improve code readability

internal/common/pagination/pagination.go

@@ -44,38 +44,37 @@ func (l LimitOffsetPagination) Offset() int {
 }
 
 // CreatePagination returns the current page, the next page if exists, and the pagination.LimitOffsetPagination.
-func CreatePagination(sizeP, pageP *int, total int) (int, *int, LimitOffsetPagination) {
+func CreatePagination(sizeP, pageP *int, total int) (currentPage int, nextPage *int, _ LimitOffsetPagination) {
 	pageSize := -1
 	offset := 0
-	page := 0
-	var nextPage *int
 
 	if sizeP != nil && pageP != nil {
 		pageSize = *sizeP
-		page = *pageP
-		offset = pageSize * page
+		currentPage = *pageP
+		offset = pageSize * currentPage
 	}
-	if (page+1)*pageSize < total {
-		nPage := page + 1
+	if (currentPage+1)*pageSize < total {
+		nPage := currentPage + 1
 		nextPage = &nPage
 	}
-	return page, nextPage, NewOffsetFilter(pageSize, offset)
+	return currentPage, nextPage, NewOffsetFilter(pageSize, offset)
 }
 
-// CreatePagination returns the current page, the page size, and the pagination.LimitOffsetPagination.
+// CreatePagination returns the current page, the expected page size, and the pagination.LimitOffsetPagination.
 // This method is different approach to the method `CreatePagination` when we don't have the total number of records.
-func CreatePaginationWithoutTotal(sizeP, pageP *int) (int, int, LimitOffsetPagination) {
+// We return the expectedPageSize, which is pageSize +1, so we fetch one record more from the db.
+// We then check the resulting records are enough to advice the consumers to ask for one more page or not.
+func CreatePaginationWithoutTotal(sizeP, pageP *int) (currentPage int, expectedPageSize int, _ LimitOffsetPagination) {
 	pageSize := -1
 	offset := 0
-	page := 0
 
 	if sizeP != nil && pageP != nil {
 		pageSize = *sizeP
-		page = *pageP
-		offset = pageSize * page
+		currentPage = *pageP
+		offset = pageSize * currentPage
 	}
-
-	return page, pageSize + 1, NewOffsetFilter(pageSize+1, offset)
+	expectedPageSize = pageSize + 1
+	return currentPage, expectedPageSize, NewOffsetFilter(pageSize+1, offset)
 }
 
 type OpenFGAPagination struct {

internal/db/resource_test.go

@@ -12,10 +12,10 @@ import (
 	"github.com/canonical/jimm/v3/internal/dbmodel"
 )
 
-func (s *dbSuite) SetupDB(c *qt.C) (dbmodel.Model, dbmodel.Controller, dbmodel.Cloud) {
+func SetupDB(c *qt.C, database *db.Database) (dbmodel.Model, dbmodel.Controller, dbmodel.Cloud) {
 	u, err := dbmodel.NewIdentity("[email protected]")
 	c.Assert(err, qt.IsNil)
-	c.Assert(s.Database.DB.Create(&u).Error, qt.IsNil)
+	c.Assert(database.DB.Create(&u).Error, qt.IsNil)
 
 	cloud := dbmodel.Cloud{
 		Name: "test-cloud",
@@ -24,23 +24,23 @@ func (s *dbSuite) SetupDB(c *qt.C) (dbmodel.Model, dbmodel.Controller, dbmodel.C
 			Name: "test-region",
 		}},
 	}
-	c.Assert(s.Database.DB.Create(&cloud).Error, qt.IsNil)
+	c.Assert(database.DB.Create(&cloud).Error, qt.IsNil)
 
 	cred := dbmodel.CloudCredential{
 		Name:     "test-cred",
 		Cloud:    cloud,
 		Owner:    *u,
 		AuthType: "empty",
 	}
-	c.Assert(s.Database.DB.Create(&cred).Error, qt.IsNil)
+	c.Assert(database.DB.Create(&cred).Error, qt.IsNil)
 
 	controller := dbmodel.Controller{
 		Name:        "test-controller",
 		UUID:        "00000000-0000-0000-0000-0000-0000000000001",
 		CloudName:   "test-cloud",
 		CloudRegion: "test-region",
 	}
-	err = s.Database.AddController(context.Background(), &controller)
+	err = database.AddController(context.Background(), &controller)
 	c.Assert(err, qt.Equals, nil)
 
 	model := dbmodel.Model{
@@ -64,7 +64,7 @@ func (s *dbSuite) SetupDB(c *qt.C) (dbmodel.Model, dbmodel.Controller, dbmodel.C
 			Level: "unsupported",
 		},
 	}
-	err = s.Database.AddModel(context.Background(), &model)
+	err = database.AddModel(context.Background(), &model)
 	c.Assert(err, qt.Equals, nil)
 	return model, controller, cloud
 }
@@ -77,7 +77,7 @@ func (s *dbSuite) TestGetResources(c *qt.C) {
 	c.Assert(err, qt.Equals, nil)
 	c.Assert(res, qt.HasLen, 0)
 	// create one model, one controller, one cloud
-	model, controller, cloud := s.SetupDB(c)
+	model, controller, cloud := SetupDB(c, s.Database)
 	res, err = s.Database.ListResources(ctx, 10, 0)
 	c.Assert(err, qt.Equals, nil)
 	c.Assert(res, qt.HasLen, 3)

internal/rebac_admin/resources.go

@@ -8,6 +8,7 @@ import (
 	"github.com/canonical/rebac-admin-ui-handlers/v1/resources"
 
 	"github.com/canonical/jimm/v3/internal/common/pagination"
+	"github.com/canonical/jimm/v3/internal/db"
 	"github.com/canonical/jimm/v3/internal/jujuapi"
 	"github.com/canonical/jimm/v3/internal/rebac_admin/utils"
 )
@@ -28,28 +29,21 @@ func (s *resourcesService) ListResources(ctx context.Context, params *resources.
 	if err != nil {
 		return nil, err
 	}
-	page, pageSize, pagination := pagination.CreatePaginationWithoutTotal(params.Size, params.Page)
+	currentPage, expectedPageSize, pagination := pagination.CreatePaginationWithoutTotal(params.Size, params.Page)
 	res, err := s.jimm.ListResources(ctx, user, pagination)
 	if err != nil {
 		return nil, err
 	}
-	// We fetch one record more than the page size. Then, we set the next page if we have this many records.
-	// Otherwise next page is empty.
-	var nextPage *int
-	if len(res) == pageSize {
-		nPage := page + 1
-		nextPage = &nPage
-		res = res[:len(res)-1]
-	}
+	nextPage, res := getNextPageAndResources(currentPage, expectedPageSize, res)
 	rRes := make([]resources.Resource, len(res))
 	for i, u := range res {
-		rRes[i] = utils.FromDbResourcesToResources(u)
+		rRes[i] = utils.ToRebacResource(u)
 	}
 
 	return &resources.PaginatedResponse[resources.Resource]{
 		Data: rRes,
 		Meta: resources.ResponseMeta{
-			Page:  &page,
+			Page:  &currentPage,
 			Size:  len(rRes),
 			Total: nil,
 		},
@@ -58,3 +52,17 @@ func (s *resourcesService) ListResources(ctx context.Context, params *resources.
 		},
 	}, nil
 }
+
+// We fetch one record more than the page size.
+// Then, we set the next page if we have this many records.
+// If it does we return the records minus 1 and advide the consumer there is another page.
+// Otherwise we return the records we have and set next page as empty.
+func getNextPageAndResources(currentPage, expectedPageSize int, resources []db.Resource) (*int, []db.Resource) {
+	var nextPage *int
+	if len(resources) == expectedPageSize {
+		nPage := currentPage + 1
+		nextPage = &nPage
+		resources = resources[:len(resources)-1]
+	}
+	return nextPage, resources
+}

internal/rebac_admin/resources_integration_test.go

@@ -19,7 +19,7 @@ type resourcesSuite struct {
 
 var _ = gc.Suite(&resourcesSuite{})
 
-// patchIdentitiesEntitlementTestEnv is used to create entries in JIMM's database.
+// resourcesTestEnv is used to create entries in JIMM's database.
 // The rebacAdminSuite does not spin up a Juju controller so we cannot use
 // regular JIMM methods to create resources. It is also necessary to have resources
 // present in the database in order for ListRelationshipTuples to work correctly.

internal/rebac_admin/utils/utils.go

@@ -29,8 +29,8 @@ func FromUserToIdentity(user openfga.User) resources.Identity {
 	}
 }
 
-// FromUserToIdentity parses openfga.User into resources.Identity .
-func FromDbResourcesToResources(res db.Resource) resources.Resource {
+// ToRebacResource parses db.Resource into resources.Resource.
+func ToRebacResource(res db.Resource) resources.Resource {
 	r := resources.Resource{
 		Entity: resources.Entity{
 			Id:   res.ID.String,