it through the request yet.
     */
    private final String resourcePath;

    private final Date expiration;

    public S3QueryStringSigner(String httpVerb, String resourcePath, Date expiration) {
        this.httpVerb = httpVerb;
        this.resourcePath = resourcePath;
        this.expiration = expiration;

        if (resourcePath == null)
            throw new IllegalArgumentException("Parameter resourcePath is empty");
    }

    @Override
    public void sign(Request<?> request, AWSCredentials credentials) throws AmazonClientException {
        AWSCredentials sanitizedCredentials = sanitizeCredentials(credentials);

        if (sanitizedCredentials instanceof AWSSessionCredentials) {
            addSessionCredentials(request, (AWSSessionCredentials) sanitizedCredentials);
        }

        String expirationInSeconds = Long.toString(expiration.getTime() / 1000L);

        String canonicalString = RestUtils.makeS3CanonicalString(
                httpVerb, resourcePath, request, expirationInSeconds);

        String signature = super.signAndBase64Encode(canonicalString,
                sanitizedCredentials.getAWSSecretKey(), SigningAlgorithm.HmacSHA1);

        request.addParameter("AWSAccessKeyId", sanitizedCredentials.getAWSAccessKeyId());
        request.addParameter("Expires", expirationInSeconds);
        request.addParameter("Signature", signature);
    }

    @Override
    protected void addSessionCredentials(Request<?> request, AWSSessionCredentials credentials) {
        request.addParameter("x-amz-security-token", credentials.getSessionToken());
    }
}