use strict;
use 5.005;
use Pod::Tree;
use Pod::Tree::HTML;
use Pod::Tree::PerlUtil;

package Pod::Tree::PerlFunc;

use base qw(Pod::Tree::PerlUtil);


sub new
{
    my %defaults = (bgcolor   => '#ffffff',
		    text      => '#000000');

    my($class, $perl_dir, $html_dir, $link_map, %options) = @_;
    my $options = { %defaults, %options, link_map => $link_map };

    my $perl_func = { perl_dir => $perl_dir,
		      html_dir => $html_dir,
		      pod_dir  => 'pod',
		      func_dir => 'func',
		      page     => 'perlfunc',
		      options  => $options  };

    bless $perl_func, $class
}


sub scan
{
    my $perl_func = shift;
       $perl_func->report1("scan");
    
    $perl_func->load_tree;
    $perl_func->scan_tree;
}


sub load_tree
{
    my $perl_func  = shift;
    my $perl_dir   = $perl_func->{perl_dir};
    my $pod_dir    = $perl_func->{pod_dir};
    my $page       = $perl_func->{page};
    my $source     = "$perl_dir/$pod_dir/$page.pod";
    my $win_source = "$perl_dir/lib/$pod_dir/$page.pod";

    my $tree = new Pod::Tree;
    $tree->load_file($source    ) or	# for building the doc set from a Perl distribution	
    $tree->load_file($win_source) or	# for building the doc set from a Windows installation
	die "Pod::Tree::PerlFunc::scan: Can't find $source or $win_source\n";

    my $node  = $tree->pop;
    my $funcs = $node->get_children;

    $perl_func->{tree } = $tree;
    $perl_func->{funcs} = $funcs;
}


sub scan_tree
{
    my $perl_func = shift;
    my $funcs = $perl_func->{funcs};
    my @funcs = @$funcs;

    my $link_map = $perl_func->{options}{link_map};

    while (@funcs)
    {
	my @items = Shift_Items(\@funcs);
	my($func0, $file0) = Parse_Name($items[0]);

	for my $item (@items)
	{
	    my($func, $file) = Parse_Name($item);
	    $perl_func->report2($func);
	    $perl_func->{index}{$func} = $file0;
	    $link_map->add_func($file, $file0);
	}
    }
}


sub index
{
    my $perl_func = shift;
       $perl_func->report1("index");

    $perl_func->add_links;
    $perl_func->add_index;

    my $tree     = $perl_func->{tree};
    my $html_dir = $perl_func->{html_dir};
    my $pod_dir  = $perl_func->{pod_dir};
    my $page     = $perl_func->{page};
    my $options  = $perl_func->{options};

       $perl_func->mkdir("$html_dir/$pod_dir/");
       $options->{link_map}->set_depth(1);

    my $dest = "$html_dir/$pod_dir/$page.html";
    my $html = new Pod::Tree::HTML $tree, $dest, %$options;
    $html->translate;
}


sub add_links
{
    my $perl_func = shift;
    my $tree      = $perl_func->{tree};

    $tree->walk(sub { $perl_func->_add_links(shift) } );
}


sub _add_links
{
    my($perl_func, $node) = @_;

    is_sequence $node        or return 1;
    $node->get_letter eq 'C' or return 1;
    
    my($func) = Parse_Name($node);
    my $file  = $perl_func->{index}{$func};
    $file or return 1;

    # :TRICKY: *replaces* the node in the tree
    my $page = $perl_func->{page};
    $_[1] = Pod::Tree::Node->link($node, $page, $file);

    0
}


sub add_index
{
    my $perl_func = shift;

    my %funcs;
    my $index = $perl_func->{index};
    for my $func (sort keys %$index)
    {
	my $file   = $index->{$func};
	my $letter = substr($func, 0, 1);
	push @{$funcs{$letter}}, [ $func, $file ];
    }

    my $page = $perl_func->{page};
    my @lines;
    for my $letter (sort keys %funcs)
    {
	my $funcs = $funcs{$letter};
	my @links = map { "L<C<$_->[0]>|$page/$_->[1]>" } @$funcs;
	my $line  = join ", ", @links;
	push @lines, $line;
    }

    my $pod = join "\n\n", @lines;

    my $index = new Pod::Tree;
    $index->load_string($pod);
    my $children = $index->get_root->get_children;

    $perl_func->{tree}->push(@$children);
}


sub translate
{
    my $perl_func = shift;
       $perl_func->report1("translate");

    my $html_dir  = $perl_func->{html_dir};
    my $pod_dir   = $perl_func->{pod_dir};
    my $func_dir  = $perl_func->{func_dir};
       $perl_func->mkdir("$html_dir/$pod_dir/$func_dir");

    my $perl_dir  = $perl_func->{perl_dir};
    my $funcs     = $perl_func->{funcs};
    my $options   = $perl_func->{options};
    my $link_map  = $options->{link_map};

       $link_map->set_depth(2);
       $link_map->force_func(1);
       $options ->{toc} = 0;

    while (@$funcs)
    {
	my @items = Shift_Items($funcs);
	my($func, $file) = Parse_Name($items[0]);
	$perl_func->report2("func/$file");

	my $tree  = new Pod::Tree;
	   $tree->load_string("=head1 $func\n\n=over 4\n\n=back");
	my $list = $tree->get_root->get_children->[1];
	   $list->set_children(\@items);
	   $list->_set_list_type;

	$options->{title} = $func;
	my $dest  = "$html_dir/$pod_dir/$func_dir/$file.html";
	my $html  = new Pod::Tree::HTML $tree, $dest, %$options;
	$html->translate;
    }

    $link_map->force_func(0);
}


sub Shift_Items
{
    my $funcs = shift;
    my @items;

    while (@$funcs)
    {
	my $item = shift @$funcs;
	push @items, $item;

	@$funcs or last;

	my($func0) = Parse_Name($item);
	my($func1) = Parse_Name($funcs->[0]);
	my $sibs0  = $item->get_siblings;
	$func0 eq $func1 or @$sibs0==0 or last;
    }

    @items
}


sub Parse_Name
{
    my $item  = shift;
    my $text  = $item->get_deep_text;
    my @words = split m([^\w\-]+), $text;

    my $func = $words[0];
    my $file = $func;
       $file =~ tr(A-Za-z0-9_-)()cd;

    ($func, $file)
}

1

__END__

=head1 NAME

Pod::Tree::PerlFunc - translate F<perlfunc.pod> to HTML

=head1 SYNOPSIS

  $perl_map  = new Pod::Tree::PerlMap;
  $perl_func = new Pod::Tree::PerlFunc $perl_dir, $HTML_dir, $perl_map, %opts;

  $perl_func->scan;
  $perl_func->index;
  $perl_func->translate;

=head1 DESCRIPTION

C<Pod::Tree::PerlFunc> translates F<perlfunc.pod> to HTML.
It creates a separate HTML page for each function description in
F<perlfunc.pod>. The pages for the individual descriptions are
named after the function and written to a F<func/> subdirectory.
F<perlfunc.html> is generated as an index to all the pages in 
F<func/>.

C<Pod::Tree::PerlFunc> generates and uses an index of the functions 
that it finds in F<perlfunc.pod> to construct HTML links.
Other modules can also use this index.

=head1 METHODS

=over 4

=item I<$perl_func> = C<new> C<Pod::Tree::PerlFunc> I<$perl_dir>,
I<$HTML_dir>, I<$perl_map>, I<%options>

Creates and returns a new C<Pod::Tree::PerlFunc> object.

I<$perl_dir> is the root of the Perl source tree.

I<$HTML_dir> is the directory where HTML files will be written.

I<$perl_map> maps function names to URLs.

I<%options> are passed through to C<Pod::Tree::HTML>.

=item I<$perl_func>->C<scan>

Reads F<perlfunc.pod> and identifies all the functions in it.
Each function that is identified is entered into I<$perl_map>.

=item I<$perl_func>->C<index>

Generates a top-level index of all the functions. 
The index is written to I<HTML_dir>C</pod/perlfunc.html>.

=item I<$perl_func>->C<translate>

Translates each function found by C<scan> to HTML.
The HTML pages are written to I<HTML_dir>C</pod/func/>.

=back

=head1 LINKING

C<Pod::Tree::PerlFunc> indexes every C<=item> paragraph in 
F<perlfunc.html>. To link, for example, to the C<abs> function, write

    L<func/abs>

=head1 REQUIRES

    5.005;
    Pod::Tree;
    Pod::Tree::HTML;
    Pod::Tree::PerlUtil;

=head1 EXPORTS

Nothing.

=head1 SEE ALSO

L<C<Pod::Tree::HTML>>, L<C<Pod::Tree::PerlMap>>, 

=head1 AUTHOR

Steven McDougall, swmcd@world.std.com

=head1 COPYRIGHT

Copyright (c) 2000 by Steven McDougall.  This module is free software;
you can redistribute it and/or modify it under the same terms as Perl itself.