#!/usr/bin/perl -w

use strict;

use XML::LibXML;
use IO::File;

# ------------------------------------------------------------------------- #
# (c) 2003 christian p. glahn
# ------------------------------------------------------------------------- #

# ------------------------------------------------------------------------- #
# This is an example how to use the DOM interface of XML::LibXML The
# script reads a XML File with a module specification. If the module
# contains several classes, the script fetches them and stores the
# data into different POD Files.
#
# Note this is just an example, to demonstrate how XML::LibXML works.
# The code works for the XML::LibXML documentation, but may not work
# for any other docbook file.
#
# If you are interested what the results are, check the README and the POD
# files shipped with XML::LibXML.
# ------------------------------------------------------------------------- #

# ------------------------------------------------------------------------- #
# SYNOPSIS:
# xmllibxmldocs.pl $dokbook_file $targetdir
#
my $srcfile   = shift @ARGV;
my $targetdir = shift @ARGV;

unless ( $targetdir =~ /\/$/ ) {
    $targetdir .= "/";
}

# ------------------------------------------------------------------------- #
#
# ------------------------------------------------------------------------- #
# init the parser
my $parser = XML::LibXML->new();
$parser->load_ext_dtd(0);
# ------------------------------------------------------------------------- #
#
# ------------------------------------------------------------------------- #
# load the document into memory.
my $doc = $parser->parse_file( $srcfile );
# ------------------------------------------------------------------------- #
#
# ------------------------------------------------------------------------- #
# good implementations would use XSLT to convert a docbook to anyother
# text format. Since the module does not presume libxslt installed, we
# have to do the dirty job.
my $ch = ChapterHandler->new($targetdir);

# ------------------------------------------------------------------------- #
# init the common parts in all pods
my ( $bookinfo ) = $doc->findnodes( "//bookinfo" );
$ch->set_general_info( $bookinfo );
# ------------------------------------------------------------------------- #

# ------------------------------------------------------------------------- #
# then process each chapter of the XML::LibXML book
my @chapters = $doc->findnodes( "//chapter" );
foreach my $chap ( @chapters ) {
    $ch->handle( $chap );
}
# ------------------------------------------------------------------------- #
# ------------------------------------------------------------------------- #

# ------------------------------------------------------------------------- #
# the class to process our dokbook file
# ------------------------------------------------------------------------- #
package ChapterHandler;

# ------------------------------------------------------------------------- #
# the constructor
# ------------------------------------------------------------------------- #
sub new{
    my $class = shift;
    my $dir   = shift;
    my $self = bless {directory => $dir}, $class;

    return $self;
}
# ------------------------------------------------------------------------- #

# ------------------------------------------------------------------------- #
# set_general_info
# ------------------------------------------------------------------------- #
# processes the bookinfo tag of XML::LibXML to extract common information such
# as version or copyright information
sub set_general_info {
    my $self = shift;
    my $infonode = shift;
    return unless defined $infonode;

    my $infostr = "=head1 AUTHORS\n\n";
    my @authors = $infonode->findnodes( "authorgroup/author" );
    foreach my $author ( @authors ) {
        my ( $node_fn ) = $author->getChildrenByTagName( "firstname" );
        my ( $node_sn ) = $author->getChildrenByTagName( "surname" );
        if ( defined $node_fn ) {
            $infostr .= $node_fn->string_value();
        }
        if ( defined $node_sn ) {
            $infostr .= " ". $node_sn->string_value();
        }
        if ( defined $author->nextSibling() ) {
            $infostr .= ", \n";
        }
        else {
            $infostr .= "\n\n";
        }
    }

    my ( $version ) = $infonode->findnodes( "edition" );
    if ( defined $version ) {
        $infostr .= "=head1 VERSION\n\n" . $version->string_value() . "\n\n";
    }

    my ( $copyright ) = $infonode->findnodes( "copyright" );
    if ( defined $copyright ) {
        $infostr .= "=head1 COPYRIGHT\n\n";
        my $node_y = $copyright->getChildrenByTagName( "year" );
        my $node_h = $copyright->getChildrenByTagName( "holder" );
        if ( defined $node_y ) {
            $infostr .= $node_y->string_value() . ", ";
        }
        if ( defined $node_h ) {
            $infostr .= $node_h->string_value();
        }
        $infostr .= ", All rights reserved.\n\n=cut\n"
    }

    $self->{infoblock} = $infostr;
}

# ------------------------------------------------------------------------- #
# handle
# ------------------------------------------------------------------------- #
# This function opens the output file and decides how the chapter is
# processed
sub handle {
    my $self = shift;
    my $chapter = shift;

    my ( $abbr ) = $chapter->findnodes( "titleabbrev" );
    if ( defined $abbr ) {
        # create a new file.
        my $filename = $abbr->string_value();
        $filename =~ s/^\s*|\s*$//g;
        my $dir = $self->{directory};

        $filename =~ s/XML\:\:LibXML//g;
        $filename =~ s/^-|^\:\://g;   # remove the first colon or minus. 
        $filename =~ s/\:\:/\//g;     # transform remaining colons to paths.
        # the previous statement should work for existing modules. This could be
        # dangerous for nested modules, which do not exist at the time of writing
        # this code.

	unless ( length $filename ) {
            $dir = "";
            $filename = "LibXML";
        }

        if ( $filename ne "README" and $filename ne "LICENSE" ) {
            $filename .= ".pod";
        }
        else {
            $dir = "";
        }

        $self->{OFILE} = IO::File->new();
        $self->{OFILE}->open(">".$dir.$filename);

        if ( $abbr->string_value() eq "README"
             or $abbr->string_value() eq "LICENSE" ) {

            # Text only chapters in the documentation
            $self->dump_text( $chapter );
        }
        else {
            # print header
            # print synopsis
            # process the information itself
            # dump the info block
            $self->dump_pod( $chapter );
            $self->{OFILE}->print( $self->{infoblock} );
        }
        # close the file
        $self->{OFILE}->close();
    }
}

# ------------------------------------------------------------------------- #
# dump_text
# ------------------------------------------------------------------------- #
# convert the chapter into a textfile, such as README.
sub dump_text {
    my $self = shift;
    my $chap = shift;

    if ( $chap->nodeName() eq "chapter" ) {
        my ( $title ) = $chap->getChildrenByTagName( "title" );
        my $str =  $title->string_value();
        my $len = length $str;
        $self->{OFILE}->print( uc($str) . "\n" );
        $self->{OFILE}->print( "=" x $len );
        $self->{OFILE}->print( "\n\n" );
    }

    foreach my $node ( $chap->childNodes() ) {
        if ( $node->nodeName() eq "para" ) {
            # we split at the last whitespace before 80 chars
            my $string = $node->string_value();
            $string =~ s/^\s*|\s*$//g;

            my $os = "";
            my @words = split /\s+/, $string;
            foreach my $word ( @words ) {
                if ( (length( $os ) + length( $word ) + 1) < 80 ) {
                    if ( length $os ) { $os .= " "; }
                    $os .= $word;
                }
                else {
                    $self->{OFILE}->print( $os . "\n" );
                    $os = $word;
                }
            }
            $self->{OFILE}->print( $os );
            $self->{OFILE}->print( "\n\n" );
        }
        elsif ( $node->nodeName() eq "sect1" ) {
            my ( $title ) = $node->getChildrenByTagName( "title" );
            my $str = $title->string_value();
            my $len = length $str;

            $self->{OFILE}->print( "\n" . uc($str) . "\n" ); 
            $self->{OFILE}->print( "=" x $len );
            $self->{OFILE}->print( "\n\n" );
            $self->dump_text( $node );
        }
        elsif (  $node->nodeName() eq "sect2" ) {
            my ( $title ) = $node->getChildrenByTagName( "title" );
            my $str = $title->string_value();
            my $len = length $str;

            $self->{OFILE}->print( "\n" . $str . "\n" );
            $self->{OFILE}->print( "=" x $len );
            $self->{OFILE}->print( "\n\n" );
            $self->dump_text( $node );
        }
        elsif ( $node->nodeName() eq "itemizedlist" ) {
            my @items = $node->findnodes( "listitem" );
            my $sp= "  ";
            foreach my $item ( @items ) {
                $self->{OFILE}->print( "$sp o " );
                my $str = $item->string_value();
                $str =~ s/^\s*|\s*$//g;
                $self->{OFILE}->print( $str );
                $self->{OFILE}->print( "\n" );
            }
            $self->{OFILE}->print( "\n" );
        }
        elsif ( $node->nodeName() eq "orderedlist" ) {
            my @items = $node->findnodes( "listitem" );
            my $i = 0;
            my $sp= "  ";
            foreach my $item ( @items ) {
                $i++;
                $self->{OFILE}->print( "$sp $i " );
                my $str = $item->string_value();
                $str =~ s/^\s*|\s*$//g;
                $self->{OFILE}->print( $str );
                $self->{OFILE}->print( "\n" );
            }
            $self->{OFILE}->print( "\n" );
        }
        elsif ( $node->nodeName() eq "programlisting" ) {
            my $str = $node->string_value();
            $str =~ s/\n/\n> /g;
            $self->{OFILE}->print( "> ". $str );
            $self->{OFILE}->print( "\n\n" );
        }
    }
}

# ------------------------------------------------------------------------- #
# dump_pod
# ------------------------------------------------------------------------- #
# This method is used to create the real POD files for XML::LibXML. It is not
# too sophisticated, but it already does quite a good job.
sub dump_pod {
    my $self = shift;
    my $chap = shift;

    if ( $chap->nodeName() eq "chapter" ) {
        my ( $title ) = $chap->getChildrenByTagName( "title" );
        my ( $ttlabbr ) = $chap->getChildrenByTagName( "titleabbrev" );
        my $str =  $ttlabbr->string_value() . " - ".$title->string_value();
        $self->{OFILE}->print(  "=head1 NAME\n\n$str\n\n" );
        my @funcs = $chap->findnodes( ".//funcsynopsis" );
        if ( scalar @funcs ) {
            $self->{OFILE}->print( "=head1 SYNOPSIS\n\n" );
            foreach my $s ( @funcs ) {
                $self->dump_pod( $s );
            }
            $self->{OFILE}->print( "\n\n=head1 DESCRIPTION\n\n" );
        }
    }

    foreach my $node ( $chap->childNodes() ) {
        if ( $node->nodeName() eq "para" ) {
            # we split at the last whitespace before 80 chars
            my $string = $node->string_value();
            $string =~ s/^\s*|\s*$//g;

            my $os = "";
            my @words = split /\s+/, $string;
            foreach my $word ( @words ) {
                if ( (length( $os ) + length( $word ) + 1) < 80 ) {
                    if ( length $os ) { $os .= " "; }
                    $os .= $word;
                }
                else {
                    $self->{OFILE}->print( $os . "\n" );
                    $os = $word;
                }
            }
            $self->{OFILE}->print( $os );
            $self->{OFILE}->print( "\n\n" );
        }
        elsif ( $node->nodeName() eq "sect1" ) {
            my ( $title ) = $node->getChildrenByTagName( "title" );
            my $str = $title->string_value();

            $self->{OFILE}->print( "\n=head1 " . uc($str) );
            $self->{OFILE}->print( "\n\n" );
            $self->dump_pod( $node );
        }
        elsif (  $node->nodeName() eq "sect2" ) {
            my ( $title ) = $node->getChildrenByTagName( "title" );
            my $str = $title->string_value();
            my $len = length $str;

            $self->{OFILE}->print( "\n=head2 " . $str . "\n\n" );

            $self->dump_pod( $node );
        }
        elsif ( $node->nodeName() eq "itemizedlist" ) {
            my @items = $node->findnodes( "listitem" );
            my $sp= "  ";
            $self->{OFILE}->print( "\n=over 4\n\n" );
            foreach my $item ( @items ) {
                my $str = $item->string_value();
                $str =~ s/^\s*|\s*$//g;
                $self->{OFILE}->print( "=item * ".$str );
                $self->{OFILE}->print( "\n\n" );
            }
            $self->{OFILE}->print( "=back\n\n" );
        }
        elsif ( $node->nodeName() eq "orderedlist" ) {
            my @items = $node->findnodes( "listitem" );
            my $i = 0;
            my $sp= "  ";

            $self->{OFILE}->print( "=over 4\n\n" );

            foreach my $item ( @items ) {
                $i++;
                $self->{OFILE}->print( "=item $i " );
                my $str = $item->string_value();
                $str =~ s/^\s*|\s*$//g;
                $self->{OFILE}->print( $str );
                $self->{OFILE}->print( "\n\n" );
            }
            $self->{OFILE}->print( "=back\n\n" );
        }
        elsif ( $node->nodeName() eq "variablelist" ) {
            $self->{OFILE}->print( "=over 4\n\n" );
            my @nodes = $node->findnodes( "varlistentry" );
            $self->dump_pod( $node );
            $self->{OFILE}->print( "\n=back\n\n" );
        }
        elsif ( $node->nodeName() eq "varlistentry" ) {
            my ( $term ) = $node->findnodes( "term" );
            $self->{OFILE}->print( "=item " );
            if ( defined $term ) {
                $self->{OFILE}->print( "B<".$term->string_value().">" );
            }
            $self->{OFILE}->print( "\n\n" );
            my @nodes =$node->findnodes( "listitem" );
            foreach my $it ( @nodes ) {
                $self->dump_pod( $it );
            }
            $self->{OFILE}->print( "\n" );
        }
        elsif ( $node->nodeName() eq "programlisting" ) {
            my $str = $node->string_value();
            $str =~ s/\n/\n  /g;
            $self->{OFILE}->print( "  ". $str );
            $self->{OFILE}->print( "\n\n" );
        }
        elsif ( $node->nodeName() eq "funcsynopsis" ) {
            $self->dump_pod($node);
            $self->{OFILE}->print( "\n" );
        }
        elsif(  $node->nodeName() eq "funcsynopsisinfo" ) {
            my $str = $node->string_value() ;
            $str =~ s/\n/\n  /g;
            $self->{OFILE}->print( "  $str\n" );

        }
    }
}

1;