#!/usr/pkg/bin/python
"""coerce brainwaves to a particular beat frequency

   the theory is that by playing, say, 500 Hz into the left ear and 505 Hz
   into the right, your brain picks up on the 'beat frequency' of 5 Hz and
   will attempt to 'tune' itself to that frequency. You can thus supposedly
   control your level of consciousness, producing certain chemicals on
   demand, even assist an out-of-body experience. We shall see.
   The levels, IIRC:
    Beta: 14 Hz+
    Alpha: 8 - 14 Hz
    Delta: 4 - 8 Hz
    Theta: 0 - 4 Hz"""

Copyright = """
    brainwave - coerce brainwaves to a particular beat frequency
    Copyright (C) 2004  John Comeau <jc@jcomeau.com>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
    """
errormessage = "Not all needed libraries found, upgrade or check path"
try:
 True # not defined in older Python releases
except:
 True, False = 1, 0
try:
 import sys, os, types, re, pwd
 sys.path.append(os.sep.join([pwd.getpwuid(os.geteuid())[5], 'lib', 'python']))
 from com.jcomeau import gpl, jclicense
except:
 try:
  sys.stderr.write("%s\n" % errormessage)
 except:
  print errormessage
 raise

# get name this program was called as
self = sys.argv[0].split(os.sep)[-1]
# now get name we gave it when we wrote it
originalself = Copyright.split()[0]

# globals and routines that should be in every program
# (yes, you could import them, but there are problems in that approach too)

def DebugPrint(*whatever):
 pass # defined instead by pytest module, use that for debugging

# other globals, specific to this program

import time
from com.jcomeau import arcane
from com.jcomeau.midi import midi, pymidi

def brainwave(*args):
 "generate slightly different notes in each ear"
 defaults = ['C5', 12]
 try:
  while type(args[0]) is types.ListType or type(args[0]) is types.TupleType:
   args = args[0]
 except:
  args = ()
 if len(args) < 2:
  sys.stderr.write("Usage: %s NOTE BEAT_FREQUENCY [DURATION(ms)]\n" % self)
  sys.stderr.write("Example: %s C#5 5 500 # plays for 1/2 sec\n" % self)
  sys.stderr.write("         %s C#5 5 # plays until control-C\n" % self)
  sys.exit(0)
 if DebugPrint():
  midi.DebugPrint = DebugPrint # cascade debugging to other modules
 notes = arcane.ReverseDict(midi.NoteMapping('all', 'midi'))
 try:
  note = notes[args[0]]
 except:
  sys.stderr.write("Could not map note %s to MIDI note\n" % args[0])
  sys.stderr.write("Using %s instead\n" % defaults[0])
  note = notes[defaults[0]]
 try:
  beat_frequency = float(args[1])
 except:
  sys.stderr.write("Could not understand beat frequency of %s\n" % args[1])
  sys.stderr.write("Using frequency %f instead\n" % float(defaults[1]))
  sys.stderr.write("If this is undesirable, Control-C to stop\n")
  beat_frequency = float(defaults[1])
 try:
  duration = float(args[2])
 except:
  sys.stderr.write("No duration or invalid duration specified\n")
  sys.stderr.write("Playing note forever until key is hit\n")
  duration = 0
 midihandle = pymidi.open("/dev/midi", "wb")
 # piano (default) sound decays too rapidly, try something else...
 midi.SetChannelProgram(midihandle, 0, 'Flute')
 midi.SetChannelProgram(midihandle, 1, 'Flute')
 # one channel for each ear; needless to say, headphones are needed for this
 midi.SetChannelPan(midihandle, 0, 0) # set channel 0 pan to hard left
 midi.SetChannelPan(midihandle, 1, 127) # set channel 1 pan to hard right
 # now alter frequency to right ear, within accuracy of the routine
 midi.SetChannelPitchFrequency(midihandle, 1, note, beat_frequency)
 # time to face the music
 pymidi.write(midihandle, (0x90, note, 64)) # tone to left ear
 if DebugPrint("Delaying before starting tone to right ear..."):
  time.sleep(5)
 if DebugPrint("Shutting down tone to left ear before starting right..."):
  pymidi.write(midihandle, (0x90, note, 0))
 pymidi.write(midihandle, (0x91, note, 64)) # tone to right ear
 if duration != 0:
  time.sleep(duration / 1000)
  pymidi.write(midihandle, (0x90, note, 0)) # end tone to left ear
  pymidi.write(midihandle, (0x91, note, 0)) # end tone to right ear
  pymidi.close(midihandle)
 else:
  arcane.pause("Hit <ENTER> to stop...")
  pymidi.write(midihandle, (0x90, note, 0)) # end tone to left ear
  pymidi.write(midihandle, (0x91, note, 0)) # end tone to right ear
  pymidi.close(midihandle)

if __name__ == '__main__':
 # if this program was imported by another, the above test will fail,
 # and this following code won't be used...
 brainwave(sys.argv[1:])