TE induction furnace auto clear

local INTERFACES_NAMES = {}
local INTERFACES = {}

-- config loadable info
local REDSTONE_TRIGGER_SIDES = {}
local INTERFACE_PULL_DIRECTION = nil

function CanonicaliseSide(side)
    if (side == nil or #side < 3 or #side > 6) then
        return nil
    end

    local s = string.lower(side)
    if (s == "left" or s == "top" or s == "right" or s == "bottom" or s == "front" or s == "back") then
        return s
    end

    return nil
end

function CanonicaliseNSWE(dir)
    if (dir == nil or #dir < 3 or #dir > 6) then
        return nil
    end

    local s = string.lower(dir)
    if (s == "north" or s == "east" or s == "south" or s == "west" or s == "up" or s == "down") then
        return s
    end

    return nil
end

function SplitStringByComma(input_str)
    return string.gmatch(input_str, "([^,]+)")
end

function LoadConnectedInterfaces()
    INTERFACES_NAMES = {}
    INTERFACES = {}
    local modem_connections = peripheral.getNames("back")
    if (modem_connections == nil) then
        return
    end

    for k, peripheralName in pairs(modem_connections) do
        if (tostring(peripheralName):find("me_interface") ~= nil) then
            local methodTable = peripheral.wrap(peripheralName)
            if (methodTable ~= nil) then
                table.insert(INTERFACES, methodTable)
                table.insert(INTERFACES_NAMES, peripheralName)
            end
        end
    end
end

function LoadConfigInfo()
    if (not fs.exists("config")) then
        return false
    end

    local hFile = fs.open("config", "r")
    if (hFile == nil) then
        print("Failed to open config file")
        return false
    end

    local isFail = false
    REDSTONE_TRIGGER_SIDES = {}
    local rs_trig = hFile.readLine()
    if (rs_trig ~= nil and #rs_trig > 0) then
        for side in SplitStringByComma(rs_trig) do
            local realSide = CanonicaliseSide(side)
            if (realSide ~= nil) then
                table.insert(REDSTONE_TRIGGER_SIDES, realSide)
            else
                print("Invalid side in config: " .. realSide)
                isFail = true
            end
        end
    end

    INTERFACE_PULL_DIRECTION = nil
    local itf_pull_dir_raw = hFile.readLine()
    local itf_pull_dir = CanonicaliseNSWE(itf_pull_dir_raw)
    if (itf_pull_dir ~= nil) then
        INTERFACE_PULL_DIRECTION = itf_pull_dir
    else
        print("Invalid interface pull direction: " .. itf_pull_dir_raw)
        isFail = true
    end

    hFile.close()
    return not isFail and #REDSTONE_TRIGGER_SIDES > 0 and INTERFACE_PULL_DIRECTION ~= nil
end

function SaveConfigInfo()
    local hFile = fs.open("config", "w")
    if (hFile == nil) then
        print("Failed to open config file for writing")
        return
    end

    if (REDSTONE_TRIGGER_SIDES ~= nil) then
        local str = table.concat(REDSTONE_TRIGGER_SIDES, ",")
        hFile.writeLine(str)
        print("Writing to config: " .. str)
    else
        hFile.writeLine("")
    end

    if (INTERFACE_PULL_DIRECTION ~= nil) then
        hFile.writeLine(INTERFACE_PULL_DIRECTION)
        print("Writing to config: " .. INTERFACE_PULL_DIRECTION)
    else
        hFile.writeLine("")
    end
end

function SetupConfig()
    print("Input the sides on the computer that, when a redstone signal is received, will clear all induction furnaces")
    print("(comma separated list of: top, bottom, left, right, front or back)")
    term.write(">")

    local inputSides = {}
    local sides = read()
    for side in SplitStringByComma(sides) do
        local realSide = CanonicaliseSide(side)
        if (realSide == nil) then
            print("Invalid side: " .. side)
            return false
        end

        table.insert(inputSides, realSide)
    end

    print("Input the world direction of the induction furnaces, relative to the ME Interfaces")
    print("(top, bottom, north, east, south, west)")
    term.write(">")
    local pull_dir_raw = read()
    local pull_dir = CanonicaliseNSWE(pull_dir_raw)
    if (pull_dir == nil) then
        print("Invalid direction: " .. pull_dir_raw)
        return false
    end

    REDSTONE_TRIGGER_SIDES = inputSides
    INTERFACE_PULL_DIRECTION = pull_dir
    return true
end

function OnRedstoneInput()
    -- clear interfaces

    print("Clearing " .. #INTERFACES .. " induction furnaces at " .. INTERFACE_PULL_DIRECTION)
    for i, itf in pairs(INTERFACES) do
        itf.pullItem(INTERFACE_PULL_DIRECTION, 1)
        itf.pullItem(INTERFACE_PULL_DIRECTION, 2)
    end
end

function Main()
    if (not LoadConfigInfo()) then
        while (not SetupConfig()) do end
        SaveConfigInfo()
    end

    LoadConnectedInterfaces()
    print("Loaded " .. #INTERFACES .. " interfaces via modem connections")
    print("TIP1: To reset the config file, terminate the program and run 'rm config'")
    print("")
    print("TIP2: The ME interface must also be placed on the output of the induction furnaces (red, yellow or orange sides)")

    while true do
        os.pullEvent("redstone")

        local hasInput = false
        for i, side in pairs(REDSTONE_TRIGGER_SIDES) do
            if (rs.getInput(side)) then
                hasInput = true
                break
            end
        end

        if (hasInput) then
            OnRedstoneInput()
            print("[" .. os.clock() .. "] Redstone received!")
        end
    end
end

Main()