/**
 * Glitter Auto Update Object
 * Glitter is an automatic update class for your iPhone application.  It requires no package managers 
 * to be installed and thus is superior to other auto update classes available.
 *
 * (c) 2008 TheSpicyChicken
**/

#import "Glitter.h"

#define GlitterWorkDir [NSHomeDirectory() stringByAppendingPathComponent:@"Glitter"]
#define SystemOuputFile @"/tmp/glitter.out"

@implementation Glitter

- (id)initWithApplication:(UIApplication *)application URL:(NSString *)infoURL
{
	if ((self = [super init]))
	{
		_application = application;
		_infoURL = infoURL;
		_updateReady = NO;
		
		if (![[NSFileManager defaultManager] fileExistsAtPath:GlitterWorkDir])
		{
			NSLog(@"Creating Glitter working directory.");
			if (![[NSFileManager defaultManager] createDirectoryAtPath:GlitterWorkDir attributes:nil])
			{
				NSLog(@"Failed to create folder at %@",GlitterWorkDir);
				return NO;
			}
		}
	}
	return self;
}

- (BOOL)updateReady
{
	return _updateReady;
}

- (void)checkForUpdateNow
{
	[self checkForUpdateNow:nil];
}

/**
 * Intended to be called from thread.
**/
- (void)checkForUpdateNow:(NSDictionary *)updatePlist
{
	NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
	
	_updateReady = NO;
	
	if (updatePlist == nil) {
		updatePlist = [[self dictionaryAtURL:_infoURL] objectForKey:[_application version]];
	} else {
		updatePlist = [updatePlist objectForKey:[_application version]];
	}
	
	if (!updatePlist)
	{
		NSLog(@"An update record for version %@ was not found.",[_application version]);
		return;
	}
	
	if (![[updatePlist objectForKey:@"NeedsUpdate"] boolValue])
	{
		NSLog(@"No update necessary for version %@",[_application version]);
		return;
	}
	
	NSLog(@"Update required. Checking if already downloaded...");
	
	NSString *archiveName = [[updatePlist objectForKey:@"Archive"] lastPathComponent];
	NSString *pathToArchive = [NSString stringWithFormat:@"%@/%@",GlitterWorkDir,archiveName];
	BOOL download = YES;
	if ([[NSFileManager defaultManager] fileExistsAtPath:pathToArchive])
	{
		download = NO;
		NSLog(@"Download found.  Verifying checksum.");
		if (![self md5IsValid:pathToArchive md5:[updatePlist objectForKey:@"md5"]])
		{
			NSLog(@"Checksum is invalid, redownloading...");
			download = YES;
		}
	}
	
	if (download)
	{
		NSURL *archiveURL = [NSURL URLWithString:[updatePlist objectForKey:@"Archive"]];
		NSData *data = [NSData dataWithContentsOfURL:archiveURL];

		if ([data length] == 0)
		{
			NSLog(@"There was an error downloading the file from %@",archiveURL);
			return;
		}

		NSLog(@"Download complete. Saving to %@.",pathToArchive);

		if (![[NSFileManager defaultManager] createFileAtPath:pathToArchive contents:data attributes:nil]) {
			NSLog(@"There was an error creating %@",pathToArchive);
			return;
		}
	}
	
	if (![self md5IsValid:pathToArchive md5:[updatePlist objectForKey:@"md5"]])
	{
		NSLog(@"md5 hash is invalid.");
		return;
	}
	
	// Save class variables.
	_working = [[NSString stringWithFormat:@"%@/%@",GlitterWorkDir,[archiveName stringByDeletingPathExtension]] retain];
	_pathToArchive = [pathToArchive retain];
	_updatePlist = [updatePlist retain];
	
	_updateReady = YES;
	
	[pool release];
}

/**
 * Performs the installation process.
**/
- (void)install
{
	[self execute:[NSString stringWithFormat:@"unzip -q -o %@ -d %@",_pathToArchive,_working]];
	
	[self executeInstallationScript:[_updatePlist objectForKey:@"Exec"] fromPath:_working];
	
	NSLog(@"Cleaning up.");
	NSLog(@"Deleting %@",_working);
	if (![[NSFileManager defaultManager] removeFileAtPath:_working handler:nil]) NSLog(@"Failed to delete working directory.");
	NSLog(@"Deleting %@",_pathToArchive);
	if (![[NSFileManager defaultManager] removeFileAtPath:_pathToArchive handler:nil]) NSLog(@"Failed to delete archive file.");
	
}

/**
 * Performs the actions described in the Exec Array.
**/
- (void)executeInstallationScript:(NSArray *)executeArray fromPath:(NSString *)working
{
	NSEnumerator *en = [executeArray objectEnumerator];
	NSDictionary *command;
	while ((command = [en nextObject]))
	{
		if ([[command objectForKey:@"Command"] isEqualToString:@"Move"])
		{
			NSString *from = [working stringByAppendingPathComponent:[command objectForKey:@"From"]];
			NSString *to = [command objectForKey:@"To"];
			NSLog(@"Moving %@ to %@",from,to);
			[self copyFrom:from to:to];
		}
		
		if ([[command objectForKey:@"Command"] isEqualToString:@"System"])
		{
			NSLog(@"Executing system command: %@",[command objectForKey:@"Execute"]);
			[self execute:[command objectForKey:@"Execute"]];
		}
	}
}


- (NSDictionary *)dictionaryAtURL:(NSString *)urlString
{
	urlString = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL, 
	       (CFStringRef)urlString, NULL, NULL, 
				CFStringConvertNSStringEncodingToEncoding(NSASCIIStringEncoding));
	NSURL *url = [NSURL URLWithString:urlString];
	if (!url) {
		NSLog(@"Error building url %@ %@",url,urlString);
	}
	NSDictionary *tmp = [[NSDictionary alloc] initWithContentsOfURL:url];
	return tmp;
}

- (BOOL)md5IsValid:(NSString *)pathToArchive md5:(NSString *)md5
{
	NSString *cmd = [NSString stringWithFormat:@"/sbin/md5 %@ > %@",pathToArchive,SystemOuputFile];
	[self execute:cmd];
	NSString *result = [[NSString stringWithContentsOfFile:SystemOuputFile encoding:NSUTF8StringEncoding error:NULL] substringToIndex:32];
	
	if ([result isEqualToString:md5]) return YES;
	
	return NO;
}

- (int)execute:(NSString *)command
{
	NSLog(@"Executing %@",command);
	return system([command UTF8String]);
}

- (void)copyFrom:(NSString *)from to:(NSString *)to
{
	BOOL isDir;
	if ([[NSFileManager defaultManager] fileExistsAtPath:from isDirectory:&isDir])
	{
		if (isDir) [self copyFolderAtPath:from toPath:to];
		else [self copyFileAtPath:from toPath:to];
	}
}

/**
 * Copy file.
**/
- (void)copyFileAtPath:(NSString *)from toPath:(NSString *)to
{
	NSData *sourceData = [NSData dataWithContentsOfFile:from];
	if ([sourceData length] > 0)
	{
		if (![[NSFileManager defaultManager] createFileAtPath:to contents:sourceData attributes:nil])
			NSLog(@"There was an error copying from %@ to %@",from,to);
	}
}

/**
 * This is the only way I can think of to copy a directory tree recursively.
 * since when I try to use "mv" I get a permission denied error.
**/
- (void)copyFolderAtPath:(NSString *)from toPath:(NSString *)to
{
	if (![[NSFileManager defaultManager] fileExistsAtPath:to])
	{
		if (![[NSFileManager defaultManager] createDirectoryAtPath:to attributes:nil])
		{
			NSLog(@"There was an error when attempting to create directory at %@",to);
		}
	}
	
	NSArray *directoryContents = [[NSFileManager defaultManager] directoryContentsAtPath:from];
	NSEnumerator *en = [directoryContents objectEnumerator];
	NSString *object;
	
	while ((object = [en nextObject]))
	{
		NSString *fromPath = [from stringByAppendingPathComponent:object];
		NSString *toPath = [to stringByAppendingPathComponent:object];
		
		BOOL isDirectory;
		if ([[NSFileManager defaultManager] fileExistsAtPath:fromPath isDirectory:&isDirectory])
		{
			if (isDirectory)
			{
				[self copyFolderAtPath:fromPath toPath:toPath];
			} else {
				[self copyFileAtPath:fromPath toPath:toPath];
			}
		}
	}
}

@end