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

local VERSION = "4.1.0"
local INFERIUM_SERVER = 'inferium.com'
local IDLE_TIME = 2
local WAIT_ITEM_IDLE_TIME = 5
local NETWORK_TIMEOUT = 4
local MIN_INITIAL_FUEL_NEEDED = 16
local ADDITIONAL_FUEL_MARGIN = 100
local MAX_FERTILIZED_ESSENCE = 32
local MIN_FREE_SLOTS_BEFORE_COMPACT = 4
local TIME_TO_START = 3

-- a table with the list of current crops
local localPlan = nil

local previouslyFetchedRemoteConfig = nil

-- UTILS

local function removeFirst(t, x)
  local res = {}
  local removed = false

  for k,v in pairs(t) do
    if not removed and x == v then
      removed = true
    else
      table.insert(res, v)
    end
  end

  return res
end

local function getIndexedCount(t)
  local res = {}

  for k,v in pairs(t) do
    local count = res[v] or 0
    res[v] = count + 1
  end

  return res
end

local function getMinFuelNeeded(config)
  return (ADDITIONAL_FUEL_MARGIN + config.firstCropZ + config.length) * 2
end

local function hasEnoughInitialFuel()
  return turtle.getFuelLevel() >= MIN_INITIAL_FUEL_NEEDED
end

local function retrieveChestFuelOrientation()
  local inventoryFound = false

  for i=1, 4, 1 do
    if turtleUtils.getInventory('front') then
      inventoryFound = true
      break
    end

    turtle.turnRight()
  end

  if not inventoryFound then
    error('chest fuel not found')
  end
end

local function getSeedNameFromCropName(cropName)

  if not cropName then
    return cropName
  end

  return string.gsub(cropName, 'crop', 'seeds')
end

-- Inventory utils
local function getItemSlot(inventory, itemName)
  for slot, item in pairs(inventory.list()) do
    if item and item.name == itemName then
      return slot
    end
  end
end

local function getCountItem(inventory, itemName)
  for _, item in pairs(inventory.list()) do
    if item and item.name == itemName then
      return item.count
    end
  end
end

-- Implementations
local function retrieveHomePositionProcedure()
  print("> retrieving the home position")
  if turtleUtils.getInventory('bottom') then
    retrieveChestFuelOrientation()
    return
  end

  turtle.turnRight()

  if turtle.inspect() then
    turtle.turnRight()
  end

  while true do
    if turtleUtils.getInventory('bottom') then
      turtle.turnLeft()
      return
    end

    if turtle.inspect() then
      break
    else
      turtle.forward()
    end
  end

  turtle.turnLeft()
  turtle.turnLeft()

  while true do
    if turtleUtils.getInventory('bottom') then
      break
    end

    if turtle.inspect() then
      error('Cannot retrieve home position')
    else
      turtle.forward()
    end
  end

  turtle.turnLeft()
end

-- first parameter is config
local function dropAllProcedure(_)
  print('> drop all')
  for i=1, 16, 1 do
    local count = turtle.getItemCount(i)

    if count > 0 then
      turtleUtils.waitForInventory('bottom', IDLE_TIME)

      while turtle.getItemCount(i) and not turtleUtils.dropSlot(i, turtle.dropDown) do
        os.sleep(IDLE_TIME)
      end
    end
  end
end

local function refuelProcedure(config)
  local fuelLevel = turtle.getFuelLevel()
  print('> fuel: ' .. tostring(fuelLevel))

  local minFuelNeeded = getMinFuelNeeded(config)

  if fuelLevel < minFuelNeeded then
    print('> refuel needed (minimum is ' .. minFuelNeeded .. ')')

    local refuelOk, refuelErr = turtleUtils.refuelWithBuffer('bottom', 'front', minFuelNeeded, IDLE_TIME)

    if not refuelOk then
      error('Cannot refuel the turtle: "' .. refuelErr .. '"')
    end

    print('> fuel: ' .. tostring(fuelLevel))
  end
end

local function goToHarvestPoint(config)
  turtle.turnLeft()

  for i=1, config.firstCropZ, 1 do
    turtle.forward()
  end
end

local function goBackToHome(config)
  for i=1, config.firstCropZ, 1 do
    turtle.forward()
  end

  turtle.turnLeft()
end

local function compactIfNeeded()
  if turtleUtils.countFreeSlots() < MIN_FREE_SLOTS_BEFORE_COMPACT then
    turtleUtils.compactInventory()
  end
end

local function applyFertilizedEssenceIfAny()
  if turtleUtils.selectItemByName(inferium.FERTILIZED_ESSENCE) then
    while turtle.placeDown() do end
  end
end

local function harvestDown(index, config)
  if config.fertilizedBoost then
    applyFertilizedEssenceIfAny()
  end

  local cropName = turtleUtils.waitForMatureCrop(turtle.inspectDown, IDLE_TIME)
  local seedName = getSeedNameFromCropName(cropName)

  localPlan[index] = seedName

  if not seedName then
    return false
  end

  if not turtle.digDown() then
    error('turtle cannot harvest crop')
  end

  if not turtleUtils.selectItemByName(seedName) then
    error('turtle cannot find any crop to place')
  end

  if not turtle.placeDown() then
    error('turtle cannot place crop')
  end

  compactIfNeeded()

  return true
end


local function forward()
  local blocked = false

  while not turtle.forward() do
    if not blocked then
      blocked = true
      print('> turtle is blocked')
    end
  end

  if blocked then
    print('turtle is unblocked')
  end
end

local function harvestProcedure(config)
  goToHarvestPoint(config)

  term.write('> harvest on ' .. tostring(config.length) .. ' blocks ')
  local nbHarvested = 0
  for i=1, config.length, 1 do
    if harvestDown(i, config) then
      nbHarvested = nbHarvested + 1
      term.write('.')
    else
      term.write('!')
    end

    if i ~= config.length then
      forward()
    end
  end
  print()

  print('> ' .. tostring(nbHarvested) .. ' harvested crops')

  turtle.turnLeft()
  turtle.turnLeft()

  for i=1, config.length, 1 do
    if i ~= config.length then
      forward()
    end
  end

  goBackToHome(config)
end

local function retrieveLocalPlan(config)
  goToHarvestPoint(config)

  print('> retrieve the local plan')
  localPlan = {}

  for i=1, config.length, 1 do
    local ok, block = turtle.inspectDown()
    local blockName = block and block.name
    localPlan[i] = getSeedNameFromCropName(blockName)

    if i ~= config.length then
      forward()
    end
  end

  turtle.turnLeft()
  turtle.turnLeft()

  for i=1, config.length, 1 do
    if i ~= config.length then
      forward()
    end
  end

  goBackToHome(config)
end

local function fetchRemoteConfig(serverName)
  print('> fetch remote config')
  local message = { type = 'register-and-get-config' }

  local lastErrMessage = nil

  while true do
    local replyMessage, errMessage = net.sendQuery(serverName, message, NETWORK_TIMEOUT)
    if replyMessage and replyMessage.payload then
      previouslyFetchedRemoteConfig = replyMessage.payload
      print('> config fetched')
      local payload = replyMessage.payload
      if not payload then
        error('cannot fetch the remote config')
      end

      if not payload.plan then
        error('no "plan" property found in remote config')
      end

      return payload
    elseif previouslyFetchedRemoteConfig then
      print('> failed to fetch: ' .. tostring(errMessage))
      print('> use the previous recorded remote config instead')

      return previouslyFetchedRemoteConfig
    elseif not replyMessage and errMessage then
      if lastErrMessage ~= errMessage then
        lastErrMessage = errMessage
        print('> failed to fetch: ' .. tostring(errMessage))
      end
    else
      error('unknown error during fetch')
    end

    os.sleep(IDLE_TIME)
  end
end

local function removeSeeds(seeds, config)
  goToHarvestPoint(config)

  local nbOfSeedsToRemove = utils.sizeof(seeds)
  print('> remove ' .. nbOfSeedsToRemove .. ' seed(s)')
  local stateSeeds = seeds -- warning: do not mutate the data (only the ref)

  local nbBlockTraveled = 0
  for i=1, config.length, 1 do
    local ok, block = turtle.inspectDown()
    local blockName = block and block.name

    local found = utils.find(stateSeeds, function(seedName) return seedName == getSeedNameFromCropName(blockName) end)

    if found then
      local digOk = turtle.digDown()

      compactIfNeeded()

      if not digOk then
        error('cannot remove seed')
      end

      stateSeeds = removeFirst(stateSeeds, found)
      nbOfSeedsToRemove = nbOfSeedsToRemove - 1
      if nbOfSeedsToRemove < 1 then
        break
      end
    end

    if i ~= config.length then
      forward()
      nbBlockTraveled = nbBlockTraveled + 1
    end
  end

  turtle.turnLeft()
  turtle.turnLeft()

  for i=1, nbBlockTraveled, 1 do
    forward()
  end

  goBackToHome(config)
  dropAllProcedure(config)
end

local function retrieveSeeds(seeds)
  print('> retrieve seeds from storage')
  local seedRetrieved = false
  local seedsCount = getIndexedCount(seeds)

  local storageInventory = turtleUtils.waitForInventory('bottom', WAIT_ITEM_IDLE_TIME)
  local bufferInventory = turtleUtils.waitForInventory('front', WAIT_ITEM_IDLE_TIME)

  for seedName, count in pairs(seedsCount) do
    local slot = getItemSlot(storageInventory, seedName)

    if slot and count > 0 then
      local inventoryCount = getCountItem(storageInventory, seedName)
      local realCount = math.min(count, inventoryCount)
      local pushOk = storageInventory.pushItems(peripheral.getName(bufferInventory), slot, realCount)

      if not pushOk then
        error('retrieveSeeds error: cannot pushItems from storage to buffer')
      end

      local suckOk = turtle.suck()

      if not suckOk then
        error('retrieveSeeds error: cannot suck items from buffer')
      end

      seedRetrieved = true
    end
  end

  return seedRetrieved
end

-- first parameter is config
local function retrieveFertilizedEssences(_)
  local storageInventory = turtleUtils.waitForInventory('bottom', WAIT_ITEM_IDLE_TIME)
  local bufferInventory = turtleUtils.waitForInventory('front', WAIT_ITEM_IDLE_TIME)

  local slot = getItemSlot(storageInventory, inferium.FERTILIZED_ESSENCE)

  if slot then
    local inventoryCount = getCountItem(storageInventory, inferium.FERTILIZED_ESSENCE)
    local realCount = math.min(MAX_FERTILIZED_ESSENCE, inventoryCount)

    print('> retrieve ' .. tostring(realCount) .. ' fertilized essences from storage')
    local pushOk = storageInventory.pushItems(peripheral.getName(bufferInventory), slot, realCount)

    if not pushOk then
      error('retrieveFertilizedEssences error: cannot pushItems from storage to buffer')
    end

    local suckOk = turtle.suck()

    if not suckOk then
      error('retrieveFertilizedEssences error: cannot suck items from buffer')
    end

    return true
  end

  return false
end

local function replantSeeds(config)
  goToHarvestPoint(config)

  print('> replant seeds')

  local nbBlockTraveled = 0
  for i=1, config.length, 1 do
    local ok, block = turtle.inspectDown()

    if not ok then
      turtleUtils.selectItemBy(turtleUtils.isSeedInSlot)

      turtle.placeDown()

      if turtleUtils.isInventoryEmpty() then
        break
      end
    end

    if i ~= config.length then
      forward()
      nbBlockTraveled = nbBlockTraveled + 1
    end
  end

  turtle.turnLeft()
  turtle.turnLeft()

  for i=1, nbBlockTraveled, 1 do
    forward()
  end

  goBackToHome(config)
end

local function replantProcedure(config)
  local remotePlan = config.plan

  if localPlan == nil then
    retrieveLocalPlan(config)
  end

  if localPlan == nil then
    error('cannot retrieve the local plan')
  end

  local seedsToRemove = utils.shallowDiff(localPlan, remotePlan)
  local seedsToPlant = utils.shallowDiff(remotePlan, localPlan)

  if utils.sizeof(seedsToRemove) > 0 then
    removeSeeds(seedsToRemove, config)
  end

  if utils.sizeof(seedsToPlant) > 0 then
    if retrieveSeeds(seedsToPlant) then
      replantSeeds(config)
    end
  end

  -- reset the local plan (it will be re-updated during the harvest procedure)
  localPlan = {}
end

local function resetTerminal()
  term.clear()
  term.setCursorPos(1, 1)
end

-- Main procedure
local function main()
  net.openRednet()

  print("Starting Trap's inferium harvester v" .. VERSION)

  if not hasEnoughInitialFuel() then
    turtleUtils.refuelAllFromInventory()
  end

  if not hasEnoughInitialFuel() then
    error('Not enough fuel', 0)
  end

  print('Starting harvester in ' .. TIME_TO_START .. ' seconds...')
  os.sleep(TIME_TO_START)

  retrieveHomePositionProcedure()

  local cycleNumber = 1

  while true do
    resetTerminal()
    print('> Starting cycle ' .. tostring(cycleNumber))
    print()

    local remoteConfig = fetchRemoteConfig(inferium.SERVER)

    dropAllProcedure(remoteConfig)
    refuelProcedure(remoteConfig)

    replantProcedure(remoteConfig)

    if remoteConfig.fertilizedBoost then
      print('> fertilized boost enabled')
      retrieveFertilizedEssences(remoteConfig)
    end

    harvestProcedure(remoteConfig)

    cycleNumber = cycleNumber + 1
  end

  net.closeRednet()
end

main()