#!ruby

# --- Playlist class ---
#
# Author:	Magnus Engström
# Email:		magnus@gisab.se
# File:		playlist
#
# Description
# -----------
# The Playlist class handles everything a playlist should be able to manage.
# Shuffle it, unshuffle it, wrap it if desired, add new songs, find songs and
# so on. Cool huh? :)
# ----------------------

class Playlist
  # create_from_file() creates a playlist from a file and returns either a Playlist instance or -1 in case of error
  # This function should be used instead of the ::new, because this one
  # returns -1 on file read errors, which the ::new doesn't.
  def Playlist::create_from_file(filename)
	 # Check that the file is readable
	 if(FileTest::readable_real?(filename))
		new(filename) # Return the Playlist class instance
	 else
		-1 # Return -1 on error
	 end
  end

  # initialize reads the playlist from a file and returns the Playlist instance 
  def initialize(filename)

	 @filename	= filename		# Store the filename for later use
	 @playlist	= Array::new()	# This hash contains the whole playlist
	 @index		= 0				# Playlist's current position
	 @wrap		= false			# Don't repeat the list as default

	 # Parse these fields, separated with double pipes (||) (songname, artist, album, year, comment, tracknum, genre_id, genre)
	 File::foreach(filename) { |line| # Iterate through every line in the file
		foo = line.split(/\|\|/)
		@playlist << { "filename" => foo[0], "songname" => foo[1], "artist" => foo[2], "album" => foo[3], "year" => foo[4], "comment" => foo[5], "tracknum" => foo[6], "genre_id" => foo[7], "genre" => foo[8] } # Add a hash to the @playlist array with all values found in the playlist file
	 }
	 
  end

  def insert(song, placement = 0)
	 # Check song information
	 return -1 if(song.type != Hash)
	 song = { "filename" => song["filename"], "songname" => song["songname"], "artist" => song["artist"], "album" => song["album"], "year" => song["year"], "comment" => song["comment"], "tracknum" => song["tracknum"], "genre_id" => song["genre_id"], "genre" => song["genre"] }
	 
	 # Check minimum and maximum values
	 placement = 0 if(placement < 0)
	 placement = @playlist.length() if(placement > @playlist.length() )

	 # Retrieve the two parts of the split playlist
	 first		= @playlist[0...placement]
	 second		= @playlist[placement...@playlist.length()]
	 
	 # Put it together again
	 @playlist	= Array::new()
	 @playlist	= first
	 @playlist	<< song
	 @playlist.concat(second)

  end

  def remove(placement = 0)
	 # Check boundaries
	 placement = 0 if(placement < 0)
	 placement = @playlist.length()-1 if( placement >= @playlist.length() )

	 # Delete the item
	 @playlist.delete_at(placement)
  end

  def find(search_string, case_insensitive = false, fields = ["songname", "filename"])
	 case_insensitive = nil if(case_insensitive == false)

	 results	= Array::new()
	 regex	= Regexp::new(search_string, case_insensitive) # The regex that will be matched

	 # Iterate through the playlist to find one or more matching songs
	 @playlist.length().times { |index|
		# Iterate through the user supplied list of fields to be searched
		fields.each { |field|
		  # Make sure this is a hash, so we don't go and crash, or make someone's dog sick :)
		  if(@playlist[index].type == Hash)
			 results << index if( regex.match(@playlist[index][field]) && !(results.include?(index)) ) # If it matches, and if it doesn't already is in the results. We don't want duplicates :)
		  end
		}
	 }

	 results # Return the results

  end

  def shuffle()
	 # Iterate through the playlist
	 ( 0...@playlist.length() ).each { |i|
	  	j = rand @playlist.length() # Grab a random value between 0 and @playlist.length()

		# Maintain index
		if(@index == j)
		  @index = i 
		elsif(@index == i)
		  @index = j
		end

	  	@playlist[i], @playlist[j] = @playlist[j], @playlist[i]
	 }
  end

  def re_read()
	 # Maintain index
	 current_filename = @playlist[@index]["filename"]

	 # Create a new playlist array
	 @playlist	= Array::new()
	 @index		= 0
	 foo_index	= 0 # Just to keep the count while adding all songs to the @playlist

	 # Parse these fields, separated with double pipes (||) (songname, artist, album, year, comment, tracknum, genre_id, genre)
	 # Iterate through every line in the file
	 File::foreach(@filename) { |line|
		foo = line.split(/\|\|/) # Separate the fields with double pipes (||)
		@playlist << { "filename" => foo[0], "songname" => foo[1], "artist" => foo[2], "album" => foo[3], "year" => foo[4], "comment" => foo[5], "tracknum" => foo[6], "genre_id" => foo[7], "genre" => foo[8] } # Add a hash to the @playlist array with all values found in the playlist file

		# Maintain index
		@index = foo_index if(foo[0] == current_filename)
		foo_index += 1
	 }
	 
  end

  def next()
	 # Increase the counter and return -1 if the playlist went to far, and wrap isn't true
	 @index += 1
	 if( @index >= @playlist.length() )
		if(@wrap)
		  @index = 0
		else
		  @index -= 1
		  -1 # Return an error
		end
	 else
		@index
	 end
  end

  def prev()
	 # Decrease the counter and return -1 if the playlist went to far, and wrap isn't true
	 @index -= 1
	 if( @index < 0 )
		if(@wrap)
		  @index = @playlist.length() -1
		else
		  @index += 1
		  -1 # Return an error
		end
	 else
		@index
	 end
  end

  def song_info(index = @index)
	 @playlist[index]
  end

  def goto(index = 0)
	 if( index >= 0 && index < @playlist.length() )
		@index = index
	 else
		return -1
	 end
  end

  def length()
	 @playlist.length()
  end

  def each()
	 @playlist.each { |song| yield(song) }
  end

  attr_reader	:wrap, :index, :filename
  attr_writer	:wrap
end