/*
  GRANITE DATA SERVICES
  Copyright (C) 2011 GRANITE DATA SERVICES S.A.S.

  This file is part of Granite Data Services.

  Granite Data Services is free software; you can redistribute it and/or modify
  it under the terms of the GNU Library General Public License as published by
  the Free Software Foundation; either version 2 of the License, or (at your
  option) any later version.

  Granite Data Services is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License
  for more details.

  You should have received a copy of the GNU Library General Public License
  along with this library; if not, see <http://www.gnu.org/licenses/>.
*/

package org.granite.util;

import java.lang.annotation.Annotation;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.GenericArrayType;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.lang.reflect.WildcardType;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * @author Franck WOLFF
 */
public abstract class TypeUtil {

    public static Object newInstance(String type)
        throws ClassNotFoundException, InstantiationException, IllegalAccessException {
        return forName(type).newInstance();
    }

    public static <T> T newInstance(String type, Class<T> cast)
        throws ClassNotFoundException, InstantiationException, IllegalAccessException {
        return forName(type, cast).newInstance();
    }

    public static Object newInstance(String type, Class<?>[] argsClass, Object[] argsValues)
        throws ClassNotFoundException, InstantiationException, IllegalAccessException {
        return newInstance(forName(type), argsClass, argsValues);
    }

    @SuppressWarnings("unchecked")
    public static <T> T newInstance(Class<?> type, Class<T> cast)
        throws InstantiationException, IllegalAccessException {
        return (T)type.newInstance();
    }

    public static <T> T newInstance(Class<T> type, Class<?>[] argsClass, Object[] argsValues)
        throws InstantiationException, IllegalAccessException {
        T instance = null;
        try {
            Constructor<T> constructorDef = type.getConstructor(argsClass);
            instance = constructorDef.newInstance(argsValues);
        } catch (SecurityException e) {
            throw new InstantiationException(e.getMessage());
        } catch (NoSuchMethodException e) {
            throw new InstantiationException(e.getMessage());
        } catch (IllegalArgumentException e) {
            throw new InstantiationException(e.getMessage());
        } catch (InvocationTargetException e) {
            throw new InstantiationException(e.getMessage());
        }
        return instance;
    }

    public static Class<?> forName(String type) throws ClassNotFoundException {
        try {
                return TypeUtil.class.getClassLoader().loadClass(type);
        }
        catch (ClassNotFoundException e) {
                return Thread.currentThread().getContextClassLoader().loadClass(type);
        }
    }

    @SuppressWarnings("unchecked")
    public static <T> Class<T> forName(String type, Class<T> cast) throws ClassNotFoundException {
        try {
                return (Class<T>)TypeUtil.class.getClassLoader().loadClass(type);
        }
        catch (ClassNotFoundException e) {
                return (Class<T>)Thread.currentThread().getContextClassLoader().loadClass(type);
        }
    }

    public static Constructor<?> getConstructor(String type, Class<?>[] paramTypes)
        throws ClassNotFoundException, NoSuchMethodException {
        return getConstructor(forName(type), paramTypes);
    }

    public static <T> Constructor<T> getConstructor(Class<T> type, Class<?>[] paramTypes)
        throws NoSuchMethodException {
        return type.getConstructor(paramTypes);
    }

    public static <T> List<T> emptyList(Class<T> type) {
        return Collections.emptyList();
    }

    public static <T> Set<T> emptySet(Class<T> type) {
        return Collections.emptySet();
    }

    public static <T, U> Map<T, U> emptyMap(Class<T> keyType, Class<U> valueType) {
        return Collections.emptyMap();
    }

    public static boolean isPrimitive(Type type) {
        return type instanceof Class<?> && ((Class<?>)type).isPrimitive();
    }

    public static Class<?> classOfType(Type type) {
        if (type instanceof Class<?>)
            return (Class<?>)type;
        if (type instanceof ParameterizedType)
            return (Class<?>)((ParameterizedType)type).getRawType();
        if (type instanceof WildcardType) {
            // Forget lower bounds and only deal with first upper bound...
            Type[] ubs = ((WildcardType)type).getUpperBounds();
            if (ubs.length > 0)
                return classOfType(ubs[0]);
        }
        if (type instanceof GenericArrayType) {
            Class<?> ct = classOfType(((GenericArrayType)type).getGenericComponentType());
            return (ct != null ? Array.newInstance(ct, 0).getClass() : Object[].class);
        }
        if (type instanceof TypeVariable<?>) {
            // Only deal with first (upper) bound...
            Type[] ubs = ((TypeVariable<?>)type).getBounds();
            if (ubs.length > 0)
                return classOfType(ubs[0]);
        }
        // Should never append...
        return Object.class;
    }
    
    public static Type getBoundType(TypeVariable<?> typeVariable) {
        Type[] ubs = typeVariable.getBounds();
        if (ubs.length > 0)
                return ubs[0];
        
        // should never happen...
        if (typeVariable.getGenericDeclaration() instanceof Type)
                return (Type)typeVariable.getGenericDeclaration();
        return typeVariable;
    }
    
    public static ParameterizedType[] getDeclaringTypes(Class<?> type) {
                List<ParameterizedType> supertypes = new ArrayList<ParameterizedType>();
                
                Type stype = type.getGenericSuperclass();
                Class<?> sclass = type.getSuperclass();
                while (sclass != null && sclass != Object.class) {
                        if (stype instanceof ParameterizedType)
                                supertypes.add((ParameterizedType)stype);
                        stype = sclass.getGenericSuperclass();
                        sclass = sclass.getSuperclass();
                }
                
                collectGenericInterfaces(type.getGenericInterfaces(), supertypes);
                
                return supertypes.isEmpty() ? null : supertypes.toArray(new ParameterizedType[supertypes.size()]);
    }
    
    private static void collectGenericInterfaces(Type[] types, List<ParameterizedType> supertypes) {
        if (types == null)
                return;
                for (Type t : types) {
                        if (t instanceof ParameterizedType)
                                supertypes.add((ParameterizedType)t);
                        else
                                collectGenericInterfaces(((Class<?>)t).getGenericInterfaces(), supertypes);
                }
    }
   
    public static Type resolveTypeVariable(Type genericType, Class<?> declaringClass, ParameterizedType[] declaringTypes) {
        if (genericType instanceof TypeVariable && declaringTypes != null) {
                int index = -1;
                TypeVariable<?> typeVariable = (TypeVariable<?>)genericType;
                ParameterizedType declaringType = null;
                for (int j = 0; j < declaringClass.getTypeParameters().length; j++) {
                        Type typeParameter = declaringClass.getTypeParameters()[j];
                        if (typeParameter == typeVariable)
                                index = j;
                        else if (typeVariable.getBounds() != null) {
                                for (Type t : typeVariable.getBounds()) {
                                        if (typeParameter == t) {
                                                index = j;
                                                break;
                                        }
                                }
                        }
                        if (index >= 0) {
                                        for (ParameterizedType t : declaringTypes) {
                                                if (declaringClass.isAssignableFrom(classOfType(t))) {
                                                        declaringType = t;
                                                        break;
                                                }
                                        }
                                        break;
                        }
                }
                if (declaringType != null && index >= 0 && index < declaringType.getActualTypeArguments().length)
                        return declaringType.getActualTypeArguments()[index];
        }
        return genericType;
    }
    public static String getPackageName(Class<?> clazz) {
        return clazz.getPackage() != null ? clazz.getPackage().getName() : "";
    }
    
    public static PropertyDescriptor[] getProperties(Class<?> clazz) {
        try {
                PropertyDescriptor[] properties = Introspector.getPropertyDescriptors(clazz);
                Field[] fields = clazz.getDeclaredFields();
                for (Field field : fields) {
                        if (Boolean.class.equals(field.getType())) {
                                boolean found = false;
                                for (PropertyDescriptor property : properties) {
                                        if (property.getName().equals(field.getName())) {
                                                found = true;
                                                if (property.getReadMethod() == null) {
                                                        try {
                                                                Method readMethod = clazz.getDeclaredMethod(getIsMethodName(field.getName()));
                                                                if (Modifier.isPublic(readMethod.getModifiers()) && !Modifier.isStatic(readMethod.getModifiers()))
                                                                        property.setReadMethod(readMethod);
                                                        }
                                                        catch (NoSuchMethodException e) {
                                                        }
                                                }
                                                break;
                                        }
                                }
                                if (!found) {
                                                try {
                                                        Method readMethod = clazz.getDeclaredMethod(getIsMethodName(field.getName()));
                                                        if (Modifier.isPublic(readMethod.getModifiers()) && !Modifier.isStatic(readMethod.getModifiers())) {
                                                                PropertyDescriptor[] propertiesTmp = new PropertyDescriptor[properties.length + 1];
                                                                System.arraycopy(properties, 0, propertiesTmp, 0, properties.length);
                                                                propertiesTmp[properties.length] = new PropertyDescriptor(field.getName(), readMethod, null);
                                                                properties = propertiesTmp;
                                                        }
                                                }
                                                catch (NoSuchMethodException e) {
                                                }
                                }
                        }
                }
            return properties;
        } catch (Exception e) {
            throw new RuntimeException("Could not introspect properties of class: " + clazz, e);
        }
    }
    
    private static String getIsMethodName(String name) {
        return "is" + name.substring(0, 1).toUpperCase() + name.substring(1);
    }
   
    public static ClassLoader getClassLoader(Class<?> clazz) {
        return (clazz.getClassLoader() != null ? clazz.getClassLoader() : ClassLoader.getSystemClassLoader());
    }

    public static URL findResource(Class<?> clazz) {
        while (clazz.isArray())
            clazz = clazz.getComponentType();
        if (clazz.isPrimitive())
            return null;
        URL url = getClassLoader(clazz).getResource(toResourceName(clazz));
        String path = url.toString();
        if (path.indexOf(' ') != -1) {
                try {
                                url = new URL(path.replace(" ", "%20"));
                        } catch (MalformedURLException e) {
                                // should never happen...
                        }
        }
        return url;
    }

    public static String toResourceName(Class<?> clazz) {
        return clazz.getName().replace('.', '/').concat(".class");
    }
    
    public static String getMethodSignature(Method method) {
        StringBuilder sb = new StringBuilder();
        sb.append(method.getName()).append('(');
        Class<?>[] params = method.getParameterTypes();
        for (int i = 0; i < params.length; i++) {
                if (i > 0)
                        sb.append(',');
                sb.append(getTypeSignature(params[i]));
        }
        sb.append(')');
        return sb.toString();
    }
        
    public static String getTypeSignature(Class<?> type) {
                if (type.isArray()) {
                    try {
                                int dimensions = 1;
                                Class<?> clazz = type.getComponentType();
                                while (clazz.isArray()) {
                                        dimensions++;
                                        clazz = clazz.getComponentType();
                                }
                                
                                StringBuffer sb = new StringBuffer(clazz.getName());
                                while (dimensions-- > 0)
                                    sb.append("[]");
                                return sb.toString();
                    } catch (Throwable e) {
                        // fallback...
                    }
                }
                return type.getName();
        }
    
    public static Method getMethod(Class<?> clazz, String signature) throws NoSuchMethodException {
        signature = StringUtil.removeSpaces(signature);
                
        if (!signature.endsWith(")"))
                        signature += "()";
                
                for (Method method : clazz.getMethods()) {
                        if (signature.equals(getMethodSignature(method)))
                                return method;
                }
                
                throw new NoSuchMethodException("Could not find method: " + signature + " in class: " + clazz);
    }
    
    public static boolean isAnnotationPresent(AnnotatedElement elmt, Class<? extends Annotation> annotationClass) {
        return getAnnotation(elmt, annotationClass) != null;
    }
    
    public static <T extends Annotation> DeclaredAnnotation<T> getAnnotation(AnnotatedElement elmt, Class<T> annotationClass) {
        T annotation = elmt.getAnnotation(annotationClass);
        
        if (annotation != null) {
                Class<?> declaringClass = (elmt instanceof Member ? ((Member)elmt).getDeclaringClass() : (Class<?>)elmt);
                return new DeclaredAnnotation<T>(annotation, elmt, declaringClass);
        }
        
        if (elmt instanceof Field)
                return null;
        
        if (elmt instanceof Method) {
                Method m = (Method)elmt;
                return getMethodAnnotation(m.getDeclaringClass(), m.getName(), m.getParameterTypes(), annotationClass);
        }
        
        if (elmt instanceof Constructor) {
                Constructor<?> c = (Constructor<?>)elmt;
                return getConstructorAnnotation(c.getDeclaringClass(), annotationClass);
        }
        
        if (elmt instanceof Class) {
                Class<?> c = (Class<?>)elmt;
                return getClassAnnotation(c.getDeclaringClass(), annotationClass);
        }
        
        throw new RuntimeException("Unsupported annotated element: " + elmt);
    }
    
    public static <T extends Annotation> DeclaredAnnotation<T> getMethodAnnotation(Class<?> clazz, String name, Class<?>[] parameterTypes, Class<T> annotationClass) {
        DeclaredAnnotation<T> declaredAnnotation = null;
        
        try {
                Method method = clazz.getDeclaredMethod(name, parameterTypes);
                T annotation = clazz.getDeclaredMethod(name, parameterTypes).getAnnotation(annotationClass);
                if (annotation != null)
                        declaredAnnotation = new DeclaredAnnotation<T>(annotation, method, clazz);
        }
        catch (NoSuchMethodException e) {
                // fallback...
        }
        
        if (declaredAnnotation == null && clazz.getSuperclass() != null)
                declaredAnnotation = getMethodAnnotation(clazz.getSuperclass(), name, parameterTypes, annotationClass);
        
        if (declaredAnnotation == null) {
                for (Class<?> interfaze : clazz.getInterfaces()) {
                        declaredAnnotation = getMethodAnnotation(interfaze, name, parameterTypes, annotationClass);
                        if (declaredAnnotation != null)
                                break;
                }
        }
                
        return declaredAnnotation;
    }
    
    public static <T extends Annotation> DeclaredAnnotation<T> getConstructorAnnotation(Class<?> clazz, Class<T> annotationClass) {
        DeclaredAnnotation<T> declaredAnnotation = null;
        
        for (Constructor<?> constructor : clazz.getDeclaredConstructors()) {
                T annotation = constructor.getAnnotation(annotationClass);
                if (annotation != null) {
                        declaredAnnotation = new DeclaredAnnotation<T>(annotation, constructor, clazz);
                        break;
                }
        }
        
        if (declaredAnnotation == null && clazz.getSuperclass() != null)
                declaredAnnotation = getConstructorAnnotation(clazz.getSuperclass(), annotationClass);
                
        return declaredAnnotation;
    }
    
    public static <T extends Annotation> DeclaredAnnotation<T> getClassAnnotation(Class<?> clazz, Class<T> annotationClass) {
        DeclaredAnnotation<T> declaredAnnotation = null;
        
        T annotation = clazz.getAnnotation(annotationClass);
        if (annotation != null)
                declaredAnnotation = new DeclaredAnnotation<T>(annotation, clazz, clazz);
        else {
                if (clazz.getSuperclass() != null)
                        declaredAnnotation = getClassAnnotation(clazz.getSuperclass(), annotationClass);
                
                if (declaredAnnotation == null) {
                        for (Class<?> interfaze : clazz.getInterfaces()) {
                                declaredAnnotation = getClassAnnotation(interfaze, annotationClass);
                                if (declaredAnnotation != null)
                                        break;
                        }
                }
        }
                
        return declaredAnnotation;
    }
    
    public static class DeclaredAnnotation<T extends Annotation> {

        public final T annotation;
        public final AnnotatedElement annotatedElement;
        public final Class<?> declaringClass;
                
        public DeclaredAnnotation(T annotation, AnnotatedElement annotatedElement, Class<?> declaringClass) {
                        this.annotation = annotation;
                        this.annotatedElement = annotatedElement;
                        this.declaringClass = declaringClass;
                }

                @Override
                public String toString() {
                        return getClass().getName() + "{annotation=" + annotation + ", annotatedElement=" + annotatedElement + ", declaringClass=" + declaringClass + "}";
                }
    }
}