package org.apache.log4j.config;

import org.apache.log4j.Appender;
import org.apache.log4j.Level;
import org.apache.log4j.Priority;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.helpers.OptionConverter;
import org.apache.log4j.spi.OptionHandler;
import org.apache.log4j.spi.ErrorHandler;

import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.io.InterruptedIOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Enumeration;
import java.util.Properties;

/**
 * General purpose Object property setter. Clients repeatedly invokes
 * {@link #setProperty setProperty(name,value)} in order to invoke setters
 * on the Object specified in the constructor. This class relies on the
 * JavaBeans {@link Introspector} to analyze the given Object Class using
 * reflection.
 * 
 * <p>
 * Usage:
 * 
 * <pre>
 * PropertySetter ps = new PropertySetter(anObject);
 * ps.set("name", "Joe");
 * ps.set("age", "32");
 * ps.set("isMale", "true");
 * </pre>
 * 
 * will cause the invocations anObject.setName("Joe"), anObject.setAge(32),
 * and setMale(true) if such methods exist with those signatures.
 * Otherwise an {@link IntrospectionException} are thrown.
 * 
 * @author Anders Kristensen
 * @since 1.1
 */
public class PropertySetter
{
	protected Object obj;
	protected PropertyDescriptor[] props;

	/**
	 * Create a new PropertySetter for the specified Object. This is done
	 * in prepartion for invoking {@link #setProperty} one or more times.
	 * 
	 * @param obj
	 *            the object for which to set properties
	 */
	public PropertySetter(Object obj)
	{
		this.obj = obj;
	}

	/**
	 * Uses JavaBeans {@link Introspector} to computer setters of object to be
	 * configured.
	 */
	protected void introspect()
	{
		try
		{
			BeanInfo bi = Introspector.getBeanInfo(obj.getClass());
			props = bi.getPropertyDescriptors();
		}
		catch (IntrospectionException ex)
		{
			LogLog.error("Failed to introspect " + obj + ": " + ex.getMessage());
			props = new PropertyDescriptor[0];
		}
	}

	/**
	 * Set the properties of an object passed as a parameter in one
	 * go. The <code>properties</code> are parsed relative to a
	 * <code>prefix</code>.
	 * 
	 * @param obj
	 *            The object to configure.
	 * @param properties
	 *            A java.util.Properties containing keys and values.
	 * @param prefix
	 *            Only keys having the specified prefix will be set.
	 */
	public static void setProperties(Object obj, Properties properties, String prefix)
	{
		new PropertySetter(obj).setProperties(properties, prefix);
	}

	/**
	 * Set the properites for the object that match the
	 * <code>prefix</code> passed as parameter.
	 * 
	 * 
	 */
	public void setProperties(Properties properties, String prefix)
	{
		int len = prefix.length();

		for (Enumeration e = properties.propertyNames(); e.hasMoreElements();)
		{
			String key = (String) e.nextElement();

			// handle only properties that start with the desired frefix.
			if (key.startsWith(prefix))
			{

				// ignore key if it contains dots after the prefix
				if (key.indexOf('.', len + 1) > 0)
				{
					// System.err.println("----------Ignoring---["+key
					// +"], prefix=["+prefix+"].");
					continue;
				}

				String value = OptionConverter.findAndSubst(key, properties);
				key = key.substring(len);
				if (("layout".equals(key) || "errorhandler".equals(key)) && obj instanceof Appender)
				{
					continue;
				}
				//
				// if the property type is an OptionHandler
				// (for example, triggeringPolicy of org.apache.log4j.rolling.RollingFileAppender)
				PropertyDescriptor prop = getPropertyDescriptor(Introspector.decapitalize(key));
				if (prop != null && OptionHandler.class.isAssignableFrom(prop.getPropertyType()) && prop.getWriteMethod() != null)
				{
					OptionHandler opt = (OptionHandler) OptionConverter.instantiateByKey(properties, prefix + key, prop.getPropertyType(), null);
					PropertySetter setter = new PropertySetter(opt);
					setter.setProperties(properties, prefix + key + ".");
					try
					{
						Method writeMethod = prop.getWriteMethod();
						System.out.println("woqu=" + writeMethod);
						prop.getWriteMethod().invoke(this.obj, new Object[] { opt });
					}
					catch (IllegalAccessException ex)
					{
						LogLog.warn("Failed to set property [" + key + "] to value \"" + value + "\". ", ex);
					}
					catch (InvocationTargetException ex)
					{
						if (ex.getTargetException() instanceof InterruptedException || ex.getTargetException() instanceof InterruptedIOException)
						{
							Thread.currentThread().interrupt();
						}
						LogLog.warn("Failed to set property [" + key + "] to value \"" + value + "\". ", ex);
					}
					catch (RuntimeException ex)
					{
						LogLog.warn("Failed to set property [" + key + "] to value \"" + value + "\". ", ex);
					}
					continue;
				}

				setProperty(key, value);
			}
		}
		activate();
	}

	/**
	 * Set a property on this PropertySetter's Object. If successful, this
	 * method will invoke a setter method on the underlying Object. The
	 * setter is the one for the specified property name and the value is
	 * determined partly from the setter argument type and partly from the
	 * value specified in the call to this method.
	 * 
	 * <p>
	 * If the setter expects a String no conversion is necessary.
	 * If it expects an int, then an attempt is made to convert 'value'
	 * to an int using new Integer(value). If the setter expects a boolean,
	 * the conversion is by new Boolean(value).
	 * 
	 * @param name
	 *            name of the property
	 * @param value
	 *            String value of the property
	 */
	public void setProperty(String name, String value)
	{
		if (value == null)
		{
			return;
		}

		name = Introspector.decapitalize(name);
		PropertyDescriptor prop = getPropertyDescriptor(name);

		// LogLog.debug("---------Key: "+name+", type="+prop.getPropertyType());

		if (prop == null)
		{
			LogLog.warn("No such property [" + name + "] in " + obj.getClass().getName() + ".");
		}
		else
		{
			try
			{
				setProperty(prop, name, value);
			}
			catch (PropertySetterException ex)
			{
				LogLog.warn("Failed to set property [" + name + "] to value \"" + value + "\". ", ex.rootCause);
			}
		}
	}

	/**
	 * Set the named property given a {@link PropertyDescriptor}.
	 * 
	 * @param prop
	 *            A PropertyDescriptor describing the characteristics
	 *            of the property to set.
	 * @param name
	 *            The named of the property to set.
	 * @param value
	 *            The value of the property.
	 */
	public void setProperty(PropertyDescriptor prop, String name, String value) throws PropertySetterException
	{
		Method setter = prop.getWriteMethod();
		if (setter == null)
		{
			throw new PropertySetterException("No setter for property [" + name + "].");
		}
		Class[] paramTypes = setter.getParameterTypes();
		if (paramTypes.length != 1)
		{
			throw new PropertySetterException("#params for setter != 1");
		}

		Object arg;
		try
		{
			arg = convertArg(value, paramTypes[0]);
		}
		catch (Throwable t)
		{
			throw new PropertySetterException("Conversion to type [" + paramTypes[0] + "] failed. Reason: " + t);
		}
		if (arg == null)
		{
			throw new PropertySetterException("Conversion to type [" + paramTypes[0] + "] failed.");
		}
		LogLog.debug("Setting property [" + name + "] to [" + arg + "].");
		try
		{
			setter.invoke(obj, new Object[] { arg });
		}
		catch (IllegalAccessException ex)
		{
			throw new PropertySetterException(ex);
		}
		catch (InvocationTargetException ex)
		{
			if (ex.getTargetException() instanceof InterruptedException || ex.getTargetException() instanceof InterruptedIOException)
			{
				Thread.currentThread().interrupt();
			}
			throw new PropertySetterException(ex);
		}
		catch (RuntimeException ex)
		{
			throw new PropertySetterException(ex);
		}
	}

	/**
	 * Convert <code>val</code> a String parameter to an object of a
	 * given type.
	 */
	protected Object convertArg(String val, Class type)
	{
		if (val == null)
		{
			return null;
		}

		String v = val.trim();
		if (String.class.isAssignableFrom(type))
		{
			return val;
		}
		else if (Integer.TYPE.isAssignableFrom(type))
		{
			return new Integer(v);
		}
		else if (Long.TYPE.isAssignableFrom(type))
		{
			return new Long(v);
		}
		else if (Boolean.TYPE.isAssignableFrom(type))
		{
			if ("true".equalsIgnoreCase(v))
			{
				return Boolean.TRUE;
			}
			else if ("false".equalsIgnoreCase(v))
			{
				return Boolean.FALSE;
			}
		}
		else if (Priority.class.isAssignableFrom(type))
		{
			return OptionConverter.toLevel(v, Level.DEBUG);
		}
		else if (ErrorHandler.class.isAssignableFrom(type))
		{
			return OptionConverter.instantiateByClassName(v, ErrorHandler.class, null);
		}
		return null;
	}

	protected PropertyDescriptor getPropertyDescriptor(String name)
	{
		if (props == null)
		{
			introspect();
		}

		for (int i = 0; i < props.length; i++)
		{
			if (name.equals(props[i].getName()))
			{
				return props[i];
			}
		}
		return null;
	}

	public void activate()
	{
		if (obj instanceof OptionHandler)
		{
			((OptionHandler) obj).activateOptions();
		}
	}
}