#import <Foundation/Foundation.h>
#import <Quartz/Quartz.h>
#import <ScreenSaver/ScreenSaver.h>

// cmd = "System/Library/Printers/Libraries/./quartzfilter '%s' '%s' '%s'" % (pdffilepath, qfilterpath, tmpfilepath)

// Returns the file path of an unused temporary file
NSString *getTempFilePath (NSString *extension) {
	NSString *tempDirectory = NSTemporaryDirectory();
	NSFileManager *fileManager = [NSFileManager defaultManager];
	NSString *tempFilePath;
	BOOL pathExists = YES;
	while (pathExists == YES) {
		// creating a random integer between 1000 and 9999 with
		// a convenient function found in the ScreenSaver framework
		int randnum = SSRandomIntBetween(1000, 9999);
		// e.g. /TemporaryDirectory/8765.png
		tempFilePath = [NSString stringWithFormat:@"%@%d.%@", tempDirectory, randnum, extension];
		if ([fileManager fileExistsAtPath:tempFilePath] == NO) {
			pathExists = NO;
		}
	}
	// tempFilePath is an autoreleased object (created with NSSString stringWithFormat)
	return tempFilePath;
}

//
void printUsage () {
	printf("Usage: mergepdf -output [PDF path] -folder [PDF folder path] -qfilter [Quartz filter path]\n");
}

//
int sortPDFNames(id pdfName1, id pdfName2, void * context)
{
	return [pdfName1 compare:pdfName2 options:NSLiteralSearch];
}

int main (int argc, const char * argv[]) {
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
	NSFileManager *fileManager = [NSFileManager defaultManager];
	NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
	NSString *outputPath = [userDefaults stringForKey:@"output"];
	if ((outputPath == NULL) || ([outputPath isEqualToString:@""])) {
		printf("ERROR: Missing or invalid output path\n");
		printUsage();
		return 1;
	}
	BOOL applyQuartzFilter;
	BOOL isDir;
	NSString *quartzFilterPath = [userDefaults stringForKey:@"qfilter"];
	if (quartzFilterPath == NULL) {
		applyQuartzFilter = NO;
	} else {
		if ([quartzFilterPath isEqualToString:@""]) {
			printf("ERROR: Missing Quartz filter path\n");
			printUsage();
			return 1;
		} else {
			if ([fileManager fileExistsAtPath:quartzFilterPath] == NO) {
				NSLog(@"Quartz filter path does not exist");
				printf("ERROR: The Quartz filter does not exist:\n%s\n", [quartzFilterPath UTF8String]);
				return 1;
			}
		}
		applyQuartzFilter = YES;
	}

	NSString *folderPath = [userDefaults stringForKey:@"folder"];
	if ((folderPath == NULL) || ([folderPath isEqualToString:@""])) {
		printf("ERROR: Missing or invalid folder path\n");
		printUsage();
		return 1;
	}
	if ([fileManager fileExistsAtPath:folderPath isDirectory:&isDir] == NO) {
		printf("ERROR: The folder does not exist:\n%s\n", [folderPath UTF8String]);
		return 1;
	} else {
		if (isDir == NO) {
			printf("ERROR: The given path does not point to a folder:\n%s\n", [folderPath UTF8String]);
			return 1;
		}
	}
	NSArray *itemNames = [fileManager directoryContentsAtPath:folderPath];
	if ([itemNames count] == 0) {
		printf("ERROR: The given folder path is empty:\n%s\n", [folderPath UTF8String]);
	}

	NSMutableArray *pdfPaths = [[NSMutableArray alloc] initWithCapacity:1];
	NSEnumerator *itemNamesEnumerator = [itemNames objectEnumerator];
	NSString *itemName;
	while (itemName = [itemNamesEnumerator nextObject]) {
		// ignoring invisible items
		if ([itemName characterAtIndex:0] == '.') {
			continue;
		}
		// ignoring directories
		NSString *itemPath = [folderPath stringByAppendingPathComponent:itemName];
		BOOL isDir;
		if ([fileManager fileExistsAtPath:itemPath isDirectory:&isDir] == YES) {
			if (isDir == YES) {
				continue;
			}
			// simply discovering PDf files by a .pdf suffix :-)
			if ([itemName hasSuffix:@".pdf"]) {
				[pdfPaths addObject:itemPath];
			}
		}
	}
	if ([pdfPaths count] == NO) {
		printf("ERROR: No PDF files found in the given folder:\n%s\n", [folderPath UTF8String]);
		return 1;
	}
	printf("Found %i PDF documents in folder '%s'\n", [pdfPaths count], [folderPath UTF8String]);
	printf("Sorting found PDF document names alphabetically...\n");
	NSMutableArray *pdfNames = [[NSMutableArray alloc] initWithCapacity:1];
	NSEnumerator *pdfPathsEnumerator = [pdfPaths objectEnumerator];
	NSString *pdfPath;
	while (pdfPath = [pdfPathsEnumerator nextObject]) {
		NSString *pdfName = [pdfPath lastPathComponent];
		[pdfNames addObject:pdfName];
	}
	[pdfPaths release];
	NSArray *sortedPDFNames = [pdfNames sortedArrayUsingFunction:sortPDFNames context:NULL];
	PDFDocument *outputPDF;
	outputPDF = [[PDFDocument alloc] init];
	if (outputPDF == NULL) {
		NSBundle *myBundle = [NSBundle mainBundle];
		NSString *parentFolderPath = [myBundle bundlePath];
		NSString *dummyPDFPath = [parentFolderPath stringByAppendingPathComponent:@"dummy.pdf"];
		if ([fileManager fileExistsAtPath:dummyPDFPath] == NO) {
			printf("ERROR: Cannot load dummy PDF file supposed to be located at:\n%s\n", [dummyPDFPath UTF8String]);
			return 1;
		} else {
			NSURL *dummyPDFURL = [NSURL fileURLWithPath:dummyPDFPath];
			outputPDF = [[PDFDocument alloc] initWithURL:dummyPDFURL];
			if (outputPDF == NULL) {
				printf("ERROR: Could not initialize new PDF document\n");
				return 1;
			}
			[outputPDF removePageAtIndex:0];
		}
	}
	PDFDocument *inputPDF;
	int pagecounter = 0;
	NSEnumerator *pdfNamesEnumerator = [sortedPDFNames objectEnumerator];
	NSString *pdfName;
	while (pdfName = [pdfNamesEnumerator nextObject]) {
		NSString *pdfPath = [folderPath stringByAppendingPathComponent:pdfName];
		NSURL *pdfURL = [NSURL fileURLWithPath:pdfPath];
		inputPDF = [[PDFDocument alloc] initWithURL:pdfURL];
		if (inputPDF == NULL) {
			printf("ERROR: The file does not seem to be a valid PDF:\n\%s\n", [pdfPath UTF8String]);
			continue;
		}
		int pagecount = [inputPDF pageCount];
		printf("Processing PDF document: %s (Pages: %i)\n", [pdfName UTF8String], pagecount);
		int pagenum;
		for( pagenum = 0; pagenum < pagecount; pagenum++ ) {
			printf("\tAdding page %i\n", (pagenum + 1));
			PDFPage *singlePage = [inputPDF pageAtIndex:pagenum];
			[outputPDF insertPage:singlePage atIndex:pagecounter];
			pagecounter++;
		}
	}
	[pdfNames release];
	if (applyQuartzFilter == YES) {
		printf("Applying Quartz filter: %s\n", [quartzFilterPath UTF8String]);
		NSString *tmpFilePath = getTempFilePath(@"pdf");
		BOOL tmpWriteSuccess = [outputPDF writeToFile:tmpFilePath];
		if (tmpWriteSuccess == NO) {
			printf("ERROR: Could not write PDF content to temporary file.\n");
			return 1;
		}
		NSTask *shellCommand = [[NSTask alloc] init];
		[shellCommand setLaunchPath:@"/System/Library/Printers/Libraries/./quartzfilter"];
		// arrayWithObjects expects nil as the last object
		[shellCommand setArguments:[NSArray arrayWithObjects:tmpFilePath, quartzFilterPath, outputPath, nil]];
		[shellCommand launch];
		[shellCommand waitUntilExit];
		int shellCommandStatus = [shellCommand terminationStatus];
		if (shellCommandStatus != 0) {
			printf("ERROR: The quartzfilter utility did not run successfully\n");
			return 1;
		}
		[shellCommand release];
		[fileManager removeFileAtPath:tmpFilePath handler:NULL];
		printf("Created the new PDF (%i pages): '%s'\n", pagecounter, [outputPath UTF8String]);
	} else {
		printf("Writing the new PDF (%i pages): '%s'\n", pagecounter, [outputPath UTF8String]);
		BOOL writeSuccess = [outputPDF writeToFile:outputPath];
		if (writeSuccess == NO) {
			printf("ERROR: Could not write PDF file:\n%s\n", [outputPath UTF8String]);
			return 1;
		}
	}
	[outputPDF release];
	[inputPDF release];
    [pool drain];
    return 0;
}