depth = 150
valuable = {"minecraft:torch", "minecraft:diamond", "minecraft:iron_ore", "minecraft:lapis_lazuli", "minecraft:coal", "minecraft:gold_ore", "minecraft:redstone"}
garbage_interval = 30
torch_interval = 16
torch_slot = 2

function emptyIntoChest()
    for i = 1, 16 do
        turtle.select(i)
        turtle.drop()
    end
end

function deleteGarbage()
    for i = 1,16 do
        turtle.select(i)
        data = turtle.getItemDetail()
        if data ~= nil then
            name = data["name"]
            keep = true

            if keep == false then
                turtle.dropDown()
                print("dropping item" .. name)
            end
        end
    end
end

function placeTorch()
    turtle.down()
    turtle.select(torch_slot)
    turtle.back()
    turtle.back()
    turtle.place()
    turtle.up()
    turtle.forward()
    turtle.forward()
end



if turtle.getFuelLevel() < 350 then
    turtle.select(1)
    turtle.refuel()
end

if turtle.getFuelLevel() < 350 then
    print("refuel not succesful")
    error()
end

function checkTorches()
    turtle.select(torch_slot)
    torch_count = turtle.getItemCount()
    if torch_count < depth/torch_interval then
        print("not enough torches")
    end
end


for a=1,depth do

    turtle.dig()
    turtle.forward()
    turtle.digUp()
    turtle.digDown()

    if a%garbage_interval == 0 then
        deleteGarbage()
    end

    if a%torch_interval == 0 then
        placeTorch()
    end

end

for a=1, depth do
    turtle.back()
end

turtle.turnLeft()
turtle.turnLeft()

if turtle.detect() then
    -- chest exists
    print("chest found")
    emptyIntoChest()
end

print(tostring(turtle.getFuelLevel()))