-- credit: osmarks https://pastebin.com/ZP9Q1HCT

local Sound = require('sound')
local Util  = require('util')

local modules  = _G.peripheral.wrap('back')
local os       = _G.os
local parallel = _G.parallel

if not modules.launch or not modules.getMetaOwner then
  error([[Required:
* Kinetic augment
* Entity sensor
* Introspection module]])
end

local canvas = modules.canvas and modules.canvas()

local function display(meta)
  if canvas then
    if not canvas.group then
      canvas.group = canvas.addGroup({ 4, 90 })
      canvas.group.addRectangle(0, 0, 60, 30, 0x00000033)
      canvas.pitch = canvas.group.addText({ 4, 5 }, '') -- , 0x202020FF)
      canvas.pitch.setShadow(true)
      canvas.pitch.setScale(.75)
      canvas.group2 = canvas.addGroup({ 80, 10 })
      canvas.group2.addLines(
        { 0,   0 },
        { 0, 180 },
        { 5, 180 },
        { 5,   0 },
        0x202020FF,
        2)
      canvas.meter = canvas.group2.addRectangle(0, 0, 5, 1)
    end
    local size = math.abs(meta.pitch) -- math.ceil(math.abs(meta.pitch) / 9)
    local y = 0
    local color = 0x202020FF
    if meta.pitch < 0 then
      y = size
      color = 0x808080FF
    end
    canvas.meter.setPosition(0, 90 - y)
    canvas.meter.setSize(5, size)
    canvas.meter.setColor(color)
    canvas.pitch.setText(string.format('Pitch: %s\nMotion Y: %s\nSpeed: %s',
      math.floor(-meta.pitch),
      Util.round(meta.motionY, 2),
      Util.round(math.abs(meta.motionX) + math.abs(meta.motionY) + math.abs(meta.motionZ), 2)))
  end
end

local function clearDisplay()
  if canvas and canvas.group then
    canvas.group.remove()
    canvas.group = nil
    canvas.group2.remove()
  end
end

local function run()
  local launchCounter = 0

  while true do
    local meta = modules.getMetaOwner()

    if not meta.isSneaking and meta.isElytraFlying then

      if meta.pitch < 0 then -- looking up
        modules.launch(meta.yaw, meta.pitch, -meta.pitch / 22.5)
        Sound.play('entity.bobber.throw', .6)
        display(meta)
        os.sleep(0.1)

      elseif meta.motionY < -0.5 then -- falling fast
        modules.launch(0, 270, -meta.motionY + 1)
        Sound.play('entity.bat.takeoff')
        display(meta)
        os.sleep(0)

      else
        display(meta)
        os.sleep(0.1)
      end

    elseif meta.isSneaking and not meta.isElytraFlying and meta.pitch == -90 then
      if launchCounter < 2 then
        launchCounter = launchCounter + 1
        Sound.play('block.note.pling', .5)
        os.sleep(0.5)

      else
        Sound.play('entity.bobber.throw', 1)
        modules.launch(0, 270, 4)
        os.sleep(0.2)
      end

    elseif not meta.isSneaking and meta.motionY < -0.8 then
      print('falling...')
      modules.launch(0, 270, -meta.motionY + 1)
      Sound.play('entity.bat.takeoff')
      os.sleep(0)

    else
      clearDisplay()
      --display(meta)
      launchCounter = 0
      os.sleep(0.4)
    end
  end
end

parallel.waitForAny(
  function()
    print('\nFlight control initialized')
    print('\nSneak and look straight up for launch')
    print('Sneak to deactivate during flight')
    print('\nPress any key to exit')
    os.pullEvent('char')
  end,
  function()
    while true do
    local _, m = pcall(run)
      if m then
        print(m)
      end
      print('Waiting for 5 seconds before restarting')
      os.sleep(5)
    end
  end)