placeAndBreak.lua

local blocksToBreak = {
  "essentialcraft:oreDrops", "GalacticraftCore:tile.gcBlockCore",
  "appliedenergistics2:tile.OreQuartzCharged", "denseores:block1"
}
local sides = require("sides")
local inputSide = sides.bottom
local outputSide = sides.top

local component = require("component")

if not component.isAvailable("robot") then
  io.stderr:write("can only run on robots")
  return
end

local r = component.robot
local invcon = component.inventory_controller

-- return true if in front of the robot is not air
local function somethingInTheWay()
  local _, what = r.detect(sides.front)
  return (what ~= "air")
end

-- return true if given item name is one to be placed and broken
local function isBlockToBreak(itemName)
  for _, name in ipairs(blocksToBreak) do
    if itemName == name then
      return true
    end
  end
  return false
end

-- search the input inventory for a block to break, put it into slot 2 and return true,
-- or return false if no block found
local function retrieveBlock()
  r.select(2)
  local myStack2 = invcon.getStackInInternalSlot(2)
  if myStack2 ~= nil then
    if isBlockToBreak(myStack2["name"]) then
      -- print("already have block")
      return true
    else
      print("Unknown item in slot 2")
      return false
    end
  end
  
  -- now slot 2 is empty and selected
  
  local inputSize = invcon.getInventorySize(inputSide)
  
  if inputSize == nil then
    print("No inventory below me")
    return false
  end
  
  local slot = 1
  local stack = nil
  while slot <= inputSize do
    stack = invcon.getStackInSlot(inputSide, slot)
    
    if stack ~= nil and isBlockToBreak(stack["name"]) then
      break
    else
      slot = slot + 1
    end
  end
  
  if stack == nil then
    print("None of the inventory slots have a block to break")
    return false
  end
  
  print("I found a " .. stack["name"] .. " in slot " .. slot)
  
  invcon.suckFromSlot(inputSide, slot)
  
  myStack2 = invcon.getStackInInternalSlot(2)
  if not isBlockToBreak(myStack2["name"]) then
    print("Bait and switch! I thought I got a " .. stack["name"] .. " but instead I got a " .. myStack2["name"])
    -- just keep it, it'll get deposited to output on next run
    return false
  else
    print("I obtained the " .. myStack2["name"])
    return true
  end
end

-- replenish pickaxe from input inventory
local function replenishPickaxe()
  local toolslot, _, _ = r.durability()
  if toolslot ~= nil then
    -- print("already have pickaxe")
    return true
  end
  
  print("I need a diamond pickaxe")
  
  if invcon.getInventorySize(inputSide) == nil then
    print("No inventory below me")
    return false
  end
  
  local slot = 1
  while true do
    local stack = invcon.getStackInSlot(inputSide, slot)
    if stack == nil then
      print("None of the inventory slots have a diamond pickaxe")
      return false
    end
    
    if stack["name"] == "minecraft:diamond_pickaxe" then
      break
    else
      slot = slot + 1
    end
  end
  
  print("I found a diamond pickaxe in slot " .. slot)
  
  r.select(1)
  invcon.suckFromSlot(inputSide, slot)
  
  local myStack1 = invcon.getStackInInternalSlot(1)
  if myStack1["name"] ~= "minecraft:diamond_pickaxe" then
    print("Bait and switch! I thought I got a pickaxe but instead I got a " .. myStack1["name"])
    -- drop it
    r.drop(sides.front)
    return false
  end
  
  -- now we have a diamond pickaxe in slot 1, just need to equip it
  invcon.equip()
  
  print("I equipped the diamond pickaxe")
  return true
end

-- checks slot 2 for non-block items; if any, deposits them into the output side
-- returns true if slot 2 is already empty or has been deposited, or it's a breakable block
-- returns false for error such as output inventory full or missing
local function depositObtainedItems()
  r.select(2)
  
  local myStack2 = invcon.getStackInInternalSlot(2)
  
  if myStack2 == nil or isBlockToBreak(myStack2["name"]) then
    -- nothing to deposit
    return true
  end
  
  print("Depositing items: " .. myStack2["size"] .. " " .. myStack2["name"])
  
  local outputSize, outputErr = invcon.getInventorySize(outputSide)
  if outputSize == nil then
    print("Output error: " .. outputErr)
    return false
  end
  
  local slot = 1
  while true do
    local stack = invcon.getStackInSlot(outputSide, slot)
    
    if stack == nil or stack["name"] == myStack2["name"] then
      local dropped = invcon.dropIntoSlot(outputSide, slot)
      -- it is possible that the items aren't actually the same (same name, different metadata)
      -- so in that case drop returns false, we will not return and instead will keep looping
      if dropped then return true end
    end
    
    slot = slot + 1
    if slot > outputSize then
      print("No free output slots")
      return false
    end
  end
end

-- ensure we have a pickaxe, obtain a block, place it, break it, pick up the pieces, deposit into the output side
-- if all goes well, return true which means immediately do it again
-- if there's a problem, return false which means maybe wait a bit before retrying
local function placeAndBreak()
  -- ensure we have a pickaxe
  local hasPickaxe = replenishPickaxe()
  if not hasPickaxe then return false end
  
  -- ensure slot 2 is empty or already has a breakable block in it
  local preDepositedItems = depositObtainedItems()
  if not preDepositedItems then return false end
  
  -- retrieve a breakable block
  local hasBlock = retrieveBlock()
  if not hasBlock then return false end
  
  -- ensure there is nothing in front of me
  if somethingInTheWay() then
    print("There is something in the way, can't place the block")
    return false
  end
  
  -- place the block
  r.select(2)
  local placedBlock = r.place(sides.front)
  if not placedBlock then
    print("Couldn't place the block")
    return false
  end
  
  -- now mine the block in front of me (it obtains the mined items)
  local minedBlock = r.swing(sides.front)
  if not minedBlock then
    print("Couldn't mine the block")
    return false
  end
  
  local depositedItems = depositObtainedItems()
  if not depositedItems then
    print("Couldn't deposit the mined items")
    return false
  end
  
  -- all done!
  return true
end

while true do
  local success = placeAndBreak()
  if success then
    print("Success, iterating again")
  else
    print("Sleeping 3 seconds and retrying")
    os.sleep(3)
  end
end