/*
 * Copyright (c) 2020-2021, Andreas Kling <andreas@ladybird.org>
 * Copyright (c) 2021-2023, Linus Groh <linusg@serenityos.org>
 * Copyright (c) 2021, Luke Wilde <lukew@serenityos.org>
 * Copyright (c) 2022, Ali Mohammad Pur <mpfard@serenityos.org>
 * Copyright (c) 2023, Andrew Kaster <akaster@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include "IDLGenerators.h"
#include "Namespaces.h"
#include <AK/Debug.h>
#include <AK/LexicalPath.h>
#include <LibCore/ArgsParser.h>
#include <LibCore/File.h>
#include <LibIDL/IDLParser.h>
#include <LibIDL/Types.h>

template<typename GeneratorFunction>
static ErrorOr<void> write_if_changed(GeneratorFunction generator_function, IDL::Interface const& interface, StringView file_path)
{
    StringBuilder output_builder;
    generator_function(interface, output_builder);

    auto current_file_or_error = Core::File::open(file_path, Core::File::OpenMode::Read);
    if (current_file_or_error.is_error() && current_file_or_error.error().code() != ENOENT)
        return current_file_or_error.release_error();

    ByteBuffer current_contents;
    if (!current_file_or_error.is_error())
        current_contents = TRY(current_file_or_error.value()->read_until_eof());
    // Only write to disk if contents have changed
    if (current_contents != output_builder.string_view().bytes()) {
        auto output_file = TRY(Core::File::open(file_path, Core::File::OpenMode::Write | Core::File::OpenMode::Truncate));
        TRY(output_file->write_until_depleted(output_builder.string_view().bytes()));
    }

    return {};
}

static ErrorOr<void> generate_depfile(StringView depfile_path, ReadonlySpan<ByteString> dependency_paths, ReadonlySpan<ByteString> output_files)
{
    auto depfile = TRY(Core::File::open_file_or_standard_stream(depfile_path, Core::File::OpenMode::Write));

    StringBuilder depfile_builder;
    bool first_output = true;
    for (auto const& s : output_files) {
        if (!first_output)
            depfile_builder.append(' ');

        depfile_builder.append(s);
        first_output = false;
    }
    depfile_builder.append(':');
    for (auto const& path : dependency_paths) {
        depfile_builder.append(" \\\n "sv);
        depfile_builder.append(path);
    }
    depfile_builder.append('\n');
    return depfile->write_until_depleted(depfile_builder.string_view().bytes());
}

ErrorOr<int> ladybird_main(Main::Arguments arguments)
{
    Core::ArgsParser args_parser;
    StringView path;
    Vector<ByteString> import_base_paths;
    StringView output_path = "-"sv;
    StringView depfile_path;
    StringView depfile_prefix;

    args_parser.add_option(Core::ArgsParser::Option {
        .argument_mode = Core::ArgsParser::OptionArgumentMode::Required,
        .help_string = "Add a header search path passed to the compiler",
        .long_name = "header-include-path",
        .short_name = 'i',
        .value_name = "path",
        .accept_value = [&](StringView s) {
            IDL::g_header_search_paths.append(s);
            return true;
        },
    });
    args_parser.add_option(output_path, "Path to output generated files into", "output-path", 'o', "output-path");
    args_parser.add_option(depfile_path, "Path to write dependency file to", "depfile", 'd', "depfile-path");
    args_parser.add_option(depfile_prefix, "Prefix to prepend to relative paths in dependency file", "depfile-prefix", 'p', "depfile-prefix");
    args_parser.add_positional_argument(path, "IDL file", "idl-file");
    args_parser.add_positional_argument(import_base_paths, "Import base path", "import-base-path", Core::ArgsParser::Required::No);
    args_parser.parse(arguments);

    auto idl_file = TRY(Core::File::open(path, Core::File::OpenMode::Read));

    LexicalPath lexical_path(path);
    auto& namespace_ = lexical_path.parts_view().at(lexical_path.parts_view().size() - 2);

    auto data = TRY(idl_file->read_until_eof());

    if (import_base_paths.is_empty())
        import_base_paths.append(lexical_path.dirname());

    IDL::Context context;

    auto module = IDL::Parser::parse(path, data, move(import_base_paths), context);
    VERIFY(module.interface.has_value());
    auto& interface = module.interface.value();

    // If the interface name is the same as its namespace, qualify the name in the generated code.
    // e.g. Selection::Selection
    if (IDL::libweb_interface_namespaces.span().contains_slow(namespace_)) {
        StringBuilder builder;
        builder.append(namespace_);
        builder.append("::"sv);
        builder.append(interface.implemented_name);
        interface.fully_qualified_name = builder.to_byte_string();
    } else {
        interface.fully_qualified_name = interface.implemented_name;
    }

    if constexpr (BINDINGS_GENERATOR_DEBUG) {
        interface.dump();
    }

    auto path_prefix = LexicalPath::join(output_path, lexical_path.basename(LexicalPath::StripExtension::Yes));
    auto header_path = ByteString::formatted("{}.h", path_prefix);
    auto implementation_path = ByteString::formatted("{}.cpp", path_prefix);

    TRY(write_if_changed(&IDL::generate_header, interface, header_path));
    TRY(write_if_changed(&IDL::generate_implementation, interface, implementation_path));

    if (!depfile_path.is_empty()) {
        TRY(generate_depfile(depfile_path, module.imported_files, { { header_path, implementation_path } }));
    }
    return 0;
}