/* sbt -- Simple Build Tool
 * Copyright 2009, 2010  Mark Harrah
 */
package sbt

	import java.io.File
	import complete.{DefaultParsers, EditDistance, Parser}
	import Types.const

sealed trait Command {
	def help: State => Help
	def parser: State => Parser[() => State]
	def tags: AttributeMap
	def tag[T](key: AttributeKey[T], value: T): Command
}
private[sbt] final class SimpleCommand(val name: String, private[sbt] val help0: Help, val parser: State => Parser[() => State], val tags: AttributeMap) extends Command {
	assert(Command validID name, "'" + name + "' is not a valid command name." )
	def tag[T](key: AttributeKey[T], value: T): SimpleCommand = new SimpleCommand(name, help0, parser, tags.put(key, value))
	def help = const(help0)
}
private[sbt] final class ArbitraryCommand(val parser: State => Parser[() => State], val help: State => Help, val tags: AttributeMap) extends Command
{
	def tag[T](key: AttributeKey[T], value: T): ArbitraryCommand = new ArbitraryCommand(parser, help, tags.put(key, value))
}

object Command
{
		import DefaultParsers._

	def command(name: String, briefHelp: String, detail: String)(f: State => State): Command  =  command(name, Help(name, (name, briefHelp), detail))(f)
	def command(name: String, help: Help = Help.empty)(f: State => State): Command  =  make(name, help)(state => success(() => f(state)))

	def make(name: String, briefHelp: (String, String), detail: String)(parser: State => Parser[() => State]): Command =
		make(name, Help(name, briefHelp, detail) )(parser)
	def make(name: String, help: Help = Help.empty)(parser: State => Parser[() => State]): Command  =  new SimpleCommand(name, help, parser, AttributeMap.empty)

	def apply[T](name: String, briefHelp: (String, String), detail: String)(parser: State => Parser[T])(effect: (State,T) => State): Command =
		apply(name, Help(name, briefHelp, detail) )(parser)(effect)
	def apply[T](name: String, help: Help = Help.empty)(parser: State => Parser[T])(effect: (State,T) => State): Command  =
		make(name, help)(applyEffect(parser)(effect) )

	def args(name: String, briefHelp: (String, String), detail: String, display: String)(f: (State, Seq[String]) => State): Command =
		args(name, display, Help(name, briefHelp, detail) )(f)
	
	def args(name: String, display: String, help: Help = Help.empty)(f: (State, Seq[String]) => State): Command =
		make(name, help)( state => spaceDelimited(display) map apply1(f, state) )

	def single(name: String, briefHelp: (String, String), detail: String)(f: (State, String) => State): Command =
		single(name, Help(name, briefHelp, detail) )(f)
	def single(name: String, help: Help = Help.empty)(f: (State, String) => State): Command =
		make(name, help)( state => token(trimmed(spacedAny(name)) map apply1(f, state)) )

	def custom(parser: State => Parser[() => State], help: Help = Help.empty): Command  =  customHelp(parser, const(help))
	def customHelp(parser: State => Parser[() => State], help: State => Help): Command  =  new ArbitraryCommand(parser, help, AttributeMap.empty)
	def arb[T](parser: State => Parser[T], help: Help = Help.empty)(effect: (State, T) => State): Command  =  custom(applyEffect(parser)(effect), help)

	def validID(name: String) = DefaultParsers.matches(OpOrID, name)

	def applyEffect[T](parser: State => Parser[T])(effect: (State, T) => State): State => Parser[() => State] =
		s => applyEffect(parser(s))(t => effect(s,t))
	def applyEffect[T](p: Parser[T])(f: T => State): Parser[() => State] =
		p map { t => () => f(t) }

	def combine(cmds: Seq[Command]): State => Parser[() => State] =
	{
		val (simple, arbs) = separateCommands(cmds)
		state => (simpleParser(simple)(state) /: arbs.map(_ parser state) ){ _ | _ }
	}
	private[this] def separateCommands(cmds: Seq[Command]): (Seq[SimpleCommand], Seq[ArbitraryCommand]) =
		Util.separate(cmds){ case s: SimpleCommand => Left(s); case a: ArbitraryCommand => Right(a) }
	private[this] def apply1[A,B,C](f: (A,B) => C, a: A): B => () => C =
		b => () => f(a,b)

	def simpleParser(cmds: Seq[SimpleCommand]): State => Parser[() => State] =
		simpleParser(cmds.map(sc => (sc.name, argParser(sc) )).toMap )
	private[this] def argParser(sc: SimpleCommand): State => Parser[() => State] =
	{
		def usageError = s"${sc.name} usage:" + Help.message(sc.help0, None)
		s => (Parser.softFailure(usageError, definitive = true): Parser[() => State]) | sc.parser(s)
	}

	def simpleParser(commandMap: Map[String, State => Parser[() => State]]): State => Parser[() => State] =
		(state: State) => token(OpOrID examples commandMap.keys.toSet) flatMap { id =>
			(commandMap get id) match {
				case None => failure(invalidValue("command", commandMap.keys)(id))
				case Some(c) => c(state)
			}
		}
		
	def process(command: String, state: State): State =
	{
		val parser = combine(state.definedCommands)
		parse(command, parser(state)) match
		{
			case Right(s) => s() // apply command.  command side effects happen here
			case Left(errMsg) =>
				state.log.error(errMsg)
				state.fail				
		}
	}
	def invalidValue(label: String, allowed: Iterable[String])(value: String): String =
		"Not a valid " + label + ": " + value + similar(value, allowed)
	def similar(value: String, allowed: Iterable[String]): String =
	{
		val suggested = if(value.length > 2) suggestions(value, allowed.toSeq) else Nil
		if(suggested.isEmpty) "" else suggested.mkString(" (similar: ", ", ", ")")
	}
	def suggestions(a: String, bs: Seq[String], maxDistance: Int = 3, maxSuggestions: Int = 3): Seq[String] =
		bs.map { b => (b, distance(a, b) ) } filter (_._2 <= maxDistance) sortBy(_._2) take(maxSuggestions) map(_._1)
	def distance(a: String, b: String): Int =
		EditDistance.levenshtein(a, b, insertCost = 1, deleteCost = 1, subCost = 2, transposeCost = 1, matchCost = -1, caseCost = 1, true)

	def spacedAny(name: String): Parser[String] = spacedC(name, any)
	def spacedC(name: String, c: Parser[Char]): Parser[String] =
		( (c & opOrIDSpaced(name)) ~ c.+) map { case (f, rem) => (f +: rem).mkString }
}

trait Help
{
	def detail: Map[String, String]
	def brief: Seq[(String, String)]
	def more: Set[String]
	def ++(o: Help): Help
}
private final class Help0(val brief: Seq[(String,String)], val detail: Map[String,String], val more: Set[String]) extends Help
{
	def ++(h: Help): Help = new Help0(Help0.this.brief ++ h.brief, Help0.this.detail ++ h.detail, more ++ h.more)
}
object Help
{
	val empty: Help = briefDetail(Nil)

	def apply(name: String, briefHelp: (String, String), detail: String): Help  =  apply(briefHelp, Map( (name, detail) ) )

	def apply(briefHelp: (String, String), detailedHelp: Map[String, String] = Map.empty ): Help =
		apply(briefHelp :: Nil, detailedHelp)

	def apply(briefHelp: Seq[(String,String)], detailedHelp: Map[String,String]): Help =
		apply(briefHelp, detailedHelp, Set.empty[String])
	def apply(briefHelp: Seq[(String,String)], detailedHelp: Map[String,String], more: Set[String]): Help =
		new Help0(briefHelp, detailedHelp, more)

	def more(name: String, detailedHelp: String): Help = apply(Nil, Map(name -> detailedHelp), Set(name))
	def briefDetail(help: Seq[(String, String)]): Help = apply(help, help.toMap)
	def briefOnly(help: Seq[(String, String)]): Help = apply(help, Map.empty[String,String])
	def detailOnly(help: Seq[(String, String)]): Help = apply(Nil, help.toMap)

		import CommandUtil._

	def message(h: Help, arg: Option[String]): String =
		arg match {
			case Some(x) => detail(x, h.detail)
			case None =>
				val brief = aligned("  ", "   ", h.brief).mkString("\n", "\n", "\n")
				val more = h.more.toSeq.sorted
				if(more.isEmpty)
					brief
				else
					brief + "\n" + moreMessage(more)
		}
	def moreMessage(more: Seq[String]): String =
		more.mkString("More command help available using 'help <command>' for:\n  ", ", ", "\n")
}
trait CommandDefinitions extends (State => State)
{
	def commands: Seq[Command] = ReflectUtilities.allVals[Command](this).values.toSeq
	def apply(s: State): State = s ++ commands
}