package service

import (
	"context"
	"time"

	"github.com/grafana/grafana-plugin-sdk-go/backend"
	"github.com/grafana/grafana/pkg/api/dtos"
	"github.com/grafana/grafana/pkg/infra/log"
	"github.com/grafana/grafana/pkg/models"
	"github.com/grafana/grafana/pkg/services/accesscontrol"
	"github.com/grafana/grafana/pkg/services/annotations"
	"github.com/grafana/grafana/pkg/services/dashboards"
	"github.com/grafana/grafana/pkg/services/datasources"
	"github.com/grafana/grafana/pkg/services/publicdashboards"
	. "github.com/grafana/grafana/pkg/services/publicdashboards/models"
	"github.com/grafana/grafana/pkg/services/publicdashboards/queries"
	"github.com/grafana/grafana/pkg/services/publicdashboards/validation"
	"github.com/grafana/grafana/pkg/services/query"
	"github.com/grafana/grafana/pkg/services/user"
	"github.com/grafana/grafana/pkg/setting"
	"github.com/grafana/grafana/pkg/tsdb/grafanads"
	"github.com/grafana/grafana/pkg/tsdb/intervalv2"
	"github.com/grafana/grafana/pkg/tsdb/legacydata"
)

// Define the Service Implementation. We're generating mock implementation
// automatically
type PublicDashboardServiceImpl struct {
	log                log.Logger
	cfg                *setting.Cfg
	store              publicdashboards.Store
	intervalCalculator intervalv2.Calculator
	QueryDataService   *query.Service
	AnnotationsRepo    annotations.Repository
}

var LogPrefix = "publicdashboards.service"

// Gives us compile time error if the service does not adhere to the contract of
// the interface
var _ publicdashboards.Service = (*PublicDashboardServiceImpl)(nil)

// Factory for method used by wire to inject dependencies.
// builds the service, and api, and configures routes
func ProvideService(
	cfg *setting.Cfg,
	store publicdashboards.Store,
	qds *query.Service,
	anno annotations.Repository,
) *PublicDashboardServiceImpl {
	return &PublicDashboardServiceImpl{
		log:                log.New(LogPrefix),
		cfg:                cfg,
		store:              store,
		intervalCalculator: intervalv2.NewCalculator(),
		QueryDataService:   qds,
		AnnotationsRepo:    anno,
	}
}

// Gets a list of public dashboards by orgId
func (pd *PublicDashboardServiceImpl) ListPublicDashboards(ctx context.Context, orgId int64) ([]PublicDashboardListResponse, error) {
	return pd.store.ListPublicDashboards(ctx, orgId)
}

// Gets a dashboard by Uid
func (pd *PublicDashboardServiceImpl) GetDashboard(ctx context.Context, dashboardUid string) (*models.Dashboard, error) {
	dashboard, err := pd.store.GetDashboard(ctx, dashboardUid)

	if err != nil {
		return nil, err
	}

	return dashboard, err
}

// Gets public dashboard via access token
func (pd *PublicDashboardServiceImpl) GetPublicDashboard(ctx context.Context, accessToken string) (*PublicDashboard, *models.Dashboard, error) {
	pubdash, dash, err := pd.store.GetPublicDashboard(ctx, accessToken)
	ctxLogger := pd.log.FromContext(ctx)

	if err != nil {
		return nil, nil, err
	}

	if pubdash == nil {
		ctxLogger.Error("GetPublicDashboard: Public dashboard not found", "accessToken", accessToken)
		return nil, nil, ErrPublicDashboardNotFound
	}

	if dash == nil {
		ctxLogger.Error("GetPublicDashboard: Dashboard not found", "accessToken", accessToken)
		return nil, nil, ErrPublicDashboardNotFound
	}

	if !pubdash.IsEnabled {
		ctxLogger.Error("GetPublicDashboard: Public dashboard is disabled", "accessToken", accessToken)
		return nil, nil, ErrPublicDashboardNotFound
	}

	return pubdash, dash, nil
}

// GetPublicDashboardConfig is a helper method to retrieve the public dashboard configuration for a given dashboard from the database
func (pd *PublicDashboardServiceImpl) GetPublicDashboardConfig(ctx context.Context, orgId int64, dashboardUid string) (*PublicDashboard, error) {
	pdc, err := pd.store.GetPublicDashboardConfig(ctx, orgId, dashboardUid)
	if err != nil {
		return nil, err
	}

	return pdc, nil
}

// SavePublicDashboardConfig is a helper method to persist the sharing config
// to the database. It handles validations for sharing config and persistence
func (pd *PublicDashboardServiceImpl) SavePublicDashboardConfig(ctx context.Context, u *user.SignedInUser, dto *SavePublicDashboardConfigDTO) (*PublicDashboard, error) {
	// validate if the dashboard exists
	dashboard, err := pd.GetDashboard(ctx, dto.DashboardUid)
	if err != nil {
		return nil, err
	}

	// set default value for time settings
	if dto.PublicDashboard.TimeSettings == nil {
		dto.PublicDashboard.TimeSettings = &TimeSettings{}
	}

	// get existing public dashboard if exists
	existingPubdash, err := pd.store.GetPublicDashboardByUid(ctx, dto.PublicDashboard.Uid)
	if err != nil {
		return nil, err
	}

	// save changes
	var pubdashUid string
	if existingPubdash == nil {
		err = validation.ValidateSavePublicDashboard(dto, dashboard)
		if err != nil {
			return nil, err
		}
		pubdashUid, err = pd.savePublicDashboardConfig(ctx, dto)
	} else {
		pubdashUid, err = pd.updatePublicDashboardConfig(ctx, dto)
	}
	if err != nil {
		return nil, err
	}

	//Get latest public dashboard to return
	newPubdash, err := pd.store.GetPublicDashboardByUid(ctx, pubdashUid)
	if err != nil {
		return nil, err
	}

	pd.logIsEnabledChanged(existingPubdash, newPubdash, u)

	return newPubdash, err
}

// Called by SavePublicDashboardConfig this handles business logic
// to generate token and calls create at the database layer
func (pd *PublicDashboardServiceImpl) savePublicDashboardConfig(ctx context.Context, dto *SavePublicDashboardConfigDTO) (string, error) {
	uid, err := pd.store.GenerateNewPublicDashboardUid(ctx)
	if err != nil {
		return "", err
	}

	accessToken, err := pd.store.GenerateNewPublicDashboardAccessToken(ctx)
	if err != nil {
		return "", err
	}

	cmd := SavePublicDashboardConfigCommand{
		PublicDashboard: PublicDashboard{
			Uid:          uid,
			DashboardUid: dto.DashboardUid,
			OrgId:        dto.OrgId,
			IsEnabled:    dto.PublicDashboard.IsEnabled,
			TimeSettings: dto.PublicDashboard.TimeSettings,
			CreatedBy:    dto.UserId,
			CreatedAt:    time.Now(),
			AccessToken:  accessToken,
		},
	}

	err = pd.store.SavePublicDashboardConfig(ctx, cmd)
	if err != nil {
		return "", err
	}

	return uid, nil
}

// Called by SavePublicDashboard this handles business logic for updating a
// dashboard and calls update at the database layer
func (pd *PublicDashboardServiceImpl) updatePublicDashboardConfig(ctx context.Context, dto *SavePublicDashboardConfigDTO) (string, error) {
	cmd := SavePublicDashboardConfigCommand{
		PublicDashboard: PublicDashboard{
			Uid:          dto.PublicDashboard.Uid,
			IsEnabled:    dto.PublicDashboard.IsEnabled,
			TimeSettings: dto.PublicDashboard.TimeSettings,
			UpdatedBy:    dto.UserId,
			UpdatedAt:    time.Now(),
		},
	}

	return dto.PublicDashboard.Uid, pd.store.UpdatePublicDashboardConfig(ctx, cmd)
}

func (pd *PublicDashboardServiceImpl) GetQueryDataResponse(ctx context.Context, skipCache bool, queryDto PublicDashboardQueryDTO, panelId int64, accessToken string) (*backend.QueryDataResponse, error) {
	publicDashboard, dashboard, err := pd.GetPublicDashboard(ctx, accessToken)
	if err != nil {
		return nil, err
	}

	metricReq, err := pd.GetMetricRequest(ctx, dashboard, publicDashboard, panelId, queryDto)
	if err != nil {
		return nil, err
	}

	if len(metricReq.Queries) == 0 {
		return nil, nil
	}

	anonymousUser := pd.BuildAnonymousUser(ctx, dashboard)
	res, err := pd.QueryDataService.QueryData(ctx, anonymousUser, skipCache, metricReq)

	reqDatasources := metricReq.GetUniqueDatasourceTypes()
	if err != nil {
		LogQueryFailure(reqDatasources, pd.log, err)
		return nil, err
	}
	LogQuerySuccess(reqDatasources, pd.log)

	queries.SanitizeMetadataFromQueryData(res)

	return res, nil
}

func (pd *PublicDashboardServiceImpl) GetMetricRequest(ctx context.Context, dashboard *models.Dashboard, publicDashboard *PublicDashboard, panelId int64, queryDto PublicDashboardQueryDTO) (dtos.MetricRequest, error) {
	err := validation.ValidateQueryPublicDashboardRequest(queryDto)
	if err != nil {
		return dtos.MetricRequest{}, err
	}

	metricReqDTO, err := pd.buildMetricRequest(
		ctx,
		dashboard,
		publicDashboard,
		panelId,
		queryDto,
	)
	if err != nil {
		return dtos.MetricRequest{}, err
	}

	return metricReqDTO, nil
}

func (pd *PublicDashboardServiceImpl) GetAnnotations(ctx context.Context, reqDTO AnnotationsQueryDTO, accessToken string) ([]AnnotationEvent, error) {
	_, dash, err := pd.GetPublicDashboard(ctx, accessToken)
	if err != nil {
		return nil, err
	}

	annoDto, err := UnmarshalDashboardAnnotations(dash.Data)
	if err != nil {
		return nil, err
	}

	anonymousUser := pd.BuildAnonymousUser(ctx, dash)

	uniqueEvents := make(map[int64]AnnotationEvent, 0)
	for _, anno := range annoDto.Annotations.List {
		// skip annotations that are not enabled or are not a grafana datasource
		if !anno.Enable || (*anno.Datasource.Uid != grafanads.DatasourceUID && *anno.Datasource.Uid != grafanads.DatasourceName) {
			continue
		}
		annoQuery := &annotations.ItemQuery{
			From:         reqDTO.From,
			To:           reqDTO.To,
			OrgId:        dash.OrgId,
			DashboardId:  dash.Id,
			DashboardUid: dash.Uid,
			Limit:        anno.Target.Limit,
			MatchAny:     anno.Target.MatchAny,
			SignedInUser: anonymousUser,
		}

		if anno.Target.Type == "tags" {
			annoQuery.DashboardId = 0
			annoQuery.Tags = anno.Target.Tags
		}

		annotationItems, err := pd.AnnotationsRepo.Find(ctx, annoQuery)
		if err != nil {
			return nil, err
		}

		for _, item := range annotationItems {
			event := AnnotationEvent{
				Id:          item.Id,
				DashboardId: item.DashboardId,
				Tags:        item.Tags,
				IsRegion:    item.TimeEnd > 0 && item.Time != item.TimeEnd,
				Text:        item.Text,
				Color:       *anno.IconColor,
				Time:        item.Time,
				TimeEnd:     item.TimeEnd,
				Source:      anno,
			}

			// We want dashboard annotations to reference the panel they're for. If no panelId is provided, they'll show up on all panels
			// which is only intended for tag and org annotations.
			if anno.Type == "dashboard" {
				event.PanelId = item.PanelId
			}

			// We want events from tag queries to overwrite existing events
			_, has := uniqueEvents[event.Id]
			if !has || (has && anno.Target.Type == "tags") {
				uniqueEvents[event.Id] = event
			}
		}
	}

	var results []AnnotationEvent
	for _, result := range uniqueEvents {
		results = append(results, result)
	}

	return results, nil
}

// buildMetricRequest merges public dashboard parameters with
// dashboard and returns a metrics request to be sent to query backend
func (pd *PublicDashboardServiceImpl) buildMetricRequest(ctx context.Context, dashboard *models.Dashboard, publicDashboard *PublicDashboard, panelId int64, reqDTO PublicDashboardQueryDTO) (dtos.MetricRequest, error) {
	// group queries by panel
	queriesByPanel := queries.GroupQueriesByPanelId(dashboard.Data)
	queries, ok := queriesByPanel[panelId]
	if !ok {
		return dtos.MetricRequest{}, ErrPublicDashboardPanelNotFound
	}

	ts := publicDashboard.BuildTimeSettings(dashboard)

	// determine safe resolution to query data at
	safeInterval, safeResolution := pd.getSafeIntervalAndMaxDataPoints(reqDTO, ts)
	for i := range queries {
		queries[i].Set("intervalMs", safeInterval)
		queries[i].Set("maxDataPoints", safeResolution)
	}

	return dtos.MetricRequest{
		From:    ts.From,
		To:      ts.To,
		Queries: queries,
	}, nil
}

// BuildAnonymousUser creates a user with permissions to read from all datasources used in the dashboard
func (pd *PublicDashboardServiceImpl) BuildAnonymousUser(ctx context.Context, dashboard *models.Dashboard) *user.SignedInUser {
	datasourceUids := queries.GetUniqueDashboardDatasourceUids(dashboard.Data)

	// Create a user with blank permissions
	anonymousUser := &user.SignedInUser{OrgID: dashboard.OrgId, Permissions: make(map[int64]map[string][]string)}

	// Scopes needed for Annotation queries
	annotationScopes := []string{accesscontrol.ScopeAnnotationsTypeDashboard}
	// Need to access all dashboards since tags annotations span across all dashboards
	dashboardScopes := []string{dashboards.ScopeDashboardsProvider.GetResourceAllScope()}

	// Scopes needed for datasource queries
	queryScopes := make([]string, 0)
	readScopes := make([]string, 0)
	for _, uid := range datasourceUids {
		scope := datasources.ScopeProvider.GetResourceScopeUID(uid)
		queryScopes = append(queryScopes, scope)
		readScopes = append(readScopes, scope)
	}

	// Apply all scopes to the actions we need the user to be able to perform
	permissions := make(map[string][]string)
	permissions[datasources.ActionQuery] = queryScopes
	permissions[datasources.ActionRead] = readScopes
	permissions[accesscontrol.ActionAnnotationsRead] = annotationScopes
	permissions[dashboards.ActionDashboardsRead] = dashboardScopes

	anonymousUser.Permissions[dashboard.OrgId] = permissions

	return anonymousUser
}

func (pd *PublicDashboardServiceImpl) PublicDashboardEnabled(ctx context.Context, dashboardUid string) (bool, error) {
	return pd.store.PublicDashboardEnabled(ctx, dashboardUid)
}

func (pd *PublicDashboardServiceImpl) AccessTokenExists(ctx context.Context, accessToken string) (bool, error) {
	return pd.store.AccessTokenExists(ctx, accessToken)
}

func (pd *PublicDashboardServiceImpl) GetPublicDashboardOrgId(ctx context.Context, accessToken string) (int64, error) {
	return pd.store.GetPublicDashboardOrgId(ctx, accessToken)
}

// intervalMS and maxQueryData values are being calculated on the frontend for regular dashboards
// we are doing the same for public dashboards but because this access would be public, we need a way to keep this
// values inside reasonable bounds to avoid an attack that could hit data sources with a small interval and a big
// time range and perform big calculations
// this is an additional validation, all data sources implements QueryData interface and should have proper validations
// of these limits
// for the maxDataPoints we took a hard limit from prometheus which is 11000
func (pd *PublicDashboardServiceImpl) getSafeIntervalAndMaxDataPoints(reqDTO PublicDashboardQueryDTO, ts TimeSettings) (int64, int64) {
	// arbitrary max value for all data sources, it is actually a hard limit defined in prometheus
	safeResolution := int64(11000)

	// interval calculated on the frontend
	interval := time.Duration(reqDTO.IntervalMs) * time.Millisecond

	// calculate a safe interval with time range from dashboard and safeResolution
	dataTimeRange := legacydata.NewDataTimeRange(ts.From, ts.To)
	tr := backend.TimeRange{
		From: dataTimeRange.GetFromAsTimeUTC(),
		To:   dataTimeRange.GetToAsTimeUTC(),
	}
	safeInterval := pd.intervalCalculator.CalculateSafeInterval(tr, safeResolution)

	if interval > safeInterval.Value {
		return reqDTO.IntervalMs, reqDTO.MaxDataPoints
	}

	return safeInterval.Value.Milliseconds(), safeResolution
}

// Log when PublicDashboard.IsEnabled changed
func (pd *PublicDashboardServiceImpl) logIsEnabledChanged(existingPubdash *PublicDashboard, newPubdash *PublicDashboard, u *user.SignedInUser) {
	if publicDashboardIsEnabledChanged(existingPubdash, newPubdash) {
		verb := "disabled"
		if newPubdash.IsEnabled {
			verb = "enabled"
		}
		pd.log.Info("Public dashboard "+verb, "publicDashboardUid", newPubdash.Uid, "dashboardUid", newPubdash.DashboardUid, "user", u.Login)
	}
}

// Checks to see if PublicDashboard.Isenabled is true on create or changed on update
func publicDashboardIsEnabledChanged(existingPubdash *PublicDashboard, newPubdash *PublicDashboard) bool {
	// creating dashboard, enabled true
	newDashCreated := existingPubdash == nil && newPubdash.IsEnabled
	// updating dashboard, enabled changed
	isEnabledChanged := existingPubdash != nil && newPubdash.IsEnabled != existingPubdash.IsEnabled
	return newDashCreated || isEnabledChanged
}