from datetime import datetime
from flask import current_app
from werkzeug.utils import secure_filename
from .. import db
from ..models import Job, JobResult
import docker
import json
import os
import shutil


class CheckJobsMixin:
    def check_jobs(self):
        jobs = Job.query.all()
        for job in (x for x in jobs if x.status == 'submitted'):
            self.create_job_service(job)
        for job in (x for x in jobs if x.status in ['queued', 'running']):
            self.checkout_job_service(job)
        for job in (x for x in jobs if x.status == 'canceling'):
            self.remove_job_service(job)

    def create_job_service(self, job):
        ''' # Docker service settings # '''
        ''' ## Service specific settings ## '''
        if job.service == 'file-setup':
            mem_mb = 2048
            n_cores = 2
            executable = 'file-setup'
            image = f'{current_app.config["NOPAQUE_DOCKER_IMAGE_PREFIX"]}file-setup:{job.service_version}'  # noqa
        elif job.service == 'ocr':
            mem_mb = 4096
            n_cores = 4
            executable = 'ocr'
            image = f'{current_app.config["NOPAQUE_DOCKER_IMAGE_PREFIX"]}ocr:{job.service_version}'  # noqa
        elif job.service == 'nlp':
            mem_mb = 2048
            n_cores = 2
            executable = 'nlp'
            image = f'{current_app.config["NOPAQUE_DOCKER_IMAGE_PREFIX"]}nlp:{job.service_version}'  # noqa
        ''' ## Command ## '''
        command = f'{executable} -i /input -o /output'
        command += ' --log-dir /input'
        command += f' --mem-mb {mem_mb}'
        command += f' --n-cores {n_cores}'
        command += f' --zip [{job.service}]_{secure_filename(job.title)}'
        command += ' ' + ' '.join(json.loads(job.service_args))
        ''' ## Constraints ## '''
        constraints = ['node.role==worker']
        ''' ## Labels ## '''
        labels = {
            'origin': current_app.config['SERVER_NAME'],
            'type': 'job',
            'job_id': str(job.id)
        }
        ''' ## Mounts ## '''
        ''' ### Input mount ### '''
        input_mount_source = job.path
        input_mount_target = '/input'
        if job.service == 'file-setup':
            input_mount_target += f'/{secure_filename(job.title)}'
        input_mount = f'{input_mount_source}:{input_mount_target}:rw'
        ''' ### Output mount ### '''
        output_mount_source = os.path.join(job.path, 'output')
        output_mount_target = '/output'
        output_mount = f'{output_mount_source}:{output_mount_target}:rw'
        # Make sure that their is no data in the output directory
        shutil.rmtree(output_mount_source, ignore_errors=True)
        os.makedirs(output_mount_source)
        mounts = [input_mount, output_mount]
        ''' ## Name ## '''
        name = f'job_{job.id}'
        ''' ## Resources ## '''
        resources = docker.types.Resources(
            cpu_reservation=n_cores * (10 ** 9),
            mem_reservation=mem_mb * (10 ** 6)
        )
        ''' ## Restart policy ## '''
        restart_policy = docker.types.RestartPolicy()
        try:
            self.docker.services.create(
                image,
                command=command,
                constraints=constraints,
                labels=labels,
                mounts=mounts,
                name=name,
                resources=resources,
                restart_policy=restart_policy
            )
        except docker.errors.APIError as e:
            current_app.logger.error(
                f'Create service "{name}" failed '
                + f'due to "docker.errors.APIError": {e}'
            )
            return
        job.status = 'queued'

    def checkout_job_service(self, job):
        service_name = f'job_{job.id}'
        try:
            service = self.docker.services.get(service_name)
        except docker.errors.NotFound as e:
            current_app.logger.error(
                f'Get service "{service_name}" failed '
                + f'due to "docker.errors.NotFound": {e}'
            )
            job.status = 'failed'
            return
        except docker.errors.APIError as e:
            current_app.logger.error(
                f'Get service "{service_name}" failed '
                + f'due to "docker.errors.APIError": {e}'
            )
            return
        service_tasks = service.tasks()
        if not service_tasks:
            return
        task_state = service_tasks[0].get('Status').get('State')
        if job.status == 'queued' and task_state != 'pending':
            job.status = 'running'
            return
        elif job.status == 'running' and task_state == 'complete':
            job.status = 'complete'
            results_dir = os.path.join(job.path, 'output')
            result_files = [x for x in os.listdir(results_dir) if x.endswith('.zip')]  # noqa
            for result_file in result_files:
                job_result = JobResult(filename=result_file, job=job)
                db.session.add(job_result)
                db.session.flush()
                db.session.refresh(job_result)
        elif job.status == 'running' and task_state == 'failed':
            job.status = 'failed'
        else:
            return
        job.end_date = datetime.utcnow()
        try:
            service.remove()
        except docker.errors.APIError as e:
            current_app.logger.error(
                f'Remove service "{service_name}" failed '
                + f'due to "docker.errors.APIError": {e}'
            )

    def remove_job_service(self, job):
        service_name = f'job_{job.id}'
        try:
            service = self.docker.services.get(service_name)
        except docker.errors.NotFound:
            job.status = 'canceled'
            return
        except docker.errors.APIError as e:
            current_app.logger.error(
                f'Get service "{service_name}" failed '
                + f'due to "docker.errors.APIError": {e}'
            )
            return
        try:
            service.update(mounts=None)
        except docker.errors.APIError as e:
            current_app.logger.error(
                f'Update service "{service_name}" failed '
                + f'due to "docker.errors.APIError": {e}'
            )
            return
        try:
            service.remove()
        except docker.errors.APIError as e:
            current_app.logger.error(
                f'Remove "{service_name}" service failed '
                + f'due to "docker.errors.APIError": {e}'
            )