#!/usr/bin/env perl
#
# Copyright (C) 2011 Google Inc.  All rights reserved.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Library General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Library General Public License for more details.
#
# You should have received a copy of the GNU Library General Public License
# along with this library; see the file COPYING.LIB.  If not, write to
# the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
# Boston, MA 02110-1301, USA.
#

use strict;
use warnings;
use FindBin;
use lib $FindBin::Bin;

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

my $defines;
my $preprocessor;
my $idlFilesList;
my $supplementalDependencyFile;
my $windowConstructorsFile;
my $workerGlobalScopeConstructorsFile;
my $dedicatedWorkerGlobalScopeConstructorsFile;
my $serviceWorkerGlobalScopeConstructorsFile;
my $supplementalMakefileDeps;

GetOptions('defines=s' => \$defines,
           'preprocessor=s' => \$preprocessor,
           'idlFilesList=s' => \$idlFilesList,
           'supplementalDependencyFile=s' => \$supplementalDependencyFile,
           'windowConstructorsFile=s' => \$windowConstructorsFile,
           'workerGlobalScopeConstructorsFile=s' => \$workerGlobalScopeConstructorsFile,
           'dedicatedWorkerGlobalScopeConstructorsFile=s' => \$dedicatedWorkerGlobalScopeConstructorsFile,
           'serviceWorkerGlobalScopeConstructorsFile=s' => \$serviceWorkerGlobalScopeConstructorsFile,
           'supplementalMakefileDeps=s' => \$supplementalMakefileDeps);

die('Must specify #define macros using --defines.') unless defined($defines);
die('Must specify an output file using --supplementalDependencyFile.') unless defined($supplementalDependencyFile);
die('Must specify an output file using --windowConstructorsFile.') unless defined($windowConstructorsFile);
die('Must specify an output file using --workerGlobalScopeConstructorsFile.') unless defined($workerGlobalScopeConstructorsFile);
die('Must specify an output file using --dedicatedWorkerGlobalScopeConstructorsFile.') unless defined($dedicatedWorkerGlobalScopeConstructorsFile);
die('Must specify an output file using --serviceWorkerGlobalScopeConstructorsFile.') unless defined($serviceWorkerGlobalScopeConstructorsFile);
die('Must specify the file listing all IDLs using --idlFilesList.') unless defined($idlFilesList);

$supplementalDependencyFile = CygwinPathIfNeeded($supplementalDependencyFile);
$windowConstructorsFile = CygwinPathIfNeeded($windowConstructorsFile);
$workerGlobalScopeConstructorsFile = CygwinPathIfNeeded($workerGlobalScopeConstructorsFile);
$dedicatedWorkerGlobalScopeConstructorsFile = CygwinPathIfNeeded($dedicatedWorkerGlobalScopeConstructorsFile);
$serviceWorkerGlobalScopeConstructorsFile = CygwinPathIfNeeded($serviceWorkerGlobalScopeConstructorsFile);
$supplementalMakefileDeps = CygwinPathIfNeeded($supplementalMakefileDeps);

open FH, "< $idlFilesList" or die "Cannot open $idlFilesList\n";
my @idlFilesIn = <FH>;
chomp(@idlFilesIn);
my @idlFiles = ();
foreach (@idlFilesIn) {
    push @idlFiles, CygwinPathIfNeeded($_);
}
close FH;

my %interfaceNameToIdlFile;
my %idlFileToInterfaceName;
my %supplementalDependencies;
my %supplementals;
my $windowConstructorsCode = "";
my $workerGlobalScopeConstructorsCode = "";
my $dedicatedWorkerGlobalScopeConstructorsCode = "";
my $serviceWorkerGlobalScopeConstructorsCode = "";

# Get rid of duplicates in idlFiles array.
my %idlFileHash = map { $_, 1 } @idlFiles;

# Populate $idlFileToInterfaceName and $interfaceNameToIdlFile.
foreach my $idlFile (sort keys %idlFileHash) {
    my $fullPath = Cwd::realpath($idlFile);
    my $interfaceName = fileparse(basename($idlFile), ".idl");
    $idlFileToInterfaceName{$fullPath} = $interfaceName;
    $interfaceNameToIdlFile{$interfaceName} = $fullPath;
}

# Parse all IDL files.
foreach my $idlFile (sort keys %idlFileHash) {
    my $fullPath = Cwd::realpath($idlFile);
    my $idlFileContents = getFileContents($fullPath);
    # Handle partial interfaces.
    my $partialInterfaceName = getPartialInterfaceNameFromIDL($idlFileContents);
    if ($partialInterfaceName) {
        $supplementalDependencies{$fullPath} = [$partialInterfaceName];
        next;
    }

    $supplementals{$fullPath} = [];

    # Skip if the IDL file does not contain an interface, a callback interface or an exception.
    # The IDL may contain a dictionary.
    next unless containsInterfaceOrExceptionFromIDL($idlFileContents);

    my $interfaceName = fileparse(basename($idlFile), ".idl");
    # Handle implements statements.
    my $implementedInterfaces = getImplementedInterfacesFromIDL($idlFileContents, $interfaceName);
    foreach my $implementedInterface (@{$implementedInterfaces}) {
        my $implementedIdlFile = $interfaceNameToIdlFile{$implementedInterface};
        die "Could not find a the IDL file where the following implemented interface is defined: $implementedInterface" unless $implementedIdlFile;
        if ($supplementalDependencies{$implementedIdlFile}) {
            push(@{$supplementalDependencies{$implementedIdlFile}}, $interfaceName);
        } else {
            $supplementalDependencies{$implementedIdlFile} = [$interfaceName];
        }
    }

    # For every interface that is exposed in a given ECMAScript global environment and:
    # - is a callback interface that has constants declared on it, or
    # - is a non-callback interface that is not declared with the [NoInterfaceObject] extended attribute, a corresponding
    #   property must exist on the ECMAScript environment's global object.
    # See https://heycam.github.io/webidl/#es-interfaces
    my $extendedAttributes = getInterfaceExtendedAttributesFromIDL($idlFileContents);
    unless ($extendedAttributes->{"NoInterfaceObject"}) {
        if (!isCallbackInterfaceFromIDL($idlFileContents) || interfaceHasConstantAttribute($idlFileContents)) {
            my $exposedAttribute = $extendedAttributes->{"Exposed"} || "Window";
            $exposedAttribute = substr($exposedAttribute, 1, -1) if substr($exposedAttribute, 0, 1) eq "(";
            my @globalContexts = split(",", $exposedAttribute);
            my ($attributeCode, $windowAliases) = GenerateConstructorAttributes($interfaceName, $extendedAttributes);
            foreach my $globalContext (@globalContexts) {
                if ($globalContext eq "Window") {
                    $windowConstructorsCode .= $attributeCode;
                } elsif ($globalContext eq "Worker") {
                    $workerGlobalScopeConstructorsCode .= $attributeCode;
                } elsif ($globalContext eq "DedicatedWorker") {
                    $dedicatedWorkerGlobalScopeConstructorsCode .= $attributeCode;
                } elsif ($globalContext eq "ServiceWorker") {
                    $serviceWorkerGlobalScopeConstructorsCode .= $attributeCode;
                } else {
                    die "Unsupported global context '$globalContext' used in [Exposed] at $idlFile";
                }
            }
            $windowConstructorsCode .= $windowAliases if $windowAliases;
        }
    }
}

# Generate partial interfaces for Constructors.
GeneratePartialInterface("DOMWindow", $windowConstructorsCode, $windowConstructorsFile);
GeneratePartialInterface("WorkerGlobalScope", $workerGlobalScopeConstructorsCode, $workerGlobalScopeConstructorsFile);
GeneratePartialInterface("DedicatedWorkerGlobalScope", $dedicatedWorkerGlobalScopeConstructorsCode, $dedicatedWorkerGlobalScopeConstructorsFile);
GeneratePartialInterface("ServiceWorkerGlobalScope", $serviceWorkerGlobalScopeConstructorsCode, $serviceWorkerGlobalScopeConstructorsFile);

# Resolves partial interfaces and implements dependencies.
foreach my $idlFile (sort keys %supplementalDependencies) {
    my $baseFiles = $supplementalDependencies{$idlFile};
    foreach my $baseFile (@{$baseFiles}) {
        my $targetIdlFile = $interfaceNameToIdlFile{$baseFile} or die "${baseFile}.idl not found, but it is supplemented by $idlFile";
        push(@{$supplementals{$targetIdlFile}}, $idlFile);
    }
    delete $supplementals{$idlFile};
}

# Outputs the dependency.
# The format of a supplemental dependency file:
#
# DOMWindow.idl P.idl Q.idl R.idl
# Document.idl S.idl
# Event.idl
# ...
#
# The above indicates that DOMWindow.idl is supplemented by P.idl, Q.idl and R.idl,
# Document.idl is supplemented by S.idl, and Event.idl is supplemented by no IDLs.
# The IDL that supplements another IDL (e.g. P.idl) never appears in the dependency file.
my $dependencies = "";
foreach my $idlFile (sort keys %supplementals) {
    $dependencies .= "$idlFile @{$supplementals{$idlFile}}\n";
}
WriteFileIfChanged($supplementalDependencyFile, $dependencies);

if ($supplementalMakefileDeps) {
    my $makefileDeps = "";
    foreach my $idlFile (sort keys %supplementals) {
        my $basename = $idlFileToInterfaceName{$idlFile};

        my @dependencies = map { basename($_) } @{$supplementals{$idlFile}};

        $makefileDeps .= "JS${basename}.h: @{dependencies}\n";
        $makefileDeps .= "DOM${basename}.h: @{dependencies}\n";
        $makefileDeps .= "WebDOM${basename}.h: @{dependencies}\n";
        foreach my $dependency (@dependencies) {
            $makefileDeps .= "${dependency}:\n";
        }
    }

    WriteFileIfChanged($supplementalMakefileDeps, $makefileDeps);
}

my $cygwinPathAdded;
sub CygwinPathIfNeeded
{
    my $path = shift;
    if ($path && $Config{osname} eq "cygwin") {
        if (not $cygwinPathAdded) {
            $ENV{PATH} = "$ENV{PATH}:/cygdrive/c/cygwin/bin";
            $cygwinPathAdded = 1; 
        }
        chomp($path = `cygpath -u '$path'`);
        $path =~ s/[\r\n]//;
    }
    return $path;
}

sub WriteFileIfChanged
{
    my $fileName = shift;
    my $contents = shift;

    if (-f $fileName) {
        open FH, "<", $fileName or die "Couldn't open $fileName: $!\n";
        my @lines = <FH>;
        my $oldContents = join "", @lines;
        close FH;
        return if $contents eq $oldContents;
    }
    open FH, ">", $fileName or die "Couldn't open $fileName: $!\n";
    print FH $contents;
    close FH;
}

sub GeneratePartialInterface
{
    my $interfaceName = shift;
    my $attributesCode = shift;
    my $destinationFile = shift;

    my $contents = "partial interface ${interfaceName} {\n$attributesCode};\n";
    WriteFileIfChanged($destinationFile, $contents);

    my $fullPath = Cwd::realpath($destinationFile);
    $supplementalDependencies{$fullPath} = [$interfaceName] if $interfaceNameToIdlFile{$interfaceName};
}

sub GenerateConstructorAttributes
{
    my $interfaceName = shift;
    my $extendedAttributes = shift;

    my $code = "    ";
    my @extendedAttributesList;
    foreach my $attributeName (sort keys %{$extendedAttributes}) {
      next unless ($attributeName eq "Conditional" || $attributeName eq "EnabledAtRuntime" || $attributeName eq "EnabledForWorld"
        || $attributeName eq "EnabledBySetting" || $attributeName eq "SecureContext" || $attributeName eq "PrivateIdentifier"
        || $attributeName eq "PublicIdentifier");
      my $extendedAttribute = $attributeName;
      $extendedAttribute .= "=" . $extendedAttributes->{$attributeName} unless $extendedAttributes->{$attributeName} eq "VALUE_IS_MISSING";
      push(@extendedAttributesList, $extendedAttribute);
    }
    $code .= "[" . join(', ', @extendedAttributesList) . "] " if @extendedAttributesList;

    my $originalInterfaceName = $interfaceName;
    $interfaceName = $extendedAttributes->{"InterfaceName"} if $extendedAttributes->{"InterfaceName"};
    $code .= "attribute " . $originalInterfaceName . "Constructor $interfaceName;\n";

    # In addition to the regular property, for every [NamedConstructor] extended attribute on an interface,
    # a corresponding property MUST exist on the ECMAScript global object.
    if ($extendedAttributes->{"NamedConstructor"}) {
        my $constructorName = $extendedAttributes->{"NamedConstructor"};
        $constructorName =~ s/\(.*//g; # Extract function name.
        $code .= "    ";
        $code .= "[" . join(', ', @extendedAttributesList) . "] " if @extendedAttributesList;
        $code .= "attribute " . $originalInterfaceName . "NamedConstructor $constructorName;\n";
    }
    
    my $windowAliasesCode;
    if ($extendedAttributes->{"LegacyWindowAlias"}) {
        my $attributeValue = $extendedAttributes->{"LegacyWindowAlias"};
        $attributeValue = substr($attributeValue, 1, -1) if substr($attributeValue, 0, 1) eq "(";
        my @windowAliases = split(",", $attributeValue);
        foreach my $windowAlias (@windowAliases) {
            $windowAliasesCode .= "    ";
            $windowAliasesCode .= "[" . join(', ', @extendedAttributesList) . "] " if @extendedAttributesList;
            $windowAliasesCode .= "attribute " . $originalInterfaceName . "Constructor $windowAlias; // Legacy Window alias.\n";
        }
    }
    
    return ($code, $windowAliasesCode);
}

sub getFileContents
{
    my $idlFile = shift;

    open FILE, "<", $idlFile;
    my @lines = <FILE>;
    close FILE;

    # Filter out preprocessor lines.
    @lines = grep(!/^\s*#/, @lines);

    return join('', @lines);
}

sub getPartialInterfaceNameFromIDL
{
    my $fileContents = shift;

    if ($fileContents =~ /partial\s+interface\s+(\w+)/gs) {
        return $1;
    }
}

# identifier-A implements identifier-B;
# http://www.w3.org/TR/WebIDL/#idl-implements-statements
sub getImplementedInterfacesFromIDL
{
    my $fileContents = shift;
    my $interfaceName = shift;

    my @implementedInterfaces = ();
    while ($fileContents =~ /^\s*(\w+)\s+implements\s+(\w+)\s*;/mg) {
        die "Identifier on the left of the 'implements' statement should be $interfaceName in $interfaceName.idl, but found $1" if $1 ne $interfaceName;
        push(@implementedInterfaces, $2);
    }
    return \@implementedInterfaces
}

sub isCallbackInterfaceFromIDL
{
    my $fileContents = shift;
    return ($fileContents =~ /callback\s+interface\s+\w+/gs);
}

sub containsInterfaceOrExceptionFromIDL
{
    my $fileContents = shift;

    return 1 if $fileContents =~ /\bcallback\s+interface\s+\w+/gs;
    return 1 if $fileContents =~ /\binterface\s+\w+/gs;
    return 1 if $fileContents =~ /\bexception\s+\w+/gs;
    return 0;
}

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

sub getInterfaceExtendedAttributesFromIDL
{
    my $fileContents = shift;

    my $extendedAttributes = {};

    # Remove comments from fileContents before processing.
    # FIX: Preference to use Regex::Common::comment, however it is not available on
    # all build systems.
    $fileContents =~ s/(?:(?:(?:\/\/)(?:[^\n]*)(?:\n))|(?:(?:\/\*)(?:(?:[^\*]+|\*(?!\/))*)(?:\*\/)))//g;

    if ($fileContents =~ /\[(.*)\]\s+(callback interface|interface|exception)\s+(\w+)/gs) {
        my @parts = split(m/,(?![^()]*\))/, $1);
        foreach my $part (@parts) {
            my @keyValue = split('=', $part);
            my $key = trim($keyValue[0]);
            next unless length($key);
            my $value = "VALUE_IS_MISSING";
            $value = trim($keyValue[1]) if @keyValue > 1;
            $extendedAttributes->{$key} = $value;
        }
    }

    return $extendedAttributes;
}

sub interfaceHasConstantAttribute
{
    my $fileContents = shift;

    return $fileContents =~ /\s+const[\s\w]+=\s+[\w]+;/gs;
}