Computercraft - Supports API

local registeredCheckedFeatures = {}

registerCheckedFeatured = function(checkedFeatureName, checkedFeatureFunc)
    if checkedFeatureName == nil or type(checkedFeatureName) ~= "string" or string.len(checkedFeatureName) == 0 or checkedFeatureFunc == nil or type(checkedFeatureFunc) ~= "function" or registeredCheckedFeatures[checkedFeatureName] ~= nil then
        return false
    end

    registeredCheckedFeatures[checkedFeatureName] = checkedFeatureFunc

    return true
end

unregisterCheckedFeature = function(checkedFeatureName)
    if checkedFeatureName == nil or type(checkedFeatureName) ~= "string" or string.len(checkedFeatureName) == 0 or registeredCheckedFeatures[checkedFeatureName] == nil then
        return false
    end

    registeredCheckedFeatures[checkedFeatureName] = nil

    return true
end

local checkPeripheralSupport = function(requiredPeripheralName)
    for key, value in pairs(peripheral.getNames()) do
        if peripheral.getType(value) == requiredPeripheralName then
            return true
        end
    end

    return false
end

features = function(requiredFeatures)
    if requiredFeatures == nil or type(requiredFeatures) ~= "table" then
        return false
    end

    local hasRequiredFeatures = true
    local missingRequiredFeatures = {}

    for requiredFeatureIndex, requiredFeatureName in pairs(requiredFeatures) do
        if registeredCheckedFeatures[requiredFeatureName] ~= nil then
            if not registeredCheckedFeatures[requiredFeatureName]() then
                hasRequiredFeatures = false
                missingRequiredFeatures[table.getn(missingRequiredFeatures) + 1] = requiredFeatureName
            end
        else
            if not checkPeripheralSupport(requiredFeatureName) then
                hasRequiredFeatures = false
                missingRequiredFeatures[table.getn(missingRequiredFeatures) + 1] = requiredFeatureName
            end
        end
    end

    return hasRequiredFeatures, missingRequiredFeatures
end

displayMissingRequirements = function(missingRequiredFeatures)
    print("You are missing the following required features to run this program. Please add the missing features and restart the program.\n")

    for missingRequiredFeatureIndex, missingRequiredFeature in pairs(missingRequiredFeatures) do
        print(missingRequiredFeature)
    end
end

local hasTurtleSupport = function()
    return turtle ~= nil
end

local getFreeTurtleInventorySlot = function()
    local freeTurtleInventorySlot = -1

    if hasTurtleSupport() then
        for turtleInventorySlot = 1, 16, 1 do
            if turtle.getItemCount(turtleInventorySlot) == 0 then
                freeTurtleInventorySlot = turtleInventorySlot
                break
            end
        end
    end

    return freeTurtleInventorySlot
end

local hasItemInTurtleInventorySlot = function(turtleInventorySlot, requiredItemName)
    if turtleInventorySlot == nil or type(turtleInventorySlot) ~= "number" or turtleInventorySlot <= 0 or turtleInventorySlot >= 17 or requiredItemName == nil or type(requiredItemName) ~= "string" or string.len(requiredItemName) == 0 then
        return false
    end

    if hasTurtleSupport() then
        local turtleInventoryItemDetails = turtle.getItemDetail(turtleInventorySlot)

        if turtleInventoryItemDetails then
            return string.lower(turtleInventoryItemDetails.name) == string.lower(requiredItemName)
        end
    end

    return false
end

local hasItemInTurtleEquipmentSide = function(turtleEquipSide, requiredItemName)
    if turtleEquipSide == nil or type(turtleEquipSide) ~= "string" or string.len(turtleEquipSide) == 0 or requiredItemName == nil or type(requiredItemName) ~= "string" or string.len(requiredItemName) == 0 then
        return false
    end

    if hasTurtleSupport() then
        local freeTurtleInventorySlot = getFreeTurtleInventorySlot()

        if freeTurtleInventorySlot >= 1 and freeTurtleInventorySlot <= 16 then
            local previousTurtleInventorySlot = turtle.getSelectedSlot()
            local foundRequiredItem = false
            turtle.select(freeTurtleInventorySlot)

            if string.lower(turtleEquipSide) == "left" then
                turtle.equipLeft()
                foundRequiredItem = hasItemInTurtleInventorySlot(freeTurtleInventorySlot, requiredItemName)
                turtle.equipLeft()
            elseif string.lower(turtleEquipSide) == "right" then
                turtle.equipRight()
                foundRequiredItem = hasItemInTurtleInventorySlot(freeTurtleInventorySlot, requiredItemName)
                turtle.equipRight()
            end

            turtle.select(previousTurtleInventorySlot)
            return foundRequiredItem
        end
    end

    return false
end

local hasTurtleEquippedItem = function(requiredItemName)
    return hasItemInTurtleEquipmentSide("right", requiredItemName) or hasItemInTurtleEquipmentSide("left", requiredItemName)
end

local hasMeleeSupport = function()
    return hasTurtleEquippedItem("minecraft:diamond_sword")
end

local hasMiningSupport = function()
    return hasTurtleEquippedItem("minecraft:diamond_pickaxe")
end

local hasDiggingSupport = function()
    return hasTurtleEquippedItem("minecraft:diamond_shovel")
end

local hasFellingSupport = function()
    return hasTurtleEquippedItem("minecraft:diamond_axe")
end

local hasFarmingSupport = function()
    return hasTurtleEquippedItem("minecraft:diamond_hoe")
end

local hasCraftingSupport = function()
    return hasTurtleSupport() and turtle.craft ~= nil
end

local hasWirelessModemSupport = function()
    for key, value in pairs(peripheral.getNames()) do
        if peripheral.getType(value) == "modem" then
            local modem = peripheral.wrap(value)
            if modem.isWireless() then
                return true
            end
        end
    end

    return hasTurtleEquippedItem("computercraft:cc-peripheral")
end

local hasWiredModemSupport = function()
    for key, value in pairs(peripheral.getNames()) do
        if peripheral.getType(value) == "modem" then
            local modem = peripheral.wrap(value)
            if not modem.isWireless() then
                return true
            end
        end
    end

    return false
end

local hasAdvancedSupport = function()
    return term.isColor()
end

local hasMonitorSupport = function()
    return checkPeripheralSupport("monitor")
end

local hasModemSupport = function()
    return checkPeripheralSupport("modem")
end

local hasPrinterSupport = function()
    return checkPeripheralSupport("printer")
end

local hasDriveSupport = function()
    return checkPeripheralSupport("drive")
end

registerCheckedFeatured("turtle", hasTurtleSupport)
registerCheckedFeatured("melee", hasMeleeSupport)
registerCheckedFeatured("mining", hasMiningSupport)
registerCheckedFeatured("digging", hasDiggingSupport)
registerCheckedFeatured("felling", hasFellingSupport)
registerCheckedFeatured("farming", hasFarmingSupport)
registerCheckedFeatured("crafty", hasCraftingSupport)
registerCheckedFeatured("wireless", hasWirelessModemSupport)
registerCheckedFeatured("wired", hasWiredModemSupport)
registerCheckedFeatured("advanced", hasAdvancedSupport)
registerCheckedFeatured("monitor", hasMonitorSupport)
registerCheckedFeatured("modem", hasModemSupport)
registerCheckedFeatured("printer", hasPrinterSupport)
registerCheckedFeatured("drive", hasDriveSupport)