RedstoneRelay

term.clear()
term.setCursorPos(1, 1)
print("The control program has been launched...")

local mon = peripheral.wrap("monitor_4")
local relay = peripheral.wrap("redstone_relay_1")

if not mon or not relay then
    error("Error: Check names monitor_4 and redstone_relay_1!")
end

mon.setBackgroundColor(colors.black)
mon.clear()

local RELAY_SIDE = "top"
relay.setAnalogOutput("top", 15)

mon.setTextScale(1)

local currentPower = 15

local ENGINES_COUNT = 1
local SAILS_COUNT = 8

local BASE_SAILS_COUNT = 8
local MAX_AIRFLOW_PER_ENGINE = 31.68
local MAX_LIFT_PER_ENGINE = 138.23
local MAX_EFFECTIVE_REDUCTION = 14

local btnMinus = {x1 = 2, y1 = 2, x2 = 5, y2 = 4}
local btnPlus = {x1 = 14, y1 = 2, x2 = 17, y2 = 4}

local function calculateStats(power)
    local effectivePower = math.max(power, 1)
    local airflowRatio = SAILS_COUNT / BASE_SAILS_COUNT

    local airflowPerEngine = (15 - effectivePower)
        * (MAX_AIRFLOW_PER_ENGINE / MAX_EFFECTIVE_REDUCTION)
        * airflowRatio

    local liftPerEngine = airflowPerEngine
        * (MAX_LIFT_PER_ENGINE / MAX_AIRFLOW_PER_ENGINE)

    return {
        airflow = airflowPerEngine,
        lift = liftPerEngine * ENGINES_COUNT,
    }
end

local function drawButton(x1, y1, x2, y2, color, text)
    mon.setBackgroundColor(color)
    mon.setTextColor(colors.white)

    for y = y1, y2 do
        mon.setCursorPos(x1, y)
        mon.write(string.rep(" ", x2 - x1 + 1))
    end

    mon.setCursorPos(
        x1 + math.floor((x2 - x1) / 2),
        y1 + math.floor((y2 - y1) / 2)
    )
    mon.write(text)
end

local function drawUI()
    local stats = calculateStats(currentPower)

    mon.setBackgroundColor(colors.black)
    mon.clear()

    drawButton(btnMinus.x1, btnMinus.y1, btnMinus.x2, btnMinus.y2, colors.red, "-")
    drawButton(btnPlus.x1, btnPlus.y1, btnPlus.x2, btnPlus.y2, colors.green, "+")

    mon.setBackgroundColor(colors.black)

    mon.setTextColor(colors.yellow)
    mon.setCursorPos(8, 3)
    mon.write(string.format("PW: %02d", currentPower))

    mon.setTextColor(colors.cyan)
    mon.setCursorPos(2, 6)
    mon.write(string.format("Engines: %d", ENGINES_COUNT))

    mon.setCursorPos(2, 7)
    mon.write(string.format("Sails: %d", SAILS_COUNT))

    mon.setCursorPos(2, 9)
    mon.write(string.format("Air: %.2f m/s", stats.airflow))

    mon.setCursorPos(2, 10)
    mon.write(string.format("Lift: %.2f kg", stats.lift))
end

local function updateSignal()
    relay.setAnalogOutput(RELAY_SIDE, currentPower)
    drawUI()
end

drawUI()
updateSignal()

while true do
    local _, side, x, y = os.pullEvent("monitor_touch")

    if side == "monitor_4" then
        if x >= btnMinus.x1 and x <= btnMinus.x2 and y >= btnMinus.y1 and y <= btnMinus.y2 then
            if currentPower > 0 then
                currentPower = currentPower - 1
                updateSignal()
            end
        elseif x >= btnPlus.x1 and x <= btnPlus.x2 and y >= btnPlus.y1 and y <= btnPlus.y2 then
            if currentPower < 15 then
                currentPower = currentPower + 1
                updateSignal()
            end
        end
    end
end