#! /usr/bin/env python
"""Helper script to launch a feed sender workflow for multiple days."""

import argparse
import datetime
import json
import subprocess


# for mocking in unit tests
log = print


def exec_multiple_days(flow, days, skip, dry_run=False):
    """Execute SWF Sender Flow for range of days.

    Will execute a workflow for last N days. The parameters describe the slice
    of days going backwards from today. So if skip=1 and days=5, it skips today
    and works on the 5 days before that.

    Args:
        flow (str): Name of flow.
        days (int): Number of past days to run workflow for.
        skip (int): Number of past days to skip starting from today.
        dry_run (bool): Output command statements without running.
    """
    # since days can include current day, subtract 1 in the offset. This
    # prevents offsets from always being at least one day back.
    days_offset = datetime.timedelta(days=days - 1)
    skip_offset = datetime.timedelta(days=skip)

    date_N_days_ago = datetime.date.today()
    date_N_days_ago -= days_offset
    date_N_days_ago -= skip_offset

    for i in range(days):
        context_date = date_N_days_ago + datetime.timedelta(days=i)
        context = {
            'context_date': context_date.strftime('%Y-%m-%d')}

        if dry_run:
            context_string = "'{context}'".format(  # noqa
                context=json.dumps(context))
            call = ['garcon', 'exec', flow, '--context', context_string]
            log(' '.join(call))
        else:
            context_string = '{context}'.format(context=json.dumps(context))
            call = ['garcon', 'exec', flow, '--context', context_string]
            subprocess.call(call)


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='Date Range Flow Exec')

    parser.add_argument('flow', help='name of the workflow')
    parser.add_argument(
        '--days', type=int, default=5,
        help=(
            'number of days to sync in the db from the start date defined by '
            'the skip flag (Default: 5)'))
    parser.add_argument(
        '--skip', type=int, default=1,
        help=(
            'number of days backwards from today to skip in the sync '
            '(Default: 1)'))
    parser.add_argument(
        '--dry-run', action='store_true',
        help='Output the calls without running them')

    args = parser.parse_args()

    exec_multiple_days(args.flow, args.days, args.skip, args.dry_run)