/* BindELResolver.java

	Purpose:
		
	Description:
		
	History:
		Aug 10, 2011 4:31:51 PM, Created by henrichen

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

package org.zkoss.bind.xel.zel;

import java.lang.reflect.Method;
import java.util.Set;

import org.zkoss.bind.BindContext;
import org.zkoss.bind.Binder;
import org.zkoss.bind.Form;
import org.zkoss.bind.impl.BinderImpl;
import org.zkoss.bind.impl.LoadFormBindingImpl;
import org.zkoss.bind.impl.Path;
import org.zkoss.bind.impl.SimpleBindXelContext;
import org.zkoss.bind.proxy.FormProxyObject;
import org.zkoss.bind.sys.BinderCtrl;
import org.zkoss.bind.sys.Binding;
import org.zkoss.bind.sys.LoadBinding;
import org.zkoss.bind.sys.ReferenceBinding;
import org.zkoss.bind.sys.SaveBinding;
import org.zkoss.bind.tracker.impl.TrackerImpl;
import org.zkoss.lang.Objects;
import org.zkoss.xel.XelContext;
import org.zkoss.xel.zel.XelELResolver;
import org.zkoss.zel.CompositeELResolver;
import org.zkoss.zel.ELContext;
import org.zkoss.zel.ELException;
import org.zkoss.zel.ELResolver;
import org.zkoss.zel.MethodInfo;
import org.zkoss.zel.MethodNotFoundException;
import org.zkoss.zel.PropertyNotFoundException;
import org.zkoss.zel.PropertyNotWritableException;
import org.zkoss.zel.impl.lang.EvaluationContext;
import org.zkoss.zel.impl.parser.AstMethodParameters;
import org.zkoss.zk.ui.Component;

/**
 * ELResolver for Binding; handle Form bean.
 * @author henrichen
 * @since 6.0.0
 */
public class BindELResolver extends XelELResolver {
	protected CompositeELResolver _resolver;
	protected PathELResolver _pathResolver;
	private ImplicitObjectELResolver _implicitResolver;

	public BindELResolver(XelContext ctx) {
		super(ctx);
		init();
	}

	protected void init() {
		_resolver = new CompositeELResolver();
		if (_pathResolver == null)
			_resolver.add(_pathResolver = new PathELResolver()); //must be the first
		else
			_resolver.add(_pathResolver);

		_resolver.add(new ListModelELResolver());
		_resolver.add(new TreeModelELResolver());
		_resolver.add(new ValidationMessagesELResolver());
		_resolver.add(getImplicitResolver()); //ZK-1032 Able to wire Event to command method
		_resolver.add(new DynamicPropertiedELResolver()); //ZK-1472 Bind Include Arg
		_resolver.add(getSuperELResolver());
	}

	protected ELResolver getSuperELResolver() {
		return super.getELResolver();
	}

	protected ELResolver getELResolver() {
		return _resolver;
	}

	protected ImplicitObjectELResolver getImplicitResolver() {
		if (_implicitResolver == null)
			_implicitResolver = new ImplicitObjectELResolver();
		return _implicitResolver;
	}

	//ELResolver//
	public Object getValue(ELContext ctx, Object base, Object property) throws PropertyNotFoundException, ELException {
		Object value = null;
		if (base == null) {
			if (_pathResolver == null) {
				_pathResolver = new PathELResolver(); // init
			}
			_pathResolver.getValue(ctx, base, property);

			if (value == null && _ctx instanceof SimpleBindXelContext) {
				SimpleBindXelContext bctxt = (SimpleBindXelContext) _ctx;
				if ("self".equals(property)) {
					value = bctxt.getSelf();
				}
				if (Objects.equals(bctxt.getViewModelName(), property))
					value = bctxt.getViewModel();
			}

			// resolver first.
			if (value == null) {
				value = resolve(ctx, base, property);
			}
			if (value == null)
				value = getImplicitResolver().getValue(ctx, base, property);

			// it may be BeanName resolver
			if (value == null) {
				value = super.getELResolver().getValue(ctx, base, property);
			}
			if (value != null)
				ctx.setPropertyResolved(true);
		} else {
			value = super.getValue(ctx, base, property);
		}

		// in order to support more complex case, ex: .stream().filter(x -> x.contains(vm.value))
		final BindELContext bctx;
		ELContext ec = ((EvaluationContext) ctx).getELContext();
		if (ec instanceof BindELContext)
			bctx = (BindELContext) ec;
		else {
			bctx = (BindELContext) ((EvaluationContext) ec).getELContext();
		}

		Object ignoreRefVal = bctx.getAttribute(BinderImpl.IGNORE_REF_VALUE);

		//ZK-950: The expression reference doesn't update while change the instant of the reference
		final ReferenceBinding rbinding = value instanceof ReferenceBinding ? (ReferenceBinding) value : null;
		if (rbinding != null) {
			//ZK-3320 cause stack overflow
			if (property.equals(rbinding.getPropertyString())) {
				throw new RuntimeException("Property \"" + property + "\" is not allowed to be same as the reference expression in reference binding");
			}
			//ZK-1299 Use @ref and save after will cause null point exception
			if (Boolean.TRUE.equals(ignoreRefVal)) {
				return rbinding;
			}
			//			value = rbinding.getValue((BindELContext) ((EvaluationContext)ctx).getELContext());
			value = rbinding.getValue(bctx);
			final Object invalidateRef = bctx.getAttribute(BinderCtrl.INVALIDATE_REF_VALUE);
			if ("true".equalsIgnoreCase(String.valueOf(invalidateRef)))
				rbinding.invalidateCache();
		}
		//If value evaluated to a ReferenceBinding, always tie the ReferenceBinding itself as the 
		//evaluated bean, @see TrackerImpl#getLoadBindings0() and TrackerImpl#getAllTrackerNodesByBeanNodes()
		tieValue(ctx, base, property, rbinding != null ? rbinding : value, false);
		return value;
	}

	@Override
	public Object invoke(ELContext ctx, Object base, Object method, Class[] paramTypes, Object[] params)
			throws MethodNotFoundException {
		Object value = super.invoke(ctx, base, method, paramTypes, params);
		// in order to support more complex case, ex: .stream().filter(x -> x.contains(vm.value))
		final BindELContext bctx;
		ELContext ec = ((EvaluationContext) ctx).getELContext();
		if (ec instanceof BindELContext)
			bctx = (BindELContext) ec;
		else {
			bctx = (BindELContext) ((EvaluationContext) ec).getELContext();
		}

		Object ignoreRefVal = bctx.getAttribute(BinderImpl.IGNORE_REF_VALUE);

		//ZK-950: The expression reference doesn't update while change the instant of the reference
		final ReferenceBinding rbinding = value instanceof ReferenceBinding ? (ReferenceBinding) value : null;
		if (rbinding != null) {
			//ZK-1299 Use @ref and save after will cause null point exception
			if (Boolean.TRUE.equals(ignoreRefVal)) {
				return rbinding;
			}
			//			value = rbinding.getValue((BindELContext) ((EvaluationContext)ctx).getELContext());
			value = rbinding.getValue(bctx);
			final Object invalidateRef = bctx.getAttribute(BinderCtrl.INVALIDATE_REF_VALUE);
			if ("true".equalsIgnoreCase(String.valueOf(invalidateRef)))
				rbinding.invalidateCache();
		}

		AstMethodParameters mps = (AstMethodParameters) bctx.getContext(AstMethodParameters.class);

		if (mps != null) {
			String result = BindELContext.toNodeString(mps, new StringBuilder());

			Path newPath = new Path();
			newPath.add(String.valueOf(method) + result, String.valueOf(method) + result);
			bctx.putContext(Path.class, newPath);
		}
		//If value evaluated to a ReferenceBinding, always tie the ReferenceBinding itself as the 
		//evaluated bean, @see TrackerImpl#getLoadBindings0() and TrackerImpl#getAllTrackerNodesByBeanNodes()
		tieValue(ctx, base, method, rbinding != null ? rbinding : value, false);
		return value;
	}

	public void setValue(ELContext ctx, Object base, Object property, Object value)
			throws PropertyNotFoundException, PropertyNotWritableException, ELException {

		if (base == null) {
			//ZK-1085 PropertyNotWritableException when using reference binding
			//for setting value to a reference-binding and simple-node (base = null), we let reference-binding handle it 
			Object val = super.getValue(ctx, base, property); //property resolved sets true when getValue
			if (val instanceof ReferenceBinding) {
				((ReferenceBinding) val).setValue((BindELContext) ((EvaluationContext) ctx).getELContext(), value);
				return;
			}

		} else if (base instanceof ReferenceBinding) {
			base = ((ReferenceBinding) base).getValue((BindELContext) ((EvaluationContext) ctx).getELContext());
		}
		super.setValue(ctx, base, property, value);
		tieValue(ctx, base, property, value, true);
	}

	private static Path getPathList(BindELContext ctx) {
		return (Path) ctx.getContext(Path.class); //get path, see #PathResolver
	}

	//save value into equal beans
	private void saveEqualBeans(ELContext elCtx, Object base, String prop, Object value) {
		final BindELContext ctx = (BindELContext) ((EvaluationContext) elCtx).getELContext();

		final BindContext bctx = (BindContext) ctx.getAttribute(BinderImpl.BINDCTX);

		if (bctx.getAttribute(BinderImpl.SAVE_BASE) != null) { //recursive back, return
			return;
		}
		ctx.setAttribute(BinderImpl.SAVE_BASE, Boolean.TRUE);
		try {
			final Binder binder = bctx.getBinder();
			final TrackerImpl tracker = (TrackerImpl) ((BinderCtrl) binder).getTracker();
			final Set<Object> beans = tracker.getEqualBeans(base);
			Object originalBean = base;
			if (base instanceof FormProxyObject) {
				originalBean = ((FormProxyObject) base).getOriginObject();
			}
			beans.remove(base);
			for (Object candidate : beans) {
				if (candidate instanceof FormProxyObject) {
					Object originalCandidate = ((FormProxyObject) candidate).getOriginObject();
					if (Objects.equals(originalBean, originalCandidate))
						continue;
				}
				super.setValue(elCtx, candidate, prop, value); //might recursive back
			}
		} finally {
			ctx.setAttribute(BinderImpl.SAVE_BASE, null);
		}
	}

	//update dependency and notify changed
	protected void tieValue(ELContext elCtx, Object base, Object property, Object value, boolean allownotify) {
		//in order to support more complex case, ex: .stream().filter(x -> x.contains(vm.value))
		final BindELContext ctx;
		ELContext ec = ((EvaluationContext) elCtx).getELContext();
		if (ec instanceof BindELContext)
			ctx = (BindELContext) ec;
		else {
			ctx = (BindELContext) ((EvaluationContext) ec).getELContext();
		}

		if (ctx.ignoreTracker())
			return;
		final Binding binding = ctx.getBinding();
		//only there is a binding that needs tie tracking to value
		if (binding != null) {
			// In F80-ZK-2696.zul test case, the getContext() with Integer.class may be null
			// so we put -1 to skip the following condition with nums.
			final int nums = ctx.getContext(Integer.class) == null ? -1
					: ((Integer) ctx.getContext(Integer.class)).intValue(); //get numOfKids, see #PathResolver
			final Path path = getPathList(ctx);

			String script = null;
			//ZK-1960 save binding to an array throws ClassCastException
			String propName = property == null ? null : property.toString();
			boolean isForm = base instanceof Form;
			//ZK-1189, form shouldn't count on property directly
			String formFieldName = null;
			if (isForm) {
				script = path != null ? path.getTrackFieldName() : null; //script is the expression, ex, bean[a.b.c]
				formFieldName = path != null ? path.getAccessFieldName() : null; //filedname is the evaluated value, ex, bean.k (a.b.c is k in script case)
			} else {
				script = path != null ? path.getTrackProperty() : null;
			}
			final Binder binder = binding.getBinder();
			final BindContext bctx = (BindContext) ctx.getAttribute(BinderImpl.BINDCTX);
			final Component ctxcomp = bctx != null ? bctx.getComponent() : binding.getComponent();
			((BinderCtrl) binder).getTracker().tieValue(ctxcomp, base, script, propName, value,
					path != null ? path.getTrackBasePath() : null);

			if (base != null) {
				if (binding instanceof SaveBinding) {
					if (nums == 0) { //a done save operation, form or not form
						//handle equal beans
						saveEqualBeans(elCtx, base, (String) propName, value);

						//ZK-913 Value is reload after validation fail, 
						//only when notify is allowed.
						//parse @NotifyChange and collect Property to publish PropertyChangeEvent
						if (allownotify) {
							//ZK-905 Save into a Form should fire NotifyChange
							if (isForm) {
								//collect notify property, kept in BindContext

								//notify indirect form properties that have same expression, 
								//ex: bean[a.b.c] of fx, whose expression is 'bean[a.b.c]'
								BindELContext.addNotifys(base, script, value, bctx);
								//notify form property whose value equals expression result, 
								//ex, bean[a.b.c] of fx, if a.b.c is 'prop', them it notify bean.prop of fx 
								if (!script.equals(formFieldName)) {
									BindELContext.addNotifys(base, (String) formFieldName, value, bctx);
								}
								if (base instanceof Form)
									BindELContext.addNotifys(((Form) base).getFormStatus(), ".", null, bctx);
							} else {
								final Method m = (Method) ctx.getContext(Method.class);
								//collect Property for @NotifyChange, kept in BindContext
								//see BinderImpl$CommandEventListener#onEvent()
								BindELContext.addNotifys(m, base, (String) propName, value, bctx);
							}
						}
					}
				} else if (!(base instanceof Form) && binding instanceof LoadBinding) { //no @DependsOn in Form bean
					//parse @DependsOn and add into dependency tracking
					final Method m = (Method) ctx.getContext(Method.class);
					final Object mBase = ctx.getContext(MethodInfo.class);
					if (m != null && mBase == base) {
						final boolean prompt = bctx != null && bctx.getCommandName() == null;
						if (prompt) {
							//FormBinding shall not check @DependsOn() for dependent nodes
							String basePath = path != null ? path.getTrackBasePath() : null;
							boolean skipAddingDependsOn = (basePath == null || basePath.length() == 0); //Should ignore empty base
							if (!skipAddingDependsOn && (!(binding instanceof LoadFormBindingImpl)
									|| ((LoadFormBindingImpl) binding).getSeriesLength() <= path.size())) {
								BindELContext.addDependsOnTrackings(m, basePath, path != null ? path.getTrackFieldsList() : null, 
								binding, bctx);
							}
						}
					}
				}

				if (binding instanceof ReferenceBinding && nums == 0 && allownotify) {
					final Method m = (Method) ctx.getContext(Method.class);
					//collect Property for @NotifyChange, kept in BindContext
					//see BinderImpl$CommandEventListener#onEvent()
					BindELContext.addNotifys(m, base, (String) propName, value, bctx);
				}
			}
		}
	}
}
