ValuableFinderv1

depth = 0
descending = true

function fuel()
    if turtle.getFuelLevel() <= 10 then
        turtle.select(16)
        turtle.refuel()
    end
end

function isValuable()
    local junkTable = {"minecraft:stone", "minecraft:dirt", "minecraft:gravel", "minecraft:sand", "minecraft:torch"}
    local valuable = true

    local isBlock, blockData = turtle.inspect()
        if isBlock == true then
            print("There's something here. Block data:")
            print(blockData.name)
            print(blockData.metadata)
            for k, v in ipairs(junkTable) do
                if blockData.name == v then
                    print("This is junk.")
                    valuable = false
                    break
                end
            end
        else
            print("There isn't anything here.")
            valuable = false
        end
    if valuable then
        print("There's something valuable here!")
        return true

    else
        print("Nothing interesting here. Moving on")
        return false
    end
end

function checkSides()
    for i = 0, 3, 1 do
        if isValuable() then
            turtle.dig()
        end
        turtle.turnRight()
    end
end

function isBottomEmpty()
    local isBlock, blockData = turtle.inspect()
    if isBlock then
        return true
    else
        return false
    end
end

function isBottomBedrock()
    local isBlock, blockData = turtle.inspectDown()
    if isBlock then
        if blockData.name == "minecraft:bedrock" then
            print("We've hit bedrock!")
            return true
        else
            return false
        end
    else
        return false
    end
end


print("Let's go!")


while descending do
    fuel()
    checkSides()
    if isBottomBedrock() then
        descending = false
        break
    end
    turtle.digDown()
    turtle.down()
    depth = depth + 1
end

print("Let's go back up...")

while depth ~= 0 do
    fuel()
    if turtle.up() then
        depth = depth - 1
    else
        print("Obstruction detected...")
        turtle.digUp()
    end
end

print("Done!")