--[[
Allows a turtle to keep track of it's
location using a coordinate system.

Use the commands goForward(), goRight(),
goLeft(), goUp(), and goDown() to
control the turtle while adding to
the coordinates.

goHome() will send the turtle back to
it's origin and will point it north:
the direction it was originally facing.

A turtle always faces north when it is placed down
]]--

x = 0
y = 0
z = 0

saveX = 0
saveY = 0
saveZ = 0
saveDirection = NORTH
global map = {}

NORTH = 1
EAST = 2
SOUTH = 3
WEST = 4

UP = 5
DOWN = 6

RIGHT = 7
LEFT = 8

direction = NORTH

--[[sends a turtle forward 1 block
and adds to it's X coordinate]]--
function goForward()
  if turtle.forward() then
    addToCoords(direction)
    return true
  else return false
  end
end

--[[sends a turtle up 1 block
and adds to it's Z coordinate]]--
function goUp()
  if turtle.up() then
    addToCoords(UP)
    return true
  else return false
  end
end

--[[sends a turtle down 1 block
and subtracts from it's Z coordinate]]--
function goDown()
  if turtle.down() then
    addToCoords(DOWN)
    return true
  else return false
  end
end

--[[turns a turtle right and changes
it's direction accordingly]]--
function goRight()
  turtle.turnRight()
  changeDirection(RIGHT)
end

--[[turns a turtle left and changes
it's direction accordingly]]--
function goLeft()
  turtle.turnLeft()
  changeDirection(LEFT)
end

--[[digs the block in front of the turtle and
sends it forward, keeping track of it's coordinates]]--
function goDig()
  turtle.dig()
  goForward()
end

--[[digs the block above the turtle and sends it
up, keeping track of the coordinates]]--
function goDigUp()
  turtle.digUp()
  goUp()
end

--[[digs the block below the turtle and sends it
down, keeping track of it's coordinates]]--
function goDigDown()
  turtle.digDown()
  goUp()
end

--[[sends a turtle home and refuels it from a chest
below it's origin]]--
function goRefuel()
  goHome()
  turtle.suckDown(64)
  turtle.select(1)
  turtle.refuel()
end

--[[moves a turtle forward a specified number of blocks]]--
function move(distance)
  for i=1,distance do
    goForward()
  end
end

--[[moves a turtle up a specified number of blocks]]--
function moveUp(distance)
  for i=1,distance do
    goUp()
  end
end

--[[moves a turtle down a specified number of blocks]]--
function moveDown(distance)
  for i=1,distance do
    goDown()
  end
end

function autoGoForward()
  distanceHome = math.abs(x)+math.abs(y)+math.abs(z)
  if distanceHome < turtle.getFuelLevel()-1 then
    goForward()
  else saveAndFuel() end
end

function autoGoUp()
  distanceHome = math.abs(x)+math.abs(y)+math.abs(z)
  if distanceHome < turtle.getFuelLevel()-1 then
    goUp()
  else saveAndFuel() end
end

function autoGoDown()
  distanceHome = math.abs(x)+math.abs(y)+math.abs(z)
  if distanceHome < turtle.getFuelLevel()-1 then
    goDown()
  else saveAndFuel() end
end

function autoMove(distance)
  for i=1,distance do
    autoGoForward()
  end
end

function autoMoveUp(distance)
  for i=1,distance do
    autoGoUp()
  end
end

function autoMoveDown(distance)
  for i=1,distance do
    autoGoDown()
  end
end

--[[takes the direction of the turtle and adds 1
to the appropriate coordinate based on that direction]]--
function addToCoords(direction)
  if direction == NORTH then
    x = x+1
  elseif direction == EAST then
    y = y+1
  elseif direction == SOUTH then
    x = x-1
  elseif direction == WEST then
    y = y-1
  elseif direction == UP then
    z = z+1
  else
    z = z-1
  end
end

--[[takes a direction turned (right or left) and changes the
direction of the turtle to north, south, east, or west]]--
function changeDirection(turned)
  if turned == RIGHT then
    if direction == NORTH then
      direction = EAST
    elseif direction == EAST then
      direction = SOUTH
    elseif direction == SOUTH then
      direction = WEST
    else
      direction = NORTH
    end
  else
    if direction == NORTH then
      direction = WEST
    elseif direction == WEST then
      direction = SOUTH
    elseif direction == SOUTH then
      direction = EAST
    else
      direction = NORTH
    end
  end
end

--[[takes a direction (north, east, south, or west) and turns
the turtle in that direction]]--
function setDirection(newDirect)
  while true do
    if newDirect == direction then
      break
    end
    goRight()
  end
end

--[[based on the current coordinates of a turtle, send the turtle
back on the x axis, then the y axis, then the z axis]]--
function goHome()
  moved = false
  attempts = 0
  rightDirection = true
  leftDirection = false
  while x~=0 or y~=0 or z~=0 do

    if x > 0 then
      setDirection(SOUTH)
    else
      setDirection(NORTH)
    end
    while math.abs(x) > 0 and not turtle.detect() do
      goForward()
      moved = true
    end

    if y > 0 then
      setDirection(WEST)
    else
      setDirection(EAST)
    end
    while math.abs(y) > 0 and not turtle.detect() do
      goForward()
      moved = true
    end

    while z > 0 and not turtle.detectDown() do
      goDown()
    end
    while z < 0 and not turtle.detectUp() do
      goUp()
      moved = true
    end

    if moved == false then
      mazeSolve()
    end

    moved = false
  end
  setDirection(NORTH)
end

function saveAndFuel()
  saveCoords()
  goRefuel()
  returnToCoords()
end

function saveCoords()
  saveX = x
  saveY = y
  saveZ = z
  saveDirection = direction
end

function returnToCoords()
  x = -saveX
  y = -saveY
  z = -saveZ
  goHome()
  setDirection(saveDirection)
  x = saveX
  y = saveY
  z = saveZ
end

--[[write the main code down here]]--

--[[solves mazes]]--
function mazeSolve()
  layer = 1
  while not returned() do
    try(map(layer,map))
    layer = layer + 1
  end
end

--[[saves a map of the world around the turtle based on spaces away from the
turtle. all the empty spaces will be marked as  true and the spaces blocked
by a block will be marked as false]]--
function map(layer, map)

  print("made it")

  for i=1,layer do

    print("made it")

    saveCoords()
    move(layer)
    map[layer][direction] = turtle.detect()
    returnToCoords()
    goRight()
  end

  for i=1,layer do
    saveCoords()
    moveUp(layer)
    map[layer][UP] = turtle.detectUp()
    returnToCoords()
  end

  for i=1,layer do
    saveCoords()
    moveDown(layer)
    map[layer][DOWN] = turtle.detectDown()
    returnToCoords()
  end
  return map
end

--[[tries a layer to see if a turtle can go home by unsticking itself]]--
function try(map)
  for i=1,4 do
    if map[layer][direction] then
      move(layer)
      goHome()
      if returned() then break end
    end
  end
end

function returned()
  return x==0 and y==0 and z==0
end

autoMove(15)
goRight()
autoMove(30)
autoMoveUp(15)
goHome()