feat(robot): add saveRobotState and loadRobotState methods

README.md

@@ -30,7 +30,9 @@ upgrade
 
 ```
 rm config
+rm data
 rm startup.lua
 rm .minerstate
+rm .robotstate
 upgrade
 ```

libs/robot.lua

@@ -2,6 +2,8 @@
 
 local api = {}
 
+local ROBOT_DEFAULT_STATE_FILE = '/.robotstate'
+
 local function createDefaultState()
   return {
     y = 0,
@@ -12,7 +14,8 @@ local function createDefaultState()
   }
 end
 
-api.create = function(state)
+api.create = function(state, defaultStateFile)
+  defaultStateFile = defaultStateFile or ROBOT_DEFAULT_STATE_FILE
   state = state or createDefaultState()
 
   local mutateRobotPosition = function(isBackward)
@@ -113,6 +116,40 @@ api.create = function(state)
     return state
   end
 
+  robot.saveRobotState = function(stateFile)
+    stateFile = stateFile or defaultStateFile
+    local file = fs.open(stateFile, 'w')
+
+    if not file then
+      error('saveRobotState: cannot open ' .. stateFile ..  ' file!')
+    end
+
+    file.write(textutils.serializeJSON(state))
+    file.close()
+
+    return state
+  end
+
+  robot.loadRobotState = function(stateFile)
+    stateFile = stateFile or defaultStateFile
+    local file = fs.open(stateFile, 'r')
+
+    if not file then
+      return robot.saveRobotState(stateFile)
+    end
+
+    local serializedRobotState = file.readAll()
+    file.close()
+
+    local parsedResult = textutils.unserializeJSON(serializedRobotState)
+
+    if not parsedResult then
+      return robot.saveRobotState(stateFile)
+    end
+
+    return parsedResult
+  end
+
   return robot
 end