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

import java.io.File

final class ParseException(msg: String) extends RuntimeException(msg)

/** Parses a load command. The implementation is a quick hack.
It is not robust and errors are not helpful.*/
object Parse
{
	def helpBrief(name: String, label: String): (String, String) = (name + " <options>", "Loads " + label + " according to the specified options.")
	def helpDetail(name: String, label: String, multiple: Boolean) =
"Loads " + label + """ by one of the following methods:
 1) binary: loads a class from an existing classpath
 2) source: compiles provided sources and loads a specific class
 3) project: builds from source using default settings

The command has the following syntax:

  load ::= """ + name + """ ('-help' | binary | source | project)

  binary ::= classpath module? name
  source ::= classpath? sources out? module? (detect | name)
  project ::= base? name?

  base ::= '-project' path
  sources ::=  '-src' paths
  out ::= '-d' dir
  detect ::= '-auto' ('sub' | 'annot')
  name ::= '-name' nameString
  module ::= '-module' ('true'|'false')
  classpath ::= '-cp' paths
  path ::= pathChar+
  paths ::= path (pathSep path)*
""" +
( if(multiple) "\nTo specify multiple names, separate them by commas." else "")

	import File.{pathSeparatorChar => sep}

	def error(msg: String) = throw new ParseException(msg)
	def apply(commandString: String)(implicit base: File): LoadCommand =
	{
		val args = arguments(commandString)
		val srcs = sourcepath(args)
		val nme = name(args)

		lazy val cp = classpath(args)
		lazy val mod = module(args)
		lazy val proj = project(args).getOrElse(base)

		if(!srcs.isEmpty)
			SourceLoad(cp, srcs, output(args), mod, auto(args), nme)
		else if(!cp.isEmpty)
			BinaryLoad(cp, mod.getOrElse(false), nme)
		else
			ProjectLoad(proj, auto(args), nme)
	}
	
	def arguments(in: String) = in.split("""\s+""").toSeq
	
	def compile(commandString: String)(implicit base: File): CompileCommand =
	{
		val args = arguments(commandString)
		CompileCommand(classpath(args), sourcepath(args), output(args), Nil)
	}
	def discover(commandString: String): DiscoverCommand =
	{
		val args = arguments(commandString)
		val subs = names("sub", args)
		val annots = names("annot", args)
		DiscoverCommand(module(args), new inc.Discovery(subs, annots))
	}
	
	def auto(args: Seq[String]): Auto.Value =
		getArg(args, "auto") match {
			case None => Auto.Explicit
			case Some("sub") => Auto.Subclass
			case Some("annot") => Auto.Annotation
			case Some(x) => error("Illegal auto argument '" + x + "'")
		}
	
	def module(args: Seq[String]): Option[Boolean] =
		getArg(args, "module") map {
			case "false" => false
			case "true" => true
			case x => error("Expected boolean, got '" + x + "'")
		}
		
	def names(label: String, args: Seq[String]): Set[String] =
		getArg(args, label) match { case Some(ns) => ns.split(",").toSet; case None => Set.empty }
		
	def name(args: Seq[String]): String =
		getArg(args, "name") getOrElse("")
	
	def output(args: Seq[String])(implicit base: File): Option[File] =
		getArg(args, "d") map file(base)
		
	def project(args: Seq[String])(implicit base: File): Option[File] =
		getArg(args, "project") map file(base)
	
	def pathArg(args: Seq[String], name: String)(implicit base: File): Seq[File] =
		getArg(args, name).toSeq flatMap paths
	
	def classpath(args: Seq[String])(implicit base: File): Seq[File] = pathArg(args, "cp")
	def sourcepath(args: Seq[String])(implicit base: File): Seq[File] = pathArg(args, "src")
	
	def getArg(args: Seq[String], name: String): Option[String] =
	{
		val opt = "-" + name
		val found = args.dropWhile(_ != opt)
		
		if(found.isEmpty)
			None
		else
			found.drop(1).headOption match
			{
				case x @ Some(arg) if !arg.startsWith("-") => x
				case _ => error("No argument provided for -" + name)
			}
	}

	def paths(implicit base: File): String => Seq[File] =
		_ split sep flatMap files(base)
		
	def files(base: File)(path: String): Seq[File] = readFinder(Path.fromFile(base), path).getFiles.toSeq
		
	def file(base: File) = (path: String) => Path.fromString(base, path).asFile
	
	def readFinder(base: File, s: String): PathFinder =
	{
		val f = new File(s)
		asFinder( if(f.isAbsolute) f else new File(base, s) )
	}
	def asFinder(f: File): PathFinder =
	{
		val parent = f.getParentFile
		if(parent eq null)
			Path.fromFile(f)
		else
		{
			val finder = asFinder(parent)
			val sub = f.getName
			if(sub == "**") (finder ***) else if(sub contains "*") finder * GlobFilter(sub) else finder / sub
		}
	}
}