from app import db, mail, socketio
from app.email import create_message
from app.models import (
    Corpus,
    CorpusFile,
    Job,
    JobInput,
    JobResult,
    JobStatus,
    UserSettingJobStatusMailNotificationLevel
)
from datetime import datetime
from enum import Enum


###############################################################################
# SQLAlchemy event handlers                                                   #
###############################################################################
@db.event.listens_for(Corpus, 'after_delete')
@db.event.listens_for(CorpusFile, 'after_delete')
@db.event.listens_for(Job, 'after_delete')
@db.event.listens_for(JobInput, 'after_delete')
@db.event.listens_for(JobResult, 'after_delete')
def ressource_after_delete(mapper, connection, ressource):
    jsonpatch = [{'op': 'remove', 'path': ressource.jsonpatch_path}]
    room = f'users.{ressource.user_hashid}'
    socketio.emit('users.patch', jsonpatch, room=room)


@db.event.listens_for(Corpus, 'after_insert')
@db.event.listens_for(CorpusFile, 'after_insert')
@db.event.listens_for(Job, 'after_insert')
@db.event.listens_for(JobInput, 'after_insert')
@db.event.listens_for(JobResult, 'after_insert')
def ressource_after_insert_handler(mapper, connection, ressource):
    value = ressource.to_dict(backrefs=False, relationships=False)
    for attr in mapper.relationships:
        value[attr.key] = {}
    jsonpatch = [
        {'op': 'add', 'path': ressource.jsonpatch_path, 'value': value}
    ]
    room = f'users.{ressource.user_hashid}'
    socketio.emit('users.patch', jsonpatch, room=room)


@db.event.listens_for(Corpus, 'after_update')
@db.event.listens_for(CorpusFile, 'after_update')
@db.event.listens_for(Job, 'after_update')
@db.event.listens_for(JobInput, 'after_update')
@db.event.listens_for(JobResult, 'after_update')
def ressource_after_update_handler(mapper, connection, ressource):
    jsonpatch = []
    for attr in db.inspect(ressource).attrs:
        if attr.key in mapper.relationships:
            continue
        if not attr.load_history().has_changes():
            continue
        if isinstance(attr.value, datetime):
            value = attr.value.isoformat() + 'Z'
        elif isinstance(attr.value, Enum):
            value = attr.value.name
        else:
            value = attr.value
        jsonpatch.append(
            {
                'op': 'replace',
                'path': f'{ressource.jsonpatch_path}/{attr.key}',
                'value': value
            }
        )
        if isinstance(ressource, Job) and attr.key == 'status':
            _job_status_email_handler(ressource)
    if jsonpatch:
        room = f'users.{ressource.user_hashid}'
        socketio.emit('users.patch', jsonpatch, room=room)


def _job_status_email_handler(job):
    if job.user.setting_job_status_mail_notification_level == UserSettingJobStatusMailNotificationLevel.NONE:  # noqa
        return
    if job.user.setting_job_status_mail_notification_level == UserSettingJobStatusMailNotificationLevel.END:  # noqa
        if job.status not in [JobStatus.COMPLETED, JobStatus.FAILED]:
            return
    msg = create_message(
        job.user.email,
        f'Status update for your Job "{job.title}"',
        'tasks/email/notification',
        job=job
    )
    mail.send(msg)