From cce335c42ffa5524101fcaa25ecbb112397f43a9 Mon Sep 17 00:00:00 2001
From: SimoneDutto <simone.dutto@canonical.com>
Date: Fri, 6 Sep 2024 15:12:26 +0200
Subject: [PATCH] change from where condition to case

---
 internal/db/resource.go                            | 14 +++++---------
 internal/rebac_admin/resources_integration_test.go | 10 ++++++++++
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/internal/db/resource.go b/internal/db/resource.go
index d8b5500bc..7eaab7749 100644
--- a/internal/db/resource.go
+++ b/internal/db/resource.go
@@ -116,31 +116,27 @@ func (d *Database) ListResources(ctx context.Context, limit, offset int, namePre
 // namePrefixFilter: used to match resources name prefix.
 // typeFilter: used to match resources type. If this is not empty the resources are fetched from a single table.
 func buildQuery(db *gorm.DB, offset, limit int, namePrefixFilter, typeFilter string) (*gorm.DB, error) {
-	// if namePrefixEmpty set to true we have a 'TRUE IS TRUE' in the SQL WHERE statement, which disable the filtering.
-	namePrefixEmpty := namePrefixFilter == ""
-	namePrefixFilter += "%"
-
 	applicationOffersQuery := db.Select(selectApplicationOffers).
 		Model(&dbmodel.ApplicationOffer{}).
-		Where("? IS TRUE OR application_offers.name LIKE ?", namePrefixEmpty, namePrefixFilter).
+		Where("(CASE WHEN ? = '' THEN TRUE ELSE application_offers.name LIKE ? END)", namePrefixFilter, namePrefixFilter+"%").
 		Joins("JOIN models ON application_offers.model_id = models.id")
 
 	cloudsQuery := db.Select(selectClouds).
 		Model(&dbmodel.Cloud{}).
-		Where("? IS TRUE OR clouds.name LIKE ?", namePrefixEmpty, namePrefixFilter)
+		Where("(CASE WHEN ? = '' THEN TRUE ELSE clouds.name LIKE ? END)", namePrefixFilter, namePrefixFilter+"%")
 
 	controllersQuery := db.Select(selectControllers).
 		Model(&dbmodel.Controller{}).
-		Where("? IS TRUE OR controllers.name LIKE ?", namePrefixEmpty, namePrefixFilter)
+		Where("(CASE WHEN ? = '' THEN TRUE ELSE controllers.name LIKE ? END)", namePrefixFilter, namePrefixFilter+"%")
 
 	modelsQuery := db.Select(selectModels).
 		Model(&dbmodel.Model{}).
-		Where("? IS TRUE OR models.name LIKE ?", namePrefixEmpty, namePrefixFilter).
+		Where("(CASE WHEN ? = '' THEN TRUE ELSE models.name LIKE ? END)", namePrefixFilter, namePrefixFilter+"%").
 		Joins("JOIN controllers ON models.controller_id = controllers.id")
 
 	serviceAccountsQuery := db.Select(selectIdentities).
 		Model(&dbmodel.Identity{}).
-		Where("name LIKE '%@serviceaccount' AND (? IS TRUE OR identities.name LIKE ?)", namePrefixEmpty, namePrefixFilter)
+		Where("name LIKE '%@serviceaccount' AND (CASE WHEN ? = '' THEN TRUE ELSE identities.name LIKE ? END)", namePrefixFilter, namePrefixFilter+"%")
 
 	// if the typeFilter is set we only return the query for that specif entityType, otherwise the union.
 	if typeFilter == "" {
diff --git a/internal/rebac_admin/resources_integration_test.go b/internal/rebac_admin/resources_integration_test.go
index a22c9d15f..fc2344110 100644
--- a/internal/rebac_admin/resources_integration_test.go
+++ b/internal/rebac_admin/resources_integration_test.go
@@ -192,6 +192,16 @@ func (s *resourcesSuite) TestListResources(c *gc.C) {
 				return filteredIds
 			}(),
 		},
+		{
+			desc:         "test big page with model entity type",
+			size:         utils.IntToPointer(10),
+			page:         utils.IntToPointer(0),
+			typeFilter:   rebac_admin.Model,
+			wantPage:     0,
+			wantSize:     3,
+			wantNextpage: nil,
+			ids:          []testEntity{},
+		},
 	}
 	for _, t := range testCases {
 		resources, err := resourcesSvc.ListResources(ctx, &resources.GetResourcesParams{