local turtleUtils = require('libs/turtle-utils')

local NB_ROWS = 8
local DIRECTION = 'left' -- 'left' | 'right'
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 + NB_ROWS + (MAX_LEVEL * 2 * NB_ROWS)

  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 MOVES = {
  left =  function(strictMode)
    turtle.turnLeft()
    local ok, reason = turtle.forward()

    if strictMode and not ok then
      error('cannot forward because ' .. tostring(reason), 0)
    end

    turtle.turnRight()
    return ok, reason
  end,
  right = function(strictMode)
    turtle.turnRight()
    local ok, reason = turtle.forward()

    if strictMode and not ok then
      error('cannot forward because ' .. tostring(reason), 0)
    end

    turtle.turnLeft()
    return ok, reason
  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 selectItem = function(itemName)
  for i=1, 16, 1 do
    local details = turtle.getItemDetail(i)
    if details and details.name == itemName 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 = selectItem(blockName)

  if not selected then
    return 'error'
  end

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

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

local placeDownItem = function(itemName)
  if selectItem(itemName) then
    turtle.placeDown()
  else
    placeDownFillBlock()
  end
end

-- Main state and stateful methods
local function getInitialState()
  return {
    firstPickedItem = nil,
    y = 1,
    initialLevel = 0,
    newLevel = 0,
    errorLevel = nil
  }
end

-- local state = getInitialState()

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

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

local function tryToSelectEmptySlot()
  if not turtleUtils.selectFirstEmptySlot() then
    turtleUtils.compactInventory()
    if not turtleUtils.selectFirstEmptySlot() then
      error('Fatal error: turtle inventory is full', 0)
    end
  end
end

-- 1. down procedure
local downProcedure = function(state)
  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

    if not state.firstPickedItem then
      tryToSelectEmptySlot()
      digAndGoDown(state)

      local item = turtle.getItemDetail(turtle.getSelectedSlot())
      -- consider FILL_BLOCK if no block was picked
      state.firstPickedItem = (item and item.name) or FILL_BLOCK
    else
      digAndGoDown(state)
    end

  end
end

-- 2. up procedure
local upProcedure = function(state)
  local firstY = getInitialState().y

  while state.y ~= firstY do
    goUp(state)

    if state.y == firstY and state.firstPickedItem then
      placeDownItem(state.firstPickedItem)
    else
      placeDownFillBlock()
    end
  end
end

-- 3. print report
local printReport = function(state)
  local baseReport = 'Level ' .. tostring(state.initialLevel) .. ' -> ' .. state.newLevel

  if state.errorLevel then
    print (baseReport .. ' (tier ' .. getTierFromLevel(state.errorLevel) .. ')')
  else
    print (baseReport)
  end
end

local upgradeProcedure = function()
  turtleUtils.compactInventory()

  local state = getInitialState()

  downProcedure(state)
  upProcedure(state)
  printReport(state)

  return state
end

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

  for i=1, NB_ROWS, 1 do
    upgradeProcedure()

    if i ~= NB_ROWS then
      MOVES[DIRECTION](true)
    else
      MOVES[DIRECTION](false) -- do not throw if cannot move forward
    end
  end

end

main()