#!/usr/bin/perl -w
#
#	randastro
#
#	Create a csv file of all of the Astronomy Picture of the Day
#	images from the start until present.
#
#	This is typically called out from the user's crontab with something like:
#	    30 5 * * * .../randastro ~/.rootwindow/randastro2.csv
#

use strict;
use LWP::Simple;

use vars qw($BaseURL %Csv $NFetch $SYear $SMon $SDay $Version);

$BaseURL = 'http://antwrp.gsfc.nasa.gov/apod';
$Version = 'randastro v0.01 regan@ao.com';

$SYear	= 95;
$SMon	=  6;
$SDay	= 20;
$NFetch	= 20;		# Don't get too many images in a single run

###
###	Main program
###

    my($day, $day2, $fetch, @fields, $mon, $mon2, @montab, @tm,
    		$urlhtml, $year, $year2);

    # Read the existing CSV file
    #		url,0,0,url.html
    if (!defined($ARGV[0]))
    	{
	print "Usage: randastro file.csv\n";
	exit 1;
	}
    if (open(CSV, "<$ARGV[0]"))
    	{
	while (<CSV>)
	    {
	    chomp;
	    @fields = split(',', $_);
	    $Csv{$fields[3]} = $fields[0];
	    }
	}

    # Cycle through all possible URLs
    @montab = qw(31 28 31 30 31 30 31 31 30 31 30 31);

    @tm = localtime();
    $fetch = 0;
    for ($year = 95; $year <= $tm[5] && $fetch < $NFetch; $year++)
    	{
	$montab[1] = ((($year + 1900) % 4) == 0) ? 29 : 28;
	for ($mon = 0; $mon < 12; $mon++)
	    {
	    for ($day = 1; $day < 32 && $fetch < $NFetch; $day++)
	    	{
		# If this isn't a valid day, recycle
		last if ($day > $montab[$mon]);

		# If this is >= today, we quit
		$fetch = $NFetch
		    if ($year == $tm[5] && $mon == $tm[4] && $day == $tm[3]);

		# If this is < start, recycle
		next if ($year == $SYear &&
			 (($mon + 1) < $SMon) ||
			 (($mon + 1) == $SMon && $day < $SDay));

                next if ($year % 100 == 6 && $mon + 1 == 5 && $day == 29);
		$urlhtml = sprintf "$BaseURL/ap%02d%02d%02d.html",
						$year % 100, $mon + 1, $day;
                #print "Checking $urlhtml\n";

		if (!defined($Csv{$urlhtml}))
		    {
		    NewImage($urlhtml);
		    $fetch++;
		    }
		}
	    }
	}

    # Write new csv file.
    open(CSV, ">$ARGV[0]") || die "Cannot open $ARGV[0] for write: $!";
    for $urlhtml (sort keys %Csv)
    	{
	print CSV "$Csv{$urlhtml},0,0,$urlhtml\n";
	}
    close CSV;


###
###	NewImage
###
###	Get a new image file based upon the URL.
###
sub NewImage
    {
    my($url) = @_;
    my($data, $newurl);

    print "Fetch $url\n";
    $data = get($url);
    if (defined($data) && length($data) > 0 &&
    		$data =~ /img src\s*=\s*"(.*?)"/im)
    	{
	$newurl = "$BaseURL/$1";
	print "Url is $newurl\n";
        if ($data =~ m#a href="(image/.*?)"#im)
            {
            $newurl = "$BaseURL/$1";
            print "Use high resolution url of $newurl\n";
            }
	$Csv{$url} = $newurl;
	}
    }