-- Lesson 27:  Music And MIDI.  The finished script, exactly as the lesson ends.
local NOTE_NAMES   = { "C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B" }
local MIDI_NOTE_ON = 0x90
local LOWEST       = 60
local HIGHEST      = 71
local HOLD_MS      = 400
local VOLUME_STEP  = 8

local theme  = musicLoad("Singe/menuIntro.flac")
local volume = 64

local target  = LOWEST
local heard   = "nothing yet"
local score   = 0
local inPort  = "none"
local outPort = "none"


function noteName(key)
    return NOTE_NAMES[(key % 12) + 1] .. (math.floor(key / 12) - 1)
end


function pickTarget()
    target = math.random(LOWEST, HIGHEST)
end


function playTarget()
    if not midiIsOutputOpen() then
        return
    end
    local key = target
    midiNoteOn(1, key, 100)
    timerAfter(HOLD_MS, function()
        midiNoteOff(1, key)
    end)
end


function setVolume(level)
    volume = math.min(128, math.max(0, level))
    musicSetVolume(volume)
end


function onInputPressed(what)
    if what == SWITCH_BUTTON1 then
        playTarget()
    elseif what == SWITCH_BUTTON2 then
        if musicIsPlaying(theme) then
            musicPause(theme)
        else
            musicResume(theme)
        end
    elseif what == SWITCH_BUTTON3 then
        if musicIsPlaying(theme) then
            musicStop(theme, 2000)
        else
            musicPlay(theme, -1)
        end
    elseif what == SWITCH_UP then
        setVolume(volume + VOLUME_STEP)
    elseif what == SWITCH_DOWN then
        setVolume(volume - VOLUME_STEP)
    end
end


function onMidiMessage(status, data1, data2, bytes)
    if (status & 0xF0) ~= MIDI_NOTE_ON or data2 == 0 then
        return
    end
    heard = noteName(data1)
    if data1 == target then
        score = score + 1
        pickTarget()
        playTarget()
    end
end


function onOverlayUpdate()
    overlayClear()
    overlayPrint(2, 2, "Music: " .. (musicIsPlaying(theme) and "playing" or "stopped"))
    overlayPrint(2, 3, "Volume: " .. volume .. " of 128")
    overlayPrint(2, 5, "MIDI in:  " .. inPort)
    overlayPrint(2, 6, "MIDI out: " .. outPort)
    overlayPrint(2, 8, "Play this note: " .. noteName(target))
    overlayPrint(2, 9, "Last note heard: " .. heard)
    overlayPrint(2, 10, "Score: " .. score)
    overlayPrint(2, 12, "Up and down change the volume.")
    overlayPrint(2, 13, "Space sends the note out, Alt pauses, Shift fades out.")
    return OVERLAY_UPDATED
end


function onShutdown()
    midiCloseInput()
    midiCloseOutput()
    musicUnload(theme)
end


setVolume(volume)
musicPlay(theme, -1)

if midiInputCount() > 0 and midiOpenInput(0) then
    inPort = midiInputName(0)
end
if midiOutputCount() > 0 and midiOpenOutput(0) then
    outPort = midiOutputName(0)
end

pickTarget()