/*

  * The AutoHyperlinks Framework is the legal property of its developers (DEVELOPERS), whose names are listed in the

  * copyright file included with this source distribution.

  *

  * 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 name of the AutoHyperlinks Framework nor the

  *       names of its contributors may be used to endorse or promote products

  *       derived from this software without specific prior written permission.

  *

  * THIS SOFTWARE IS PROVIDED BY ITS DEVELOPERS ``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 ITS DEVELOPERS 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 "AHHyperlinkScanner.h"

 #import "AHLinkLexer.h"

 #import "AHMarkedHyperlink.h"

 #define	DEFAULT_URL_SCHEME	@"http://"

 #define ENC_INDEX_KEY @"encIndex"

 #define ENC_CHAR_KEY @"encChar"

 @interface AHHyperlinkScanner (PRIVATE)

 - (NSRange)_longestBalancedEnclosureInRange:(NSRange)inRange;

 - (BOOL)_scanString:(NSString *)inString upToCharactersFromSet:(NSCharacterSet *)inCharSet intoRange:(NSRange *)outRangeRef fromIndex:(unsigned long *)idx;

 - (BOOL)_scanString:(NSString *)inString charactersFromSet:(NSCharacterSet *)inCharSet intoRange:(NSRange *)outRangeRef fromIndex:(unsigned long *)idx;

 @end

 @implementation AHHyperlinkScanner

 #pragma mark static variables

 	static NSCharacterSet	*skipSet = nil;

 	static NSCharacterSet	*endSet = nil;

 	static NSCharacterSet	*startSet = nil;

 	static NSCharacterSet	*puncSet = nil;

 	static NSCharacterSet	*hostnameComponentSeparatorSet = nil;

 	static NSArray			*enclosureStartArray = nil;

 	static NSCharacterSet	*enclosureSet = nil;

 	static NSArray			*enclosureStopArray = nil;

 	static NSArray			*encKeys = nil;

 #pragma mark Class Methods

 + (id)hyperlinkScannerWithString:(NSString *)inString

 {

 	return [[[[self class] alloc] initWithString:inString usingStrictChecking:NO] autorelease];

 }

 + (id)strictHyperlinkScannerWithString:(NSString *)inString

 {

 	return [[[[self class] alloc] initWithString:inString usingStrictChecking:YES] autorelease];

 }

 + (id)hyperlinkScannerWithAttributedString:(NSAttributedString *)inString

 {

 	return [[[[self class] alloc] initWithAttributedString:inString usingStrictChecking:NO] autorelease];

 }

 + (id)strictHyperlinkScannerWithAttributedString:(NSAttributedString *)inString

 {

 	return [[[[self class] alloc] initWithAttributedString:inString usingStrictChecking:NO] autorelease];

 }

 #pragma mark Initialization

 + (void)initialize

 {

 	if ((self == [AHHyperlinkScanner class])) {

 		if (!skipSet) {

 			NSMutableCharacterSet *mutableSkipSet = [[NSMutableCharacterSet alloc] init];

 			[mutableSkipSet formUnionWithCharacterSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

 			[mutableSkipSet formUnionWithCharacterSet:[NSCharacterSet illegalCharacterSet]];

 			[mutableSkipSet formUnionWithCharacterSet:[NSCharacterSet controlCharacterSet]];

 			[mutableSkipSet formUnionWithCharacterSet:[NSCharacterSet characterSetWithCharactersInString:@"<>"]];

 			skipSet = [[NSCharacterSet characterSetWithBitmapRepresentation:[mutableSkipSet bitmapRepresentation]] retain];

 			[mutableSkipSet release];

 		}

 		if (!endSet) {

 			endSet = [[NSCharacterSet characterSetWithCharactersInString:@"\"',:;>)]}.?!@"] retain];

 		}

 		if (!startSet) {

 			NSMutableCharacterSet *mutableStartSet = [[NSMutableCharacterSet alloc] init];

 			[mutableStartSet formUnionWithCharacterSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

 			[mutableStartSet formUnionWithCharacterSet:[NSCharacterSet characterSetWithCharactersInString:[NSString stringWithFormat:@"\"'.,:;<?!-@%C%C", 0x2014, 0x2013]]];

 			startSet = [[NSCharacterSet characterSetWithBitmapRepresentation:[mutableStartSet bitmapRepresentation]] retain];

 			[mutableStartSet release];

 		}

 		if (!puncSet) {

 			puncSet = [[NSCharacterSet characterSetWithCharactersInString:@"\"'.,:;<?!"] retain];

 		}

 		if (!hostnameComponentSeparatorSet) {

 			hostnameComponentSeparatorSet = [[NSCharacterSet characterSetWithCharactersInString:@"./"] retain];

 		}

 		if(!enclosureStartArray){

 			enclosureStartArray = [[NSArray arrayWithObjects:@"(",@"[",@"{",nil] retain];

 		}

 		if(!enclosureSet){

 			enclosureSet = [[NSCharacterSet characterSetWithCharactersInString:@"()[]{}"] retain];

 		}

 		if(!enclosureStopArray){

 			enclosureStopArray = [[NSArray arrayWithObjects:@")",@"]",@"}",nil] retain];

 		}

 		if(!encKeys){

 			encKeys = [[NSArray arrayWithObjects:ENC_INDEX_KEY, ENC_CHAR_KEY, nil] retain];

 		}		

 	}

 }

 #pragma mark Init/Dealloc

 - (id)initWithString:(NSString *)inString usingStrictChecking:(BOOL)flag

 {

 	if((self = [self init])){

 		m_scanString = [inString retain];

 		m_scanAttrString = nil;

 		m_urlSchemes = [[NSDictionary alloc] initWithObjectsAndKeys:

 			@"ftp://", @"ftp",

 			nil];

 		m_strictChecking = flag;

 		m_scanLocation = 0;

 		m_scanStringLength = [m_scanString length];

 	}

 	return self;

 }

 - (id)initWithAttributedString:(NSAttributedString *)inString usingStrictChecking:(BOOL)flag

 {

 	if((self = [self init])){

 		m_scanString = [[inString string] retain];

 		m_scanAttrString = [inString retain];

 		m_urlSchemes = [[NSDictionary alloc] initWithObjectsAndKeys:

 			@"ftp://", @"ftp",

 			nil];

 		m_strictChecking = flag;

 		m_scanLocation = 0;

 		m_scanStringLength = [m_scanString length];

 	}

 	return self;

 }

 - (void)dealloc

 {

 	[m_scanString release];

 	[m_urlSchemes release];

 	if(m_scanAttrString) [m_scanAttrString release];

 	[super dealloc];

 }

 #pragma mark URI Verification

 - (BOOL)isValidURI

 {

 	return [AHHyperlinkScanner isStringValidURI:m_scanString usingStrict:m_strictChecking fromIndex:nil withStatus:nil];

 }

 + (BOOL)isStringValidURI:(NSString *)inString usingStrict:(BOOL)useStrictChecking fromIndex:(unsigned long *)index withStatus:(AH_URI_VERIFICATION_STATUS *)validStatus

 {

     AH_BUFFER_STATE	 buf;  // buffer for flex to scan from

 	yyscan_t		 scanner; // pointer to the flex scanner opaque type

 	const char		*inStringEnc;

     unsigned long	 encodedLength;

 	if(!validStatus){

 		AH_URI_VERIFICATION_STATUS newStatus = AH_URL_INVALID;

 		validStatus = &newStatus;

 	}

 	*validStatus = AH_URL_INVALID; // assume the URL is invalid

 	// Find the fastest 8-bit wide encoding possible for the c string

 	NSStringEncoding stringEnc = [inString fastestEncoding];

 	if([@" " lengthOfBytesUsingEncoding:stringEnc] > 1U)

 		stringEnc = NSUTF8StringEncoding;

 	if (!(inStringEnc = [inString cStringUsingEncoding:stringEnc])) {

 		return NO;

 	}

 	encodedLength = strlen(inStringEnc); // length of the string in utf-8

 	// initialize the buffer (flex automatically switches to the buffer in this function)

 	AHlex_init(&scanner);

     buf = AH_scan_string(inStringEnc, scanner);

     // call flex to parse the input

     *validStatus = AHlex(scanner);

 	if(index) *index += AHget_leng(scanner);

     // condition for valid URI's

     if(*validStatus == AH_URL_VALID || *validStatus == AH_MAILTO_VALID || *validStatus == AH_FILE_VALID){

         AH_delete_buffer(buf, scanner); //remove the buffer from flex.

         buf = NULL; //null the buffer pointer for safty's sake.

         // check that the whole string was matched by flex.

         // this prevents silly things like "blah...com" from being seen as links

         if(AHget_leng(scanner) == encodedLength){

 			AHlex_destroy(scanner);

             return YES;

         }

     // condition for degenerate URL's (A.K.A. URI's sans specifiers), requres strict checking to be NO.

     }else if((*validStatus == AH_URL_DEGENERATE || *validStatus == AH_MAILTO_DEGENERATE) && !useStrictChecking){

         AH_delete_buffer(buf, scanner);

         buf = NULL;

         if(AHget_leng(scanner) == encodedLength){

 			AHlex_destroy(scanner);

             return YES;

         }

     // if it ain't vaild, and it ain't degenerate, then it's invalid.

     }else{

         AH_delete_buffer(buf, scanner);

         buf = NULL;

 		AHlex_destroy(scanner);

         return NO;

     }

     // default case, if the range checking above fails.

 	AHlex_destroy(scanner);

     return NO;

 }

 #pragma mark Accessors

 - (AHMarkedHyperlink *)nextURI

 {

 	NSRange	scannedRange;

 	unsigned long scannedLocation = m_scanLocation;

     // scan upto the next whitespace char so that we don't unnecessarity confuse flex

     // otherwise we end up validating urls that look like this "http://www.adiumx.com/ <--cool"

 	[self _scanString:m_scanString charactersFromSet:startSet intoRange:nil fromIndex:&scannedLocation];

 	// main scanning loop

 	while([self _scanString:m_scanString upToCharactersFromSet:skipSet intoRange:&scannedRange fromIndex:&scannedLocation]) {

 		BOOL foundUnpairedEnclosureCharacter = NO;

 		// Check for and filter enclosures.  We can't add (, [, etc. to the skipSet as they may be in a URI

 		if([enclosureSet characterIsMember:[m_scanString characterAtIndex:scannedRange.location]]){

 			unsigned long encIdx = [enclosureStartArray indexOfObject:[m_scanString substringWithRange:NSMakeRange(scannedRange.location, 1)]];

 			NSRange encRange;

 			if(NSNotFound != encIdx) {

 				encRange = [m_scanString rangeOfString:[enclosureStopArray objectAtIndex:encIdx] options:NSBackwardsSearch range:scannedRange];

 				if(NSNotFound != encRange.location){

 					scannedRange.location++; scannedRange.length -= 2;

 				}else{

 					foundUnpairedEnclosureCharacter = YES;

 				}

 			}

 		}

 		if(!scannedRange.length) break;

 		// Find balanced enclosure chars

 		NSRange longestEnclosure = [self _longestBalancedEnclosureInRange:scannedRange];

 		while (scannedRange.length > 2 && [endSet characterIsMember:[m_scanString characterAtIndex:(scannedRange.location + scannedRange.length - 1)]]) {

 			if((longestEnclosure.location + longestEnclosure.length) < scannedRange.length){

 				scannedRange.length--;

 				foundUnpairedEnclosureCharacter = NO;

 			}else break;

 		}

         // if we have a valid URL then save the scanned string, and make a SHMarkedHyperlink out of it.

         // this way, we can preserve things like the matched string (to be converted to a NSURL),

         // parent string, its validation status (valid, file, degenerate, etc), and its range in the parent string

 		AH_URI_VERIFICATION_STATUS	 validStatus;

 		NSString					*_scanString = nil;

 		if(3 < scannedRange.length) _scanString = [m_scanString substringWithRange:scannedRange];

         if((3 < scannedRange.length) && [[self class] isStringValidURI:_scanString usingStrict:m_strictChecking fromIndex:&m_scanLocation withStatus:&validStatus]){

             AHMarkedHyperlink	*markedLink;

             //insert typical specifiers if the URL is degenerate

             switch(validStatus){

                 case AH_URL_DEGENERATE:

                 {

                     NSString *scheme = DEFAULT_URL_SCHEME;

 					unsigned long i = 0;

                     NSRange  firstComponent;

 					[self		  _scanString:_scanString

 						upToCharactersFromSet:hostnameComponentSeparatorSet

 									intoRange:&firstComponent

 									fromIndex:&i];

                     if(NSNotFound != firstComponent.location) {

                     	NSString *hostnameScheme = [m_urlSchemes objectForKey:[_scanString substringWithRange:firstComponent]];

                     	if(hostnameScheme) scheme = hostnameScheme;

                     }

                     _scanString = [scheme stringByAppendingString:_scanString];

                     break;

                 }

                 case AH_MAILTO_DEGENERATE:

 					_scanString = [@"mailto:" stringByAppendingString:_scanString];

                     break;

                 default:

                     break;

             }

             //make a marked link

             markedLink = [[[AHMarkedHyperlink alloc] initWithString:_scanString

 											  withValidationStatus:validStatus

 													  parentString:m_scanString

 														  andRange:scannedRange] autorelease];

             return [markedLink URL]? markedLink : nil;

         }

 		//step location after scanning a string

 		if (foundUnpairedEnclosureCharacter){

 			m_scanLocation++;

 		}else{

 			NSRange startRange = [m_scanString rangeOfCharacterFromSet:puncSet options:NSLiteralSearch range:scannedRange];

 			if (startRange.location != NSNotFound)

 				m_scanLocation = startRange.location + startRange.length;

 			else

 				m_scanLocation += scannedRange.length;

 		}

 		scannedLocation = m_scanLocation;

     }

     // if we're here, then NSScanner hit the end of the string

     // set AHStringOffset to the string length here so we avoid potential infinite looping with many trailing spaces.

     m_scanLocation = m_scanStringLength;

     return nil;

 }

 -(NSArray *)allURIs

 {

     NSMutableArray		*rangeArray = [NSMutableArray array];

     AHMarkedHyperlink	*markedLink;

 	unsigned long		 _holdOffset = m_scanLocation; // store location for later restoration;

 	m_scanLocation = 0; //set the offset to 0.

     //build an array of marked links.

 	while((markedLink = [self nextURI])){

 		[rangeArray addObject:markedLink];

 	}

     m_scanLocation = _holdOffset; // reset scanLocation

 	return rangeArray;

 }

 -(NSAttributedString *)linkifiedString

 {

 	NSMutableAttributedString	*linkifiedString;

 	AHMarkedHyperlink			*markedLink;

 	BOOL						_didFindLinks = NO;

 	unsigned long				_holdOffset = m_scanLocation; // store location for later restoration;

 	m_scanLocation = 0;

 	if(m_scanAttrString) {

 		linkifiedString = [[m_scanAttrString mutableCopy] autorelease];

 	} else {

 		linkifiedString = [[[NSMutableAttributedString alloc] initWithString:m_scanString] autorelease];

 	}

 	//for each SHMarkedHyperlink, add the proper URL to the proper range in the string.

 	while((markedLink = [self nextURI])) {

 		NSURL *markedLinkURL;

 		_didFindLinks = YES;

 		if((markedLinkURL = [markedLink URL])){

 			[linkifiedString addAttribute:NSLinkAttributeName

 									value:markedLinkURL

 									range:[markedLink range]];

 		}

 	}

 	m_scanLocation = _holdOffset; // reset scanLocation

 	return _didFindLinks? linkifiedString :

 						  m_scanAttrString ? [[m_scanAttrString retain] autorelease] : [[[NSMutableAttributedString alloc] initWithString:m_scanString] autorelease];

 }

 -(unsigned long)scanLocation

 {

 	return m_scanLocation;

 }

 - (void)setScanLocation:(unsigned int)location

 {

 	m_scanLocation = location;

 }

 #pragma mark Below Here There Be Private Methods

 - (NSRange)_longestBalancedEnclosureInRange:(NSRange)inRange

 {

 	NSMutableArray	*enclosureStack = nil, *enclosureArray = nil;

 	NSString  *matchChar = nil;

 	NSDictionary *encDict;

 	unsigned long encScanLocation = inRange.location;

 	while(encScanLocation < inRange.length + inRange.location) {

 		[self _scanString:m_scanString upToCharactersFromSet:enclosureSet intoRange:nil fromIndex:&encScanLocation];

 		if(encScanLocation >= (inRange.location + inRange.length)) break;

 		matchChar = [m_scanString substringWithRange:NSMakeRange(encScanLocation, 1)];

 		if([enclosureStartArray containsObject:matchChar]) {

 			encDict = [NSDictionary	dictionaryWithObjects:[NSArray arrayWithObjects:[NSNumber numberWithUnsignedLong:encScanLocation], matchChar, nil]

 												forKeys:encKeys];

 			if(!enclosureStack) enclosureStack = [NSMutableArray arrayWithCapacity:1];

 			[enclosureStack addObject:encDict];

 		}else if([enclosureStopArray containsObject:matchChar]) {

 			NSEnumerator *encEnumerator = [enclosureStack objectEnumerator];

 			while ((encDict = [encEnumerator nextObject])) {

 				unsigned long encTagIndex = [(NSNumber *)[encDict objectForKey:ENC_INDEX_KEY] unsignedLongValue];

 				unsigned long encStartIndex = [enclosureStartArray indexOfObjectIdenticalTo:[encDict objectForKey:ENC_CHAR_KEY]];

 				if([enclosureStopArray indexOfObjectIdenticalTo:matchChar] == encStartIndex) {

 					NSRange encRange = NSMakeRange(encTagIndex, encScanLocation - encTagIndex + 1);

 					if(!enclosureStack) enclosureStack = [NSMutableArray arrayWithCapacity:1];

 					if(!enclosureArray) enclosureArray = [NSMutableArray arrayWithCapacity:1];

 					[enclosureStack removeObject:encDict];

 					[enclosureArray addObject:NSStringFromRange(encRange)];

 					break;

 				}

 			}

 		}

 		if(encScanLocation < inRange.length + inRange.location)

 			encScanLocation++;

 	}

 	return (enclosureArray && [enclosureArray count])? NSRangeFromString([enclosureArray lastObject]) : NSMakeRange(0, 0);

 }

 // functional replacement for -[NSScanner scanUpToCharactersFromSet:intoString:]

 - (BOOL)_scanString:(NSString *)inString upToCharactersFromSet:(NSCharacterSet *)inCharSet intoRange:(NSRange *)outRangeRef fromIndex:(unsigned long *)idx

 {

 	unichar			_curChar;

 	NSRange			_outRange;

 	unsigned long	_scanLength = [inString length];

 	unsigned long	_idx;

 	if(_scanLength <= *idx) return NO;

 	// Asorb skipSet

 	for(_idx = *idx; _scanLength > _idx; _idx++) {

 		_curChar = [inString characterAtIndex:_idx];

 		if(![skipSet characterIsMember:_curChar]) break;

 	}

 	// scanUpTo:

 	for(*idx = _idx; _scanLength > _idx; _idx++) {

 		_curChar = [inString characterAtIndex:_idx];

 		if([inCharSet characterIsMember:_curChar] || [skipSet characterIsMember:_curChar]) break;

 	}

 	_outRange = NSMakeRange(*idx, _idx - *idx);

 	*idx = _idx;

 	if(_outRange.length) {

 		if(outRangeRef) *outRangeRef = _outRange;

 		return YES;

 	} else {

 		return NO;

 	}

 }

 // functional replacement for -[NSScanner scanCharactersFromSet:intoString:]

 - (BOOL)_scanString:(NSString *)inString charactersFromSet:(NSCharacterSet *)inCharSet intoRange:(NSRange *)outRangeRef fromIndex:(unsigned long *)idx

 {

 	unichar			_curChar;

 	NSRange			_outRange;

 	unsigned long	_scanLength = [inString length];

 	unsigned long	_idx = *idx;

 	if(_scanLength <= _idx) return NO;

 	// Asorb skipSet

 	for(_idx = *idx; _scanLength > _idx; _idx++) {

 		_curChar = [inString characterAtIndex:_idx];

 		if(![skipSet characterIsMember:_curChar]) break;

 	}

 	// scanCharacters:

 	for(*idx = _idx; _scanLength > _idx; _idx++) {

 		_curChar = [inString characterAtIndex:_idx];

 		if(![inCharSet characterIsMember:_curChar]) break;

 	}

 	_outRange = NSMakeRange(*idx, _idx - *idx);

 	*idx = _idx;

 	if(_outRange.length) {

 		if(outRangeRef) *outRangeRef = _outRange;

 		return YES;

 	} else {

 		return NO;

 	}

 }

 @end