import itertools
from datetime import (datetime)

from flask import current_app
from monotonic import monotonic
from notifications_utils.recipients import (
    RecipientCSV,
    allowed_to_send_to
)
from notifications_utils.template import Template
from sqlalchemy.exc import SQLAlchemyError

from app import (
    create_uuid,
    DATETIME_FORMAT,
    DATE_FORMAT,
    notify_celery,
    encryption
)
from app.aws import s3
from app.celery.provider_tasks import send_sms_to_provider, send_email_to_provider
from app.dao.jobs_dao import (
    dao_update_job,
    dao_get_job_by_id
)
from app.dao.notifications_dao import (
    dao_create_notification,
    dao_get_notification_statistics_for_service_and_day
)
from app.dao.services_dao import dao_fetch_service_by_id
from app.dao.templates_dao import dao_get_template_by_id
from app.models import (
    Notification,
    EMAIL_TYPE,
    SMS_TYPE,
    KEY_TYPE_NORMAL
)
from app.statsd_decorators import statsd


@notify_celery.task(name="process-job")
@statsd(namespace="tasks")
def process_job(job_id):
    start = datetime.utcnow()
    job = dao_get_job_by_id(job_id)

    service = job.service

    stats = dao_get_notification_statistics_for_service_and_day(
        service_id=service.id,
        day=job.created_at.strftime(DATE_FORMAT)
    )

    total_sent = 0
    if stats:
        total_sent = stats.emails_requested + stats.sms_requested

    if total_sent + job.notification_count > service.message_limit:
        job.status = 'sending limits exceeded'
        job.processing_finished = datetime.utcnow()
        dao_update_job(job)
        current_app.logger.info(
            "Job {} size {} error. Sending limits {} exceeded".format(
                job_id, job.notification_count, service.message_limit)
        )
        return

    job.status = 'in progress'
    dao_update_job(job)

    template = Template(
        dao_get_template_by_id(job.template_id, job.template_version).__dict__
    )

    for row_number, recipient, personalisation in RecipientCSV(
            s3.get_job_from_s3(str(service.id), str(job_id)),
            template_type=template.template_type,
            placeholders=template.placeholders
    ).enumerated_recipients_and_personalisation:

        encrypted = encryption.encrypt({
            'template': str(template.id),
            'template_version': job.template_version,
            'job': str(job.id),
            'to': recipient,
            'row_number': row_number,
            'personalisation': {
                key: personalisation.get(key)
                for key in template.placeholders
                }
        })

        if template.template_type == SMS_TYPE:
            send_sms.apply_async((
                str(job.service_id),
                create_uuid(),
                encrypted,
                datetime.utcnow().strftime(DATETIME_FORMAT)),
                queue='bulk-sms'
            )

        if template.template_type == EMAIL_TYPE:
            send_email.apply_async((
                str(job.service_id),
                create_uuid(),
                encrypted,
                datetime.utcnow().strftime(DATETIME_FORMAT)),
                queue='bulk-email')

    finished = datetime.utcnow()
    job.status = 'finished'
    job.processing_started = start
    job.processing_finished = finished
    dao_update_job(job)
    remove_job.apply_async((str(job_id),), queue='remove-job')
    current_app.logger.info(
        "Job {} created at {} started at {} finished at {}".format(job_id, job.created_at, start, finished)
    )


@notify_celery.task(name="remove-job")
@statsd(namespace="tasks")
def remove_job(job_id):
    job = dao_get_job_by_id(job_id)
    s3.remove_job_from_s3(job.service.id, str(job_id))
    current_app.logger.info("Job {} has been removed from s3.".format(job_id))


@notify_celery.task(bind=True, name="send-sms", max_retries=5, default_retry_delay=300)
@statsd(namespace="tasks")
def send_sms(self,
             service_id,
             notification_id,
             encrypted_notification,
             created_at,
             api_key_id=None,
             key_type=KEY_TYPE_NORMAL):
    notification = encryption.decrypt(encrypted_notification)
    service = dao_fetch_service_by_id(service_id)

    if not service_allowed_to_send_to(notification['to'], service):
        current_app.logger.info(
            "SMS {} failed as restricted service".format(notification_id)
        )
        return

    try:
        _save_notification(created_at, notification, notification_id, service_id, SMS_TYPE, api_key_id, key_type)

        send_sms_to_provider.apply_async((service_id, notification_id), queue='sms')

        current_app.logger.info(
            "SMS {} created at {}".format(notification_id, created_at)
        )

    except SQLAlchemyError as e:
        current_app.logger.exception(e)
        raise self.retry(queue="retry", exc=e)


@notify_celery.task(bind=True, name="send-email", max_retries=5, default_retry_delay=300)
@statsd(namespace="tasks")
def send_email(self, service_id,
               notification_id,
               encrypted_notification,
               created_at,
               api_key_id=None,
               key_type=KEY_TYPE_NORMAL):
    notification = encryption.decrypt(encrypted_notification)
    service = dao_fetch_service_by_id(service_id)

    if not service_allowed_to_send_to(notification['to'], service):
        current_app.logger.info("Email {} failed as restricted service".format(notification_id))
        return

    try:
        _save_notification(created_at, notification, notification_id, service_id, EMAIL_TYPE, api_key_id, key_type)

        send_email_to_provider.apply_async((service_id, notification_id), queue='email')

        current_app.logger.info("Email {} created at {}".format(notification_id, created_at))
    except SQLAlchemyError as e:
        current_app.logger.exception(e)
        raise self.retry(queue="retry", exc=e)


def _save_notification(created_at, notification, notification_id, service_id, notification_type, api_key_id, key_type):
    notification_db_object = Notification(
        id=notification_id,
        template_id=notification['template'],
        template_version=notification['template_version'],
        to=notification['to'],
        service_id=service_id,
        job_id=notification.get('job', None),
        job_row_number=notification.get('row_number', None),
        status='created',
        created_at=datetime.strptime(created_at, DATETIME_FORMAT),
        personalisation=notification.get('personalisation'),
        notification_type=notification_type,
        api_key_id=api_key_id,
        key_type=key_type
    )
    dao_create_notification(notification_db_object, notification_type)


def service_allowed_to_send_to(recipient, service):
    if not service.restricted:
        return True

    return allowed_to_send_to(
        recipient,
        itertools.chain.from_iterable(
            [user.mobile_number, user.email_address] for user in service.users
        )
    )