project_services.py

from django.db import transaction
from .models import Project as ProjectModel
from .errors import RevisionError, check_user_organisation
from . import project_file_services


def to_model(project):
    return ProjectModel(
        id=project.id,
        revision=project.revision,
        data=project.data,
        organisation_id=project.organisation_id,
    )


def from_model(model, files=None):
    return Project(
        id=model.id,
        revision=model.revision,
        data=model.data,
        organisation_id=model.organisation_id,
        files=files,
    )


def queryset_for_user(user):
    return ProjectModel.objects.filter(organisation_id=user.organisation_id)


def load_project_as_user(user, id):
    check_user_organisation(user)
    model = queryset_for_user(user).get(id=id)
    files = project_file_services.load_files_for_project_as_user(
        user=user, project_id=id
    )
    return from_model(model, files=files)


def load_projects_as_user(user):
    check_user_organisation(user)
    models = queryset_for_user(user).all()
    return map(from_model, models)


def create_project_as_user(project, user):
    check_user_organisation(user)
    if project.id is not None:
        raise ValueError("Cannot create project with id")
    if project.revision != 0:
        raise ValueError("Cannot create project with non-zero revision")

    model = to_model(project)
    model.organisation_id = user.organisation_id
    model.revision += 1
    model.save()

    # There are no files because we just created it
    return from_model(model, files=[])


def update_project_as_user(project, user):
    check_user_organisation(user)
    if project.id is None:
        raise ValueError("Cannot update project without id")
    if project.revision is None or project.revision < 1:
        raise ValueError(
            "Project revision must be greater than or equal to 1 to update"
        )

    with transaction.atomic():
        model = queryset_for_user(user).select_for_update().get(id=project.id)
        if model.revision != project.revision:
            raise RevisionError("Revision is incorrect. Update blocked.")

        # Only the data field can be updated
        model.data = project.data
        model.revision += 1
        model.save()

    files = project_file_services.load_files_for_project_as_user(
        user=user, project_id=project.id
    )
    return from_model(model, files=files)


class Project:
    def __init__(self, data, id=None, organisation_id=None, files=None, revision=0):
        self.id = id
        self.revision = revision
        self.data = data
        self.organisation_id = organisation_id
        self.files = files