#  Copyright © 2023 Ingram Micro Inc. All rights reserved.

import logging
from inspect import getfullargspec, isfunction

from django.utils.module_loading import import_string

from dj_cqrs.constants import (
    DEFAULT_MASTER_AUTO_UPDATE_FIELDS,
    DEFAULT_MASTER_MESSAGE_TTL,
    DEFAULT_REPLICA_DELAY_QUEUE_MAX_SIZE,
    DEFAULT_REPLICA_MAX_RETRIES,
    DEFAULT_REPLICA_RETRY_DELAY,
)
from dj_cqrs.registries import MasterRegistry, ReplicaRegistry
from dj_cqrs.transport import BaseTransport


logger = logging.getLogger('django-cqrs')


def validate_settings(settings):
    is_master = bool(MasterRegistry.models)
    is_replica = bool(ReplicaRegistry.models)
    if (not is_master) and (not is_replica):  # pragma: no cover
        return

    assert hasattr(settings, 'CQRS'), 'CQRS configuration must be set in Django project settings.'

    cqrs_settings = settings.CQRS
    assert isinstance(cqrs_settings, dict), 'CQRS configuration must be dict.'

    _validate_transport(cqrs_settings)

    if is_master or ('master' in cqrs_settings):
        _validate_master(cqrs_settings)

    if is_replica or ('replica' in cqrs_settings):
        _validate_replica(cqrs_settings)


def _validate_transport(cqrs_settings):
    transport_cls_location = cqrs_settings.get('transport')
    if not transport_cls_location:
        raise AssertionError('CQRS transport is not set.')

    transport = import_string(transport_cls_location)
    if not issubclass(transport, BaseTransport):
        raise AssertionError(
            'CQRS transport must be inherited from `dj_cqrs.transport.BaseTransport`.',
        )


def _validate_master(cqrs_settings):
    default_master_settings = {
        'master': {
            'CQRS_AUTO_UPDATE_FIELDS': DEFAULT_MASTER_AUTO_UPDATE_FIELDS,
            'CQRS_MESSAGE_TTL': DEFAULT_MASTER_MESSAGE_TTL,
            'correlation_function': None,
            'meta_function': None,
        },
    }

    if 'master' not in cqrs_settings:
        cqrs_settings.update(default_master_settings)
        return

    master_settings = cqrs_settings['master']
    assert isinstance(master_settings, dict), 'CQRS master configuration must be dict.'

    _validate_master_auto_update_fields(master_settings)
    _validate_master_message_ttl(master_settings)
    _validate_master_correlation_func(master_settings)
    _validate_master_meta_func(master_settings)


def _validate_master_auto_update_fields(master_settings):
    if 'CQRS_AUTO_UPDATE_FIELDS' in master_settings:
        assert isinstance(
            master_settings['CQRS_AUTO_UPDATE_FIELDS'],
            bool,
        ), 'CQRS master CQRS_AUTO_UPDATE_FIELDS must be bool.'
    else:
        master_settings['CQRS_AUTO_UPDATE_FIELDS'] = DEFAULT_MASTER_AUTO_UPDATE_FIELDS


def _validate_master_message_ttl(master_settings):
    if 'CQRS_MESSAGE_TTL' in master_settings:
        min_message_ttl = 1
        message_ttl = master_settings['CQRS_MESSAGE_TTL']
        if (message_ttl is not None) and (
            not isinstance(message_ttl, int) or message_ttl < min_message_ttl
        ):
            # No error is raised for backward compatibility
            # TODO: raise error in 2.0.0
            logger.warning(
                'Settings CQRS_MESSAGE_TTL=%s is invalid, using default %s.',
                message_ttl,
                DEFAULT_MASTER_MESSAGE_TTL,
            )
            master_settings['CQRS_MESSAGE_TTL'] = DEFAULT_MASTER_MESSAGE_TTL
    else:
        master_settings['CQRS_MESSAGE_TTL'] = DEFAULT_MASTER_MESSAGE_TTL


def _validate_master_correlation_func(master_settings):
    correlation_func = master_settings.get('correlation_function')
    if not correlation_func:
        master_settings['correlation_function'] = None
    elif not callable(correlation_func):
        raise AssertionError('CQRS master correlation_function must be callable.')


def _validate_master_meta_func(master_settings):
    meta_func = master_settings.get('meta_function')
    if not meta_func:
        master_settings['meta_function'] = None
        return

    if isinstance(meta_func, str):
        try:
            meta_func = import_string(meta_func)
        except ImportError:
            raise AssertionError('CQRS master meta_function import error.')

    if not isfunction(meta_func):
        raise AssertionError('CQRS master meta_function must be function.')

    r = getfullargspec(meta_func)
    if not r.varkw:
        raise AssertionError('CQRS master meta_function must support **kwargs.')

    master_settings['meta_function'] = meta_func


def _validate_replica(cqrs_settings):
    queue = cqrs_settings.get('queue')
    assert queue, 'CQRS queue is not set.'
    assert isinstance(queue, str), 'CQRS queue must be string.'

    default_replica_settings = {
        'replica': {
            'CQRS_MAX_RETRIES': DEFAULT_REPLICA_MAX_RETRIES,
            'CQRS_RETRY_DELAY': DEFAULT_REPLICA_RETRY_DELAY,
            'delay_queue_max_size': DEFAULT_REPLICA_DELAY_QUEUE_MAX_SIZE,
        },
    }

    if 'replica' not in cqrs_settings:
        cqrs_settings.update(default_replica_settings)
        return

    replica_settings = cqrs_settings['replica']
    assert isinstance(replica_settings, dict), 'CQRS replica configuration must be dict.'

    _validate_replica_max_retries(replica_settings)
    _validate_replica_retry_delay(replica_settings)
    _validate_replica_delay_queue_max_size(replica_settings)


def _validate_replica_max_retries(replica_settings):
    if 'CQRS_MAX_RETRIES' in replica_settings:
        min_retries = 0
        max_retries = replica_settings['CQRS_MAX_RETRIES']
        if (max_retries is not None) and (
            not isinstance(max_retries, int) or max_retries < min_retries
        ):
            # No error is raised for backward compatibility
            # TODO: raise error in 2.0.0
            logger.warning(
                'Replica setting CQRS_MAX_RETRIES=%s is invalid, using default %s.',
                max_retries,
                DEFAULT_REPLICA_MAX_RETRIES,
            )
            replica_settings['CQRS_MAX_RETRIES'] = DEFAULT_REPLICA_MAX_RETRIES
    else:
        replica_settings['CQRS_MAX_RETRIES'] = DEFAULT_REPLICA_MAX_RETRIES


def _validate_replica_retry_delay(replica_settings):
    min_retry_delay = 0
    retry_delay = replica_settings.get('CQRS_RETRY_DELAY')
    if 'CQRS_RETRY_DELAY' not in replica_settings:
        replica_settings['CQRS_RETRY_DELAY'] = DEFAULT_REPLICA_RETRY_DELAY
    elif not isinstance(retry_delay, int) or retry_delay < min_retry_delay:
        # No error is raised for backward compatibility
        # TODO: raise error in 2.0.0
        logger.warning(
            'Replica setting CQRS_RETRY_DELAY=%s is invalid, using default %s.',
            retry_delay,
            DEFAULT_REPLICA_RETRY_DELAY,
        )
        replica_settings['CQRS_RETRY_DELAY'] = DEFAULT_REPLICA_RETRY_DELAY


def _validate_replica_delay_queue_max_size(replica_settings):
    min_qsize = 0
    max_qsize = replica_settings.get('delay_queue_max_size')
    if 'delay_queue_max_size' not in replica_settings:
        max_qsize = DEFAULT_REPLICA_DELAY_QUEUE_MAX_SIZE
    elif (max_qsize is not None) and (not isinstance(max_qsize, int) or max_qsize <= min_qsize):
        # No error is raised for backward compatibility
        # TODO: raise error in 2.0.0
        logger.warning(
            'Settings delay_queue_max_size=%s is invalid, using default %s.',
            max_qsize,
            DEFAULT_REPLICA_DELAY_QUEUE_MAX_SIZE,
        )
        max_qsize = DEFAULT_REPLICA_DELAY_QUEUE_MAX_SIZE

    replica_settings['delay_queue_max_size'] = max_qsize