/* sbt -- Simple Build Tool
 * Copyright 2009, 2010  Mark Harrah
 */
package sbt
package classfile

import scala.collection.mutable
import mutable.{ArrayBuffer, Buffer}
import scala.annotation.tailrec
import java.io.File
import java.lang.annotation.Annotation
import java.lang.reflect.Method
import java.lang.reflect.Modifier.{STATIC, PUBLIC, ABSTRACT}

private[sbt] object Analyze
{
	def apply[T](outputDirectory: File, sources: Seq[File], log: Logger)(analysis: xsbti.AnalysisCallback, loader: ClassLoader, readAPI: (File,Seq[Class[_]]) => Unit)(compile: => Unit)
	{
		val sourceMap = sources.toSet[File].groupBy(_.getName)
		val classesFinder = PathFinder(outputDirectory) ** "*.class"
		val existingClasses = classesFinder.get

		def load(tpe: String, errMsg: => Option[String]): Option[Class[_]] =
			try { Some(Class.forName(tpe, false, loader)) }
			catch { case e => errMsg.foreach(msg => log.warn(msg + " : " +e.toString)); None }

		// runs after compilation
		def analyze()
		{
			val allClasses = Set(classesFinder.get: _*)
			val newClasses = allClasses -- existingClasses
			
			val productToSource = new mutable.HashMap[File, File]
			val sourceToClassFiles = new mutable.HashMap[File, Buffer[ClassFile]]

			// parse class files and assign classes to sources.  This must be done before dependencies, since the information comes
			// as class->class dependencies that must be mapped back to source->class dependencies using the source+class assignment
			for(newClass <- newClasses;
				classFile = Parser(newClass);
				sourceFile <- classFile.sourceFile orElse guessSourceName(newClass.getName);
				source <- guessSourcePath(sourceMap, classFile, log))
			{
				analysis.beginSource(source)
				analysis.generatedClass(source, newClass, classFile.className)
				productToSource(newClass) = source
				sourceToClassFiles.getOrElseUpdate(source, new ArrayBuffer[ClassFile]) += classFile
			}
			
			// get class to class dependencies and map back to source to class dependencies
			for( (source, classFiles) <- sourceToClassFiles )
			{
				def processDependency(tpe: String)
				{
					trapAndLog(log)
					{
						val loaded = load(tpe, Some("Problem processing dependencies of source " + source))
						for(clazz <- loaded; file <- ErrorHandling.convert(IO.classLocationFile(clazz)).right)
						{
							val name = clazz.getName
							if(file.isDirectory)
							{
								val resolved = resolveClassFile(file, tpe)
								assume(resolved.exists, "Resolved class file " + resolved + " from " + source + " did not exist")
								if(file == outputDirectory)
								{
									productToSource.get(resolved) match
									{
										case Some(dependsOn) => analysis.sourceDependency(dependsOn, source)
										case None => analysis.binaryDependency(resolved, clazz.getName, source)
									}
								}
								else
									analysis.binaryDependency(resolved, name, source)
							}
							else
								analysis.binaryDependency(file, name, source)
						}
					}
				}
				
				classFiles.flatMap(_.types).foreach(processDependency)
				readAPI(source, classFiles.toSeq.flatMap(c => load(c.className, Some("Error reading API from class file") )))
				analysis.endSource(source)
			}

			for( source <- sources filterNot sourceToClassFiles.keySet ) {
				analysis.beginSource(source)
				analysis.api(source, new xsbti.api.SourceAPI(Array(), Array()))
				analysis.endSource(source)
			}
		}
		
		compile
		analyze()
	}
	private def trapAndLog(log: Logger)(execute: => Unit)
	{
		try { execute }
		catch { case e => log.trace(e); log.error(e.toString) }
	}
	private def guessSourceName(name: String) = Some( takeToDollar(trimClassExt(name)) )
	private def takeToDollar(name: String) =
	{
		val dollar = name.indexOf('$')
		if(dollar < 0) name else name.substring(0, dollar)
	}
	private final val ClassExt = ".class"
	private def trimClassExt(name: String) = if(name.endsWith(ClassExt)) name.substring(0, name.length - ClassExt.length) else name
	private def resolveClassFile(file: File, className: String): File = (file /: (className.replace('.','/') + ClassExt).split("/"))(new File(_, _))
	private def guessSourcePath(sourceNameMap: Map[String, Set[File]], classFile: ClassFile, log: Logger) =
	{
		val classNameParts = classFile.className.split("""\.""")
		val pkg = classNameParts.init
		val simpleClassName = classNameParts.last
		val sourceFileName = classFile.sourceFile.getOrElse(simpleClassName.takeWhile(_ != '$').mkString("", "", ".java"))
		val candidates = findSource(sourceNameMap, pkg.toList, sourceFileName)
		candidates match
		{
			case Nil => log.warn("Could not determine source for class " + classFile.className)
			case head :: Nil => ()
			case _ => log.warn("Multiple sources matched for class " + classFile.className + ": " + candidates.mkString(", "))
		}
		candidates
	}
	private def findSource(sourceNameMap: Map[String, Iterable[File]], pkg: List[String], sourceFileName: String): List[File] =
		refine( (sourceNameMap get sourceFileName).toList.flatten.map { x => (x,x.getParentFile) }, pkg.reverse)
	
	@tailrec private def refine(sources: List[(File, File)], pkgRev: List[String]): List[File] =
	{
		def make = sources.map(_._1)
		if(sources.isEmpty || sources.tail.isEmpty)
			make
		else
			pkgRev match
			{
				case Nil => shortest(make)
				case x :: xs =>
					val retain = sources flatMap { case (src, pre) =>
						if(pre != null && pre.getName == x)
							(src, pre.getParentFile) :: Nil
						else
							Nil
					}
					refine(retain, xs)
			}
	}
	private def shortest(files: List[File]): List[File] =
		if(files.isEmpty) files
		else
		{
			val fs = files.groupBy(distanceToRoot(0))
			fs(fs.keys.min)
		}

	private def distanceToRoot(acc: Int)(file: File): Int =
		if(file == null) acc else distanceToRoot(acc + 1)(file.getParentFile)

	private def isTopLevel(classFile: ClassFile) = classFile.className.indexOf('$') < 0
	private lazy val unit = classOf[Unit]
	private lazy val strArray = List(classOf[Array[String]])

	private def isMain(method: Method): Boolean =
		method.getName == "main" &&
		isMain(method.getModifiers) &&
		method.getReturnType == unit &&
		method.getParameterTypes.toList == strArray
	private def isMain(modifiers: Int): Boolean = (modifiers & mainModifiers) == mainModifiers && (modifiers & notMainModifiers) == 0
	
	private val mainModifiers = STATIC  | PUBLIC
	private val notMainModifiers = ABSTRACT
}