flows.py

from django.core.exceptions import ValidationError, PermissionDenied

from .models import QualityProcess
from .utils.flow import task_loader
from viewflow import flow, lock
from viewflow.base import Flow, this


class QualityFlow(Flow):

    """ Implement a qualification process. """

    process_cls = QualityProcess
    lock_impl = lock.select_for_update_lock

    # Start a quality process
    @flow.StartFunction
    def start(activation, organization):
        """ Start the qualification process. """

        if organization.role != 'supplier':
            raise ValidationError('Invalid organization')

        activation.prepare()
        activation.process.organization = organization
        activation.done()

    start.Next(this.approve)

    # Approve a quality process
    @flow.Function
    @flow.flow_func(task_loader=task_loader)
    def approve(activation, process, reviewer=None, level=0, approve=True):
        activation.prepare()

        if not (reviewer and reviewer.is_personal):
            raise PermissionDenied

        activation.process.approved = approve
        activation.process.reviewed_by = reviewer
        activation.process.level = level
        activation.process.save()

        activation.done()

    approve.Next(this.check_approve)

    check_approve = flow.If(cond=lambda p: p.approved)\
        .OnTrue(this.send_approved)\
        .OnFalse(this.send_rejected)

    @flow.Function
    @flow.flow_func(task_loader=task_loader)
    def send_approved(activation, process, *args, **kwargs):
        activation.prepare()
        activation.done()

    send_approved.Next(this.end)

    @flow.Function
    @flow.flow_func(task_loader=task_loader)
    def send_rejected(activation, process, *args, **kwargs):
        activation.prepare()
        activation.done()

    send_rejected.Next(this.end)

    end = flow.End()