package com.burtbeckwith.grails.delayds

import java.lang.reflect.Field
import java.lang.reflect.InvocationHandler
import java.lang.reflect.Method
import java.lang.reflect.Proxy

import org.codehaus.groovy.grails.orm.hibernate.ConfigurableLocalSessionFactoryBean
import org.hibernate.SessionFactory
import org.springframework.util.ReflectionUtils

class DelayedSessionFactoryBean extends ConfigurableLocalSessionFactoryBean {

	private boolean _initialized
	private SessionFactory _realSessionFactory

	@Override
	void afterPropertiesSet() {
		// do nothing for now, lazy init in createDelayedSessionFactory()
	}

	@Override
	SessionFactory getObject() {

		def invoke = { proxy, Method method, Object[] args ->
			initialize()
			return method.invoke(_realSessionFactory, args)
		}

		return Proxy.newProxyInstance(SessionFactory.classLoader,
				[SessionFactory] as Class[], [invoke: invoke] as InvocationHandler)
	}

	private synchronized void initialize() {
		if (_initialized) {
			return
		}

		_realSessionFactory = wrapSessionFactoryIfNecessary(buildSessionFactory())

		Field field = ReflectionUtils.findField(getClass(), "sessionFactory")
		field.accessible = true
		field.set(this, _realSessionFactory)

		afterSessionFactoryCreation()

		_initialized = true
	}
}