"""
This example python code shows how to appropriately query the Preteckt
accelerometer API for data over a date range.


Run with:

    $ python get_accel_data.py


NOTE: Running this code in python3 is recommended.

"""
import requests  # Requires the requets package: pip install requests
from datetime import datetime, timedelta
from time import sleep


# See: https://dash.preteckt.us/accounts/
API_KEY = 'ADD-YOUR-API-KEY-HERE'

# The preteckt unit number whose data you want. Your account must have
# permission to view data for this unit.
UNIT = 247

# The total time period for data of interest.
START = '2018-09-01T00:00:00'
END = '2018-10-31T23:59:59'

# Request 3 days worth of data at a time.
CHUNK = 3

# The accelerometer API endpoint.
URL = 'https://dash.preteckt.us/api/rtdv/accelerometer/'


def get(unit, start, end, chunk):
    # Convert our start/end times to datetime objects.
    date_format = '%Y-%m-%dT%H:%M:%S'   # string format for all datetimes
    start = datetime.strptime(start, date_format)
    end = datetime.strptime(end, date_format)

    # In order to log in, we need to set an authorization header for
    # every HTTP request.
    headers = {'Authorization': "Token {}".format(API_KEY)}

    # Fetch our data chunk days at a time.
    while start <= end:
        td = timedelta(days=chunk)  # a time window of size "chunk" days.
        payload = {
            'unit_number': unit,
            'from_time': start.strftime(date_format),
            'to_time': (start + td).strftime(date_format),
        }
        resp = requests.get(URL, params=payload, headers=headers)
        data = resp.json()
        if resp.status_code == 200:
            # This example prints the response payload, but you could
            # alter this to write the data to a file.
            print(data)

            # Add a chunk of time to the starting
            start = start + td
        else:
            print("Unable to fetch data. Status: {}".format(resp.status_code))
            print(data)
            start = start + timedelta(days=365 * 9000)
        sleep(1)  # sleep 1 second just to be kind to the api.


if __name__ == "__main__":
    get(UNIT, START, END, CHUNK)