#!/usr/bin/perl



sub begin {
    @exclude_calls = qw(chomp chop chr crypt hex index lc lcfirst length oct ord pack reverse rindex sprintf substr uc ucfirst pos quotemeta split study abs atan2 cos exp hex int log oct rand sin sqrt srand pop push shift splice unshift grep join map reverse sort unpack delete each exists keys values binmode close closedir dbmclose dbmopen die eof fileno flock format getc print printf read readdir rewinddir seek seekdir select syscall sysread sysseek syswrite tell telldir truncate warn write pack read syscall sysread syswrite unpack vec chdir chmod chown chroot fcntl glob ioctl link lstat mkdir open opendir readlink rename rmdir stat symlink umask unlink utime caller continue die do dump eval exit goto last next redo return sub wantarray caller import local my package use defined dump eval formline local my reset scalar undef wantarray alarm exec fork getpgrp getppid getpriority kill pipe setpgrp setpriority sleep system times wait waitpid do import no package require use bless dbmclose dbmopen package ref tie tied untie use accept bind connect getpeername getsockname getsockopt listen recv send setsockopt shutdown socket socketpair msgctl msgget msgrcv msgsnd semctl semget semop shmctl shmget shmread shmwrite endgrent endhostent endnetent endpwent getgrent getgrgid getgrnam getlogin getpwent getpwnam getpwuid setgrent setpwent endprotoent endservent gethostbyaddr gethostbyname gethostent getnetbyaddr getnetbyname getnetent getprotobyname getprotobynumber getprotoent getservbyname getservbyport getservent sethostent setnetent setprotoent setservent gmtime localtime time times abs bless chomp chr exists formline glob import lc lcfirst map my no prototype qx qw readline readpipe ref sysopen tie tied uc ucfirst untie use qq Dumper packdrake Eth);
    @exclude_calls{@exclude_calls} = undef;

    @exclude_uses = qw(globals diagnostics strict vars lib Carp Config Exporter Socket Storable Locale::GetText CORE POSIX Gtk Data::Dumper CGI Net::FTP Gtk::XmHTML Gtk::Gdk Gtk::Gdk::ImlibImage Gtk::Gdk::Pixbuf Newt Newt::Component Newt::Grid DynaLoader IO::Socket Date::Manip packdrake XML::Parser);

    while ($ARGV[0] =~ /-I(.*)/) {
	push @I, $1;
	shift @ARGV;
    }

    $NO_CW = $ARGV[0] eq "-no_cw" and shift @ARGV;
    $USES = $ARGV[0] eq "-uses" and shift @ARGV;


    @I = ('.', '..');

    foreach (@I) {
	open F, "$_/.perl_checker" or next;
	foreach (<F>) {
	    chomp;
	    push @exclude_uses, $_;
	}
    }

    unshift @INC, @I;
    @exclude_uses{@exclude_uses} = undef;

    if (!$NO_CW) {
	foreach (@ARGV) {
	    system("perl", (map {; "-I", $_ } @I), "-cw", $_);
	    $? == 0 or die "perl -cw $_ failed\n";
	}
    }
}

begin();

while (@ARGV) {
    $prev_ARGV = $ARGV;
    $ARGV = shift @ARGV;

    $package = 'main';
    $. = 0;
    open F, $ARGV or die "can't open file $ARGV\n";
    while (<F>) {
	chop;

	if ($. == 1 && $ARGV =~ /\.pm$/ && !/^package\b/) {
	    warn_(qq(module $ARGV does not have "package xxxx;" on its first line), info());
	}

	if (/^# perl_checker: RE-EXPORT-ALL/) {
	    push @re_exported, $package;
	}

	if (/^=(head|begin)/ .. /^=cut/) {
          die "missing =cut in $prev_ARGV\n" if $. == 1;
          next;
        }
	/^\s*#/ and next;

	$explicit_no_warning = /#-#/;

	if (/^\s*require\s+([\w:]+);/) {
	    add_use($1);
	} elsif (my ($r) = /^\s*require (.*)/) {
	    $r =~ /'(.*)'/ or err("<<$_>> should be formatted like <<require 'PACKAGE.pm'>>", info());
	    $r =~ m|'([^/]*)\.pm'| and add_use($1);
	    next;
	}

	syntax_warnings();
	drop_strings_and_regexps();
	syntax_warnings_after_removing_strings_and_regexps();
	get_exports();

    
	while (/(^|[^\$@\w:>\\]) # first a char
	        ((\w|:)*\w)      # function name
	        (?=\()         # a open parenthesis (zero-width lookahead)
	    /gx) {
	    my $f = $2;
	    add_call($f) if !/$f\(s\)/; # special case xxxx(s) excluded cuz' of strings containing it
	}
	while (/&([\w:]+)/g) { add_call($1); }
	
	
	/^use\s+([\w:]+);/ and add_use($1);
	if (my ($p, $v) = /^use\s([\w:]+)\s+(.*)/) {
	    $v =~ /^qw\((.*?)\)/ ? add_use($p, $1) : err("<<$_>> should be written <<use $p qw(:A :B ...)>>", info())
	      if !exists $exclude_uses{$p};
	}
	if (my ($p, $v) = /^\s*(\S+)->import\((.*)\)/) {
	    $v =~ /^qw\((.*?)\)/ ? add_use($p, $1) : err("<<$_>> should be written << $p->import(qw(:A :B ...))>>", info());
	}
	/^\s*sub\s+(\w+)/ and $sub{$package}->{$1} = 1;	
    }
    close F;
}

$explicit_no_warning = 0;
end();

sub drop_strings_and_regexps {
    s/"[^"]*"/"foo"/g;  #"
    s/'[^']*'/'foo'/g;  #'
    s/\bqq\([^)]*\)/'foo'/g;
    s/\bm\b([\/|!,])(.*?)\1/m!foo!/g; # m// operator: "m/re/", "m|re|", ...
    s/\bs\b([\/|!,])(.*?)\1(.*?)\1/s!foo!bar!/g; # s/// operator: "s/re/.../", "s|re|...|", ...
    s|\(/.*?/|(/foo/|g; # m// operator: "(/re/"
    s{([!=]~|\bif\b)\s*/.*?/}{$1 /foo/}g; # m// operator: "if /re/", "=~ /re/", "!~ /re/"
    
    s/#.*//;
}

sub get_exports {
    if (/^\s*package ([\w:]+)/) {
        $package = $1;
        $path{$package} ||= ($ARGV =~ m|(.*/)|)[0];
    }
    
    
    if (/\@EXPORT = qw\((.*)\)/) {
        @{$export{$package}}{split ' ', $1} = undef;
    }
    if (/\@EXPORT_OK = qw\((.*)\)/) {
        @{$export_ok{$package}}{split ' ', $1} = undef;
        $export_info{$package} = info();
    }
    if (/%EXPORT_TAGS = \((\w+) => \[ \@EXPORT_OK \]\)/) {
        $export_tags{$package}->{$1} = $export_ok{$package};
    }
    if (/%EXPORT_TAGS = \(\s*$/ .. /^\);$/) {
        /\s+(\w+)\s+.*?qw\((.*)\)/;
        @{$export_tags{$package}->{$1}}{split ' ', $2} = undef;
        $export_tags_info{$package}->{$1} = info();
    }
}

sub syntax_warnings {

    if (/\W("\$\w+")/ && !/qq\(/ && !/^\s*case "\$/ && !/\b[A-Z]\w*\s+"\$\w+"/) {
	warn_(qq($1 is better written without the double quotes), info());
    }

    if (/^\s*my\b[^;]*=\s*(\(\)|undef);/) {
        warn_(q(no need to initialize variables, it's done by default), info());
    }
    
    if (/[^#\s)}\]]\s+\)/) {
        warn_(q(spurious space before closing parenthesis), info());
    }
    
    if (/;\s*\}/) {
        warn_(q(spurious ";" before closing block), info());
    }
    
    if (/(.*\s\{)[^\s{}]/ && !/\{[\d,]+\}/ && !/Usage:/) { #- eg of Usage: cmd {foo|bar}
        warn_(qq(missing space after "$1"), info());
    }
    
    if (/\{\s[^{}]*[^\s{}]\}/) {
        warn_(qq(missing space before "}$'"), info());
    }

    if (/(\$\w+)\s*=\s+.*\s+((if\s+!|unless)\s*\1);/) {
	warn_(qq("$1 = ... $2" can be written "$1 ||= ..."), info());
    }

    if (my ($infix, $cond) = /\S\s+(if|unless|foreach)\s+(\([^,]*\));?$/) {
	if (remove_parentheses($cond) eq '') {
	    warn_(qq(''... $1 ($2)'' can be written ''... $1 $2''), info());
	}
    }

    if (my ($cond) = /\bunless\s+(\(.*?\))\s+{/ ? $1 : /\bunless\s+([^;]*);?$/) {
	if (remove_funcalls($cond) =~ /(!|&&|\|\|)/) {
	    warn_(qq(don't use "unless" when the condition is complex, use "if" instead), info());
	}
    }
    
    if (/%_\W/ || /[^@]\$_{/) { #-#
        err(q(do not use %_), info()); #-#
    }
    if (/\$_\s*=~/) {
        warn_(q(``$_ =~ /regexp/'' can be written ``/regexp/''), info());
    }
    if (/\$_\s*!~/) {
        warn_(q(``$_ !~ /regexp/'' can be written ``!/regexp/''), info());
    }
    if (/my \$\w+\s*=~/ || /my \(\$\w+\)\s*=~/) {
        err(q(applying =~ on a new initialized variable is wrong), info());
    }
    if (/[}>]{(['"])([a-z][a-z0-9_]*)\1}/i) {
        warn_(qq(``{$1$2$1}'' can be written ``{$2}''), info())
          if $2 ne 'x' && $2 ne 'y'; 
          # special case for {'y'} otherwise the emacs mode goes wild
          # special case for {'x'} to have the same as {'y'} (since they usually go together)
    }
    if (/%\$\w+(->|\{)/ || /%\{([^{}]|\{[^{}]*\})*\}(->|\{)/ ||
        /@\$\w+->/      || /@\{([^{}]|\{[^{}]*\})*\}->/) {
        err(q(bad expression, tell pixel@mandrakesoft.com), info());
    }
    
    if (/\blength(\s*|\()\@/) {
        err(q(never use ``length @l'', it returns the length of the string int(@l)), info());
    }
    
    if (/\blocal\b.*\|\|=/) {
        err(q(never use ``local $var ||= <val>'', write ``local $var = $var || <val>''), info());
    }
    
    if (/\bsub\b\s*\{[^{}]*\$_(?!\[)/) {
        warn_(q(using $_ in a sub is generally bad news), info()) if !/local\s+\$_/;
    }
    
    if ((my ($op) = /([<>]{2})/) && (/[+-]\s*[\w\$]+\s*[<>]{2}/ || /[<>]{2}\s*[\w\$]+\s*[+-]/) && !/\<\<[A-Z]/) { # don't warn for here-document alike
        err(qq(parentheses needed around operator $op), info());
    }
    if (/=.*:\s*\$\w+\s*=/) {
        err(q(do not use ``cond ? $v1 = XX1 : $v2 = XX2'' which is parsed as ``(cond ? $v1 = XX1 : $v2) = XX2''), info());
    }

    if (my ($f, $s) = /(N_?)\((.*)/) {
	$s =~ s/\\"//g;
	$s =~ s/"([^"]*)($|".*)/$1/ or err(qq($f must be used as $f("xxx") for xgettext to work correctly (hint: use translate instead)), info());
	$s =~ s/\\[\$@]//g;
	$s !~ /[\$@]/ or err(qq(don't use interpolated translated string, use %s or %d instead), info());
    }    

    if (my (undef, $stash) = /\bopen(\(|\s+)(\w+),/) {
	if ($stash !~ /^(STDIN|STDOUT|STDERR)$/ && (/\local \*(\w+)/ ? $1 : $stash_localised) ne $stash) {
	    err(qq(you must localize $stash ("local *$stash;" must be on the previous line)), info());
	}
    }
    ($stash_localised) = /\blocal \*(\w+)/;

    if (/\bwhile \(</ && !/\blocal \$_;/ && !$underscore_localised) {
	err(q(expression while (<FILEHANDLE>) ... modifies $_, localize it first (it must be on the previous line)), info());
    }
    $underscore_localised = /\blocal \$_;/;

    if (/\bfor\s+my/ || /\bfor\b\s*\([^;]*$/ && !/\bfor\b\s*\(\$[^),\s]*\)/) { #- for is allowed with the meaning of "with" in Pascal
	err(q(use "foreach" instead of "for" (these are synonyms, but foreach has been chosen to be the default)), info());
    }
}

sub syntax_warnings_after_removing_strings_and_regexps {
    local $_ = $_;
    s/\bqw\([^)]*\)/'foo'/g;

    if (my ($before, $f, $pkg, $after) = /(.*[^a-zA-Z0-9_:@*%&\$])((\w+::)+\w+)\s*([^a-zA-Z0-9_(: {].*)/) {
	if ($before !~ /(sub|use|package|require|new|->)\s*$/ && $after !~ /^->/) {
	    $pkg =~ s/::$//;
	    warn_(qq($f must be written $f() otherwise it will not work if "use $pkg" is replaced by "require $pkg"), info());
	}
    }

    if (/\}->([{\[])/) {
	warn_(qq("}->$2" is better written "}$2"), info());
    }

    if (/[\w>}]\[[^\]\[]*\]->([{\[])/) {
	warn_(qq("]->$2" is better written "]$2"), info());
    }

    if (/([\$@%]\w+=)[^~]/) {
        warn_(qq(missing space before "=" in $1), info());
    }
    
    if (/\(\s+[^#\s({\[]/) {
        warn_(q(spurious space after opening parenthesis), info());
    }

    if (/;([^\s\\].{0,10})/ && !/^sub/ && !/;-\)/ && !/^\s+;;$/) {
        warn_(qq(missing space after ";$1"), info());
    }
}

sub add_call {
    $explicit_no_warning and return;
    $_[0] =~ /^\d/ and return;
    exists $exclude_calls{$_[0]} and return;
    $call{$package}->{$_[0]} = 1;
    $call_info{$package}->{$_[0]} = info()
}

sub add_use {
    my ($p, $op) = @_;
    exists $exclude_uses{$p} and return;

    warn_("uses $p", info()) if $USES;

    my $already = $use_info{$package}->{$p};
#    warn_("reused " . $already->{file} . " " . $already->{line}, info()) if $already && $ARGV ne $already->{file};

    $use{$package}->{$p} ||= []; # create it

    foreach (split ' ', $op) {
	if (/^:(.*)/) {
	    push @{$use_tags{$package}->{$p}}, $1;
	} else {
	    push @{$use{$package}->{$p}}, $_;
	}
    }
	    
    $use_info{$package}->{$p} = info();

    $path{$p} and return;
    my ($path, $f) = "$p.pm" =~ /(.*::)?(.*)/;
    $path =~ s|::|/|g;
    
    $path{$p} = updirs($path{$package}, (($package =~ tr/://) / 2));
    foreach ($path{$p}, @INC) {
	$_ .= "/" if !m|/$|;
	my $file = "$_$path$f";
	if (-e $file) {
	    push @ARGV, $file;
	    $file2package{$file} = $p;
	    return;
	}
    }
    err("can't find package $p", info());
}

#sub add_usevar {
#    length $_[0] <= 3 and return;
#    $usevar{$package}->{$_[0]} = 1;
#    $usevar_info{$package}->{$_[0]} = info();
#}

sub info { { file => $ARGV, line => $. } }

sub updirs {
    my ($p, $i) = @_;
    for (; $i && $p =~ s|[^/]+/^||; $i--) {}
    for (; $i ; $i--) { $p .= "../"; }
    $p;
}


sub err {
    return if $explicit_no_warning;

    $ERR = 1;
    &warn_;
}
sub warn_ {
    return if $explicit_no_warning;

    my ($m, $i) = @_;
    if ($i) {
	 print STDERR "$i->{file}:$i->{line}: $m\n";
    } else {
	 print STDERR "$m\n";
    }
}

sub end {
    foreach my $package (reverse @re_exported) {
	my $h = $export{$package} ||= {};
	%$h = (%$h, 
	       (map { %{$export{$_}} } keys %{$use{$package}}),
	       (map { %$_ } map { values %{$export_tags{$_}} } keys %{$use{$package}}),
	       );
    }

#    while (my ($package, $vars) = each %usevar) {
#	 my @l = grep { ! $defvar{$package}->{$_} } keys %$vars;
#	 @l and print "$package: uses vars (", join(' ', @l), ")";
#    }

    while (my ($package, $calls) = each %call) {
        here: foreach my $func_verbatim (keys %$calls) {

	    my ($pkg, $func) = do {
		if ($func_verbatim =~ /(.*)::(.*)/) {
		    exists $exclude_uses{$1} and next;
		    exists $use{$package}->{$1} or err("you must <<use $1>> for function $2", $call_info{$package}->{$func_verbatim});
		    $1, $2;
		} else {
		    $package, $func_verbatim;
		}
	    };
	    $sub{$pkg}->{$func} and next; # defined in own package
	    
	    foreach my $k (keys %{$use{$pkg}}) {
		exists $export{$k}->{$func} and next here; # ok, exported by $k

		foreach (@{$use_tags{$pkg}->{$k}}) {
		    exists $export_tags{$k}->{$_}->{$func} and next here; # ok, exported by $k in tag $_
		}
	    }
	    err("$func_verbatim undefined", $call_info{$package}->{$func_verbatim}) if $func_verbatim ne 'q';
	}
    }
    $ERR and exit $ERR;
}

sub remove_parentheses {
    my ($s) = @_;
    while ($s =~ s/\([^()]*\)//g) {}
    $s;
}

sub remove_funcalls {
    my ($s) = @_;
    my $r = '';
    while (my ($prev, $next) = $s =~ /^(.*?\w+)(\(.*)/) {
	$r .= "$prev()";
	$s = $next;
	while ($s =~ /^\(/) {
	    $s =~ s/\([^()]*\)//g or return $r;
	}
    }
    "$r$s";
}