from datetime import datetime
from flask import current_app, flash, redirect, render_template, url_for
from . import services
from flask_login import current_user, login_required
from .forms import OCRJobForm
from ..import swarm
from threading import Thread
import hashlib
import os


@services.route('/ocr', methods=['GET', 'POST'])
@login_required
def ocr():
    ocr_job_form = OCRJobForm()
    if ocr_job_form.validate_on_submit():
        app = current_app._get_current_object()
        id = hashlib.md5(
            (current_user.username + '_' + datetime.now().isoformat()).encode()
        ).hexdigest()
        dir = os.path.join(app.config['OPAQUE_FILES'], 'jobs', id)

        try:
            os.mkdir(dir)
        except FileExistsError:
            # Possible MD5 hash collision occurred.
            flash('Internal error occurred, please try again!')
        else:
            file = ocr_job_form.file.data
            file.save(os.path.join(dir, file.filename))

            '''
            ' TODO: Implement a Job class. For now a dictionary representation
            '       is enough.
            '''
            job = {'worker': None,
                   'creator': current_user.id,
                   'id': id,
                   'requested_cpus': 2,
                   'requested_memory': 2048,
                   'service': 'ocr',
                   'service_args': {'lang': ocr_job_form.language.data,
                                    'version': 'latest'
                                    },
                   'status': 'queued'
                   }
            '''
            ' TODO: Let the scheduler run this job in the background.
            '
            ' NOTE: Using self created threads is just for testing purpose as
            '       there is no scheduler available.
            '''
            thread = Thread(target=swarm.run, args=(job,))
            thread.start()
        return redirect(url_for('services.ocr'))

    return render_template(
        'services/ocr.html.j2',
        title='Optical Character Recognition',
        ocr_job_form=ocr_job_form
    )