#!/usr/bin/perl

my $some_dir=".";

opendir(my $dh, $some_dir) || die "Can't opendir $some_dir: $!";
my @s = grep { /\.d$/ && -f "$some_dir/$_" } readdir($dh);
closedir $dh;

my %optshort;
my %optlong;
my %helplong;
my %arglong;
my %redirlong;
my %protolong;

# get the long name version, return the man page string
sub manpageify {
    my ($k)=@_;
    my $l;
    if($optlong{$k} ne "") {
        # both short + long
        $l = "\\fI-".$optlong{$k}.", --$k\\fP";
    }
    else {
        # only long
        $l = "\\fI--$k\\fP";
    }
    return $l;
}

sub printdesc {
    my @desc = @_;
    for my $d (@desc) {
        # skip lines starting with space (examples)
        if($d =~ /^[^ ]/) {
            for my $k (keys %optlong) {
                my $l = manpageify($k);
                $d =~ s/--$k([^a-z0-9_-])/$l$1/;
            }
        }
        print $d;
    }
}

sub seealso {
    my($standalone, $data)=@_;
    if($standalone) {
        return sprintf
            ".SH \"SEE ALSO\"\n$data\n";
    }
    else {
        return "See also $data. ";
    }
}

sub overrides {
    my ($standalone, $data)=@_;
    if($standalone) {
        return ".SH \"OVERRIDES\"\n$data\n";
    }
    else {
        return $data;
    }
}

sub protocols {
    my ($standalone, $data)=@_;
    if($standalone) {
        return ".SH \"PROTOCOLS\"\n$data\n";
    }
    else {
        return "($data) ";
    }
}

sub added {
    my ($standalone, $data)=@_;
    if($standalone) {
        return ".SH \"ADDED\"\nAdded in curl version $data\n";
    }
    else {
        return "Added in $data. ";
    }
}

sub single {
    my ($f, $standalone)=@_;
    open(F, "<$f") ||
        return 1;
    my $short;
    my $long;
    my $tags;
    my $added;
    my $protocols;
    my $arg;
    my $mutexed;
    my $requires;
    my $seealso;
    my $magic; # cmdline special option
    while(<F>) {
        if(/^Short: *(.)/i) {
            $short=$1;
        }
        elsif(/^Long: *(.*)/i) {
            $long=$1;
        }
        elsif(/^Added: *(.*)/i) {
            $added=$1;
        }
        elsif(/^Tags: *(.*)/i) {
            $tags=$1;
        }
        elsif(/^Arg: *(.*)/i) {
            $arg=$1;
        }
        elsif(/^Magic: *(.*)/i) {
            $magic=$1;
        }
        elsif(/^Mutexed: *(.*)/i) {
            $mutexed=$1;
        }
        elsif(/^Protocols: *(.*)/i) {
            $protocols=$1;
        }
        elsif(/^See-also: *(.*)/i) {
            $seealso=$1;
        }
        elsif(/^Requires: *(.*)/i) {
            $requires=$1;
        }
        elsif(/^Help: *(.*)/i) {
            ;
        }
        elsif(/^---/) {
            if(!$long) {
                print STDERR "WARN: no 'Long:' in $f\n";
            }
            last;
        }
        else {
            chomp;
            print STDERR "WARN: unrecognized line in $f, ignoring:\n:'$_';"
        }
    }
    my @dest;
    while(<F>) {
        push @desc, $_;
    }
    close(F);
    my $opt;
    if(defined($short) && $long) {
        $opt = "-$short, --$long";
    }
    elsif($short && !$long) {
        $opt = "-$short";
    }
    elsif($long && !$short) {
        $opt = "--$long";
    }

    if($arg) {
        $opt .= " $arg";
    }

    if($standalone) {
        print ".TH curl 1 \"30 Nov 2016\" \"curl 7.52.0\" \"curl manual\"\n";
        print ".SH OPTION\n";
        print "curl $opt\n";
    }
    else {
        print ".IP \"$opt\"\n";
    }
    if($protocols) {
        print protocols($standalone, $protocols);
    }

    if($standalone) {
        print ".SH DESCRIPTION\n";
    }

    printdesc(@desc);
    undef @desc;

    my @foot;
    if($seealso) {
        my @m=split(/ /, $seealso);
        my $mstr;
        for my $k (@m) {
            my $l = manpageify($k);
            $mstr .= sprintf "%s$l", $mstr?" and ":"";
        }
        push @foot, seealso($standalone, $mstr);
    }
    if($requires) {
        my $l = manpageify($long);
        push @foot, "$l requires that the underlying libcurl".
            " was built to support $requires. ";
    }
    if($mutexed) {
        my @m=split(/ /, $mutexed);
        my $mstr;
        for my $k (@m) {
            my $l = manpageify($k);
            $mstr .= sprintf "%s$l", $mstr?" and ":"";
        }
        push @foot, overrides($standalone, "This option overrides $mstr. ");
    }
    if($added) {
        push @foot, added($standalone, $added);
    }
    if($foot[0]) {
        print "\n";
        my $f = join("", @foot);
        $f =~ s/ +\z//; # remove trailing space
        print "$f\n";
    }
    return 0;
}

sub getshortlong {
    my ($f)=@_;
    open(F, "<$f");
    my $short;
    my $long;
    my $help;
    my $arg;
    my $protocols;
    while(<F>) {
        if(/^Short: (.)/i) {
            $short=$1;
        }
        elsif(/^Long: (.*)/i) {
            $long=$1;
        }
        elsif(/^Help: (.*)/i) {
            $help=$1;
        }
        elsif(/^Arg: (.*)/i) {
            $arg=$1;
        }
        elsif(/^Protocols: (.*)/i) {
            $protocols=$1;
        }
        elsif(/^---/) {
            last;
        }
    }
    close(F);
    if($short) {
        $optshort{$short}=$long;
    }
    if($long) {
        $optlong{$long}=$short;
        $helplong{$long}=$help;
        $arglong{$long}=$arg;
        $protolong{$long}=$protocols;
    }
}

sub indexoptions {
  foreach my $f (@s) {
    getshortlong($f);
  }
}

sub header {
    my ($f)=@_;
    open(F, "<$f");
    my @d;
    while(<F>) {
        push @d, $_;
    }
    close(F);
    printdesc(@d);
}

sub listhelp {
    foreach my $f (sort keys %helplong) {
        my $long = $f;
        my $short = $optlong{$long};
        my $opt;

        if(defined($short) && $long) {
            $opt = "-$short, --$long";
        }
        elsif($long && !$short) {
            $opt = "    --$long";
        }

        my $arg = $arglong{$long};
        if($arg) {
            $opt .= " $arg";
        }

        my $line = sprintf " %-19s %s\n", $opt, $helplong{$f};

        if(length($line) > 79) {
            print STDERR "WARN: the --$long line is too long\n";
        }
        print $line;
    }
}

sub mainpage {
    # show the page header
    header("page-header");

    # output docs for all options
    foreach my $f (sort @s) {
        single($f, 0);
    }

    header("page-footer");
}

sub showonly {
    my ($f) = @_;
    if(single($f, 1)) {
        print STDERR "$f: failed\n";
    }
}

sub showprotocols {
    my %prots;
    foreach my $f (keys %optlong) {
        my @p = split(/ /, $protolong{$f});
        for my $p (@p) {
            $prots{$p}++;
        }
    }
    for(sort keys %prots) {
        printf "$_ (%d options)\n", $prots{$_};
    }
}

sub getargs {
    my $f;
    do {
        $f = shift @ARGV;
        if($f eq "mainpage") {
            mainpage();
            return;
        }
        elsif($f eq "listhelp") {
            listhelp();
            return;
        }
        elsif($f eq "single") {
            showonly(shift @ARGV);
            return;
        }
        elsif($f eq "protos") {
            showprotocols();
            return;
        }
    } while($f);

    print "Usage: gen.pl <mainpage/listhelp/single FILE/protos>\n";
}

#------------------------------------------------------------------------

# learn all existing options
indexoptions();

getargs();