/* SaveFormBindingImpl.java

	Purpose:
		
	Description:
		
	History:
		Aug 9, 2011 6:30:34 PM, Created by henrichen

Copyright (C) 2011 Potix Corporation. All Rights Reserved.
*/

package org.zkoss.bind.impl;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import javassist.util.proxy.MethodHandler;
import javassist.util.proxy.Proxy;
import javassist.util.proxy.ProxyFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.zkoss.bind.BindContext;
import org.zkoss.bind.Binder;
import org.zkoss.bind.Form;
import org.zkoss.bind.FormLegacy;
import org.zkoss.bind.FormLegacyExt;
import org.zkoss.bind.FormStatus;
import org.zkoss.bind.Property;
import org.zkoss.bind.ValidationContext;
import org.zkoss.bind.Validator;
import org.zkoss.bind.proxy.FormProxyHandler;
import org.zkoss.bind.sys.BindEvaluatorX;
import org.zkoss.bind.sys.BinderCtrl;
import org.zkoss.bind.sys.ConditionType;
import org.zkoss.bind.sys.SaveFormBinding;
import org.zkoss.bind.sys.debugger.BindingExecutionInfoCollector;
import org.zkoss.bind.sys.debugger.impl.info.SaveInfo;
import org.zkoss.bind.sys.debugger.impl.info.ValidationInfo;
import org.zkoss.lang.reflect.Fields;
import org.zkoss.xel.ExpressionX;
import org.zkoss.xel.ValueReference;
import org.zkoss.zel.PropertyNotFoundException;
import org.zkoss.zk.ui.Component;
import org.zkoss.zk.ui.UiException;

/**
 * Implementation of {@link SaveFormBinding}.
 * @author henrichen
 * @since 6.0.0
 */
public class SaveFormBindingImpl extends FormBindingImpl implements SaveFormBinding {
	private static final Logger log = LoggerFactory.getLogger(SaveFormBindingImpl.class);
	private static final long serialVersionUID = 1463169907348730644L;
	private final ExpressionX _validator;
	private final Map<String, Object> _validatorArgs;

	private static final String VALUEREF = "$VALUEREF$";

	public SaveFormBindingImpl(Binder binder, Component comp, String formId, String saveExpr,
			ConditionType conditionType, String command, Map<String, Object> bindingArgs, String validatorExpr,
			Map<String, Object> validatorArgs) {
		super(binder, comp, formId, saveExpr, conditionType, command, bindingArgs);
		final BindEvaluatorX eval = binder.getEvaluatorX();
		_validator = validatorExpr == null ? null : parseValidator(eval, validatorExpr);
		_validatorArgs = validatorArgs;

		Form form = getFormBean();
		if (form instanceof FormLegacy)
			return;
		// force to init Form for validation
		getFormBean(BindContextUtil.newBindContext(binder, this, false, null, getComponent(), null));

	}

	public Map<String, Object> getValidatorArgs() {
		return _validatorArgs;
	}

	protected boolean ignoreTracker() {
		return true;
	}

	private ExpressionX parseValidator(BindEvaluatorX eval, String validatorExpr) {
		//		final BindContext ctx = BindContextUtil.newBindContext(getBinder(), this, false, null, getComponent(), null);
		//		ctx.setAttribute(BinderImpl.IGNORE_TRACKER, Boolean.TRUE);//ignore tracker when doing el, we don't need to trace validator
		//don't provide a bindcontext when pare expression of validator with this binding,
		//do so, the tracker will not also tracking the validator dependence with this binding.
		return eval.parseExpressionX(null, validatorExpr, Object.class);
	}

	public Validator getValidator() {
		if (_validator == null)
			return null;

		//		final BindContext ctx = BindContextUtil.newBindContext(getBinder(), this, false, null, getComponent(), null);
		//		ctx.setAttribute(BinderImpl.IGNORE_TRACKER, Boolean.TRUE);//ignore tracker when doing el, we don't need to trace validator		
		final BindEvaluatorX eval = getBinder().getEvaluatorX();
		Object obj = eval.getValue(/*ctx*/null, getComponent(), _validator);

		if (obj instanceof Validator) {
			return (Validator) obj;
		} else if (obj instanceof String) {
			return getBinder().getValidator((String) obj); //binder will throw exception if not found
		} else {
			throw new ClassCastException(
					"result of expression '" + _validator.getExpressionString() + "' is not a Validator, is " + obj);
		}
	}

	public Form getFormBean(BindContext ctx) {
		Form form = getFormBean();
		if (form == null) {
			final Binder binder = getBinder();
			final BindEvaluatorX eval = binder.getEvaluatorX();
			final Component comp = getComponent();

			final Object bean = eval.getValue(ctx, comp, _accessInfo.getProperty());
			form = initFormBean(bean, (Class<Object>) (bean == null ? eval.getType(ctx, comp, _accessInfo.getProperty())
					: bean.getClass()), ctx);
		}
		return form;
	}

	public void save(BindContext ctx) {
		final Binder binder = getBinder();
		final Component comp = getComponent(); //ctx.getComponent();
		final Form form = getFormBean(ctx);

		BindingExecutionInfoCollector collector = ((BinderCtrl) getBinder()).getBindingExecutionInfoCollector();
		
		//update form field into backing bean
		if (form instanceof FormLegacy) {
			if (form instanceof FormLegacyExt) {
				final BindEvaluatorX eval = binder.getEvaluatorX();
				for (String field : ((FormLegacyExt) form).getSaveFieldNames()) {
					final ExpressionX expr = getFieldExpression(eval, field);
					if (expr != null) {
						//ZK-911. Load from Form bean via expression(so will use form's AccessFieldName)
						final ExpressionX formExpr = getFormExpression(eval, field);
						final Object value = eval.getValue(null, comp, formExpr); //form.getField(field);
						eval.setValue(ctx, comp, expr, value);
					}
					//TODO should we clear form dirty and notify formStatus?
				}
			}
		} else {
			FormStatus formStatus = form.getFormStatus();
			if (formStatus.isDirty()) {
				Object origin = null;
				try {
					// Fix Load_save_formTest.java, if @save is different than @load target.
					if (_accessInfo.getProperty().getExpressionString().contains(".")) {
						try {
							ValueReference valueReference = getValueReference(
									ctx);
							Object target = Fields.get(valueReference.getBase(),
									(String) valueReference.getProperty());

							Object formStatusOrigin = formStatus.getOrigin();
							if (formStatusOrigin != null && !formStatusOrigin.equals(target)) {
								MethodHandler handler = ProxyFactory.getHandler(
										(Proxy) formStatusOrigin);
								if (handler instanceof FormProxyHandler) {
									Field originField = handler.getClass().getSuperclass()
											.getDeclaredField("_origin");
									// change origin here
									originField.setAccessible(true);
									origin = originField.get(handler);
									originField.set(handler, target);
									originField.setAccessible(false);
								}
							}
						} catch (Throwable t) {
							// ignore
						}
					}
					formStatus.submit(ctx);
				} finally {
					// if origin is not null, we should set it back to the form bean.
					if (origin != null) {
						try {
							Object formStatusOrigin = formStatus.getOrigin();
							MethodHandler handler = ProxyFactory.getHandler((Proxy) formStatusOrigin);
							Field originField = handler.getClass().getSuperclass().getDeclaredField("_origin");
							// change origin back here
							originField.setAccessible(true);
							originField.set(handler, origin);
							originField.setAccessible(false);
						} catch (Throwable t) {
							throw new RuntimeException(t);
						}
					}
				}
			}
			
			binder.notifyChange(formStatus, "."); //notify change of fxStatus and fxStatus.*
		}
		if (collector != null) {
			collector.addInfo(new SaveInfo(SaveInfo.FORM_SAVE, comp, getConditionString(ctx), getFormId(),
					getPropertyString(), form, getArgs(), null));
		}
	}

	private String getConditionString(BindContext ctx) {
		StringBuilder condition = new StringBuilder();
		if (getConditionType() == ConditionType.BEFORE_COMMAND) {
			condition.append("before = '").append(getCommandName()).append("'");
		} else if (getConditionType() == ConditionType.AFTER_COMMAND) {
			condition.append("after = '").append(getCommandName()).append("'");
		} else {
			condition.append(ctx.getTriggerEvent() == null ? "" : "event = " + ctx.getTriggerEvent().getName());
		}
		return condition.length() == 0 ? null : condition.toString();
	}

	//--SaveBinding--//
	public Property getValidate(BindContext ctx) {
		//we should not check this binding need to validate or not here, 
		//since other validator may want to know the value of porperty of this binding, so just provide it 
		final Binder binder = getBinder();
		final BindEvaluatorX eval = binder.getEvaluatorX();
		final Component comp = getComponent(); //ctx.getComponent();
		final Form form = getFormBean(ctx);

		final ExpressionX expr = getBaseExpression(eval);
		if (expr != null) {
			final Object base = eval.getValue(ctx, comp, expr);
			return new PropertyImpl(base, ".", form);
		}
		return null;
	}

	//--SaveFormBinding--//
	public Set<Property> getValidates(BindContext ctx) {
		final Set<Property> properties = new HashSet<Property>(2);
		//we should not check this binding need to validate or not here, 
		//since other validator may want to know the value of porperty of this binding, so just provide it 
		final Binder binder = getBinder();
		final BindEvaluatorX eval = binder.getEvaluatorX();
		final Component comp = getComponent(); //ctx.getComponent();
		final Form form = getFormBean(ctx);

		//remember base and form field
		if (form instanceof Form) {
			for (String field : ((BinderCtrl) binder).getSaveFormFieldNames(form)) {
				if (field.indexOf("[$INDEX$]") != -1) // skip collection field
					continue;
				final ExpressionX expr = getFieldExpression(eval, field);
				if (expr != null) {
					//ZK-911. Load from Form bean via expression(so will use form's AccessFieldName)
					final ExpressionX formExpr = getFormExpression(eval, field);
					final Object value = eval.getValue(null, comp, formExpr); //form.getField(field);
					ValueReference valref = null;
					try {
						valref = eval.getValueReference(ctx, comp, expr);
					} catch (PropertyNotFoundException e) {
						//ignore PropertyNotFoundException, might be new added expression
					}
					if (valref == null)
						log.debug("value reference not found by expression [" + expr.getExpressionString()
								+ "], check if you are trying to save to a variable only expression");
					else
						properties.add(new PropertyImpl(valref.getBase(), (String) valref.getProperty(), value));
				}
			}
		}
		return properties;
	}

	public boolean hasValidator() {
		return _validator != null;
	}

	public String getValidatorExpressionString() {
		return _validator == null ? null : BindEvaluatorXUtil.getExpressionString(_validator);
	}

	public void validate(ValidationContext vctx) {
		Validator validator = getValidator();
		if (validator == null) {
			throw new NullPointerException("cannot find validator for " + this);
		}
		validator.validate(vctx);

		BindingExecutionInfoCollector collector = ((BinderCtrl) getBinder()).getBindingExecutionInfoCollector();
		if (collector != null) {
			collector.addInfo(new ValidationInfo(ValidationInfo.PROP, getComponent(), getValidatorExpressionString(),
					validator.toString(), Boolean.valueOf(vctx.isValid()),
					((BindContextImpl) vctx.getBindContext()).getValidatorArgs(), null));
		}
		//		//collect notify change
		//		collectNotifyChange(validator,vctx);
	}

	//	private void collectNotifyChange(Validator validator, ValidationContext vctx) {
	//		//collect notify change
	//		ValueReference ref = getValueReference(vctx.getBindContext());
	//		//for special case that a form bind to vm directly, ex @form(save=vm after 'cmd1'), ref will be null
	//		if(ref!=null){
	//			BindELContext.addNotifys(getValidatorMethod(validator.getClass()), ref.getBase(), null, null, vctx.getBindContext());
	//		}else{
	//			final BindEvaluatorX eval = getBinder().getEvaluatorX();
	//			final ExpressionX expr = getBaseExpression(eval);
	//			if (expr != null) {
	//				final Object base = eval.getValue(vctx.getBindContext(), getComponent(), expr);
	//				BindELContext.addNotifys(getValidatorMethod(validator.getClass()), base, null, null, vctx.getBindContext());
	//			}			
	//		}
	//	}

	//get and cache value reference of this binding
	private ValueReference getValueReference(BindContext ctx) {
		ValueReference valref = (ValueReference) getAttribute(ctx, VALUEREF);
		if (valref == null) {
			final Component comp = getComponent(); //ctx.getComponent();
			final BindEvaluatorX eval = getBinder().getEvaluatorX();
			valref = eval.getValueReference(ctx, comp, _accessInfo.getProperty());
			if (valref == null) {
				throw new UiException(
						"value reference not found by expression [" + _accessInfo.getProperty().getExpressionString()
								+ "], check if you are trying to save to a variable only expression");
			}
			setAttribute(ctx, VALUEREF, valref);
		}
		return valref;
	}

	private Method getValidatorMethod(Class<? extends Validator> cls) {
		try {
			return cls.getMethod("validate", new Class[] { ValidationContext.class });
		} catch (NoSuchMethodException e) {
			//ignore
		}
		return null; //shall never come here
	}
}
