package server

import (
	"context"
	"encoding/json"
	"errors"
	"net/http"
	"net/http/httptest"
	"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"
)

func assertErrorResponseContains(t *testing.T, res *httptest.ResponseRecorder, wantStatus int, want string) {
	t.Helper()
	if res.Code != wantStatus {
		t.Fatalf("expected %d, got %d: %s", wantStatus, res.Code, res.Body.String())
	}

	var payload map[string]string
	if err := json.Unmarshal(res.Body.Bytes(), &payload); err != nil {
		t.Fatalf("decode error response: %v", err)
	}

	if got := payload["error"]; !strings.Contains(got, want) {
		t.Fatalf("expected error containing %q, got %q", want, got)
	}
}

type backupTestKubeClient struct {
	*restoreTestKubeClient
	createBackupErr      error
	listBackupJobsPVCErr error
}

func (k *backupTestKubeClient) CreateBackupJob(ctx context.Context, cfg *config.Config, req api.BackupRequest) (string, string, error) {
	if k.createBackupErr != nil {
		return "", "", k.createBackupErr
	}
	return k.restoreTestKubeClient.fakeKubeClient.CreateBackupJob(ctx, cfg, req)
}

func (k *backupTestKubeClient) ListBackupJobsForPVC(ctx context.Context, namespace, pvc string) ([]k8s.BackupJobSummary, error) {
	if k.listBackupJobsPVCErr != nil {
		return nil, k.listBackupJobsPVCErr
	}
	return k.restoreTestKubeClient.fakeKubeClient.ListBackupJobsForPVC(ctx, namespace, pvc)
}

type backupTestLonghornClient struct {
	*restoreTestLonghornClient
	listBackups    []longhorn.Backup
	listBackupsErr error
	createSnapErr  error
	snapshotErr    error
}

func (l *backupTestLonghornClient) ListBackups(ctx context.Context, volumeName string) ([]longhorn.Backup, error) {
	if l.listBackupsErr != nil {
		return nil, l.listBackupsErr
	}
	if l.listBackups != nil {
		return l.listBackups, nil
	}
	return l.restoreTestLonghornClient.fakeLonghornClient.ListBackups(ctx, volumeName)
}

func (l *backupTestLonghornClient) CreateSnapshot(ctx context.Context, volume, name string, labels map[string]string) error {
	if l.createSnapErr != nil {
		return l.createSnapErr
	}
	return l.restoreTestLonghornClient.fakeLonghornClient.CreateSnapshot(ctx, volume, name, labels)
}

func (l *backupTestLonghornClient) SnapshotBackup(ctx context.Context, volume, name string, labels map[string]string, backupMode string) (*longhorn.Volume, error) {
	if l.snapshotErr != nil {
		return nil, l.snapshotErr
	}
	return l.restoreTestLonghornClient.fakeLonghornClient.SnapshotBackup(ctx, volume, name, labels, backupMode)
}

func newBackupTestServer(cfg *config.Config, client kubeClient, longhornClient longhornClient) *Server {
	return newRestoreTestServer(cfg, client, longhornClient)
}

func TestHandleInventoryRejectsUnsupportedMethodAndBackendError(t *testing.T) {
	srv := newBackupTestServer(
		&config.Config{AuthRequired: false, BackupDriver: "longhorn"},
		&backupTestKubeClient{restoreTestKubeClient: &restoreTestKubeClient{
			fakeKubeClient: &fakeKubeClient{},
			listPVCsErr:    errors.New("inventory exploded"),
		}},
		&backupTestLonghornClient{restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}}},
	)

	req := httptest.NewRequest(http.MethodPost, "/v1/inventory", nil)
	res := httptest.NewRecorder()
	srv.Handler().ServeHTTP(res, req)
	if res.Code != http.StatusMethodNotAllowed {
		t.Fatalf("expected 405, got %d: %s", res.Code, res.Body.String())
	}

	req = httptest.NewRequest(http.MethodGet, "/v1/inventory", nil)
	res = httptest.NewRecorder()
	srv.Handler().ServeHTTP(res, req)
	assertErrorResponseContains(t, res, http.StatusBadGateway, "inventory exploded")
}

func TestHandleBackupsRejectsInvalidRequestsAndBackendErrors(t *testing.T) {
	t.Run("invalid requests", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "longhorn"},
			&backupTestKubeClient{restoreTestKubeClient: &restoreTestKubeClient{
				fakeKubeClient: &fakeKubeClient{},
			}},
			&backupTestLonghornClient{restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}}},
		)

		req := httptest.NewRequest(http.MethodPost, "/v1/backups", nil)
		res := httptest.NewRecorder()
		srv.Handler().ServeHTTP(res, req)
		if res.Code != http.StatusMethodNotAllowed {
			t.Fatalf("expected 405, got %d: %s", res.Code, res.Body.String())
		}

		req = httptest.NewRequest(http.MethodGet, "/v1/backups", nil)
		res = httptest.NewRecorder()
		srv.Handler().ServeHTTP(res, req)
		assertErrorResponseContains(t, res, http.StatusBadRequest, "namespace and pvc are required")
	})

	t.Run("resolve pvc error", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "longhorn"},
			&backupTestKubeClient{restoreTestKubeClient: &restoreTestKubeClient{
				fakeKubeClient: &fakeKubeClient{},
				resolveErr:     errors.New("resolve backup pvc exploded"),
			}},
			&backupTestLonghornClient{restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}}},
		)
		req := httptest.NewRequest(http.MethodGet, "/v1/backups?namespace=apps&pvc=data", nil)
		res := httptest.NewRecorder()
		srv.Handler().ServeHTTP(res, req)
		assertErrorResponseContains(t, res, http.StatusBadRequest, "resolve backup pvc exploded")
	})

	t.Run("longhorn backend error", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "longhorn"},
			&backupTestKubeClient{restoreTestKubeClient: &restoreTestKubeClient{fakeKubeClient: &fakeKubeClient{}}},
			&backupTestLonghornClient{
				restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}},
				listBackupsErr:            errors.New("list backups exploded"),
			},
		)
		req := httptest.NewRequest(http.MethodGet, "/v1/backups?namespace=apps&pvc=data", nil)
		res := httptest.NewRecorder()
		srv.Handler().ServeHTTP(res, req)
		assertErrorResponseContains(t, res, http.StatusBadGateway, "list backups exploded")
	})

	t.Run("restic backend error", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "restic"},
			&backupTestKubeClient{
				restoreTestKubeClient: &restoreTestKubeClient{fakeKubeClient: &fakeKubeClient{}},
				listBackupJobsPVCErr:  errors.New("list jobs exploded"),
			},
			&backupTestLonghornClient{restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}}},
		)
		req := httptest.NewRequest(http.MethodGet, "/v1/backups?namespace=apps&pvc=data", nil)
		res := httptest.NewRecorder()
		srv.Handler().ServeHTTP(res, req)
		assertErrorResponseContains(t, res, http.StatusBadGateway, "list jobs exploded")
	})

	t.Run("unsupported driver", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "mystery"},
			&backupTestKubeClient{restoreTestKubeClient: &restoreTestKubeClient{fakeKubeClient: &fakeKubeClient{}}},
			&backupTestLonghornClient{restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}}},
		)
		req := httptest.NewRequest(http.MethodGet, "/v1/backups?namespace=apps&pvc=data", nil)
		res := httptest.NewRecorder()
		srv.Handler().ServeHTTP(res, req)
		assertErrorResponseContains(t, res, http.StatusBadRequest, "unsupported backup driver")
	})
}

func TestBackupHandlersSuccessPaths(t *testing.T) {
	t.Run("inventory success", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "longhorn", BackupMaxAge: 24 * time.Hour},
			&backupTestKubeClient{restoreTestKubeClient: &restoreTestKubeClient{
				fakeKubeClient: &fakeKubeClient{
					pvcs: []k8s.PVCSummary{{Namespace: "apps", Name: "data", VolumeName: "pv-data", Phase: "Bound"}},
				},
			}},
			&backupTestLonghornClient{
				restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}},
				listBackups:               []longhorn.Backup{{Name: "backup-a", Created: time.Now().UTC().Format(time.RFC3339), State: "Completed", Size: "1Gi"}},
			},
		)

		req := httptest.NewRequest(http.MethodGet, "/v1/inventory", nil)
		res := httptest.NewRecorder()
		srv.Handler().ServeHTTP(res, req)
		if res.Code != http.StatusOK || !strings.Contains(res.Body.String(), `"namespaces"`) {
			t.Fatalf("expected inventory success, got %d %s", res.Code, res.Body.String())
		}
	})

	t.Run("backups success longhorn", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "longhorn"},
			&backupTestKubeClient{restoreTestKubeClient: &restoreTestKubeClient{fakeKubeClient: &fakeKubeClient{}}},
			&backupTestLonghornClient{
				restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}},
				listBackups:               []longhorn.Backup{{Name: "backup-a", SnapshotName: "snap-a", Created: "2026-04-20T00:00:00Z", State: "Completed", URL: "s3://bucket/a", Size: "1Gi"}},
			},
		)
		req := httptest.NewRequest(http.MethodGet, "/v1/backups?namespace=apps&pvc=data", nil)
		res := httptest.NewRecorder()
		srv.Handler().ServeHTTP(res, req)
		if res.Code != http.StatusOK || !strings.Contains(res.Body.String(), `"backup-a"`) {
			t.Fatalf("expected longhorn backups success, got %d %s", res.Code, res.Body.String())
		}
	})

	t.Run("backups success restic", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "restic", ResticRepository: "s3:https://repo/root"},
			&backupTestKubeClient{restoreTestKubeClient: &restoreTestKubeClient{fakeKubeClient: &fakeKubeClient{
				backupJobs: map[string][]k8s.BackupJobSummary{
					"apps/data": {{Name: "restic-job", Namespace: "apps", PVC: "data", State: "Completed", Repository: "s3:https://repo/root", CreatedAt: time.Now().UTC()}},
				},
			}}},
			&backupTestLonghornClient{restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}}},
		)
		req := httptest.NewRequest(http.MethodGet, "/v1/backups?namespace=apps&pvc=data", nil)
		res := httptest.NewRecorder()
		srv.Handler().ServeHTTP(res, req)
		if res.Code != http.StatusOK || !strings.Contains(res.Body.String(), `"restic-job"`) {
			t.Fatalf("expected restic backups success, got %d %s", res.Code, res.Body.String())
		}
	})

	t.Run("handle backup success", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "restic"},
			&backupTestKubeClient{restoreTestKubeClient: &restoreTestKubeClient{fakeKubeClient: &fakeKubeClient{}}},
			&backupTestLonghornClient{restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}}},
		)
		req := httptest.NewRequest(http.MethodPost, "/v1/backup", strings.NewReader(`{"namespace":"apps","pvc":"data","dry_run":true}`))
		req.Header.Set("Content-Type", "application/json")
		res := httptest.NewRecorder()
		srv.Handler().ServeHTTP(res, req)
		if res.Code != http.StatusOK || !strings.Contains(res.Body.String(), `"dry_run":true`) {
			t.Fatalf("expected backup success, got %d %s", res.Code, res.Body.String())
		}
	})

	t.Run("namespace backup success", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "restic"},
			&backupTestKubeClient{restoreTestKubeClient: &restoreTestKubeClient{fakeKubeClient: &fakeKubeClient{
				pvcs: []k8s.PVCSummary{
					{Namespace: "apps", Name: "alpha", VolumeName: "pv-alpha", Phase: "Bound"},
					{Namespace: "apps", Name: "beta", VolumeName: "pv-beta", Phase: "Bound"},
				},
			}}},
			&backupTestLonghornClient{restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}}},
		)
		req := httptest.NewRequest(http.MethodPost, "/v1/backup/namespace", strings.NewReader(`{"namespace":"apps","dry_run":true}`))
		req.Header.Set("Content-Type", "application/json")
		res := httptest.NewRecorder()
		srv.Handler().ServeHTTP(res, req)
		if res.Code != http.StatusOK || !strings.Contains(res.Body.String(), `"total":2`) || !strings.Contains(res.Body.String(), `"dry_run":true`) {
			t.Fatalf("expected namespace backup success, got %d %s", res.Code, res.Body.String())
		}
	})
}

func TestHandleBackupAndNamespaceBackupValidationPaths(t *testing.T) {
	t.Run("backup request validation", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "restic"},
			&backupTestKubeClient{restoreTestKubeClient: &restoreTestKubeClient{fakeKubeClient: &fakeKubeClient{}}},
			&backupTestLonghornClient{restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}}},
		)

		testCases := []struct {
			name string
			body string
			code int
			want string
		}{
			{name: "method", body: "", code: http.StatusMethodNotAllowed, want: "method not allowed"},
			{name: "invalid json", body: `{"namespace":`, code: http.StatusBadRequest, want: "invalid JSON"},
			{name: "missing namespace", body: `{"pvc":"data"}`, code: http.StatusBadRequest, want: "namespace and pvc are required"},
			{name: "invalid keep last", body: `{"namespace":"apps","pvc":"data","keep_last":-1}`, code: http.StatusBadRequest, want: "keep_last must be >="},
		}

		for _, tc := range testCases {
			method := http.MethodPost
			if tc.name == "method" {
				method = http.MethodGet
			}
			req := httptest.NewRequest(method, "/v1/backup", strings.NewReader(tc.body))
			if method == http.MethodPost {
				req.Header.Set("Content-Type", "application/json")
			}
			res := httptest.NewRecorder()
			srv.Handler().ServeHTTP(res, req)
			assertErrorResponseContains(t, res, tc.code, tc.want)
		}
	})

	t.Run("namespace backup validation and backend", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "restic"},
			&backupTestKubeClient{restoreTestKubeClient: &restoreTestKubeClient{
				fakeKubeClient: &fakeKubeClient{},
				listPVCsErr:    errors.New("list namespace pvc exploded"),
			}},
			&backupTestLonghornClient{restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}}},
		)

		testCases := []struct {
			name string
			body string
			code int
			want string
		}{
			{name: "invalid json", body: `{"namespace":`, code: http.StatusBadRequest, want: "invalid JSON"},
			{name: "missing namespace", body: `{}`, code: http.StatusBadRequest, want: "namespace is required"},
			{name: "invalid keep last", body: `{"namespace":"apps","keep_last":-1}`, code: http.StatusBadRequest, want: "keep_last must be >="},
			{name: "invalid namespace", body: `{"namespace":"Bad_Ns"}`, code: http.StatusBadRequest, want: "namespace must be a valid Kubernetes DNS-1123 label"},
			{name: "backend error", body: `{"namespace":"apps"}`, code: http.StatusBadGateway, want: "list namespace pvc exploded"},
		}

		for _, tc := range testCases {
			req := httptest.NewRequest(http.MethodPost, "/v1/backup/namespace", strings.NewReader(tc.body))
			req.Header.Set("Content-Type", "application/json")
			res := httptest.NewRecorder()
			srv.Handler().ServeHTTP(res, req)
			assertErrorResponseContains(t, res, tc.code, tc.want)
		}
	})
}

func TestExecuteBackupAndStatusHelpers(t *testing.T) {
	t.Run("validation error", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "longhorn"},
			&backupTestKubeClient{restoreTestKubeClient: &restoreTestKubeClient{fakeKubeClient: &fakeKubeClient{}}},
			&backupTestLonghornClient{restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}}},
		)
		_, result, err := srv.executeBackup(context.Background(), api.BackupRequest{}, "brad")
		if result != "validation_error" || err == nil {
			t.Fatalf("expected validation error, got result=%q err=%v", result, err)
		}
	})

	t.Run("longhorn resolve error", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "longhorn"},
			&backupTestKubeClient{restoreTestKubeClient: &restoreTestKubeClient{
				fakeKubeClient: &fakeKubeClient{},
				resolveErr:     errors.New("resolve backup pvc exploded"),
			}},
			&backupTestLonghornClient{restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}}},
		)
		_, result, err := srv.executeBackup(context.Background(), api.BackupRequest{Namespace: "apps", PVC: "data"}, "brad")
		if result != "validation_error" || err == nil || !strings.Contains(err.Error(), "resolve backup pvc exploded") {
			t.Fatalf("expected resolve error, got result=%q err=%v", result, err)
		}
	})

	t.Run("longhorn snapshot error", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "longhorn"},
			&backupTestKubeClient{restoreTestKubeClient: &restoreTestKubeClient{fakeKubeClient: &fakeKubeClient{}}},
			&backupTestLonghornClient{
				restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}},
				createSnapErr:             errors.New("create snapshot exploded"),
			},
		)
		_, result, err := srv.executeBackup(context.Background(), api.BackupRequest{Namespace: "apps", PVC: "data"}, "brad")
		if result != "backend_error" || err == nil || !strings.Contains(err.Error(), "create snapshot exploded") {
			t.Fatalf("expected snapshot backend error, got result=%q err=%v", result, err)
		}
	})

	t.Run("longhorn backup error", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "longhorn"},
			&backupTestKubeClient{restoreTestKubeClient: &restoreTestKubeClient{fakeKubeClient: &fakeKubeClient{}}},
			&backupTestLonghornClient{
				restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}},
				snapshotErr:               errors.New("snapshot backup exploded"),
			},
		)
		_, result, err := srv.executeBackup(context.Background(), api.BackupRequest{Namespace: "apps", PVC: "data"}, "brad")
		if result != "backend_error" || err == nil || !strings.Contains(err.Error(), "snapshot backup exploded") {
			t.Fatalf("expected backup backend error, got result=%q err=%v", result, err)
		}
	})

	t.Run("restic backend error", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "restic"},
			&backupTestKubeClient{
				restoreTestKubeClient: &restoreTestKubeClient{fakeKubeClient: &fakeKubeClient{}},
				createBackupErr:       errors.New("create backup job exploded"),
			},
			&backupTestLonghornClient{restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}}},
		)
		_, result, err := srv.executeBackup(context.Background(), api.BackupRequest{Namespace: "apps", PVC: "data"}, "brad")
		if result != "backend_error" || err == nil || !strings.Contains(err.Error(), "create backup job exploded") {
			t.Fatalf("expected restic backend error, got result=%q err=%v", result, err)
		}
	})

	t.Run("unsupported driver", func(t *testing.T) {
		srv := newBackupTestServer(
			&config.Config{AuthRequired: false, BackupDriver: "mystery"},
			&backupTestKubeClient{restoreTestKubeClient: &restoreTestKubeClient{fakeKubeClient: &fakeKubeClient{}}},
			&backupTestLonghornClient{restoreTestLonghornClient: &restoreTestLonghornClient{fakeLonghornClient: &fakeLonghornClient{}}},
		)
		_, result, err := srv.executeBackup(context.Background(), api.BackupRequest{Namespace: "apps", PVC: "data"}, "brad")
		if result != "unsupported_driver" || err == nil || !strings.Contains(err.Error(), "unsupported backup driver") {
			t.Fatalf("expected unsupported driver error, got result=%q err=%v", result, err)
		}
	})

	t.Run("status helpers", func(t *testing.T) {
		testCases := map[string]int{
			"validation_error":   http.StatusBadRequest,
			"unsupported_driver": http.StatusBadRequest,
			"backend_error":      http.StatusBadGateway,
			"other":              http.StatusInternalServerError,
		}
		for result, want := range testCases {
			if got := backupStatusCode(result); got != want {
				t.Fatalf("backupStatusCode(%q): expected %d, got %d", result, want, got)
			}
		}

		if got := namespaceResultStatus(true, 2, 2, 0); got != "dry_run" {
			t.Fatalf("expected dry_run namespace result, got %q", got)
		}
		if got := namespaceResultStatus(false, 0, 0, 0); got != "empty" {
			t.Fatalf("expected empty namespace result, got %q", got)
		}
		if got := namespaceResultStatus(false, 2, 2, 0); got != "success" {
			t.Fatalf("expected success namespace result, got %q", got)
		}
		if got := namespaceResultStatus(false, 2, 0, 2); got != "failed" {
			t.Fatalf("expected failed namespace result, got %q", got)
		}
		if got := namespaceResultStatus(false, 2, 1, 1); got != "partial" {
			t.Fatalf("expected partial namespace result, got %q", got)
		}
	})
}