/* sbt -- Simple Build Tool
 * Copyright 2008, 2009, 2010  Mark Harrah
 */
package sbt

import Path._
import IO.{pathSplit, wrapNull}
import java.io.File
import java.net.URL
import scala.collection.{generic, immutable, mutable}

final class RichFile(val asFile: File)
{
	def / (component: String): File = if(component == ".") asFile else new File(asFile, component)
	/** True if and only if the wrapped file exists.*/
	def exists = asFile.exists
	/** True if and only if the wrapped file is a directory.*/
	def isDirectory = asFile.isDirectory
	/** The last modified time of the wrapped file.*/
	def lastModified = asFile.lastModified
	/* True if and only if the wrapped file `asFile` exists and the file 'other'
	* does not exist or was modified before the `asFile`.*/
	def newerThan(other: File): Boolean = Path.newerThan(asFile, other)
	/* True if and only if the wrapped file `asFile` does not exist or the file `other`
	* exists and was modified after `asFile`.*/
	def olderThan(other: File): Boolean = Path.newerThan(other, asFile)
	/** The wrapped file converted to a <code>URL</code>.*/
	def asURL = asFile.toURI.toURL
	def absolutePath: String = asFile.getAbsolutePath

	/** The last component of this path.*/
	def name = asFile.getName
	/** The extension part of the name of this path.  This is the part of the name after the last period, or the empty string if there is no period.*/
	def ext = baseAndExt._2
	/** The base of the name of this path.  This is the part of the name before the last period, or the full name if there is no period.*/
	def base = baseAndExt._1
	def baseAndExt: (String, String) =
	{
		val nme = name
		val dot = nme.lastIndexOf('.')
		if(dot < 0) (nme, "") else (nme.substring(0, dot), nme.substring(dot+1))
	}

	def relativize(sub: File): Option[File] = Path.relativizeFile(asFile, sub)
	def relativeTo(base: File): Option[File] = Path.relativizeFile(base, asFile)

	def hash: Array[Byte] = Hash(asFile)
	def hashString: String = Hash.toHex(hash)
	def hashStringHalf: String = Hash.halve(hashString)
}
	import java.io.File
	import File.pathSeparator
trait PathLow
{
	implicit def singleFileFinder(file: File): PathFinder = PathFinder(file)
}
trait PathExtra extends Alternatives with Mapper with PathLow
{
	implicit def richFile(file: File): RichFile = new RichFile(file)
	implicit def filesToFinder(cc: Traversable[File]): PathFinder = PathFinder.strict(cc)
}
object Path extends PathExtra
{
	def apply(f: File): RichFile = new RichFile(f)
	def apply(f: String): RichFile = new RichFile(new File(f))
	def fileProperty(name: String): File = new File(System.getProperty(name))
	def userHome: File = fileProperty("user.home")

	def absolute(file: File): File = new File(file.toURI.normalize).getAbsoluteFile
	def makeString(paths: Seq[File]): String = makeString(paths, pathSeparator)
	def makeString(paths: Seq[File], sep: String): String = paths.map(_.getAbsolutePath).mkString(sep)
	def newerThan(a: File, b: File): Boolean = a.exists && (!b.exists || a.lastModified > b.lastModified)

	/** The separator character of the platform.*/
	val sep = java.io.File.separatorChar

	def relativizeFile(baseFile: File, file: File): Option[File] = relativize(baseFile, file).map { path => new File(path) }
	private[sbt] def relativize(baseFile: File, file: File): Option[String] =
	{
		val pathString = file.getAbsolutePath
		baseFileString(baseFile) flatMap
		{
			baseString =>
			{
				if(pathString.startsWith(baseString))
					Some(pathString.substring(baseString.length))
				else
					None
			}
		}
	}
	private def baseFileString(baseFile: File): Option[String] =
		if(baseFile.isDirectory)
		{
			val cp = baseFile.getAbsolutePath
			assert(cp.length > 0)
			if(cp.charAt(cp.length - 1) == File.separatorChar)
				Some(cp)
			else
				Some(cp + File.separatorChar)
		}
		else
			None

	def toURLs(files: Seq[File]): Array[URL] = files.map(_.toURI.toURL).toArray
}
object PathFinder
{
	/** A <code>PathFinder</code> that always produces the empty set of <code>Path</code>s.*/
	val empty = new PathFinder { private[sbt] def addTo(fileSet: mutable.Set[File]) {} }
	def strict(files: Traversable[File]): PathFinder = apply(files)
	def apply(files: => Traversable[File]): PathFinder = new PathFinder {
		private[sbt] def addTo(fileSet: mutable.Set[File]) = fileSet ++= files
	}
	def apply(file: File): PathFinder = new SingleFile(file)
}

/** A path finder constructs a set of paths.  The set is evaluated by a call to the <code>get</code>
* method.  The set will be different for different calls to <code>get</code> if the underlying filesystem
* has changed.*/
sealed abstract class PathFinder
{
	/** The union of the paths found by this <code>PathFinder</code> with the paths found by 'paths'.*/
	def +++(paths: PathFinder): PathFinder = new Paths(this, paths)
	/** Excludes all paths from <code>excludePaths</code> from the paths selected by this <code>PathFinder</code>.*/
	def ---(excludePaths: PathFinder): PathFinder = new ExcludeFiles(this, excludePaths)
	/** Constructs a new finder that selects all paths with a name that matches <code>filter</code> and are
	* descendants of paths selected by this finder.*/
	def **(filter: FileFilter): PathFinder = new DescendantOrSelfPathFinder(this, filter)
	def *** : PathFinder = **(AllPassFilter)
	/** Constructs a new finder that selects all paths with a name that matches <code>filter</code> and are
	* immediate children of paths selected by this finder.*/
	def *(filter: FileFilter): PathFinder = new ChildPathFinder(this, filter)
	/** Constructs a new finder that selects all paths with name <code>literal</code> that are immediate children
	* of paths selected by this finder.*/
	def / (literal: String): PathFinder = new ChildPathFinder(this, new ExactFilter(literal))
	/** Constructs a new finder that selects all paths with name <code>literal</code> that are immediate children
	* of paths selected by this finder.*/
	final def \ (literal: String): PathFinder = this / literal

	def x_![T](mapper: File => Option[T]): Traversable[(File,T)] = x(mapper, false)

	/** Applies `mapper` to each path selected by this PathFinder and returns the path paired with the non-empty result.
	* If the result is empty (None) and `errorIfNone` is true, an exception is thrown.
	* If `errorIfNone` is false, the path is dropped from the returned Traversable.*/
	def pair[T](mapper: File => Option[T], errorIfNone: Boolean = true): Seq[(File,T)] =
		x(mapper, errorIfNone)

	/** Applies `mapper` to each path selected by this PathFinder and returns the path paired with the non-empty result.
	* If the result is empty (None) and `errorIfNone` is true, an exception is thrown.
	* If `errorIfNone` is false, the path is dropped from the returned Traversable.*/
	def x[T](mapper: File => Option[T], errorIfNone: Boolean = true): Seq[(File,T)] =
	{
		val apply = if(errorIfNone) mapper | fail else mapper
		for(file <- get; mapped <- apply(file)) yield (file, mapped)
	}

	/** Selects all descendant paths with a name that matches <code>include</code> and do not have an intermediate
	* path with a name that matches <code>intermediateExclude</code>.  Typical usage is:
	*
	* <code>descendantsExcept("*.jar", ".svn")</code>*/
	def descendantsExcept(include: FileFilter, intermediateExclude: FileFilter): PathFinder =
		(this ** include) --- (this ** intermediateExclude ** include)
	@deprecated("Use `descendantsExcept` instead.", "0.12.0")
	def descendentsExcept(include: FileFilter, intermediateExclude: FileFilter): PathFinder =
		descendantsExcept(include, intermediateExclude)

	/** Evaluates this finder and converts the results to a `Seq` of distinct `File`s.  The files returned by this method will reflect the underlying filesystem at the
	* time of calling.  If the filesystem changes, two calls to this method might be different.*/
	final def get: Seq[File] =
	{
			import collection.JavaConversions._
		val pathSet: mutable.Set[File] = new java.util.LinkedHashSet[File]
		addTo(pathSet)
		pathSet.toSeq
	}
	@deprecated("Use `get`"/*, "0.9.7"*/) def getFiles: Seq[File] = get
	/** Only keeps paths for which `f` returns true.  It is non-strict, so it is not evaluated until the returned finder is evaluated.*/
	final def filter(f: File => Boolean): PathFinder = PathFinder(get filter f)
	/* Non-strict flatMap: no evaluation occurs until the returned finder is evaluated.*/
	final def flatMap(f: File => PathFinder): PathFinder = PathFinder(get.flatMap(p => f(p).get))
	/** Evaluates this finder and converts the results to an `Array` of `URL`s..*/
	final def getURLs: Array[URL] = get.toArray.map(_.toURI.toURL)
	/** Evaluates this finder and converts the results to a distinct sequence of absolute path strings.*/
	final def getPaths: Seq[String] = get.map(_.absolutePath)
	private[sbt] def addTo(fileSet: mutable.Set[File])

	/** Create a PathFinder from this one where each path has a unique name.
	* A single path is arbitrarily selected from the set of paths with the same name.*/
	def distinct: PathFinder = PathFinder { get.map(p => (p.asFile.getName, p)).toMap.values }

	/** Constructs a string by evaluating this finder, converting the resulting Paths to absolute path strings, and joining them with the platform path separator.*/
	final def absString = Path.makeString(get)
	/** Constructs a debugging string for this finder by evaluating it and separating paths by newlines.*/
	override def toString = get.mkString("\n   ", "\n   ","")
}
private class SingleFile(asFile: File) extends PathFinder
{
	private[sbt] def addTo(fileSet: mutable.Set[File]): Unit = if(asFile.exists) fileSet += asFile
}
private abstract class FilterFiles extends PathFinder with FileFilter
{
	def parent: PathFinder
	def filter: FileFilter
	final def accept(file: File) = filter.accept(file)

	protected def handleFile(file: File, fileSet: mutable.Set[File]): Unit =
		for(matchedFile <- wrapNull(file.listFiles(this)))
			fileSet += new File(file, matchedFile.getName)
}
private class DescendantOrSelfPathFinder(val parent: PathFinder, val filter: FileFilter) extends FilterFiles
{
	private[sbt] def addTo(fileSet: mutable.Set[File])
	{
		for(file <- parent.get)
		{
			if(accept(file))
				fileSet += file
			handleFileDescendant(file, fileSet)
		}
	}
	private def handleFileDescendant(file: File, fileSet: mutable.Set[File])
	{
		handleFile(file, fileSet)
		for(childDirectory <- wrapNull(file listFiles DirectoryFilter))
			handleFileDescendant(new File(file, childDirectory.getName), fileSet)
	}
}
private class ChildPathFinder(val parent: PathFinder, val filter: FileFilter) extends FilterFiles
{
	private[sbt] def addTo(fileSet: mutable.Set[File]): Unit =
		for(file <- parent.get)
			handleFile(file, fileSet)
}
private class Paths(a: PathFinder, b: PathFinder) extends PathFinder
{
	private[sbt] def addTo(fileSet: mutable.Set[File])
	{
		a.addTo(fileSet)
		b.addTo(fileSet)
	}
}
private class ExcludeFiles(include: PathFinder, exclude: PathFinder) extends PathFinder
{
	private[sbt] def addTo(pathSet: mutable.Set[File])
	{
		val includeSet = new mutable.LinkedHashSet[File]
		include.addTo(includeSet)

		val excludeSet = new mutable.HashSet[File]
		exclude.addTo(excludeSet)

		includeSet --= excludeSet
		pathSet ++= includeSet
	}
}
