mining program

dist_param = 256
step = 0


--Movements custom functions

function dig()
    while turtle.detect() do
        turtle.dig()
    end
end


--utility functions

function tryRefuel()
    turtle.select(1)
    fcount = turtle.getItemCount()
    if fcount > 1 then
        turtle.refuel(fcount-1)
    end
end


function homing_or_resume()
    turtle.turnLeft()
    turtle.turnLeft()
    for i=1,step do
        turtle.forward()
    end
end

function unload()
    for i=4,16 do
        turtle.select(i)
        turtle.drop()
    end
end


function diag()
    if turtle.getFuelLevel() < 1000 then
        tryRefuel()
    end
    if turtle.getFuelLevel() < dist_param+20 or turtle.getItemCount(2) < 2 then
        homing_or_resume()
        turtle.select(1)
        turtle.suckUp(turtle.getItemSpace())
        turtle.select(2)
        turtle.suckUp(turtle.getItemSpace())
        tryRefuel()
        unload()
        homing_or_resume()
    end
    if turtle.getItemCount(16) > 0 then
        homing_or_resume()
        unload()
        homing_or_resume()
    end
end


function follow()

    for i=1,4 do
        turtle.turnRight()
        _,id = turtle.inspect()
        if id ~= "No block to inspect" and string.find(id["name"],"ore") ~= nil then
            dig()
            turtle.forward()
            follow()
            turtle.back()
        end
    end

    _,id = turtle.inspectUp()
    if id ~= "No block to inspect" and string.find(id["name"],"ore") ~= nil then
        turtle.digUp()
        turtle.up()
        follow()
        turtle.down()
    end

    _,id = turtle.inspectDown()
    if id ~= "No block to inspect" and string.find(id["name"],"ore") ~= nil then
        turtle.digDown()
        turtle.down()
        follow()
        turtle.up()
    end
end

--Scan functions
function scan()
    for j=1,4 do
        _,id = turtle.inspect()
        if id ~= "No block to inspect" and string.find(id["name"],"ore") ~= nil then
            dig()
            turtle.forward()
            follow()
            turtle.back()
        end
        turtle.turnRight()
    end
end

function scanDown()
    _,id = turtle.inspectDown()
    if id ~= "No block to inspect" and string.find(id["name"],"ore") ~= nil then
        turtle.digDown()
        turtle.down()
        follow()
        turtle.up()
    end
end

function scanUp()
    _,id = turtle.inspectUp()
    if id ~= "No block to inspect" and string.find(id["name"],"ore") ~= nil then
        turtle.digUp()
        turtle.up()
        follow()
        turtle.down()
    end
end


--main function

function mining(dist)
    for i=1,dist do
        step = step+1

        if turtle.detect() then
            dig()
            turtle.forward()
            scanDown()
            scan()
            turtle.digUp()
            turtle.up()
            scan()
            scanUp()
            turtle.down()
        else
            turtle.forward()
            turtle.digUp()
        end

        if not turtle.detectDown() then
            turtle.select(3)
            turtle.placeDown()
        end
        if i%8 == 0 then
            turtle.select(2)
            turtle.back()
            turtle.placeUp()
            turtle.forward()
        end
        diag()
    end
end

mining(dist_param)