ComputerCraft Synthesizer

local bass = peripheral.wrap("left")
local treble = peripheral.wrap("right")

local monitor = peripheral.wrap("top")
term.redirect(monitor)
term.clear()
monitor.setTextScale(.5)
monitor.setBackgroundColor(colors.gray)
monitor.clear()

local chordMode = false

local keys = {
    ["cSharp"] = {window.create(monitor, 4, 0, 3, 7, true), 8},
    ["dSharp"] = {window.create(monitor, 9, 0, 3, 7, true), 10},
    ["fSharp"] = {window.create(monitor, 19, 0, 3, 7, true), 13},
    ["gSharp"] = {window.create(monitor, 24, 0, 3, 7, true), 15},
    ["aSharp"] = {window.create(monitor, 29, 0, 3, 7, true), 17},
    ["c"] = {window.create(monitor, 1, 0, 4, 15, true), 7},
    ["d"] = {window.create(monitor, 6, 0, 4, 15, true), 9},
    ["e"] = {window.create(monitor, 11, 0, 4, 15, true), 11},
    ["f"] = {window.create(monitor, 16, 0, 4, 15, true), 12},
    ["g"] = {window.create(monitor, 21, 0, 4, 15, true), 14},
    ["a"] = {window.create(monitor, 26, 0, 4, 15, true), 16},
    ["b"] = {window.create(monitor, 31, 0, 4, 15, true), 18},
    ["c2"]  = {window.create(monitor, 36, 0, 4, 15, true), 19},
}

local chordButton = window.create(monitor, 45, 10, 10, 5)

for k, v in pairs(keys) do
    v = v[1]
    if not k:find("Sharp") then
        v.setBackgroundColor(colors.white)
        v.clear()
    end
end
for k, v in pairs(keys) do
    v = v[1]
    if k:find("Sharp") then
        v.setBackgroundColor(colors.black)
        v.clear()
    end
end
chordButton.setBackgroundColor(colors.red)
chordButton.clear()

function checkKey(x, y)
    for k, v in pairs(keys) do
        v = v[1]
        if k:find("Sharp") then
            local vPosX, vPosY = v.getPosition()
            if x >= vPosX and y >= vPosY and x <= vPosX+2 and y <= vPosY+6 then
                return k
            end
        elseif not k:find("Sharp") then
            local vPosX, vPosY = v.getPosition()
            if x >= vPosX and y >= vPosY and x <= vPosX+3 and y <= vPosY+14 then
                return k
            end
        else
            return false
        end
    end
end

function checkChordButton(x, y)
    local vPosX, vPosY = chordButton.getPosition()
    if x >= vPosX and y >= vPosY and x <= vPosX+9 and y <= vPosY+4 then
        if not chordMode then
            chordMode = true
            chordButton.setBackgroundColor(colors.green)
            chordButton.clear()
        else
            chordMode = false
            chordButton.setBackgroundColor(colors.red)
            chordButton.clear()
        end
        return true
    end
    return false
end

while true do
    event, side, xPos, yPos = os.pullEvent("monitor_touch")
    if not checkChordButton(xPos, yPos) then
        local keyHit = checkKey(xPos, yPos)
        if keyHit then
            local root = keys[keyHit][2]
            local majThird = root
            local perfFifth = root
            if root <= 17 then
                majThird = root+4
                perfFifth = root+7
            end
            if chordMode == false then
                bass.playNote("bass", 2, root)
                treble.playNote("harp", 2, root)
            else
                bass.playNote("bass", 2, root)
                bass.playNote("bass", 2, majThird)
                bass.playNote("bass", 2, perfFifth)
                treble.playNote("harp", 2, majThird)
                treble.playNote("harp", 2, perfFifth)
                treble.playNote("harp", 2, root)
            end
        end
    end
end