local poweredClimb = 0
local glideClimb = 0
local lastAltitude
local lastVoiceState = -1

local engineSwitch
local resetSwitch
local altSensorIndex
local energy
local voiceSwitch
local alarmStep

local sensorIDs
local sensorParams
local sensorLabels

local function toCapacity(climb)
    return 100 * climb / energy
end

local function onEngineSwitchChanged(value)
    engineSwitch = system.getInputsVal(value) ~= 0 and value or nil
    system.pSave("enginesw", engineSwitch)
end

local function onResetSwitchChanged(value)
    resetSwitch = system.getInputsVal(value) ~= 0 and value or nil
    system.pSave("resetsw", resetSwitch)
end

local function onAltSensorIndexChanged(value)
    altSensorIndex = value - 1
    system.pSave("altidx", altSensorIndex)
end

local function onEnergyChanged(value)
    energy = value
    system.pSave("energy", energy)
end

local function onVoiceSwitchChanged(value)
    voiceSwitch = system.getInputsVal(value) ~= 0 and value or nil
    system.pSave("voicesw", voiceSwitch)
end

local function onAlarmStepChanged(value)
    alarmStep = value
    system.pSave("alarmstp", alarmStep)
end

local function initForm()
    form.addRow(2)
    form.addLabel({ label = "Engine" })
    form.addInputbox(engineSwitch, false, onEngineSwitchChanged)
    form.addRow(2)
    form.addLabel({ label = "Altitude sensor" })
    form.addSelectbox(sensorLabels, altSensorIndex + 1, true, onAltSensorIndexChanged)
    form.addRow(3)
    form.addLabel({ label = "100% battery = ", width = 180 })
    form.addIntbox(energy, 1, 30000, 500, 0, 1, onEnergyChanged)
    form.addLabel({ label = "m", alignRight = true })
    form.addRow(3)
    form.addLabel({ label = "Alarm step", width = 180 })
    form.addIntbox(alarmStep, 1, 50, 10, 0, 1, onAlarmStepChanged)
    form.addLabel({ label = "%", alignRight = true })
    form.addRow(2)
    form.addLabel({ label = "Voice announcement" })
    form.addInputbox(voiceSwitch, false, onVoiceSwitchChanged)
    form.addRow(2)
    form.addLabel({ label = "Reset" })
    form.addInputbox(resetSwitch, false, onResetSwitchChanged)
end

local function printTelemetry(width, height)
    local text1 = string.format("%.1fm powered", poweredClimb)
    local text2 = string.format("%.1fm thermal", glideClimb)
    lcd.drawText(width - 5 - lcd.getTextWidth(FONT_NORMAL, text1), 5, text1)
    lcd.drawText(width - 5 - lcd.getTextWidth(FONT_NORMAL, text2), 10 + lcd.getTextHeight(FONT_NORMAL), text2)
end

local function init()
    sensorIDs = {}
    sensorParams = {}
    sensorLabels = {"..."}
    for _,sensor in ipairs(system.getSensors()) do
        if sensor.param ~= 0 and sensor.type ~= 5 and sensor.type ~= 9 then
            sensorIDs[#sensorIDs+1] = sensor.id
            sensorParams[#sensorParams+1] = sensor.param
            sensorLabels[#sensorLabels+1] = string.format("%s: %s [%s]", sensor.sensorName, sensor.label, sensor.unit)
        end
    end
    engineSwitch = system.pLoad("enginesw")
    resetSwitch = system.pLoad("resetsw")
    altSensorIndex = system.pLoad("altidx", 0)
    energy = system.pLoad("energy", 500)
    alarmStep = system.pLoad("alarmstp", 10)
    voiceSwitch = system.pLoad("voicesw")
    if altSensorIndex > #sensorIDs then altSensorIndex = 0 end

    system.registerForm(1, MENU_APPS, "Calculated Capacity", initForm)
    system.registerTelemetry(2, "Calculated Capacity", 2, printTelemetry)
end

local function loop()
    local voicesw = voiceSwitch and system.getInputsVal(voiceSwitch) or -1
    if voicesw == 1 and lastVoiceState ~= 1 then
        system.playNumber(100 - toCapacity(poweredClimb), 0, "%", "Capacity")
    end
    lastVoiceState = voicesw
    if system.getInputsVal(resetSwitch) == 1 then
        poweredClimb = 0
        glideClimb = 0
    end
    local altitude = altSensorIndex ~= 0 and system.getSensorValueByID(sensorIDs[altSensorIndex], sensorParams[altSensorIndex]) or nil
    if altitude and altitude.valid and lastAltitude then
        if system.getInputsVal(engineSwitch) == 1 and altitude.value > lastAltitude then
            poweredClimb = poweredClimb + altitude.value - lastAltitude
            if toCapacity(poweredClimb) // alarmStep > toCapacity(poweredClimb + lastAltitude - altitude.value) // alarmStep then -- next step
                -- ALARM
                system.playNumber((100 - toCapacity(poweredClimb + lastAltitude - altitude.value)) // alarmStep * alarmStep, 0, "%", "Capacity")
            end
        elseif system.getInputsVal(engineSwitch) == -1 and altitude.value > lastAltitude then
            glideClimb = glideClimb + altitude.value - lastAltitude
        end
    end
    lastAltitude = (altitude and altitude.valid) and altitude.value or nil
end

return { init = init, loop = loop, author = "LeonAir RC", version = "1.1.0", name = "Calculated Capacity" }