Launcher/LauncherAPI/src/main/java/pro/gravit/launcher/modules/LauncherModule.java

package pro.gravit.launcher.modules;

import java.util.HashMap;
import java.util.Map;

public abstract class LauncherModule {
    private LauncherModulesContext context;

    private Map<Class<? extends Event>, EventHandler> eventMap = new HashMap<>();
    protected LauncherModulesManager modulesManager;
    protected final LauncherModuleInfo moduleInfo;
    protected ModulesConfigManager modulesConfigManager;
    protected InitStatus initStatus = InitStatus.CREATED;

    protected LauncherModule() {
        moduleInfo = new LauncherModuleInfo("UnknownModule");
    }

    protected LauncherModule(LauncherModuleInfo info) {
        moduleInfo = info;
    }

    public LauncherModuleInfo getModuleInfo() {
        return moduleInfo;
    }


    /**
     * Module initialization status at the current time
     * CREATED - Module status immediately after loading
     * INIT - The state of the module during the execution of the method init()
     * FINISH - Status of the module after initialization
     */
    public enum InitStatus
    {
        CREATED(false),
        PRE_INIT_WAIT(true),
        PRE_INIT(false),
        INIT_WAIT(true),
        INIT(false),
        FINISH(true);

        InitStatus(boolean b) {
            isAvailable = b;
        }

        public boolean isAvailable() {
            return isAvailable;
        }

        private final boolean isAvailable;
    }
    @FunctionalInterface
    public interface EventHandler<T extends Event>
    {
        void event(T e);
    }
    public static class Event
    {
        public boolean isCancel() {
            return cancel;
        }

        public Event cancel() {
            this.cancel = true;
            return this;
        }

        protected boolean cancel = false;
    }

    public InitStatus getInitStatus() {
        return initStatus;
    }

    public LauncherModule setInitStatus(InitStatus initStatus) {
        this.initStatus = initStatus;
        return this;
    }

    /**
     * The internal method used by the ModuleManager
     * DO NOT TOUCH
     * @param context Private context
     */
    public void setContext(LauncherModulesContext context)
    {
        if(this.context != null) throw new IllegalStateException("Module already set context");
        this.context = context;
        this.modulesManager = context.getModulesManager();
        this.modulesConfigManager = context.getModulesConfigManager();
        this.setInitStatus(InitStatus.PRE_INIT_WAIT);
    }

    /**
     * This method is called before initializing all modules and resolving dependencies.
     * <b>You can</b>:
     * Use to Module Manager
     * Add custom modules not described in the manifest
     * Change information about your module or modules you control
     * <b>You can not</b>:
     * Use your dependencies
     * Use API Launcher, LaunchServer, ServerWrapper
     * Change the names of any modules
     */
    public void preInitAction() {
        //NOP
    }
    public LauncherModule preInit()
    {
        if(!initStatus.equals(InitStatus.PRE_INIT_WAIT)) throw new IllegalStateException("PreInit not allowed in current state");
        initStatus = InitStatus.PRE_INIT;
        preInitAction();
        initStatus = InitStatus.INIT_WAIT;
        return this;
    }

    /**
     * Basic module initialization method
     * <b>You can</b>:
     * Subscribe to events
     * Use your dependencies
     * Use provided initContext
     * Receive modules and access the module’s internal methods
     * <b>You can not</b>:
     * Modify module description, dependencies
     * Add modules
     * Read configuration
     * @param initContext <tr>null</tr> on module initialization during boot or startup
     * Not <tr>null</tr> during module initialization while running
     */
    public abstract void init(LauncherInitContext initContext);


    /**
     * Registers an event handler for the current module
     * @param handle your event handler
     * @param tClass event class
     * @param <T> event type
     * @return true if adding a handler was successful
     */
    protected <T extends Event> boolean registerEvent(EventHandler<T> handle, Class<T> tClass)
    {
        eventMap.put(tClass, handle);
        return true;
    }

    /**
     * Call the handler of the current module
     * @param event event handled
     * @param <T> event type
     */
    @SuppressWarnings("unchecked")
    public final <T extends Event> void callEvent(T event)
    {
        Class<? extends Event> tClass = event.getClass();
        for(Map.Entry<Class<? extends Event>, EventHandler> e : eventMap.entrySet())
        {

            if(e.getKey().isAssignableFrom(tClass))
            {
                e.getValue().event(event);
                if(event.isCancel()) return;
            }
        }
    }
}