Elevator Control for Minecraft

--[[
Elevator Control by Hamish Robertson
Aliases: OminousPenguin, MC username: Peren

Thanks to Jonnathon Clayton for identifying a replacement for Rednet Cables (Project Red)

Licence: Creative Commons Attribution-NonCommercial-ShareAlike (http://creativecommons.org/licenses/by-nc-sa/3.0/)

This is a LUA program for ComputerCraft, a Minecraft mod by Daniel Ratcliffe aka dan200 (http://www.computercraft.info/)
This program is for controlling elevators from the Railcraft mod (http://www.railcraft.info/)
For help and feedback please use this forum thread: http://www.computercraft.info/forums2/index.php?/topic/1302-railcraft-mod-elevator-control/

The following four variables can be used to specify details of the wiring you have used:
--]]

bundleSide = "bottom" -- The side of the computer to which the bundled cable is attached
elevatorWire = "purple" -- Colour of insulated wire from bundled cable to back of elevator track. Purple = 10th color on rednet cable
detetctorWire = "white" -- Colour of insulated wire from bundled cable to cart detector. White = default color on rednet cable
boardingWire = "lime" -- Colour of insulated wire from bundled cable to boarding rail. Lime = 5th color on rednet cable

--[[
Use Ctrl+T to terminate the program.

You do not need to change anything below this point.

You are permitted to modify and or build upon this work.
If you make your own version publicly available, then please also publish it at the above forum thread. Thank you and happy coding!
--]]

version = "2.3.1"

function writeToPos(x, y, str)
    term.setCursorPos(x, y)
    term.write(str)
end

function updateMenu()
    term.clear()
    local selected = 1
    writeToPos(4, 2, "Current version: "..version)
    writeToPos(5, 3, "Latest version: "..latestVersion)
    writeToPos(4, 5, "Please select one of the following options:")
    writeToPos(6, 7, "[x] Update all elevators within range")
    writeToPos(6, 8, " x  Update this elevator")
    writeToPos(1, 19, "Arrow keys change selection    Backspace to go back")

    local function changeSelection(previousSelection)
        writeToPos(6,6+previousSelection," x ")
        writeToPos(6,6+selected,"[x]")
    end

    local keyHandlers = {
        [200] = function () -- up arrow
            if selected == 2 then
                selected = 1
                changeSelection(2)
            end
        end,

        [208] = function () -- down arrow
            if selected == 1 then
                selected = 2
                changeSelection(1)
            end
        end,

        [28] = function () -- enter/return
            transmit(CHANNEL_ELEVATOR, os.getComputerID(), "UPDATE", (selected == 1))
            doUpdate()
        end,

        [14] = function () -- backspace
            return true
        end
    }

    while true do
        _, keycode = os.pullEvent("key")
        f = keyHandlers[keycode]
        if type(f) == "function" then
            if f() then return end
        end
    end
end -- updateMenu()

function doUpdate()
    if updateAvailable then
        if shell.run("pastebin", "get", "iJWyUQVr", "elevator-main-update.lua") then
            fs.delete("elevator-main.lua")
            fs.move("elevator-main-update.lua", "elevator-main.lua")
            os.reboot()
        end
    end
end

function unserialise(s)
    local t = {}
    t.heights = {}
    mt = {
        -- The table t uses the y coord as it's indices which are therefore not contiguous and so the retrevial order can not be relied upon.
        -- The 'heights' table is a contiguously indexed array whos values are the y coords of each floor. This enables us to sort the floors into (reverse) height order.
        __newindex = function(t,k,v)
            t.heights[#t.heights+1] = k -- k is the height coordinate of the floor
            rawset(t,k,v)
        end
    }
    setmetatable(t, mt)
    for u in string.gmatch(s, "[^\030]+") do
        local iter = string.gmatch(u, "([^\031]+)")
        t[tonumber(iter())] = iter()
    end
    return t
end

function serialise(t)
    local s = ""
    for i=1,#t.heights do
        s = s..t.heights[i].."\031"..t[t.heights[i]].."\030"
    end
    return s
end

function addFloor(sMessage)
    local iter = string.gmatch(sMessage, "([^\031]+)")
    local y,label = tonumber(iter()),iter()
    floors[y] = label
    newFloorTimer = os.startTimer(3)
end

function sortReverse(t)
    table.sort(t.heights, function (a,b) return (a > b) end)
    for i=1,#t.heights do
        if t.heights[i] == y then
            t.heights.y = i; break -- t.heights.y stores the index of the current floor in the t.heights table
            -- t.heights[t.heights.y] would give the y coordinate of the current floor
            -- t[t.heights[t.heights.y]] would give the text label of the current floor
        end
    end
end

function transmit(sChannel, sReplyChannel, sMessage, tBroadcast)
    -- tBroadcast optionaly specifies that "ALL" should be used instead of the elevator ID
    -- Messages are sent in this format: "ELEV" elevID/"ALL" messageID [messageBody]
    modem.close(sChannel)
    modem.transmit(sChannel, sReplyChannel, "ELEV\030"..(tBroadcast and "ALL" or elevID).."\030"..sMessage)
    modem.open(sChannel)
end

function pause()
    print ("Press any key to continue...")
    os.pullEvent("key")
end

eventHandlers = {
    modemFunctions = {
        ["DISCOVER"] = function (sReplyChannel)
        -- Respond to elevator ID discovery request
            transmit(sReplyChannel, CHANNEL_ELEVATOR, "ID") -- No need for broadcast flag as the code in setup.lua doesn't filter based on elevID
        end,

        --["ID"] This function doesn't exist here as these messages are only for the setup program

        ["ANNOUNCE"] = function (sReplyChannel, sMessage)
        -- Received new floor announcement broadcast
            -- Add floor to local table
            addFloor(sMessage)
            -- Send reply of own y and label
            transmit(sReplyChannel, CHANNEL_ELEVATOR, "REPLY\030"..y.."\031"..floors[y])
        end,

        ["REPLY"] = function (_, sMessage)
        -- Received a reply to own announcement
            addFloor(sMessage)
        end,

        ["ACTIVATE"] = function (sReplyChannel, sMessage)
        -- Elevator activation message from another floor
            acceptInput = false
            -- Check if this floor is the destination
            if tonumber(sMessage) == y then
                ignoreDetector = false
                redstone.setBundledOutput(bundleSide, colors[elevatorWire])
                term.clear()
                writeToPos(19,7,"Incoming cart")
                writeToPos(15,9,"Please clear the track")
            else
                displayBusy()
            end
        end,

        ["CALL"] = function ()
        -- Received cart call message
            acceptInput = false
            displayBusy()
            -- Pulse the boarding rail to send any cart that might be on it
            redstone.setBundledOutput(bundleSide, colors[boardingWire])
            sleep(1)
            redstone.setBundledOutput(bundleSide, 0)
        end,

        ["CLEAR"] = function ()
        -- Recaived notifcation that a cart has arrived at another floor (and so the elevator is probably clear for use)
            if departedTimer then departedTimer = nil end
            acceptInput = true
            renderFloorList(true)
        end,

        ["UPDATE"] = function (sReplyChannel, _, eID)
            if not ignoreUpdates then
                ignoreUpdates = true
                ignoreUpdateTimer = os.startTimer(10)
                transmit(CHANNEL_ELEVATOR, sReplyChannel, "UPDATE", eID == "ALL")
                doUpdate()
            end
        end
    },

    modem_message =
        function (_, sChannel, sReplyChannel, sMessage)
            if sChannel == CHANNEL_ELEVATOR or sChannel == os.getComputerID() then
                local iter = string.gmatch(sMessage, "([^\030]+)")
                if iter() ~= "ELEV" then return end -- Right channel but not meant for us
                local eID = iter()
                if eID == elevID or eID == "ALL" then -- Correct elevID or message is for all elevators
                    local f = eventHandlers.modemFunctions[iter()]
                    if type(f) == "function" then
                        return f(sReplyChannel, iter(), eID) -- iter() = rest of the message
                    end
                end

            -- Reply to GPS ping if we know our full coords
            elseif z and sChannel == gps.CHANNEL_GPS and sMessage == "PING" then
                modem.transmit(sReplyChannel, gps.CHANNEL_GPS, textutils.serialize({x,y,z}))
            end
        end,

    key =
        function (keycode)
            if acceptInput then
                if (keycode == 200) then -- up
                    if selected > 1 then
                        if selected-1 == floors.heights.y then
                            if selected > 2 then selected = selected-2 end
                        else
                            selected = selected-1
                        end
                        renderFloorList()
                    end
                elseif (keycode == 208) then -- down
                    if selected < #floors.heights then
                        if selected+1 == floors.heights.y then
                            if selected < #floors.heights-1 then selected = selected+2 end
                        else
                            selected = selected+1
                        end
                        renderFloorList()
                    end
                elseif (keycode == 57) then -- Space
                    ignoreDetector = false
                    acceptInput = false
                    redstone.setBundledOutput(bundleSide, colors[elevatorWire])
                    transmit(CHANNEL_ELEVATOR, os.getComputerID(), "CALL")
                    term.clear()
                    writeToPos(20,8,"Cart called")
                elseif keycode == 28 and selected ~= floors.heights.y then -- enter
                    transmit(CHANNEL_ELEVATOR, os.getComputerID(), "ACTIVATE\030"..floors.heights[selected])
                    redstone.setBundledOutput(bundleSide, colors[boardingWire])
                    acceptInput = false
                    term.clear()
                    writeToPos(20,8,"Bon Voyage")
                    writeToPos(20,10,"Press Esc")
                    sleep(1)
                    redstone.setBundledOutput(bundleSide, 0)
                    departedTimer = os.startTimer(2)
                elseif keycode == 22 then -- U for update menu
                    updateMenu()
                    renderFloorList()
                end
            end
        end,

    timer =
        function (timerID)
            if timerID == newFloorTimer then
                newFloorTimer = nil
                sortReverse(floors)
                local file = io.open("elevator.cfg", "w")
                file:write(modemSide.."\n")
                file:write(elevID.."\n")
                file:write(coords.."\n")
                file:write(serialise(floors).."\n")
                file:write(bundledConnector)
                file:close()
                renderFloorList(true)
            elseif timerID == departedTimer then
                departedTimer = nil
                displayBusy()
            elseif timerID == ignoreUpdateTimer then
                ignoreUpdates = false
            end
        end,

    redstone =
        function()
            if ignoreDetector == false and colors.test(redstone.getBundledInput(bundleSide), colors[detetctorWire]) then
                ignoreDetector = true
                transmit(CHANNEL_ELEVATOR, os.getComputerID(), "CLEAR")
                redstone.setBundledOutput(bundleSide, 0)
                renderFloorList(true)
            end
        end,

    handle =
        function (self, f, ...)
            f = self[f]
            if type(f) == "function" then return f(...) end
        end
}

function displayBusy()
    term.clear()
    writeToPos(19,7,"Elevator busy")
    writeToPos(20,9,"Please wait")
end

function renderFloorList(reset)
    if reset then selected = floors.heights.y end
    term.clear()
    if updateAvailable then
        writeToPos(30,1,"New version available!")
        writeToPos(33,2,"Press U for options")
    end
    local startIndex, line = 1, 1
    if selected > 9 then
        startIndex = selected - 8
    else
        line = 10 - selected
    end

    for i=startIndex,#floors.heights do
        term.setCursorPos(13-(tostring(floors.heights[i]):len()),line)
        term.write(floors.heights[i]..": "..floors[floors.heights[i]])
        line = line + 1
        if line == 17 then break end -- If we get to the bottom of the screen, stop printing floors
    end

    if selected ~= floors.heights.y then
        midMarkL, midMarkR = ">", "<"
        line = 9 - (selected - floors.heights.y) -- Eg we're on 20, selected is 19: 19 is now at line 9, 20 is at 10 which is 9 - (-1)
        writeToPos(8,line,"-")
        writeToPos(42,line,"-")
    else
        midMarkL, midMarkR = "-", "-"
    end
    writeToPos(8,9,midMarkL)
    writeToPos(42,9,midMarkR)

    writeToPos(2,18,"Up/Down arrow keys to select destination")
    writeToPos(2,19,"Press Enter to activate         Space to call cart")
    acceptInput = true;
end -- renderFloorList()

function initialise()
    response = http.get("http://pastebin.com/raw.php?i=r3mt8mDD")
    if response then
        latestVersion = response.readLine()
        response.close()
        if latestVersion ~= version then
            updateAvailable = true
        end
    end

    CHANNEL_ELEVATOR = 34080
    acceptInput, ignoreDetector, newFloorTimer, departedTimer, ignoreUpdates, ignoreUpdateTimer = false, true, nil, nil, false, nil
    dir = shell.getRunningProgram(); i = string.find(dir, "/")
    if i then
        config = dir:sub(1,i).."/elevator.cfg"
    else
        config = "elevator.cfg"
    end
    file = assert(io.open(config, "r"), "Failed to open "..config.."\nRun setup.lua first")
    modemSide,elevID,coords,floors,bundledConnector = file:read("*l"),file:read("*l"),file:read("*l"),file:read("*l"),file:read("*l");file:close()

    if (bundledConnector == nil) then
        term.clear()
        writeToPos(3, 4, "Are you using the Bundled Connector")
        writeToPos(6, 6, "from the Extra Peripherals mod? [Y/n] ")
        bundledConnector = string.lower(string.sub(io.read(),1,1))
        if (bundledConnector=='y') then
            bundledConnector = 'bundledConnector:yes'
        else
            bundledConnector = 'bundledConnector:no'
        end
        local file = io.open("elevator.cfg", "w")
        file:write(modemSide.."\n")
        file:write(elevID.."\n")
        file:write(coords.."\n")
        file:write(floors.."\n")
        file:write(bundledConnector)
        file:close()
    end

    iter = string.gmatch(coords, "([^\031]+)") -- create iterator
    x,y,z = tonumber(iter()),tonumber(iter()),tonumber(iter());iter = nil
    modem = peripheral.wrap(modemSide)

    if (bundledConnector=='bundledConnector:yes') then
        redstone = peripheral.wrap(bundleSide)
        rs = redstone
    end

    if z ~= nil then
        print("Starting GPS host")
        if not modem.isOpen(gps.CHANNEL_GPS) then
            print("Opening GPS channel on "..modemSide.." modem")
            modem.open(gps.CHANNEL_GPS)
        end
    else
        y = x; x = nil
    end

    floors = unserialise(floors)
    sortReverse(floors)

    -- Announce self to other floors
    modem.open(os.getComputerID())
    transmit(CHANNEL_ELEVATOR, os.getComputerID(), "ANNOUNCE\030"..y.."\031"..floors[y])

    selected = floors.heights.y

    if #floors.heights == 1 then
        -- This floor only knows about it's self
        term.clear()
        writeToPos(7,4,"No other floors discovered")
        writeToPos(7,6,"Once the elevator program is started")
        writeToPos(7,7,"on other floors, they will appear here.")
    else
        renderFloorList()
    end

    while true do
        eventHandlers:handle(os.pullEvent())
    end
end

assert(pcall(initialise), "An error occured. Please run setup again (pastebin get VYwxa3su setup)")