#!/usr/local/bin/perl
use strict;
use warnings;
use File::Temp qw(tempdir tempfile);
use List::Util qw(reduce sum);

my $tabwidth = 4;

# Open/fetch our JS file.
my $js_file = pop @ARGV;
my $doc_name;
($doc_name = $js_file ) =~ s{.+/}{};
$doc_name =~ s/\..+//;

# Fetch my JavaScript
my $js;
if ( -f $js_file ) {
        # Open my real JavaScript file.
        open my $js_fh, '<', $js_file
                or die "Can't open $js_file: $!";
        local $/;
        $js = <$js_fh>;
}
else {
        # Use the given filename as a URL instead.
        require LWP::Simple;
        $js = LWP::Simple::get( $js_file );
}

# Some *awesome* JavaScript parsing.
my @pod =
        map { unindent( $_ ) . "\n\n=cut\n\n" }
        grep { defined and /\S/ }
        $js =~ m{/(?:\*(.*?)\*/|/([^\n]))}gxs;
unshift @pod, "=cut\n\n";


# Go make a temporary pod file.
my $pod_dir = tempdir( CLEANUP => 1 );
my $pod_file = "$pod_dir/$doc_name.pod";
open my $pod_fh, '>', $pod_file
        or die "Can't create $pod_file: $!";
END { unlink $pod_file }

print {$pod_fh} @pod
        or die "Can't write to $pod_file: $!";
close $pod_fh
  or die "Can't close $pod_file: $!";

# Run our pod file under perldoc.
system 'perldoc', @ARGV, $pod_file;
exit;

sub unindent {
    local $_ = shift @_;

	# Untabify
	s/\t/' ' x $tabwidth/ge;

	# Remove trailing whitespace
	s/\s+\z//;

	# Unindent by finding the largest quantity of removeable
	# whitespace.
	my %leading_space;
	++ $leading_space{length $1}{count}
		while m/^( +)/mg;
	return $_ unless keys %leading_space;
	
	my @indents = sort { $a <=> $b } keys %leading_space;
	
	# Compute the space removed for each indentation level.
	for my $indent_ix ( 0 .. $#indents ) {
		my $indent = $indents[$indent_ix];
		
		my $lines = 0;
		$lines
			+= $leading_space{$indents[$_]}{count}
				for $indent_ix .. $#indents;
		$leading_space{$indent}{space} = $lines * $indent;
	}
	
	# Select the indentation with the most area removed.
	my $suggested_padding
		= reduce {
			my $current_space = $leading_space{$a}{space};
			my $new_space = $leading_space{$b}{space};
			
			$current_space > $new_space ? $a : $b;
		} ( @indents );
	
	# Remove that much from the start of every line.
	s/^ {0,$suggested_padding}//mg;
   
    return $_;
}