#!/usr/bin/env perl

# Generate ZSH completion

use strict;
use warnings;

my $curl = $ARGV[0] || 'curl';

my $regex = '\s+(?:(-[^\s]+),\s)?(--[^\s]+)\s([^\s.]+)?\s+(.*)';
my @opts = parse_main_opts('--help', $regex);

my $opts_str;

$opts_str .= qq{  $_ \\\n} foreach (@opts);
chomp $opts_str;

my $tmpl = <<"EOS";
#compdef curl

# curl zsh completion

local curcontext="\$curcontext" state state_descr line
typeset -A opt_args

local rc=1

_arguments -C -S \\
$opts_str
  '*:URL:_urls' && rc=0

return rc
EOS

print $tmpl;

sub parse_main_opts {
    my ($cmd, $regex) = @_;

    my @list;
    my @lines = call_curl($cmd);

    foreach my $line (@lines) {
        my ($short, $long, $arg, $desc) = ($line =~ /^$regex/) or next;

        my $option = '';

        $desc =~ s/'/'\\''/g if defined $desc;
        $desc =~ s/\[/\\\[/g if defined $desc;
        $desc =~ s/\]/\\\]/g if defined $desc;

        $option .= '{' . trim($short) . ',' if defined $short;
        $option .= trim($long)  if defined $long;
        $option .= '}' if defined $short;
        $option .= '\'[' . trim($desc) . ']\'' if defined $desc;

        $option .= ":'$arg'" if defined $arg;

        $option .= ':_files'
            if defined $arg and ($arg eq '<file>' || $arg eq '<filename>'
                || $arg eq '<dir>');

        push @list, $option;
    }

    # Sort longest first, because zsh won't complete an option listed
    # after one that's a prefix of it.
    @list = sort {
        $a =~ /([^=]*)/; my $ma = $1;
        $b =~ /([^=]*)/; my $mb = $1;

        length($mb) <=> length($ma)
    } @list;

    return @list;
}

sub trim { my $s = shift; $s =~ s/^\s+|\s+$//g; return $s };

sub call_curl {
    my ($cmd) = @_;
    my $output = `"$curl" $cmd`;
    if ($? == -1) {
        die "Could not run curl: $!";
    } elsif ((my $exit_code = $? >> 8) != 0) {
        die "curl returned $exit_code with output:\n$output";
    }
    return split /\n/, $output;
}