package sbt

import java.io.File
import org.scalacheck.{Arbitrary, Gen, Prop, Properties}
import Prop._

import Process._

object ProcessSpecification extends Properties("Process I/O")
{
	implicit val exitCodeArb: Arbitrary[Array[Byte]] = Arbitrary(
		for(size <- Gen.choose(0, 10);
			l <- Gen.listOfN[Byte](size, Arbitrary.arbByte.arbitrary))
		yield
			l.toArray
	)

	/*property("Correct exit code") = forAll( (exitCode: Byte) => checkExit(exitCode))
	property("#&& correct") = forAll( (exitCodes: Array[Byte]) => checkBinary(exitCodes)(_ #&& _)(_ && _))
	property("#|| correct") = forAll( (exitCodes: Array[Byte]) => checkBinary(exitCodes)(_ #|| _)(_ || _))
	property("### correct") = forAll( (exitCodes: Array[Byte]) => checkBinary(exitCodes)(_ ### _)( (x,latest) => latest))*/
	property("Pipe to output file") = forAll( (data: Array[Byte]) => checkFileOut(data))
	property("Pipe from input file") = forAll( (data: Array[Byte]) => checkFileIn(data))
	property("Pipe to process") = forAll( (data: Array[Byte]) => checkPipe(data))
	property("Pipe to process ignores input exit code") = forAll( (data: Array[Byte], code: Byte) => checkPipeExit(data, code))
	property("Pipe from input file to bad process preserves correct exit code.") = forAll( (data: Array[Byte], code: Byte) => checkFileInExit(data, code))
	property("Pipe to output file from bad process preserves correct exit code.") = forAll( (data: Array[Byte], code: Byte) => checkFileOutExit(data, code))

	private def checkBinary(codes: Array[Byte])(reduceProcesses: (ProcessBuilder, ProcessBuilder) => ProcessBuilder)(reduceExit: (Boolean, Boolean) => Boolean) =
	{
		(codes.length > 1) ==>
		{
			val unsignedCodes = codes.map(unsigned)
			val exitCode = unsignedCodes.map(code => Process(process("sbt.exit " + code))).reduceLeft(reduceProcesses) !
			val expectedExitCode = unsignedCodes.map(toBoolean).reduceLeft(reduceExit)
			toBoolean(exitCode) == expectedExitCode
		}
	}
	private def toBoolean(exitCode: Int) = exitCode == 0
	private def checkExit(code: Byte) =
	{
		val exitCode = unsigned(code)
		(process("sbt.exit " + exitCode) !) == exitCode
	}
	private def checkFileOut(data: Array[Byte]) =
	{
		withData(data) { (temporaryFile, temporaryFile2) =>
			val catCommand = process("sbt.cat " + temporaryFile.getAbsolutePath)
			catCommand #> temporaryFile2
		}
	}
	private def checkFileIn(data: Array[Byte]) =
	{
		withData(data) { (temporaryFile, temporaryFile2) =>
			val catCommand = process("sbt.cat")
			temporaryFile #> catCommand #> temporaryFile2
		}
	}
	private def checkPipe(data: Array[Byte]) =
	{
		withData(data) { (temporaryFile, temporaryFile2) =>
			val catCommand = process("sbt.cat")
			temporaryFile #> catCommand #| catCommand #> temporaryFile2
		}
	}
	private def checkPipeExit(data: Array[Byte], code: Byte) =
		withTempFiles { (a,b) =>
			IO.write(a, data)
			val catCommand = process("sbt.cat")
			val exitCommand = process(s"sbt.exit $code")
			val exit = (a #> exitCommand #| catCommand #> b).!
			(s"Exit code: $exit") |:
			(s"Output file length: ${b.length}") |:
				(exit == 0) &&
				(b.length == 0)
		}

	private def checkFileOutExit(data: Array[Byte], exitCode: Byte) =
		withTempFiles { (a,b) =>
			IO.write(a, data)
			val code = unsigned(exitCode)
			val command = process(s"sbt.exit $code")
			val exit = (a #> command #> b).!
			(s"Exit code: $exit, expected: $code") |:
			(s"Output file length: ${b.length}") |:
				(exit == code) &&
				(b.length == 0)
		}

	private def checkFileInExit(data: Array[Byte], exitCode: Byte) =
		withTempFiles { (a,b) =>
			IO.write(a, data)
			val code = unsigned(exitCode)
			val command = process(s"sbt.exit $code")
			val exit = (a #> command).!
			(s"Exit code: $exit, expected: $code") |:
				(exit == code)
		}

	private def temp() = File.createTempFile("sbt", "")
	private def withData(data: Array[Byte])(f: (File, File) => ProcessBuilder) =
		withTempFiles { (a, b) =>
			IO.write(a, data)
			val process = f(a, b)
			( process ! ) == 0 && sameFiles(a, b)
		}
	private def sameFiles(a: File, b: File) =
		IO.readBytes(a) sameElements IO.readBytes(b)

	private def withTempFiles[T](f: (File, File) => T): T =
	{
		val temporaryFile1 = temp()
		val temporaryFile2 = temp()
		try f(temporaryFile1, temporaryFile2)
		finally
		{
			temporaryFile1.delete()
			temporaryFile2.delete()
		}
	}
	private def unsigned(b: Int): Int = ((b: Int) +256) % 256
	private def unsigned(b: Byte): Int = unsigned(b: Int)
	private def process(command: String) =
	{
		val ignore = echo // just for the compile dependency so that this test is rerun when TestedProcess.scala changes, not used otherwise

		val thisClasspath = List(getSource[Product], getSource[IO.type], getSource[SourceTag]).mkString(File.pathSeparator)
		"java -cp " + thisClasspath + " " + command
	}
	private def getSource[T : Manifest]: String =
		IO.classLocationFile[T].getAbsolutePath
}
private trait SourceTag