ComputerCraft lzTurtle API

--[[
/**
 * lzTurtle API
 *
 * Guaranteed movement functions for Turtles
 *
 * @copyright (C) LayZee 2014
 */
--]]

--[[ Local variables ]]--
local VERSION = 0.2

--[[ Local functions ]]--

--[[
/**
 * Verify that direction is supported in movement module
 *
 * @param string direction Direction to verify
 */
--]]
local verify = function(direction)
  local valid = {
    up = true,
    down = true,
    forward = true,
    back = true
  }

  assert(
    valid[direction],
    'Invalid direction \''
      .. direction
      .. '\' passed to function move'
  )
end

--[[
/**
 * Get move function
 *
 * @param string direction Direction to move
 */
--]]
local getMoveCallback = function(direction)
  local callback = {
    up = turtle.up,
    down = turtle.down,
    forward = turtle.forward,
    back = turtle.back
  }

  return callback[direction] or false
end

--[[
/**
 * Get detect function
 *
 * @param string direction Direction to detect
 */
--]]
local getDetectCallback = function(direction)
  local callback = {
    up = turtle.detectUp,
    down = turtle.detectDown,
    forward = turtle.detect
  }

  return callback[direction] or false
end

--[[
/**
 * Get dig function
 *
 * @param string direction Direction to dig
 */
--]]
local getDigCallback = function(direction)
  local callback = {
    up = turtle.digUp,
    down = turtle.digDown,
    forward = turtle.dig
  }

  return callback[direction] or false
end

--Define variable first to allow recursion
local move
--[[
/**
 * Move turtle one step
 *
 * @param string direction Direction to move
 */
--]]
move = function(direction)
  verify(direction)

  local moving = getMoveCallback(direction)
  local detect = getDetectCallback(direction)
  local dig = getDigCallback(direction)
  local isSeeded = false
  local turtleId = os.getComputerID()

  --Determine which side to check for adjacent CC peripherals
  local sideToCheckForPeripherals = 'front' --Default

  if direction == 'up' then
    sideToCheckForPeripherals = 'top'
  elseif direction == 'down' then
    sideToCheckForPeripherals = 'bottom'
  end

  --Try to move
  while not moving() do
    local peripheralType = peripheral.getType(sideToCheckForPeripherals)

    --Handle CC peripherals (turtle, cable, monitors, etc.)
    while peripheralType do
      if peripheralType == 'turtle' then
        --Seed randomizer
        isSeeded = isSeeded or math.randomseed(turtleId) and true

        local waitingPeriod = math.random(1, 10)

        --Move up, wait for 1 to 10 seconds, then move back down
        move('up')
        sleep(waitingPeriod)
        move('down')
      else
        --TODO: Handle other peripherals appropriately
        break
      end

      peripheralType = peripheral.getType(sideToCheckForPeripherals)
    end

    --Check if a block is in the way
    if detect() then
      if not dig() then
        error('Unbreakable block detected')
      elseif detect() then
        --Sand/gravel falling
        sleep(0.8)
      else
        --Block broken
      end
    elseif turtle.getFuelLevel()
      ~= 'unlimited'
      and turtle.getFuelLevel() == 0
    then
      error('No more fuel')
    elseif turtle.attack() then
      --Attacking NPC/player
    end
  end
end

--[[ Module definition ]]--
local module = {}

module.VERSION = VERSION

--[[
/**
 * Move turtle up n times
 *
 * @param int n Number of moves
 */
--]]
module.up = function(n)
  for i = 0, n - 1 do
    move('up')
  end
end

--[[
/**
 * Move turtle down n times
 *
 * @param int n Number of moves
 */
--]]
module.down = function(n)
  for i = 0, n - 1 do
    move('down')
  end
end

--[[
/**
 * Move turtle forward n times
 *
 * @param int n Number of moves
 */
--]]
module.forward = function(n)
  for i = 0, n - 1 do
    move('forward')
  end
end

--[[ Aliases ]]
module.u = function(n)
  module.up(n)
end

module.d = function(n)
  module.down(n)
end

module.f = function(n)
  module.forward(n)
end

return module