#This compares the datetime objects without timezones

#do something with time with both datetime and pendulum

#dags can do same thing

#give it a start date in the past

# proposed test plan:
# dag1:
#  - pendulum start time in the past
#  - standard datetime in the future as a user macro
#  - task that calculates the difference between the two and prints it
# dag2:
#  - standard start time in the past
#  - pendulum datetime in the future as a user macro
#  - task that calculates the difference between the two and prints it
# (future) outer dag:
# - run both and compare that they do the same things

#templated fields to calculate how long ago the start date is
from airflow.models.dag import DAG
from airflow.providers.standard.operators.python import PythonOperator
from airflow.operators.empty import EmptyOperator

#from pendulum import datetime, timezone
import pendulum
import datetime
import pytz


etc_gmt13 = 'Etc/GMT-13'

chuuk = 'Pacific/Chuuk'

#start_date = pendulum.datetime(2021, 11, 25)
#start_date = pendulum.datetime(2135, 11, 25)
start_date = datetime.datetime(2021, 11, 25)

def subtractor(start_date, future_date):
    print(type(start_date), type(future_date)) #both strings, now find a way to compare
    if "T" in start_date or "T" in future_date:
        start_date = start_date.replace("T", "")
        future_date = future_date.replace("T", "")
    if "00:00:00" in start_date or "00:00:00" in future_date:
        start_date = start_date.replace("00:00:00", "")
        future_date = future_date.replace("00:00:00", "")
    
    if "+00:00" in start_date or "+00:00" in future_date:
        start_date = start_date.replace("+00:00", "")
        future_date = future_date.replace("+00:00", "")

    print(start_date, future_date) #2021-11-25 00:00:00+10:00 2135-11-25 00:00:00+13:00

    for i in start_date:
        if "-"==i:
            start_date = start_date.replace("-", "_")
    
    for i in future_date:
        if "-"==i:
            future_date = future_date.replace("-", "_")

    print(f"The newly filtered start date is {start_date} and the newly filtered future date is {future_date}") 
    #2021_11_25 +10:00, 2135_11_25 +13:00
    start_date_obj = datetime.datetime.strptime(start_date.strip(), "%Y_%m_%d")
    future_date_obj = datetime.datetime.strptime(future_date.strip(), "%Y_%m_%d")
    print(f"The start date object is: {start_date_obj}")
    print(f"The future date object is: {future_date_obj}")
    #now that the filtering has commenced
    #compare the 2 datetimes to ensure the result is the same across the 2 dags
    #the actual comparison

    the_difference = future_date_obj - start_date_obj
    print(f"This is the difference between the 2 dates in days: {the_difference}")
    print(f"This is the datatype of the difference betweeen the  2 datetime objects: {type(the_difference)}")


default_args = {
    "owner": "airflow",
}

with DAG(
    dag_id="compare_pendulum_datetime2",
    default_args=default_args,
    #datetime start date, pendulum future date as user defined macro
    start_date=start_date,
    schedule=None,
    catchup=False,
    user_defined_macros={
        "future_date": pendulum.datetime(2135, 11, 25)
    },
    tags=['core'],
) as dag:

    t1 = PythonOperator(
        task_id="subtract_future_and_start_date",
        python_callable=subtractor,
        op_args=[str(start_date), '{{ future_date }}']
    )

t1