Add form validation to eliminate duplicate partnerships of same type

Extend RSR_PartnershipInlineFormFormSet.clean() to include checking if an
organisation is has duplicate partnerships of the same partner_type and
complain if that is the case

[Fix #35]

akvo/rsr/admin.py

@@ -376,36 +376,61 @@ class GoalInline(admin.TabularInline):
 
 class RSR_PartnershipInlineFormFormSet(forms.models.BaseInlineFormSet):
     def clean(self):
+        def duplicates_in_list(seq):
+            "return True if the list contains duplicate items"
+            seq_set = list(set(seq))
+            # need to sort since set() doesn't preserver order
+            seq.sort()
+            seq_set.sort()
+            return seq != seq_set
+
         user = self.request.user
         user_profile = user.get_profile()
+        errors = []
         # superusers can do whatever they like!
         if user.is_superuser:
-            found = True
+            my_org_found = True
         # if the user is a partner org we try to avoid foot shooting
         elif user_profile.get_is_org_admin() or user_profile.get_is_org_editor():
             my_org = user_profile.organisation
-            found = False
-            for i in range(0, self.total_form_count()):
-                form = self.forms[i]
+            my_org_found = False
+            for form in self.forms:
                 try:
                     form_org = form.cleaned_data['organisation']
                     if not form.cleaned_data.get('DELETE', False) and my_org == form_org:
                         # found our own org, all is well move on!
-                        found = True
+                        my_org_found = True
                         break
                 except:
                     pass
         else:
-            found = True
-        if not found:
-            self._non_form_errors = ErrorList([_(u'Your organisation should be somewhere here.')])
+            my_org_found = True
+        if not my_org_found:
+            errors += [_(u'Your organisation should be somewhere here.')]
+
+        # now check that the same org isn't assigned the same partner_type more than once
+        partner_types = {}
+        for form in self.forms:
+            # populate a dict with org names as keys and a list of partner_types as values
+            try:
+                if not form.cleaned_data.get('DELETE', False):
+                    partner_types.setdefault(form.cleaned_data['organisation'], []).append(form.cleaned_data['partner_type'])
+            except:
+                pass
+        for org, types in partner_types.items():
+            # are there duplicates in the list of partner_types?
+            if duplicates_in_list(types):
+                errors += [_(u'%s has duplicate partner types of the same kind.' % org)]
+        self._non_form_errors = ErrorList(errors)
+
 
 class PartnershipInline(admin.TabularInline):
     model = get_model('rsr', 'Partnership')
     extra = 1
     formset = RSR_PartnershipInlineFormFormSet
 
     def get_formset(self, request, *args, **kwargs):
+        "Add the request to the formset for use in RSR_PartnershipInlineFormFormSet.clean()"
         formset = super(PartnershipInline, self).get_formset(request, *args, **kwargs)
         formset.request = request
         return formset