/*
 * Based on JUEL 2.2.1 code, 2006-2009 Odysseus Software GmbH
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.activiti.engine.impl.juel;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Arrays;

import org.activiti.engine.impl.javax.el.ELContext;
import org.activiti.engine.impl.javax.el.ELException;
import org.activiti.engine.impl.javax.el.MethodInfo;
import org.activiti.engine.impl.javax.el.MethodNotFoundException;
import org.activiti.engine.impl.javax.el.PropertyNotFoundException;
import org.activiti.engine.impl.javax.el.ValueExpression;
import org.activiti.engine.impl.javax.el.ValueReference;

public class AstIdentifier extends AstNode implements IdentifierNode {
    private final String name;
    private final int index;

    public AstIdentifier(String name, int index) {
        this.name = name;
        this.index = index;
    }

    public Class<?> getType(Bindings bindings, ELContext context) {
        ValueExpression expression = bindings.getVariable(index);
        if (expression != null) {
            return expression.getType(context);
        }
        context.setPropertyResolved(false);
        Class<?> result = context.getELResolver().getType(context, null, name);
        if (!context.isPropertyResolved()) {
            throw new PropertyNotFoundException(LocalMessages.get("error.identifier.property.notfound", name));
        }
        return result;
    }

    public boolean isLeftValue() {
        return true;
    }

    public boolean isMethodInvocation() {
        return false;
    }

    public boolean isLiteralText() {
        return false;
    }

    public ValueReference getValueReference(Bindings bindings, ELContext context) {
        ValueExpression expression = bindings.getVariable(index);
        if (expression != null) {
            return expression.getValueReference(context);
        }
        return new ValueReference(null, name);
    }

    @Override
    public Object eval(Bindings bindings, ELContext context) {
        ValueExpression expression = bindings.getVariable(index);
        if (expression != null) {
            return expression.getValue(context);
        }
        context.setPropertyResolved(false);
        Object result = context.getELResolver().getValue(context, null, name);
        if (!context.isPropertyResolved()) {
            throw new PropertyNotFoundException(LocalMessages.get("error.identifier.property.notfound", name));
        }
        return result;
    }

    public void setValue(Bindings bindings, ELContext context, Object value) {
        ValueExpression expression = bindings.getVariable(index);
        if (expression != null) {
            expression.setValue(context, value);
            return;
        }
        context.setPropertyResolved(false);
        context.getELResolver().setValue(context, null, name, value);
        if (!context.isPropertyResolved()) {
            throw new PropertyNotFoundException(LocalMessages.get("error.identifier.property.notfound", name));
        }
    }

    public boolean isReadOnly(Bindings bindings, ELContext context) {
        ValueExpression expression = bindings.getVariable(index);
        if (expression != null) {
            return expression.isReadOnly(context);
        }
        context.setPropertyResolved(false);
        boolean result = context.getELResolver().isReadOnly(context, null, name);
        if (!context.isPropertyResolved()) {
            throw new PropertyNotFoundException(LocalMessages.get("error.identifier.property.notfound", name));
        }
        return result;
    }

    protected Method getMethod(Bindings bindings, ELContext context, Class<?> returnType, Class<?>[] paramTypes) {
        Object value = eval(bindings, context);
        if (value == null) {
            throw new MethodNotFoundException(LocalMessages.get("error.identifier.method.notfound", name));
        }
        if (value instanceof Method) {
            Method method = (Method) value;
            if (returnType != null && !returnType.isAssignableFrom(method.getReturnType())) {
                throw new MethodNotFoundException(LocalMessages.get("error.identifier.method.notfound", name));
            }
            if (!Arrays.equals(method.getParameterTypes(), paramTypes)) {
                throw new MethodNotFoundException(LocalMessages.get("error.identifier.method.notfound", name));
            }
            return method;
        }
        throw new MethodNotFoundException(LocalMessages.get("error.identifier.method.notamethod", name, value.getClass()));
    }

    public MethodInfo getMethodInfo(Bindings bindings, ELContext context, Class<?> returnType, Class<?>[] paramTypes) {
        Method method = getMethod(bindings, context, returnType, paramTypes);
        return new MethodInfo(method.getName(), method.getReturnType(), paramTypes);
    }

    public Object invoke(Bindings bindings, ELContext context, Class<?> returnType, Class<?>[] paramTypes, Object[] params) {
        Method method = getMethod(bindings, context, returnType, paramTypes);
        try {
            return method.invoke(null, params);
        } catch (IllegalAccessException e) {
            throw new ELException(LocalMessages.get("error.identifier.method.access", name));
        } catch (IllegalArgumentException e) {
            throw new ELException(LocalMessages.get("error.identifier.method.invocation", name, e));
        } catch (InvocationTargetException e) {
            throw new ELException(LocalMessages.get("error.identifier.method.invocation", name, e.getCause()));
        }
    }

    @Override
    public String toString() {
        return name;
    }

    @Override
    public void appendStructure(StringBuilder b, Bindings bindings) {
        b.append(bindings != null && bindings.isVariableBound(index) ? "<var>" : name);
    }

    public int getIndex() {
        return index;
    }

    public String getName() {
        return name;
    }

    public int getCardinality() {
        return 0;
    }

    public AstNode getChild(int i) {
        return null;
    }
}
