python-backend/index.py

import firebase_admin
from firebase_admin import credentials
from firebase_admin import firestore
from PIL import Image
import time
import os
import urllib.request

import camera
import image_tools
import config

config.bootstrap()

# Use a service account
cred = credentials.Certificate(os.getenv('FIREBASE_CERT_FILE'))
firebase_admin.initialize_app(cred)

db = firestore.client()

def poll():
    doc_ref_lot = db.collection('lots').document(os.getenv('LOT_NAME'))

    # Get the reference image
    lot_info = doc_ref_lot.collection('info').document('lotInfo').get().to_dict()
    urllib.request.urlretrieve('http://localhost:8000/img/references/'+lot_info['refImage'], './ref-img.jpg')
    reference = Image.open('./ref-img.jpg').load()

    # Take the picture
    img = Image.open(camera.capture(os.getenv('CAMERA_DEVICE'))).load()
    #img = Image.open('./lib/test-images-vert/lot-3-cars.jpg').load()

    doc_ref_stalls = doc_ref_lot.collection('stalls').get()

    for stall in doc_ref_stalls:
        stall_obj = stall.to_dict()
        color_reference = image_tools.average_color(stall_obj['locationX'], stall_obj['locationY'], stall_obj['width'], stall_obj['height'], reference)
        color_compare = image_tools.average_color(stall_obj['locationX'], stall_obj['locationY'], stall_obj['width'], stall_obj['height'], img)
        stall_occupied = image_tools.threshold(image_tools.differences(color_reference, color_compare), float(os.getenv('E_HAT_TRIGGER_LEVEL')))
        stall_obj['open'] = not stall_occupied
        print("Updated: "+stall.id)

        doc_ref_lot.collection('stalls').document(stall.id).set(stall_obj)


start_time = time.time()

while True:
    poll()
    poll_time = float(os.getenv('POLL_FREQUENCY'))
    time.sleep(poll_time - ((time.time() - start_time) % poll_time))