#!/usr/bin/python

####
#### This is GPL'ed software
####

from sys import *
from sched import *
from time import *
from string import *
from os import environ

user_start_argument = 0

try:
	envport = environ['MIDIPLAYPORT']
	outport = open(envport,'w')
except:
	outport =open('/dev/ttyS0','w')

only_channel = -1 ### default, play all channels !

if len(argv) > 2:
	if '-t' in argv:
		time_argument = argv.index('-t') + 1
		time_argument = argv[time_argument]
		time_argument = time_argument.split(':')
		time_argument[0] = int(time_argument[0])*60
		time_argument[1] = int(time_argument[1])
		user_start_argument = time_argument[0]+time_argument[1]
		running_status = 1
		status_byte = 0x90
	if '-p' in argv:
		port_argument = argv.index('-p') + 1
		port_argument = argv[port_argument]
		outport = open(port_argument,'w')
	if '-c' in argv:
		only_channel = argv.index('-c') + 1
		only_channel = argv[only_channel]
		only_channel = int(only_channel)-1
	
midi_file = open(argv[-1],'r') ### file is last argument
midi_file.seek(-1,2)
song_end = midi_file.tell()
midi_file.seek(0)
tempo = 500000
bendstring = ''
running_status = 0

def rel_time():
	global start_time, user_start_argument
	return (time()-start_time) + user_start_argument

s = scheduler(rel_time,sleep)

def portwrite(string):
	global outport
	outport.write("%s" % string)
	outport.flush()

def all_notes_off():
	global outport
	for channel in range(16):
		outport.write("%c%c%c" % (0xB0+channel, 123, 0))
		outport.flush()

def read_var_length():
	output = 0
	inbyte = ord(midi_file.read(1))
	output = inbyte & 0x7f
	while (inbyte & 0x80) == 0x80:
		inbyte = ord(midi_file.read(1))
		output = (output << 7 ) + (inbyte & 0x7f)
	return output

def header_read():
	global midi_file,type,tracks,timebase
	if midi_file.read(4) != 'MThd':
		print "Not a midi file, sorry"
		exit()
	midi_file.read(4) ###pass the '00 00 00 06'
	midi_file.read(1)
	type = ord(midi_file.read(1))
	midi_file.read(1)
	tracks = ord(midi_file.read(1))
	if type == 0 and tracks != 1:
		print "Midi files of type 0 should only have one track."
		exit()
	timebase = (ord(midi_file.read(1)) << 8) + ord(midi_file.read(1))

def track_read():
	global midi_file,song_end,miditime
	if midi_file.read(4) != 'MTrk':
		print "No midi track header found at 0x%x" % (midi_file.tell()-4)
		exit()
	track_length = (ord(midi_file.read(1)) << 24) + (ord(midi_file.read(1)) << 16) + (ord(midi_file.read(1)) << 8) + ord(midi_file.read(1))
	miditime = 0 #### zero our track time
	song_position = midi_file.tell() #### where are we in the file?
	if track_length == 0:
		track_end = song_end
	else:
		track_end = song_position + track_length
	while song_position < track_end :
		parse()
		song_position = midi_file.tell()

def parse():
	global midi_file,miditime,tempo,timebase,running_status,status_byte,status_byte_size,bendstring
	delta = read_var_length()
	miditime = miditime + ((delta/(timebase+0.0))*(tempo/1000000.0))
	##### check to see if next byte is a status byte:
	byte = midi_file.read(1)
	if ord(byte) == 0xFF : ##### meta events
		meta_byte = ord(midi_file.read(1))
		if meta_byte == 0x51:
			midi_file.read(1) ### pass the superfluous '03' length, we know what to do!
			tempo = (ord(midi_file.read(1)) << 16) + (ord(midi_file.read(1)) << 8) + ord(midi_file.read(1))
		elif meta_byte == 0x2f:
			midi_file.read(1)
		else:
			### we don't care what the meta_event is, buddy!!!!
			text_length = read_var_length()
			midi_file.read(text_length) ##### skip it!
	elif (ord(byte) == 0xF0) or (ord(byte) == 0xF7): #### sysex events
		sysex_length = read_var_length()
		sysex_message = [midi_file.read(sysex_length)]
		s.enterabs(miditime, 1, portwrite, (sysex_message))
	elif (0xC0 <= ord(byte) <= 0xD0): ##### program change, aftertouch
		running_status = 1
		status_byte = ord(byte)
		status_byte_size = 1
		outstring = ["%c%c" % (byte, midi_file.read(1))]
		s.enterabs(miditime, 1, portwrite, (outstring))
	elif (ord(byte) & 0x80) == 0x80: #### everything else
		running_status = 1
		status_byte = ord(byte)
		status_byte_size = 2
		outstring = ["%c%s" % (byte, midi_file.read(2))]
		if (only_channel == -1) or (status_byte & 0x0F == only_channel):
			if (status_byte & 0xF0) == 0xE0:
				s.enterabs(miditime, 1, portwrite, (outstring))
			else:
				s.enterabs(miditime, 2, portwrite,(outstring))
	elif running_status:
		midi_file.seek(-1,1)
		outstring = ["%c%s" % (status_byte,midi_file.read(status_byte_size))]
		s.enterabs(miditime, 1, portwrite, (outstring))

try:
	header_read()
	for x in range(tracks):
		track_read() ##### load the sequencer queue
	if type == 1: 	       ##### this is only necessary
		print "wait a sec...sorting the type 1 midi_tracks into sequential order....."
		s.queue.sort() ##### if the file has separate midi tracks
		print "ok...playing....."
	if type == 2:
		print "sorry, type 2 midi files are not playable from this sequencer."
		exit()
	if user_start_argument > 0:
		queue_index = 0
		try:
			while s.queue[queue_index][0] < user_start_argument:
				queue_index += 1
		except:
			print "time argument too big for this file."
			print "fool around with a smaller value..."
			exit()
		s.queue.__delslice__(0,queue_index)
	start_time = time() #### play reference point starts now
	s.run() #### run the sequencer queue
	midi_file.close()
	outport.close()
except KeyboardInterrupt:
	all_notes_off()
	midi_file.close()
	outport.close()