local FILL_BLOCK = 'minecraft:cobblestone'
local LEVEL_PER_TIER = 12

local formatBlockName = function(tierName)
  return "mysticalagriculture:" .. tierName .. "_growth_accelerator"
end

local BLOCKS_PER_TIER = {
  formatBlockName('inferium'),
  formatBlockName('prudentium'),
  formatBlockName('tertium'),
  formatBlockName('imperium'),
  formatBlockName('supremium')
}

local MAX_LEVEL = LEVEL_PER_TIER * #BLOCKS_PER_TIER

local countItems = function(itemName)
  local total = 0

  for i=1,16,1 do
    local details = turtle.getItemDetail(i)
    if details and details.name == itemName then
      total = total + details.count
    end
  end

  return total
end

local assertEnoughFillBlocks = function()
  local count = countItems(FILL_BLOCK)

  if count < MAX_LEVEL then
    error('Not enough fill blocks, please provide at least ' .. MAX_LEVEL .. ' of ' .. FILL_BLOCK)
  end
end

local assertEnoughFuel = function()
  local minFuel = 10 + (MAX_LEVEL * 2)

  if turtle.getFuelLevel() < minFuel then
    error('Not enough fuel')
  end
end

local refuel = function()
  for i=1, 16, 1 do
    local count = turtle.getItemCount(i)
    if count > 0 then
      turtle.select(i)
      turtle.refuel()
    end
  end
end

local getTierFromLevel = function(level)
  return math.floor((level - 1) / LEVEL_PER_TIER) + 1
end

local getBlockNameFromLevel = function(level)
  local tier = getTierFromLevel(level)
  return BLOCKS_PER_TIER[tier]
end

local inspectBlockName = function()
  local ok, block = turtle.inspect()

  if not ok then
    return nil
  end

  return block and block.name
end

local selectBlock = function(blockName)
  for i=1, 16, 1 do
    local details = turtle.getItemDetail(i)
    if details and details.name == blockName then
      turtle.select(i)
      return true
    end
  end

  return false
end

local replaceBlockAt = function(y)
  local blockName = getBlockNameFromLevel(y);

  if inspectBlockName() == blockName then
    return false
  end

  local selected = selectBlock(blockName)

  if not selected then
    return 'error'
  end

  turtle.dig()
  turtle.place()
  return true
end

local placeDownFillBlock = function()
  selectBlock(FILL_BLOCK)
  turtle.placeDown()
end

-- Main state and stateful methods
local state = {
  y = 1,
  initialLevel = 0,
  newLevel = 0,
  errorLevel = nil
}

local digAndGoDown = function()
  turtle.digDown()
  turtle.down()
  state.y = state.y + 1
end

local goUp = function()
  turtle.up()
  state.y = state.y - 1
end

-- 1. down procedure
local downProcedure = function()
  while state.y < 60 do
    local replaced = replaceBlockAt(state.y)

    if replaced == false then
      state.initialLevel = state.y
      state.newLevel = state.initialLevel
    end

    if replaced == true then
      state.newLevel = state.y
    end

    if replaced == 'error' then
      state.errorLevel = state.y
      break
    end

    digAndGoDown()
  end
end

-- 2. up procedure
local upProcedure = function()
  while state.y ~= 1 do
    goUp()
    placeDownFillBlock()
  end
end

-- 3. print report
local printReport = function()
  local initialLevel = state.initialLevel
  if initialLevel == nil then
    initialLevel = 'nil'
  end
  print('Initial Level: ' .. initialLevel)
  print('New Level: ' .. state.newLevel)

  if state.errorLevel then
    local tier = getTierFromLevel(state.errorLevel)

    print('Tier ' .. tier .. ' needed for next upgrade') 
  end
end

-- Main function
local main = function()
  assertEnoughFillBlocks()
  refuel()
  assertEnoughFuel()

  downProcedure()
  upProcedure()
  printReport()
end

main()