###########################################################################
#
# printusage.pm --
# A component of the Greenstone digital library software
# from the New Zealand Digital Library Project at the 
# University of Waikato, New Zealand.
#
# Copyright (C) 1999 New Zealand Digital Library Project
#
# 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., 675 Mass Ave, Cambridge, MA 02139, USA.
#
###########################################################################


package PrintUsage;


sub print_xml_header
{
    print STDERR "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
    print STDERR "<!DOCTYPE Info [\n";
    print STDERR "  <!ELEMENT Info      (Name, Desc, Arguments)>\n";
    print STDERR "  <!ELEMENT Arguments (Option*)>\n";
    print STDERR "  <!ELEMENT Option    (Name, Desc, Type, Required, Default?, List?)>\n";
    print STDERR "  <!ELEMENT Name      (#PCDATA)>\n";
    print STDERR "  <!ELEMENT Desc      (#PCDATA)>\n";
    print STDERR "  <!ELEMENT Type      (#PCDATA)>\n";
    print STDERR "  <!ELEMENT Required  (#PCDATA)>\n";
    print STDERR "  <!ELEMENT Default   (#PCDATA)>\n";
    print STDERR "  <!ELEMENT List      (Value*)>\n";
    print STDERR "  <!ELEMENT Value     (Name, Desc?)>\n";
    print STDERR "]>\n\n";
}


sub print_options_xml
{
    local $options = shift(@_);

    foreach $option (@$options) {
	local $optionname = $option->{'name'};

	# Display option name, description and type
	print STDERR "    <Option>\n";
	print STDERR "      <Name>$optionname</Name>\n";
	print STDERR "      <Desc>$option->{'desc'}</Desc>\n";
	print STDERR "      <Type>$option->{'type'}</Type>\n";

	# If the option has a required field, display this
	if (defined($option->{'reqd'})) {
	    print STDERR "      <Required>$option->{'reqd'}</Required>\n";
	}

	# If the option has a list of possible values, display these
	if (defined $option->{'list'}) {
	    print STDERR "      <List>\n";
	    local $optionvalueslist = $option->{'list'};
	    foreach $optionvalue (@$optionvalueslist) {
		print STDERR "        <Value>\n";
		print STDERR "          <Name>$optionvalue->{'name'}</Name>\n";
		if (defined $optionvalue->{'desc'}) {
		    print STDERR "          <Desc>$optionvalue->{'desc'}</Desc>\n";
		}
		print STDERR "        </Value>\n";
	    }

	    # Special case for 'input_encoding'
	    if ($optionname =~ m/^input_encoding$/i) {
		my $e = $encodings::encodings;
		foreach $enc (sort {$e->{$a}->{'name'} cmp $e->{$b}->{'name'}} keys (%$e)) {
		    print STDERR "        <Value>\n";
		    print STDERR "          <Name>$enc</Name>\n";
		    print STDERR "          <Desc>$e->{$enc}->{'name'}</Desc>\n";
		    print STDERR "        </Value>\n";
		}
	    }

	    print STDERR "      </List>\n";
	}

	# Show the default value for the option, if there is one
	if (defined $option->{'deft'}) {
	    print STDERR "      <Default>$option->{'deft'}</Default>\n";
	}

	print STDERR "    </Option>\n";
    }
}


sub find_longest_option_string
{
    local $options = shift(@_);

    local $maxlength = 0;
    foreach $option (@$options) {
	local $optionname = $option->{'name'};
	local $optiontype = $option->{'type'};

	local $optionlength = length("  -$optionname");
	if ($optiontype ne "flag") {
	    $optionlength = $optionlength + length(" <$optiontype>");
	}

	# Remember the longest
	if ($optionlength > $maxlength) {
	    $maxlength = $optionlength;
	}
    }
    return $maxlength;
}


sub print_options_txt
{
    local $options = shift(@_);
    local $optiondescoffset = shift(@_);

    foreach $option (@$options) {
	# Display option name
	local $optionname = $option->{'name'};
	print STDERR "  -$optionname";
	local $optionstringlength = length("  -$optionname");

	# Display option type, if the option is not a flag
	local $optiontype = $option->{'type'};
	if ($optiontype ne "flag") {
	    print STDERR " <$optiontype>";
	    $optionstringlength = $optionstringlength + length(" <$optiontype>");
	}

	# Display the option description
	local $optiondesc = $option->{'desc'};
	local $optionreqd = $option->{'reqd'};
	if (defined($optionreqd) && $optionreqd eq "yes") {
	    $optiondesc = "(REQUIRED) " . $optiondesc;
	}
	&display_text_in_column($optiondesc, $optiondescoffset, $optionstringlength, 80);

	# Show the default value for the option, if there is one
	local $optiondefault = $option->{'deft'};
	if (defined($optiondefault)) {
	    print STDERR " " x $optiondescoffset;
	    print STDERR "Default: " . $optiondefault . "\n";
	}

	# If the option has a list of possible values, display these
	local $optionvalueslist = $option->{'list'};
	if (defined($optionvalueslist)) {
	    print STDERR "\n";
	    foreach $optionvalue (@$optionvalueslist) {
		local $optionvaluename = $optionvalue->{'name'};
		print STDERR " " x $optiondescoffset;
		print STDERR "$optionvaluename:";

		local $optionvaluedesc = $optionvalue->{'desc'};
		&display_text_in_column($optionvaluedesc, $optiondescoffset + 2,
					$optiondescoffset + length($optionvaluename), 80);
	    }
	}

	# Special case for 'input_encoding'
	if ($optionname =~ m/^input_encoding$/i) {
	    my $e = $encodings::encodings;
	    foreach $enc (sort {$e->{$a}->{'name'} cmp $e->{$b}->{'name'}} keys (%$e)) {
		print STDERR " " x $optiondescoffset;
		print STDERR "$enc:";

		local $encodingdesc = $e->{$enc}->{'name'};
		&display_text_in_column($encodingdesc, $optiondescoffset + 2,
					$optiondescoffset + length("$enc:"), 80);
	    }
	}

	# Add a blank line to separate options
	print STDERR "\n";
    }
}


sub display_text_in_column
{
    local ($text, $columnbeg, $firstlineoffset, $columnend) = @_;

    # Spaces are put *before* words, so treat the column beginning as 1 smaller than it is
    $columnbeg = $columnbeg - 1;

    # Add some padding (if needed) for the first line
    local $linelength = $columnbeg;
    if ($firstlineoffset < $columnbeg) {
	print STDERR " " x ($columnbeg - $firstlineoffset);
    }
    else {
	$linelength = $firstlineoffset;
    }

    # Break the text into words, and display one at a time
    local @words = split(/ /, $text);

    foreach $word (@words) {
	# Unescape '<' and '>' characters
	$word =~ s/&lt;/</g;
	$word =~ s/&gt;/>/g;

	# If printing this word would exceed the column end, start a new line
	if (($linelength + length($word)) >= $columnend) {
	    print STDERR "\n";
	    print STDERR " " x $columnbeg;
	    $linelength = $columnbeg;
	}

	# Write the word
	print STDERR " $word";
	$linelength = $linelength + length(" $word");
    }

    print STDERR "\n";
}


1;