package server

import (
	"context"
	"errors"
	"testing"
	"time"

	"scm.bstein.dev/bstein/soteria/internal/api"
	"scm.bstein.dev/bstein/soteria/internal/config"
	"scm.bstein.dev/bstein/soteria/internal/k8s"
	"scm.bstein.dev/bstein/soteria/internal/longhorn"
)

type inventoryTestKubeClient struct {
	*fakeKubeClient
	listPVCsErr       error
	listBackupJobsErr map[string]error
}

func (k *inventoryTestKubeClient) ListBoundPVCs(ctx context.Context) ([]k8s.PVCSummary, error) {
	if k.listPVCsErr != nil {
		return nil, k.listPVCsErr
	}
	return k.fakeKubeClient.ListBoundPVCs(ctx)
}

func (k *inventoryTestKubeClient) ListBackupJobs(ctx context.Context, namespace string) ([]k8s.BackupJobSummary, error) {
	if err := k.listBackupJobsErr[namespace]; err != nil {
		return nil, err
	}
	return k.fakeKubeClient.ListBackupJobs(ctx, namespace)
}

type inventoryTestLonghornClient struct {
	*fakeLonghornClient
	listBackupsByVolume map[string][]longhorn.Backup
	listBackupsErr      map[string]error
}

func (l *inventoryTestLonghornClient) ListBackups(ctx context.Context, volumeName string) ([]longhorn.Backup, error) {
	if err := l.listBackupsErr[volumeName]; err != nil {
		return nil, err
	}
	if backups, ok := l.listBackupsByVolume[volumeName]; ok {
		return backups, nil
	}
	return l.fakeLonghornClient.ListBackups(ctx, volumeName)
}

func newInventoryTestServer(cfg *config.Config, client kubeClient, longhornClient longhornClient) *Server {
	return &Server{
		cfg:      cfg,
		client:   client,
		longhorn: longhornClient,
		metrics:  newTelemetry(),
	}
}

func TestBuildInventoryLonghornSortsNamespacesAndCalculatesHealth(t *testing.T) {
	now := time.Now().UTC()
	recent := now.Add(-2 * time.Hour)
	old := now.Add(-48 * time.Hour)

	client := &inventoryTestKubeClient{
		fakeKubeClient: &fakeKubeClient{
			pvcs: []k8s.PVCSummary{
				{Namespace: "zeta", Name: "cache", VolumeName: "vol-cache", Phase: "Bound", StorageClass: "fast", Capacity: "10Gi", AccessModes: []string{"ReadWriteOnce"}},
				{Namespace: "apps", Name: "data", VolumeName: "vol-data", Phase: "Bound", StorageClass: "fast", Capacity: "20Gi", AccessModes: []string{"ReadWriteOnce"}},
			},
		},
	}
	longhornClient := &inventoryTestLonghornClient{
		fakeLonghornClient: &fakeLonghornClient{},
		listBackupsByVolume: map[string][]longhorn.Backup{
			"vol-data": {
				{Name: "backup-new", Created: recent.Format(time.RFC3339), State: "Completed", Size: "2147483648"},
				{Name: "backup-old", Created: old.Format(time.RFC3339), State: "Completed", Size: "1073741824"},
			},
			"vol-cache": {},
		},
	}
	srv := newInventoryTestServer(&config.Config{
		BackupDriver: "longhorn",
		BackupMaxAge: 24 * time.Hour,
	}, client, longhornClient)

	inventory, err := srv.buildInventory(context.Background())
	if err != nil {
		t.Fatalf("build longhorn inventory: %v", err)
	}
	if len(inventory.Namespaces) != 2 {
		t.Fatalf("expected two namespaces, got %#v", inventory.Namespaces)
	}
	if inventory.Namespaces[0].Name != "apps" || inventory.Namespaces[1].Name != "zeta" {
		t.Fatalf("expected sorted namespaces, got %#v", inventory.Namespaces)
	}

	appsPVC := inventory.Namespaces[0].PVCs[0]
	if !appsPVC.Healthy || appsPVC.HealthReason != "fresh" {
		t.Fatalf("expected healthy fresh apps pvc, got %#v", appsPVC)
	}
	if appsPVC.BackupCount != 2 || appsPVC.CompletedBackups != 2 {
		t.Fatalf("expected completed backup counts, got %#v", appsPVC)
	}
	if appsPVC.LastBackupSizeBytes != 2147483648 || appsPVC.TotalBackupSizeBytes != 3221225472 {
		t.Fatalf("expected longhorn byte totals, got %#v", appsPVC)
	}
	if appsPVC.LastBackupAt == "" || appsPVC.LastBackupAgeHours <= 0 {
		t.Fatalf("expected latest backup timestamp, got %#v", appsPVC)
	}

	cachePVC := inventory.Namespaces[1].PVCs[0]
	if cachePVC.Healthy || cachePVC.HealthReason != "missing" {
		t.Fatalf("expected missing backup health, got %#v", cachePVC)
	}
}

func TestEnrichPVCInventoryCoversLonghornAndResticBranches(t *testing.T) {
	now := time.Now().UTC()
	recent := now.Add(-1 * time.Hour)
	old := now.Add(-72 * time.Hour)

	t.Run("longhorn branches", func(t *testing.T) {
		srv := newInventoryTestServer(&config.Config{
			BackupDriver: "longhorn",
			BackupMaxAge: 24 * time.Hour,
		}, &inventoryTestKubeClient{fakeKubeClient: &fakeKubeClient{}}, &inventoryTestLonghornClient{
			fakeLonghornClient: &fakeLonghornClient{},
			listBackupsErr: map[string]error{
				"vol-error": errors.New("list backups exploded"),
			},
			listBackupsByVolume: map[string][]longhorn.Backup{
				"vol-no-completed": {
					{Name: "backup-pending", Created: recent.Format(time.RFC3339), State: "InProgress"},
				},
				"vol-bad-time": {
					{Name: "backup-complete", Created: "not-a-time", State: "Completed", Size: "123"},
				},
				"vol-stale": {
					{Name: "backup-old", Created: old.Format(time.RFC3339), State: "Completed", Size: "10"},
				},
			},
		})

		testCases := []struct {
			entry apiPVCInventory
			want  string
			ok    bool
			err   string
		}{
			{entry: apiPVCInventory{Namespace: "apps", PVC: "err", Volume: "vol-error"}, want: "lookup_failed", ok: false, err: "list backups exploded"},
			{entry: apiPVCInventory{Namespace: "apps", PVC: "none", Volume: "vol-no-completed"}, want: "no_completed", ok: false},
			{entry: apiPVCInventory{Namespace: "apps", PVC: "bad", Volume: "vol-bad-time"}, want: "unknown_timestamp", ok: false},
			{entry: apiPVCInventory{Namespace: "apps", PVC: "stale", Volume: "vol-stale"}, want: "stale", ok: false},
		}

		for _, tc := range testCases {
			entry := tc.entry.toAPI()
			srv.enrichPVCInventory(context.Background(), &entry, nil, nil)
			if entry.HealthReason != tc.want || entry.Healthy != tc.ok {
				t.Fatalf("%s/%s: expected %q healthy=%v, got %#v", entry.Namespace, entry.PVC, tc.want, tc.ok, entry)
			}
			if tc.err != "" && entry.Error != tc.err {
				t.Fatalf("%s/%s: expected error %q, got %#v", entry.Namespace, entry.PVC, tc.err, entry)
			}
		}
	})

	t.Run("restic branches", func(t *testing.T) {
		client := &inventoryTestKubeClient{
			fakeKubeClient: &fakeKubeClient{
				jobLogs: map[string]string{
					"apps/job-new": `{"message_type":"summary","data_added":2048}`,
					"apps/job-old": `{"message_type":"summary","data_added":1024}`,
				},
			},
		}
		srv := newInventoryTestServer(&config.Config{
			Namespace:       "atlas",
			UsageSecretName: "restic-usage",
			BackupDriver:    "restic",
			BackupMaxAge:    24 * time.Hour,
		}, client, &inventoryTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}})

		resticJobsByPVC := map[string][]k8s.BackupJobSummary{
			"apps/data": {
				{Name: "job-old", Namespace: "apps", PVC: "data", State: "Completed", CreatedAt: old, CompletionTime: old, KeepLast: 1},
				{Name: "job-new", Namespace: "apps", PVC: "data", State: "Completed", CreatedAt: recent, CompletionTime: recent, KeepLast: 1},
			},
			"apps/running": {
				{Name: "job-running", Namespace: "apps", PVC: "running", State: "Running", CreatedAt: recent},
			},
			"apps/bad-time": {
				{Name: "job-bad", Namespace: "apps", PVC: "bad-time", State: "Completed"},
			},
		}
		for key := range resticJobsByPVC {
			sortBackupJobsNewestFirst(resticJobsByPVC[key])
		}

		entry := apiPVCInventory{Namespace: "apps", PVC: "data", Volume: "vol-data"}.toAPI()
		srv.enrichPVCInventory(context.Background(), &entry, resticJobsByPVC, nil)
		if !entry.Healthy || entry.HealthReason != "fresh" {
			t.Fatalf("expected fresh restic pvc, got %#v", entry)
		}
		if entry.LastJobName != "job-new" || entry.BackupCount != 2 || entry.CompletedBackups != 2 {
			t.Fatalf("expected sorted restic jobs, got %#v", entry)
		}
		if entry.LastBackupSizeBytes != 2048 || entry.TotalBackupSizeBytes != 2048 {
			t.Fatalf("expected retained size accounting, got %#v", entry)
		}

		running := apiPVCInventory{Namespace: "apps", PVC: "running", Volume: "vol-running"}.toAPI()
		srv.enrichPVCInventory(context.Background(), &running, resticJobsByPVC, nil)
		if running.Healthy || running.HealthReason != "in_progress" || running.ActiveBackups != 1 {
			t.Fatalf("expected in-progress restic pvc, got %#v", running)
		}

		missing := apiPVCInventory{Namespace: "apps", PVC: "missing", Volume: "vol-missing"}.toAPI()
		srv.enrichPVCInventory(context.Background(), &missing, resticJobsByPVC, nil)
		if missing.Healthy || missing.HealthReason != "missing" {
			t.Fatalf("expected missing restic pvc, got %#v", missing)
		}

		badTime := apiPVCInventory{Namespace: "apps", PVC: "bad-time", Volume: "vol-bad-time"}.toAPI()
		srv.enrichPVCInventory(context.Background(), &badTime, resticJobsByPVC, nil)
		if badTime.Healthy || badTime.HealthReason != "unknown_timestamp" {
			t.Fatalf("expected unknown timestamp restic pvc, got %#v", badTime)
		}

		lookupFailed := apiPVCInventory{Namespace: "ops", PVC: "data", Volume: "vol-ops"}.toAPI()
		srv.enrichPVCInventory(context.Background(), &lookupFailed, resticJobsByPVC, map[string]error{"ops": errors.New("list jobs exploded")})
		if lookupFailed.Healthy || lookupFailed.HealthReason != "lookup_failed" || lookupFailed.Error != "list jobs exploded" {
			t.Fatalf("expected lookup failure restic pvc, got %#v", lookupFailed)
		}
	})
}

func TestRefreshTelemetryRecordsSuccessAndFailure(t *testing.T) {
	successClient := &inventoryTestKubeClient{
		fakeKubeClient: &fakeKubeClient{
			pvcs: []k8s.PVCSummary{
				{Namespace: "apps", Name: "data", VolumeName: "vol-data", Phase: "Bound"},
			},
		},
	}
	successLonghorn := &inventoryTestLonghornClient{
		fakeLonghornClient: &fakeLonghornClient{},
		listBackupsByVolume: map[string][]longhorn.Backup{
			"vol-data": {
				{Name: "backup-new", Created: time.Now().UTC().Add(-1 * time.Hour).Format(time.RFC3339), State: "Completed", Size: "512"},
			},
		},
	}
	srv := newInventoryTestServer(&config.Config{
		BackupDriver: "longhorn",
		BackupMaxAge: 24 * time.Hour,
	}, successClient, successLonghorn)

	srv.refreshTelemetry(context.Background())
	if srv.metrics.inventoryRefreshFailure != 0 {
		t.Fatalf("expected successful refresh, got failure count %f", srv.metrics.inventoryRefreshFailure)
	}
	if srv.metrics.inventoryRefreshTime == 0 {
		t.Fatalf("expected inventory refresh timestamp to be recorded")
	}
	if len(srv.metrics.pvcBackupHealth) != 1 || len(srv.metrics.pvcBackupCount) != 1 {
		t.Fatalf("expected pvc metrics to be recorded, got health=%d count=%d", len(srv.metrics.pvcBackupHealth), len(srv.metrics.pvcBackupCount))
	}

	failingSrv := newInventoryTestServer(&config.Config{
		BackupDriver: "longhorn",
		BackupMaxAge: 24 * time.Hour,
	}, &inventoryTestKubeClient{
		fakeKubeClient: &fakeKubeClient{},
		listPVCsErr:    errors.New("inventory exploded"),
	}, &inventoryTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}})

	failingSrv.refreshTelemetry(context.Background())
	if failingSrv.metrics.inventoryRefreshFailure != 1 {
		t.Fatalf("expected failed refresh metric, got %f", failingSrv.metrics.inventoryRefreshFailure)
	}
}

func TestSortBackupJobsNewestFirstUsesCompletionCreatedAndNameTiebreakers(t *testing.T) {
	now := time.Now().UTC()
	items := []k8s.BackupJobSummary{
		{
			Name:           "job-a",
			Namespace:      "apps",
			PVC:            "data",
			CreatedAt:      now.Add(-3 * time.Hour),
			CompletionTime: now.Add(-2 * time.Hour),
		},
		{
			Name:      "job-c",
			Namespace: "apps",
			PVC:       "data",
			CreatedAt: now.Add(-1 * time.Hour),
		},
		{
			Name:           "job-b",
			Namespace:      "apps",
			PVC:            "data",
			CreatedAt:      now.Add(-4 * time.Hour),
			CompletionTime: now.Add(-2 * time.Hour),
		},
	}

	sortBackupJobsNewestFirst(items)

	got := []string{items[0].Name, items[1].Name, items[2].Name}
	want := []string{"job-c", "job-b", "job-a"}
	for index := range want {
		if got[index] != want[index] {
			t.Fatalf("expected sorted names %v, got %v", want, got)
		}
	}
}

type apiPVCInventory struct {
	Namespace string
	PVC       string
	Volume    string
}

func (p apiPVCInventory) toAPI() api.PVCInventory {
	return api.PVCInventory{
		Namespace: p.Namespace,
		PVC:       p.PVC,
		Volume:    p.Volume,
	}
}