"""
This module controls defines celery tasks and their applicable schedules. The celery beat server and workers will start
when invoked.

When ran in development mode (LEMUR_CONFIG=<location of development configuration file. To run both the celery
beat scheduler and a worker simultaneously, and to have jobs kick off starting at the next minute, run the following
command: celery -A lemur.common.celery worker --loglevel=info -l DEBUG -B

"""
import copy
import sys
from datetime import datetime, timezone, timedelta

from celery import Celery
from flask import current_app

from lemur.authorities.service import get as get_authority
from lemur.factory import create_app
from lemur.notifications.messaging import send_pending_failure_notification
from lemur.pending_certificates import service as pending_certificate_service
from lemur.plugins.base import plugins
from lemur.sources.cli import clean, sync, validate_sources

flask_app = create_app()


def make_celery(app):
    celery = Celery(app.import_name, backend=app.config['CELERY_RESULT_BACKEND'],
                    broker=app.config['CELERY_BROKER_URL'])
    celery.conf.update(app.config)
    TaskBase = celery.Task

    class ContextTask(TaskBase):
        abstract = True

        def __call__(self, *args, **kwargs):
            with app.app_context():
                return TaskBase.__call__(self, *args, **kwargs)

    celery.Task = ContextTask
    return celery


celery = make_celery(flask_app)


@celery.task()
def fetch_acme_cert(id):
    """
    Attempt to get the full certificate for the pending certificate listed.

    Args:
        id: an id of a PendingCertificate
    """
    log_data = {
        "function": "{}.{}".format(__name__, sys._getframe().f_code.co_name)
    }
    pending_certs = pending_certificate_service.get_pending_certs([id])
    new = 0
    failed = 0
    wrong_issuer = 0
    acme_certs = []

    # We only care about certs using the acme-issuer plugin
    for cert in pending_certs:
        cert_authority = get_authority(cert.authority_id)
        if cert_authority.plugin_name == 'acme-issuer':
            acme_certs.append(cert)
        else:
            wrong_issuer += 1

    authority = plugins.get("acme-issuer")
    resolved_certs = authority.get_ordered_certificates(acme_certs)

    for cert in resolved_certs:
        real_cert = cert.get("cert")
        # It's necessary to reload the pending cert due to detached instance: http://sqlalche.me/e/bhk3
        pending_cert = pending_certificate_service.get(cert.get("pending_cert").id)
        if not pending_cert:
            log_data["message"] = "Pending certificate doesn't exist anymore. Was it resolved by another process?"
            current_app.logger.error(log_data)
            continue
        if real_cert:
            # If a real certificate was returned from issuer, then create it in Lemur and mark
            # the pending certificate as resolved
            final_cert = pending_certificate_service.create_certificate(pending_cert, real_cert, pending_cert.user)
            pending_certificate_service.update(
                cert.get("pending_cert").id,
                resolved=True
            )
            pending_certificate_service.update(
                cert.get("pending_cert").id,
                resolved_cert_id=final_cert.id
            )
            # add metrics to metrics extension
            new += 1
        else:
            failed += 1
            error_log = copy.deepcopy(log_data)
            error_log["message"] = "Pending certificate creation failure"
            error_log["pending_cert_id"] = pending_cert.id
            error_log["last_error"] = cert.get("last_error")
            error_log["cn"] = pending_cert.cn

            if pending_cert.number_attempts > 4:
                error_log["message"] = "Deleting pending certificate"
                send_pending_failure_notification(pending_cert, notify_owner=pending_cert.notify)
                # Mark the pending cert as resolved
                pending_certificate_service.update(
                    cert.get("pending_cert").id,
                    resolved=True
                )
            else:
                pending_certificate_service.increment_attempt(pending_cert)
                pending_certificate_service.update(
                    cert.get("pending_cert").id,
                    status=str(cert.get("last_error"))
                )
                # Add failed pending cert task back to queue
                fetch_acme_cert.delay(id)
            current_app.logger.error(error_log)
    log_data["message"] = "Complete"
    log_data["new"] = new
    log_data["failed"] = failed
    log_data["wrong_issuer"] = wrong_issuer
    current_app.logger.debug(log_data)
    print(
        "[+] Certificates: New: {new} Failed: {failed} Not using ACME: {wrong_issuer}".format(
            new=new,
            failed=failed,
            wrong_issuer=wrong_issuer
        )
    )


@celery.task()
def fetch_all_pending_acme_certs():
    """Instantiate celery workers to resolve all pending Acme certificates"""
    pending_certs = pending_certificate_service.get_unresolved_pending_certs()

    # We only care about certs using the acme-issuer plugin
    for cert in pending_certs:
        cert_authority = get_authority(cert.authority_id)
        if cert_authority.plugin_name == 'acme-issuer':
            if cert.last_updated == cert.date_created or datetime.now(
                    timezone.utc) - cert.last_updated > timedelta(minutes=5):
                fetch_acme_cert.delay(cert.id)


@celery.task()
def remove_old_acme_certs():
    """Prune old pending acme certificates from the database"""
    log_data = {
        "function": "{}.{}".format(__name__, sys._getframe().f_code.co_name)
    }
    pending_certs = pending_certificate_service.get_pending_certs('all')

    # Delete pending certs more than a week old
    for cert in pending_certs:
        if datetime.now(timezone.utc) - cert.last_updated > timedelta(days=7):
            log_data['pending_cert_id'] = cert.id
            log_data['pending_cert_name'] = cert.name
            log_data['message'] = "Deleting pending certificate"
            current_app.logger.debug(log_data)
            pending_certificate_service.delete(cert.id)


@celery.task()
def clean_all_sources():
    """
    This function will clean unused certificates from sources. This is a destructive operation and should only
    be ran periodically. This function triggers one celery task per source.
    """
    sources = validate_sources("all")
    for source in sources:
        current_app.logger.debug("Creating celery task to clean source {}".format(source.label))
        clean_source.delay(source.label)


@celery.task()
def clean_source(source):
    """
    This celery task will clean the specified source. This is a destructive operation that will delete unused
    certificates from each source.

    :param source:
    :return:
    """
    current_app.logger.debug("Cleaning source {}".format(source))
    clean([source], True)


@celery.task()
def sync_all_sources():
    """
        This function will sync certificates from all sources. This function triggers one celery task per source.
        """
    sources = validate_sources("all")
    for source in sources:
        current_app.logger.debug("Creating celery task to sync source {}".format(source.label))
        sync_source.delay(source.label)


@celery.task()
def sync_source(source):
    """
    This celery task will sync the specified source.

    :param source:
    :return:
    """
    current_app.logger.debug("Syncing source {}".format(source))
    sync([source], True)