import json
import time
from datadog_lambda.metric import lambda_metric
from ddtrace import tracer

def lambda_handler(event, context):
  current_span = tracer.current_span()
  if current_span:
    current_span.set_tag('owner', 'dpinchukov')

  with tracer.trace("dd-lambda-python.checkout"):
    log_event(event)
    get_cart_items()
    get_items_price()
    process_payment()

  return event

@tracer.wrap()
def log_event(event):
  print('Received event: ' + json.dumps(event, indent=2))

@tracer.wrap()
def get_cart_items():
  print("Getting cart items...")
  time.sleep(0.050)
  print("Got cart items.")
  lambda_metric(
    metric_name='dd-lambda-python.checkout.cart_items_amount',
    value=42,
    timestamp=int(time.time()),
    tags=['owner:dpinchukov']
  )

@tracer.wrap()
def get_items_price():
  print("Getting items price...")
  time.sleep(0.075)
  print("Got items price.")

@tracer.wrap()
def process_payment():
  print("Processing payment...")
  time.sleep(0.025)
  apply_coupon()
  print("Payment successfull.")

@tracer.wrap()
def apply_coupon():
  print("Applying coupon...")
  time.sleep(0.010)
  print("No coupon specified.")
  lambda_metric(
    metric_name='dd-lambda-python.checkout.coupon_applied',
    value=0,
    timestamp=int(time.time()),
    tags=['owner:dpinchukov']
  )