/* sbt -- Simple Build Tool
 * Copyright 2008 David MacIver, Mark Harrah
 */
package sbt

import scala.collection._

object ReflectUtilities
{
	/** Converts the camelCase String `name` to lowercase separated by `separator`. */
	def transformCamelCase(name: String, separator: Char): String =
	{
		val buffer = new StringBuilder
		for(char <- name)
		{
			import java.lang.Character._
			if(isUpperCase(char))
			{
				buffer += separator
				buffer += toLowerCase(char)
			}
			else
				buffer += char
		}
		buffer.toString
	}

	def ancestry(clazz : Class[_]) : List[Class[_]] = 
		if (clazz == classOf[AnyRef] || !classOf[AnyRef].isAssignableFrom(clazz)) List(clazz)
		else clazz :: ancestry(clazz.getSuperclass);

	def fields(clazz : Class[_]) = 
		mutable.OpenHashMap(ancestry(clazz).
			flatMap(_.getDeclaredFields).
			map(f => (f.getName, f)):_*)
	
	/** Collects all `val`s of type `T` defined on value `self`.
	* The returned Map maps the name of each `val` to its value.
	* This depends on scalac implementation details to determine what is a `val` using only Java reflection. */
	def allValsC[T](self: AnyRef, clazz: Class[T]): immutable.SortedMap[String, T] =
	{
		var mappings = new immutable.TreeMap[String, T]
		val correspondingFields = fields(self.getClass)
		for(method <- self.getClass.getMethods)
		{
			if(method.getParameterTypes.length == 0 && clazz.isAssignableFrom(method.getReturnType))
			{
				for(field <- correspondingFields.get(method.getName) if field.getType == method.getReturnType)
				{
					val value = method.invoke(self).asInstanceOf[T]
					if(value == null) throw new UninitializedVal(method.getName, method.getDeclaringClass.getName)
					mappings += ((method.getName, value))
				}
			}
		}
		mappings
	}

	/** Collects all `val`s of type `T` defined on value `self`.
	* The returned Map maps the name of each `val` to its value.
	* This requires an available `Manifest` for `T` and depends on scalac implementation details to determine
	* what is a `val` using only Java reflection. */
	def allVals[T](self: AnyRef)(implicit mt: scala.reflect.Manifest[T]): immutable.SortedMap[String, T] =
		allValsC(self, mt.runtimeClass).asInstanceOf[immutable.SortedMap[String,T]]
}

/** An exception to indicate that while traversing the `val`s for an instance of `className`, the `val` named `valName` was `null`. */
final class UninitializedVal(val valName: String, val className: String) extends RuntimeException("val " + valName + " in class " + className + " was null.\nThis is probably an initialization problem and a 'lazy val' should be used.")