"""Amazon Eventbridge Scheduler connector."""

import functools
import json

import boto3
import botocore


def get_scheduler_client():
    """Get Scheduler client.

    Returns:
        boto3.client.scheduler: scheduler client.
    """
    return boto3.client('scheduler')


def scheduler_client_wrap(func):
    """Wrap shared boto3 scheduler client.

    Creates a new client if one isn't passed in. Keeps it at one
    client per scheduler connector function call.
    """
    @functools.wraps(func)
    def wrapper(*args, **kwargs):
        client = kwargs.pop('client', None)
        if client:
            return func(*args, client=client, **kwargs)
        else:
            return func(*args, client=get_scheduler_client(), **kwargs)

    return wrapper


@scheduler_client_wrap
def get_event_schedule(schedule_name, scheduler_group, client=None):
    """Get scheduled event.

    Args:
        schedule_name (str or int): name of the schedule to get.

    Returns:
        dict with all schedule information or None.
    """
    try:
        return client.get_schedule(
            GroupName=scheduler_group,
            Name=f'{schedule_name}'
        )
    except botocore.exceptions.ClientError as error:
        if error.response['Error']['Code'] != 'ResourceNotFoundException':
            raise error


@scheduler_client_wrap
def create_event_schedule(
    schedule_name,
    schedule_datetime,
    target_arn,
    payload,
    scheduler_group,
    scheduler_role_arn,
    description='',
    client=None
):
    """Create scheduled event.

    Args:
        schedule_name (str or int): name of the schedule to create.
        schedule_datetime (str): datetime string to process event at.
        target_arn (str): arn of the schedules target.
        payload (dict): body to be sent to target.
        description (str): desciption of the schedule.

    Returns:
        dict: { ScheduledArn: string }
    """
    return client.create_schedule(
        Name=f'{schedule_name}',
        GroupName=scheduler_group,
        ScheduleExpression=f'at({schedule_datetime.replace("Z", "")})',
        ScheduleExpressionTimezone='Etc/UTC',
        Description=f'{description}',
        FlexibleTimeWindow={'Mode': 'OFF'},
        State='ENABLED',
        Target={
            'Arn': target_arn,
            'Input': json.dumps(payload),
            'RetryPolicy': {
                'MaximumEventAgeInSeconds': 300,
                'MaximumRetryAttempts': 3
            },
            'RoleArn': scheduler_role_arn,
        },
        ActionAfterCompletion='DELETE',
    )


@scheduler_client_wrap
def update_event_schedule(
    schedule_name,
    schedule_datetime,
    target_arn,
    payload,
    scheduler_group,
    scheduler_role_arn,
    description='',
    client=None
):
    """Update scheduled event.

    Args:
        schedule_name (str or int): name of the schedule to update.
        schedule_datetime (str): datetime string to process event at.
        target_arn (str): arn of the schedules target.
        payload (dict): body to be sent to target.
        description (str): desciption of the schedule.

    Returns:
        dict: { ScheduledArn: string }
    """
    return client.update_schedule(
        Name=f'{schedule_name}',
        GroupName=scheduler_group,
        ScheduleExpression=f'at({schedule_datetime.replace("Z", "")})',
        ScheduleExpressionTimezone='Etc/UTC',
        Description=f'{description}',
        FlexibleTimeWindow={'Mode': 'OFF'},
        State='ENABLED',
        Target={
            'Arn': target_arn,
            'Input': json.dumps(payload),
            'RetryPolicy': {
                'MaximumEventAgeInSeconds': 300,
                'MaximumRetryAttempts': 3
            },
            'RoleArn': scheduler_role_arn,
        },
        ActionAfterCompletion='DELETE',
    )


@scheduler_client_wrap
def upsert_event_schedule(
    schedule_name,
    schedule_datetime,
    target_arn,
    payload,
    scheduler_group,
    scheduler_role_arn,
    description='',
    client=None
):
    """Check if a schedule with the given name exists.

       If data exists, update the schedule.
       If data does not exist, create a new schedule.

    Args:
        schedule_name (str or int): name of the schedule to update.
        schedule_datetime (str): datetime string to process event at.
        target_arn (str): arn of the schedules target.
        input (dict): body to be sent to target.
        description (str): desciption of the schedule.

    Returns:
        dict: { ScheduledArn: string }
    """
    existing = get_event_schedule(
        schedule_name, scheduler_group, client=client)
    if existing:
        return update_event_schedule(
            schedule_name, schedule_datetime, target_arn, payload,
            scheduler_group, scheduler_role_arn, description, client=client)
    else:
        return create_event_schedule(
            schedule_name, schedule_datetime, target_arn, payload,
            scheduler_group, scheduler_role_arn, description, client=client)


@scheduler_client_wrap
def delete_event_schedule(
        schedule_name, scheduler_group, client=None):
    """Delete scheduled event.

    Args:
        schedule_name (str or int): name of the schedule to delete.

    Returns:
        Empty dict or None.
    """
    try:
        return client.delete_schedule(
            GroupName=scheduler_group,
            Name=f'{schedule_name}'
        )
    except botocore.exceptions.ClientError as error:
        if error.response['Error']['Code'] != 'ResourceNotFoundException':
            raise error