From eb98ba0f6ef12caf06b6e47cb8b75d33fdec8381 Mon Sep 17 00:00:00 2001
From: Rithvik Nishad <rithvik.nishad@egovernments.org>
Date: Tue, 11 Jul 2023 08:58:07 +0000
Subject: [PATCH] Medibase: Drop littletable; instead store as list from ORM's
 `values_list` (#1443)

* custom in memory search

* as tuple

* fix tests

* remove db queryset reference after loading to in-memory

* minor optimization

* remove commented code

* load to in-mem using ORM's `values_list`

* Update care/facility/api/viewsets/prescription.py

Co-authored-by: Aakash Singh <mail@singhaakash.dev>

---------

Co-authored-by: Aakash Singh <mail@singhaakash.dev>
---
 care/facility/api/viewsets/prescription.py | 50 +++++++++-------------
 care/facility/static_data/medibase.py      | 48 ++++++++++++---------
 config/wsgi.py                             |  2 +
 3 files changed, 50 insertions(+), 50 deletions(-)

diff --git a/care/facility/api/viewsets/prescription.py b/care/facility/api/viewsets/prescription.py
index ff1dfaa3a1..e6007e72c3 100644
--- a/care/facility/api/viewsets/prescription.py
+++ b/care/facility/api/viewsets/prescription.py
@@ -1,5 +1,3 @@
-from re import IGNORECASE
-
 from django.shortcuts import get_object_or_404
 from django_filters import rest_framework as filters
 from drf_spectacular.utils import extend_schema
@@ -140,36 +138,30 @@ class MedibaseViewSet(ViewSet):
     permission_classes = (IsAuthenticated,)
 
     def serailize_data(self, objects):
-        result = []
-        for object in objects:
-            if type(object) == tuple:
-                object = object[0]
-            result.append(
-                {
-                    "id": object.external_id,
-                    "name": object.name,
-                    "type": object.type,
-                    "generic": object.generic,
-                    "company": object.company,
-                    "contents": object.contents,
-                    "cims_class": object.cims_class,
-                    "atc_classification": object.atc_classification,
-                }
-            )
-        return result
+        return [
+            {
+                "id": x[0],
+                "name": x[1],
+                "type": x[2],
+                "generic": x[3],
+                "company": x[4],
+                "contents": x[5],
+                "cims_class": x[6],
+                "atc_classification": x[7],
+            }
+            for x in objects
+        ]
 
     def sort(self, query, results):
         exact_matches = []
         partial_matches = []
 
-        for result in results:
-            if type(result) == tuple:
-                result = result[0]
-            words = result.searchable.lower().split()
+        for x in results:
+            words = f"{x[1]} {x[3]} {x[4]}".lower().split()
             if query in words:
-                exact_matches.append(result)
+                exact_matches.append(x)
             else:
-                partial_matches.append(result)
+                partial_matches.append(x)
 
         return exact_matches + partial_matches
 
@@ -178,10 +170,8 @@ def list(self, request):
 
         queryset = MedibaseMedicineTable
 
-        if request.GET.get("query", False):
-            query = request.GET.get("query").strip().lower()
-            queryset = queryset.where(
-                searchable=queryset.re_match(r".*" + query + r".*", IGNORECASE)
-            )
+        if query := request.query_params.get("query"):
+            query = query.strip().lower()
+            queryset = [x for x in queryset if query in f"{x[1]} {x[3]} {x[4]}".lower()]
             queryset = self.sort(query, queryset)
         return Response(self.serailize_data(queryset[:15]))
diff --git a/care/facility/static_data/medibase.py b/care/facility/static_data/medibase.py
index 946360635f..fb5718c3df 100644
--- a/care/facility/static_data/medibase.py
+++ b/care/facility/static_data/medibase.py
@@ -1,26 +1,34 @@
-from littletable import Table
+from django.db.models import CharField, TextField, Value
+from django.db.models.functions import Coalesce
 
 from care.facility.models.prescription import MedibaseMedicine
 
-MedibaseMedicineTable = Table("MedibaseMedicine")
 
-medibase_objects = MedibaseMedicine.objects.all()
-
-for obj in medibase_objects:
-    MedibaseMedicineTable.insert(
-        {
-            "id": obj.id,
-            "external_id": obj.external_id,
-            "name": obj.name,
-            "type": obj.type,
-            "generic": obj.generic or "",
-            "company": obj.company or "",
-            "contents": obj.contents or "",
-            "cims_class": obj.cims_class or "",
-            "atc_classification": obj.atc_classification or "",
-            "searchable": f"{obj.name} {obj.generic} {obj.company}",
-        }
+def load_medibase_in_memory():
+    return (
+        MedibaseMedicine.objects.all()
+        .annotate(
+            generic_pretty=Coalesce("generic", Value(""), output_field=CharField()),
+            company_pretty=Coalesce("company", Value(""), output_field=CharField()),
+            contents_pretty=Coalesce("contents", Value(""), output_field=TextField()),
+            cims_class_pretty=Coalesce(
+                "cims_class", Value(""), output_field=CharField()
+            ),
+            atc_classification_pretty=Coalesce(
+                "atc_classification", Value(""), output_field=TextField()
+            ),
+        )
+        .values_list(
+            "external_id",
+            "name",
+            "type",
+            "generic_pretty",
+            "company_pretty",
+            "contents_pretty",
+            "cims_class_pretty",
+            "atc_classification_pretty",
+        )
     )
 
-MedibaseMedicineTable.create_index("id", unique=True)
-MedibaseMedicineTable.create_search_index("searchable")
+
+MedibaseMedicineTable = load_medibase_in_memory()
diff --git a/config/wsgi.py b/config/wsgi.py
index 835d5c2ece..9827d177fd 100644
--- a/config/wsgi.py
+++ b/config/wsgi.py
@@ -36,3 +36,5 @@
 # Apply WSGI middleware here.
 # from helloworld.wsgi import HelloWorldApplication
 # application = HelloWorldApplication(application)
+
+from care.facility.static_data.medibase import MedibaseMedicineTable  # noqa