/*
 * Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT HOLDER OR 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.
 */

#pragma once

#include <AK/RefPtr.h>
#include <AK/String.h>
#include <LibCore/Account.h>
#include <LibCore/ElapsedTimer.h>
#include <LibCore/Notifier.h>
#include <LibCore/Object.h>

class Service final : public Core::Object {
    C_OBJECT(Service)

public:
    bool is_enabled() const;
    void activate();
    void did_exit(int exit_code);

    static Service* find_by_pid(pid_t);

    // FIXME: Port to Core::Property
    void save_to(JsonObject&);

private:
    Service(const Core::ConfigFile&, const StringView& name);

    void spawn(int socket_fd = -1);

    // Path to the executable. By default this is /bin/{m_name}.
    String m_executable_path;
    // Extra arguments, starting from argv[1], to pass when exec'ing.
    Vector<String> m_extra_arguments;
    // File path to open as stdio fds.
    String m_stdio_file_path;
    int m_priority { 1 };
    // Whether we should re-launch it if it exits.
    bool m_keep_alive { false };
    // Path to the socket to create and listen on on behalf of this service.
    String m_socket_path;
    // File system permissions for the socket.
    mode_t m_socket_permissions { 0 };
    // Whether we should accept connections on the socket and pass the accepted
    // (and not listening) socket to the service. This requires a multi-instance
    // service.
    bool m_accept_socket_connections { false };
    // Whether we should only spawn this service once somebody connects to the socket.
    bool m_lazy;
    // The name of the user we should run this service as.
    String m_user;
    // The working directory in which to spawn the service.
    String m_working_directory;
    // Boot modes to run this service in. By default, this is the graphical mode.
    Vector<String> m_boot_modes;
    // Whether several instances of this service can run at once.
    bool m_multi_instance { false };
    // Environment variables to pass to the service.
    Vector<String> m_environment;

    // The resolved user account to run this service as.
    Optional<Core::Account> m_account;

    // For single-instance services, PID of the running instance of this service.
    pid_t m_pid { -1 };
    // An open fd to the socket.
    int m_socket_fd { -1 };
    RefPtr<Core::Notifier> m_socket_notifier;

    // Timer since we last spawned the service.
    Core::ElapsedTimer m_run_timer;
    // How many times we have tried to restart this service, only counting those
    // times where it has exited unsuccessfully and too quickly.
    int m_restart_attempts { 0 };

    void setup_socket();
    void setup_notifier();
    void handle_socket_connection();
};