#!./perl -Ilib -w

# This file should really be extracted from a .PL file

use strict;
use Config;		# for config options in the makefile
use File::Path qw(remove_tree);
use File::Spec::Functions qw(rel2abs no_upwards);
use Getopt::Long;	# for command-line parsing
use Cwd;
use Pod::Html 1.23 qw(anchorify relativize_url);

=head1 NAME

installhtml - converts a collection of POD pages to HTML format.

=head1 SYNOPSIS

  installhtml  [--help] [--podpath=<name>:...:<name>] [--podroot=<name>]
       [--htmldir=<name>] [--htmlroot=<name>]  [--norecurse] [--recurse]
       [--splithead=<name>,...,<name>]   [--splititem=<name>,...,<name>]
       [--ignore=<name>,...,<name>]  [--verbose]

=head1 DESCRIPTION

I<installhtml> converts a collection of POD pages to a corresponding
collection of HTML pages.  This is used to convert the pod pages found in the
perl distribution.  (It is not intended as a general-purpose
converter/installer of POD pages in HTML format.  See L<Pod::Html>.)

=head1 OPTIONS

=over 4

=item B<--help> help

Displays the usage.

=item B<--podroot> POD search path base directory

The base directory to search for all .pod and .pm files to be converted.
Default is current directory.

=item B<--podpath> POD search path

The list of directories to search for .pod and .pm files to be converted.
Default is 'podroot/.'.

=item B<--recurse> recurse on subdirectories

Whether or not to convert all .pm and .pod files found in subdirectories
too.  Default is to not recurse.

=item B<--htmldir> HTML destination directory

The base directory which all HTML files will be written to.  This should
be a path relative to the filesystem, not the resulting URL.

=item B<--htmlroot> URL base directory

The base directory which all resulting HTML files will be visible at in
a URL.  The default is '/'.

=item B<--splithead> POD files to split on =head directive

Comma-separated list of pod files to split by the =head directive.  The
.pod suffix is optional. These files should have names specified
relative to podroot.

=item B<--splititem> POD files to split on =item directive

Comma-separated list of all pod files to split by the =item directive.  The
.pod suffix is optional.  I<installhtml> does not do the actual split, rather
it invokes I<splitpod>, a separate program in the Perl 5 core distribution,
to do the dirty work.  As with --splithead, these files should have names
specified relative to podroot.

=item B<--splitpod> Directory containing the splitpod program

The directory containing the splitpod program. The default is 'podroot/pod'.

=item B<--ignore> files to be ignored

Comma-separated of files that shouldn't be installed, given relative
to podroot.

=item B<--verbose> verbose output

Self-explanatory.

=back

=head1 EXAMPLE

The following command-line is an example of the one we use to convert
perl documentation:

    ./installhtml --podpath=lib:ext:pod:vms   \
			--podroot=/usr/src/perl     \
			--htmldir=/perl/nmanual     \
			--htmlroot=/perl/nmanual    \
			--splithead=pod/perlipc     \
			--splititem=pod/perlfunc    \
			--recurse \
			--verbose

=head1 AUTHOR

Chris Hall E<lt>hallc@cs.colorado.eduE<gt>

=cut

my $usage;

$usage =<<END_OF_USAGE;
Usage: $0 --help --podpath=<name>:...:<name> --podroot=<name>
         --htmldir=<name> --htmlroot=<name> --norecurse --recurse
         --splithead=<name>,...,<name> --splititem=<name>,...,<name>
         --ignore=<name>,...,<name> --verbose

    --help      - this message
    --podpath   - colon-separated list of directories containing .pod and
                  .pm files to be converted (. by default).
    --podroot   - filesystem base directory from which all relative paths in
                  podpath stem (default is .).
    --htmldir   - directory to store resulting html files in relative
                  to the filesystem (\$podroot/html by default).
    --htmlroot  - http-server base directory from which all relative paths
                  in podpath stem (default is /).
    --norecurse - don't recurse on those subdirectories listed in podpath.
                  (default behavior).
    --recurse   - recurse on those subdirectories listed in podpath
    --splithead - comma-separated list of .pod or .pm files to split.  will
                  split each file into several smaller files at every occurrence
                  of a pod =head[1-6] directive.
    --splititem - comma-separated list of .pod or .pm files to split using
                  splitpod.
    --splitpod  - directory where the program splitpod can be found
                  (\$podroot/pod by default).
    --ignore    - comma-separated list of files that shouldn't be installed.
    --verbose   - self-explanatory.

END_OF_USAGE

my (@podpath, $podroot, $htmldir, $htmlroot, $recurse, @splithead,
    @splititem, $splitpod, $verbose, $pod2html, @ignore);

@podpath = ( "." );	# colon-separated list of directories containing .pod
			# and .pm files to be converted.
$podroot = ".";		# assume the pods we want are here
$htmldir = "";		# nothing for now...
$htmlroot = "/";	# default value
$recurse = 0;		# default behavior
@splithead = ();	# don't split any files by default
@splititem = ();	# don't split any files by default
$splitpod = "";		# nothing for now.

$verbose = 0;		# whether or not to print debugging info

$pod2html = "pod/pod2html";

usage("") unless @ARGV;

# Overcome shell's p1,..,p8 limitation.  
# See vms/descrip_mms.template -> descrip.mms for invocation.
if ( $^O eq 'VMS' ) { @ARGV = split(/\s+/,$ARGV[0]); }

our %Options;

# parse the command-line
my $result = GetOptions( \%Options, qw(
	help
	podpath=s
	podroot=s
	htmldir=s
	htmlroot=s
	ignore=s
	recurse!
	splithead=s
	splititem=s
	splitpod=s
	verbose
));
usage("invalid parameters") unless $result;
parse_command_line();


# set these variables to appropriate values if the user didn't specify
#  values for them.
$htmldir = "$htmlroot/html" unless $htmldir;
$splitpod = "$podroot/pod" unless $splitpod;


# make sure that the destination directory exists
(mkdir($htmldir, 0755) ||
	die "$0: cannot make directory $htmldir: $!\n") if ! -d $htmldir;


# the following array will eventually contain files that are to be
# ignored in the conversion process.  these are files that have been
# process by splititem or splithead and should not be converted as a
# result.
my @splitdirs;

# split pods. It's important to do this before convert ANY pods because
# it may affect some of the links
@splitdirs = ();    # files in these directories won't get an index
split_on_head($podroot, $htmldir, \@splitdirs, \@ignore, @splithead);
split_on_item($podroot,           \@splitdirs, \@ignore, @splititem);


# convert the pod pages found in @poddirs
#warn "converting files\n" if $verbose;
#warn "\@ignore\t= @ignore\n" if $verbose;
foreach my $dir (@podpath) {
    installdir($dir, $recurse, $podroot, \@splitdirs, \@ignore);
}


# now go through and create master indices for each pod we split
foreach my $dir (@splititem) {
    print "creating index $htmldir/$dir.html\n" if $verbose;
    create_index("$htmldir/$dir.html", "$htmldir/$dir");
}

foreach my $dir (@splithead) {
    (my $pod = $dir) =~ s,^.*/,,;
    $dir .= ".pod" unless $dir =~ /(\.pod|\.pm)$/;
    # let pod2html create the file
    runpod2html($dir, 1);

    # now go through and truncate after the index
    $dir =~ /^(.*?)(\.pod|\.pm)?$/sm;
    my $file = "$htmldir/$1";
    print "creating index $file.html\n" if $verbose;

    # read in everything until what would have been the first =head
    # directive, patching the index as we go.
    open(H, '<', "$file.html") ||
	die "$0: error opening $file.html for input: $!\n";
    $/ = "";
    my @data = ();
    while (<H>) {
	last if m!<h1 id="NAME">NAME</h1>!;
	$_ =~ s{href="#(.*)">}{
	    my $url = "$file/@{[anchorify(qq($1))]}.html" ;
	    $url = relativize_url( $url, "$file.html" )
	    if ( ! defined $Options{htmlroot} || $Options{htmlroot} eq '' );
	    "href=\"$url\">" ;
	}egi;
	push @data, $_;
    }
    close(H);

    # now rewrite the file
    open(H, '>', "$file.html") ||
	die "$0: error opening $file.html for output: $!\n";
    print H @data, "</body>\n\n</html>\n\n\n";
    close(H);
}

remove_tree(@splitdirs, {safe=>1});

##############################################################################


sub usage {
    warn "$0: @_\n" if @_;
    die $usage;
}


sub parse_command_line {
    usage() if defined $Options{help};
    $Options{help} = ""; 	    	    # make -w shut up

    # list of directories
    @podpath   = split(":", $Options{podpath}) if defined $Options{podpath};

    # lists of files
    @splithead = split(",", $Options{splithead}) if defined $Options{splithead};
    @splititem = split(",", $Options{splititem}) if defined $Options{splititem};

    $htmldir  = $Options{htmldir}	    if defined $Options{htmldir};
    $htmlroot = $Options{htmlroot}	    if defined $Options{htmlroot};
    $podroot  = $Options{podroot}	    if defined $Options{podroot};
    $splitpod = $Options{splitpod}	    if defined $Options{splitpod};

    $recurse  = $Options{recurse}	    if defined $Options{recurse};
    $verbose  = $Options{verbose}	    if defined $Options{verbose};

    @ignore = map "$podroot/$_", split(",", $Options{ignore}) if defined $Options{ignore};
}


sub create_index {
    my($html, $dir) = @_;
    (my $pod = $dir) =~ s,^.*/,,;

    # get the list of .html files in this directory
    opendir(DIR, $dir) ||
	die "$0: error opening directory $dir for reading: $!\n";
    my @files = sort(grep(/\.html?$/, readdir(DIR)));
    closedir(DIR);

    open(HTML, '>', $html) ||
	die "$0: error opening $html for output: $!\n";

    # for each .html file in the directory, extract the index
    #	embedded in the file and throw it into the big index.
    print HTML "<DL COMPACT>\n";
    foreach my $file (@files) {

	my $filedata = do {
	    open(my $in, '<', "$dir/$file") ||
		die "$0: error opening $dir/$file for input: $!\n";
	    local $/ = undef;
	    <$in>;
	};

	# pull out the NAME section
	my($lcp1, $lcp2) =
	    ($filedata =~
		m#<h1 id="NAME">NAME</h1>\s*<p>\s*(\S+)\s+-\s+(\S.*?\S)</p>#);
	defined $lcp1 or die "$0: can't find NAME section in $dir/$file\n";

	my $url= "$dir/$file" ;
	if ( ! defined $Options{htmlroot} || $Options{htmlroot} eq '' ) {
	    $url = relativize_url( $url, $html ) ;
	}

	print HTML qq(<DT><A HREF="$url">);
	print HTML "$lcp1</A></DT><DD>$lcp2</DD>\n";
    }
    print HTML "</DL>\n";

    close(HTML);
}


sub split_on_head {
    my($podroot, $htmldir, $splitdirs, $ignore, @splithead) = @_;
    my($pod, $dirname, $filename);

    # split the files specified in @splithead on =head[1-6] pod directives
    print "splitting files by head.\n" if $verbose && $#splithead >= 0;
    foreach $pod (@splithead) {
	# figure out the directory name and filename
	$pod      =~ s,^([^/]*)$,/$1,;
	$pod      =~ m,(.*)/(.*?)(\.pod)?$,;
	$dirname  = $1;
	$filename = "$2.pod";

	# since we are splitting this file it shouldn't be converted.
	push(@$ignore, "$podroot/$dirname/$filename");

	# split the pod
	splitpod("$podroot/$dirname/$filename", "$podroot/$dirname", $htmldir,
	    $splitdirs);
    }
}


sub split_on_item {
    my($podroot, $splitdirs, $ignore, @splititem) = @_;
    my($pwd, $dirname, $filename);

    print "splitting files by item.\n" if $verbose && $#splititem >= 0;
    $pwd = getcwd();
    my $splitter = rel2abs("$splitpod/splitpod", $pwd);
    my $perl = rel2abs($^X, $pwd);
    foreach my $pod (@splititem) {
	# figure out the directory to split into
	$pod      =~ s,^([^/]*)$,/$1,;
	$pod      =~ m,(.*)/(.*?)(\.pod)?$,;
	$dirname  = "$1/$2";
	$filename = "$2.pod";

	# since we are splitting this file it shouldn't be converted.
	push(@$ignore, "$podroot/$dirname.pod");

	# split the pod
	push(@$splitdirs, "$podroot/$dirname");
	-d "$podroot/$dirname" and remove_tree("$podroot/$dirname", {safe=>1});
	mkdir("$podroot/$dirname", 0755) ||
		    die "$0: error creating directory $podroot/$dirname: $!\n";
	chdir("$podroot/$dirname") ||
	    die "$0: error changing to directory $podroot/$dirname: $!\n";
	die "$splitter not found. Use '-splitpod dir' option.\n"
	    unless -f $splitter;
	system($perl, $splitter, "../$filename") &&
	    warn "$0: error running '$splitter ../$filename'"
		 ." from $podroot/$dirname";
    }
    chdir($pwd);
}


#
# splitpod - splits a .pod file into several smaller .pod files
#  where a new file is started each time a =head[1-6] pod directive
#  is encountered in the input file.
#
sub splitpod {
    my($pod, $poddir, $htmldir, $splitdirs) = @_;
    my(@poddata, @filedata, @heads);
    my($file, $i, $j, $prevsec, $section, $nextsec);

    print "splitting $pod\n" if $verbose;

    # read the file in paragraphs
    $/ = "";
    open(SPLITIN, '<', $pod) ||
	die "$0: error opening $pod for input: $!\n";
    @filedata = <SPLITIN>;
    close(SPLITIN) ||
	die "$0: error closing $pod: $!\n";

    # restore the file internally by =head[1-6] sections
    @poddata = ();
    for ($i = 0, $j = -1; $i <= $#filedata; $i++) {
	$j++ if ($filedata[$i] =~ /^\s*=head[1-6]/);
	if ($j >= 0) { 
	    $poddata[$j]  = "" unless defined $poddata[$j];
	    $poddata[$j] .= "\n$filedata[$i]" if $j >= 0;
	}
    }

    # create list of =head[1-6] sections so that we can rewrite
    #  L<> links as necessary.
    my %heads = ();
    foreach $i (0..$#poddata) {
	$heads{anchorify($1)} = 1 if $poddata[$i] =~ /=head[1-6]\s+(.*)/;
    }

    # create a directory of a similar name and store all the
    #  files in there
    $pod =~ s,.*/(.*),$1,;	# get the last part of the name
    my $dir = $pod;
    $dir =~ s/\.pod//g;
    push(@$splitdirs, "$poddir/$dir");
    -d "$poddir/$dir" and remove_tree("$poddir/$dir", {safe=>1});
    mkdir("$poddir/$dir", 0755) ||
	die "$0: could not create directory $poddir/$dir: $!\n";

    $poddata[0] =~ /^\s*=head[1-6]\s+(.*)/;
    $section    = "";
    $nextsec    = $1;

    # for each section of the file create a separate pod file
    for ($i = 0; $i <= $#poddata; $i++) {
	# determine the "prev" and "next" links
	$prevsec = $section;
	$section = $nextsec;
	if ($i < $#poddata) {
	    $poddata[$i+1] =~ /^\s*=head[1-6]\s+(.*)/;
	    $nextsec       = $1;
	} else {
	    $nextsec = "";
	}

	# determine an appropriate filename (this must correspond with
	#  what pod2html will try and guess)
	# $poddata[$i] =~ /^\s*=head[1-6]\s+(.*)/;
	$file = "$dir/" . anchorify($section) . ".pod";

	# create the new .pod file
	print "\tcreating $poddir/$file\n" if $verbose;
	open(SPLITOUT, '>', "$poddir/$file") ||
	    die "$0: error opening $poddir/$file for output: $!\n";
	$poddata[$i] =~ s,L<([^<>]*)>,
			defined $heads{anchorify($1)} ? "L<$dir/$1>" : "L<$1>"
		     ,ge;
	print SPLITOUT $poddata[$i]."\n\n";
	print SPLITOUT "=over 4\n\n";
	print SPLITOUT "=item *\n\nBack to L<$dir/\"$prevsec\">\n\n" if $prevsec;
	print SPLITOUT "=item *\n\nForward to L<$dir/\"$nextsec\">\n\n" if $nextsec;
	print SPLITOUT "=item *\n\nUp to L<$dir>\n\n";
	print SPLITOUT "=back\n\n";
	close(SPLITOUT) ||
	    die "$0: error closing $poddir/$file: $!\n";
    }
}


#
# installdir - takes care of converting the .pod and .pm files in the
#  current directory to .html files and then installing those.
#
sub installdir {
    my($dir, $recurse, $podroot, $splitdirs, $ignore) = @_;

    my @dirlist; # directories to recurse on
    my @podlist; # .pod files to install
    my @pmlist;  # .pm files to install

    # should files in this directory get an index?
    my $doindex = (grep($_ eq "$podroot/$dir", @$splitdirs) ? 0 : 1);

    opendir(DIR, "$podroot/$dir")
	|| die "$0: error opening directory $podroot/$dir: $!\n";

    while(readdir DIR) {
	no_upwards($_) or next;
	my $is_dir = -d "$podroot/$dir/$_";
	next if $is_dir and not $recurse;
	my $target
	    = $is_dir    ? \@dirlist
	    : s/\.pod$// ? \@podlist
	    : s/\.pm$//  ? \@pmlist
	    : undef
	    ;
	push @$target, "$dir/$_" if $target;
    }

    closedir(DIR);

    if ($^O eq 'VMS') { s/\.dir$//i for @dirlist }

    # recurse on all subdirectories we kept track of
    foreach $dir (@dirlist) {
	installdir($dir, $recurse, $podroot, $splitdirs, $ignore);
    }

    # install all the pods we found
    foreach my $pod (@podlist) {
	# check if we should ignore it.
	next if $pod =~ m(/t/); # comes from a test file
	next if grep($_ eq "$pod.pod", @$ignore);

	# check if a .pm files exists too
	if (grep($_ eq $pod, @pmlist)) {
	    print  "$0: Warning both '$podroot/$pod.pod' and "
		. "'$podroot/$pod.pm' exist, using pod\n";
	    push(@ignore, "$pod.pm");
	}
	runpod2html("$pod.pod", $doindex);
    }

    # install all the .pm files we found
    foreach my $pm (@pmlist) {
	# check if we should ignore it.
	next if $pm =~ m(/t/); # comes from a test file
	next if grep($_ eq "$pm.pm", @ignore);

	runpod2html("$pm.pm", $doindex);
    }
}


#
# runpod2html - invokes pod2html to convert a .pod or .pm file to a .html
#  file.
#
sub runpod2html {
    my($pod, $doindex) = @_;
    my($html, $i, $dir, @dirs);

    $html = $pod;
    $html =~ s/\.(pod|pm)$/.html/g;

    # make sure the destination directories exist
    @dirs = split("/", $html);
    $dir  = "$htmldir/";
    for ($i = 0; $i < $#dirs; $i++) {
	if (! -d "$dir$dirs[$i]") {
	    mkdir("$dir$dirs[$i]", 0755) ||
		die "$0: error creating directory $dir$dirs[$i]: $!\n";
	}
	$dir .= "$dirs[$i]/";
    }

    # invoke pod2html
    print "$podroot/$pod => $htmldir/$html\n" if $verbose;
    Pod::Html::pod2html(
        "--htmldir=$htmldir",
	"--htmlroot=$htmlroot",
	"--podpath=".join(":", @podpath),
	"--podroot=$podroot",
	"--header",
	($doindex ? "--index" : "--noindex"),
	"--" . ($recurse ? "" : "no") . "recurse",
	"--infile=$podroot/$pod", "--outfile=$htmldir/$html");
    die "$0: error running $pod2html: $!\n" if $?;
}