/* Implementation for GSHTTPAuthentication for GNUstep
   Copyright (C) 2006 Software Foundation, Inc.

   Written by:  Richard Frith-Macdonald <rfm@gnu.org>
   Date: 2006
   
   This file is part of the GNUstep Base Library.

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.
   
   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.
   
   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, write to the Free
   Software Foundation, Inc., 31 Milk Street #960789 Boston, MA 02196 USA.
   */ 

#import "common.h"
#import "GSURLPrivate.h"
#import "Foundation/NSDictionary.h"
#import "Foundation/NSEnumerator.h"
#import "Foundation/NSScanner.h"
#import "Foundation/NSSet.h"
#import "Foundation/NSValue.h"
#import "GNUstepBase/GSMime.h"
#import "GNUstepBase/NSData+GNUstepBase.h"


static NSMutableDictionary	*domainMap = nil;
static NSMutableSet		*spaces = nil;
static NSMutableDictionary	*store = nil;
static NSLock		*storeLock = nil;
static GSMimeParser		*mimeParser = nil;

@interface NSData(GSHTTPDigest)
- (NSString*) digestHex;
@end
@implementation NSData(GSHTTPDigest)
- (NSString*) digestHex
{
  static const char	*hexChars = "0123456789abcdef";
  unsigned		slen = [self length];
  unsigned		dlen = slen * 2;
  const unsigned char	*src = (const unsigned char *)[self bytes];
  char			*dst;
  unsigned		spos = 0;
  unsigned		dpos = 0;
  NSData		*data;
  NSString		*string;

  dst = (char*)NSZoneMalloc(NSDefaultMallocZone(), dlen);
  while (spos < slen)
    {
      unsigned char	c = src[spos++];

      dst[dpos++] = hexChars[(c >> 4) & 0x0f];
      dst[dpos++] = hexChars[c & 0x0f];
    }
  data = [NSData allocWithZone: NSDefaultMallocZone()];
  data = [data initWithBytesNoCopy: dst length: dlen];
  string = [[NSString alloc] initWithData: data
				 encoding: NSASCIIStringEncoding];
  RELEASE(data);
  return AUTORELEASE(string);
}
@end



@implementation GSHTTPAuthentication

+ (void) initialize
{
  if (store == nil)
    {
      mimeParser = [GSMimeParser new];
      [[NSObject leakAt: &mimeParser] release];
      spaces = [NSMutableSet new];
      [[NSObject leakAt: &spaces] release];
      domainMap = [NSMutableDictionary new];
      [[NSObject leakAt: &domainMap] release];
      store = [NSMutableDictionary new];
      [[NSObject leakAt: &store] release];
      storeLock = [NSLock new];
      [[NSObject leakAt: &storeLock] release];
    }
}

+ (GSHTTPAuthentication *) authenticationWithCredential:
  (NSURLCredential*)credential
  inProtectionSpace: (NSURLProtectionSpace*)space
{
  NSMutableDictionary	*cDict = nil;
  NSURLProtectionSpace	*known = nil;
  GSHTTPAuthentication	*authentication = nil;

  NSAssert([credential isKindOfClass: [NSURLCredential class]] == YES,
    NSInvalidArgumentException);
  NSAssert([space isKindOfClass: [NSURLProtectionSpace class]] == YES,
    NSInvalidArgumentException);

  [storeLock lock];
  NS_DURING
    {
      /*
       * Keep track of known protection spaces so we don't make lots of
       * duplicate copies, but share one copy between authentication objects.
       */
      known = [spaces member: space];
      if (known == nil)
	{
	  [spaces addObject: space];
	  known = [spaces member: space];
	}
      space = known;
      cDict = [store objectForKey: space];
      if (cDict == nil)
	{
	  cDict = [NSMutableDictionary new];
	  [store setObject: cDict forKey: space];
	  RELEASE(cDict);
	}
      authentication = [cDict objectForKey: credential];

      if (authentication == nil)
	{
	  authentication = [[GSHTTPAuthentication alloc]
	    initWithCredential: credential
	     inProtectionSpace: space];
	  if (authentication != nil)
	    {
	      [cDict setObject: authentication
			forKey: [authentication credential]];
	      RELEASE(authentication);
	    }
	}
      IF_NO_ARC([[authentication retain] autorelease];)
    }
  NS_HANDLER
    {
      [storeLock unlock];
      [localException raise];
    }
  NS_ENDHANDLER
  [storeLock unlock];
  return authentication;
}

+ (NSURLProtectionSpace*) protectionSpaceForAuthentication: (NSString*)auth
                                                requestURL: (NSURL*)URL;
{
  if ([auth isKindOfClass: [NSString class]] == YES)
    {
      NSString			*method = nil;
      NSURLProtectionSpace	*space;
      NSScanner			*sc;
      NSString			*domain = nil;
      NSString			*realm = nil;
      NSString			*key;
      NSString			*val;

      space = [self protectionSpaceForURL: URL];
      sc = [NSScanner scannerWithString: auth];
      key = [mimeParser scanName: sc];
      if ([key caseInsensitiveCompare: @"Basic"] == NSOrderedSame)
        {
	  method = NSURLAuthenticationMethodHTTPBasic;
	  domain = [URL path];
	}
      else if ([key caseInsensitiveCompare: @"Digest"] == NSOrderedSame)
        {
	  method = NSURLAuthenticationMethodHTTPDigest;
	}
      else if ([key caseInsensitiveCompare: @"NTLM"] == NSOrderedSame)
        {
	  method = NSURLAuthenticationMethodNTLM;
	}
      else if ([key caseInsensitiveCompare: @"Negotiate"] == NSOrderedSame)
        {
	  method = NSURLAuthenticationMethodNegotiate;
	}
      else
	{
	  return nil;	// Unknown authentication
	}
      while ((key = [mimeParser scanName: sc]) != nil)
	{
	  if ([sc scanString: @"=" intoString: 0] == NO)
	    {
	      return nil;	// Bad name=value specification
	    }
	  if ((val = [mimeParser scanToken: sc]) == nil)
	    {
	      return nil;	// Bad name=value specification
	    }
	  if ([key caseInsensitiveCompare: @"domain"] == NSOrderedSame)
	    {
	      domain = val;
	    }
	  else if ([key caseInsensitiveCompare: @"realm"] == NSOrderedSame)
	    {
	      realm = val;
	    }
	  if ([sc scanString: @"," intoString: 0] == NO)
	    {
	      break;	// No more in list.
	    }
	}
      if (realm == nil)
        {
	  return nil;		// No realm to authenticate in
	}

      /*
       * If the realm and authentication method match the space we
       * found for the URL, assume that it is unchanged.
       */
      if ([[space realm] isEqualToString: realm]
	&& [space authenticationMethod] == method)
	{
	  return space;
	}

      space = [[NSURLProtectionSpace alloc] initWithHost: [URL host]
						    port: [[URL port] intValue]
						protocol: [URL scheme]
						   realm: realm
				    authenticationMethod: method];
      [self setProtectionSpace: space
		    forDomains: [domain componentsSeparatedByString: @" "]
		       baseURL: URL];
      return AUTORELEASE(space);
    }
  return nil;
}

+ (NSURLProtectionSpace *) protectionSpaceForURL: (NSURL*)URL
{
  NSURLProtectionSpace	*space = nil;
  NSString		*scheme;
  NSNumber		*port;
  NSString		*server;

  scheme = [URL scheme];
  port = [URL port];
  if ([port intValue] == 80 && [scheme isEqualToString: @"http"])
    {
      port = nil;
    }
  else if ([port intValue] == 443 && [scheme isEqualToString: @"https"])
    {
      port = nil;
    }
  if ([port intValue] == 0)
    {
      server = [NSString stringWithFormat: @"%@://%@",
	scheme, [URL host]];
    }
  else
    {
      server = [NSString stringWithFormat: @"%@://%@:%@",
	scheme, [URL host], port];
    }

  [storeLock lock];
  NS_DURING
    {
      NSString		*found = nil;
      NSDictionary	*sDict;
      NSArray		*keys;
      unsigned		count;
      NSString		*path;

      sDict = [domainMap objectForKey: server];
      keys = [sDict allKeys];
      count = [keys count];
      path = [URL path];
      while (count-- > 0)
	{
	  NSString	*key = [keys objectAtIndex: count];
	  unsigned	kl = [key length];

	  if (found == nil || kl > [found length])
	    {
	      if (kl == 0 || [path hasPrefix: key] == YES)
		{
		  found = key;
		}
	    }
	}
      if (found != nil)
	{
	  space = AUTORELEASE(RETAIN([sDict objectForKey: found]));
	}
    }
  NS_HANDLER
    {
      [storeLock unlock];
      [localException raise];
    }
  NS_ENDHANDLER
  [storeLock unlock];
  return space;
}

+ (void) setProtectionSpace: (NSURLProtectionSpace *)space
		 forDomains: (NSArray*)domains
		    baseURL: (NSURL*)base
{
  /*
   * If there are no URIs specified, everything on the
   * host of the base URL is in the protection space
   */
  if ([domains count] == 0)
    {
      domains = [NSArray arrayWithObject: @"/"];
    }

  [storeLock lock];
  NS_DURING
    {
      NSEnumerator	*e = [domains objectEnumerator];
      NSString		*domain;

      while ((domain = [e nextObject]) != nil)
	{
	  NSURL			*u;
	  NSString		*path;
	  NSNumber		*port;
	  NSString		*scheme;
	  NSString		*server;
	  NSMutableDictionary	*sDict;

	  u = [NSURL URLWithString: domain];
	  scheme = [u scheme];
	  if (scheme == nil)
	    {
	      u = [NSURL URLWithString: domain relativeToURL: base];
	      scheme = [u scheme];
	    }
	  port = [u port];
	  if ([port intValue] == 80 && [scheme isEqualToString: @"http"])
	    {
	      port = nil;
	    }
	  else if ([port intValue] == 443 && [scheme isEqualToString: @"https"])
	    {
	      port = nil;
	    }
	  path = [u path];
	  if (path == nil)
	    {
	      path = @"";
	    }
	  if ([port intValue] == 0)
	    {
	      server = [NSString stringWithFormat: @"%@://%@",
		scheme, [u host]];
	    }
	  else
	    {
	      server = [NSString stringWithFormat: @"%@://%@:%@",
		scheme, [u host], port];
	    }
	  sDict = [domainMap objectForKey: server];
	  if (sDict == nil)
	    {
	      sDict = [NSMutableDictionary new];
	      [domainMap setObject: sDict forKey: server];
	      RELEASE(sDict);
	    }
	  [sDict setObject: space forKey: path];
	}
    }
  NS_HANDLER
    {
      [storeLock unlock];
      [localException raise];
    }
  NS_ENDHANDLER
  [storeLock unlock];
}

- (NSString*) authorizationForAuthentication: (NSString*)authentication
				      method: (NSString*)method
					path: (NSString*)path
{
  NSMutableString	*authorisation;

  if ([self->_space authenticationMethod]
    == NSURLAuthenticationMethodHTTPDigest)
    {
      NSString		*realm = nil;
      NSString		*qop = nil;
      NSString		*nonce = nil;
      NSString		*opaque = nil;
      NSString		*stale = @"FALSE";
      NSString		*algorithm = @"MD5";
      NSString		*cnonce;
      NSString		*HA1;
      NSString		*HA2;
      NSString		*response;
      int		nc;

      if (authentication != nil)
	{
	  NSScanner		*sc;
	  NSString		*key;
	  NSString		*val;

	  sc = [NSScanner scannerWithString: authentication];
	  if ([sc scanString: @"Digest" intoString: 0] == NO)
	    {
	      NSDebugMLog(@"Bad format HTTP digest in '%@'", authentication);
	      return nil;	// Not a digest authentication
	    }
	  while ((key = [mimeParser scanName: sc]) != nil)
	    {
	      if ([sc scanString: @"=" intoString: 0] == NO)
		{
		  NSDebugMLog(@"Missing '=' in HTTP digest '%@'",
		    authentication);
		  return nil;	// Bad name=value specification
		}
	      if ((val = [mimeParser scanToken: sc]) == nil)
		{
		  NSDebugMLog(@"Missing value in HTTP digest '%@'",
		    authentication);
		  return nil;	// Bad name=value specification
		}
	      if ([key caseInsensitiveCompare: @"realm"] == NSOrderedSame)
		{
		  realm = val;
		}
	      if ([key caseInsensitiveCompare: @"qop"] == NSOrderedSame)
		{
		  qop = val;
		}
	      if ([key caseInsensitiveCompare: @"nonce"] == NSOrderedSame)
		{
		  nonce = val;
		}
	      if ([key caseInsensitiveCompare: @"opaque"] == NSOrderedSame)
		{
		  opaque = val;
		}
	      if ([key caseInsensitiveCompare: @"stale"] == NSOrderedSame)
		{
		  stale = val;
		}
	      if ([key caseInsensitiveCompare: @"algorithm"] == NSOrderedSame)
		{
		  algorithm = val;
		}
	      if ([sc scanString: @"," intoString: 0] == NO)
		{
		  break;	// No more in list.
		}
	    }

	  if (realm == nil)
	    {
	      NSDebugMLog(@"Missing HTTP digest realm in '%@'", authentication);
	      return nil;
	    }
	  if ([realm isEqualToString: [self->_space realm]] == NO)
	    {
	      NSDebugMLog(@"Bad HTTP digest realm in '%@'", authentication);
	      return nil;
	    }
	  if (nonce == nil)
	    {
	      NSDebugMLog(@"Missing HTTP digest nonce in '%@'", authentication);
	      return nil;
	    }

	  if ([algorithm isEqualToString: @"MD5"] == NO)
	    {
	      NSDebugMLog(@"Unsupported HTTP digest algorithm in '%@'",
		authentication);
	      return nil;
	    }
	  if (![[qop componentsSeparatedByString: @","]
	    containsObject: @"auth"])
	    {
	      NSDebugMLog(@"Unsupported/missing HTTP digest qop in '%@'",
		authentication);
	      return nil;
	    }

	  [self->_lock lock];
	  if ([stale boolValue] == YES
	    || [nonce isEqualToString: _nonce] == NO)
	    {
	      _nc = 1;
	    }
	  ASSIGN(_nonce, nonce);
	  ASSIGN(_qop, qop);
	  ASSIGN(_opaque, opaque);
	}
      else
	{
	  [self->_lock lock];
	  nonce = _nonce;
	  opaque = _opaque;
	  realm = [self->_space realm];
	}

      nc = _nc++;

      qop = @"auth";

      cnonce = [[[[[NSProcessInfo processInfo] globallyUniqueString]
	dataUsingEncoding: NSUTF8StringEncoding] md5Digest] digestHex];

      HA1 = [[[[NSString stringWithFormat: @"%@:%@:%@",
	[self->_credential user], realm, [self->_credential password]]
	dataUsingEncoding: NSUTF8StringEncoding] md5Digest] digestHex];

      HA2 = [[[[NSString stringWithFormat: @"%@:%@", method, path]
	dataUsingEncoding: NSUTF8StringEncoding] md5Digest] digestHex];

      response = [[[[NSString stringWithFormat: @"%@:%@:%08x:%@:%@:%@",
	HA1, nonce, nc, cnonce, qop, HA2]
	dataUsingEncoding: NSUTF8StringEncoding] md5Digest] digestHex];

      authorisation = [NSMutableString stringWithCapacity: 512];
      [authorisation appendFormat:  @"Digest realm=\"%@\"", realm];
      [authorisation appendFormat:  @",username=\"%@\"",
	[self->_credential user]];
      [authorisation appendFormat:  @",nonce=\"%@\"", nonce];
      [authorisation appendFormat:  @",uri=\"%@\"", path];
      [authorisation appendFormat:  @",response=\"%@\"", response];
      [authorisation appendFormat:  @",qop=\"%@\"", qop];
      [authorisation appendFormat:  @",nc=%08x", nc];
      [authorisation appendFormat:  @",cnonce=\"%@\"", cnonce];
      if (opaque != nil)
	{
	  [authorisation appendFormat:  @",opaque=\"%@\"", opaque];
	}

      [self->_lock unlock];
    }
  else if ([self->_space authenticationMethod]
    == NSURLAuthenticationMethodHTMLForm)
    {
      // This should not generate any authentication header.
      return nil;
    }
  else if ([self->_space authenticationMethod]
    == NSURLAuthenticationMethodNTLM)
    {
      // FIXME: this needs to be implemented
      return nil;
    }
  else if ([self->_space authenticationMethod]
    == NSURLAuthenticationMethodNegotiate)
    {
      // FIXME: this needs to be implemented
      return nil;
    }
  else if ([self->_space authenticationMethod]
    == NSURLAuthenticationMethodDefault
    || [self->_space authenticationMethod]
    == NSURLAuthenticationMethodHTTPBasic)
    {
      NSString	*toEncode;

      if (authentication != nil)
	{
	  NSScanner		*sc;

	  sc = [NSScanner scannerWithString: authentication];
	  if ([sc scanString: @"Basic" intoString: 0] == NO)
	    {
	      NSDebugMLog(@"Bad format HTTP basic in '%@'", authentication);
	      return nil;	// Not a basic authentication
	    }
	}

      authorisation = [NSMutableString stringWithCapacity: 64];
      if ([[self->_credential password] length] > 0)
	{
	  toEncode = [NSString stringWithFormat: @"%@:%@",
	    [self->_credential user], [self->_credential password]];
	}
      else
	{
	  toEncode = [NSString stringWithFormat: @"%@",
	    [self->_credential user]];
	}
      [authorisation appendFormat: @"Basic %@",
	[GSMimeDocument encodeBase64String: toEncode]];
    }
  else
    {
      // FIXME: Currently, ClientCertificate and ServerTrust authentication
      // methods are NOT implemented and will end up here. They should, in fact,
      // be handled in the SSL connection layer (in GSHTTPURLHandle) rather than
      // in this method.
      return nil;
    }
  return authorisation;
}

- (NSURLCredential *) credential
{
  return self->_credential;
}

- (void) dealloc
{
  RELEASE(_credential);
  RELEASE(_space);
  RELEASE(_nonce);
  RELEASE(_opaque);
  RELEASE(_qop);
  RELEASE(_lock);
  [super dealloc];
}

- (id) initWithCredential: (NSURLCredential*)credential
	inProtectionSpace: (NSURLProtectionSpace*)space
{
  if ((self = [super init]) != nil)
    {
      self->_lock = [NSLock new];
      ASSIGN(self->_space, space);
      ASSIGN(self->_credential, credential);
    }
  return self;
}

- (NSURLProtectionSpace *) space
{
  return self->_space;
}
@end