Initial import of the document states app

mayan/apps/document_states/models.py

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+from __future__ import unicode_literals
+
+from django.db import models
+from django.utils.encoding import python_2_unicode_compatible
+from django.utils.translation import ugettext as _
+
+from documents.models import Document, DocumentType
+
+
+@python_2_unicode_compatible
+class Workflow(models.Model):
+    label = models.CharField(max_length=255, unique=True, verbose_name=_('Label'))
+
+    def __str__(self):
+        return self.label
+
+    def get_initial_state(self):
+        try:
+            return self.states.get(initial=True)
+        except self.states.model.DoesNotExist:
+            return None
+
+    class Meta:
+        verbose_name = _('Workflow')
+        verbose_name_plural = _('Workflows')
+
+
+@python_2_unicode_compatible
+class WorkflowState(models.Model):
+    workflow = models.ForeignKey(Workflow, related_name='states', verbose_name=_('Workflow'))
+    label = models.CharField(max_length=255, verbose_name=_('Label'))
+    initial = models.BooleanField(default=False, verbose_name=_('Initial'))
+
+    def __str__(self):
+        return self.label
+
+    def save(self, *args, **kwargs):
+        if self.initial:
+            self.workflow.states.all().update(initial=False)
+        return super(WorkflowState, self).save(*args, **kwargs)
+
+    class Meta:
+        unique_together = ('workflow', 'label')
+        verbose_name = _('Workflow state')
+        verbose_name_plural = _('Workflow states')
+
+
+@python_2_unicode_compatible
+class WorkflowTransition(models.Model):
+    workflow = models.ForeignKey(Workflow, related_name='transitions', verbose_name=_('Workflow'))
+    label = models.CharField(max_length=255, verbose_name=_('Label'))
+
+    origin_state = models.ForeignKey(WorkflowState, related_name='origins', verbose_name=_('Origin state'))
+    destination_state = models.ForeignKey(WorkflowState, related_name='destinations', verbose_name=_('Destination state'))
+
+    def __str__(self):
+        return self.label
+
+    class Meta:
+        unique_together = ('workflow', 'label', 'origin_state', 'destination_state')
+        verbose_name = _('Workflow transition')
+        verbose_name_plural = _('Workflow transitions')
+
+
+@python_2_unicode_compatible
+class DocumentTypeWorkflow(models.Model):
+    document_type = models.ForeignKey(DocumentType, verbose_name=_('Document type'))
+    workflow = models.ForeignKey(Workflow, verbose_name=_('Workflow'))
+
+    def __str__(self):
+        return self.label
+
+    class Meta:
+        unique_together = ('document_type', 'workflow')
+        verbose_name = _('Document type workflow')
+        verbose_name_plural = _('Document type workflow')
+
+
+@python_2_unicode_compatible
+class WorkflowInstance(models.Model):
+    workflow = models.ForeignKey(Workflow, verbose_name=_('Workflow'))
+    document = models.ForeignKey(Document, verbose_name=_('Document'))
+
+    def do_transition(self, transition):
+        try:
+            if transition in self.get_current_state().origins:
+                self.log_entries.create(transition=transition)
+        except AttributeError:
+            # No initial state has been set for this workflow
+            pass
+
+    def get_current_state(self):
+        try:
+            return self.log_entries.order_by('datetime').last().transition.destination_state
+        except AttributeError:
+            return self.workflow.get_initial_state()
+
+    def __str__(self):
+        return self.label
+
+    class Meta:
+        unique_together = ('document', 'workflow')
+        verbose_name = _('Workflow instance')
+        verbose_name_plural = _('Workflow instances')
+
+
+@python_2_unicode_compatible
+class WorkflowInstanceLogEntry(models.Model):
+    workflow_instance = models.ForeignKey(WorkflowInstance, related_name='log_entries', verbose_name=_('Workflow instance'))
+    datetime = models.DateTimeField(auto_now_add=True, verbose_name=_('Datetime'))
+    transition = models.ForeignKey(WorkflowTransition, verbose_name=_('Transition'))
+
+    def __str__(self):
+        return self.label
+
+    class Meta:
+        verbose_name = _('Workflow instance log entry')
+        verbose_name_plural = _('Workflow instance log entries')