local ml = require 'melisma.lazy'

ml.util.openmodule(ml.functional)

local argv = ml.internal.argv
local device = argv[1]

if not device then
  print('Usage: melisma -C synth main.lua DEVICE')
  print('Available devices are:')

  for _,source in ipairs(ml.port.midi.sources()) do
    print('\t'..source)
  end

  os.exit(1)
end

local mport = ml.port.midi.input.open('midi-in')

print(string.format('Connecting device \'%s\'', device))
mport:connect(device)

local wt = ml.oscil.wavetable.saw()
wt = wt + wt:scale(2)

local size = 8
local active = replicate(false, size)
local allocs = replicate(nil, 128)
local oscil = replicate(bind(ml.oscil.init, wt, 0, 0), size)
local interp = replicate(bind(ml.interp.init, 0), size)

zip(ml.oscil.mapa, oscil, interp)

local mix = ml.mixer.init(table.unpack(oscil))
local delay = ml.delay.init(mix)
  :delay(0.2)
  :feedback(0.4)
  :wetdrymix(0.5)
  :gain(0.8)
local lowpass = ml.biquad.lowpass.init(delay)
  :cutoff(4000)
  :resonance(0.7)
local aport = ml.port.audio.output.open('audio-out', lowpass)
local dests = ml.port.audio.destinations()

fmap(bind(aport.connect, aport), dests)

local attack = 0.025
local release = 0.05

local function handle_on(key, vel)
  print('on', key)

  -- Check if this note is already on
  if allocs[key] then return end

  -- Find unused oscillator
  local i = nil
  for j = 1,size do
    if not active[j] then
      i = j
      break
    end
  end
  if not i then return end

  -- Play the note
  print('activate oscillator', i)
  active[i] = true
  allocs[key] = i
  interp[i]:linear(vel / 127.0, attack)

  local f = 440 * 2^((key - 57) / 12.0)
  print('frequency', f)
  oscil[i]:setf(f)
end

local function free(args)
  -- Mark the oscillator as unused after the note is released
  local i, key = table.unpack(args)
  print('free oscillator', i)
  active[i] = false
  allocs[key] = nil
end

local function handle_off(key)
  print('off', key)

  -- Find the oscillator
  local i = allocs[key]
  if not i then return end

  -- Stop playing the note
  print('deactivate oscillator', i)
  interp[i]:linear(0, release)
  ml.event.schedule(release, free, { i, key })
end

mport:callback(function(msg)
  local status = msg.status & 0xf0
  local key = msg.data1
  local vel = msg.data2

  print('received', status, key, vel)

  local off = 0x80
  local on = 0x90

  if status == off then
    handle_off(key)
    return
  end

  if status == on then
    handle_on(key, vel)
    return
  end
end)