carriageTurtle

rednet.open("right")

con = "off"

function topToBack() -- move turtle from top of controller to back
   turtle.forward()
   turtle.down()
   turtle.turnRight()
   turtle.turnRight()
   pos = "back"
   file = fs.open("pos", "w")
   file.write(pos)
   file:close()
   eng = peripheral.wrap("front")
end

function backToTop() -- move turtle from behind engine to top
   turtle.up()
   turtle.forward()
   turtle.turnRight()
   turtle.turnRight()
   pos = "top"
   file = fs.open("pos", "w")
   file.write(pos)
   file:close()
   eng = peripheral.wrap("bottom")
end


function goDown()
  dir = 29
  eng.move(0, false, false)
  turtle.down()
  yPos = yPos - 1
  file = fs.open("y", "w")
  file.write(yPos)
  file:close()
  sleep(1)
end

function goUp()
  dir = 42
  eng.move(1, false, false)
  turtle.up()
  yPos = yPos + 1
  file = fs.open("y", "w")
  file.write(yPos)
  file:close()
  sleep(1)
end

function goForward()
  dir = 17
  eng.move(2, false, false)
  os.sleep(1)
  zPos = zPos - 1
  file = fs.open("z", "w")
  file.write(zPos)
  file:close()
  turtle.forward()
end

function goBack()
  dir = 31
  eng.move(3, false, false)
  turtle.forward()
  zPos = zPos + 1
  file = fs.open("z", "w")
  file.write(zPos)
  file:close()
  sleep(1)
end

function goRight()
  dir = 32
  eng.move(5, false, false)
  turtle.turnRight()
  turtle.forward()
  turtle.turnLeft()
  xPos = xPos + 1
  file = fs.open("x", "w")
  file.write(xPos)
  file:close()
  os.sleep(0.2)
end

function goLeft()
  dir = 30
  eng.move(4, false, false)
  turtle.turnLeft()
  turtle.forward()
  turtle.turnRight()
  xPos = xPos - 1
  file = fs.open("x", "w")
  file.write(xPos)
  file:close()
  os.sleep(0.2)
end

function display() -- screen display
term.clear()
x,y = term.getSize()
term.setCursorPos(x/2, y/3-1)
print("W")
term.setCursorPos((x/5*4) - 2, y/3-1)
print("Auto(R)")
term.setCursorPos(x/2-3, y/3)
print("Forward")
term.setCursorPos(x/5*4, y/3)
print(con)
term.setCursorPos(x/5, y/3*2-1)
print("A")
term.setCursorPos(x/2, y/3*2-1)
print("S")
term.setCursorPos(x/5*4, y/3*2-1)
print("D")
term.setCursorPos(x/5-1, y/3*2)
print("Left")
term.setCursorPos(x/2-1, y/3*2)
print("Back")
term.setCursorPos(x/5*4-2, y/3*2)
print("Right")
term.setCursorPos(1, y-3)
print("[Shift]")
term.setCursorPos(x/5*4, y-3)
print("C")
term.setCursorPos(3,y-2)
print("Up")
term.setCursorPos(x/5*4 - 1,y-2)
print("Set")
term.setCursorPos(1, y-1)
print("[Ctrl]")
term.setCursorPos(x/5*4-5, y-1)
print("Destination")
term.setCursorPos(2, y)
print("Down")
end

function waypoint() -- lets user set a waypoint to travel to
  term.clear()
  term.setCursorPos(1,1)
  write("Enter x coordinate of destination: ")
  xDest = io.read()
  xDest = tonumber(xDest)
  term.clear()
  term.setCursorPos(1,1)
  write("Enter y coordinate of destination: ")
  yDest = io.read()
  yDest = tonumber(yDest)
  term.clear()
  term.setCursorPos(1,1)
  write("Enter z coordinate of destination: ")
  zDest = io.read()
  zDest = tonumber(zDest)
  term.clear()
  term.setCursorPos(1,1)
  print("Traveling to "..xDest.." "..yDest.." "..zDest)
  if pos == "top" then
    topToBack()
  end
  if yPos < yDest then
    for i = 1, yDest - yPos do
      goUp()
    end
  elseif yPos > yDest then
    for i = 1, yPos - yDest do
      goDown()
    end
  end
  if xPos < xDest then
    if xDest - xPos < 0 then
      xDis = (xDest - xPos) * -1
    else
      xDis = xDest - xPos
    end
    for i = 1, xDis do
      goRight()
    end
  elseif xPos > xDest then
    if xPos - xDest < 0 then
      xDis = (xPos - xDest) * -1
    else
      xDis = xPos - xDest
    end
    for i = 1, xDis do
      goLeft()
    end
  end
  if zPos < zDest then
    if zPos - zDest < 0 then
      zDis = (zPos - zDest) * -1
    else
      --zDis = zDest - xPos
      zDis = zPos - zDest
    end
    if pos == "back" then
      backToTop()
    end
    for i = 1, zDis do
      goBack()
    end
  elseif zPos > zDest then
    if zDest - zPos < 0 then
      zDis = (zPos - zDest) * -1
    else
      zDis = zPos - zDest
    end
    for i = 1, xDis do
      goForward()
    end
  end
  display()
end


-- determine turtle position above or behind the engine
result = fs.exists("pos")
if result == true then
  file = io.open("pos", "r")
  pos = file.read()
  file:close()
else
  pos = "back"
  file = fs.open("pos", "w")
  file.write(pos)
  file:close()
end
if pos == "back" then
  eng = peripheral.wrap("front")
else
  eng = peripheral.wrap("bottom")
end


function coords()
  file = io.open("x", "r")
  xPos = file.read()
  xPos = tonumber(xPos)
  file:close()
  file = io.open("y", "r")
  yPos = file.read()
  yPos = tonumber(yPos)
  file:close()
  file = io.open("z", "r")
  zPos = file.read()
  zPos = tonumber(zPos)
  file:close()
end

result = fs.exists("x") --determine if turtle knows it's position
if result == true then
  file = io.open("x", "r")
  xPos = file.read()
  xPos = tonumber(xPos)
  file:close()
  file = io.open("y", "r")
  yPos = file.read()
  yPos = tonumber(yPos)
  file:close()
  file = io.open("z", "r")
  zPos = file.read()
  zPos = tonumber(zPos)
  file:close()
else
  term.clear()
  term.setCursorPos(1,1)
  write("Enter the Turtle's x coordinate: ")
  xPos = io.read()
  file = fs.open("x", "w")
  file.write(xPos)
  file:close()
  term.clear()
  xPos = tonumber(xPos)
  term.setCursorPos(1,1)
  write("Enter the Turtle's y coordinate: ")
  yPos = io.read()
  file = fs.open("y", "w")
  file.write(yPos)
  file:close()
  term.clear()
  yPos = tonumber(yPos)
  term.setCursorPos(1,1)
  write("Enter the Turtle's z coordinate: ")
  zPos = io.read()
  file = fs.open("z", "w")
  file.write(zPos)
  file:close()
  zPos = tonumber(zPos)
  term.clear()
  term.setCursorPos(1,1)
end

display()
while true do
  coords()
  timeout = os.startTimer(0.5)
  event, param = os.pullEvent()
  if event == "timer" then
    if con == "on" then
      if dir ~= 31 then
        if pos == "top" then
          topToBack()
        end
        if dir == 17 then
          goForward()
        elseif dir == 32 then
          goRight()
        elseif dir == 30 then
          goLeft()
        elseif dir == 42 then
          goUp()
        elseif dir == 29 then
          goDown()
        end
      elseif dir == 31 then
        dir = 31
        if pos == "back" then
          backToTop()
        end
        goBack()
      end
    end
  end
  if param ~= 31 and event == "key" then
    if pos == "top" then
      topToBack()
    end
    if param == 17 then
      goForward()
    elseif param == 32 then
      goRight()
    elseif param == 30 then
      goLeft()
    elseif param == 42 then
      goUp()
    elseif param == 29 then
      goDown()
    elseif param == 19 then
      if con == "on" then
         con = "off"
      else
         con = "on"
      end
      os.sleep(0.5)
      dir = nil
      term.setCursorPos(x/5*4, y/3-1)
      print(con.." ")
    elseif param == 46 then
      waypoint()
    end
  elseif param == 31 then
    dir = 31
    if pos == "back" then
      backToTop()
    end
    goBack()
  end
end