package topaz_test

import (
	"context"
	"errors"
	"os"
	"path/filepath"
	"testing"

	"github.com/netkingdom/flex-auth/internal/adapters/topaz"
	"github.com/netkingdom/flex-auth/internal/policy"
	"github.com/netkingdom/flex-auth/internal/registry"
	"github.com/netkingdom/flex-auth/pkg/api"
)

func TestSnapshotToDirectoryMapsCanonicalRegistry(t *testing.T) {
	store := loadRegistry(t)

	got := topaz.SnapshotToDirectory(store.Snapshot())

	assertObject(t, got, "user", "user:alice")
	assertObject(t, got, "identity", "identity:user:alice")
	assertObject(t, got, "group", "group:platform-architecture")
	assertObject(t, got, "document", "document:internal-note")

	assertRelation(t, got, topaz.DirectoryRelation{
		ObjectType:  "identity",
		ObjectID:    "identity:user:alice",
		Relation:    "identifier",
		SubjectType: "user",
		SubjectID:   "user:alice",
	})
	assertRelation(t, got, topaz.DirectoryRelation{
		ObjectType:  "group",
		ObjectID:    "group:platform-architecture",
		Relation:    "member",
		SubjectType: "user",
		SubjectID:   "user:alice",
	})
	assertRelation(t, got, topaz.DirectoryRelation{
		ObjectType:      "document",
		ObjectID:        "document:internal-note",
		Relation:        "reader",
		SubjectType:     "group",
		SubjectID:       "group:platform-architecture",
		SubjectRelation: "member",
	})
}

func TestAdapterCheckWrapsTopazAllowInFlexAuthEnvelope(t *testing.T) {
	client := &fakeClient{
		checkResult: topaz.CheckResult{
			Allowed:       true,
			DirectoryETag: "etag:rel-42",
			Diagnostics: map[string]any{
				"topaz_trace": "trace-1",
			},
		},
	}
	adapter := newAdapter(t, client)

	got, err := adapter.Check(context.Background(), api.CheckRequest{
		ID:      "check:topaz-allow",
		Subject: api.SubjectRef{ID: "user:alice", Type: api.SubjectTypeHuman},
		Action:  "read",
		Resource: api.ResourceRef{
			ID:     "document:internal-note",
			Type:   "document",
			System: "markitect-tool",
		},
		CaringContext: caringDescriptor(),
	})
	if err != nil {
		t.Fatalf("Check: %v", err)
	}

	if got.Effect != api.DecisionEffectAllow || got.Reason != "topaz_directory_allow" {
		t.Fatalf("decision = %s/%s; want allow/topaz_directory_allow", got.Effect, got.Reason)
	}
	if got.Provenance.Evaluator != topaz.EvaluatorName || got.Provenance.Mode != topaz.DelegatedMode {
		t.Fatalf("provenance = %+v; want delegated Topaz", got.Provenance)
	}
	if got.Provenance.DirectoryETag != "etag:rel-42" {
		t.Fatalf("DirectoryETag = %q", got.Provenance.DirectoryETag)
	}
	if got.Diagnostics["topaz_object_type"] != "document" || got.Diagnostics["topaz_subject_type"] != "user" {
		t.Fatalf("diagnostics = %+v; want Topaz check shape", got.Diagnostics)
	}
	if got.Caring == nil || got.Caring.Descriptor == nil {
		t.Fatal("missing CARING descriptor")
	}
	if len(got.Caring.RestrictionsEvaluated) != 1 || got.Caring.RestrictionsEvaluated[0] != api.RestrictionExportBlocked {
		t.Fatalf("restrictions = %+v; want ExportBlocked", got.Caring.RestrictionsEvaluated)
	}
}

func TestAdapterCheckFailsClosedOnUnavailableTopaz(t *testing.T) {
	client := &fakeClient{
		checkErr: topaz.NewBackendError(topaz.FailureUnavailable, "check", errors.New("connection refused")),
	}
	adapter := newAdapter(t, client)

	got, err := adapter.Check(context.Background(), api.CheckRequest{
		ID:            "check:topaz-down",
		Subject:       api.SubjectRef{ID: "user:alice"},
		Action:        "read",
		Resource:      api.ResourceRef{ID: "document:internal-note", Type: "document", System: "markitect-tool"},
		CaringContext: caringDescriptor(),
	})
	if err != nil {
		t.Fatalf("Check: %v", err)
	}

	if got.Effect != api.DecisionEffectDeny || got.Reason != "topaz_unavailable" {
		t.Fatalf("decision = %s/%s; want deny/topaz_unavailable", got.Effect, got.Reason)
	}
	if got.Diagnostics["topaz_failure"] != "unavailable" {
		t.Fatalf("diagnostics = %+v; want unavailable failure", got.Diagnostics)
	}
	if got.Caring == nil || len(got.Caring.ConformanceFindings) == 0 {
		t.Fatal("fail-closed decision should carry CARING conformance finding")
	}
	if got.Caring.ConformanceFindings[0].Code != "TOPAZ-UNAVAILABLE" {
		t.Fatalf("finding = %+v", got.Caring.ConformanceFindings[0])
	}
}

func TestImportDirectoryWritesObjectsAndRelations(t *testing.T) {
	client := &fakeClient{}
	adapter := newAdapter(t, client)

	report, err := adapter.ImportDirectory(context.Background(), loadRegistry(t).Snapshot())
	if err != nil {
		t.Fatalf("ImportDirectory: %v", err)
	}

	if report.ObjectsWritten != len(client.objects) {
		t.Fatalf("ObjectsWritten = %d; client wrote %d", report.ObjectsWritten, len(client.objects))
	}
	if report.RelationsWritten != len(client.relations) {
		t.Fatalf("RelationsWritten = %d; client wrote %d", report.RelationsWritten, len(client.relations))
	}
	assertWrittenRelation(t, client.relations, topaz.DirectoryRelation{
		ObjectType:      "document",
		ObjectID:        "document:internal-note",
		Relation:        "reader",
		SubjectType:     "group",
		SubjectID:       "group:platform-architecture",
		SubjectRelation: "member",
	})
}

func TestImportPolicyWritesTopazBundle(t *testing.T) {
	pkg, err := policy.LoadAndValidateFile(context.Background(), filepath.Join("..", "..", "..", "examples", "caring", "policy_package.md"))
	if err != nil {
		t.Fatalf("LoadAndValidateFile: %v", err)
	}

	client := &fakeClient{bundleSink: topaz.FileBundleSink{Root: t.TempDir()}}
	adapter := newAdapter(t, client)

	report, err := adapter.ImportPolicy(context.Background(), pkg)
	if err != nil {
		t.Fatalf("ImportPolicy: %v", err)
	}
	if report.BundleID != "markitect.documents.internal-read" || report.Version != "v1" {
		t.Fatalf("report = %+v", report)
	}

	modulePath := filepath.Join(client.bundleSink.Root, "policy", "flexauth", "markitect", "documents.rego")
	data, err := os.ReadFile(modulePath)
	if err != nil {
		t.Fatalf("read module: %v", err)
	}
	if string(data) != pkg.RegoModule {
		t.Fatal("policy module changed during Topaz import")
	}
	manifest, err := os.ReadFile(filepath.Join(client.bundleSink.Root, ".manifest"))
	if err != nil {
		t.Fatalf("read manifest: %v", err)
	}
	if !contains(string(manifest), "flexauth/markitect/documents") {
		t.Fatalf(".manifest = %s", manifest)
	}
}

func loadRegistry(t *testing.T) *registry.Store {
	t.Helper()

	store, err := registry.LoadFile(filepath.Join("..", "..", "..", "examples", "caring", "registry_snapshot.json"))
	if err != nil {
		t.Fatalf("LoadFile: %v", err)
	}
	return store
}

func newAdapter(t *testing.T, client *fakeClient) *topaz.Adapter {
	t.Helper()

	adapter, err := topaz.New(client, topaz.Options{
		PolicyPackage: "markitect.documents.internal-read",
		PolicyVersion: "v1",
	})
	if err != nil {
		t.Fatalf("New: %v", err)
	}
	return adapter
}

func caringDescriptor() *api.CaringAccessDescriptor {
	return &api.CaringAccessDescriptor{
		ID:                   "descriptor:tenant-alpha-document-reader",
		Profile:              api.CaringProfileCaring040RC2,
		SubjectType:          api.SubjectTypeGroup,
		OrganizationRelation: api.OrganizationRelationCustomer,
		CanonicalRole:        api.CanonicalRoleDoer,
		Scope: api.CaringScope{
			Level:    api.ScopeLevelResource,
			ID:       "document:internal-note",
			Tenant:   "tenant:alpha",
			Resource: "document:internal-note",
		},
		Planes:        []api.Plane{api.PlaneData},
		Capabilities:  []api.Capability{api.CapabilityView},
		ExposureModes: []api.ExposureMode{api.ExposureModeMasked, api.ExposureModePlaintext},
		Restrictions:  []api.Restriction{api.RestrictionExportBlocked},
	}
}

func assertObject(t *testing.T, snapshot topaz.DirectorySnapshot, objectType, objectID string) {
	t.Helper()
	for _, object := range snapshot.Objects {
		if object.Type == objectType && object.ID == objectID {
			return
		}
	}
	t.Fatalf("object %s:%s not found in %+v", objectType, objectID, snapshot.Objects)
}

func assertRelation(t *testing.T, snapshot topaz.DirectorySnapshot, want topaz.DirectoryRelation) {
	t.Helper()
	assertWrittenRelation(t, snapshot.Relations, want)
}

func assertWrittenRelation(t *testing.T, relations []topaz.DirectoryRelation, want topaz.DirectoryRelation) {
	t.Helper()
	for _, relation := range relations {
		if relation == want {
			return
		}
	}
	t.Fatalf("relation %+v not found in %+v", want, relations)
}

func contains(value, needle string) bool {
	return len(needle) == 0 || (len(value) >= len(needle) && stringsContains(value, needle))
}

func stringsContains(value, needle string) bool {
	for i := 0; i+len(needle) <= len(value); i++ {
		if value[i:i+len(needle)] == needle {
			return true
		}
	}
	return false
}

type fakeClient struct {
	checkResult topaz.CheckResult
	checkErr    error
	objects     []topaz.DirectoryObject
	relations   []topaz.DirectoryRelation
	bundleSink  topaz.FileBundleSink
}

func (c *fakeClient) Check(context.Context, topaz.DirectoryCheckRequest) (topaz.CheckResult, error) {
	return c.checkResult, c.checkErr
}

func (c *fakeClient) PutObject(_ context.Context, object topaz.DirectoryObject) error {
	c.objects = append(c.objects, object)
	return nil
}

func (c *fakeClient) PutRelation(_ context.Context, relation topaz.DirectoryRelation) (topaz.WriteResult, error) {
	c.relations = append(c.relations, relation)
	return topaz.WriteResult{ETag: "etag:last"}, nil
}

func (c *fakeClient) PutManifest(context.Context, []byte) error {
	return nil
}

func (c *fakeClient) PutPolicyBundle(ctx context.Context, bundle topaz.PolicyBundle) error {
	if c.bundleSink.Root == "" {
		return nil
	}
	return c.bundleSink.PutPolicyBundle(ctx, bundle)
}

func (c *fakeClient) Health(context.Context) error {
	return nil
}