/* sbt -- Simple Build Tool
 * Copyright 2010 Mark Harrah
 */
package sbt
package compiler

import inc._

	import scala.annotation.tailrec
	import java.io.File
	import classpath.ClasspathUtilities
	import classfile.Analyze
	import inc.Locate.DefinesClass
	import CompileSetup._
	import sbinary.DefaultProtocol.{ immutableMapFormat, immutableSetFormat, StringFormat }

	import xsbti.{ Reporter, AnalysisCallback }
	import xsbti.api.Source
	import xsbti.compile.{CompileOrder, DependencyChanges, GlobalsCache, Output, SingleOutput, MultipleOutput, CompileProgress}
	import CompileOrder.{JavaThenScala, Mixed, ScalaThenJava}

final class CompileConfiguration(val sources: Seq[File], val classpath: Seq[File],
	val previousAnalysis: Analysis, val previousSetup: Option[CompileSetup], val currentSetup: CompileSetup, val progress: Option[CompileProgress], val getAnalysis: File => Option[Analysis], val definesClass: DefinesClass,
	val reporter: Reporter, val compiler: AnalyzingCompiler, val javac: xsbti.compile.JavaCompiler, val cache: GlobalsCache)

class AggressiveCompile(cacheFile: File)
{
	def apply(compiler: AnalyzingCompiler, javac: xsbti.compile.JavaCompiler, sources: Seq[File], classpath: Seq[File], output: Output, cache: GlobalsCache, progress: Option[CompileProgress] = None, options: Seq[String] = Nil, javacOptions: Seq[String] = Nil, analysisMap: File => Option[Analysis] = { _ => None }, definesClass: DefinesClass = Locate.definesClass _, reporter: Reporter, compileOrder: CompileOrder = Mixed, skip: Boolean = false)(implicit log: Logger): Analysis =
	{
		val setup = new CompileSetup(output, new CompileOptions(options, javacOptions), compiler.scalaInstance.actualVersion, compileOrder)
		compile1(sources, classpath, setup, progress, store, analysisMap, definesClass, compiler, javac, reporter, skip, cache)
	}

	def withBootclasspath(args: CompilerArguments, classpath: Seq[File]): Seq[File] =
		args.bootClasspathFor(classpath) ++ args.finishClasspath(classpath)

	def compile1(sources: Seq[File], classpath: Seq[File], setup: CompileSetup, progress: Option[CompileProgress], store: AnalysisStore, analysis: File => Option[Analysis], definesClass: DefinesClass, compiler: AnalyzingCompiler, javac: xsbti.compile.JavaCompiler, reporter: Reporter, skip: Boolean, cache: GlobalsCache)(implicit log: Logger): Analysis =
	{
		val (previousAnalysis, previousSetup) = extract(store.get())
		if(skip)
			previousAnalysis
		else {
			val config = new CompileConfiguration(sources, classpath, previousAnalysis, previousSetup, setup, progress, analysis, definesClass, reporter, compiler, javac, cache)
			val (modified, result) = compile2(config)
			if(modified)
				store.set(result, setup)
			result
		}
	}
	def compile2(config: CompileConfiguration)(implicit log: Logger, equiv: Equiv[CompileSetup]): (Boolean, Analysis) =
	{
		import config._
		import currentSetup._
		val absClasspath = classpath.map(_.getCanonicalFile)
		val apiOption = (api: Either[Boolean, Source]) => api.right.toOption
		val cArgs = new CompilerArguments(compiler.scalaInstance, compiler.cp)
		val searchClasspath = explicitBootClasspath(options.options) ++ withBootclasspath(cArgs, absClasspath)
		val entry = Locate.entry(searchClasspath, definesClass)
		
		val compile0 = (include: Set[File], changes: DependencyChanges, callback: AnalysisCallback) => {
			val outputDirs = outputDirectories(output)
			outputDirs foreach (IO.createDirectory)
			val incSrc = sources.filter(include)
			val (javaSrcs, scalaSrcs) = incSrc partition javaOnly
			logInputs(log, javaSrcs.size, scalaSrcs.size, outputDirs)
			def compileScala() =
				if(!scalaSrcs.isEmpty)
				{
					val sources = if(order == Mixed) incSrc else scalaSrcs
					val arguments = cArgs(Nil, absClasspath, None, options.options)
					timed("Scala compilation", log) {
						compiler.compile(sources, changes, arguments, output, callback, reporter, cache, log, progress)
					}
				}
			def compileJava() =
				if(!javaSrcs.isEmpty)
				{
					import Path._
					@tailrec def ancestor(f1: File, f2: File): Boolean =
						if (f2 eq null) false	else
							if (f1 == f2) true else ancestor(f1, f2.getParentFile)

					val chunks: Map[Option[File], Seq[File]] = output match {
						case single: SingleOutput => Map(Some(single.outputDirectory) -> javaSrcs)
						case multi: MultipleOutput =>
							javaSrcs groupBy { src =>
								multi.outputGroups find {out => ancestor(out.sourceDirectory, src)} map (_.outputDirectory)
							}
					}
					chunks.get(None) foreach { srcs =>
						log.error("No output directory mapped for: " + srcs.map(_.getAbsolutePath).mkString(","))
				  }
					val memo = for ((Some(outputDirectory), srcs) <- chunks) yield {
						val classesFinder = PathFinder(outputDirectory) ** "*.class"
						(classesFinder, classesFinder.get, srcs)
					}

					val loader = ClasspathUtilities.toLoader(searchClasspath)
					timed("Java compilation", log) {
						javac.compile(javaSrcs.toArray, absClasspath.toArray, output, options.javacOptions.toArray, log)
					}

					def readAPI(source: File, classes: Seq[Class[_]]) { callback.api(source, ClassToAPI(classes)) }

					timed("Java analysis", log) {
						for ((classesFinder, oldClasses, srcs) <- memo) {
							val newClasses = Set(classesFinder.get: _*) -- oldClasses
							Analyze(newClasses.toSeq, srcs, log)(callback, loader, readAPI)
						}
					}
				}
			if(order == JavaThenScala) { compileJava(); compileScala() } else { compileScala(); compileJava() }
		}
		
		val sourcesSet = sources.toSet
		val analysis = previousSetup match {
			case Some(previous) if equiv.equiv(previous, currentSetup) => previousAnalysis
			case _ => Incremental.prune(sourcesSet, previousAnalysis)
		}
		IncrementalCompile(sourcesSet, entry, compile0, analysis, getAnalysis, output, log)
	}
	private[this] def outputDirectories(output: Output): Seq[File] = output match {
		case single: SingleOutput => List(single.outputDirectory)
		case mult: MultipleOutput => mult.outputGroups map (_.outputDirectory)
	}
	private[this] def timed[T](label: String, log: Logger)(t: => T): T =
	{
		val start = System.nanoTime
		val result = t
		val elapsed = System.nanoTime - start
		log.debug(label + " took " + (elapsed/1e9) + " s")
		result
	}
	private[this] def logInputs(log: Logger, javaCount: Int, scalaCount: Int, outputDirs: Seq[File])
	{
		val scalaMsg = Analysis.counted("Scala source", "", "s", scalaCount)
		val javaMsg = Analysis.counted("Java source", "", "s", javaCount)
		val combined = scalaMsg ++ javaMsg
		if(!combined.isEmpty)
			log.info(combined.mkString("Compiling ", " and ", " to " + outputDirs.map(_.getAbsolutePath).mkString(",") + "..."))
	}
	private def extract(previous: Option[(Analysis, CompileSetup)]): (Analysis, Option[CompileSetup]) =
		previous match
		{
			case Some((an, setup)) => (an, Some(setup))
			case None => (Analysis.Empty, None)
		}
	def javaOnly(f: File) = f.getName.endsWith(".java")

	private[this] def explicitBootClasspath(options: Seq[String]): Seq[File] =
		options.dropWhile(_ != CompilerArguments.BootClasspathOption).drop(1).take(1).headOption.toList.flatMap(IO.parseClasspath)

	import AnalysisFormats._
	val store = AggressiveCompile.staticCache(cacheFile, AnalysisStore.sync(AnalysisStore.cached(FileBasedStore(cacheFile))))
}
object AggressiveCompile
{
		import collection.mutable
		import java.lang.ref.{Reference,SoftReference}
	private[this] val cache = new collection.mutable.HashMap[File, Reference[AnalysisStore]]
	private def staticCache(file: File, backing: => AnalysisStore): AnalysisStore =
		synchronized {
			cache get file flatMap { ref => Option(ref.get) } getOrElse {
				val b = backing
				cache.put(file, new SoftReference(b))
				b
			}
		}

	def directOrFork(instance: ScalaInstance, cpOptions: ClasspathOptions, javaHome: Option[File]): JavaTool =
		if(javaHome.isDefined)
			JavaCompiler.fork(cpOptions, instance)(forkJavac(javaHome))
		else
			JavaCompiler.directOrFork(cpOptions, instance)(forkJavac(None))

	def forkJavac(javaHome: Option[File]): JavaCompiler.Fork =
	{
		import Path._
		def exec(jc: JavacContract) = javaHome match { case None => jc.name; case Some(jh) => (jh / "bin" / jc.name).absolutePath }
		(contract: JavacContract, args: Seq[String], log: Logger) => {
			log.debug("Forking " + contract.name + ": " + exec(contract) + " " + args.mkString(" "))
			val javacLogger = new JavacLogger(log)
			var exitCode = -1
			try {
				exitCode = Process(exec(contract), args) ! javacLogger
			} finally {
				javacLogger.flush(exitCode)
			}
			exitCode
		}
	}
}

private[sbt] class JavacLogger(log: Logger) extends ProcessLogger {
  import scala.collection.mutable.ListBuffer
  import Level.{Info, Warn, Error, Value => LogLevel}

  private val msgs: ListBuffer[(LogLevel, String)] = new ListBuffer()

  def info(s: => String): Unit =
    synchronized { msgs += ((Info, s)) }

  def error(s: => String): Unit =
    synchronized { msgs += ((Error, s)) }

  def buffer[T](f: => T): T = f

  private def print(desiredLevel: LogLevel)(t: (LogLevel, String)) = t match {
    case (Info, msg) => log.info(msg)
    case (Error, msg) => log.log(desiredLevel, msg)
  }

  def flush(exitCode: Int): Unit = {
    val level = if (exitCode == 0) Warn else Error
    msgs foreach print(level)
    msgs.clear()
  }
}
