#!/usr/bin/perl
# file: rdsamp             G. Moody        9 April 2000
#                         Last revised:    10 September 2004
# _____________________________________________________________________________
# CGI program to convert PhysioBank signals to text
# Copyright (C) 2000-2004 George B. Moody
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
# more details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#
# You may contact the author by e-mail (george@mit.edu) or postal mail
# (MIT Room E25-505A, Cambridge, MA 02139 USA).  For updates to this software,
# please visit PhysioNet (http://www.physionet.org/).
# _____________________________________________________________________________

use CGI qw/:standard/;
use CGI::Carp 'fatalsToBrowser';

$| = 1;

# _____________________________________________________________________________
# Read the list of databases and their descriptions (once only).
if (!$databases[0]) {
    read_dblist();
}

# Decide what is to be done next.
if (param) {
    $action = param('doit');  # the name of the button that was clicked, if any
}
else {
    $action = "Select database";  # default: choose a database on entry
}

if ($action eq "Select database") {
    choose_db();
}
else {  # database has been chosen; get list of records
    $database = param('database');
    if (!param('record')) {
	choose_record();
	$action = "Continue";
    }
    $record = param('record');
    if ($record =~ /.+\n/) {
	chop($record);
    }
    $tstart = param('tstart');
    $tend = param('tend');
    if ($action ne 'Continue') {
	output_results(); # depending on which button clicked, show or email
    }
}

# _____________________________________________________________________________
# Read the list of available databases.
sub read_dblist {
    $dblistfile = '/home/physionet/html/physiobank/database/DBS-with-signals';

    if (open(DBS,$dblistfile)) {
	@dblist = <DBS>;
	$i = 0;
	foreach $d (@dblist) {
	    @fields = split(/\t+/,$d);
	    chop($fields[1]);
	    $dblist[$i++] = $fields[0];
	    $dblabels{$fields[0]} = $fields[1] . " (" . $fields[0] . ")";
	}
    }
    else {
	@dblist = ('');
    }
}

# _____________________________________________________________________________
# Show the database choice form.
sub choose_db {
    print header, start_html(-dtd=>'-//IETF//DTD HTML//EN',
			     -bgcolor=>'white',-title=>'rdsamp-O-Matic');
    print_header();
    print start_form,
        table({-border=>0,-bgcolor=>'#d0d0ff',-width=>'100%'},
    		Tr({-align=>CENTER,-valign=>CENTER},
		   [
		    th('Database:'.
		       popup_menu(-name=>'database',
				  -value=>[@dblist],
				  -labels=>{%dblabels}).
		       submit(-name=>'doit',-value=>'Continue'))
		    ]
		   )),
	  end_form;
    print h2('rdsamp-O-Matic: Convert signals to text');
    print <<EOF;
<p>
The rdsamp-O-Matic allows you to convert binary signal files from PhysioBank
into text form.  Please choose a database from the list above, then click
on <em>Continue</em>.  Once you have done so, you will be able to choose a
record and the starting and ending times for the conversion.  You will be able
to view the text with your web browser, or you can have it sent to you via
e-mail.

<p>
To view the signals together with annotations (if available), try the
<a href="/cgi-bin/chart">Chart-O-Matic</a>.  To view annotations for these
signals (if available), including the times of occurrence and other attributes,
as text, try the <a href="/cgi-bin/rdann">rdann-O-Matic</a>.
<hr>
EOF
    print_footer();
}

# _____________________________________________________________________________
# Read the list of records for the chosen database.
sub read_rlist {
    $rlistfile = '/home/physionet/html/physiobank/database/' . $database .
	'/RECORDS';

    if (open(RECORDS,$rlistfile)) {
	@rlist = <RECORDS>;
    }
    else {
	@rlist = ('');
    }
}

# _____________________________________________________________________________
# Show the record/start/end choice form.
sub choose_record {
    read_rlist();
    print header, start_html(-dtd=>'-//IETF//DTD HTML//EN',
			     -bgcolor=>'white',-title=>'rdsamp-O-Matic');
    print_header();
    print start_form,
          table({-border=>0,-bgcolor=>'#d0d0ff',-width=>'100%'},
		Tr({-valign=>CENTER},
		   [
		    th({-align=>RIGHT},
		       'Database:') .
		    td({-align=>LEFT}, '<a href=/physiobank/database/' .
		       $database . "/>" . $dblabels{$database} . "</a>",
		       submit(-name=>'doit', -value=>'Select database')),

		    th({-align=>RIGHT},'Record:') .
		    td({-align=>LEFT}, popup_menu(-name=>'record',
						 -value=>[@rlist])) .
		    td({-align=>RIGHT}, '<a href=/cgi-bin/chart?database=' .
		       $database . '&tstart=' . $tstart .
		       '&width=medium>View signals</a>'),

		    th({-align=>RIGHT},'Start time:') .
		    td({-align=>LEFT},textfield(-name=>'tstart',
						-size=>40, -value=>'0')),

		    th({-align=>RIGHT},'End time:') .
		    td({-align=>LEFT},textfield(-name=>'tend',
						-size=>40,
                      -value=>'end of record, or 1 minute after start time')),

		    td({-align=>RIGHT},
		       submit(-name=>'doit',-value=>'Show samples')) .
		    td({-align=>LEFT},submit(-name=>'doit',
					     -value=>'E-mail samples to:'),
		       textfield(-name=>'email',-size=>20)) .
		    td({-align=>RIGHT},submit(-name=>'doit',
					      -value=>'rdsamp-O-Matic Help'))
		    ]
		   )),
	  hidden(-name=>'database',-value=>$database),
          end_form;
}

# _____________________________________________________________________________
# Show instructions for filling in the record choice form.
sub print_help {
    print h2('rdsamp-O-Matic: Convert signals to text');
    print <<EOF;
<p> Please choose a record from the list above.  In the start time
field, enter the elapsed time from the beginning of the record, in
<em>hh:mm:ss</em> format.  For example, to begin two minutes from the
beginning of the record, enter <tt>2:0</tt> in the start time field
(leading zero digits may be omitted).  Enter the end time in the same
format.  As a special case, use <tt>e</tt> or <tt>end</tt> in the end
time field to specify that you wish to list samples until the end of the
record. Note that the amount of output is limited to one minute per request
(depending on the sampling frequency and the number of signals, this can
be up to a megabyte of text). 

<p>
To view the requested data with your web browser, click on
<em>Show samples</em>.  Cut and paste the text or use the <em>Save</em>
or <em>Save As</em> features provided by your browser to copy the
output to a file on your disk. 

<p> To transmit the requested data via e-mail, enter
your e-mail address in the space provided above, then click on
<em>E-mail samples to:</em>.  The e-mail will be sent within a few
seconds, although your mail server may take a few minutes to transfer it
to your mailbox.  If you do not receive it within a reasonable time,
try specifying a shorter segment, since your mail server may reject very long
messages.

<p>
The output is generated by
<a href="/physiotools/wag/rdsamp-1.htm"><tt>rdsamp</tt></a>,
which is freely available in portable C source form and in precompiled binary
versions for several popular operating systems.  You may run <tt>rdsamp</tt>
on your own computer to convert signal files from PhysioNet and other sources
into text form. 
<hr>
EOF
}

# _____________________________________________________________________________
# Show or email the selected data.
sub output_results {
    choose_record();
    set_rdsamp_variables();
    if ($action eq 'rdsamp-O-Matic Help') {
	print_help();
	print_footer();
	return;
    }

    # Convert the selected data and save in a temporary file.
    $tfile = "/tmp/rdsamp.$$";
    unless (fork) {
	open(STDOUT, ">$tfile");
	exec("/usr/bin/rdsamp", "-r", $database . "/" . $record, "-f", $tstart,
			  "-t", $tend, "-p", "-v", "-l", "1:0");
    }
    # When rdsamp is finished, check if it wrote anything.
    wait;
    open(RDSAMP, $tfile);
    $samples = <RDSAMP>;
    if (!$samples) {
	print h1('No samples!');
	print <<EOF;
<p>
No samples were read.  This might occur if the record name
is incorrect, if the start or end time is improperly formatted, or if no
samples exist between the start and end times specified.  Please check
and correct your entries above.

<p>
If you are using one of the PhysioNet mirrors, it may not be able to convert
samples to text;  in this case, try using the <a href="http://www.physionet.org/cgi-bin/rdsamp">rdsamp-O-Matic on the master PhysioNet server</a>.
<hr>
EOF
        print_footer();
    }

    else {  # rdsamp was successful!
	if ($action eq 'E-mail samples to:') {
	    output_email();
	}
	else {
	    print '<pre>';
	    print $samples;
	    while ($samples = <RDSAMP>) {
		print $samples;
	    }
	    print '</pre>';
	}
    }
    unlink($tfile);
}

# _____________________________________________________________________________
# Set variables for the rdsamp command-line options.
sub set_rdsamp_variables {
    $database = param('database');
    $record = param('record');
    if ($record =~ /.+\n/) {
	chop($record);
    }
    $tstart = param('tstart');
    $tend = param('tend');

    if (!$database) {
	$database = "mitdb";
    }
    if (!$record) {
	$record = "100";
    }
    if (!$tstart) {
	$tstart = 0;
    }
    if (!$tend) {
	$tend = "end";
    }
    if (!$action) {
	$action = "Show samples";
    }
}

# _____________________________________________________________________________
# Send the output as email.
sub output_email {
    my $email = param('email');

    # Check that the user entered a plausible email address.
    if ($email =~ /^([-\w.]+)@([-\w]+)\.([-\w.]+)$/) {
	my $subject = 'Samples of record ' . $database . '/' . $record;
	system("/bin/mail -s '$subject' $email <$tfile");
	print h1('Data sent');
	print <<EOF;
<p>
The requested data have been sent to $email.
EOF
    }
    else {
	print h1('E-mail address needed');
	print <<EOF;
<p>
If you wish to transmit the requested data via e-mail, enter your e-mail
address in the space provided on the form, then click again on <em>E-mail
samples to:</em>.

<p>
If you wish to view the requested data with your web browser, click on
<em>Show samples</em>.
<hr>
EOF
    }
    print_footer();
}

# _____________________________________________________________________________
# Boilerplate header.
sub print_header {
    if (open(HEADER,"/home/physionet/html/links-physiobank.html")) {
	while (<HEADER>) {
	    print $_;
	}
    }
}

# _____________________________________________________________________________
# Boilerplate footer.
sub print_footer {
    print <<EOF;

<font size=-1><p>
Please e-mail your comments and suggestions to 
<a
href="mailto:webmaster\@physionet.org?subject=rdsamp-O-Matic"><tt>webmaster\@physionet.org</tt></a>, 
or post them to:
<p>
<i><address>
PhysioNet<br>
MIT Room E25-505A<br>
77 Massachusetts Avenue<br>
Cambridge, MA 02139 USA<br></address></i>
<p>
Updated Friday, 10 September 2004 at 11:28 EDT
</font>
EOF
    print end_html;
}