package service

import (
	"context"
	"encoding/json"
	"fmt"
	"net"
	"strconv"
	"strings"
	"time"

	hostctx "github.com/fleetdm/fleet/server/contexts/host"
	"github.com/fleetdm/fleet/server/kolide"
	"github.com/fleetdm/fleet/server/pubsub"
	"github.com/go-kit/kit/log"
	"github.com/pkg/errors"
	"github.com/spf13/cast"
)

type osqueryError struct {
	message     string
	nodeInvalid bool
}

func (e osqueryError) Error() string {
	return e.message
}

func (e osqueryError) NodeInvalid() bool {
	return e.nodeInvalid
}

// Sometimes osquery gives us empty string where we expect an integer.
// We change the to "0" so it can be handled by the appropriate string to
// integer conversion function, as these will err on ""
func emptyToZero(val string) string {
	if val == "" {
		return "0"
	}
	return val
}

func (svc service) AuthenticateHost(ctx context.Context, nodeKey string) (*kolide.Host, error) {
	if nodeKey == "" {
		return nil, osqueryError{
			message:     "authentication error: missing node key",
			nodeInvalid: true,
		}
	}

	host, err := svc.ds.AuthenticateHost(nodeKey)
	if err != nil {
		switch err.(type) {
		case kolide.NotFoundError:
			return nil, osqueryError{
				message:     "authentication error: invalid node key: " + nodeKey,
				nodeInvalid: true,
			}
		default:
			return nil, osqueryError{
				message: "authentication error: " + err.Error(),
			}
		}
	}

	// Update the "seen" time used to calculate online status
	err = svc.ds.MarkHostSeen(host, svc.clock.Now())
	if err != nil {
		return nil, osqueryError{message: "failed to mark host seen: " + err.Error()}
	}

	return host, nil
}

func (svc service) EnrollAgent(ctx context.Context, enrollSecret, hostIdentifier string, hostDetails map[string](map[string]string)) (string, error) {
	secretName, err := svc.ds.VerifyEnrollSecret(enrollSecret)
	if err != nil {
		return "", osqueryError{
			message:     "enroll failed: " + err.Error(),
			nodeInvalid: true,
		}
	}

	nodeKey, err := kolide.RandomText(svc.config.Osquery.NodeKeySize)
	if err != nil {
		return "", osqueryError{
			message:     "generate node key failed: " + err.Error(),
			nodeInvalid: true,
		}
	}

	host, err := svc.ds.EnrollHost(hostIdentifier, nodeKey, secretName)
	if err != nil {
		return "", osqueryError{message: "save enroll failed: " + err.Error(), nodeInvalid: true}
	}

	// Save enrollment details if provided
	save := false
	if r, ok := hostDetails["os_version"]; ok {
		detailQueries["os_version"].IngestFunc(svc.logger, host, []map[string]string{r})
		save = true
	}
	if r, ok := hostDetails["osquery_info"]; ok {
		detailQueries["osquery_info"].IngestFunc(svc.logger, host, []map[string]string{r})
		save = true
	}
	if r, ok := hostDetails["system_info"]; ok {
		detailQueries["system_info"].IngestFunc(svc.logger, host, []map[string]string{r})
		save = true
	}
	if save {
		if err := svc.ds.SaveHost(host); err != nil {
			return "", osqueryError{message: "saving host details: " + err.Error(), nodeInvalid: true}
		}
	}

	return host.NodeKey, nil
}

func (svc service) GetClientConfig(ctx context.Context) (map[string]interface{}, error) {
	host, ok := hostctx.FromContext(ctx)
	if !ok {
		return nil, osqueryError{message: "internal error: missing host from request context"}
	}

	baseConfig, err := svc.ds.OptionsForPlatform(host.Platform)
	if err != nil {
		return nil, osqueryError{message: "internal error: fetching base config: " + err.Error()}
	}

	var config map[string]interface{}
	err = json.Unmarshal(baseConfig, &config)
	if err != nil {
		return nil, osqueryError{message: "internal error: parsing base configuration: " + err.Error()}
	}

	packs, err := svc.ds.ListPacksForHost(host.ID)
	if err != nil {
		return nil, osqueryError{message: "database error: " + err.Error()}
	}

	packConfig := kolide.Packs{}
	for _, pack := range packs {
		// first, we must figure out what queries are in this pack
		queries, err := svc.ds.ListScheduledQueriesInPack(pack.ID, kolide.ListOptions{})
		if err != nil {
			return nil, osqueryError{message: "database error: " + err.Error()}
		}

		// the serializable osquery config struct expects content in a
		// particular format, so we do the conversion here
		configQueries := kolide.Queries{}
		for _, query := range queries {
			queryContent := kolide.QueryContent{
				Query:    query.Query,
				Interval: query.Interval,
				Platform: query.Platform,
				Version:  query.Version,
				Removed:  query.Removed,
				Shard:    query.Shard,
				Denylist: query.Denylist,
			}

			if query.Removed != nil {
				queryContent.Removed = query.Removed
			}

			if query.Snapshot != nil && *query.Snapshot {
				queryContent.Snapshot = query.Snapshot
			}

			configQueries[query.Name] = queryContent
		}

		// finally, we add the pack to the client config struct with all of
		// the pack's queries
		packConfig[pack.Name] = kolide.PackContent{
			Platform: pack.Platform,
			Queries:  configQueries,
		}
	}

	if len(packConfig) > 0 {
		packJSON, err := json.Marshal(packConfig)
		if err != nil {
			return nil, osqueryError{message: "internal error: marshal pack JSON: " + err.Error()}
		}
		config["packs"] = json.RawMessage(packJSON)
	}

	// Save interval values if they have been updated. Note
	// config_tls_refresh can only be set in the osquery flags so is
	// ignored here.
	saveHost := false

	if options, ok := config["options"].(map[string]interface{}); ok {
		distributedIntervalVal, ok := options["distributed_interval"]
		distributedInterval, err := cast.ToUintE(distributedIntervalVal)
		if ok && err == nil && host.DistributedInterval != distributedInterval {
			host.DistributedInterval = distributedInterval
			saveHost = true
		}

		loggerTLSPeriodVal, ok := options["logger_tls_period"]
		loggerTLSPeriod, err := cast.ToUintE(loggerTLSPeriodVal)
		if ok && err == nil && host.LoggerTLSPeriod != loggerTLSPeriod {
			host.LoggerTLSPeriod = loggerTLSPeriod
			saveHost = true
		}
	}

	if saveHost {
		err := svc.ds.SaveHost(&host)
		if err != nil {
			return nil, err
		}
	}

	return config, nil
}

func (svc service) SubmitStatusLogs(ctx context.Context, logs []json.RawMessage) error {
	if err := svc.osqueryLogWriter.Status.Write(ctx, logs); err != nil {
		return osqueryError{message: "error writing status logs: " + err.Error()}
	}
	return nil
}

func (svc service) SubmitResultLogs(ctx context.Context, logs []json.RawMessage) error {
	if err := svc.osqueryLogWriter.Result.Write(ctx, logs); err != nil {
		return osqueryError{message: "error writing result logs: " + err.Error()}
	}
	return nil
}

// hostLabelQueryPrefix is appended before the query name when a query is
// provided as a label query. This allows the results to be retrieved when
// osqueryd writes the distributed query results.
const hostLabelQueryPrefix = "fleet_label_query_"

// hostDetailQueryPrefix is appended before the query name when a query is
// provided as a detail query.
const hostDetailQueryPrefix = "fleet_detail_query_"

// hostAdditionalQueryPrefix is appended before the query name when a query is
// provided as an additional query (additional info for hosts to retrieve).
const hostAdditionalQueryPrefix = "fleet_additional_query_"

// hostDistributedQueryPrefix is appended before the query name when a query is
// run from a distributed query campaign
const hostDistributedQueryPrefix = "fleet_distributed_query_"

// detailQueries defines the detail queries that should be run on the host, as
// well as how the results of those queries should be ingested into the
// kolide.Host data model. This map should not be modified at runtime.
var detailQueries = map[string]struct {
	Query      string
	IngestFunc func(logger log.Logger, host *kolide.Host, rows []map[string]string) error
}{
	"network_interface": {
		Query: `select address, mac
                        from interface_details id join interface_addresses ia
                               on ia.interface = id.interface where length(mac) > 0
                               order by (ibytes + obytes) desc`,
		IngestFunc: func(logger log.Logger, host *kolide.Host, rows []map[string]string) (err error) {
			if len(rows) == 0 {
				logger.Log("component", "service", "method", "IngestFunc", "err",
					"detail_query_network_interface expected 1 or more results")
				return nil
			}

			for _, row := range rows {
				ip := net.ParseIP(row["address"])
				if ip == nil {
					continue
				}

				// Skip link-local and loopback interfaces
				if ip.IsLinkLocalUnicast() || ip.IsLoopback() {
					continue
				}

				// Rows are ordered by traffic, so we will get the most active
				// interface by iterating in order
				host.PrimaryIP = row["address"]
				host.PrimaryMac = row["mac"]
				return nil
			}

			// If only link-local and loopback found, still use the first
			// interface.
			host.PrimaryIP = rows[0]["address"]
			host.PrimaryMac = rows[0]["mac"]
			return nil
		},
	},
	"os_version": {
		Query: "select * from os_version limit 1",
		IngestFunc: func(logger log.Logger, host *kolide.Host, rows []map[string]string) error {
			if len(rows) != 1 {
				logger.Log("component", "service", "method", "IngestFunc", "err",
					fmt.Sprintf("detail_query_os_version expected single result got %d", len(rows)))
				return nil
			}

			host.OSVersion = fmt.Sprintf(
				"%s %s.%s.%s",
				rows[0]["name"],
				rows[0]["major"],
				rows[0]["minor"],
				rows[0]["patch"],
			)
			host.OSVersion = strings.Trim(host.OSVersion, ".")

			if build, ok := rows[0]["build"]; ok {
				host.Build = build
			}

			host.Platform = rows[0]["platform"]
			host.PlatformLike = rows[0]["platform_like"]
			host.CodeName = rows[0]["code_name"]

			// On centos6 there is an osquery bug that leaves
			// platform empty. Here we workaround.
			if host.Platform == "" &&
				strings.Contains(strings.ToLower(rows[0]["name"]), "centos") {
				host.Platform = "centos"
			}

			return nil
		},
	},
	"osquery_flags": {
		// Collect the interval info (used for online status
		// calculation) from the osquery flags. We typically control
		// distributed_interval (but it's not required), and typically
		// do not control config_tls_refresh.
		Query: `select name, value from osquery_flags where name in ("distributed_interval", "config_tls_refresh", "config_refresh", "logger_tls_period")`,
		IngestFunc: func(logger log.Logger, host *kolide.Host, rows []map[string]string) error {
			var configTLSRefresh, configRefresh uint
			for _, row := range rows {
				switch row["name"] {

				case "distributed_interval":
					interval, err := strconv.Atoi(emptyToZero(row["value"]))
					if err != nil {
						return errors.Wrap(err, "parsing distributed_interval")
					}
					host.DistributedInterval = uint(interval)

				case "config_tls_refresh":
					// Prior to osquery 2.4.6, the flag was
					// called `config_tls_refresh`.
					interval, err := strconv.Atoi(emptyToZero(row["value"]))
					if err != nil {
						return errors.Wrap(err, "parsing config_tls_refresh")
					}
					configTLSRefresh = uint(interval)

				case "config_refresh":
					// After 2.4.6 `config_tls_refresh` was
					// aliased to `config_refresh`.
					interval, err := strconv.Atoi(emptyToZero(row["value"]))
					if err != nil {
						return errors.Wrap(err, "parsing config_refresh")
					}
					configRefresh = uint(interval)

				case "logger_tls_period":
					interval, err := strconv.Atoi(emptyToZero(row["value"]))
					if err != nil {
						return errors.Wrap(err, "parsing logger_tls_period")
					}
					host.LoggerTLSPeriod = uint(interval)
				}
			}

			// Since the `config_refresh` flag existed prior to
			// 2.4.6 and had a different meaning, we prefer
			// `config_tls_refresh` if it was set, and use
			// `config_refresh` as a fallback.
			if configTLSRefresh != 0 {
				host.ConfigTLSRefresh = configTLSRefresh
			} else {
				host.ConfigTLSRefresh = configRefresh
			}

			return nil
		},
	},
	"osquery_info": {
		Query: "select * from osquery_info limit 1",
		IngestFunc: func(logger log.Logger, host *kolide.Host, rows []map[string]string) error {
			if len(rows) != 1 {
				logger.Log("component", "service", "method", "IngestFunc", "err",
					fmt.Sprintf("detail_query_osquery_info expected single result got %d", len(rows)))
				return nil
			}

			host.OsqueryVersion = rows[0]["version"]

			return nil
		},
	},
	"system_info": {
		Query: "select * from system_info limit 1",
		IngestFunc: func(logger log.Logger, host *kolide.Host, rows []map[string]string) error {
			if len(rows) != 1 {
				logger.Log("component", "service", "method", "IngestFunc", "err",
					fmt.Sprintf("detail_query_system_info expected single result got %d", len(rows)))
				return nil
			}

			var err error
			host.PhysicalMemory, err = strconv.ParseInt(emptyToZero(rows[0]["physical_memory"]), 10, 64)
			if err != nil {
				return err
			}
			host.HostName = rows[0]["hostname"]
			host.UUID = rows[0]["uuid"]
			host.CPUType = rows[0]["cpu_type"]
			host.CPUSubtype = rows[0]["cpu_subtype"]
			host.CPUBrand = rows[0]["cpu_brand"]
			host.CPUPhysicalCores, err = strconv.Atoi(emptyToZero(rows[0]["cpu_physical_cores"]))
			if err != nil {
				return err
			}
			host.CPULogicalCores, err = strconv.Atoi(emptyToZero(rows[0]["cpu_logical_cores"]))
			if err != nil {
				return err
			}
			host.HardwareVendor = rows[0]["hardware_vendor"]
			host.HardwareModel = rows[0]["hardware_model"]
			host.HardwareVersion = rows[0]["hardware_version"]
			host.HardwareSerial = rows[0]["hardware_serial"]
			host.ComputerName = rows[0]["computer_name"]
			return nil
		},
	},
	"uptime": {
		Query: "select * from uptime limit 1",
		IngestFunc: func(logger log.Logger, host *kolide.Host, rows []map[string]string) error {
			if len(rows) != 1 {
				logger.Log("component", "service", "method", "IngestFunc", "err",
					fmt.Sprintf("detail_query_uptime expected single result got %d", len(rows)))
				return nil
			}

			uptimeSeconds, err := strconv.Atoi(emptyToZero(rows[0]["total_seconds"]))
			if err != nil {
				return err
			}
			host.Uptime = time.Duration(uptimeSeconds) * time.Second

			return nil
		},
	},
}

// hostDetailQueries returns the map of queries that should be executed by
// osqueryd to fill in the host details
func (svc service) hostDetailQueries(host kolide.Host) (map[string]string, error) {
	queries := make(map[string]string)
	if host.DetailUpdateTime.After(svc.clock.Now().Add(-svc.config.Osquery.DetailUpdateInterval)) {
		// No need to update already fresh details
		return queries, nil
	}

	for name, query := range detailQueries {
		queries[hostDetailQueryPrefix+name] = query.Query
	}

	// Get additional queries
	config, err := svc.ds.AppConfig()
	if err != nil {
		return nil, osqueryError{message: "get additional queries: " + err.Error()}
	}
	if config.AdditionalQueries == nil {
		// No additional queries set
		return queries, nil
	}

	var additionalQueries map[string]string
	if err := json.Unmarshal(*config.AdditionalQueries, &additionalQueries); err != nil {
		return nil, osqueryError{message: "unmarshal additional queries: " + err.Error()}
	}

	for name, query := range additionalQueries {
		queries[hostAdditionalQueryPrefix+name] = query
	}

	return queries, nil
}

func (svc service) GetDistributedQueries(ctx context.Context) (map[string]string, uint, error) {
	host, ok := hostctx.FromContext(ctx)
	if !ok {
		return nil, 0, osqueryError{message: "internal error: missing host from request context"}
	}

	queries, err := svc.hostDetailQueries(host)
	if err != nil {
		return nil, 0, err
	}

	// Retrieve the label queries that should be updated
	cutoff := svc.clock.Now().Add(-svc.config.Osquery.LabelUpdateInterval)
	labelQueries, err := svc.ds.LabelQueriesForHost(&host, cutoff)
	if err != nil {
		return nil, 0, osqueryError{message: "retrieving label queries: " + err.Error()}
	}

	for name, query := range labelQueries {
		queries[hostLabelQueryPrefix+name] = query
	}

	liveQueries, err := svc.liveQueryStore.QueriesForHost(host.ID)
	if err != nil {
		return nil, 0, osqueryError{message: "retrieve live queries: " + err.Error()}
	}

	for name, query := range liveQueries {
		queries[hostDistributedQueryPrefix+name] = query
	}

	accelerate := uint(0)
	if host.HostName == "" && host.Platform == "" {
		// Assume this host is just enrolling, and accelerate checkins
		// (to allow for platform restricted labels to run quickly
		// after platform is retrieved from details)
		accelerate = 10
	}

	return queries, accelerate, nil
}

// ingestDetailQuery takes the results of a detail query and modifies the
// provided kolide.Host appropriately.
func (svc service) ingestDetailQuery(host *kolide.Host, name string, rows []map[string]string) error {
	trimmedQuery := strings.TrimPrefix(name, hostDetailQueryPrefix)
	query, ok := detailQueries[trimmedQuery]
	if !ok {
		return osqueryError{message: "unknown detail query " + trimmedQuery}
	}

	err := query.IngestFunc(svc.logger, host, rows)
	if err != nil {
		return osqueryError{
			message: fmt.Sprintf("ingesting query %s: %s", name, err.Error()),
		}
	}

	return nil
}

// ingestLabelQuery records the results of label queries run by a host
func (svc service) ingestLabelQuery(host kolide.Host, query string, rows []map[string]string, results map[uint]bool) error {
	trimmedQuery := strings.TrimPrefix(query, hostLabelQueryPrefix)
	trimmedQueryNum, err := strconv.Atoi(emptyToZero(trimmedQuery))
	if err != nil {
		return errors.Wrap(err, "converting query from string to int")
	}
	// A label query matches if there is at least one result for that
	// query. We must also store negative results.
	results[uint(trimmedQueryNum)] = len(rows) > 0
	return nil
}

// ingestDistributedQuery takes the results of a distributed query and modifies the
// provided kolide.Host appropriately.
func (svc service) ingestDistributedQuery(host kolide.Host, name string, rows []map[string]string, failed bool, errMsg string) error {
	trimmedQuery := strings.TrimPrefix(name, hostDistributedQueryPrefix)

	campaignID, err := strconv.Atoi(emptyToZero(trimmedQuery))
	if err != nil {
		return osqueryError{message: "unable to parse campaign ID: " + trimmedQuery}
	}

	// Write the results to the pubsub store
	res := kolide.DistributedQueryResult{
		DistributedQueryCampaignID: uint(campaignID),
		Host:                       host,
		Rows:                       rows,
	}
	if failed {
		res.Error = &errMsg
	}

	err = svc.resultStore.WriteResult(res)
	if err != nil {
		nErr, ok := err.(pubsub.Error)
		if !ok || !nErr.NoSubscriber() {
			return osqueryError{message: "writing results: " + err.Error()}
		}

		// If there are no subscribers, the campaign is "orphaned"
		// and should be closed so that we don't continue trying to
		// execute that query when we can't write to any subscriber
		campaign, err := svc.ds.DistributedQueryCampaign(uint(campaignID))
		if err != nil {
			return osqueryError{message: "loading orphaned campaign: " + err.Error()}
		}

		if campaign.CreatedAt.After(svc.clock.Now().Add(-5 * time.Second)) {
			// Give the client 5 seconds to connect before considering the
			// campaign orphaned
			return osqueryError{message: "campaign waiting for listener (please retry)"}
		}

		if campaign.Status != kolide.QueryComplete {
			campaign.Status = kolide.QueryComplete
			if err := svc.ds.SaveDistributedQueryCampaign(campaign); err != nil {
				return osqueryError{message: "closing orphaned campaign: " + err.Error()}
			}
		}

		if err := svc.liveQueryStore.StopQuery(strconv.Itoa(int(campaignID))); err != nil {
			return osqueryError{message: "stopping orphaned campaign: " + err.Error()}
		}

		// No need to record query completion in this case
		return nil
	}

	err = svc.liveQueryStore.QueryCompletedByHost(strconv.Itoa(int(campaignID)), host.ID)
	if err != nil {
		return osqueryError{message: "record query completion: " + err.Error()}
	}

	return nil
}

func (svc service) SubmitDistributedQueryResults(ctx context.Context, results kolide.OsqueryDistributedQueryResults, statuses map[string]kolide.OsqueryStatus, messages map[string]string) error {
	host, ok := hostctx.FromContext(ctx)

	if !ok {
		return osqueryError{message: "internal error: missing host from request context"}
	}

	var err error
	detailUpdated := false // Whether detail or additional was updated
	additionalResults := make(kolide.OsqueryDistributedQueryResults)
	labelResults := map[uint]bool{}
	for query, rows := range results {
		switch {
		case strings.HasPrefix(query, hostDetailQueryPrefix):
			err = svc.ingestDetailQuery(&host, query, rows)
			detailUpdated = true
		case strings.HasPrefix(query, hostAdditionalQueryPrefix):
			name := strings.TrimPrefix(query, hostAdditionalQueryPrefix)
			additionalResults[name] = rows
			detailUpdated = true
		case strings.HasPrefix(query, hostLabelQueryPrefix):
			err = svc.ingestLabelQuery(host, query, rows, labelResults)
		case strings.HasPrefix(query, hostDistributedQueryPrefix):
			// osquery docs say any nonzero (string) value for
			// status indicates a query error
			status, ok := statuses[query]
			failed := (ok && status != kolide.StatusOK)
			err = svc.ingestDistributedQuery(host, query, rows, failed, messages[query])
		default:
			err = osqueryError{message: "unknown query prefix: " + query}
		}

		if err != nil {
			return osqueryError{message: "failed to ingest result: " + err.Error()}
		}

	}

	if len(labelResults) > 0 {
		host.LabelUpdateTime = svc.clock.Now()
		err = svc.ds.RecordLabelQueryExecutions(&host, labelResults, svc.clock.Now())
		if err != nil {
			return osqueryError{message: "failed to save labels: " + err.Error()}
		}
	}

	if detailUpdated {
		host.DetailUpdateTime = svc.clock.Now()
		additionalJSON, err := json.Marshal(additionalResults)
		if err != nil {
			return osqueryError{message: "failed to marshal additional: " + err.Error()}
		}
		additional := json.RawMessage(additionalJSON)
		host.Additional = &additional
	}

	if len(labelResults) > 0 || detailUpdated {
		err = svc.ds.SaveHost(&host)
		if err != nil {
			return osqueryError{message: "failed to update host details: " + err.Error()}
		}
	}

	return nil
}