local robot = require("robot");
local component = require("component")
local inv = component.inventory_controller
local geo = component.geolyzer

local branchLength = 32
local turnRight = true

local toolSlotCount = 2
local fortune = true

local lastSlot = robot.inventorySize() - toolSlotCount
if fortune then
  lastSlot = lastSlot - 1
end
local fortuneSlot = robot.inventorySize() - toolSlotCount
local firstToolSlot = robot.inventorySize() - (toolSlotCount - 1)

local validTools = {
  'minecraft:stone_pickaxe',
  'minecraft:iron_pickaxe',
  'minecraft:diamond_pickaxe'
}

local oreList = {
  'minecraft:dirt',
  'minecraft:stone',
}

local ores = {}
for i, ore in ipairs(oreList) do
  ores[ore] = true
end

local bottom = 0
local top = 1
local back = 2
local front = 3
local right = 4
local left = 5

function fortuneSwap()
  if fortune then
    robot.select(fortuneSlot)
    inv.equip()
    robot.select(1)
  end
end

function isOre(block)
  return ores[block.name] or false
end

function mineOre(inOrePos)
  for i = 0, 5, 1 do
    local block = geo.analyze(i)
    local oreInDir = isOre(block)
    if oreInDir or inOrePos then
      local isDiamond = block.name == 'minecraft:stone'
      if isDiamond then
        fortuneSwap()
      end
      mineInDir(i)
      if isDiamond then
        fortuneSwap()
      end
      mineOre(oreInDir)
      undoMineInDir(i)
    end
  end
end

function mineInDir(dir)
  if dir == 0 then
    swingDownIfTool()
    robot.down()
  elseif dir == 1 then
    swingUpIfTool()
    robot.up()
  elseif dir == 2 then
    robot.turnAround()
    swingIfTool()
    robot.forward()
  elseif dir == 3 then
    swingIfTool()
    robot.forward()
  elseif dir == 4 then
    robot.turnRight()
    swingIfTool()
    robot.forward()
  elseif dir == 5 then
    robot.turnLeft()
    swingIfTool()
    robot.forward()
  else
    error('ERROR: invalid dir')
  end
end

function undoMineInDir(dir)
  if dir == 0 then
    robot.up()
  elseif dir == 1 then
    robot.down()
  elseif dir == 2 then
    robot.turnAround()
    robot.forward()
  elseif dir == 3 then
    robot.back()
  elseif dir == 4 then
    robot.back()
    robot.turnLeft()
  elseif dir == 5 then
    robot.back()
    robot.turnRight()
  else
    error('ERROR: invalid dir')
  end
end

function isValidTool(stack)
  return includes(validTools, stack.name)
end

function turnInBranchDir()
  if turnRight then
    robot.turnRight()
  else
    robot.turnLeft()
  end
end

function swingIfTool()
  if robot.durability() == nil then
    grabTool()
  end
  robot.swing()
  raiseIfInventoryFull()
end

function swingUpIfTool()
  if robot.durability() == nil then
    grabTool()
  end
  robot.swingUp()
  raiseIfInventoryFull()
end

function swingDownIfTool()
  if robot.durability() == nil then
    grabTool()
  end
  robot.swingDown()
  raiseIfInventoryFull()
end

function raiseIfInventoryFull()
  if inv.getStackInInternalSlot(lastSlot) ~= nil then
    error('ERROR: inventory full')
  end
end

function includes(arr, item)
  for i, v in ipairs(arr) do
    if v == item then
      return true
    end
  end
  return false
end

function grabTool()
  local toolFound = false
  for i = robot.inventorySize(), firstToolSlot, -1 do
    local stack = inv.getStackInInternalSlot(i)
    if stack ~= nil and isValidTool(stack) then
      robot.select(i)
      inv.equip()
      robot.select(1)
      toolFound = true
    end
  end
  if not toolFound then
    error('ERROR: no tool')
  end
end

function mineForward()
  swingIfTool()
  robot.forward()
  placeDownIfAir()
  mineOre()
  swingUpIfTool()
  robot.up()
  mineOre()
  robot.down()
end

function placeDownIfAir()
  if not robot.detectDown() then
    robot.placeDown()
  end
  if not robot.detectDown() then
    error("ERROR: place failed!")
  end
end

function branch()
  turnInBranchDir()
  for i = 1, branchLength, 1 do
    mineForward()
  end
  robot.turnAround()
  for i = 1, branchLength, 1 do
    robot.forward()
  end
  turnInBranchDir()
end

while true do
  for i = 1, 4, 1 do
    mineForward()
  end
  branch()
end