#!/usr/bin/ruby

# ---    MP3 Control    ---
# 
# Author: 	Magnus Engström
# Email:		magnus@gisab.se
# File:		mp3controld
#
# Description
# -----------
# An application which manages
# mp3 songs on the poor users
# computer.
# -------------------------

# --- External files ---
# Change directory to find all functions
#Dir::chdir("/usr/lib/mp3control")

load "extras/config_file"		# Handles the mp3controld.conf configuration file
load "extras/cmdline_parse"	# Provides the Commandline::parse which returns an hash of the commandline
load "extras/showHelp"			# Hmmm... guess what? This function shows the help message =)
load "extras/errorMsg"			# Outputs error messages to the admin
load "extras/playlist"			# Core playlist functionality

# --- MP3Control - the main class ---
class MP3Control
  # --- Core functions ---
  # initialize() reads the config files and daemonizes! 
  def initialize()
	 # Parse the commandline
	 $commandline = Commandline::parse()
	 
	 # Display help if the commandline sucks
	 if($commandline == -1)
		showHelp()
		Kernel::exit(-1)
	 end

	 # Make this class instance a background daemon
	 daemonize() if($commandline["--daemon"] != 'no' && $commandline["-D"] != 'no')

	 # Read the configuration file
	 configfile = ( $commandline["--configfile"] ? $commandline["--configfile"] : 'configuration/mp3controld.conf' ) # Use the --configfile if supplied, else use the default /etc/mp3controld/mp3controld.conf
	 $configFile = ConfigFile::parse(configfile) # Create an new config file object
	 errorMsg("Configuration file #{configfile} isn't readable or doesn't exist!", 137) if($configFile == -1)
	 
	 # Find the default playlist (or use the user supplied one from the commandline)
	 defaultPlaylist = $configFile.getParam("programConfig", "defaultPlaylist")
	 defaultPlaylist = $commandline["--playlist"] if($commandline["--playlist"])
	 if( $configFile.getParam(defaultPlaylist, 'listFile').type == String) # Make sure the listFile contains a value
		if(FileTest.readable_real?( $configFile.getParam(defaultPlaylist, 'listFile') )) # Make sure this file is readable
		  # Cool. Everything looks alright. Lets create a playlist!
		  errorMsg("Loading playlist '#{defaultPlaylist}' from #{$configFile.getParam(defaultPlaylist, 'listFile')}...") if($commandline['--verbose'] == 'on')
		  $current_playlist = Playlist::create_from_file($configFile.getParam(defaultPlaylist, 'listFile'))
		  $current_playlist_name = defaultPlaylist
		  
		  # Errorhandling
		  errorMsg("Playlist creation from #{$current_playlist.filename} failed.", 1) if($current_playlist == -1) # Quit and complain if it didn't work
		  errorMsg("Playlist #{defaultPlaylist} (#{$current_playlist.filename}) doesn't contain any entries.", 1) if($current_playlist.length() < 1)
		  errorMsg("Playlist '#{defaultPlaylist}' loaded successfully.") if($commandline["--verbose"] == 'on')

		  # Fix wrap/repeat and shuffle the playlist if the configfile says so
		  $current_playlist.wrap = true	if($configFile.getParam(defaultPlaylist, 'repeat') == 'true')
		  $current_playlist.shuffle()		if($configFile.getParam(defaultPlaylist, 'random') == 'true')
		  $current_playlist.goto(0)		# Rewind the playlist
		else
		  errorMsg("The default playlist doesn't appear to exist, or has the wrong permissions. That's not good.", 1)
		end
	 else # listFile returns other than string, that's baaaaad
		errorMsg("the listFile value for '#{defaultPlaylist}' doesn't appear to exist in your #{$configFile.filename}. That's not good.", 1)
	 end

	 # Check for the existence of our mpg123 instance
	 errorMsg("Trying to find the mp3 player...") if($commandline["--verbose"] == 'on')
	 @mpg123 = $configFile.getParam('programConfig', 'application') # Get the application name, path, and possible arguments
	 mpg123_application = @mpg123.scan(/^\S+/)
	 if(mpg123_application.type == Array)
		mpg123_application = mpg123_application[0] 
	 else
		errorMsg("Please check your ProgramConfig/application setting in the configuration file. It seems weird.", 1)
	 end

	 # Do some nice errorhandling
	 if( !FileTest::executable_real?(mpg123_application) )
		errorMsg("#{mpg123_application} doesn't appear to exist. Please do something about it (no, not \"touch #{mpg123_application}\"! Stupid!).", 1)
	 else
		errorMsg("Found #{mpg123_application}!") if($commandline["--verbose"] == 'on')
	 end

	 # Open an instance of mpg123, our high-performance mp3 player
	 @@mpg123 = IO::popen("#{@mpg123} -R -", 'r+')

	 # Start all plugins
	 load_plugins()

	 # Start the mp3 player
	 mpg123_control()

  end

  # mpg123_control() gets the input from the mpg123 process and handles it hopefully correctly :)
  def mpg123_control()

	 # Initialize class variables
	 @@stopped = false

	 # Start playing if the configfile says so
	 if( $configFile.getParam('programConfig', 'playOnStartup') == 'true' )
		MP3Control::play()
	 else
		puts("Dont want to play!")
	 end
	 
	 # The infinite 5 second loop =)
	 while(true)
		begin
		  input = @@mpg123.readline.chop()
		rescue EOFError
		  errorMsg("mpg123 error! Probably just a file that didn't exist (#{$current_playlist.song_info["filename"]}).")
		  @@mpg123 = IO::popen("#{@mpg123} -R -", 'r+') # Just start it again...
		  MP3Control::next_song() # Next song, so it doesn't die again...
		end

		# Song stopped
		MP3Control::next_song() if(input == '@P 0' && @@stopped != true) # Change to the next song if current song stops and the user didn't told it to
		@@stopped = false if(input == '@P 0' && @@stopped == true) # Reset the stop-flag if the user ordered the stop

		# Time left
		if(input[0,2] == '@F')
		  input =~ /^@F\s+\S+\s+\S+\s+(\S+)\s+(\S+)$/
		  @@time			= $1
		  @@timeleft	= $2
		end

	 end
  end

  # start() creates a new instance. Just like .new, but a nicer name. 
  def MP3Control::start()
	 MP3Control::new()
  end

 # daemonize() daemonizes this process. Cool =) 
  def daemonize()
	 if(child_pid = fork) # Parent code
		puts("PID #{child_pid}")
		Kernel::exit(0) # We dont want this parent process any more. Too bad.
	 end

	 # Child code. And child wants to be free from parent
	 Process.setsid()
  end

  # load_plugins() loads all plugins that can be found in the plugins directory
  def load_plugins()
	 Dir::entries('extras/plugins/').each { |plugin|
		# Try to load every plugin except all files that begins with a dot
		if(plugin[0].chr() != '.')
		  retval = 0
		  # Do some errorhandling
		  begin
			 load("extras/plugins/#{plugin}") # Load the files
			 errorMsg("Loaded plugin '#{plugin}'") if($commandline['--verbose'] == 'no')
		  rescue SyntaxError
			 errorMsg("Plugin '#{plugin}' has syntax errors.")
		  end

		  # Run the plugin in a separate thread
		  # Try to start the class with the same name as the plugin
		  eval("
		    Thread::new() {
				start_again = true
				while(start_again)
				  puts(\"Plugin starting...\")
				  begin
					 retval = #{plugin}::start()
				  rescue
					 error = $!
					 puts(error)
					 puts(error.backtrace)
					 puts(\"Error in plugin #{plugin}! Waiting for 5 seconds before attempting to start again...\")
					 sleep(5)
				  end
				  if(retval == -1) 
					 errorMsg(\"Plugin 'plugins/#{plugin}' failed to load...\")
					 start_again = false
				  end
				end
		    }
		  ") 

		end
	 }
  end

  # exit_mpg123() terminates the current mpg123 session
  def MP3Control::exit_mpg123()
	 #system("kill `pidof mpg123`") # Yes, I know this isn't a nice way to do it in, please fix this and send me a patch :)
  end

  # mpg123_command() sends a command to mpg123 
  def MP3Control::mpg123_command(command)
	 errorMsg("mpg123 command: '#{command}'") if($commandline['--verbose'] == 'on')
	 @@mpg123.write("#{command}\n")
	 @@mpg123.flush()
  end


  # --- play functions ---
  # play() plays the current index of the current playlist 
  def MP3Control::play()
	 @@stopped = false
	 mpg123_command("LOAD #{$current_playlist.song_info["filename"]}")
  end

  # stop() stops playing 
  def MP3Control::stop()
	 mpg123_command("PAUSE")
	 @@stopped = true # Set the stop-status to true
  end

  # pause() pauses playing 
  def MP3Control::pause()
	 @@stopped = false
	 mpg123_command("PAUSE")
  end

  # next_song() loads the next song. Yay... 
  def MP3Control::next_song()
	 retval = $current_playlist.next()
	 if(retval == -1)
		errorMsg("Error while changing to the next song.") # Tell him/her
	 else
		MP3Control::play() if(@@stopped == false)
	 end
  end

  # prev_song() loads the previous song. Yay... 
  def MP3Control::prev_song()
	 retval = $current_playlist.prev()
	 if(retval == -1)
		errorMsg("Error while changing to the previous song.") # Tell him/her
	 else
		MP3Control::play() if(@@stopped == false)
	 end
  end

  # forward(sec) jumps sec seconds forward
  def MP3Control::forward(sec)
	 mpg123_command("JUMP +#{sec*38}")
  end

  # backward(sec) jumps sec seconds backward
  def MP3Control::backward(sec)
	 mpg123_command("JUMP -#{sec*38}")
  end


  #  --- Misc functions ---
  # getTime() - Get the current song time information. getTime(true) for time left 
  def MP3Control::getTime(whichTime = 'elapsed')
	 case whichTime
	 when 'elapsed'
		parsed	= Time::at(@@time.to_i)
	 when 'left'
		parsed	= Time::at(@@timeleft.to_i)
	 when 'total'
		parsed	= Time::at( (@@time.to_f + @@timeleft.to_f).to_i )
	 end

	 hour	= (parsed.hour - 1).to_s
	 min	= parsed.min.to_s
	 sec	= parsed.sec.to_s

	 hour	= "0#{hour}"	if(hour.length == 1)
	 min	= "0#{min}"		if(min.length == 1)
	 sec	= "0#{sec}"		if(sec.length == 1)

	 hour = (hour == '00' ? '' : "#{hour}:")

	 # Return the now formatted time
	 "#{hour}#{min}:#{sec}"
  end

end

# Create an instance of the MP3Control class and start the application
MP3Control::start()