# SPDX-License-Identifier: Apache-2.0

# Copyright 2020 Contributors to OpenLEADR

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at

#     http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from datetime import datetime, timedelta, timezone
import warnings

def preflight_message(message_type, message_payload):
    """
    Tests message contents before sending them. It will correct benign errors
    and warn you about them. Uncorrectable errors will raise an Exception. It
    changes the message_payload dict in-place.

    :param message_type string: The type of message you are sending
    :param message_payload dict: The contents of the message
    """
    if f'_preflight_{message_type}' in globals():
        globals()[f'_preflight_{message_type}'](message_payload)
    return message_type, message_payload

def _preflight_oadrDistributeEvent(message_payload):
    if 'parse_duration' not in globals():
        from .utils import parse_duration
    # Check that the total event_duration matches the sum of the interval durations (rule 8)
    for event in message_payload['events']:
        active_period_duration = event['active_period']['duration']
        signal_durations = []
        for signal in event['event_signals']:
            signal_durations.append(sum([parse_duration(i['duration']) for i in signal['intervals']], timedelta(seconds=0)))

        if not all([d==active_period_duration for d in signal_durations]):
            if not all([d==signal_durations[0] for d in signal_durations]):
                raise ValueError("The different EventSignals have different total durations. Please correct this.")
            else:
                warnings.warn(f"The active_period duration for event {event['event_descriptor']['event_id']} ({active_period_duration})"
                              f" was different from the sum of the interval's durations ({signal_durations[0]})."
                              f" The active_period duration has been adjusted to ({signal_durations[0]}).")
                event['active_period']['duration'] = signal_durations[0]

    # Check that payload values with signal name SIMPLE are constricted (rule 9)
    for event in message_payload['events']:
        for event_signal in event['event_signals']:
            if event_signal['signal_name'] == "SIMPLE":
                for interval in event_signal['intervals']:
                    if interval['signal_payload'] not in (0, 1, 2, 3):
                        raise ValueError("Payload Values used with Signal Name SIMPLE must be one of"
                                         "0, 1, 2 or 3")

    # Check that the current_value is 0 for SIMPLE events that are not yet active (rule 14)
    for event in message_payload['events']:
        for event_signal in event['event_signals']:
            if 'current_value' in event_signal and event_signal['current_value'] != 0:
                if event_signal['signal_name'] == "SIMPLE" and event['event_descriptor']['event_status'] != "ACTIVE":
                    warnings.warn("The current_value for a SIMPLE event that is not yet active must be 0. This will be corrected.")
                    event_signal['current_value'] = 0

    # Check that there is a valid oadrResponseRequired value for each Event
    for event in message_payload['events']:
        if 'response_required' not in event:
            event['response_required'] = 'always'
        elif event['response_required'] not in ('never', 'always'):
            warnings.warn(f"The response_required property in an Event should be 'never' or 'always', not {event['response_required']}. Changing to 'always'.")
            event['response_required'] = 'always'

    # Check that there is a valid oadrResponseRequired value for each Event
    for event in message_payload['events']:
        if 'created_date_time' not in event['event_descriptor'] or not event['event_descriptor']['created_date_time']:
            print("ADDING CREATED DATE TIME")
            event['event_descriptor']['created_date_time'] = datetime.now(timezone.utc)