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

local VERSION = "2.2.0"
local INFERIUM_SERVER = 'inferium.com'
local IDLE_TIME = 2
local WAIT_ITEM_IDLE_TIME = 5
local NETWORK_TIMEOUT = 4
local MIN_FUEL_NEEDED = (100 + config.firstCropZ + config.length) * 2
local MIN_FREE_SLOTS_BEFORE_COMPACT = 4

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

local previouslyFetchedRemotePlan = 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 hasEnoughFuel()
  return turtle.getFuelLevel() >= MIN_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

local function isSeed(item)
  local tags = item and item.tags or {}
  return tags['forge:seeds'] or tags['mysticalagriculture:seeds'] or false
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

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

local function refuelProcedure()
  print('> refuel')
  local refuelOk, refuelErr = turtleUtils.refuelWithBuffer('bottom', 'front', MIN_FUEL_NEEDED, IDLE_TIME)

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

local function goToHarvestPoint()
  turtle.turnLeft()

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

local function goBackToHome()
  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 harvestDown(index)
  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()
  if not turtle.forward() then
    error('turtle is blocked')
  end
end

local function harvestProcedure()
  print('> harvest')

  for i=1, config.length, 1 do
    harvestDown(i)

    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
end

local function retrieveLocalPlan()
  goToHarvestPoint()

  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()
end

local function fetchRemotePlan()
  print('> fetch remote plan')
  local message = { type = 'getplan' }

  while true do
    local replyMessage, _ = net.sendQuery(INFERIUM_SERVER, message, NETWORK_TIMEOUT)
    print('> fetched')

    if replyMessage and replyMessage.payload then
      previouslyFetchedRemotePlan = replyMessage.payload
      return replyMessage.payload
    elseif previouslyFetchedRemotePlan then
      print('> failed to fetch remote plan, use the previous one instead')
      return previouslyFetchedRemotePlan
    end

    os.sleep(IDLE_TIME)
  end
end

local function removeSeeds(seeds)
  goToHarvestPoint()

  print('> remove old seeds')
  local stateSeeds = seeds -- warning: do not mutate the data (only the ref)

  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)
    end

    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()
  dropAllProcedure()
end

local function retrieveSeeds(seeds)
  print('> retrieve seeds from inventory')
  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

local function replantSeeds()
  goToHarvestPoint()

  print('> replant seeds')

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

    if not ok then
      turtleUtils.selectItemBy(function(slot)
        local item = turtle.getItemDetail(slot, true)
        return isSeed(item)
      end)

      turtle.placeDown()
    end

    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()
end

local function replantProcedure()
  if localPlan == nil then
    retrieveLocalPlan()
  end

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

  local remotePlan = fetchRemotePlan()

  if remotePlan == nil then
    error('cannot fetch the remote plan')
  end

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

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

  if utils.sizeof(seedsToPlant) > 0 then
    if retrieveSeeds(seedsToPlant) then
      replantSeeds()
    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 hasEnoughFuel() then
    turtleUtils.refuelAllFromInventory()
  end

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

  retrieveHomePositionProcedure()

  local cycleNumber = 1

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

    dropAllProcedure()
    refuelProcedure()

    replantProcedure()

    goToHarvestPoint()
    harvestProcedure()
    goBackToHome()

    cycleNumber = cycleNumber + 1
  end

  net.closeRednet()
end

main()