#!/usr/bin/perl -w

# Modules.
use strict;
use English;
use Pod::Usage;
use Getopt::Long;
use IO::File;

# YEAST byte codes.
my $code2class = {
    U => { code => 'U', type => 'bom',   title => "Byte order mark" },
    T => { code => 'T', type => 'text',  title => "Content text" },
    t => { code => 't', type => 'text',  title => "Non-content text" },
    B => { code => 'B', type => 'line',  title => "Content line break" },
    b => { code => 'b', type => 'line',  title => "Non-content line break" },
    L => { code => 'L', type => 'line',  title => "Line break normalized to line feed" },
    l => { code => 'l', type => 'line',  title => "Line break folded to space" },
    I => { code => 'I', type => 'text',  title => "Indicator character" },
    w => { code => 'w', type => 'text',  title => "Non-content white space" },
    i => { code => 'i', type => 'text',  title => "Indentation white space" },
    K => { code => 'K', type => 'text',  title => "Document start marker" },
    k => { code => 'k', type => 'text',  title => "Document end marker" },
    E => { code => 'E', type => 'begin', title => "Escape sequence" },
    e => { code => 'e', type => 'end',   title => "Escape sequence" },
    C => { code => 'C', type => 'begin', title => "Comment" },
    c => { code => 'c', type => 'end',   title => "Comment" },
    D => { code => 'D', type => 'begin', title => "Directive" },
    d => { code => 'd', type => 'end',   title => "Directive" },
    G => { code => 'G', type => 'begin', title => "Tag" },
    g => { code => 'g', type => 'end',   title => "Tag" },
    H => { code => 'H', type => 'begin', title => "Handle" },
    h => { code => 'h', type => 'end',   title => "Handle" },
    A => { code => 'A', type => 'begin', title => "Anchor" },
    a => { code => 'a', type => 'end',   title => "Anchor" },
    P => { code => 'P', type => 'begin', title => "Properties" },
    p => { code => 'p', type => 'end',   title => "Properties" },
    R => { code => 'R', type => 'begin', title => "Alias" },
    r => { code => 'r', type => 'end',   title => "Alias" },
    S => { code => 'S', type => 'begin', title => "Scalar" },
    s => { code => 's', type => 'end',   title => "Scalar" },
    Q => { code => 'Q', type => 'begin', title => "Sequence" },
    q => { code => 'q', type => 'end',   title => "Sequence" },
    M => { code => 'M', type => 'begin', title => "Mapping" },
    m => { code => 'm', type => 'end',   title => "Mapping" },
    N => { code => 'N', type => 'begin', title => "Node" },
    n => { code => 'n', type => 'end',   title => "Node" },
    X => { code => 'X', type => 'begin', title => "Key:value pair" },
    x => { code => 'x', type => 'end',   title => "Key:value pair" },
    O => { code => 'O', type => 'begin', title => "Document" },
    o => { code => 'o', type => 'end',   title => "Document" },
    Y => { code => 'Y', type => 'begin', title => "Stream" },
    y => { code => 'y', type => 'end',   title => "Stream" }
};

# Command line arguments.
my $output_file = '';
my $css_file = '';
my $link_css = '';
my $output = *STDOUT{IO};
my $tree_title = 'Syntax Tree';
my $text_title = 'YAML Text';

# Loaded byte codes.
my $data = [];

# Tree printing.
my $next_id;

# Main program.
parse_argv();
load_input();
print_output();

# Functions.

sub parse_argv {
    my $do_help = "";
    my $do_man = "";
    GetOptions("help|h" => \$do_help,
               "man|m" => \$do_man,
               "output|o=s" => \$output_file,
               "css|c=s" => \$css_file,
               "tree-title|r=s" => \$tree_title,
               "text-title|x=s" => \$text_title,
               "link-css|l" => \$link_css)
        || pod2usage(-verbose => 0);
    pod2usage(-verbose => 1) if $do_help;
    pod2usage(-verbose => 2) if $do_man;
    die("Only one input file, please\n") if @ARGV > 1;
    die("No CSS file specified to link to\n") if $link_css && !$css_file;
    if ($output_file) {
        open ($output, ">$output_file") || die("open(>$output_file): $!");
    }
}

sub load_input {
    my $stack = [];
    my $num = 0;
    while (my $line = <>) {
        $num++;
        chomp($line);
        die("Line $num is not a byte code line\n")
            unless $line =~ /^(.)(.*)$/;
        my $code = $1;
        my $text = $2;
        my $class = $code2class->{$code};
        die("Line $num contains unknown code \"$code\"\n")
            unless $class;
        die("Oops!") unless $class->{code} eq $code;
        if ($class->{type} eq 'bom') {
            $text = "$code$text";
        } else {
            $text =~ s:\\x0[dD]:&crarr;:g;
            $text =~ s:\\x0[aA]:&darr;:g;
            $text =~ s:\\x85:&dArr;:g;
            $text =~ s:\\u2028:&sect;:g;
            $text =~ s:\\u2029:&para;:g;
            $text =~ s:\t:&rarr;:g;
            $text =~ s: :&middot;:g;
            $text =~ s:\\u202F:&diams;:g;
        }
        if ($class->{type} eq 'begin') {
            push(@$stack, [$num, $class]);
        } elsif ($class->{type} eq 'end') {
            my $title = $class->{title};
            my ($begin_num, $begin_class) = @{pop(@$stack)};
            my $begin_code = $begin_class->{code};
            my $begin_title = $begin_class->{title};
            die("Line $num ($code/$title) "
              . "ends line $begin_num ($begin_code/$begin_title)\n")
                if $title ne $begin_title;
        }
        push(@$data, [$class, $text]);
    }
    die("Unterminated groups\n") if @$stack;
}

sub print_output {
    print $output <<"EOF";
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE html PUBLIC
 "-//W3C//DTD XHTML 1.0 Transitional//EN"
 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>YEAST2HTML</title>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" />
<meta name="generator" content="yeast2html" />
EOF
    print_css();
    print_script();
    print $output <<"EOF";
</head>
<body>
EOF
    print_text();
    print_tree();
    print $output <<"EOF";
</body>
</html>
EOF
}

sub print_css {
    if ($link_css) {
        print $output "<link rel=\"stylesheet\" href=\"$css_file\" type=\"text/css\" />\n";
        return;
    }
    print $output "<style type=\"text/css\">\n";
    if ($css_file) {
        open(CSS, "$css_file") || die("open($css_file): $!\n");
        while (my $line = <CSS>) {
            print $output $line;
        }
        close(CSS) || die("close($css_file): $!\n");
    } else {
        print $output <<"EOF";
div.tree_div {
    position: absolute;
    left: 0%;
    top: 0%;
    width: 50%;
    height: 100%;
    overflow: scroll;
}
div.text_div {
    position: absolute;
    left: 50%;
    top: 0%;
    width: 50%;
    height: 100%;
    overflow: scroll;
}
span.highlight {
    background-color: yellow;
}
span.text {
    font-family: monospace;
}
EOF
    }
    print $output "</style>\n";
}

sub print_script {
    print $output <<"EOF";
<script language="JavaScript">
function toggle(id) {
    var nest_style = document.getElementById("tree_nest_" + id).style;
    var glyph = document.getElementById("tree_glyph_" + id);
    if (nest_style.display == "none") {
        nest_style.display = "block";
        glyph.innerHTML = "&mdash;";
    } else {
        nest_style.display = "none";
        glyph.innerHTML = "+";
    }
}
var highlighted = 0;
function highlight(id) {
    if (highlighted == 0) {
        var text = document.getElementById("text_" + id);
        var tree = document.getElementById("tree_text_" + id);
        text.className = "text highlight";
        tree.className = "tree_text highlight";
        highlighted = id;
    } else if (highlighted == id) {
        var text = document.getElementById("text_" + id);
        var tree = document.getElementById("tree_text_" + id);
        text.className = "text";
        tree.className = "tree_text";
        highlighted = 0;
        return;
    } else {
        var old_text = document.getElementById("text_" + highlighted);
        var old_tree = document.getElementById("tree_text_" + highlighted);
        var new_text = document.getElementById("text_" + id);
        var new_tree = document.getElementById("tree_text_" + id);
        old_text.className = "text";
        old_tree.className = "tree_text";
        new_text.className = "text highlight";
        new_tree.className = "tree_text highlight";
        highlighted = id;
    }
}
</script>
EOF
}

sub print_tree {
    print $output "<div id=\"tree_div\" class=\"tree_div\">\n";
    print $output "<h1 id=\"tree_title\" class=\"tree_title\">$tree_title</h1>";
    $next_id = 0;
    start_tree_node(0, "Legend");
    print_legend();
    end_tree_node();
    my $depth = 0;
    for my $entry (@$data) {
        my ($class, $text) = @$entry;
        if ($class->{type} eq 'begin') {
            start_tree_node($depth++, $class->{title});
        } elsif ($class->{type} eq 'end') {
            end_tree_node();
            $depth--;
        } else {
            my $label = $class->{title};
            $label .= " ($text)" if $class->{type} eq 'bom';
            tree_leaf($depth, $label);
        }
    }
    print $output "</div>\n";
}

sub start_tree_node {
    my $depth = shift;
    my $text = shift;
    print $output "<div id=\"tree_line_$next_id\" class=\"tree_node parent_node\">\n";
    for (my $i = 1; $i <= $depth; $i++) {
        print $output "<span class=\"tree_space parent_node space_$i depth_$depth\">&nbsp;</span>"
    }
    print $output "<span id=\"tree_glyph_$next_id\" class=\"tree_glyph parent_node\" onclick=\"toggle($next_id)\">&mdash;</span>";
    print $output "<span id=\"tree_text_$next_id\" class=\"tree_text parent_node"
                . ($next_id > 0 ? "" : " legend_node")
                . "\" onclick=\"highlight($next_id)\">$text</span>\n";
    print $output "<div id=\"tree_nest_$next_id\" class=\"tree_nest\">\n";
    $next_id++;
}

sub end_tree_node {
    print $output "</div></div>\n";
}

sub tree_leaf {
    my $depth = shift;
    my $text = shift;
    print $output "<div id=\"tree_line_$next_id\" class=\"tree_node leaf_node\">\n";
    for (my $i = 1; $i <= $depth; $i++) {
        print $output "<span class=\"tree_space leaf_node space_$i depth_$depth\">&nbsp;</span>"
    }
    print $output "<span id=\"tree_glyph_$next_id\" class=\"tree_glyph leaf_node\">&middot;</span>";
    print $output "<span id=\"tree_text_$next_id\" class=\"tree_text leaf_node\" onclick=\"highlight($next_id)\">$text</span>\n";
    print $output "</div>\n";
    $next_id++;
}

sub print_legend {
    print <<"EOF";
<table id="legend_table" class="legend_table">
<tr>
<td class="legend_space">&nbsp;</td>
<td class="legend_glyph">&crarr;</td>
<td class="legend_text">Carriage Return</td>
</tr>
<tr>
<td class="legend_space">&nbsp;</td>
<td class="legend_glyph">&darr;</td>
<td class="legend_text">Line Feed</td>
</tr>
<tr>
<td class="legend_space">&nbsp;</td>
<td class="legend_glyph">&dArr;</td>
<td class="legend_text">Next Line</td>
</tr>
<tr>
<td class="legend_space">&nbsp;</td>
<td class="legend_glyph">&sect;</td>
<td class="legend_text">Line separator</td>
</tr>
<tr>
<td class="legend_space">&nbsp;</td>
<td class="legend_glyph">&para;</td>
<td class="legend_text">Paragraph separator</td>
</tr>
<tr>
<td class="legend_space">&nbsp;</td>
<td class="legend_glyph">&rarr;</td>
<td class="legend_text">Tab</td>
</tr>
<tr>
<td class="legend_space">&nbsp;</td>
<td class="legend_glyph">&diams;</td>
<td class="legend_text">Non-breaking space</td>
</tr>
<tr>
<td class="legend_space">&nbsp;</td>
<td class="legend_glyph">&middot;</td>
<td class="legend_text">Space</td>
</tr>
<tr>
<td class="legend_space">&nbsp;</td>
<td class="legend_glyph">&deg;</td>
<td class="legend_text">Empty</td>
</tr>
<tr>
<td class="legend_space">&nbsp;</td>
<td class="legend_glyph">&hArr;</td>
<td class="legend_text">Byte order mark</td>
</tr>
</table>
EOF
}

sub print_text {
    print $output "<div id=\"text_div\" class=\"text_div\">\n";
    print $output "<h1 id=\"text_title\" class=\"text_title\">$text_title</h1>";
    $next_id = 1;
    my $pending_break = 0;
    for my $entry (@$data) {
        my ($class, $text) = @$entry;
        if ($class->{type} eq 'end') {
            print $output "</span>";
            next;
        }
        if ($pending_break) {
            print $output "<br/>\n";
            $pending_break = 0;
        }
        print $output "<span id=\"text_$next_id\" class=\"text\"";
        print " onclick=\"highlight($next_id)\"" unless $class->{type} eq 'begin';
        print ">";
        $next_id++;
        next if $class->{type} eq 'begin';
        if ($class->{type} eq 'bom') {
            print $output "&hArr;</span>";
        } else {
            print $output "$text</span>";
        }
        $pending_break = $class->{type} eq 'line';
    }
    print $output "\n</div>\n";
}

__END__

=head1 NAME

yeast2html - Convert YEAST byte codes to viewable HTML

=head1 SYNOPSIS

yeast2html [options] [yeast-file]

=head1 DESCRIPTION

This Perl script is designed to allow exploring the syntactical structure of
YAML files in an interactive way. The input file is a sequence of YEAST byte
codes that describe the YAML text. The output is an XHTML file that allows
viewing the YAML syntax tree together with the original (reconstructed) YAML
text.

=head1 COMMAND LINE OPTIONS

=over 4

=item B<--output|-o> I<output-file>

Redirect the output XHTML to the specified I<output-file>. By default the XHTML
is written to standard output.

=item B<--css|-c> I<css-file>

Use the specified I<css-file> to control the style of the generated XHTML. By
default, a minimal set of CSS rules is used, which doesn't look very pretty.

=item B<--link-css|-l>

By default, the content of the I<css-file> is embedded in the header of the
generated XHTML. If this flag is given, this is replaced by a link to the
I<css-file>. Note that in this case the I<css-file> path must be relative to
the URL used for the XHTML file.

=item B<--tree-title|-r> I<title>

The title for the tree part of the display. By default, it says "Syntax Tree".

=item B<--text-title|-x> I<title>

The title for the text part of the display. By default, it says "YAML Text".

=item B<--help|-h>

Print short usage message and exit.

=item B<--man|-m>

Print this man page and exit.

=back

=head1 SEE ALSO

L<yaml2yeast>

=head1 AUTHOR

Oren Ben-Kiki <oren@ben-kiki.org>

=head1 COPYRIGHT

Copyright (c) 2007, Oren Ben-Kiki

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free
Software Foundation; either version 2.1 of the License, or (at your option) any
later version.

This library 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 Lesser General Public License for more
details.

You should have received a copy of the GNU Lesser General Public License along
with this library; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA