nav.lua

local robot = require("robot")
local computer = require("computer")
local component = require("component") -- TODO remove
local event = require("event")
local clsNav = {}
clsNav.title = "Navigation Library"
clsNav.shortTitle = "nav"
clsNav.version = 0.9000
function clsNav:new(oldObject)
  local object
  if oldObject
    and type(oldObject.title) == "string"
    and oldObject.title == self.title
    and type(oldObject.title) == "number"
    and oldObject.version <= self.version
  then
    object = oldObject
  else
    object = {}
  end
  setmetatable(object, self)
  self.__index = self
  return object
end

---------------- Dependencies -------------------------------------------------
local logger = logger or {}
if not logger.fatal then
  logger.fatal = function (...) io.write(string.format(...)) end
end
if not logger.warning then
    logger.warning = function (...) io.write(string.format(...)) end
end
if not logger.info then
    logger.info = function (...) --[[io.write(string.format(...))]] end
end
if not logger.spam then
    --local fs = require("filesystem")
    --fs.makeDirectory("logs")
    logger.spam = function (...)
    --  local file = fs.open("logs/test.log","a")
    --  file:write(string.format(...))
    --  file:close()
     -- io.write(string.format(...))
    end
end
local utils = utils or {}
local stoping = false
local moitarg
if not utils.deepCopy then
  function utils.deepCopy(t)
    -- Credits to MihailJP @ https://gist.github.com/MihailJP/3931841
    if type(t) ~= "table" then return t end
    --local meta = getmetatable(t)
    local target = {}
    for k, v in pairs(t) do
      if type(v) == "table" then
        target[k] = utils.deepCopy(v)
      else
        target[k] = v
      end
    end
    --setmetatable(target, meta)
    return target
  end
end
if not utils.deepMerge then
  function utils.deepMerge(t1, t2) -- merges t1 over t2
    if type(t1) ~= "table" then return t1 end
    --local meta1 = getmetatable(t1)
    local target = utils.deepCopy(t2)
    for k, v in pairs(t1) do
        if (type(v) == "table") and (type(target[k] or false) == "table") then
            utils.deepMerge(target[k], t1[k])
        else
            target[k] = v
        end
    end
    --setmetatable(target, meta1)
    return target
  end
end
if not utils.freeMemory then
  function utils.freeMemory()
    local result = 0
    for i = 1, 10 do
      result = math.max(result, computer.freeMemory())
      os.sleep(0)
    end
    return result
  end
end
local thread = thread or {}
if not thread.yield then thread.yield = function() os.sleep() end end

---------------- Local variables ----------------------------------------------
local mapGrid = {
  {"A","B","C","D","E",},
  {"F","G","H","I","J",},
  {"K","L","M","N","O",},
  {"P","Q","R","S","T",},
  {"U","V","W","X","Y",},
}
local mapMaxDepth = 1

---------------- Local functions ----------------------------------------------
local function checkOptions(unknowns, ...)
    local wishlist = {...}
    if type(unknowns) ~= "table" then unknowns = {unknowns} end
  for _,wish in pairs(wishlist) do
    if type(wish) == "string" then
      for _,unknown in pairs(unknowns) do
        if type(unknown) == "string" and wish == unknown then return unknown end
      end
    end
  end
  return false
end
local function checkPos(unknown)
  if type(unknown) ~= "table" then return false end
  if
    type(unknown.x) == "number"
    and type(unknown.y) == "number"
    and type(unknown.z) == "number"
  then
    return {
      x = unknown.x,
      y = unknown.y,
      z = unknown.z,
      f = (type(unknown.f) == "number" and unknown.f) or nil,
      weight = (type(unknown.weight) == "number" and unknown.f) or nil,
    }
  elseif
    type(unknown[1]) == "number"
    and type(unknown[2]) == "number"
    and type(unknown[3]) == "number"
  then
    return {
      x = unknown[1],
      y = unknown[2],
      z = unknown[3],
      f = (type(unknown[4]) == "number" and unknown[4]) or nil,
      weight = (type(unknown[5]) == "number" and unknown[5]) or nil,
    }
  end
  return false
end
local function checkPositions(unknown)
  if type(unknown) ~= "table" then return false end
  local positions = {}
    if checkPos(unknown) then positions[#positions+1] = checkPos(unknown) end
  for k,v in pairs(unknown) do
    local pos = checkPos(v)
    if pos then
      positions[#positions+1] = pos
    end
  end
  if #positions > 0 then
    return positions
  else
    return false
  end
end

---------------- Object variables ---------------------------------------------
clsNav.pos = {
    x = 0, -- North
    z = 0, -- East
    y = 0, -- Height
    f = 0, -- Facing direction, modulus of 4 // 0,1,2,3 = North, East, South, West
}
clsNav.map = {
  _initialized = os.time(),
    _updated = os.time(),
  _maxDepth = 1,
}

---------------- Methods ------------------------------------------------------
function clsNav:getVersion()
    return self.version
    end
function clsNav:getMapFromPos(pos)
  pos = checkPos(pos)
  if not pos then return false end
  local chunkName = ""
  local chunkX = (pos.x-pos.x%16)/16
  local chunkY = -(pos.y-pos.y%16)/16 -- invert so that (-1,-1) is at bottom left, NOT up left
  local power = 1
  while chunkX > 0 or chunkY > 0 or self.map._maxDepth > #chunkName do
    local gridX = (chunkX+2)%5-2
    local gridY = (chunkY+2)%5-2
    chunkX = (chunkX+2 - (chunkX+2)%5)/5
    chunkY = (chunkY+2 - (chunkY+2)%5)/5
    chunkName = mapGrid[gridY+3][gridX+3]..chunkName
  end
  self.map._maxDepth = math.max(self.map._maxDepth, #chunkName)
  local posNo = 10000*pos.z + 100*pos.x + pos.y
  return chunkName, posNo
end
function clsNav:putMap(pos, value)
  if type(value) ~= "table" then return false end -- to delete do putMap(pos,{})
  local chunkName, posNo = self:getMapFromPos(pos)
  if (not chunkName) or (not posNo) then return false end

  if not self.map[chunkName] then
    -- check for filesystem files, otherwise...
    self.map[chunkName] = {}
  end

  if not self.map[chunkName][posNo] then self.map[chunkName][posNo] = {} end

  self.map._updated = os.time()
  self.map[chunkName]._accessed = os.time()
  self.map[chunkName]._updated = os.time()
  value._updated = os.time()
  self.map[chunkName][posNo] = utils.deepMerge(value, self.map[chunkName][posNo])
  return true
end
function clsNav:setPos(pos_or_face)
  ----logger.spam("Nav:setPos(%s)\n",pos_or_face)
  pos = checkPos(pos_or_face)
  if pos then
    self.pos = pos
  else
    self.pos = self:getPos(pos_or_face)
  end
end
function clsNav:comparePos(poslist1,poslist2,isFaced) -- input either pos or tables of pos
  poslist1 = checkPositions(poslist1)
  if type(poslist1) ~= "table" then return false, 123, "comparePos: No legal pos in argument #1" end
  poslist2 = checkPositions(poslist2)
  if type(poslist2) ~= "table" then return false, 123, "comparePos: No legal pos in argument #2" end

    for i,pos1 in pairs(poslist1) do
        ----logger.spam("Pos1(%s): %s,%s,%s,%s\n", i, Pos1.x, Pos1.z, Pos1.y, Pos1.f)
    for j,pos2 in pairs(poslist2) do
      ----logger.spam("  Pos2(%s): %s,%s,%s,%s\n", j, Pos2.x, Pos2.z, Pos2.y, Pos2.f)
      if
        pos1.x == pos2.x
        and pos1.y == pos2.y
        and pos1.z == pos2.z
      then
        if
          (isFaced
          and pos1.f
          and pos2.f
          and pos1.f == pos2.f)
          or
          (not isFaced)
        then
          return pos1, pos2
        end
      end
        end
  end

    return false
end
function clsNav:getPos(pos, dir) -- Input Position (table), FacingDirection (num) in any order
  if type(dir) == "nil" and type(pos) == "number" then
    dir = pos%6
    pos = nil
    elseif type(dir) == "number" then
    dir = dir%6
  else
    dir = nil
  end
  pos = checkPos(pos or self.pos)
  if not pos then return false, "Failed to lookup pos" end

    if dir == nil then return pos
    elseif dir == 0 then return {["x"] = pos.x+1, ["y"] = pos.y, ["z"] = pos.z, ["f"] = dir}
    elseif dir == 1 then return {["x"] = pos.x, ["y"] = pos.y+1, ["z"] = pos.z, ["f"] = dir}
    elseif dir == 2 then return {["x"] = pos.x-1, ["y"] = pos.y, ["z"] = pos.z, ["f"] = dir}
    elseif dir == 3 then return {["x"] = pos.x, ["y"] = pos.y-1, ["z"] = pos.z, ["f"] = dir}
    elseif dir == 4 then return {["x"] = pos.x, ["y"] = pos.y, ["z"] = pos.z+1, ["f"] = pos.f}
    elseif dir == 5 then return {["x"] = pos.x, ["y"] = pos.y, ["z"] = pos.z-1, ["f"] = pos.f}
    end

    return false
end
function clsNav:getMap(pos)
  local chunkName, posNo = self:getMapFromPos(pos)
  if (not chunkName) or (not posNo) then return false, "Bad arguments" end

  if not self.map[chunkName] then
    -- check for filesystem files, otherwise...
    return {}
  end

  if not self.map[chunkName][posNo] then return {} end

  self.map[chunkName]._accessed = os.time()
  return utils.deepCopy(self.map[chunkName][posNo])
end
function clsNav:detectAround() -- TODO: add other detections, repair tagging
    ----logger.Check("detectAround:%s,%s",location,value)
  local _,substance = robot.detect()
  self:putMap(self:getPos(self:getPos().f),{["substance"]=substance})
  if substance=="solid" then
    os.sleep(0)
    robot.suck()
  end
  _,substance = robot.detectUp()
  self:putMap(self:getPos(4),{["substance"]=substance})
  if substance=="solid" then
    os.sleep(0)
    robot.suckUp()
  end
  _,substance = robot.detectDown()
  self:putMap(self:getPos(5),{["substance"]=substance})
  if substance=="solid" then
    os.sleep(0)
    robot.suckDown()
  end
end
function clsNav:getPath(targets, options)
    --This code (Aug, 2014) is written by Akuukis
    --  who based on code (Sep 21, 2006) by Altair
    --      who ported and upgraded code of LMelior

  local options = options or {}
  local upvalues = {} -- upvalue, anti-crashing mechanism
  local pathtries = 3
  local function serializePos(pos)
    return string.format("%05s",pos.x)..string.format("%05s",pos.y)..string.format("%03s",pos.z)
  end
  local function getHeuristic(startPos, targetPoslist, flag)
    local minCost = math.huge
    for _,targetPos in pairs(targetPoslist) do
      if flag == "manhattan" then
        minCost = math.min(minCost, 1 * (
          (targetPos.pathWeight or 0) +
          math.abs(startPos.x-targetPos.x) +
          math.abs(startPos.y-targetPos.y) +
          math.abs(startPos.z-targetPos.z) )
        )
      elseif flag == "euclidean" then
        minCost = math.min(minCost, (targetPos.pathWeight or 0) + math.abs((
          math.abs(startPos.x-targetPos.x) +
          math.abs(startPos.y-targetPos.y) +
          math.abs(startPos.z-targetPos.z) ) ^ (1/3) )
        )
      else -- manhattan
        minCost = math.min(minCost, 1 * (
          (targetPos.pathWeight or 0) +
          math.abs(startPos.x-targetPos.x) +
          math.abs(startPos.y-targetPos.y) +
          math.abs(startPos.z-targetPos.z) )
        )
      end
    end
    if minCost ~= math.huge then return minCost else error(debug.traceback()) end
  end
  local function getCostBlocks(nextBase, flag)
    local defaultMoveCost = 1 -- cost in time to move 1 square, no diagonal movement.
    local defaultWanderCost = 1 -- average cost to move in unexplored block
    local defaultDestroyCost = 3 -- average cost in time to move 1 square with solid block inside
    if nextBase.substance == "air" then
      if flag == "careful" then
        return defaultMoveCost
      elseif flag == "normal" then
        return defaultMoveCost
      elseif flag == "simple" then
        return defaultMoveCost
      elseif flag == "brutal" then
        return defaultMoveCost
      end
    elseif nextBase.substance == "replaceable" then
      if flag == "careful" then
        return defaultMoveCost
      elseif flag == "normal" then
        return defaultMoveCost
      elseif flag == "simple" then
        return defaultMoveCost
      elseif flag == "brutal" then
        return defaultMoveCost
      end
    elseif nextBase.substance == "solid" then
      if flag == "careful" then
        return false
      elseif flag == "normal" then
        return defaultDestroyCost
      elseif flag == "simple" then
        return defaultMoveCost
      elseif flag == "brutal" then
        return defaultMoveCost
      end
    elseif nextBase.substance == "liquid" then
      if flag == "careful" then
        return false
      elseif flag == "normal" then
        return defaultDestroyCost
      elseif flag == "simple" then
        return defaultMoveCost
      elseif flag == "brutal" then
        return defaultDestroyCost
      end
    elseif nextBase.substance == "entity" then
      if flag == "careful" then
        return defaultMoveCost
      elseif flag == "normal" then
        return defaultMoveCost
      elseif flag == "simple" then
        return defaultMoveCost
      elseif flag == "brutal" then
        return defaultMoveCost
      end
    else
      return defaultWanderCost
    end
  end
  local function getCostTurn(curBase, dir, flag)
    if flag == "simple" then return 0 end
    local defaultTurnCost = 0.9 -- cost in time to turn 90 degrees
    local turnCost = 0
    if (not curBase.f) or curBase.f == dir or dir == 4 or dir == 5 then
      return 0
    elseif (dir-curBase.f)%4 == 2 then
      return 2 * defaultTurnCost
    else
      return 1 * defaultTurnCost
    end
  end
  local function getModTags(nextBase, flag)
    local defaultRoadMod = 0.1 -- cost modifier for moving along roads
    if nextBase.tag then
      if flag == "careful" or flag == "normal" then
        if nextBase.tag.evade then
          return false
        elseif nextBase.tag.road then
          return defaultRoadMod
        end
      elseif flag == "simple" then
        if nextBase.tag.evade then
          return false
        end
      elseif flag == "brutal" then
        -- ignore tags
      end
    end
    return 1
  end
  local function tryPath(starts, targets, options)

    starts = checkPositions(starts)
    if (not starts) or (not next(starts)) then return false, "No legal start provided" end
    --for k,v in pairs(starts) do
    --  --logger.spam("tryPath: Start %s/%s (%2s,%2s,%2s,%2s,%2s)\n", k,#starts,v.x,v.y,v.z,v.f,v.weight)
    --end
    targets = checkPositions(targets)
    if (not targets) or (not next(targets)) then return false, "No legal target provided" end
    --for k,v in pairs(targets) do
    --  --logger.spam("tryPath: Target %s/%s (%2s,%2s,%2s,%2s,%2s)\n", k,#targets,v.x,v.y,v.z,v.f,v.weight)
    --end

    local defaultHeurMod = 1 -- cost modifier for heuristics. Keep it big enough!
    local flag = checkOptions(options, "careful", "normal", "simple", "brutal") or "normal"
    local flag2 = checkOptions(options, "manhattan", "euclidean") or "manhattan"
    local flag3 = checkOptions(options, "forwards", "backwards", "bidirectional") or "bidirectional"
    --for k,v in pairs(options) do
    --  --logger.spam("tryPath: Option %s/%s %s\n", k,#options,v)
    --end

    --logger.info("Pathfinding: %s starts, %s targets, %s options.\n",#starts,#targets,#options + ((options._path and 1) or 0))

    options = nil
    local SCL, SNL, SOL, TCL, TNL, TOL = {}, {}, {min={weight=math.huge}}, {}, {}, {min={weight=math.huge}}
    for i=1,#starts do
      local key = serializePos(starts[i])
      if not SNL[key] then
        local nextBase = self:getMap(starts[i])
        local costBlocks = getCostBlocks(nextBase, flag)
        local modTag = getModTags(nextBase, flag)
        if costBlocks and modTag then
          SNL[key] = starts[i] -- x,y,z,f
          SNL[key].pathWeight = (SNL[key].weight or 0) + costBlocks * modTag
          SNL[key].heurWeight = getHeuristic(starts[i], targets, flag2) * defaultHeurMod
          SNL[key].weight = SNL[key].pathWeight + SNL[key].heurWeight
          SNL[key].parent = false
          SNL.min = SNL.min or {}
          SNL.min.weight = math.min(SNL.min.weight or math.huge, SNL[key].weight)
        end
      end
    end
    for i=1,#targets do
      local key = serializePos(targets[i])
      if not TNL[key] then
        local nextBase = self:getMap(targets[i])
        local costBlocks = getCostBlocks(nextBase, flag)
        local modTag = getModTags(nextBase, flag)
        if costBlocks and modTag then
          TNL[key] = targets[i] -- x,y,z,f
          TNL[key].pathWeight = (TNL[key].weight or 0) + costBlocks * modTag
          TNL[key].heurWeight = getHeuristic(targets[i], starts, flag2) * defaultHeurMod
          TNL[key].weight = TNL[key].pathWeight + TNL[key].heurWeight
          TNL[key].parent = false
          TNL.min = TNL.min or {}
          TNL.min.weight = math.min(TNL.min.weight or math.huge, TNL[key].weight)
        end
      end
    end

    if (not starts) or (not next(starts)) then return false, "No legal start left, all filtered" end
    if (not targets) or (not next(targets)) then return false, "No legal target left, all filtered" end
    --logger.info("Searching.")

    local side = false
    local closedk = 0
    local timer = os.time()
    while true do

      if flag3 == "forwards" then
        side = true
      elseif flag3 == "backwards" then
        side = false
      elseif flag3 == "bidirectional" then
        side = not side -- switch sides
      end

      local openlist = (side and SOL) or TOL
      local openlistNew = (side and SNL) or TNL
      local closedlist = (side and SCL) or TCL
      local targetlist = (side and {TCL.last, table.unpack(targets)}) or {SCL.last, table.unpack(starts)}

      local temp1, temp2 = openlist.min, openlistNew.min
      openlist.min, openlistNew.min = nil, nil
      if (not next(openlist)) and (not next(openlistNew)) then return false, "trapped in box or illegal targets" end -- trapped in box, cannot find path
      openlist.min, openlistNew.min = temp1, temp2

      do  -- Find next node with the lowest weight (Prefer newer nodes)
        local searchlist = (openlist.min.weight < openlistNew.min.weight and openlist) or openlistNew
        local lowestDS = math.huge
        searchlist.min.weight = math.huge
        local basis = nil
        for k,node in pairs(searchlist) do
          if (node.weight or math.huge) < searchlist.min.weight then
            if node.weight < lowestDS then
              searchlist.min.weight = lowestDS
              lowestDS = node.weight
              basis = k
            else
              searchlist.min.weight = node.weight
            end
          end
        end
        closedlist[basis] = searchlist[basis]
        closedlist[basis].key = basis
        closedlist.last = closedlist[basis]
        closedk = closedk + 1
        searchlist[basis] = nil
        for k,node in pairs(openlistNew) do
          if k ~= "min" then
            openlist[k] = node
            openlistNew[k] = nil
          else
            openlist.min.weight = math.min(node.weight,openlist.min.weight)
            openlistNew.min.weight = math.huge
          end
        end
      end
      local curBase = closedlist.last

      if self:comparePos(curBase,targetlist,false) then -- check if we have reached one of targetlist..
        SOL, TOL, SNL, TNL, openlist, openlistNew, targetlist = nil, nil, nil, nil, nil, nil, nil -- free some RAM

        local startlist, endlist = SCL, TCL
        local startBase, endBase = nil, nil
        for k,target in pairs(startlist) do
          if self:comparePos(curBase,target,false) then startBase = target end
        end
        for k,target in pairs(endlist) do
          if self:comparePos(curBase,target,false) then endBase = target end
        end

        if
          ((not startBase) or startBase.parent == false)
          and ((not endBase) or endBase.parent == false)
        then return {}, {}, 0 end -- if we started at target

        local function extractPath(list,base)
          if not base then return {} end
          local path = {[1] = base}
          while path[#path].parent do
            path[#path+1] = list[path[#path].parent]
            list[path[#path-1].parent] = nil
            if #path%100==0 then thread.yield() end
          end
          return path
        end

        local startPath = extractPath(startlist, startBase) -- backwards
        local endPath = extractPath(endlist, endBase) -- backwards

        local path = {}
        for i=1,#startPath do path[#path+1] = startPath[#startPath-i+1] end
        path[#path]=nil
        for i=1,#endPath do path[#path+1] = endPath[i] end

        -- Change list of XZ coordinates into a list of directions
        --logger.spam("dirPath. ")
        thread.yield()
        local dirPath = {}
        for i=1,#path-1 do
          if path[i+1].x > path[i].x then dirPath[i]=0 -- North
          elseif path[i+1].y > path[i].y then dirPath[i]=1 -- East
          elseif path[i+1].x < path[i].x then dirPath[i]=2 -- South
          elseif path[i+1].y < path[i].y then dirPath[i]=3 -- West
          elseif path[i+1].z > path[i].z then dirPath[i]=4 -- Up
          elseif path[i+1].z < path[i].z then dirPath[i]=5 -- Down
          end
          --logger.spam("%s,", dirPath[i])
        end
        --logger.spam("\n")
        return dirPath, path
      end

      for dir=0,5 do
        local nextPos = self:getPos(curBase,dir)
        local nextKey = serializePos(nextPos)
        if not closedlist[nextKey] then
          local nextBase = self:getMap(nextPos)
          local costBlocks = getCostBlocks(nextBase, flag)
          local costTurn = getCostTurn(curBase, dir, flag)
          local modTag = getModTags(nextBase, flag)
          if costBlocks and costTurn and modTag then
            openlistNew[nextKey] = nextPos -- x,y,z,f
            openlistNew[nextKey].pathWeight = curBase.pathWeight + (costBlocks + costTurn) * modTag
            openlistNew[nextKey].heurWeight = getHeuristic(nextPos, targetlist, flag2) * defaultHeurMod
            openlistNew[nextKey].weight = openlistNew[nextKey].pathWeight + openlistNew[nextKey].heurWeight
            if openlist[nextKey] and openlist[nextKey].weight < openlistNew[nextKey].weight then
              openlistNew[nextKey] = nil
            else
              openlist[nextKey] = nil
              openlistNew[nextKey].parent = curBase.key
              openlistNew.min.weight = math.min(openlistNew.min.weight or math.huge, openlistNew[nextKey].weight)
            end
          end
        end
      end

      do  -- find lowest weight for closedlist to add as lastTarget
        local lowestDS = curBase.weight or math.huge
        local lowestHeurWeight = curBase.heurWeight or math.huge
        local basis = "last"
        for k,node in pairs(closedlist) do
          if (node.weight or math.huge) < lowestDS then
            lowestDS = node.weight
            basis = k
          end
          if (node.heurWeight or math.huge) < lowestHeurWeight then
            lowestHeurWeight = node.heurWeight
          end
        end
        if side then
          upvalues.starts = {closedlist[basis], curBase}
        else
          upvalues.targets = {closedlist[basis], curBase}
        end
        upvalues.minHeurWeight = math.min(upvalues.minHeurWeight or math.huge, lowestHeurWeight)
        upvalues.cycles = (upvalues.cycles or 0) + 1
      end

      thread.yield()
    end
    return false
  end
  local oldUpvalues = {starts={},targets={},minHeurWeight=math.huge}
  repeat

    local ok, dirPath, path = pcall(
      tryPath,
      utils.deepCopy(upvalues.starts or {self:getPos()}),
      utils.deepCopy(upvalues.targets or targets),
      options
    )
    --logger.info("\n")

    if ok then
      if not dirPath then
        return false, path -- error
      elseif self:comparePos(path[1],self:getPos(),false) then
        if self:comparePos(path[#path],targets,false) then
          return dirPath, path, true, upvalues.cycles -- full path
        else
        end
      else
        --logger.spam("Found another start: %s,%s,%s,%s\n",path[1].x,path[1].y,path[1].z,path[1].f)
        targets = path[1] -- search to new target that leads to real target
        upvalues.starts = nil
        pathtries = 3
        options._path = nil
      end
    else
      --logger.spam("Searching failed: %s\n",dirPath)
    end

    if pathtries == 3 then
      --logger.spam("Retry with 'backwards'\n")
      pathtries = pathtries - 1
      options._path = "backwards"
    elseif pathtries == 2 then
      if upvalues.minHeurWeight < oldUpvalues.minHeurWeight then
        --logger.spam("Continue with 'backwards' %s/%s\n",upvalues.minHeurWeight,oldUpvalues.minHeurWeight)
        oldUpvalues.minHeurWeight = upvalues.minHeurWeight
      else
        --logger.spam("Retry with 'forwards'\n")
        pathtries = pathtries - 1
        options._path = "forwards"
      end
    elseif pathtries == 1 then
      if upvalues.minHeurWeight < oldUpvalues.minHeurWeight then
        --logger.spam("Continue with 'forwards' %s/%s\n",upvalues.minHeurWeight,oldUpvalues.minHeurWeight)
        oldUpvalues.minHeurWeight = upvalues.minHeurWeight
      else
        --logger.spam("Retry with 'bidirectional'\n")
        pathtries = pathtries - 1
        options._path = "bidirectional"
      end
    elseif pathtries == 0 then
      if upvalues.minHeurWeight < oldUpvalues.minHeurWeight then
        --logger.spam("Continue with 'bidirectional' %s/%s\n",upvalues.minHeurWeight,oldUpvalues.minHeurWeight)
        oldUpvalues.minHeurWeight = upvalues.minHeurWeight
      else
        --logger.spam("lastTargets %s at (%s,%s,%s)\n",lastTargets, lastTargets and lastTargets.x, lastTargets and lastTargets.y, lastTargets and lastTargets.z)
        return false
      end
    end

    thread.yield()
  until pathtries < 0

end
function clsNav:move(dir, options) -- dir={0=North|1=East|2=South|3=West|4=up|5=down}, returns true if succeeded

  local flag = checkOptions(options, "careful", "normal", "simple", "brutal") or "normal"
  local flag2 = checkOptions(options, "fast", "explore", "patrol") or "fast"

    if not self:turnTo(dir) then return false, "no dir provided" end
  for dir=0,3 do -- look around
    if
      (flag2 == "patrol") or
      (flag2 == "explore" and not self:getMap(self:getPos(dir))._updated)
    then
      self:turnTo(dir)
    end
  end
    if dir ~= self:getPos().f then self:turnTo(dir) end

    if flag == "careful" or flag == "normal" or flag == "simple" then
    local pos = self:getMap(self:getPos(dir))
    if pos and pos.tag then
      return false, "Tagged as "..pos.tag
    end
  end

    -- if flag == "careful" then
 --    local substance
 --    if dir == 4 then _, substance = robot.detectUp()
 --    elseif dir == 5 then _, substance = robot.detectDown()
 --    else _, substance = robot.detect()
 --    end
 --    if substance ~= "air" and substance ~= "replaceable" then return false, substance end
 --  end

  local ok, reason
  if dir == 4 then
    while flag ~= "careful" and robot.detectUp() do robot.swingUp() end
    ok, reason = robot.up()
  elseif dir == 5 then
    while flag ~= "careful" and robot.detectDown() do robot.swingDown() end
      ok, reason = robot.down()
  else
    while flag ~= "careful" and robot.detect() do robot.swing() end
    ok, reason = robot.forward()
  end
  if ok then
    self:setPos(dir)
    ----logger.spam("Nav.Move() Return true\n")
    return true
    else
    return false, reason
    end
    return false, "Unexpected error"
end

-- Core methods
function clsNav:turnRight()
    robot.turnRight()
    ----logger.spam("Nav.turnRight() Nav.Pos.f. %s => ",self:getPos().f)
    self.pos.f = (self:getPos().f+1)%4
    ----logger.spam("%s\n",self:getPos().f)
    self:detectAround()
    return true
end
function clsNav:turnLeft()
    robot.turnLeft()
    ----logger.spam("Nav:turnLeft() Nav.Pos.f. %s => ",self:getPos().f)
    self.pos.f = (self:getPos().f+3)%4
    ----logger.spam("%s\n",self:getPos().f)
    self:detectAround()
    return true
end
function clsNav:turnAround()
    if 1==math.floor(math.random(0,1)+0.5) then
        self:turnRight()
        self:turnRight()
    else
        self:turnLeft()
        self:turnLeft()
    end
    return true
end

function clsNav:stopgo()
  stoping=true
end

function clsNav:gettarg()
  return moitarg
end

function clsNav:go(targets, options) -- table target1 [, table target2 ...] text option1 [, text option2 ...]
    moitarg=targets
  local timer = os.time()
  targets = checkPositions(targets) -- Filters legal targets
  if (not targets) or (not next(targets)) then targets = {checkPos({0,0,0,0})} end

    local flag = checkOptions(options, "absolute", "relative", "relFace") or "absolute"
    if flag == "relative" then
        for j in ipairs(targets) do
            targets[j].x = targets[j].x + self:getPos().x
            targets[j].y = targets[j].y + self:getPos().y
            targets[j].z = targets[j].z + self:getPos().z
        end
    end
    if flag == "relFace" then
        for j in ipairs(targets) do
            targets[j].x = targets[j].x + self:getPos().x
            targets[j].y = targets[j].y + self:getPos().y
            targets[j].z = targets[j].z + self:getPos().z
            if self:getPos().f == 0 then targets[j].x = self:getPos().x + targets[j].x; targets[j].y = self:getPos().y + targets[j].y end
            if self:getPos().f == 1 then targets[j].x = self:getPos().x - targets[j].y; targets[j].y = self:getPos().y + targets[j].x end
            if self:getPos().f == 2 then targets[j].x = self:getPos().x - targets[j].x; targets[j].y = self:getPos().y - targets[j].y end
            if self:getPos().f == 3 then targets[j].x = self:getPos().x + targets[j].y; targets[j].y = self:getPos().y - targets[j].x end
        end
    end

    local tries = 2 -- TODO

  while tries <= 2 do

        local destination = self:comparePos(targets, self:getPos())
        if destination then
            self:turnTo(destination.f)
            return true
        end

    local dirPath,err,ok,cycles = self:getPath(targets,options)
        if not dirPath then -- TODO: Cannot find path!
      if tries == 1 then
        os.sleep(2)
        self:detectAround()
        self:turnAround()
        self:turnAround()
        print("detected")
      end
      tries = tries + 1
        else
      tries=1
      local i = 1
      local ok, err = true, ""
      while i <= #dirPath and (ok or err == "no dir provided") do
        thread.yield()
        if stoping then
          break
        end
        ok, err = self:move(dirPath[i], options)
        if err == "solid" then
          self:detectAround()
        end
        i = i + 1
      end
    end
    if stoping then
      break
    end
    end
  stoping = false
    return false, "Go: Aborting, exceeded retries"
end

-- Shortcut methods
function clsNav:turnTo(dir)
    if type(dir) ~= "number" then return false end
  if type(dir) == "nil" or dir >= 4 then return true end
    if dir==self:getPos().f or dir==self:getPos().f+4 then return true
    elseif dir==self:getPos().f-1 or dir==self:getPos().f+3 then return self:turnLeft()
    elseif dir==self:getPos().f-2 or dir==self:getPos().f+2 then return self:turnAround()
    elseif dir==self:getPos().f-3 or dir==self:getPos().f+1 then return self:turnRight()
    end
end
function clsNav:step(options)
    return self:move(self:getPos().f,options)
end
function clsNav:stepUp(options)
    return self:move(4,options)
end
function clsNav:stepDown(options)
    return self:move(5,options)
end
function clsNav:goNextTo(center, options)
    local SixTargets = {}
    for i=0,5 do
        SixTargets[i+1] = self:getPos(center,i)
    end
    SixTargets[1].f = 2
    SixTargets[2].f = 3
    SixTargets[3].f = 0
    SixTargets[4].f = 1
    SixTargets[5].f = nil
    SixTargets[6].f = nil
    self:go( SixTargets[1], SixTargets[2], SixTargets[3], SixTargets[4], SixTargets[5], SixTargets[6], options )
end
function clsNav:drawMap(offset)
  offset = checkPos(offset)
  local resX, resY = component.gpu.getResolution()

  local lowLeft = self:getPos()
  lowLeft.x = lowLeft.x - (resY+resY%2)/2
  lowLeft.y = lowLeft.y - (resX+resX%2)/2
  if offset then
    lowLeft.x = lowLeft.x + offset.x
    lowLeft.y = lowLeft.y + offset.y
    lowLeft.z = lowLeft.z + offset.z
  end

  for yScreen=1,resY do
    local output = ""
    for xScreen=1,resX do
      local subst = self:getMap({lowLeft.x+yScreen,lowLeft.y+xScreen,lowLeft.z}).substance
      if subst == nil then output = output.." "
      elseif subst == "air" then output = output.."."
      elseif subst == "solid" then output = output.."#"
      elseif subst == "entity" then output = output.."e"
      elseif subst == "liquid" then output = output.."~"
      elseif subst == "replaceable" then output = output..","
      else error(debug.traceback())
      end
    end
    component.gpu.set(1,resY+1-yScreen,output)
  end
  return true
end

return clsNav

---------------- Details & Notes ----------------------------------------------

--[[ Tutorials
General: http://www.lua.org/pil/contents.html
Varargs: http://lua-users.org/wiki/VarargTheSecondClassCitizen
Intro to A* - http://www.raywenderlich.com/4946/introduction-to-a-pathfinding
Try it out! - http://zerowidth.com/2013/05/05/jump-point-search-explained.html
Better version to try out! - https://qiao.github.io/PathFinding.js/visual/
Useful - http://theory.stanford.edu/~amitp/GameProgramming/Heuristics.html
--]]
--[[ Coord system
# MC logic
Coords... North: z--, East: x++, South: z++, West: x--, Up: y++, Down: y--
Coords... X points East, Z points South, Y points Up
Facing... 0: South, 1: West, 2: North, 3: East
Facing... Starts at South, goes clockwise
# Nav logic
Coords... North: x++, East: y++, South: x--, West: y--, Up: z++, Down: z--
Coords... X points North, Y points East, Z points Up
Facing... 0: North, 1: East, 2: South, 4: West
Facing... Starts at North, goes clockwise

use getNavFromMC() or getMCfromNav() to switch if needed, returns table
--]]
--[=[ Map structure
self.map[chunkID][SerializedCoord] = nil --[[unknown--]] or childID --[[if lended--]] or {
  substance = "air" or "solid" or "entity" or "replaceable" or "liquid"
  content = nil --[[unknown--]] or {--[[anything useful--]]}
  updated = 0 -- time in seconds from Colony start
  tag = {[string][,...]} -- RoCoWa related only, like "road", "evade", etc.
--]=]