#!/usr/bin/perl -w

# Copyright (C) 2014 Apple Inc. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# 1.  Redistributions of source code must retain the above copyright
#     notice, this list of conditions and the following disclaimer. 
# 2.  Redistributions in binary form must reproduce the above copyright
#     notice, this list of conditions and the following disclaimer in the
#     documentation and/or other materials provided with the distribution. 
# 3.  Neither the name of Apple Inc. ("Apple") nor the names of
#     its contributors may be used to endorse or promote products derived
#     from this software without specific prior written permission. 
#
# THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

use strict;

use Cwd;
use File::Basename;
use FindBin;
use Getopt::Long;

my $shouldPrintWarnings = 1;
my $shouldShowHelp;
my $shouldBeVerbose;

my $getOptionsResult = GetOptions(
    'h|help' => \$shouldShowHelp,
    'w|warnings!' => \$shouldPrintWarnings,
);

if (!$getOptionsResult || $shouldShowHelp) {
    print STDERR <<END;
Usage: @{[ basename($0) ]} [options] [path/to/file.exp.in ...]
  -h|--help           show this help message
  -v|--verbose        include verbose output about progress
  -w|--[no-]warnings  show or suppress warnings (default: show warnings)
END
    exit 1;
}

if (!scalar @ARGV) {
    my $prefix = "$FindBin::RealBin/Source/";
    $prefix =~ s|/Tools\/Scripts/|/| or die "ERROR: Script not in Tools/Scripts\n";
    my $currentDirectory = cwd();
    $prefix =~ s|^\Q$currentDirectory\E/||;
    @ARGV = (
        $prefix . "WebCore/WebCore.exp.in",
        $prefix . "WebKit/mac/WebKit.exp",
        $prefix . "WebKit/mac/WebKit.mac.exp",
    );
}

my @conditionalStack = ();
my %symbols = ();

sub pushConditional($);
sub negateTopConditional();
sub popTopConditional();
sub addSymbol($);
sub serializeAll();

my $sawError = 0;
my $exitStatus = 0;

sub sawError($)
{
    my $error = shift;

    warn "ERROR: $error";
    $sawError = 1;
    $exitStatus = 1;
}

for my $exportFile (@ARGV) {
    if ($exportFile !~ /\.exp(\.in)?$/) {
        print STDERR "WARNING: Not an export file: $exportFile\n" if $shouldPrintWarnings;
        next;
    }

    print STDERR "Sorting $exportFile\n";

    $sawError = 0;
    my $before = "";

    @conditionalStack = ();
    %symbols = ();

    open IN, "<", $exportFile or die "Could not open $exportFile: $!";
    while (my $line = <IN>) {
        $before .= $line;
        next if $line =~ /^\s*$/;
        if ($line =~ /^\#if (.+)$/) {
            pushConditional($1);
            next;
        }
        if ($line =~ /^\#else$/) {
            negateTopConditional() or sawError("#else without matching #if");
            next;
        }
        if ($line =~ /^\#endif$/) {
            popTopConditional() or sawError("#endif without matching #if");
            next;
        }
        if ($line =~ /^(\.?[A-Za-z0-9_\?]+)$/) {
            addSymbol($1);
            next;
        }
        if ($line =~ /^  \"(\.?[A-Za-z0-9_\?]+)\", referenced from:$/) { # For easy paste from build errors
            addSymbol($1);
            next;
        }
        if ($line =~ /^      .+ in .+\.o$/) { # For easy paste from build errors
            next;
        }
        chomp $line;
        sawError("Could not parse: \"$line\"");
    }
    close IN;

    next if $sawError;

    my $after = serializeAll();

    if ($before eq $after) {
        print STDERR "Leaving $exportFile alone since it is already sorted\n" if $shouldBeVerbose;
    } else {
        print STDERR "Writing sorted $exportFile\n" if $shouldBeVerbose;
        open OUT, ">", $exportFile or die "Could not overwrite $exportFile: $!";
        print OUT $after;
        close OUT;
    }
}

exit $exitStatus;

sub makeExpressionCanonical($)
{
    my $expression = shift;

    # PLATFORM(MAC) and PLATFORM(IOS) are mutually exclusive.
    $expression =~ s/!PLATFORM\(IOS\)/PLATFORM(MAC)/g;
    $expression =~ s/!PLATFORM\(MAC\)/PLATFORM(IOS)/g;

    return $expression;
}

sub negateExpression($)
{
    my $expression = shift;

    return makeExpressionCanonical(substr $expression, 1) if $expression =~ /^\!/;
    return makeExpressionCanonical("!" . $expression) unless $expression =~ /\s/;
    return makeExpressionCanonical("!(" . $expression . ")");
}

sub pushConditional($)
{
    my $expression = shift;

    push @conditionalStack, makeExpressionCanonical($expression);
}

sub negateTopConditional()
{
    return 0 if !scalar @conditionalStack;
    push @conditionalStack, negateExpression(pop @conditionalStack);
    return 1;
}

sub popTopConditional()
{
    return 0 if !scalar @conditionalStack;
    pop @conditionalStack;
    return 1;
}

sub addSymbol($)
{
    my $symbol = shift;

    $symbols{serializeConditionalStack()}{$symbol} = 1;
}

sub serializeConditionalStack()
{
    return join ' && ', @conditionalStack;
}

sub compareExpressions
{
    my $mungedA = $a;
    my $mungedB = $b;

    # NSGEOMETRY_TYPES_SAME_AS_CGGEOMETRY_TYPES
    $mungedA =~ s/\bNSGEOMETRY_TYPES_SAME_AS_CGGEOMETRY_TYPES\b/000/g;
    $mungedB =~ s/\bNSGEOMETRY_TYPES_SAME_AS_CGGEOMETRY_TYPES\b/000/g;

    # NDEBUG
    $mungedA =~ s/\bNDEBUG\b/001/g;
    $mungedB =~ s/\bNDEBUG\b/001/g;

    # ASSERT_DISABLED and LOG_DISABLED
    $mungedA =~ s/(\w+)_DISABLED/002$1/g;
    $mungedB =~ s/(\w+)_DISABLED/002$1/g;

    # PLATFORM(MAC)
    $mungedA =~ s/\bPLATFORM\(MAC/010/g;
    $mungedB =~ s/\bPLATFORM\(MAC/010/g;

    # PLATFORM(IOS)
    $mungedA =~ s/\bPLATFORM\(IOS/011/g;
    $mungedB =~ s/\bPLATFORM\(IOS/011/g;

    # USE(X) sorts under X, not USE
    $mungedA =~ s/\b(\w+)\((.+?)\)/$2:$1/g;
    $mungedB =~ s/\b(\w+)\((.+?)\)/$2:$1/g;

    # Negated version of a condition sorts just after that condition.
    $mungedA =~ s/\!\((.+)\)/$1~/g;
    $mungedA =~ s/\!(.+)/$1~/g;
    $mungedB =~ s/\!\((.+)\)/$1~/g;
    $mungedB =~ s/\!(.+)/$1~/g;

    return $mungedA cmp $mungedB;
}

sub serializeAll()
{
    my $result = "";
    foreach my $expression (sort compareExpressions keys %symbols) {
        $result .= "\n" if $result ne "";
        $result .= "#if $expression\n" if $expression ne "";
        foreach my $symbol (sort keys %{$symbols{$expression}}) {
            $result .= "$symbol\n";
        }
        $result .= "#endif\n" if $expression ne "";
    }
    return $result;
}