module ecs.system;

import ecs.entity;
import ecs.manager;

/************************************************************************************************************************
*System contain data required to proper glue EntityManager with Systems.
*/
struct System
{
    /************************************************************************************************************************
    *Check if system is enabled.
    */
    export bool enabled()
    {
        return m_enabled;
    }

    /************************************************************************************************************************
    *Enable system. If actually it is enabled function do nothing.
    */
    export void enable()
    {
        if (!m_enabled && m_enable)
            m_enable(m_system_pointer);
        m_enabled = true;
    }

    /************************************************************************************************************************
    *Disable system. If actually it is disabled function do nothing.
    */
    export void disable()
    {
        if (m_enabled && m_disable)
            m_disable(m_system_pointer);
        m_enabled = false;
    }

    /************************************************************************************************************************
    *Get system priority.
    */
    export int priority()
    {
        return m_priority;
    }

package:

    ///should system update and catch events?
    bool m_enabled = false;
    ///system priority
    int m_priority;
    ///pointer to system implementation
    void* m_system_pointer;

    ///system name
    const (char)[] name;

    ///required components
    ushort[] m_components;
    ///absen components
    ushort[] m_absen_components;
    ///optional components
    ushort[] m_optional_components;

    //void function(ref EntityManager.CallData data, void* entity) update;
    void* m_update; ///workaroud for DMD bug with upper line

    void function(void* system_pointer) m_enable;
    void function(void* system_pointer) m_disable;

    void function(void* system_pointer) m_create;
    void function(void* system_pointer) m_destroy;

    void function(void* system_pointer) m_begin;
    void function(void* system_pointer) m_end;
}