Fix remove integration with multiple consumers

Currently removing an integration with an offer removes
the remote offer. This does not take into consideration
of any other consumers integrated with the offer.
This leads to other consumers getting relation-broken
which is not expected.

Remove the integration using DestroyIntegration irrespective
of whether the endpoint is an offer or not.

Fixes: #308

internal/juju/offers.go

@@ -50,11 +50,12 @@ type ReadOfferInput struct {
 }
 
 type ReadOfferResponse struct {
-	ApplicationName string
-	Endpoint        string
-	ModelName       string
-	Name            string
-	OfferURL        string
+	ApplicationName  string
+	Endpoint         string
+	ModelName        string
+	Name             string
+	OfferURL         string
+	ConnectionsCount int
 }
 
 type DestroyOfferInput struct {
@@ -173,6 +174,7 @@ func (c offersClient) ReadOffer(input *ReadOfferInput) (*ReadOfferResponse, erro
 	response.ApplicationName = result.ApplicationName
 	response.OfferURL = result.OfferURL
 	response.Endpoint = result.Endpoints[0].Name
+	response.ConnectionsCount = len(result.Connections)
 
 	//no model name is returned but it can be parsed from the resulting offer URL to ensure parity
 	//TODO: verify if we can fetch information another way

internal/provider/resource_integration.go

@@ -405,33 +405,20 @@ func (r *integrationResource) Delete(ctx context.Context, req resource.DeleteReq
 
 	var apps []nestedApplication
 	state.Application.ElementsAs(ctx, &apps, false)
-	endpoints, offer, _, err := parseEndpoints(apps)
+	endpoints, _, _, err := parseEndpoints(apps)
 	if err != nil {
 		resp.Diagnostics.AddError("Provider Error", err.Error())
 		return
 	}
 
-	//If one of the endpoints is an offer then we need to remove the remote offer rather than destroying the integration
-	if offer != nil {
-		errs := r.client.Offers.RemoveRemoteOffer(&juju.RemoveRemoteOfferInput{
-			ModelName: modelName,
-			OfferURL:  *offer,
-		})
-		if len(errs) > 0 {
-			for _, v := range errs {
-				resp.Diagnostics.AddError("Client Error", v.Error())
-			}
-			return
-		}
-	} else {
-		err = r.client.Integrations.DestroyIntegration(&juju.IntegrationInput{
-			ModelName: modelName,
-			Endpoints: endpoints,
-		})
-		if err != nil {
-			resp.Diagnostics.AddError("Client Error", err.Error())
-			return
-		}
+	// Remove the integration
+	err = r.client.Integrations.DestroyIntegration(&juju.IntegrationInput{
+		ModelName: modelName,
+		Endpoints: endpoints,
+	})
+	if err != nil {
+		resp.Diagnostics.AddError("Client Error", err.Error())
+		return
 	}
 	r.trace(fmt.Sprintf("Deleted integration resource: %q", state.ID.ValueString()))
 }

internal/provider/resource_integration_test.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"testing"
 
+	"github.com/hashicorp/terraform-plugin-testing/config"
 	"github.com/hashicorp/terraform-plugin-testing/helper/acctest"
 	"github.com/hashicorp/terraform-plugin-testing/helper/resource"
 	"github.com/hashicorp/terraform-plugin-testing/terraform"
@@ -250,3 +251,144 @@ resource "juju_integration" "a" {
 }
 `, srcModelName, dstModelName, viaCIDRs)
 }
+
+func TestAcc_ResourceIntegrationWithMultipleConsumers_Edge(t *testing.T) {
+	if testingCloud != LXDCloudTesting {
+		t.Skip(t.Name() + " only runs with LXD")
+	}
+	srcModelName := acctest.RandomWithPrefix("tf-test-integration")
+	dstModelName := acctest.RandomWithPrefix("tf-test-integration-dst")
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:                 func() { testAccPreCheck(t) },
+		ProtoV6ProviderFactories: frameworkProviderFactories,
+		CheckDestroy:             testAccCheckIntegrationDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccResourceIntegrationMultipleConsumers(srcModelName, dstModelName),
+				ConfigVariables: config.Variables{
+					"enable-b1-consumer": config.BoolVariable(true),
+					"enable-b2-consumer": config.BoolVariable(true),
+				},
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr("juju_integration.b1.0", "model", dstModelName),
+					resource.TestCheckResourceAttr("juju_integration.b1.0", "id", fmt.Sprintf("%v:%v:%v", dstModelName, "a:db-admin", "b1:backend-db-admin")),
+					resource.TestCheckResourceAttr("juju_integration.b1.0", "application.#", "2"),
+					resource.TestCheckTypeSetElemNestedAttrs("juju_integration.b1.0", "application.*", map[string]string{"name": "b1", "endpoint": "backend-db-admin"}),
+					resource.TestCheckResourceAttr("juju_integration.b2.0", "model", dstModelName),
+					resource.TestCheckResourceAttr("juju_integration.b2.0", "id", fmt.Sprintf("%v:%v:%v", dstModelName, "a:db-admin", "b2:backend-db-admin")),
+					resource.TestCheckResourceAttr("juju_integration.b2.0", "application.#", "2"),
+					resource.TestCheckTypeSetElemNestedAttrs("juju_integration.b2.0", "application.*", map[string]string{"name": "b2", "endpoint": "backend-db-admin"}),
+				),
+			},
+			{
+				Config: testAccResourceIntegrationMultipleConsumers(srcModelName, dstModelName),
+				ConfigVariables: config.Variables{
+					"enable-b1-consumer": config.BoolVariable(true),
+					"enable-b2-consumer": config.BoolVariable(false),
+				},
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr("juju_integration.b1.0", "model", dstModelName),
+					resource.TestCheckResourceAttr("juju_integration.b1.0", "id", fmt.Sprintf("%v:%v:%v", dstModelName, "a:db-admin", "b1:backend-db-admin")),
+					resource.TestCheckResourceAttr("juju_integration.b1.0", "application.#", "2"),
+					resource.TestCheckTypeSetElemNestedAttrs("juju_integration.b1.0", "application.*", map[string]string{"name": "b1", "endpoint": "backend-db-admin"}),
+				),
+			},
+			{
+				Config: testAccResourceIntegrationMultipleConsumers(srcModelName, dstModelName),
+				ConfigVariables: config.Variables{
+					"enable-b1-consumer": config.BoolVariable(false),
+					"enable-b2-consumer": config.BoolVariable(false),
+				},
+			},
+		},
+	})
+}
+
+// testAccResourceIntegrationWithMultipleConusmers generates a plan where a
+// two pgbouncer applications relates to postgresql:db-admin offer.
+func testAccResourceIntegrationMultipleConsumers(srcModelName string, dstModelName string) string {
+	return fmt.Sprintf(`
+resource "juju_model" "a" {
+        name = %q
+}
+
+resource "juju_application" "a" {
+        model = juju_model.a.name
+        name  = "a"
+
+        charm {
+                name    = "postgresql"
+                series  = "jammy"
+        }
+}
+
+resource "juju_offer" "a" {
+        model            = juju_model.a.name
+        application_name = juju_application.a.name
+        endpoint         = "db-admin"
+}
+
+resource "juju_model" "b" {
+        name = %q
+}
+
+resource "juju_application" "b1" {
+        model = juju_model.b.name
+        name  = "b1"
+
+        charm {
+                name   = "pgbouncer"
+                series = "focal"
+        }
+}
+
+resource "juju_integration" "b1" {
+	count = var.enable-b1-consumer ? 1 : 0
+        model = juju_model.b.name
+
+        application {
+                name     = juju_application.b1.name
+                endpoint = "backend-db-admin"
+        }
+
+        application {
+                offer_url = juju_offer.a.url
+        }
+}
+
+resource "juju_application" "b2" {
+        model = juju_model.b.name
+        name  = "b2"
+
+        charm {
+                name   = "pgbouncer"
+                series = "focal"
+        }
+}
+
+resource "juju_integration" "b2" {
+	count = var.enable-b2-consumer ? 1 : 0
+        model = juju_model.b.name
+
+        application {
+                name     = juju_application.b2.name
+                endpoint = "backend-db-admin"
+        }
+
+        application {
+                offer_url = juju_offer.a.url
+        }
+}
+
+variable "enable-b1-consumer" {
+	description = "Enable integration for b1 with offer"
+	default     = false
+}
+
+variable "enable-b2-consumer" {
+        description = "Enable integration for b2 with offer"
+        default     = false
+}
+`, srcModelName, dstModelName)
+}