#!/usr/bin/python3

import sys, os, subprocess, mido

def getarg(pos, default):
	if len(sys.argv) > pos:
		return sys.argv[pos]
	return default

class Encoder:
	def __init__(self, fp=None, fp_log=sys.stderr):
		self.fp = fp if fp == None or fp.mode == "wb" else os.fdopen(fp.fileno(), 'wb')
		self.fp_log = fp_log

		self.sampling = 16000
		self.signed = True
		self.verbose = False
		self.bits = 16
		self.msbfirst = True

	def write(self, amplitude):
		if self.fp == None:
			aplay = subprocess.Popen([
				"aplay",
				"-r",
				str(self.sampling),
				"-f",
				("S" if self.signed else "U") + str(self.bits) + "_" + ("LE" if self.msbfirst else "BE")
			], stdin=subprocess.PIPE, stderr=self.fp_log)
			self.fp = aplay.stdin

		smax = 2**(self.bits-self.signed)-1
		if self.signed:
			v = int(amplitude*smax)
			w = v
			s = v < 0
			v = abs(v)
			if s:
				v = smax-v
			v |= s << (self.bits-1)
		else:
			v = int((amplitude*smax+smax)/2)
			w = v
		
		if self.msbfirst:
			i = 0
			while i < self.bits:
				if self.fp.write(bytes([(v>>i)&255])) > 1:
					self.fp_log.write(str(v))
				if self.verbose:
					self.fp_log.write(bin((v>>i)&255)[2:].zfill(8))
				i += 8
		else:
			i = self.bits
			while i > 0:
				i -= 8
				self.fp.write(bytes([(v>>i)&255]))
				if self.verbose:
					self.fp_log.write(bin((v>>i)&255)[2:].zfill(8))
		
		if self.verbose:
			self.fp_log.write("  "+"0"*(self.bits-len(bin(v))+2)+bin(v)[2:]+"  "+str(v)+"  "+str(w)+"\n")

class Event:
	def __init__(self, type):
		self.type = type

class Wait(Event):
	def __init__(self, value):
		Event.__init__(self, Wait)
		self.value = value
	
	def dict(self):
		return {
			"type": "wait",
			"number": self.value,
		}

class End(Event):
	def __init__(self):
		Event.__init__(self, End)
	
	def dict(self):
		return {
			"type": "end"
		}

class Note(Event):
	def __init__(self, number, velocity, channel=0, track=0):
		Event.__init__(self, Note)
		self.number = number
		self.velocity = velocity
		self.channel = channel
		self.track = track
	
	def dict(self):
		return {
			"type": "note",
			"number": self.number,
			"velocity": self.velocity,
			"channel": self.channel
		}

def midi_events():
	if len(sys.argv) < 2:
		raise ValueError("Il faut donner le nom du fichier: python3 "+sys.argv[0]+" fichier.mid")
	return read_midi(sys.argv[1], float(getarg(2, 80)))

_midi = None
_midi_active = {}
_midi_wait = 0
_midi_tt = 0
_midi_loop = True
def midi2():
	global _midi, _midi_active, _midi_wait, _midi_tt, _midi_loop
	if _midi == None:
		_midi = midi_events()

	if _midi_loop:
		if _midi_wait == 0:
			while True:
				event = _midi[_midi_tt]
				_midi_tt += 1
				if event.type == Note:
					if event.velocity == 0:
						if (event.number, event.track) in _midi_active:
							_midi_active.pop((event.number, event.track))
					else:
						_midi_active[(event.number, event.track)] = event.velocity
				elif event.type == Wait:
					_midi_wait = int(event.value*8000)
					break
				elif event.type == End:
					_midi_loop = False
					break
		else:
			_midi_wait -= 1
		
		return [[idx[0], idx[1], _midi_active[idx]] for idx in _midi_active]

"""
Lit le fichier MIDI donné en argument de la commande.
Retourne, pour chaque échantillon, la liste des notes sous la forme [piste, note, amplitude].
"""
class Midi:
	def __init__(self, sampling=16000):
		self.sampling = sampling

	def __iter__(self):
		self.active = {}
		self.wait = 0
		self.tt = 0
		self.loop = True
		self.events = midi_events()
		return self

	def __next__(self):
		if self.loop:
			if self.wait == 0:
				while True:
					event = self.events[self.tt]
					self.tt += 1
					if event.type == Note:
						if event.velocity == 0:
							if (event.track, event.number) in self.active:
								self.active.pop((event.track, event.number))
						else:
							sys.stderr.write("Piste="+str(event.track)+"  Note="+str(event.number)+"  Force="+str(event.velocity)+"\n")
							self.active[(event.track, event.number)] = event.velocity
					elif event.type == Wait:
						self.wait = int(event.value*self.sampling/2)
						break
					elif event.type == End:
						self.loop = False
						break
			else:
				self.wait -= 1
			
			return [[idx[0], idx[1], self.active[idx]] for idx in self.active]
		raise StopIteration

def read_midi(filename, tempo):
	mid = mido.MidiFile(filename)
	result = []
	tracks = [0 for i in mid.tracks]
	tempo = [tempo for i in mid.tracks]
	wait = [None for i in mid.tracks]
	end = [False for i in mid.tracks]
	t = 0
	loop = True
	while loop:
		loop = False
		
		# Find the first events
		first = []
		firstt = None
		for i, track in enumerate(mid.tracks):
			if end[i]:
				continue
			if wait[i] == None:
				wait[i] = track[tracks[i]].time/tempo[i]/4
			
			if firstt == None or wait[i] < firstt:
				firstt = wait[i]
				first = [i]
			elif wait[i] == firstt:
				first.append(i)
		
		if firstt > 0:
			result.append(Wait(firstt))
		
		# Play the first events
		for i, track in enumerate(mid.tracks):
			if end[i]:
				continue
			loop = True
			msg = track[tracks[i]]
			if i in first:
				# Play event
				if msg.type == "set_tempo":
					tempo[i] = 6e7/msg.tempo
				elif msg.type == "note_on":
					result.append(Note(msg.note-50, msg.velocity/100, msg.channel, i))
				elif msg.type == "end_of_track":
					result.append(End())
					end[i] = True
					
				# Find next event
				tracks[i] += 1
				wait[i] = None
			else:
				wait[i] -= firstt
		
		if not (False in end):
			loop = False
		
	return result