package server

import (
	"context"
	"errors"
	"strings"
	"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 policyCycleTestKubeClient struct {
	*inventoryTestKubeClient
	createBackupErrForPVC map[string]error
	backupRequests        []api.BackupRequest
}

func (k *policyCycleTestKubeClient) CreateBackupJob(ctx context.Context, cfg *config.Config, req api.BackupRequest) (string, string, error) {
	k.backupRequests = append(k.backupRequests, req)
	if err := k.createBackupErrForPVC[req.PVC]; err != nil {
		return "", "", err
	}
	return k.inventoryTestKubeClient.fakeKubeClient.CreateBackupJob(ctx, cfg, req)
}

func metricCount(samples map[string]metricSample, labels map[string]string) float64 {
	sample, ok := samples[metricKey(labels)]
	if !ok {
		return 0
	}
	return sample.value
}

func findBackupRequestByPVC(items []api.BackupRequest, pvc string) (api.BackupRequest, bool) {
	for _, item := range items {
		if item.PVC == pvc {
			return item, true
		}
	}
	return api.BackupRequest{}, false
}

func TestRunPolicyCycleCoversInventoryErrorAndConcurrentGuard(t *testing.T) {
	client := &policyCycleTestKubeClient{
		inventoryTestKubeClient: &inventoryTestKubeClient{
			fakeKubeClient: &fakeKubeClient{},
			listPVCsErr:    errors.New("inventory exploded"),
		},
	}
	srv := &Server{
		cfg: &config.Config{
			BackupDriver:       "restic",
			BackupMaxAge:       24 * time.Hour,
			PolicyEvalInterval: time.Minute,
		},
		client:   client,
		longhorn: &fakeLonghornClient{},
		metrics:  newTelemetry(),
		policies: map[string]api.BackupPolicy{
			"apps__all": {ID: "apps__all", Namespace: "apps", IntervalHours: 6, Enabled: true, Dedupe: true},
		},
	}

	srv.runPolicyCycle(context.Background())
	if got := metricCount(srv.metrics.policyBackups, map[string]string{"result": "inventory_error"}); got != 1 {
		t.Fatalf("expected inventory_error policy metric, got %f", got)
	}
	if srv.running {
		t.Fatalf("expected policy runner lock to be released after inventory failure")
	}

	srv.running = true
	srv.runPolicyCycle(context.Background())
	if got := metricCount(srv.metrics.policyBackups, map[string]string{"result": "inventory_error"}); got != 1 {
		t.Fatalf("expected concurrent guard to skip second run, got %f", got)
	}
}

func TestRunPolicyCycleCoversEffectivePoliciesAndResultTracking(t *testing.T) {
	now := time.Now().UTC()
	recent := now.Add(-30 * time.Minute)
	client := &policyCycleTestKubeClient{
		inventoryTestKubeClient: &inventoryTestKubeClient{
			fakeKubeClient: &fakeKubeClient{
				pvcs: []k8s.PVCSummary{
					{Namespace: "apps", Name: "data", VolumeName: "vol-data", Phase: "Bound"},
					{Namespace: "apps", Name: "busy", VolumeName: "vol-busy", Phase: "Bound"},
					{Namespace: "apps", Name: "recent", VolumeName: "vol-recent", Phase: "Bound"},
					{Namespace: "apps", Name: "attempted", VolumeName: "vol-attempted", Phase: "Bound"},
					{Namespace: "apps", Name: "fail", VolumeName: "vol-fail", Phase: "Bound"},
				},
				backupJobs: map[string][]k8s.BackupJobSummary{
					"apps/busy": {
						{Name: "job-busy", Namespace: "apps", PVC: "busy", Repository: "s3:https://repo/root/isolated/apps/busy", State: "Running", CreatedAt: recent},
					},
					"apps/recent": {
						{Name: "job-recent", Namespace: "apps", PVC: "recent", State: "Completed", CreatedAt: recent, CompletionTime: recent, KeepLast: 1},
					},
					"apps/attempted": {
						{Name: "job-attempted", Namespace: "apps", PVC: "attempted", State: "Failed", CreatedAt: recent, KeepLast: 1},
					},
				},
			},
		},
		createBackupErrForPVC: map[string]error{
			"fail": errors.New("create backup job exploded"),
		},
	}
	srv := &Server{
		cfg: &config.Config{
			BackupDriver:     "restic",
			BackupMaxAge:     24 * time.Hour,
			ResticRepository: "s3:https://repo/root",
		},
		client:   client,
		longhorn: &fakeLonghornClient{},
		metrics:  newTelemetry(),
		policies: map[string]api.BackupPolicy{
			"apps__all":      {ID: "apps__all", Namespace: "apps", IntervalHours: 6, Enabled: true, Dedupe: true, KeepLast: 1},
			"apps__data":     {ID: "apps__data", Namespace: "apps", PVC: "data", IntervalHours: 1, Enabled: true, Dedupe: false, KeepLast: 2},
			"apps__disabled": {ID: "apps__disabled", Namespace: "apps", PVC: "disabled", IntervalHours: 1, Enabled: false, Dedupe: false, KeepLast: 5},
		},
	}

	srv.runPolicyCycle(context.Background())

	if len(client.backupRequests) != 2 {
		t.Fatalf("expected two executed backup requests, got %#v", client.backupRequests)
	}
	dataReq, ok := findBackupRequestByPVC(client.backupRequests, "data")
	if !ok || dataReq.Dedupe == nil || *dataReq.Dedupe != false || dataReq.KeepLast == nil || *dataReq.KeepLast != 2 {
		t.Fatalf("expected stricter PVC policy to win for data, got %#v", client.backupRequests)
	}

	if got := metricCount(srv.metrics.policyBackups, map[string]string{"result": "success"}); got != 1 {
		t.Fatalf("expected one successful policy backup, got %f", got)
	}
	if got := metricCount(srv.metrics.policyBackups, map[string]string{"result": "backend_error"}); got != 1 {
		t.Fatalf("expected one backend error policy backup, got %f", got)
	}
	if got := metricCount(srv.metrics.policyBackups, map[string]string{"result": "in_progress"}); got != 1 {
		t.Fatalf("expected one in-progress policy backup, got %f", got)
	}
	if got := metricCount(srv.metrics.policyBackups, map[string]string{"result": "not_due"}); got != 2 {
		t.Fatalf("expected two not-due policy backups, got %f", got)
	}

	if got := metricCount(srv.metrics.backupRequests, map[string]string{"driver": "restic", "result": "success"}); got != 1 {
		t.Fatalf("expected one successful executed backup request, got %f", got)
	}
	if got := metricCount(srv.metrics.backupRequests, map[string]string{"driver": "restic", "result": "backend_error"}); got != 1 {
		t.Fatalf("expected one failed executed backup request, got %f", got)
	}
}

func TestRunPolicyCycleHonorsBackupLimit(t *testing.T) {
	client := &policyCycleTestKubeClient{
		inventoryTestKubeClient: &inventoryTestKubeClient{
			fakeKubeClient: &fakeKubeClient{
				pvcs: []k8s.PVCSummary{
					{Namespace: "apps", Name: "alpha", VolumeName: "vol-alpha", Phase: "Bound"},
					{Namespace: "apps", Name: "beta", VolumeName: "vol-beta", Phase: "Bound"},
				},
			},
		},
	}
	srv := &Server{
		cfg: &config.Config{
			BackupDriver:          "restic",
			BackupMaxAge:          24 * time.Hour,
			ResticRepository:      "s3:https://repo/root",
			PolicyBackupsPerCycle: 1,
		},
		client:   client,
		longhorn: &fakeLonghornClient{},
		metrics:  newTelemetry(),
		policies: map[string]api.BackupPolicy{
			"apps__all": {ID: "apps__all", Namespace: "apps", IntervalHours: 1, Enabled: true, Dedupe: true},
		},
	}

	srv.runPolicyCycle(context.Background())

	if len(client.backupRequests) != 1 {
		t.Fatalf("expected one policy backup due to cycle limit, got %#v", client.backupRequests)
	}
	if client.backupRequests[0].PVC != "alpha" {
		t.Fatalf("expected deterministic first backup for alpha, got %#v", client.backupRequests[0])
	}
	if got := metricCount(srv.metrics.policyBackups, map[string]string{"result": "cycle_limit"}); got != 1 {
		t.Fatalf("expected cycle_limit metric, got %f", got)
	}
}

func TestRunPolicyCycleSkipsExcludedPVCsAndBusyRepositories(t *testing.T) {
	client := &policyCycleTestKubeClient{
		inventoryTestKubeClient: &inventoryTestKubeClient{
			fakeKubeClient: &fakeKubeClient{
				pvcs: []k8s.PVCSummary{
					{Namespace: "apps", Name: "data", VolumeName: "vol-data", Phase: "Bound", StorageClass: "astreae"},
					{Namespace: "apps", Name: "cache", VolumeName: "vol-cache", Phase: "Bound", StorageClass: "local-path"},
				},
				backupJobs: map[string][]k8s.BackupJobSummary{
					"apps/other": {
						{Name: "job-other", Namespace: "apps", PVC: "other", Repository: "s3:https://repo/root", State: "Running", CreatedAt: time.Now().UTC()},
					},
				},
			},
		},
	}
	srv := &Server{
		cfg: &config.Config{
			BackupDriver:           "restic",
			BackupMaxAge:           24 * time.Hour,
			ResticRepository:       "s3:https://repo/root",
			ExcludedStorageClasses: []string{"local-path"},
		},
		client:   client,
		longhorn: &fakeLonghornClient{},
		metrics:  newTelemetry(),
		policies: map[string]api.BackupPolicy{
			"apps__all": {ID: "apps__all", Namespace: "apps", IntervalHours: 1, Enabled: true, Dedupe: true},
		},
	}

	srv.runPolicyCycle(context.Background())

	if len(client.backupRequests) != 0 {
		t.Fatalf("expected no backup requests while shared repo is busy and cache is excluded, got %#v", client.backupRequests)
	}
	if got := metricCount(srv.metrics.policyBackups, map[string]string{"result": "repo_in_progress"}); got != 1 {
		t.Fatalf("expected repo_in_progress metric, got %f", got)
	}
	if got := metricCount(srv.metrics.policyBackups, map[string]string{"result": "excluded"}); got != 1 {
		t.Fatalf("expected excluded metric, got %f", got)
	}
}

func TestRunPolicyCycleSkipsLiveExclusivePVCs(t *testing.T) {
	client := &policyCycleTestKubeClient{
		inventoryTestKubeClient: &inventoryTestKubeClient{
			fakeKubeClient: &fakeKubeClient{
				pvcs: []k8s.PVCSummary{
					{Namespace: "apps", Name: "data", VolumeName: "vol-data", Phase: "Bound", AccessModes: []string{"ReadWriteOnce"}},
					{Namespace: "apps", Name: "shared", VolumeName: "vol-shared", Phase: "Bound", AccessModes: []string{"ReadWriteMany"}},
				},
				pvcMounts: map[string][]k8s.PVCMount{
					"apps/data":   {{PodName: "gitea-0", NodeName: "titan-06", Phase: "Running"}},
					"apps/shared": {{PodName: "web-0", NodeName: "titan-07", Phase: "Running"}},
				},
			},
		},
	}
	srv := &Server{
		cfg: &config.Config{
			BackupDriver:     "restic",
			BackupMaxAge:     24 * time.Hour,
			ResticRepository: "s3:https://repo/root",
		},
		client:   client,
		longhorn: &fakeLonghornClient{},
		metrics:  newTelemetry(),
		policies: map[string]api.BackupPolicy{
			"apps__all": {ID: "apps__all", Namespace: "apps", IntervalHours: 1, Enabled: true, Dedupe: true},
		},
	}

	srv.runPolicyCycle(context.Background())

	if len(client.backupRequests) != 1 || client.backupRequests[0].PVC != "shared" {
		t.Fatalf("expected only RWX pvc backup request, got %#v", client.backupRequests)
	}
	if got := metricCount(srv.metrics.policyBackups, map[string]string{"result": "live_rwo_mount"}); got != 1 {
		t.Fatalf("expected live_rwo_mount skip metric, got %f", got)
	}
	if got := metricCount(srv.metrics.policyBackups, map[string]string{"result": "success"}); got != 1 {
		t.Fatalf("expected one successful policy backup, got %f", got)
	}
}

func TestRunPolicyCycleSkipsDetachedLonghornVolumesWithoutConsumingLimit(t *testing.T) {
	client := &policyCycleTestKubeClient{
		inventoryTestKubeClient: &inventoryTestKubeClient{
			fakeKubeClient: &fakeKubeClient{
				pvcs: []k8s.PVCSummary{
					{Namespace: "apps", Name: "detached", VolumeName: "vol-detached", Phase: "Bound"},
					{Namespace: "apps", Name: "ready", VolumeName: "vol-ready", Phase: "Bound"},
				},
			},
		},
	}
	longhornClient := &fakeLonghornClient{
		volumes: map[string]longhorn.Volume{
			"vol-detached": {Name: "vol-detached", State: "detached"},
			"vol-ready":    {Name: "vol-ready", State: "attached"},
		},
	}
	srv := &Server{
		cfg: &config.Config{
			BackupDriver:          "longhorn",
			BackupMaxAge:          24 * time.Hour,
			PolicyBackupsPerCycle: 1,
		},
		client:   client,
		longhorn: longhornClient,
		metrics:  newTelemetry(),
		policies: map[string]api.BackupPolicy{
			"apps__all": {ID: "apps__all", Namespace: "apps", IntervalHours: 1, Enabled: true, Dedupe: true},
		},
	}

	srv.runPolicyCycle(context.Background())

	if longhornClient.createSnapshotName == "" || !strings.Contains(longhornClient.createSnapshotName, "apps-ready") {
		t.Fatalf("expected ready volume snapshot backup after detached skip, got snapshot %q", longhornClient.createSnapshotName)
	}
	if got := metricCount(srv.metrics.policyBackups, map[string]string{"result": "volume_not_ready"}); got != 1 {
		t.Fatalf("expected volume_not_ready metric, got %f", got)
	}
	if got := metricCount(srv.metrics.policyBackups, map[string]string{"result": "success"}); got != 1 {
		t.Fatalf("expected one successful policy backup, got %f", got)
	}
}