#!/usr/bin/perl

use strict;
use warnings;

my %OPTS;
while( $_ = $ARGV[0], /^-/ ) {
    shift;
    last if /^--$/;
    $OPTS{$_} = $_;
}

my $ME = shift;
my $IN = shift;
my $OUT = shift;

if (!$OUT and $IN) {
    ($OUT = $IN) =~ s/\.t$/.$ME/ or $OUT .= ".$ME";
}
unless ($ME and $IN and -e $IN and $OUT) {

    die <<"USAGE";
Usage: $0 [options] implname testfilename [fudgedtestfilename]

    Options:
    --keep-exit-code
        by default, fudge modifies the exit code for fudged test files to 1.
        supplying this option will suppress that behavior.

    Verbs:
    #?implname [num] skip 'reason'
        comment out num tests or blocks and call skip(num)

    #?implname [num] eval 'reason'
        eval num tests or blocks and skip(num) on parsefail

    #?implname [num] try 'reason'
        try num tests or blocks and fail on exception

    #?implname [num] todo 'reason', :by<1.2.3>
        run num tests or blocks with todo() preset

    #?implname emit your_ad_here();
        just pass through your_ad_here();

    #?DOES count
        for all implementations, the following thing does count tests
        (disables any attempt to autocount tests within the construct)
        when construct is a sub, registers the sub name as tester
        (and multiplies calls to tester sub by count tests)

    where
    implname is the lc name of your implementation, e.g. pugs or rakudo
    num is the number of statements or blocks to preprocess, defaults to 1
    count is how many tests the following construct counts as


USAGE
}

if (-e $OUT) {
    if (-M $IN >= -M $OUT and -M $0 >= -M $OUT) {
        print "$OUT\n";     # unchanged, so no need to refudge
        exit(0);
    }
    else {
        unlink $OUT;        # old fudged version, may or may not regenerate...
    }
}

my $REALLY_FUDGED = 0;
my $OUTPUT = "";
my $FUDGE = "";
our $PENDING = 0;
my $ARGS = '';
my $IS = '\\b(?:is|ok|nok|is_deeply|is_approx|isnt|like|unlike|eval_dies_ok|cmp_ok|isa_ok|use_ok|throws_ok|dies_ok|lives_ok|eval_lives_ok|pass|flunk)(?:\\b|_)';
my %DOES;
my $DOES = 0;
my $EXIT = $OPTS{'--keep-exit-code'} ? '' : 'exit(1);';

@ARGV = ($IN);
fudgeblock();

if ($REALLY_FUDGED) {
    open OUT, ">", $OUT or die "Can't create $OUT: $!";
    print OUT $OUTPUT;
    print OUT <<"END";

say "# FUDGED!";
$EXIT
END
    close OUT;
    print "$OUT\n"; # pick the output file to run
}
else {
    print "$IN\n";  # pick the input file to run
}

sub fudgeblock {
    while (<>) {
        if (/^\s*\#\?DOES[:\s] \s* (.*)/x) {
            $DOES = $1;
            next;
        }
        if (/^\s*\#\? (\w+)[:\s] \s* (.*)/x and $1 eq $ME) {
            $REALLY_FUDGED = 1;
            $ARGS = $2;
            if ($ARGS =~ s/^emit\s*//) {
                $_ = $ARGS;
                next;
            }
            if ($ARGS =~ s/^(\d+)\s*//) {
                $PENDING = $1;
            }
            else {
                $PENDING = 1;
            }
            $ARGS =~ s/^(\w+)\s*//;
            $FUDGE = $1;
        }

        next if /^\s*#/;
        next if /^\s*$/;

        if ($DOES) {
            if (/^\s*(sub|multi|proto)\b/) {
                my $tmp = $_;
                $tmp =~ s/^\s*proto\s+//;
                $tmp =~ s/^\s*multi\s+//;
                $tmp =~ s/^\s*sub\s+//;
                $tmp =~ /^(\w+)/;
                $DOES{$1} = $DOES;
                $DOES = 0;
                next;
            }
        }

        next unless $PENDING > 0;

        if (/^\{/) {
            $PENDING--;
            if ($FUDGE eq 'todo') {
                local $PENDING = 999999;    # do all in block as one action
                $OUTPUT .= $_;
                $DOES = 0;  # XXX ignore?
                fudgeblock();
                $_ = '';
            }
            else {
                my $more;
                while (defined($more = <>)) {
                    $_ .= $more;
                    last if $more =~ /^\}/;
                }
                my $numtests = $DOES || do {
                    my $tmp = $_;
                    my $nt = 0;
                    $nt += $1 while $tmp =~ s/^#\?DOES[:\s]\s*(\d+).*\n.*\n//m;
                    if (%DOES) {
                            my $does = join('|',keys(%DOES));
                            $nt += $DOES{$1} while $tmp =~ s/^\s*($does)\b//mx;
                    }
                    $nt += () = $tmp =~ m/^(\s*$IS)/mgx;
                    $nt;
                };
                if ($FUDGE eq 'skip') {
                    s/^/# /mg;
                    $_ = "skip($numtests, $ARGS);" . $_;
                }
                elsif ($FUDGE eq 'try') {
                    chomp;
                    $_ = "(try $_) // flunk($ARGS);\n";
                }
                elsif ($FUDGE eq 'eval') {
                    chomp;
                    s/(['\\])/\\$1/g;
                    $_ = "eval('$_') // skip($numtests, $ARGS);\n";
                }
                else {
                    warn "Don't know how to mark block for $FUDGE!\n";
                }
            }
        }
        else {
            if ($FUDGE eq 'todo') {
                $DOES = 0;  # XXX ignore?
                $PENDING -= s/^(\s*)/${1}todo($ARGS); / if /^\s*$IS/;
            }
            else {
                while ($_ !~ /;[ \t]*(#.*)?$/) {
                    my $more = <>;
                    last unless $more;
                    $_ .= $more;
                }
                my ($keyword) = /^\s*(\w+)/ || '';
                my $numtests;
                if ($DOES{$keyword}) {
                    $numtests = $DOES{$keyword};
                }
                elsif ($DOES) {
                    $numtests = $DOES;
                }
                else {
                    next unless /^\s*$IS/;
                    $numtests = 1;
                }
                $PENDING--;
                $_ = "{ " . $_ . " }";
                if ($FUDGE eq 'skip') {
                    s/^/# /mg;
                    $_ = "skip($numtests,$ARGS); $_\n";
                }
                elsif ($FUDGE eq 'try') {
                    $_ = "(try $_) // flunk($ARGS);\n";
                }
                elsif ($FUDGE eq 'eval') {
                    s/(['\\])/\\$1/g;
                    $_ = "eval('$_') // skip($numtests,$ARGS);\n";
                }
                else {
                    warn "Don't know how to mark statement for $FUDGE!\n";
                }
            }
        }
    }
    continue {
        $OUTPUT .= $_;
        return if /^\}/ and $PENDING > 0;
    }
}