/* sbt -- Simple Build Tool
 * Copyright 2011 Mark Harrah
 */
package sbt

	import java.io.File
	import java.net.URI
	import compiler.{Eval, EvalImports}
	import complete.DefaultParsers.validID
	import Compiler.Compilers
	import Project.{ScopedKey, Setting}
	import Keys.Streams
	import scala.annotation.tailrec

// name is more like BuildDefinition, but that is too long
trait Build
{
	def projects: Seq[Project]
	def settings: Seq[Setting[_]] = Defaults.buildCore
}
trait Plugin
{
	def settings: Seq[Project.Setting[_]] = Nil
}

object Build
{
	def default(base: File): Build = new Build { def projects = defaultProject("default", base) :: Nil }
	def defaultProject(id: String, base: File): Project = Project(id, base)

	def data[T](in: Seq[Attributed[T]]): Seq[T] = in.map(_.data)
	def analyzed(in: Seq[Attributed[_]]): Seq[inc.Analysis] = in.flatMap{ _.metadata.get(Keys.analysis) }
}
object RetrieveUnit
{
	def apply(tempDir: File, base: URI): File =
	{
		lazy val tmp = temporary(tempDir, base)
		base.getScheme match
		{
			case "file" => val f = new File(base); if(f.isDirectory) f else error("Not a directory: '" + base + "'")
			case "git" => gitClone(base, tmp); tmp
			case "http" | "https" => downloadAndExtract(base, tmp); tmp
			case _ => error("Unknown scheme in '" + base + "'")
		}
	}
	def downloadAndExtract(base: URI, tempDir: File): Unit = if(!tempDir.exists) IO.unzipURL(base.toURL, tempDir)
	def temporary(tempDir: File, uri: URI): File = new File(tempDir, hash(uri))
	def hash(uri: URI): String = Hash.toHex(Hash(uri.toASCIIString))

	import Process._
	def gitClone(base: URI, tempDir: File): Unit =
		if(!tempDir.exists)  ("git" :: "clone" :: base.toASCIIString :: tempDir.getAbsolutePath :: Nil) ! ;
}
object EvaluateConfigurations
{
	def apply(eval: Eval, srcs: Seq[File], imports: Seq[String]): Seq[Setting[_]] =
		srcs flatMap { src =>  evaluateConfiguration(eval, src, imports) }
	def evaluateConfiguration(eval: Eval, src: File, imports: Seq[String]): Seq[Setting[_]] =
		evaluateConfiguration(eval, src.getPath, IO.readLines(src), imports)
	def evaluateConfiguration(eval: Eval, name: String, lines: Seq[String], imports: Seq[String]): Seq[Setting[_]] =
	{
		val (importExpressions, settingExpressions) = splitExpressions(name, lines)
		for((settingExpression,line) <- settingExpressions) yield
			evaluateSetting(eval, name, (imports.map(s => (s, -1)) ++ importExpressions), settingExpression, line)
	}

	def evaluateSetting(eval: Eval, name: String, imports: Seq[(String,Int)], expression: String, line: Int): Setting[_] =
	{
		val result = try {
			eval.eval(expression, imports = new EvalImports(imports, name), srcName = name, tpeName = Some("sbt.Project.Setting[_]"), line = line)
		} catch {
			case e: sbt.compiler.EvalException => throw new MessageOnlyException(e.getMessage)
		}
		result.value.asInstanceOf[Setting[_]]
	}
	private[this] def fstS(f: String => Boolean): ((String,Int)) => Boolean = { case (s,i) => f(s) }
	def splitExpressions(name: String, lines: Seq[String]): (Seq[(String,Int)], Seq[(String,Int)]) =
	{
		val blank = (_: String).trim.isEmpty
		val importOrBlank = fstS(t => blank(t) || (t.trim startsWith "import "))

		val (imports, settings) = lines.zipWithIndex span importOrBlank
		(imports filterNot fstS(blank), groupedLines(settings, blank))
	}
	def groupedLines(lines: Seq[(String,Int)], delimiter: String => Boolean): Seq[(String,Int)] =
	{
		val fdelim = fstS(delimiter)
		@tailrec def group0(lines: Seq[(String,Int)], accum: Seq[(String,Int)]): Seq[(String,Int)] =
			if(lines.isEmpty) accum.reverse
			else
			{
				val start = lines dropWhile fstS(delimiter)
				val (next, tail) = start.span { case (s,_) => !delimiter(s) }
				val grouped = if(next.isEmpty) accum else (next.map(_._1).mkString("\n"), next.head._2) +: accum
				group0(tail, grouped)
			}
		group0(lines, Nil)
	}
}
object Index
{
	def taskToKeyMap(data: Settings[Scope]): Map[Task[_], ScopedKey[Task[_]]] =
	{
		// AttributeEntry + the checked type test 'value: Task[_]' ensures that the cast is correct.
		//  (scalac couldn't determine that 'key' is of type AttributeKey[Task[_]] on its own and a type match still required the cast)
		val pairs = for( scope <- data.scopes; AttributeEntry(key, value: Task[_]) <- data.data(scope).entries ) yield
			(value, ScopedKey(scope, key.asInstanceOf[AttributeKey[Task[_]]])) // unclear why this cast is needed even with a type test in the above filter
		pairs.toMap[Task[_], ScopedKey[Task[_]]]
	}
	def stringToKeyMap(settings: Settings[Scope]): Map[String, AttributeKey[_]] =
	{
		val multiMap = settings.data.values.flatMap(_.keys).toList.distinct.groupBy(_.label)
		val duplicates = multiMap collect { case (k, x1 :: x2 :: _) => k }
		if(duplicates.isEmpty)
			multiMap.collect { case (k, v) if validID(k) => (k, v.head) } toMap;
		else
			error(duplicates.mkString("AttributeKey ID collisions detected for '", "', '", "'"))
	}
}
object BuildStreams
{
		import Load.{BuildStructure, LoadedBuildUnit}
		import Project.display
		import std.{TaskExtra,Transform}
	
	val GlobalPath = "$global"
	val BuildUnitPath = "$build"

	def mkStreams(units: Map[URI, LoadedBuildUnit], root: URI, data: Settings[Scope], logRelativePath: Seq[String] = defaultLogPath): Streams =
		std.Streams( path(units, root, logRelativePath), display, LogManager.construct(data) )
		
	def defaultLogPath = "target" :: "streams" :: Nil

	def path(units: Map[URI, LoadedBuildUnit], root: URI, sep: Seq[String])(scoped: ScopedKey[_]): File =
	{
		val (base, sub) = projectPath(units, root, scoped)
		resolvePath(base, sep ++ sub ++ nonProjectPath(scoped) )
	}
	def resolvePath(base: File, components: Seq[String]): File =
		(base /: components)( (b,p) => new File(b,p) )

	def pathComponent[T](axis: ScopeAxis[T], scoped: ScopedKey[_], label: String)(show: T => String): String =
		axis match
		{
			case Global => GlobalPath
			case This => error("Unresolved This reference for " + label + " in " + display(scoped))
			case Select(t) => show(t)
		}
	def nonProjectPath[T](scoped: ScopedKey[T]): Seq[String] =
	{
		val scope = scoped.scope
		pathComponent(scope.config, scoped, "config")(_.name) ::
		pathComponent(scope.task, scoped, "task")(_.label) ::
		pathComponent(scope.extra, scoped, "extra")(_ => error("Unimplemented")) ::
		Nil
	}
	def projectPath(units: Map[URI, LoadedBuildUnit], root: URI, scoped: ScopedKey[_]): (File, Seq[String]) =
		scoped.scope.project match
		{
			case Global => (units(root).localBase, GlobalPath :: Nil)
			case Select(BuildRef(uri)) => (units(uri).localBase, BuildUnitPath :: Nil)
			case Select(ProjectRef(uri, id)) => (units(uri).defined(id).base, Nil)
			case Select(pr) => error("Unresolved project reference (" + pr + ") in " + display(scoped))
			case This => error("Unresolved project reference (This) in " + display(scoped))
		}
}
object BuildPaths
{
	import Path._
	import GlobFilter._

	def defaultStaging = Path.userHome / ".sbt" / "staging"
	def defaultGlobalPlugins = Path.userHome / ".sbt" / "plugins"
	
	def definitionSources(base: File): Seq[File] = (base * "*.scala").getFiles
	def configurationSources(base: File): Seq[File] = (base * "*.sbt").getFiles
	def pluginDirectory(definitionBase: Path) = definitionBase / "plugins"

	def evalOutputDirectory(base: Path) = outputDirectory(base) / "config-classes"
	def outputDirectory(base: Path) = base / "target"
	def buildOutputDirectory(base: Path, compilers: Compilers) = crossPath(outputDirectory(base), compilers.scalac.scalaInstance)

	def projectStandard(base: Path) = base / "project"
	def projectHidden(base: Path) = base / ".sbt"
	def selectProjectDir(base: Path) =
	{
		val a = projectHidden(base)
		val b = projectStandard(base)
		if(a.exists) a else b
	}

	def crossPath(base: File, instance: ScalaInstance): File = base / ("scala_" + instance.version)
}