#!/usr/bin/perl
# ------------------------------------------------------------------------------------
#  Program for downloading XPlanet cloud images from a random mirror
# 
#  Copyright (c) 2003, cueSim Ltd.                  http://www.cueSim.com, Bedford, UK
#  
# ------------------------------------------------------------------------------------
#  
#  Redistribution and use, 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.
#      * Neither the cueSim name 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 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.
# 


use LWP::Simple;

# Set options:
#  - where to save the downloaded file (default is current directory)
my $Filename = "/home/vlado/docs/xplanet/clouds_2048.jpg";

# - how often the image is updated on the server
my $MaxDownloadFrequencyHours = 2;

# - how many times to retry, if the server doesn't respond
my $MaxRetries = 3;

## Note: excessive requests to a single image server is discouraged.
## This script limits max retries, does not download more frequently
## than every two hours (the file is generated every 3 hours). and 
## picks a random mirror location for every download.
##
## Change these settings at the risk of being blacklisted from the
## image servers.
		
		
# Get file details
if(-f $Filename)
{
	my @Stats = stat($Filename);
	my $FileAge = (time() - $Stats[9]);
	my $FileSize = $Stats[7];

	# Check if file is already up to date
	if($FileAge < 60 * 60 * $MaxDownloadFrequencyHours && $FileSize > 10000)
	{
		print "File is already up to date\n";
		exit(1);	
	}
}


# Try several times to download the file if necessary
for(1..$MaxRetries)
{
	# Get a random website to hit for the file
	my $MirrorURL = GetRandomMirror("mirrors.txt");

	# Download the file
	print "Using $MirrorURL\nDownloading...\n";
	my $Response = getstore($MirrorURL, $Filename);

	# If successfully downloaded, that's it, nothing more to do
	if( IndicatesSuccess($Response))
	{
		print "Finished: file successfully downloaded to $Filename\n";
		# create cloud maps:
		exit(0);
	}
	
	# Warning that we're retrying another random server
	print "Download not available, trying another website\n\n";
}

# Warning that no servers could be contacted
print "ERROR: Tried to download the file $MaxRetries times, but no servers could provide the file\n";
exit(2);



# Return codes of 200 to 299 are "success" in HTTP-speak
sub IndicatesSuccess()
{
	my $Response = shift();
	if($Response =~ /2\d\d/)
	{
		return(1);
	}
	else
	{
		return(0);
	}
}

# Returns the name of an internet resource which can provide the clouds image
sub GetRandomMirror()
{
	# Populate a list of mirrors
	my @Mirrors = (
		       "http://xplanet.sourceforge.net/clouds/clouds_2048.jpg",
		       "ftp://mirror.pacific.net.au/xplanet/clouds_2048.jpg",
		       "http://www.ruwenzori.net/earth/clouds_2048.jpg",
		       "http://xplanet.dyndns.org/clouds/clouds_2048.jpg",
		       "http://userpage.fu-berlin.de/~jml/clouds_2048.jpg",
		       "ftp://ftp.iastate.edu/pub/xplanet/clouds_2048.jpg",
		       "http://www.wizabit.eclipse.co.uk/xplanet/files/mirror/clouds_2048.jpg");
# Fehler:
#		       "http://rcswww.urz.tu-dresden.de/~es179238/clouds_2048.jpg",
#		       "http://xplanet.arculeo.com/clouds_2048.jpg",
	
	# Return one at random
	return $Mirrors[rand scalar(@Mirrors)];
}
