/*
 * Copyright (c) 2023, Andrew Kaster <akaster@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include "HelperProcess.h"
#include <LibCore/Environment.h>

ErrorOr<NonnullRefPtr<WebView::WebContentClient>> launch_web_content_process(
    WebView::ViewImplementation& view,
    ReadonlySpan<ByteString> candidate_web_content_paths,
    Ladybird::WebContentOptions const& web_content_options)
{
    int socket_fds[2] {};
    TRY(Core::System::socketpair(AF_LOCAL, SOCK_STREAM, 0, socket_fds));

    int ui_fd = socket_fds[0];
    int wc_fd = socket_fds[1];

    int fd_passing_socket_fds[2] {};
    TRY(Core::System::socketpair(AF_LOCAL, SOCK_STREAM, 0, fd_passing_socket_fds));

    int ui_fd_passing_fd = fd_passing_socket_fds[0];
    int wc_fd_passing_fd = fd_passing_socket_fds[1];

    if (auto child_pid = TRY(Core::System::fork()); child_pid == 0) {
        TRY(Core::System::close(ui_fd_passing_fd));
        TRY(Core::System::close(ui_fd));

        auto takeover_string = TRY(String::formatted("WebContent:{}", wc_fd));
        TRY(Core::Environment::set("SOCKET_TAKEOVER"sv, takeover_string, Core::Environment::Overwrite::Yes));

        auto webcontent_fd_passing_socket_string = TRY(String::number(wc_fd_passing_fd));

        ErrorOr<void> result;
        for (auto const& path : candidate_web_content_paths) {
            constexpr auto callgrind_prefix_length = 3;

            if (Core::System::access(path, X_OK).is_error())
                continue;

            auto arguments = Vector {
                "valgrind"sv,
                "--tool=callgrind"sv,
                "--instr-atstart=no"sv,
                path.view(),
                "--command-line"sv,
                web_content_options.command_line,
                "--executable-path"sv,
                web_content_options.executable_path,
                "--webcontent-fd-passing-socket"sv,
                webcontent_fd_passing_socket_string
            };
            if (web_content_options.enable_callgrind_profiling == Ladybird::EnableCallgrindProfiling::No)
                arguments.remove(0, callgrind_prefix_length);
            if (web_content_options.is_layout_test_mode == Ladybird::IsLayoutTestMode::Yes)
                arguments.append("--layout-test-mode"sv);
            if (web_content_options.use_lagom_networking == Ladybird::UseLagomNetworking::Yes)
                arguments.append("--use-lagom-networking"sv);
            if (web_content_options.enable_gpu_painting == Ladybird::EnableGPUPainting::Yes)
                arguments.append("--use-gpu-painting"sv);
            if (web_content_options.wait_for_debugger == Ladybird::WaitForDebugger::Yes)
                arguments.append("--wait-for-debugger"sv);
            Vector<ByteString> certificate_args;
            for (auto const& certificate : web_content_options.certificates) {
                certificate_args.append(ByteString::formatted("--certificate={}", certificate));
                arguments.append(certificate_args.last().view());
            }

            result = Core::System::exec(arguments[0], arguments.span(), Core::System::SearchInPath::Yes);
            if (!result.is_error())
                break;
        }

        if (result.is_error())
            warnln("Could not launch any of {}: {}", candidate_web_content_paths, result.error());
        VERIFY_NOT_REACHED();
    }

    TRY(Core::System::close(wc_fd_passing_fd));
    TRY(Core::System::close(wc_fd));

    auto socket = TRY(Core::LocalSocket::adopt_fd(ui_fd));
    TRY(socket->set_blocking(true));

    auto new_client = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) WebView::WebContentClient(move(socket), view)));
    new_client->set_fd_passing_socket(TRY(Core::LocalSocket::adopt_fd(ui_fd_passing_fd)));

    if (web_content_options.enable_callgrind_profiling == Ladybird::EnableCallgrindProfiling::Yes) {
        dbgln();
        dbgln("\033[1;45mLaunched WebContent process under callgrind!\033[0m");
        dbgln("\033[100mRun `\033[4mcallgrind_control -i on\033[24m` to start instrumentation and `\033[4mcallgrind_control -i off\033[24m` stop it again.\033[0m");
        dbgln();
    }

    return new_client;
}

template<typename Client>
ErrorOr<NonnullRefPtr<Client>> launch_generic_server_process(ReadonlySpan<ByteString> candidate_server_paths, StringView serenity_resource_root, Vector<ByteString> const& certificates, StringView server_name)
{
    int socket_fds[2] {};
    TRY(Core::System::socketpair(AF_LOCAL, SOCK_STREAM, 0, socket_fds));

    int ui_fd = socket_fds[0];
    int server_fd = socket_fds[1];

    int fd_passing_socket_fds[2] {};
    TRY(Core::System::socketpair(AF_LOCAL, SOCK_STREAM, 0, fd_passing_socket_fds));

    int ui_fd_passing_fd = fd_passing_socket_fds[0];
    int server_fd_passing_fd = fd_passing_socket_fds[1];

    if (auto child_pid = TRY(Core::System::fork()); child_pid == 0) {
        TRY(Core::System::close(ui_fd));
        TRY(Core::System::close(ui_fd_passing_fd));

        auto takeover_string = TRY(String::formatted("{}:{}", server_name, server_fd));
        TRY(Core::Environment::set("SOCKET_TAKEOVER"sv, takeover_string, Core::Environment::Overwrite::Yes));

        auto fd_passing_socket_string = TRY(String::number(server_fd_passing_fd));

        ErrorOr<void> result;
        for (auto const& path : candidate_server_paths) {

            if (Core::System::access(path, X_OK).is_error())
                continue;

            auto arguments = Vector<StringView, 5> {
                path.view(),
                "--fd-passing-socket"sv,
                fd_passing_socket_string,
            };
            if (!serenity_resource_root.is_empty()) {
                arguments.append("--serenity-resource-root"sv);
                arguments.append(serenity_resource_root);
            }
            Vector<ByteString> certificate_args;
            for (auto const& certificate : certificates) {
                certificate_args.append(ByteString::formatted("--certificate={}", certificate));
                arguments.append(certificate_args.last().view());
            }

            result = Core::System::exec(arguments[0], arguments.span(), Core::System::SearchInPath::Yes);
            if (!result.is_error())
                break;
        }

        if (result.is_error())
            warnln("Could not launch any of {}: {}", candidate_server_paths, result.error());
        VERIFY_NOT_REACHED();
    }

    TRY(Core::System::close(server_fd));
    TRY(Core::System::close(server_fd_passing_fd));

    auto socket = TRY(Core::LocalSocket::adopt_fd(ui_fd));
    TRY(socket->set_blocking(true));

    auto new_client = TRY(try_make_ref_counted<Client>(move(socket)));
    new_client->set_fd_passing_socket(TRY(Core::LocalSocket::adopt_fd(ui_fd_passing_fd)));

    return new_client;
}

ErrorOr<NonnullRefPtr<ImageDecoderClient::Client>> launch_image_decoder_process(ReadonlySpan<ByteString> candidate_image_decoder_paths)
{
    return launch_generic_server_process<ImageDecoderClient::Client>(candidate_image_decoder_paths, ""sv, {}, "ImageDecoder"sv);
}

ErrorOr<NonnullRefPtr<Web::HTML::WebWorkerClient>> launch_web_worker_process(ReadonlySpan<ByteString> candidate_web_worker_paths, Vector<ByteString> const& certificates)
{
    return launch_generic_server_process<Web::HTML::WebWorkerClient>(candidate_web_worker_paths, ""sv, certificates, "WebWorker"sv);
}

ErrorOr<NonnullRefPtr<Protocol::RequestClient>> launch_request_server_process(ReadonlySpan<ByteString> candidate_request_server_paths, StringView serenity_resource_root, Vector<ByteString> const& certificates)
{
    return launch_generic_server_process<Protocol::RequestClient>(candidate_request_server_paths, serenity_resource_root, certificates, "RequestServer"sv);
}