package com.onetsoft.fastjsp;

import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.IdentityHashMap;
import java.util.List;
import java.util.Map;

/**
 * 布局管理
 * 每個布局下依次有頁面類組、組件類組、Action類組
 *
 * @see PageParamsImpl
 * @since 3.0
 */
final class LayoutManager {

    private Map componentsPool = new IdentityHashMap(4);      //key:pageClass , value:Component[]
    private Map actionManagersPool = new IdentityHashMap(4);  //key:pageClass , value:ActionsManager

    public LayoutManager() {
    }

    /**
     * 取得頁面組件管理
     *
     * @param pageClass
     * @return
     */
    public ComponentsManager getComponentsManager(Class pageClass) {
        Object o = componentsPool.get(pageClass);
        if (o == null) {
            synchronized (pageClass) {
                o = componentsPool.get(pageClass);
                if (o == null) {
                    o = loadComponents(pageClass);
                    synchronized (componentsPool) {
                        componentsPool.put(pageClass, o);
                    }
                }
            }
        }
        return new ComponentsManager((Class[]) o);
    }

    /**
     * 取得頁面action管理
     *
     * @param pageClass
     * @return
     */
    public ActionsManager getActionsManager(Class pageClass) {
        Object o = actionManagersPool.get(pageClass);
        if (o == null) {
            synchronized (pageClass) {
                o = actionManagersPool.get(pageClass);
                if (o == null) {
                    o = new ActionsManager(pageClass);
                    synchronized (actionManagersPool) {
                        actionManagersPool.put(pageClass, o);
                    }
                }
            }
        }
        return (ActionsManager) o;
    }


    private static Class[] loadComponents(Class pageClass) {
        try {
            List list = new ArrayList(4);
            retrieveComponents(getInitComponentInstance(pageClass), list);
            return (Class[]) list.toArray(new Class[list.size()]);
        } catch (InstantiationException e) {
            throw new ApplicationRuntimeException(e);
        } catch (IllegalAccessException e) {
            throw new ApplicationRuntimeException(e);
        } catch (NoSuchMethodException e) {
            throw new ApplicationRuntimeException(e);
        } catch (InvocationTargetException e) {
            throw new ApplicationRuntimeException(e);
        }
    }

    /**
     * 搜尋頁面所有組件類
     *
     * @param component
     * @throws IllegalAccessException
     * @throws InstantiationException
     */
    private static void retrieveComponents(AbstractComponent component, List list) throws NoSuchMethodException, IllegalAccessException, InstantiationException, InvocationTargetException {
        list.add(component.getClass());
        Class[] a = component.getComponents();
        if (a == null)
            return;
        for (int i = 0; i < a.length; i++) {
            retrieveComponents(getInitComponentInstance(a[i]), list);
        }
    }

    private static AbstractComponent getInitComponentInstance(Class pageClass) throws IllegalAccessException, InstantiationException {
        return (AbstractComponent) pageClass.newInstance();
    }


}