WIP

src/dm_mac/machine_state.py

@@ -0,0 +1,73 @@
+"""Classes and functions related to machine state."""
+from typing import Optional
+from logging import getLogger, Logger
+from time import time
+
+
+logger: Logger = getLogger(__name__)
+
+DEFAULT_DISPLAY_TEXT: str = 'Please Insert\nRFID Card'
+
+
+class MachineState:
+    """Object representing frozen state in time of a machine."""
+
+    def __init__(self, machine_name: str):
+        """Initialize a new MachineState instance."""
+        logger.debug('Instantiating new MachineState for %s', machine_name)
+        #: The name of the machine
+        self.name: str = machine_name
+        #: Float timestamp of the machine's last checkin time
+        self.last_checkin: Optional[float] = None
+        #: Float timestamp of the last time that machine state changed,
+        #: not counting `current_amps` or timestamps.
+        self.last_update: Optional[float] = None
+        #: Value of the RFID card/fob in use, or None if not present.
+        self.rfid_value: Optional[str] = None
+        #: Float timestamp when `rfid_value` last changed to a non-None value.
+        self.rfid_present_since: Optional[float] = None
+        #: Whether the output relay is on or not.
+        self.relay_is_on: bool = False
+        #: Whether the output relay should be on or not.
+        self.relay_desired_state: bool = False
+        #: Whether the machine's Oops button has been pressed.
+        self.is_oopsed: bool = False
+        #: Whether the machine is locked out from use.
+        self.is_locked_out: bool = False
+        #: Whether the machine is force-enabled without RFID present.
+        self.is_force_enabled: bool = False
+        #: Last reported output ammeter reading (if equipped).
+        self.current_amps: float = 0
+        #: Text currently displayed on the machine LCD screen
+        self.display_text: str = DEFAULT_DISPLAY_TEXT
+        self._load_from_cache()
+
+    def _save_cache(self):
+        """Save machine state cache to disk."""
+        raise NotImplementedError()
+
+    def update_has_changes(
+        self, rfid_value: str, relay_state: bool, oops: bool, amps: float
+    ) -> bool:
+        """Return whether or not the update causes changes to significant state values."""
+        if (
+            rfid_value != self.rfid_value or
+            relay_state != self.relay_is_on or
+            oops != self.is_oopsed
+        ):
+            return True
+        return False
+
+    def noop_update(self, amps: float):
+        """Just update amps and last_checkin and save cache."""
+        self.current_amps = amps
+        self.last_checkin = time()
+        self._save_cache()
+
+    @property
+    def machine_response(self) -> dict:
+        """Return the response dict to send to the machine."""
+        return {
+            'relay': self.relay_desired_state,
+            'display': self.display_text
+        }

src/dm_mac/views/machine.py

@@ -0,0 +1,30 @@
+"""Views related to machine endpoints."""
+from typing import Any, Dict
+from flask import Blueprint, request, app
+
+
+machine: Blueprint = Blueprint("machine", __name__, url_prefix="/machine")
+
+
+@machine.route("/update", methods=['POST'])
+def update():
+    """
+    API method to update machine state.
+
+    Accepts POSTed JSON containing the following key/value pairs:
+
+    - "name" (string) - name of the machine sending the update
+    - "rfid_value" (string) - value of the RFID fob/card that is currently
+        present in the machine, or empty string if none present
+    - "relay_state" (boolean) - the current on/off (true/false) state of the
+        relay
+    - "oops" (boolean) - whether the oops button is pressed, or has been pressed
+        since the last check-in
+    - "amps" (float) - amperage value from the current clamp ammeter, if present,
+        or 0.0 otherwise.
+    """
+    data: Dict[str, Any] = request.json
+    machine_name: str = data.pop('name')
+    # get the MachineState object for this machine, or else return an error
+    #    that error should be formatted for display on the device (helper method for this)
+    # check if this data would update the state; if not, just call noop_update() and return the same display value