/*
 Copyright (c) 2009-2017, Haystack Software LLC https://www.arqbackup.com
 
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:
 
 * Redistributions of source code must retain the above copyright
 notice, this list of conditions and the following disclaimer.
 
 * Redistributions in binary form must reproduce the above copyright
 notice, this list of conditions and the following disclaimer in the
 documentation and/or other materials provided with the distribution.
 
 * Neither the names of PhotoMinds LLC or Haystack Software, nor the names of
 their contributors may be used to endorse or promote products derived from
 this software without specific prior written permission.
 
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */



#import "GlacierAuthorization.h"
#import "HTTPConnection.h"
#import "GlacierSigner.h"
#import "AWSRegion.h"
#import "ISO8601Date.h"
#import "SHA256Hash.h"
#import "NSString_extra.h"


@implementation GlacierAuthorization
- (id)initWithAWSRegion:(AWSRegion *)theAWSRegion connection:(id <HTTPConnection>)theConn requestBody:(NSData *)theRequestBody accessKey:(NSString *)theAccessKey signer:(id <GlacierSigner>)theSigner {
    if (self = [super init]) {
        awsRegion = [theAWSRegion retain];
        conn = [theConn retain];
        requestBody = [theRequestBody retain];
        accessKey = [theAccessKey retain];
        signer = [theSigner retain];
    }
    return self;
}
- (void)dealloc {
    [awsRegion release];
    [conn release];
    [requestBody release];
    [accessKey release];
    [signer release];
    [super dealloc];
}


#pragma mark NSObject
- (NSString *)description {
    NSMutableString *canonicalRequest = [[[NSMutableString alloc] init] autorelease];
    [canonicalRequest appendString:[conn requestMethod]];
    [canonicalRequest appendString:@"\n"];
    
    [canonicalRequest appendString:[conn requestPathInfo]];
    [canonicalRequest appendString:@"\n"];
    
    if ([conn requestQueryString] != nil) {
        NSString *query = [(NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
                                                                               (CFStringRef)[conn requestQueryString],
                                                                               (CFStringRef)@"=",
                                                                               (CFStringRef)@"!*'();:@&+$,/?%#[]",
                                                                               kCFStringEncodingUTF8) autorelease];
        
        [canonicalRequest appendString:query];
    }
    [canonicalRequest appendString:@"\n"];
    
    // Add sorted canonical headers:
    NSMutableArray *theHeaders = [NSMutableArray array];
    for (NSString *headerName in [conn requestHeaderKeys]) {
        NSString *lower = [headerName lowercaseString];
        [theHeaders addObject:[NSString stringWithFormat:@"%@:%@\n", lower, [conn requestHeaderForKey:headerName]]];
    }
    [theHeaders sortUsingSelector:@selector(compare:)];
    for (NSString *hdr in theHeaders) {
        [canonicalRequest appendString:hdr];
    }
    
    // Add a newline:
    [canonicalRequest appendString:@"\n"];
    
    NSMutableArray *theSortedLowercaseHeaderNames = [NSMutableArray array];
    for (NSString *headerName in [conn requestHeaderKeys]) {
        [theSortedLowercaseHeaderNames addObject:[headerName lowercaseString]];
    }
    [theSortedLowercaseHeaderNames sortUsingSelector:@selector(compare:)];
    
    // Create list of names of the signed headers:
    NSMutableString *namesOfSignedHeaders = [NSMutableString string];
    NSString *separator = @"";
    for (NSString *name in theSortedLowercaseHeaderNames) {
        [namesOfSignedHeaders appendString:separator];
        separator = @";";
        [namesOfSignedHeaders appendString:name];
    }
    
    // Add list of signed headers (header names):
    [canonicalRequest appendString:namesOfSignedHeaders];
    [canonicalRequest appendString:@"\n"];
    
    // Add hash of payload:
    NSData *payload = requestBody;
    if (payload == nil) {
        payload = [NSData data];
    }
    [canonicalRequest appendString:[NSString hexStringWithData:[SHA256Hash hashData:payload]]];


    NSString *dateStamp = [[ISO8601Date sharedISO8601Date] basicDateStringFromDate:[conn date]];
    NSString *dateTime = [[ISO8601Date sharedISO8601Date] basicDateTimeStringFromDate:[conn date]];
    
    NSString *scope = [NSString stringWithFormat:@"%@/%@/glacier/aws4_request", dateStamp, [awsRegion regionName]];
    NSString *signingCredentials = [NSString stringWithFormat:@"%@/%@", accessKey, scope];
    
    NSData *canonicalRequestData = [canonicalRequest dataUsingEncoding:NSUTF8StringEncoding];
    NSString *canonicalRequestHashHex = [NSString hexStringWithData:[SHA256Hash hashData:canonicalRequestData]];
    
    NSString *stringToSign = [NSString stringWithFormat:@"AWS4-HMAC-SHA256\n%@\n%@\n%@", dateTime, scope, canonicalRequestHashHex];
    
    //FIXME: Extract the service name from the hostname (see AwsHostNameUtils.parseServiceName() method in Java AWS SDK).
    NSString *signature = [signer signString:stringToSign withDateStamp:dateStamp regionName:[awsRegion regionName] serviceName:@"glacier"];
    
    NSString *ret = [[[NSString alloc] initWithFormat:@"AWS4-HMAC-SHA256 Credential=%@, SignedHeaders=%@, Signature=%@", signingCredentials, namesOfSignedHeaders, signature] autorelease];
    return ret;
}
@end