Computercraft Wall

-- usage: "Wall <X> <Y> <Direction>"
-- <X> = number of blocks over
-- <Y> = number of block up
-- <Direction> = direction the wall will be built
--      accepts "Left" or "Right"
-- The turtle will look at slot 1 to find what block it has to work with.  It will look to see if there are any successive blocks
-- with the same block type.  All 16 slots can be used as long as the block type is the same.  If a different type of block is in
-- slot 4, for example, only slots 1, 2, and 3 will be used.

-- See this program in action at https://youtu.be/fLfqDiI0tsY

local variables = {...}

x = tonumber(variables[1])
y = tonumber(variables[2])

success = null
data = {}
data.name = null

block = {}
block2 = {}
slots = 0

locationX = 0
locationY = 0

direction = "left"
directionY = "up"

function printUsage()
    print("Wall program usage:\nWall <X> <Y> <Direction>\n\t<X> = number of blocks over\n\t<Y> = number of blocks up\n\t<Direction> = direction the wall will be build\n\t\taccepts 'Left' or 'Right'")
end

function start()
    if tonumber(variables[1]) == null then
        printUsage()
        return false
    end
    if tonumber(variables[2]) == null then
        printUsage()
        return false
    end
    if variables[3] ~= null then
        if string.lower(variables[3]) == "left" then
            print("direction set Left")
            direction = "left"
        elseif string.lower(variables[3]) == "right" then
            print("direction set Right")
            direction = "right"
        else
            printUsage()
            return false
        end
    end
    turtle.select(1)
    if turtle.getItemDetail() == null then
        print ("place some blocks in the turtle")
        return false
    end
    slots = 1
    block = turtle.getItemDetail()
    for i=2, 16 do
        turtle.select(i)
        if turtle.getItemDetail() == null then
            break
        end
        block2 = turtle.getItemDetail()
        if block.name == block2.name then
            slots = i
        else
            break
        end
    end
    turtle.select(1)
    print("Turtle will build a wall " .. x .. " by " .. y .. " blocks")
end

function tryForward()
    while turtle.forward() ~= true do
        success, data = turtle.inspect()
        if data.name == "minecraft:bedrock" then
            return false
        elseif success then
            turtle.dig()
        elseif turtle.attack() then
            turtle.suck()
        else
            sleep(0.5)
        end
    end
    return true
end

function tryDown()
    while turtle.down() ~= true do
        success, data = turtle.inspectDown()
        if data.name == "minecraft:bedrock" then
            return false
        elseif success then
            turtle.digDown()
        elseif turtle.attackDown() then
            turtle.suckDown()
        else
            sleep(0.5)
        end
    end
    locationY = locationY - 1
    return true
end

function tryUp()
    while turtle.up() ~= true do
        success, data = turtle.inspectUp()
        if data.name == "minecraft:bedrock" then
            return false
        elseif success then
            turtle.digUp()
        elseif turtle.attackUp() then
            turtle.suckUp()
        else
            sleep(0.5)
        end
    end
    locationY = locationY + 1
    return true
end

function slideLeft()
    turtle.turnLeft()
    tryForward()
    turtle.turnRight()
    tryPlace()
end

function slideRight()
    turtle.turnRight()
    tryForward()
    turtle.turnLeft()
    tryPlace()
end

function digUp()
    while turtle.detectUp() == true do
        turtle.digUp()
        sleep(0.5)
    end
end

function dig()
    while turtle.detect == true do
        turtle.dig()
        sleep(0.5)
    end
end

function tryPlace()
    invCheck()
    success, data = turtle.inspect()
    if data.name ~= block.name then
        while turtle.dig() == true do
            sleep(0.5)
        end
        turtle.place()
    end
end

function invCheck()
    if turtle.getItemDetail() ~= null then
        block2 = turtle.getItemDetail()
    else
        block2.name = "empty"
    end
    if block.name ~= block2.name then
        if turtle.getSelectedSlot() < slots then
            turtle.select(turtle.getSelectedSlot() + 1)
        else
            local locationX2 = locationX
            local locationY2 = locationY
            locationX = locationX + 1
            goHome()
            print("Out of items.  Please replace and press Enter")
            turtle.select(1)
            if turtle.getItemDetail() ~= null then
                block2 = turtle.getItemDetail()
            else
                block2.name = "blank"
            end
            while block2.name ~= block.name do
                block2 = turtle.getItemDetail()
                local event, key = os.pullEvent("key")
                if key == 28 then
                    break
                end
            end
            goBack(locationX2,locationY2)
            locationX = locationX - 1
        end
    end
end

function nextRow()
    if locationX < x then
        if direction == "left" then
            fuelCheck()
            slideLeft()
        elseif direction == "right" then
            fuelCheck()
            slideRight()
        end
        locationX = locationX + 1
    end
end

function buildRow()
    if directionY=="up" then
        while locationY<y-1 do
            fuelCheck()
            tryUp()
            tryPlace()
        end
        directionY = "down"
    elseif directionY=="down" then
        while locationY>0 do
            fuelCheck()
            tryDown()
            tryPlace()
        end
        directionY = "up"
    end
end

function goHome()
    if direction == "left" then
        turtle.turnRight()
    elseif direction == "right" then
        turtle.turnLeft()
    end
    for i=1,locationX-1 do
        tryForward()
    end
    if direction == "right" then
        turtle.turnRight()
    elseif direction == "left" then
        turtle.turnLeft()
    end
    for i=1,locationY do
        tryDown()
    end
end

function goBack(X2,Y2)
    if direction == "left" then
        turtle.turnLeft()
    elseif direction == "right" then
        turtle.turnRight()
    end
    for i=1,X2 do
        tryForward()
    end
    if direction == "left" then
        turtle.turnRight()
    elseif direction == "right" then
        turtle.turnLeft()
    end
    for i=1,Y2 do
        tryUp()
    end
end

function refuel()
    print("Put fuel in any free slot and press any key")
    local suc = false
    while true do
        local event, key = os.pullEvent("key")
        if key ~= null then
            break
        end
    end
    local curSlot = turtle.getSelectedSlot()
    for i=1,16 do
        turtle.select(i)
        if turtle.refuel() == true then
            suc = true
        end
    end
    turtle.select(curSlot)
    if suc == true then
        return true
    else
        return false
    end
end

function fuelCheck()
    if turtle.getFuelLevel() <= locationX + locationY +2 then
        local locationX2 = locationX
        local locationY2 = locationY
        locationX = locationX + 1
        goHome()
        while refuel() == false do
        end
        goBack(locationX2,locationY2)
        locationX = locationX - 1
    end
    return true
end

--Program Start
if start() == false then
    return
end
while locationX < x do
    tryPlace()
    buildRow()
    if locationX < x-1 then
        nextRow()
    else
        locationX = locationX + 1
    end
end
goHome()