package bootstrap

import (
	"context"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

// aCatalogue is a catalogue checkout holding these modules' manifests.
func aCatalogue(t *testing.T, manifests map[string]string) string {
	t.Helper()
	dir := t.TempDir()
	for module, manifest := range manifests {
		at := filepath.Join(dir, catalogueDir, module)
		if err := os.MkdirAll(at, 0o755); err != nil {
			t.Fatal(err)
		}
		if err := os.WriteFile(filepath.Join(at, "module.json"), []byte(manifest), 0o644); err != nil {
			t.Fatal(err)
		}
	}
	return dir
}

// aBusModule is the nats module's manifest as far as adoption reads it: a server container by name.
func aBusModule(server string) string {
	return `{"module": "nats", "version": "1",
  "claims": [{"name": "mesh-broker", "scope": "mesh"}],
  "bus-users": "/var/lib/nats-module/conf/accounts.conf",
  "resources": [{"id": "server", "type": "container", "name": "` + server + `", "ports": ["4222:4222"], "artifact": "server"}],
  "build": {"artifacts": [{"name": "server", "kind": "image", "from": "Dockerfile"}]}}`
}

func busStep(t *testing.T, catalogue string) (*asked, error) {
	t.Helper()
	rewritten, err := Rewrite(theRealBundle(t), held)
	if err != nil {
		t.Fatal(err)
	}
	runtime := &asked{answer: aMeshThatAgrees(nil)}
	control := controlPlane{container: "mesh-controller", run: runtime.run, timeout: 0}
	err = InstallBroker(context.Background(), installing(t, catalogue), control, rewritten.Declaration, func(string) {})
	return runtime, err
}

// The broker step adopts the foundation's bus as the nats module (novox/hq ADR 0331 §1): the module
// the mesh goes on managing, registered from the catalogue — never lavinmq, which left it.
func TestTheBrokerStepAdoptsTheBusAsTheNatsModule(t *testing.T) {
	catalogue := aCatalogue(t, map[string]string{BusModule: aBusModule("mesh-broker")})
	runtime, _ := busStep(t, catalogue)
	if !runtime.ran("module add /nats-module.json") {
		t.Fatalf("the nats module was not registered: %v", runtime.commands)
	}
	if runtime.ran("lavinmq") {
		t.Errorf("the broker step still speaks of lavinmq: %v", runtime.commands)
	}
}

// A catalogue that holds no nats module fails the step by name, before anything is registered —
// which is what today's step did for lavinmq, silently adopting a module that no longer exists.
func TestTheBrokerStepFailsForAModuleTheCatalogueDoesNotHold(t *testing.T) {
	catalogue := aCatalogue(t, map[string]string{"lavinmq": `{"module": "lavinmq", "version": "1"}`})
	runtime, err := busStep(t, catalogue)
	if err == nil {
		t.Fatal("a catalogue without the nats module was adopted from")
	}
	if !strings.Contains(err.Error(), "nats module") {
		t.Errorf("the refusal does not name the module it looked for: %v", err)
	}
	if runtime.ran("module add") {
		t.Errorf("something was registered: %v", runtime.commands)
	}
}

// A bus module whose server is not the foundation's container by name would raise a second bus
// beside the first; it is refused naming both, before anything is registered.
func TestABusModuleWhoseServerIsNotTheFoundationsIsRefused(t *testing.T) {
	catalogue := aCatalogue(t, map[string]string{BusModule: aBusModule("mesh-broker-nats")})
	runtime, err := busStep(t, catalogue)
	if err == nil {
		t.Fatal("a bus module with another server was adopted")
	}
	for _, named := range []string{"mesh-broker-nats", `"mesh-broker"`} {
		if !strings.Contains(err.Error(), named) {
			t.Errorf("the refusal does not name %s: %v", named, err)
		}
	}
	if runtime.ran("module add") {
		t.Errorf("something was registered: %v", runtime.commands)
	}
}