-- Minecraft - Turtle - Drill down to bedrock and return to surface
local protocol = "ZigMiningTurtles"

-- Check block in front of us against black list of blocks we don't want (dirt, stone)
function blockValuable(name)
  if name == "minecraft:dirt" then return false
  elseif name == "minecraft:stone" then return false
  elseif name == "minecraft:cobblestone" then return false
  elseif name == "minecraft:gravel" then return false
  elseif name == "minecraft:sand" then return false
  elseif name == "chisel:diorite" then return false
  elseif name == "chisel:andesite" then return false
  elseif name == "chisel:limestone" then return false
  elseif name == "chisel:granite" then return false
  end
  return true
end

-- mine block in front of us if it is valuable
function mineValuableBlock()
  local success, data = turtle.inspect()
  if success then
    if blockValuable(data.name) then
      turtle.dig()
    end
  end
end

-- Digs down until we reach bed rock
function drillDown()
  local depth = 0
  turtle.digDown()

  while turtle.down() do
    depth = depth + 1
    mineValuableBlock()
    turtle.turnRight()
    mineValuableBlock()
    turtle.turnRight()
    mineValuableBlock()
    turtle.turnRight()
    mineValuableBlock()
    turtle.turnRight() -- wasted movement (already checked ore), but this keeps our orientation the same

    turtle.digDown()
  end
  print("drilled down " .. depth .. " blocks")

  -- Sends the turtle back to (1 block below) the start
  for index = 2,depth do
    turtle.up()
  end --for

  -- place "cap" on top of drilled hole using slot
  turtle.select(1)
  turtle.placeDown()

  -- go to original position (above ground level)
  turtle.up()

end

-- Assumes there is an Ender chest in slot 2, which we place in front of us and then dump all of our inventory in it
-- picking up the chest after we are done
function dumpInventoryInChest()
  print("Dumping inventory into Ender Chest (slot 2)")
  turtle.select(2)
  turtle.place() -- assumes the block in front of us is ok
  turtle.select(1)
  turtle.drop()
  for slot=3, 16 do
    turtle.select(slot)
    turtle.drop()
  end
  turtle.select(2)
  turtle.dig()
end

-- Move forward 5 blocks, which efficiently covers a space in drill holes without checking any blocks twice
function moveToNextDrillLocation()
  print("Moving to next drill location (5 blocks forward)")
  -- try to move forward, there may be something in front of us however, so dig it out
  local i = 0
  while i<5 do
    turtle.dig()
    local success = turtle.forward()
    if success then
      i = i + 1
      turtle.digUp() -- make high enough for players to pass
    else
      turtle.dig()
    end
  end
end

function controlServerOnline()
  rednet.open("right")
  local serverID = rednet.lookup(protocol)
  if serverID then
    local msg = serverID, os.getComputerLabel() .. " reporting in at " .. textutils.formatTime(os.time(), false) .. " FL: " .. turtle.getFuelLevel()
    rednet.send(msg, protocol)
    print(msg)
    return true
  else
    print("Failed to find Turtle Mining Server, shutting down.")
    return false
  end
end

-- Main script
while true do
  if not controlServerOnline() then
    return
  end

  if turtle.getFuelLevel() < 2800 then
    print("Fuel level must be at least 2800 (drill down 65 blocks and return)")
    return
  end
  print("Drilling down to bedrock.. ")
  drillDown()
  dumpInventoryInChest()
  moveToNextDrillLocation()
end