Auto Miner V2.0

-- West = Negative x
-- Top = Positive y
-- North = Negative z

local x,y,z = 0,0,0 --Relative to First position
local Orien = 0 --0:Forward; 1:Right; 2:Back; 3:Left
local Heading = {x=0,y=0,z=0}
local Query
local IsFull = false

function MoveUp(amount)
    if (amount<0) then amount=amount*-1 end
    if (amount==0) then return end

    for i=1,amount,1 do
        turtle.digUp()
        if (turtle.up()) then
            y=y+1
        end
    end
end
function MoveDown(amount)
    if (amount<0) then amount=amount*-1 end
    if (amount==0) then return end

    for i=1,amount,1 do
        turtle.digDown()
        if (turtle.down()) then
            y=y-1
        end
    end
end

function MoveForward(amount)
    if (amount<0) then amount=amount*-1 end
    if (amount==0) then return end

    for i=1,amount,1 do
        turtle.dig()
        if (turtle.forward()) then
            if (Orien==0)then
                z=z-1
            elseif (Orien==1)then
                x=x+1
            elseif (Orien==2)then
                z=z+1
            elseif (Orien==3)then
                x=x-1
            end
        end
    end
end

function SetFacing(direction)
    while(true) do
        if (direction==Orien) then
            break
        end

        if (turtle.turnRight()) then
            Orien = Orien+1
            if (Orien>3) then Orien=0 end
        end
    end
end

function Movement()
    --X
    if (x>Heading.x) then
        SetFacing(3)
    elseif (x<Heading.x) then
        SetFacing(1)
    end
    MoveForward(Heading.x - x)

    --Y
    if (y>Heading.y) then
        MoveUp(Heading.y - y)
    elseif (y<Heading.y) then
        MoveDown(Heading.y - y)
    end

    --Z
    if (z>Heading.z) then
        SetFacing(0)
    elseif (z<Heading.z) then
        SetFacing(2)
    end
    MoveForward(Heading.z - z)
end

function Search()
    turtle.select(2)
    turtle.equipRight() --Equip scanner
    local Scanner = peripheral.wrap("right")
    local scan = Scanner.scan(16)
    if (scan ~= nil) then
        for i, data in ipairs(scan) do
            if (string.match(data.name, Query)) then
                Heading.x = data.x+x
                Heading.y = data.y+y
                Heading.z = data.z+z
                break
            end
        end
    end
    turtle.select(2)
    turtle.equipRight(2) --UnEquip scanner

    turtle.select(1) --Equip bucket
end

function Refuel()
    turtle.select(1) --Equip bucket

    local success, data = turtle.inspect()
    if (success and data.name=="minecraft:lava") then
        turtle.place()
    end

    success, data = turtle.inspectUp()
    if (success and data.name=="minecraft:lava") then
        turtle.placeUp()
    end

    success, data = turtle.inspectDown()
    if (success and data.name=="minecraft:lava") then
        turtle.placeDown()
    end
end

function Inventory()
    --1 and 2 are the bucket and the scanner, so DON'T drop them
    IsFull = true
    for i=3,16,1 do
        local data = turtle.getItemDetail(i)
        if (string.match(data.name, Query)~=false) then
            turtle.select(i)
            turtle.drop()
            IsFull = false
        end
    end
    turtle.select(1) --Equip bucket
end

function GoHome()
    local FuelNeeded = math.floor((x+y+z)*2.5) -- Imagine is a straight line and then think it has to dig all the way
    if (turtle.getFuelLevel()<=FuelNeeded or ISFull==true) then
        Heading.x=0
        Heading.y=0
        Heading.z=0
        Movement()
        return true
    end

    return false
end

-- Main --
term.setTextColor(colors.green)
term.write("Instructions: Place a bucket in the first slot, then a geo scanner in the seccond, then equip a pickaxe on the right side and a chunk loader on the left.")

term.setTextColor(colors.cyan)
term.write("Search for: ")
Query = read()
while(true) do
    term.clear()
    term.setCursorPos(1,1)
    term.write(Query .. " at: " .. Heading.x .. " " .. Heading.y .. " " .. Heading.z)

    if (GoHome()==false) then
        Search()
        Movement()
        Refuel()
        Inventory()
    else
        term.clear()
        term.setCursorPos(1,1)
        term.write("Heading home.")
        break
    end
end