-- URL: https://pastebin.com/QbSGDWvG

-- Run this on startup:
-- Get the script: pastebin get QbSGDWvG turtle_server
-- edit startup
-- paste: shell.run("turtle_server")
-- Reboot to check it's working

-- Run update script on startup
print("=== Turtle Server Starting ===")
print("Running update script...")
shell.run("update")
print("Update complete. Starting turtle server...")

-- Mainframe communication
local MAINFRAME_ID = nil

-- Function to discover mainframe ID via broadcast
local function discoverMainframe()
  if MAINFRAME_ID then return MAINFRAME_ID end

  print("Broadcasting to discover mainframe...")
  rednet.broadcast("discover_mainframe")

  -- Wait for responses for up to 3 seconds
  local timeout = os.clock() + 3
  while os.clock() < timeout do
    local senderId, message = rednet.receive(0.1)
    if senderId and message == "mainframe_here" then
      MAINFRAME_ID = senderId
      print("Discovered mainframe at ID: " .. MAINFRAME_ID)
      return MAINFRAME_ID
    end
  end

  print("No mainframe found via broadcast")
  return nil
end

-- Function to report current GPS location to mainframe
local function reportLocationToMainframe()
  local mainframeId = discoverMainframe()
  if mainframeId then
    local gpsX, gpsY, gpsZ = gps.locate()
    if gpsX and gpsY and gpsZ then
      local message = {
        type = "location",
        x = gpsX,
        y = gpsY,
        z = gpsZ
      }
      rednet.send(mainframeId, message)
      print("Reported location to mainframe " .. mainframeId .. ": (" .. gpsX .. ", " .. gpsY .. ", " .. gpsZ .. ")")
    else
      print("Cannot report location - GPS not available")
    end
  else
    print("Cannot report location - mainframe not available")
  end
end

-- Function to open a modem on any side
local function openModem()
  local sides = {"left", "right", "top", "bottom", "front", "back"}
  for _, side in ipairs(sides) do
    if peripheral.getType(side) == "modem" then
      rednet.open(side)
      return true
    end
  end
  return false
end

-- Function to get the current GPS position
local function getCurrentPosition()
  local x, y, z = gps.locate(5)  -- Wait up to 5 seconds for a GPS fix
  if x and y and z then
    return {x = x, y = y, z = z}
  else
    print("Unable to determine GPS position.")
    return nil
  end
end

-- Function to determine the turtle's current heading
local function getHeading()
  local initialPos = getCurrentPosition()
  if not initialPos then return nil end

  -- Try moving forward to determine heading
  if turtle.forward() then
    local newPos = getCurrentPosition()
    turtle.back()  -- Return to original position

    if newPos.x > initialPos.x then
      return 1  -- East
    elseif newPos.x < initialPos.x then
      return 3  -- West
    elseif newPos.z > initialPos.z then
      return 2  -- South
    elseif newPos.z < initialPos.z then
      return 0  -- North
    end
  end

  -- If forward is blocked, try moving up
  if turtle.up() then
    turtle.down()  -- Return to original position
    return getHeading()  -- Retry after moving up
  end

  -- If all directions are blocked, return nil
  return nil
end

-- Function to face a specific direction
local function faceDirection(targetHeading)
  local currentHeading = getHeading()
  if currentHeading == nil then
    print("Unable to determine current heading.")
    return
  end

  local turns = (targetHeading - currentHeading) % 4
  if turns == 1 then
    turtle.turnRight()
  elseif turns == 2 then
    turtle.turnRight()
    turtle.turnRight()
  elseif turns == 3 then
    turtle.turnLeft()
  end
end

-- Function to move to a specific GPS location
local function goTo(x, y, z)
  local currentPos = getCurrentPosition()
  if not currentPos then
    print("Cannot move without GPS position.")
    return
  end

  -- Move vertically to the target y level first
  while currentPos.y < y do
    if not turtle.up() then turtle.digUp() end
    currentPos.y = currentPos.y + 1
    reportLocationToMainframe()
  end
  while currentPos.y > y do
    if not turtle.down() then turtle.digDown() end
    currentPos.y = currentPos.y - 1
    reportLocationToMainframe()
  end

  -- Move in the x direction
  if currentPos.x < x then
    faceDirection(1)  -- East
    while currentPos.x < x do
      if not turtle.forward() then turtle.dig() end
      currentPos.x = currentPos.x + 1
      reportLocationToMainframe()
    end
  elseif currentPos.x > x then
    faceDirection(3)  -- West
    while currentPos.x > x do
      if not turtle.forward() then turtle.dig() end
      currentPos.x = currentPos.x - 1
      reportLocationToMainframe()
    end
  end

  -- Move in the z direction
  if currentPos.z < z then
    faceDirection(2)  -- South
    while currentPos.z < z do
      if not turtle.forward() then turtle.dig() end
      currentPos.z = currentPos.z + 1
      reportLocationToMainframe()
    end
  elseif currentPos.z > z then
    faceDirection(0)  -- North
    while currentPos.z > z do
      if not turtle.forward() then turtle.dig() end
      currentPos.z = currentPos.z - 1
      reportLocationToMainframe()
    end
  end
end

-- Start the rednet server
local function startRednetServer()
  if not openModem() then
    print("No modem found. Please attach a modem to the turtle.")
    return
  end

  print("Rednet server started. Listening for commands...")

  -- Report initial location to mainframe
  reportLocationToMainframe()

  while true do
    local senderId, message = rednet.receive()
    print("Received command from " .. senderId .. ": " .. message)

    if message == "get location" then
      local pos = getCurrentPosition()
      if pos then
        -- Report current location to mainframe as well
        reportLocationToMainframe()
        rednet.send(senderId, "Current location: (" .. pos.x .. ", " .. pos.y .. ", " .. pos.z .. ")")
      else
        rednet.send(senderId, "Unable to determine GPS position.")
      end
    elseif message:match("^go to location") then
      local x, y, z = message:match("go to location ([%-]?%d+) ([%-]?%d+) ([%-]?%d+)")
      if x and y and z then
        rednet.send(senderId, "Moving to location: (" .. x .. ", " .. y .. ", " .. z .. ")")
        goTo(tonumber(x), tonumber(y), tonumber(z))
        rednet.send(senderId, "Arrived at location: (" .. x .. ", " .. y .. ", " .. z .. ")")
      else
        rednet.send(senderId, "Invalid location format. Use: go to location <x> <y> <z>")
      end
    end
  end
end

-- Run the server
startRednetServer()