package sbt

	import java.io.File
	import Scoped.Apply
	import Project.{AppConfig, Config, Setting, ThisProject, ThisProjectRef}
	import Configurations.{Compile => CompileConf, Test => TestConf}
	import Command.HistoryPath
	import EvaluateTask.streams
	import inc.Analysis
	import std.TaskExtra._
	import scala.xml.{Node => XNode,NodeSeq}
	import org.apache.ivy.core.module.{descriptor, id}
	import descriptor.ModuleDescriptor, id.ModuleRevisionId

object Keys
{
	val Base = SettingKey[File]("base-directory")
	val Target = SettingKey[File]("target")
	val Source = SettingKey[File]("source-directory")
	val SourceManaged = SettingKey[File]("source-managed-directory")
	val ScalaSource = SettingKey[File]("scala-source-directory")
	val JavaSource = SettingKey[File]("java-source-directory")
	val JavaSourceRoots = SettingKey[Seq[File]]("java-source-directories")
	val ResourceDir = SettingKey[File]("resource-directory")
	val SourceDirectories = SettingKey[Seq[File]]("source-directories")
	val ResourceDirectories = SettingKey[Seq[File]]("resource-directories")
	val ClassDirectory = SettingKey[File]("classes-directory")
	val CacheDirectory = SettingKey[File]("cache-directory")
	val LibDirectory = SettingKey[File]("lib-directory")
	val SourceFilter = SettingKey[FileFilter]("source-filter")
	val DefaultExcludes = SettingKey[FileFilter]("default-excludes")
	val Sources = TaskKey[Seq[File]]("sources")
	val ScalacOptions = SettingKey[Seq[String]]("scalac-options")
	val JavacOptions = SettingKey[Seq[String]]("javac-options")

	val WebappDir = SettingKey[File]("webapp-dir")
	val ScalaVersion = SettingKey[String]("scala-version")
	val AutoUpdate = SettingKey[Boolean]("auto-update")

	val CompileInputs = TaskKey[Compile.Inputs]("compile-inputs")
	val ScalaInstance = SettingKey[ScalaInstance]("scala-instance")

	val CompileTask = TaskKey[Analysis]("compile")
	val Compilers = SettingKey[Compile.Compilers]("compilers")

	type Classpath = Seq[Attributed[File]]
	
	val Name = SettingKey[String]("name")
	val NormalizedName = SettingKey[String]("normalized-name")
	val Organization = SettingKey[String]("organization")
	val DefaultConfiguration = SettingKey[Option[Configuration]]("default-configuration")
	val DefaultConfigurationMapping = SettingKey[String]("default-configuration-mapping")

	val Products = TaskKey[Classpath]("products")
	val UnmanagedClasspath = TaskKey[Classpath]("unmanaged-classpath")
	val ManagedClasspath = TaskKey[Classpath]("managed-classpath")
	val InternalDependencyClasspath = TaskKey[Classpath]("internal-dependency-classpath")
	val ExternalDependencyClasspath = TaskKey[Classpath]("external-dependency-classpath")
	val DependencyClasspath = TaskKey[Classpath]("dependency-classpath")
	val FullClasspath = TaskKey[Classpath]("full-classpath")
	
	val IvyConfig = TaskKey[IvyConfiguration]("ivy-configuration")
	val ModuleSettingsTask = TaskKey[ModuleSettings]("module-settings")
	val UnmanagedBase = SettingKey[File]("unmanaged-base")
	val UpdateConfig = SettingKey[UpdateConfiguration]("update-configuration")
	val IvySbtTask = TaskKey[IvySbt]("ivy-sbt")
	val IvyModule = TaskKey[IvySbt#Module]("ivy-module")
	val ClasspathFilter = SettingKey[FileFilter]("classpath-filter")
	val Update = TaskKey[Map[String,Seq[File]]]("update")
	
	val PublishConfig = TaskKey[PublishConfiguration]("publish-configuration")
	val PublishLocalConfig = TaskKey[PublishConfiguration]("publish-local-configuration")
	val MakePomConfig = SettingKey[MakePomConfiguration]("make-pom-configuration")
	val PackageToPublish = TaskKey[Unit]("package-to-publish")
	val DeliverDepends = TaskKey[Unit]("deliver-depends")
	val PublishMavenStyle = SettingKey[Boolean]("publish-maven-style")

	val MakePom = TaskKey[File]("make-pom")
	val Deliver = TaskKey[Unit]("deliver")
	val DeliverLocal = TaskKey[Unit]("deliver-local")
	val Publish = TaskKey[Unit]("publish")
	val PublishLocal = TaskKey[Unit]("publish-local")

	val ModuleName = SettingKey[String]("module-id")
	val Version = SettingKey[String]("version")
	val ProjectID = SettingKey[ModuleID]("project-id")
	val BaseResolvers = SettingKey[Seq[Resolver]]("base-resolvers")
	val ProjectResolver = TaskKey[Resolver]("project-resolver")
	val Resolvers = TaskKey[Seq[Resolver]]("resolvers")
	val OtherResolvers = SettingKey[Seq[Resolver]]("other-resolvers")
	val ModuleConfigurations = SettingKey[Seq[ModuleConfiguration]]("module-configurations")
	val RetrievePattern = SettingKey[String]("retrieve-pattern")
	val RetrieveConfig = SettingKey[Option[RetrieveConfiguration]]("retrieve-configuration")
	val Offline = SettingKey[Boolean]("offline")
	val PathsIvy = SettingKey[IvyPaths]("ivy-paths")
	val LibraryDependencies = SettingKey[Seq[ModuleID]]("library-dependencies")
	val AllDependencies = TaskKey[Seq[ModuleID]]("all-dependencies")
	val ProjectDependencies = TaskKey[Seq[ModuleID]]("project-dependencies")
	val IvyXML = SettingKey[NodeSeq]("ivy-xml")
	val IvyScalaConfig = SettingKey[Option[IvyScala]]("ivy-scala-configuration")
	val IvyValidate = SettingKey[Boolean]("ivy-validate")
	val IvyLoggingLevel = SettingKey[UpdateLogging.Value]("ivy-logging-level")
	val PublishTo = SettingKey[Option[Resolver]]("publish-to")
	val PomFile = SettingKey[File]("pom-file")
	val Artifacts = SettingKey[Seq[Artifact]]("artifacts")
	val ProjectDescriptors = TaskKey[Map[ModuleRevisionId,ModuleDescriptor]]("project-descriptor-map")
	
	// special
	val Data = TaskKey[Settings[Scope]]("settings")
}
object Default
{
	import Path._
	import GlobFilter._
	import Keys._
	import Scope.ThisScope
	implicit def richFileSetting(s: ScopedSetting[File]): RichFileSetting = new RichFileSetting(s)
	implicit def richFilesSetting(s: ScopedSetting[Seq[File]]): RichFilesSetting = new RichFilesSetting(s)
	
	final class RichFileSetting(s: ScopedSetting[File]) extends RichFileBase
	{
		def /(c: String): Apply[File] = s { _ / c }
		protected[this] def map(f: PathFinder => PathFinder) = s(file => finder(f)(file :: Nil))
	}
	final class RichFilesSetting(s: ScopedSetting[Seq[File]]) extends RichFileBase
	{
		def /(s: String): Apply[Seq[File]] = map { _ / s }
		protected[this] def map(f: PathFinder => PathFinder) = s(finder(f))
	}
	sealed abstract class RichFileBase
	{
		def *(filter: FileFilter): Apply[Seq[File]] = map { _ * filter }
		def **(filter: FileFilter): Apply[Seq[File]] = map { _ ** filter }
		protected[this] def map(f: PathFinder => PathFinder): Apply[Seq[File]]
		protected[this] def finder(f: PathFinder => PathFinder): Seq[File] => Seq[File] =
			in => f(in).getFiles.toSeq
	}
	def configSrcSub(key: ScopedSetting[File]): Apply[File] = (key, Config) { (src, conf) => src / nameForSrc(conf.name) }
	def nameForSrc(config: String) = if(config == "compile") "main" else config
	def prefix(config: String) = if(config == "compile") "" else config + "-"
	def toSeq[T](key: ScopedSetting[T]): Apply[Seq[T]] = key( _ :: Nil)

	def extractAnalysis[T](a: Attributed[T]): (T, Analysis) = 
		(a.data, a.metadata get Command.Analysis getOrElse Analysis.Empty)

	def analysisMap[T](cp: Seq[Attributed[T]]): Map[T, Analysis] =
		(cp map extractAnalysis).toMap

	def data[T](in: Seq[Attributed[T]]): Seq[T] = in.map(_.data)

	def core = Seq(
		Name :== "test",
		Version :== "0.1",
		Data <<= EvaluateTask.state map { state => Project.structure(state).data }
	)
	def paths = Seq(
		Base <<= ThisProject(_.base),
		Target <<= Base / "target",
		DefaultExcludes :== (".*"  - ".") || HiddenFileFilter,
		HistoryPath <<= Target(t => Some(t / ".history")),
		CacheDirectory <<= Target / "cache",
		Source <<= Base / "src",
		SourceFilter :== ("*.java" | "*.scala"),
		SourceManaged <<= Base / "src_managed"
	)

	lazy val configPaths = Seq(
		Source <<= configSrcSub( Source in Scope(This,Global,This,This) ),
		SourceManaged <<= configSrcSub(SourceManaged),
		CacheDirectory <<= (CacheDirectory, Config) { _ / _.name },
		ClassDirectory <<= (Target, Config) { (target, conf) => target / (prefix(conf.name) + "classes") },
		Sources <<= (SourceDirectories, SourceFilter, DefaultExcludes) map { (d,f,excl) => d.descendentsExcept(f,excl).getFiles.toSeq },
		ScalaSource <<= Source / "scala",
		JavaSource <<= Source / "java",
		JavaSourceRoots <<= toSeq(JavaSource),
		ResourceDir <<= Source / "resources",
		SourceDirectories <<= (ScalaSource, JavaSourceRoots) { _ +: _ },
		ResourceDirectories <<= toSeq(ResourceDir)
	)
	def addBaseSources = Seq(
		Sources <<= (Sources, Base, SourceFilter, DefaultExcludes) map { (srcs,b,f,excl) => (srcs +++ b * (f -- excl)).getFiles.toSeq }
	)
	lazy val configTasks = Classpaths.configSettings ++ compileTasks
	
	def webPaths = Seq(
		WebappDir <<= Source / "webapp"
	)

	def compileBase = Seq(
		Compilers <<= (ScalaInstance, AppConfig) { (si, app) => Compile.compilers(si)(app, ConsoleLogger()) },
		JavacOptions :== Nil,
		ScalacOptions :== Nil,
		ScalaInstance <<= (AppConfig, ScalaVersion){ (app, version) => sbt.ScalaInstance(version, app.provider.scalaProvider) },
		ScalaVersion <<= AppConfig( _.provider.scalaProvider.version)
	)	
	def compileTasks = Seq(
		CompileTask <<= compileTask,
		CompileInputs <<= compileInputsTask
	)

	def compileTask = (CompileInputs, streams) map { (i,s) => Compile(i,s.log) }
	def compileInputsTask =
		(DependencyClasspath, Sources, JavaSourceRoots, Compilers, JavacOptions, ScalacOptions, CacheDirectory, ClassDirectory, streams) map {
		(cp, sources, javaRoots, compilers, scalacOptions, javacOptions, cacheDirectory, classes, s) =>
			val classpath = classes +: data(cp)
			val analysis = analysisMap(cp)
			val cache = cacheDirectory / "compile"
			Compile.inputs(classpath, sources, classes, scalacOptions, javacOptions, javaRoots, analysis, cache, 100)(compilers, ConsoleLogger())
		}

//	lazy val projectConsole = task { Console.sbtDefault(info.compileInputs, this)(ConsoleLogger()) }
		
	def inConfig(conf: Configuration)(ss: Seq[Setting[_]]): Seq[Setting[_]] =
		Project.transform(Scope.replaceThis(ThisScope.copy(config = Select(conf))), (Config :== conf) +: ss)

	lazy val defaultPaths = paths ++ inConfig(CompileConf)(configPaths ++ addBaseSources) ++ inConfig(TestConf)(configPaths)
	lazy val defaultWebPaths = defaultPaths ++ inConfig(CompileConf)(webPaths)

	lazy val defaultTasks = inConfig(CompileConf)(configTasks) ++ inConfig(TestConf)(configTasks)
	lazy val defaultWebTasks = Nil

	def pluginDefinition = Seq(
		EvaluateTask.PluginDefinition <<= (FullClasspath in CompileConf,CompileTask in CompileConf) map ( (c,a) => (data(c),a) )
	)

	lazy val defaultClasspaths = 	Classpaths.publishSettings ++ Classpaths.baseSettings ++ inConfig(CompileConf)(Classpaths.configSettings) ++ inConfig(TestConf)(Classpaths.configSettings)


	lazy val defaultSettings = core ++ defaultPaths ++ defaultClasspaths ++ defaultTasks ++ compileBase ++ pluginDefinition
	lazy val defaultWebSettings = defaultSettings ++ defaultWebPaths ++ defaultWebTasks
}
object Classpaths
{
		import Path._
		import GlobFilter._
		import Keys._
		import Scope.ThisScope
		import Default._
		import Attributed.{blank, blankSeq}

	def concat[T](a: ScopedTaskable[Seq[T]], b: ScopedTaskable[Seq[T]]): Apply[Task[Seq[T]]] = (a,b) map (_ ++ _)

	val configSettings: Seq[Project.Setting[_]] = Seq(
		ExternalDependencyClasspath <<= concat(UnmanagedClasspath, ManagedClasspath),
		DependencyClasspath <<= concat(InternalDependencyClasspath, ExternalDependencyClasspath),
		FullClasspath <<= concat(DependencyClasspath, Products),
		InternalDependencyClasspath <<= internalDependencies,
		Products <<= makeProducts,
		ManagedClasspath <<= (Config, Update) map { (config, up) => up.getOrElse(config.name, error("Configuration '" + config.name + "' unresolved by 'update'.")) },
		UnmanagedClasspath <<= (Config, UnmanagedBase, ClasspathFilter, DefaultExcludes) map { (config, base, filter, excl) =>
			(base * (filter -- excl) +++ (base / config.name).descendentsExcept(filter, excl)).getFiles.toSeq
		}
	)

	val publishSettings: Seq[Project.Setting[_]] = Seq(
		PublishMavenStyle :== true,
		PackageToPublish :== nop,
		DeliverDepends := (PublishMavenStyle, MakePom.setting, PackageToPublish.setting) { (mavenStyle, makePom, ptp) => if(mavenStyle) makePom else ptp },
		MakePom <<= (IvyModule, MakePomConfig, PackageToPublish) map { (ivyModule, makePomConfig, _) => IvyActions.makePom(ivyModule, makePomConfig); makePomConfig.file },
		Deliver <<= deliver(PublishConfig),
		DeliverLocal <<= deliver(PublishLocalConfig),
		Publish <<= publish(PublishConfig, Deliver),
		PublishLocal <<= publish(PublishLocalConfig, DeliverLocal)
	)
	val baseSettings: Seq[Project.Setting[_]] = Seq(
		UnmanagedBase <<= Base / "lib",
		NormalizedName <<= Name(StringUtilities.normalize),
		Organization :== NormalizedName,
		ClasspathFilter :== "*.jar",
		Resolvers <<= (ProjectResolver,BaseResolvers).map( (pr,rs) => pr +: Resolver.withDefaultResolvers(rs)),
		Offline :== false,
		ModuleName :== NormalizedName,
		DefaultConfiguration :== Some(Configurations.Compile),
		DefaultConfigurationMapping <<= DefaultConfiguration{ case Some(d) => "*->" + d.name; case None => "*->*" },
		PathsIvy <<= Base(base => new IvyPaths(base, None)),
		OtherResolvers :== Nil,
		ProjectResolver <<= projectResolver,
		ProjectDependencies <<= projectDependencies,
		LibraryDependencies :== Nil,
		AllDependencies <<= concat(ProjectDependencies,LibraryDependencies),
		IvyLoggingLevel :== UpdateLogging.Quiet,
		IvyXML :== NodeSeq.Empty,
		IvyValidate :== false,
		IvyScalaConfig :== None,
		ModuleConfigurations :== Nil,
		PublishTo :== None,
		PomFile <<= (Target, Version, ModuleName)( (target, version, module) => target / (module + "-" + version + ".pom") ),
		Artifacts <<= ModuleName(name => Artifact(name, "jar", "jar") :: Nil),
		ProjectID <<= (Organization,ModuleName,Version,Artifacts){ (org,module,version,as) => ModuleID(org, module, version).cross(true).artifacts(as : _*) },
		BaseResolvers :== Nil,
		ProjectDescriptors <<= depMap,
		RetrievePattern :== "[type]/[organisation]/[module]/[artifact](-[revision])(-[classifier]).[ext]",
		UpdateConfig <<= (RetrieveConfig, IvyLoggingLevel)((conf,level) => new UpdateConfiguration(conf, level) ),
		RetrieveConfig :== None, //Some(new RetrieveConfiguration(managedDependencyPath asFile, retrievePattern, true))
		IvyConfig <<= (Resolvers, PathsIvy, OtherResolvers, ModuleConfigurations, Offline, AppConfig) map { (rs, paths, otherResolvers, moduleConfigurations, offline, app) =>
			// todo: pass logger from streams directly to IvyActions
			val lock = app.provider.scalaProvider.launcher.globalLock
			new InlineIvyConfiguration(paths, rs, otherResolvers, moduleConfigurations, offline, Some(lock), ConsoleLogger())
		},
		ModuleSettingsTask <<= (ProjectID, AllDependencies, IvyXML, ThisProject, DefaultConfiguration, IvyScalaConfig, IvyValidate) map {
			(pid, deps, ivyXML, project, defaultConf, ivyScala, validate) => new InlineConfiguration(pid, deps, ivyXML, project.configurations, defaultConf, ivyScala, validate)
		},
		MakePomConfig <<= PomFile(pomFile => makePomConfiguration(pomFile)),
		PublishConfig <<= (Target, PublishTo, IvyLoggingLevel) map { (outputDirectory, publishTo, level) => publishConfiguration( publishPatterns(outputDirectory), resolverName = getPublishTo(publishTo).name, logging = level) },
		PublishLocalConfig <<= (Target, IvyLoggingLevel) map { (outputDirectory, level) => publishConfiguration( publishPatterns(outputDirectory, true), logging = level ) },
		IvySbtTask <<= IvyConfig map { conf => new IvySbt(conf) },
		IvyModule <<= (IvySbtTask, ModuleSettingsTask) map { (ivySbt, settings) => new ivySbt.Module(settings) },
		Update <<= (IvyModule, UpdateConfig, CacheDirectory, streams) map { (ivyModule, updateConfig, cacheDirectory, s) =>
			cachedUpdate(cacheDirectory / "update", ivyModule, updateConfig, s.log)
		}
	)


	def deliver(config: TaskKey[PublishConfiguration]): Apply[Task[Unit]] =
		(IvyModule, config, DeliverDepends) map { (ivyModule, config, _) => IvyActions.deliver(ivyModule, config) }
	def publish(config: TaskKey[PublishConfiguration], deliverKey: TaskKey[_]): Apply[Task[Unit]] =
		(IvyModule, config, deliverKey) map { (ivyModule, config, _) => IvyActions.publish(ivyModule, config) }

		import Cache._
		import Types._
		import CacheIvy.{classpathFormat, publishIC, updateIC}

	def cachedUpdate(cacheFile: File, module: IvySbt#Module, config: UpdateConfiguration, log: Logger): Map[String, Seq[File]] =
	{
		implicit val updateCache = updateIC
		val work = (_:  IvyConfiguration :+: ModuleSettings :+: UpdateConfiguration :+: HNil) match { case conf :+: settings :+: config :+: HNil =>
			log.info("Updating...")
			val r = IvyActions.update(module, config)
			log.info("Done updating.")
			r
		}
		val f = cached(cacheFile)(work)
		f(module.owner.configuration :+: module.moduleSettings :+: config :+: HNil)
	}
/*
	// can't cache deliver/publish easily since files involved are hidden behind patterns.  publish will be difficult to verify target-side anyway
	def cachedPublish(cacheFile: File)(g: (IvySbt#Module, PublishConfiguration) => Unit, module: IvySbt#Module, config: PublishConfiguration) => Unit =
	{ case module :+: config :+: HNil =>
	/*	implicit val publishCache = publishIC
		val f = cached(cacheFile) { (conf: IvyConfiguration, settings: ModuleSettings, config: PublishConfiguration) =>*/
		    g(module, config)
		/*}
		f(module.owner.configuration :+: module.moduleSettings :+: config :+: HNil)*/
	}*/
	def makePomConfiguration(file: File, configurations: Option[Iterable[Configuration]] = None, extra: NodeSeq = NodeSeq.Empty, process: XNode => XNode = n => n, filterRepositories: MavenRepository => Boolean = _ => true) = 
		new MakePomConfiguration(file, configurations, extra, process, filterRepositories)

	def getPublishTo(repo: Option[Resolver]): Resolver = repo getOrElse error("Repository for publishing is not specified.")

	def publishConfiguration(patterns: PublishPatterns, resolverName: String = "local", status: String = "release", logging: UpdateLogging.Value = UpdateLogging.DownloadOnly) =
	    new PublishConfiguration(patterns, status, resolverName, None, logging)

	def publishPatterns(outputPath: Path, publishIvy: Boolean = false): PublishPatterns =
	{
		val deliverPattern = (outputPath / "[artifact]-[revision](-[classifier]).[ext]").absolutePath
		val srcArtifactPatterns: Seq[String] =
		{
			val pathPatterns =
				(outputPath / "[artifact]-[revision]-[type](-[classifier]).[ext]") ::
				(outputPath / "[artifact]-[revision](-[classifier]).[ext]") ::
				Nil
			pathPatterns.map(_.absolutePath)
		}
		new PublishPatterns( if(publishIvy) Some(deliverPattern) else None, srcArtifactPatterns)
	}

	def projectDependencies =
		(ThisProject, Data) map { (p, data) =>
			p.dependencies flatMap { dep => (ProjectID in dep.project) get data map { _.copy(configurations = dep.configuration) } }
		}

	def depMap: Apply[Task[Map[ModuleRevisionId, ModuleDescriptor]]] =
		(ThisProject, ThisProjectRef, Data) flatMap { (root, rootRef, data) =>
			val dependencies = (p: (ProjectRef, Project)) => p._2.dependencies.flatMap(pr => ThisProject in pr.project get data map { (pr.project, _) })
			depMap(Dag.topologicalSort((rootRef,root))(dependencies).dropRight(1), data)
		}

	def depMap(projects: Seq[(ProjectRef,Project)], data: Settings[Scope]): Task[Map[ModuleRevisionId, ModuleDescriptor]] =
		projects.flatMap { case (p,_) => IvyModule in p get data }.join.map { mods =>
			(mods.map{ mod =>
				val md = mod.moduleDescriptor
				(md.getModuleRevisionId, md)
			}).toMap
		}

	def projectResolver: Apply[Task[Resolver]] =
		ProjectDescriptors map { m =>
			new RawRepository(new ProjectResolver("inter-project", m))
		}

	def analyzed[T](data: T, analysis: Analysis) = Attributed.blank(data).put(Command.Analysis, analysis)
	def makeProducts: Apply[Task[Classpath]] =
		(CompileTask, CompileInputs) map { (analysis, i) => analyzed(i.config.classesDirectory, analysis) :: Nil }

	def internalDependencies: Apply[Task[Classpath]] =
		(ThisProjectRef, ThisProject, Config, Data) flatMap internalDependencies0

	def internalDependencies0(projectRef: ProjectRef, project: Project, conf: Configuration, data: Settings[Scope]): Task[Classpath] =
	{
			import java.util.LinkedHashSet
			import collection.JavaConversions.asScalaSet
		val visited = asScalaSet(new LinkedHashSet[(ProjectRef,String)])
		def visit(p: ProjectRef, project: Project, c: Configuration)
		{
			val applicableConfigs = allConfigs(c)
			for(ac <- applicableConfigs) // add all configurations in this project
				visited add (p, ac.name)
			val masterConfs = configurationNames(project)

			for( Project.ClasspathDependency(dep, confMapping) <- project.dependencies)
			{
				val depProject = ThisProject in dep get data getOrElse error("Invalid project: " + dep)
				val mapping = mapped(confMapping, masterConfs, configurationNames(depProject), "compile", "*->compile")
				// map master configuration 'c' and all extended configurations to the appropriate dependency configuration
				for(ac <- applicableConfigs; depConfName <- mapping(ac.name))
				{
					val depConf = configuration(dep, depProject, depConfName)
					if( ! visited( (dep, depConfName) ) )
						visit(dep, depProject, depConf)
				}
			}
		}
		visit(projectRef, project, conf)

		val productsTasks = asScalaSet(new LinkedHashSet[Task[Classpath]])
		for( (dep, c) <- visited )
			if( (dep != projectRef) || conf.name != c )
				productsTasks += products(dep, c, data)

		(productsTasks.toSeq.join).map(_.flatten)
	}
	
	def mapped(confString: Option[String], masterConfs: Seq[String], depConfs: Seq[String], default: String, defaultMapping: String): String => Seq[String] =
	{
		lazy val defaultMap = parseMapping(defaultMapping, masterConfs, depConfs, _ :: Nil)
		parseMapping(confString getOrElse default, masterConfs, depConfs, defaultMap)
	}
	def parseMapping(confString: String, masterConfs: Seq[String], depConfs: Seq[String], default: String => Seq[String]): String => Seq[String] =
		union(confString.split(";") map parseSingleMapping(masterConfs, depConfs, default))
	def parseSingleMapping( masterConfs: Seq[String], depConfs: Seq[String], default: String => Seq[String])(confString: String): String => Seq[String] =
	{
		val ms: Seq[(String,Seq[String])] =
			trim(confString.split("->",2)) match {
				case x :: Nil => for(a <- parseList(x, masterConfs)) yield (a,default(a))
				case x :: y :: Nil => val target = parseList(y, depConfs); for(a <- parseList(x, masterConfs)) yield (a,target)
				case _ => error("Invalid configuration '" + confString + "'") // shouldn't get here
			}
		val m = ms.toMap
		s => m.getOrElse(s, Nil)
	}

	def union[A,B](maps: Seq[A => Seq[B]]): A => Seq[B] =
		a => (Seq[B]() /: maps) { _ ++ _(a) } distinct;

	def configurationNames(p: Project): Seq[String] = p.configurations.map( _.name)
	def parseList(s: String, allConfs: Seq[String]): Seq[String] = (trim(s split ",") flatMap replaceWildcard(allConfs)).distinct
	def replaceWildcard(allConfs: Seq[String])(conf: String): Seq[String] =
		if(conf == "") Nil else if(conf == "*") allConfs else conf :: Nil
	
	private def trim(a: Array[String]): List[String] = a.toList.map(_.trim)
	def missingConfiguration(in: String, conf: String) =
		error("Configuration '" + conf + "' not defined in '" + in + "'")
	def allConfigs(conf: Configuration): Seq[Configuration] =
		Dag.topologicalSort(conf)(_.extendsConfigs)

	def configuration(ref: ProjectRef, dep: Project, conf: String): Configuration =
		dep.configurations.find(_.name == conf) getOrElse missingConfiguration(Project display ref, conf)
	def products(dep: ProjectRef, conf: String, data: Settings[Scope]): Task[Classpath] =
		Products in (dep, ConfigKey(conf)) get data getOrElse const(Nil)
	def defaultConfiguration(p: ProjectRef, data: Settings[Scope]): Configuration =
		flatten(DefaultConfiguration in p get data) getOrElse Configurations.Default
	def flatten[T](o: Option[Option[T]]): Option[T] = o flatMap identity
}