package legacy

import (
	"context"
	"database/sql"
	"encoding/json"
	"fmt"
	"strconv"
	"strings"
	"sync"
	"time"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/utils/ptr"

	claims "github.com/grafana/authlib/types"
	dashboardOG "github.com/grafana/grafana/apps/dashboard/pkg/apis/dashboard"
	dashboardV0 "github.com/grafana/grafana/apps/dashboard/pkg/apis/dashboard/v0alpha1"
	dashboardV1 "github.com/grafana/grafana/apps/dashboard/pkg/apis/dashboard/v1beta1"
	"github.com/grafana/grafana/apps/dashboard/pkg/migration/schemaversion"
	"github.com/grafana/grafana/pkg/apimachinery/apis/common/v0alpha1"
	"github.com/grafana/grafana/pkg/apimachinery/identity"
	"github.com/grafana/grafana/pkg/apimachinery/utils"
	"github.com/grafana/grafana/pkg/components/simplejson"
	"github.com/grafana/grafana/pkg/infra/log"
	"github.com/grafana/grafana/pkg/registry/apis/dashboard/legacysearcher"
	"github.com/grafana/grafana/pkg/services/apiserver/endpoints/request"
	gapiutil "github.com/grafana/grafana/pkg/services/apiserver/utils"
	"github.com/grafana/grafana/pkg/services/dashboards"
	"github.com/grafana/grafana/pkg/services/provisioning"
	"github.com/grafana/grafana/pkg/services/search/sort"
	"github.com/grafana/grafana/pkg/storage/legacysql"
	"github.com/grafana/grafana/pkg/storage/unified/resource"
	"github.com/grafana/grafana/pkg/storage/unified/sql/sqltemplate"
)

var (
	_ DashboardAccess = (*dashboardSqlAccess)(nil)
)

type dashboardRow struct {
	// The numeric version for this dashboard
	RV int64

	// Dashboard resource
	Dash *dashboardV1.Dashboard

	// The folder UID (needed for access control checks)
	FolderUID string

	// The token we can use that will start a new connection that includes
	// this same dashboard
	token *continueToken
}

type dashboardSqlAccess struct {
	sql          legacysql.LegacyDatabaseProvider
	namespacer   request.NamespaceMapper
	provisioning provisioning.ProvisioningService

	// Use for writing (not reading)
	dashStore             dashboards.Store
	dashboardSearchClient legacysearcher.DashboardSearchClient

	// Typically one... the server wrapper
	subscribers []chan *resource.WrittenEvent
	mutex       sync.Mutex
	log         log.Logger
}

func NewDashboardAccess(sql legacysql.LegacyDatabaseProvider,
	namespacer request.NamespaceMapper,
	dashStore dashboards.Store,
	provisioning provisioning.ProvisioningService,
	sorter sort.Service,
) DashboardAccess {
	dashboardSearchClient := legacysearcher.NewDashboardSearchClient(dashStore, sorter)
	return &dashboardSqlAccess{
		sql:                   sql,
		namespacer:            namespacer,
		dashStore:             dashStore,
		provisioning:          provisioning,
		dashboardSearchClient: *dashboardSearchClient,
		log:                   log.New("dashboard.legacysql"),
	}
}

func (a *dashboardSqlAccess) getRows(ctx context.Context, sql *legacysql.LegacyDatabaseHelper, query *DashboardQuery) (*rowsWrapper, error) {
	if len(query.Labels) > 0 {
		return nil, fmt.Errorf("labels not yet supported")
		// if query.Requirements.Folder != nil {
		// 	args = append(args, *query.Requirements.Folder)
		// 	sqlcmd = fmt.Sprintf("%s AND dashboard.folder_uid=?$%d", sqlcmd, len(args))
		// }
	}

	req := newQueryReq(sql, query)

	tmpl := sqlQueryDashboards
	if query.UseHistoryTable() && query.GetTrash {
		return nil, fmt.Errorf("trash not included in history table")
	}

	rawQuery, err := sqltemplate.Execute(tmpl, req)
	if err != nil {
		return nil, fmt.Errorf("execute template %q: %w", tmpl.Name(), err)
	}
	q := rawQuery
	// if false {
	// 	 pretty := sqltemplate.RemoveEmptyLines(rawQuery)
	//	 fmt.Printf("DASHBOARD QUERY: %s [%+v] // %+v\n", pretty, req.GetArgs(), query)
	// }

	rows, err := sql.DB.GetSqlxSession().Query(ctx, q, req.GetArgs()...)
	if err != nil {
		if rows != nil {
			_ = rows.Close()
		}
		rows = nil
	}
	return &rowsWrapper{
		rows:    rows,
		a:       a,
		history: query.GetHistory,
	}, err
}

var _ resource.ListIterator = (*rowsWrapper)(nil)

type rowsWrapper struct {
	a       *dashboardSqlAccess
	rows    *sql.Rows
	history bool
	count   int

	// Current
	row *dashboardRow
	err error

	// max 100 rejected?
	rejected []dashboardRow
}

func (a *dashboardSqlAccess) GetResourceStats(ctx context.Context, namespace string, minCount int) ([]resource.ResourceStats, error) {
	return nil, fmt.Errorf("not implemented")
}

func (r *rowsWrapper) Close() error {
	if r.rows == nil {
		return nil
	}
	return r.rows.Close()
}

func (r *rowsWrapper) Next() bool {
	if r.err != nil {
		return false
	}
	var err error

	// breaks after first readable value
	for r.rows.Next() {
		r.count++

		r.row, err = r.a.scanRow(r.rows, r.history)
		if err != nil {
			if len(r.rejected) > 1000 || r.row == nil {
				r.err = fmt.Errorf("too many rejected rows (%d) %w", len(r.rejected), err)
				return false
			}
			r.rejected = append(r.rejected, *r.row)
			continue
		}

		if r.row != nil {
			// returns the first visible dashboard
			return true
		}
	}
	return false
}

// ContinueToken implements resource.ListIterator.
func (r *rowsWrapper) ContinueToken() string {
	return r.row.token.String()
}

// ContinueTokenWithCurrentRV implements resource.ListIterator.
func (r *rowsWrapper) ContinueTokenWithCurrentRV() string {
	return r.row.token.String()
}

// Error implements resource.ListIterator.
func (r *rowsWrapper) Error() error {
	return r.err
}

// Name implements resource.ListIterator.
func (r *rowsWrapper) Name() string {
	return r.row.Dash.Name
}

// Namespace implements resource.ListIterator.
func (r *rowsWrapper) Namespace() string {
	return r.row.Dash.Namespace
}

// ResourceVersion implements resource.ListIterator.
func (r *rowsWrapper) ResourceVersion() int64 {
	return r.row.RV
}

func (r *rowsWrapper) Folder() string {
	return r.row.FolderUID
}

// Value implements resource.ListIterator.
func (r *rowsWrapper) Value() []byte {
	b, err := json.Marshal(r.row.Dash)
	r.err = err
	return b
}

func (a *dashboardSqlAccess) scanRow(rows *sql.Rows, history bool) (*dashboardRow, error) {
	dash := &dashboardV1.Dashboard{
		TypeMeta:   dashboardV1.DashboardResourceInfo.TypeMeta(),
		ObjectMeta: metav1.ObjectMeta{Annotations: make(map[string]string)},
	}
	row := &dashboardRow{Dash: dash}

	var dashboard_id int64
	var orgId int64
	var folder_uid sql.NullString
	var updated time.Time
	var updatedBy sql.NullString
	var updatedByID sql.NullInt64
	var deleted sql.NullTime

	var created time.Time
	var createdBy sql.NullString
	var createdByID sql.NullInt64
	var message sql.NullString
	var apiVersion sql.NullString

	var plugin_id sql.NullString
	var origin_name sql.NullString
	var origin_path sql.NullString
	var origin_ts sql.NullInt64
	var origin_hash sql.NullString
	var data []byte // the dashboard JSON
	var version int64

	err := rows.Scan(&orgId, &dashboard_id, &dash.Name, &folder_uid,
		&deleted, &plugin_id,
		&origin_name, &origin_path, &origin_hash, &origin_ts,
		&created, &createdBy, &createdByID,
		&updated, &updatedBy, &updatedByID,
		&version, &message, &data, &apiVersion,
	)
	switch apiVersion.String {
	case "":
		apiVersion.String = dashboardV0.VERSION // default value
	case "v1alpha1":
		apiVersion.String = dashboardV0.VERSION // downgrade to v0 (it may not have run migrations)
	}

	row.token = &continueToken{orgId: orgId, id: dashboard_id}
	// when listing from the history table, we want to use the version as the ID to continue from
	if history {
		row.token.id = version
	}
	if err == nil {
		row.RV = version
		dash.ResourceVersion = fmt.Sprintf("%d", row.RV)
		dash.Namespace = a.namespacer(orgId)
		dash.APIVersion = fmt.Sprintf("%s/%s", dashboardV1.GROUP, apiVersion.String)
		dash.UID = gapiutil.CalculateClusterWideUID(dash)
		dash.SetCreationTimestamp(metav1.NewTime(created))
		meta, err := utils.MetaAccessor(dash)
		if err != nil {
			return nil, err
		}
		meta.SetUpdatedTimestamp(&updated)
		meta.SetCreatedBy(getUserID(createdBy, createdByID))
		meta.SetUpdatedBy(getUserID(updatedBy, updatedByID))
		meta.SetDeprecatedInternalID(dashboard_id) //nolint:staticcheck
		meta.SetGeneration(version)

		if deleted.Valid {
			meta.SetDeletionTimestamp(ptr.To(metav1.NewTime(deleted.Time)))
			meta.SetGeneration(utils.DeletedGeneration)
		}

		if message.String != "" {
			if len(message.String) > 500 {
				message.String = message.String[0:490] + "..."
			}
			meta.SetMessage(message.String)
		}
		if folder_uid.String != "" {
			meta.SetFolder(folder_uid.String)
			row.FolderUID = folder_uid.String
		}

		if origin_name.String != "" {
			meta.SetSourceProperties(utils.SourceProperties{
				Path:            origin_path.String,
				Checksum:        origin_hash.String,
				TimestampMillis: origin_ts.Int64,
			})
			meta.SetManagerProperties(utils.ManagerProperties{
				Kind:     utils.ManagerKindClassicFP, // nolint:staticcheck
				Identity: origin_name.String,
			})
		} else if plugin_id.String != "" {
			meta.SetManagerProperties(utils.ManagerProperties{
				Kind:     utils.ManagerKindPlugin,
				Identity: plugin_id.String,
			})
		}

		if len(data) > 0 {
			err = dash.Spec.UnmarshalJSON(data)
			if err != nil {
				return row, fmt.Errorf("JSON unmarshal error for: %s // %w", dash.Name, err)
			}
		}
		// Ignore any saved values for id/version/uid
		delete(dash.Spec.Object, "id")
		delete(dash.Spec.Object, "version")
		delete(dash.Spec.Object, "uid")
	}
	return row, err
}

func getUserID(v sql.NullString, id sql.NullInt64) string {
	if v.Valid && v.String != "" {
		return claims.NewTypeID(claims.TypeUser, v.String)
	}
	if id.Valid && id.Int64 == -1 {
		return claims.NewTypeID(claims.TypeProvisioning, "")
	}
	return ""
}

// DeleteDashboard implements DashboardAccess.
func (a *dashboardSqlAccess) DeleteDashboard(ctx context.Context, orgId int64, uid string) (*dashboardV1.Dashboard, bool, error) {
	dash, _, err := a.GetDashboard(ctx, orgId, uid, 0)
	if err != nil {
		return nil, false, err
	}

	err = a.dashStore.DeleteDashboard(ctx, &dashboards.DeleteDashboardCommand{
		OrgID: orgId,
		UID:   uid,
	})
	if err != nil {
		return nil, false, err
	}
	return dash, true, nil
}

func (a *dashboardSqlAccess) buildSaveDashboardCommand(ctx context.Context, orgId int64, dash *dashboardV1.Dashboard) (*dashboards.SaveDashboardCommand, bool, error) {
	created := false
	user, ok := claims.AuthInfoFrom(ctx)
	if !ok || user == nil {
		return nil, created, fmt.Errorf("no user found in context")
	}

	if dash.Name != "" {
		dash.Spec.Set("uid", dash.Name)

		// Get the previous version to set the internal ID
		old, _ := a.dashStore.GetDashboard(ctx, &dashboards.GetDashboardQuery{
			OrgID: orgId,
			UID:   dash.Name,
		})
		if old != nil {
			dash.Spec.Set("id", old.ID)
			dash.Spec.Set("version", float64(old.Version))
		} else {
			dash.Spec.Remove("id") // existing of "id" makes it an update
			created = true
		}
	} else {
		dash.Spec.Remove("id")
		dash.Spec.Remove("uid")
	}

	var userID int64
	if claims.IsIdentityType(user.GetIdentityType(), claims.TypeUser) {
		var err error
		userID, err = identity.UserIdentifier(user.GetSubject())
		if err != nil {
			return nil, created, err
		}
	}

	apiVersion := strings.TrimPrefix(dash.APIVersion, dashboardV1.GROUP+"/")
	meta, err := utils.MetaAccessor(dash)
	if err != nil {
		return nil, created, err
	}

	// v1 should be saved as schema version 41. v0 allows for older versions
	if strings.HasPrefix(apiVersion, "v1") {
		schemaVersion := schemaversion.GetSchemaVersion(dash.Spec.Object)
		if schemaVersion < int(schemaversion.LATEST_VERSION) {
			apiVersion = dashboardV0.VERSION
			a.log.Info("Downgrading v1alpha1 dashboard to v0alpha1 due to schema version mismatch", "dashboard", dash.Name, "schema_version", schemaVersion)
		}
	}

	return &dashboards.SaveDashboardCommand{
		OrgID:      orgId,
		Message:    meta.GetMessage(),
		PluginID:   dashboardOG.GetPluginIDFromMeta(meta),
		Dashboard:  simplejson.NewFromAny(dash.Spec.UnstructuredContent()),
		FolderUID:  meta.GetFolder(),
		Overwrite:  true, // already passed the revisionVersion checks!
		UserID:     userID,
		APIVersion: apiVersion,
	}, created, nil
}

func (a *dashboardSqlAccess) SaveDashboard(ctx context.Context, orgId int64, dash *dashboardV1.Dashboard, failOnExisting bool) (*dashboardV1.Dashboard, bool, error) {
	user, ok := claims.AuthInfoFrom(ctx)
	if !ok || user == nil {
		return nil, false, fmt.Errorf("no user found in context")
	}

	cmd, created, err := a.buildSaveDashboardCommand(ctx, orgId, dash)
	if err != nil {
		return nil, created, err
	}
	if failOnExisting && !created {
		return nil, created, dashboards.ErrDashboardWithSameUIDExists
	}

	out, err := a.dashStore.SaveDashboard(ctx, *cmd)
	if err != nil {
		return nil, false, err
	}
	if out != nil {
		created = (out.Created.Unix() == out.Updated.Unix()) // and now?
	}
	dash, _, err = a.GetDashboard(ctx, orgId, out.UID, 0)
	if err != nil {
		return nil, false, err
	} else if dash == nil {
		return nil, false, fmt.Errorf("unable to retrieve dashboard after save")
	}

	// stash the raw value in context (if requested)
	finalMeta, err := utils.MetaAccessor(dash)
	if err != nil {
		return nil, false, err
	}
	access := GetLegacyAccess(ctx)
	if access != nil {
		access.DashboardID = finalMeta.GetDeprecatedInternalID() // nolint:staticcheck
	}
	return dash, created, err
}

func (a *dashboardSqlAccess) GetLibraryPanels(ctx context.Context, query LibraryPanelQuery) (*dashboardV0.LibraryPanelList, error) {
	limit := int(query.Limit)
	query.Limit += 1 // for continue
	if query.OrgID == 0 {
		return nil, fmt.Errorf("expected non zero orgID")
	}

	sqlx, err := a.sql(ctx)
	if err != nil {
		return nil, err
	}

	req := newLibraryQueryReq(sqlx, &query)
	rawQuery, err := sqltemplate.Execute(sqlQueryPanels, req)
	if err != nil {
		return nil, fmt.Errorf("execute template %q: %w", sqlQueryPanels.Name(), err)
	}
	q := rawQuery

	res := &dashboardV0.LibraryPanelList{}
	rows, err := sqlx.DB.GetSqlxSession().Query(ctx, q, req.GetArgs()...)
	defer func() {
		if rows != nil {
			_ = rows.Close()
		}
	}()
	if err != nil {
		return nil, err
	}

	type panel struct {
		ID        int64
		UID       string
		FolderUID sql.NullString

		Created   time.Time
		CreatedBy string

		Updated   time.Time
		UpdatedBy string

		Name        string
		Type        string
		Description string
		Model       []byte
	}

	var lastID int64
	for rows.Next() {
		p := panel{}
		err = rows.Scan(&p.ID, &p.UID, &p.FolderUID,
			&p.Created, &p.CreatedBy,
			&p.Updated, &p.UpdatedBy,
			&p.Name, &p.Type, &p.Description, &p.Model,
		)
		if err != nil {
			return res, err
		}
		lastID = p.ID

		item := dashboardV0.LibraryPanel{
			TypeMeta: metav1.TypeMeta{
				APIVersion: dashboardV0.APIVERSION,
				Kind:       "LibraryPanel",
			},
			ObjectMeta: metav1.ObjectMeta{
				Name:              p.UID,
				CreationTimestamp: metav1.NewTime(p.Created),
				ResourceVersion:   strconv.FormatInt(p.Updated.UnixMilli(), 10),
			},
			Spec: dashboardV0.LibraryPanelSpec{},
		}

		status := &dashboardV0.LibraryPanelStatus{
			Missing: v0alpha1.Unstructured{},
		}
		err = json.Unmarshal(p.Model, &item.Spec)
		if err != nil {
			return nil, err
		}
		err = json.Unmarshal(p.Model, &status.Missing.Object)
		if err != nil {
			return nil, err
		}

		if item.Spec.Title != p.Name {
			status.Warnings = append(status.Warnings, fmt.Sprintf("title mismatch (expected: %s)", p.Name))
		}
		if item.Spec.Description != p.Description {
			status.Warnings = append(status.Warnings, fmt.Sprintf("description mismatch (expected: %s)", p.Description))
		}
		if item.Spec.Type != p.Type {
			status.Warnings = append(status.Warnings, fmt.Sprintf("type mismatch (expected: %s)", p.Type))
		}
		item.Status = status

		// Remove the properties we are already showing
		for _, k := range []string{"type", "pluginVersion", "title", "description", "options", "fieldConfig", "datasource", "targets", "libraryPanel"} {
			delete(status.Missing.Object, k)
		}

		meta, err := utils.MetaAccessor(&item)
		if err != nil {
			return nil, err
		}
		if p.FolderUID.Valid {
			meta.SetFolder(p.FolderUID.String)
		}
		meta.SetCreatedBy(p.CreatedBy)
		meta.SetGeneration(1)
		meta.SetDeprecatedInternalID(p.ID) //nolint:staticcheck

		// Only set updated metadata if it is different
		if p.UpdatedBy != p.CreatedBy || p.Updated.Sub(p.Created) > time.Second {
			meta.SetUpdatedBy(p.UpdatedBy)
			meta.SetUpdatedTimestamp(&p.Updated)
			meta.SetGeneration(2)
		}

		res.Items = append(res.Items, item)
		if len(res.Items) > limit {
			res.Continue = strconv.FormatInt(lastID, 10)
			break
		}
	}
	if query.UID == "" {
		rv, err := sqlx.GetResourceVersion(ctx, "library_element", "updated")
		if err == nil {
			res.ResourceVersion = strconv.FormatInt(rv, 10)
		}
	}
	return res, err
}