package main

import (
	"context"
	"encoding/csv"
	"encoding/json"
	"fmt"
	"net/url"
	"os"
	"sort"
	"strconv"
	"strings"
	"text/template"
	"time"

	"github.com/fatih/color"
	"github.com/go-openapi/strfmt"
	log "github.com/sirupsen/logrus"
	"github.com/spf13/cobra"
	"gopkg.in/yaml.v2"

	"github.com/crowdsecurity/go-cs-lib/version"

	"github.com/crowdsecurity/crowdsec/cmd/crowdsec-cli/require"
	"github.com/crowdsecurity/crowdsec/pkg/apiclient"
	"github.com/crowdsecurity/crowdsec/pkg/database"
	"github.com/crowdsecurity/crowdsec/pkg/models"
	"github.com/crowdsecurity/crowdsec/pkg/types"
)

func DecisionsFromAlert(alert *models.Alert) string {
	ret := ""
	var decMap = make(map[string]int)
	for _, decision := range alert.Decisions {
		k := *decision.Type
		if *decision.Simulated {
			k = fmt.Sprintf("(simul)%s", k)
		}
		v := decMap[k]
		decMap[k] = v + 1
	}
	for k, v := range decMap {
		if len(ret) > 0 {
			ret += " "
		}
		ret += fmt.Sprintf("%s:%d", k, v)
	}
	return ret
}

func DateFromAlert(alert *models.Alert) string {
	ts, err := time.Parse(time.RFC3339, alert.CreatedAt)
	if err != nil {
		log.Infof("while parsing %s with %s : %s", alert.CreatedAt, time.RFC3339, err)
		return alert.CreatedAt
	}
	return ts.Format(time.RFC822)
}

func SourceFromAlert(alert *models.Alert) string {

	//more than one item, just number and scope
	if len(alert.Decisions) > 1 {
		return fmt.Sprintf("%d %ss (%s)", len(alert.Decisions), *alert.Decisions[0].Scope, *alert.Decisions[0].Origin)
	}

	//fallback on single decision information
	if len(alert.Decisions) == 1 {
		return fmt.Sprintf("%s:%s", *alert.Decisions[0].Scope, *alert.Decisions[0].Value)
	}

	//try to compose a human friendly version
	if *alert.Source.Value != "" && *alert.Source.Scope != "" {
		scope := fmt.Sprintf("%s:%s", *alert.Source.Scope, *alert.Source.Value)
		extra := ""
		if alert.Source.Cn != "" {
			extra = alert.Source.Cn
		}
		if alert.Source.AsNumber != "" {
			extra += fmt.Sprintf("/%s", alert.Source.AsNumber)
		}
		if alert.Source.AsName != "" {
			extra += fmt.Sprintf("/%s", alert.Source.AsName)
		}

		if extra != "" {
			scope += " (" + extra + ")"
		}
		return scope
	}
	return ""
}

func AlertsToTable(alerts *models.GetAlertsResponse, printMachine bool) error {

	if csConfig.Cscli.Output == "raw" {
		csvwriter := csv.NewWriter(os.Stdout)
		header := []string{"id", "scope", "value", "reason", "country", "as", "decisions", "created_at"}
		if printMachine {
			header = append(header, "machine")
		}
		err := csvwriter.Write(header)
		if err != nil {
			return err
		}
		for _, alertItem := range *alerts {
			row := []string{
				fmt.Sprintf("%d", alertItem.ID),
				*alertItem.Source.Scope,
				*alertItem.Source.Value,
				*alertItem.Scenario,
				alertItem.Source.Cn,
				alertItem.Source.GetAsNumberName(),
				DecisionsFromAlert(alertItem),
				*alertItem.StartAt,
			}
			if printMachine {
				row = append(row, alertItem.MachineID)
			}
			err := csvwriter.Write(row)
			if err != nil {
				return err
			}
		}
		csvwriter.Flush()
	} else if csConfig.Cscli.Output == "json" {
		if *alerts == nil {
			// avoid returning "null" in json
			// could be cleaner if we used slice of alerts directly
			fmt.Println("[]")
			return nil
		}
		x, _ := json.MarshalIndent(alerts, "", " ")
		fmt.Printf("%s", string(x))
	} else if csConfig.Cscli.Output == "human" {
		if len(*alerts) == 0 {
			fmt.Println("No active alerts")
			return nil
		}
		alertsTable(color.Output, alerts, printMachine)
	}
	return nil
}

var alertTemplate = `
################################################################################################

 - ID           : {{.ID}}
 - Date         : {{.CreatedAt}}
 - Machine      : {{.MachineID}}
 - Simulation   : {{.Simulated}}
 - Reason       : {{.Scenario}}
 - Events Count : {{.EventsCount}}
 - Scope:Value  : {{.Source.Scope}}{{if .Source.Value}}:{{.Source.Value}}{{end}}
 - Country      : {{.Source.Cn}}
 - AS           : {{.Source.AsName}}
 - Begin        : {{.StartAt}}
 - End          : {{.StopAt}}
 - UUID         : {{.UUID}}

`

func DisplayOneAlert(alert *models.Alert, withDetail bool) error {
	if csConfig.Cscli.Output == "human" {
		tmpl, err := template.New("alert").Parse(alertTemplate)
		if err != nil {
			return err
		}
		err = tmpl.Execute(os.Stdout, alert)
		if err != nil {
			return err
		}

		alertDecisionsTable(color.Output, alert)

		if len(alert.Meta) > 0 {
			fmt.Printf("\n - Context  :\n")
			sort.Slice(alert.Meta, func(i, j int) bool {
				return alert.Meta[i].Key < alert.Meta[j].Key
			})
			table := newTable(color.Output)
			table.SetRowLines(false)
			table.SetHeaders("Key", "Value")
			for _, meta := range alert.Meta {
				var valSlice []string
				if err := json.Unmarshal([]byte(meta.Value), &valSlice); err != nil {
					return fmt.Errorf("unknown context value type '%s' : %s", meta.Value, err)
				}
				for _, value := range valSlice {
					table.AddRow(
						meta.Key,
						value,
					)
				}
			}
			table.Render()
		}

		if withDetail {
			fmt.Printf("\n - Events  :\n")
			for _, event := range alert.Events {
				alertEventTable(color.Output, event)
			}
		}
	}
	return nil
}

type cliAlerts struct{}

func NewCLIAlerts() *cliAlerts {
	return &cliAlerts{}
}

func (cli cliAlerts) NewCommand() *cobra.Command {
	cmd := &cobra.Command{
		Use:               "alerts [action]",
		Short:             "Manage alerts",
		Args:              cobra.MinimumNArgs(1),
		DisableAutoGenTag: true,
		Aliases:           []string{"alert"},
		PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
			var err error
			if err := csConfig.LoadAPIClient(); err != nil {
				return fmt.Errorf("loading api client: %w", err)
			}
			apiURL, err := url.Parse(csConfig.API.Client.Credentials.URL)
			if err != nil {
				return fmt.Errorf("parsing api url %s: %w", apiURL, err)
			}
			Client, err = apiclient.NewClient(&apiclient.Config{
				MachineID:     csConfig.API.Client.Credentials.Login,
				Password:      strfmt.Password(csConfig.API.Client.Credentials.Password),
				UserAgent:     fmt.Sprintf("crowdsec/%s", version.String()),
				URL:           apiURL,
				VersionPrefix: "v1",
			})

			if err != nil {
				return fmt.Errorf("new api client: %w", err)
			}
			return nil
		},
	}

	cmd.AddCommand(cli.NewListCmd())
	cmd.AddCommand(cli.NewInspectCmd())
	cmd.AddCommand(cli.NewFlushCmd())
	cmd.AddCommand(cli.NewDeleteCmd())

	return cmd
}

func (cli cliAlerts) NewListCmd() *cobra.Command {
	var alertListFilter = apiclient.AlertsListOpts{
		ScopeEquals:    new(string),
		ValueEquals:    new(string),
		ScenarioEquals: new(string),
		IPEquals:       new(string),
		RangeEquals:    new(string),
		Since:          new(string),
		Until:          new(string),
		TypeEquals:     new(string),
		IncludeCAPI:    new(bool),
		OriginEquals:   new(string),
	}
	limit := new(int)
	contained := new(bool)
	var printMachine bool

	cmd := &cobra.Command{
		Use:   "list [filters]",
		Short: "List alerts",
		Example: `cscli alerts list
cscli alerts list --ip 1.2.3.4
cscli alerts list --range 1.2.3.0/24
cscli alerts list -s crowdsecurity/ssh-bf
cscli alerts list --type ban`,
		DisableAutoGenTag: true,
		RunE: func(cmd *cobra.Command, args []string) error {
			var err error

			if err := manageCliDecisionAlerts(alertListFilter.IPEquals, alertListFilter.RangeEquals,
				alertListFilter.ScopeEquals, alertListFilter.ValueEquals); err != nil {
				printHelp(cmd)
				return err
			}
			if limit != nil {
				alertListFilter.Limit = limit
			}

			if *alertListFilter.Until == "" {
				alertListFilter.Until = nil
			} else if strings.HasSuffix(*alertListFilter.Until, "d") {
				/*time.ParseDuration support hours 'h' as bigger unit, let's make the user's life easier*/
				realDuration := strings.TrimSuffix(*alertListFilter.Until, "d")
				days, err := strconv.Atoi(realDuration)
				if err != nil {
					printHelp(cmd)
					return fmt.Errorf("can't parse duration %s, valid durations format: 1d, 4h, 4h15m", *alertListFilter.Until)
				}
				*alertListFilter.Until = fmt.Sprintf("%d%s", days*24, "h")
			}
			if *alertListFilter.Since == "" {
				alertListFilter.Since = nil
			} else if strings.HasSuffix(*alertListFilter.Since, "d") {
				/*time.ParseDuration support hours 'h' as bigger unit, let's make the user's life easier*/
				realDuration := strings.TrimSuffix(*alertListFilter.Since, "d")
				days, err := strconv.Atoi(realDuration)
				if err != nil {
					printHelp(cmd)
					return fmt.Errorf("can't parse duration %s, valid durations format: 1d, 4h, 4h15m", *alertListFilter.Since)
				}
				*alertListFilter.Since = fmt.Sprintf("%d%s", days*24, "h")
			}

			if *alertListFilter.IncludeCAPI {
				*alertListFilter.Limit = 0
			}

			if *alertListFilter.TypeEquals == "" {
				alertListFilter.TypeEquals = nil
			}
			if *alertListFilter.ScopeEquals == "" {
				alertListFilter.ScopeEquals = nil
			}
			if *alertListFilter.ValueEquals == "" {
				alertListFilter.ValueEquals = nil
			}
			if *alertListFilter.ScenarioEquals == "" {
				alertListFilter.ScenarioEquals = nil
			}
			if *alertListFilter.IPEquals == "" {
				alertListFilter.IPEquals = nil
			}
			if *alertListFilter.RangeEquals == "" {
				alertListFilter.RangeEquals = nil
			}

			if *alertListFilter.OriginEquals == "" {
				alertListFilter.OriginEquals = nil
			}

			if contained != nil && *contained {
				alertListFilter.Contains = new(bool)
			}

			alerts, _, err := Client.Alerts.List(context.Background(), alertListFilter)
			if err != nil {
				return fmt.Errorf("unable to list alerts: %v", err)
			}

			err = AlertsToTable(alerts, printMachine)
			if err != nil {
				return fmt.Errorf("unable to list alerts: %v", err)
			}

			return nil
		},
	}
	cmd.Flags().SortFlags = false
	cmd.Flags().BoolVarP(alertListFilter.IncludeCAPI, "all", "a", false, "Include decisions from Central API")
	cmd.Flags().StringVar(alertListFilter.Until, "until", "", "restrict to alerts older than until (ie. 4h, 30d)")
	cmd.Flags().StringVar(alertListFilter.Since, "since", "", "restrict to alerts newer than since (ie. 4h, 30d)")
	cmd.Flags().StringVarP(alertListFilter.IPEquals, "ip", "i", "", "restrict to alerts from this source ip (shorthand for --scope ip --value <IP>)")
	cmd.Flags().StringVarP(alertListFilter.ScenarioEquals, "scenario", "s", "", "the scenario (ie. crowdsecurity/ssh-bf)")
	cmd.Flags().StringVarP(alertListFilter.RangeEquals, "range", "r", "", "restrict to alerts from this range (shorthand for --scope range --value <RANGE/X>)")
	cmd.Flags().StringVar(alertListFilter.TypeEquals, "type", "", "restrict to alerts with given decision type (ie. ban, captcha)")
	cmd.Flags().StringVar(alertListFilter.ScopeEquals, "scope", "", "restrict to alerts of this scope (ie. ip,range)")
	cmd.Flags().StringVarP(alertListFilter.ValueEquals, "value", "v", "", "the value to match for in the specified scope")
	cmd.Flags().StringVar(alertListFilter.OriginEquals, "origin", "", fmt.Sprintf("the value to match for the specified origin (%s ...)", strings.Join(types.GetOrigins(), ",")))
	cmd.Flags().BoolVar(contained, "contained", false, "query decisions contained by range")
	cmd.Flags().BoolVarP(&printMachine, "machine", "m", false, "print machines that sent alerts")
	cmd.Flags().IntVarP(limit, "limit", "l", 50, "limit size of alerts list table (0 to view all alerts)")

	return cmd
}

func (cli cliAlerts) NewDeleteCmd() *cobra.Command {
	var ActiveDecision *bool
	var AlertDeleteAll bool
	var delAlertByID string
	contained := new(bool)
	var alertDeleteFilter = apiclient.AlertsDeleteOpts{
		ScopeEquals:    new(string),
		ValueEquals:    new(string),
		ScenarioEquals: new(string),
		IPEquals:       new(string),
		RangeEquals:    new(string),
	}
	cmd := &cobra.Command{
		Use: "delete [filters] [--all]",
		Short: `Delete alerts
/!\ This command can be use only on the same machine than the local API.`,
		Example: `cscli alerts delete --ip 1.2.3.4
cscli alerts delete --range 1.2.3.0/24
cscli alerts delete -s crowdsecurity/ssh-bf"`,
		DisableAutoGenTag: true,
		Aliases:           []string{"remove"},
		Args:              cobra.ExactArgs(0),
		PreRunE: func(cmd *cobra.Command, args []string) error {
			if AlertDeleteAll {
				return nil
			}
			if *alertDeleteFilter.ScopeEquals == "" && *alertDeleteFilter.ValueEquals == "" &&
				*alertDeleteFilter.ScenarioEquals == "" && *alertDeleteFilter.IPEquals == "" &&
				*alertDeleteFilter.RangeEquals == "" && delAlertByID == "" {
				_ = cmd.Usage()
				return fmt.Errorf("at least one filter or --all must be specified")
			}

			return nil
		},
		RunE: func(cmd *cobra.Command, args []string) error {
			var err error

			if !AlertDeleteAll {
				if err := manageCliDecisionAlerts(alertDeleteFilter.IPEquals, alertDeleteFilter.RangeEquals,
					alertDeleteFilter.ScopeEquals, alertDeleteFilter.ValueEquals); err != nil {
					printHelp(cmd)
					return err
				}
				if ActiveDecision != nil {
					alertDeleteFilter.ActiveDecisionEquals = ActiveDecision
				}

				if *alertDeleteFilter.ScopeEquals == "" {
					alertDeleteFilter.ScopeEquals = nil
				}
				if *alertDeleteFilter.ValueEquals == "" {
					alertDeleteFilter.ValueEquals = nil
				}
				if *alertDeleteFilter.ScenarioEquals == "" {
					alertDeleteFilter.ScenarioEquals = nil
				}
				if *alertDeleteFilter.IPEquals == "" {
					alertDeleteFilter.IPEquals = nil
				}
				if *alertDeleteFilter.RangeEquals == "" {
					alertDeleteFilter.RangeEquals = nil
				}
				if contained != nil && *contained {
					alertDeleteFilter.Contains = new(bool)
				}
				limit := 0
				alertDeleteFilter.Limit = &limit
			} else {
				limit := 0
				alertDeleteFilter = apiclient.AlertsDeleteOpts{Limit: &limit}
			}

			var alerts *models.DeleteAlertsResponse
			if delAlertByID == "" {
				alerts, _, err = Client.Alerts.Delete(context.Background(), alertDeleteFilter)
				if err != nil {
					return fmt.Errorf("unable to delete alerts : %v", err)
				}
			} else {
				alerts, _, err = Client.Alerts.DeleteOne(context.Background(), delAlertByID)
				if err != nil {
					return fmt.Errorf("unable to delete alert: %v", err)
				}
			}
			log.Infof("%s alert(s) deleted", alerts.NbDeleted)

			return nil
		},
	}
	cmd.Flags().SortFlags = false
	cmd.Flags().StringVar(alertDeleteFilter.ScopeEquals, "scope", "", "the scope (ie. ip,range)")
	cmd.Flags().StringVarP(alertDeleteFilter.ValueEquals, "value", "v", "", "the value to match for in the specified scope")
	cmd.Flags().StringVarP(alertDeleteFilter.ScenarioEquals, "scenario", "s", "", "the scenario (ie. crowdsecurity/ssh-bf)")
	cmd.Flags().StringVarP(alertDeleteFilter.IPEquals, "ip", "i", "", "Source ip (shorthand for --scope ip --value <IP>)")
	cmd.Flags().StringVarP(alertDeleteFilter.RangeEquals, "range", "r", "", "Range source ip (shorthand for --scope range --value <RANGE>)")
	cmd.Flags().StringVar(&delAlertByID, "id", "", "alert ID")
	cmd.Flags().BoolVarP(&AlertDeleteAll, "all", "a", false, "delete all alerts")
	cmd.Flags().BoolVar(contained, "contained", false, "query decisions contained by range")
	return cmd
}

func (cli cliAlerts) NewInspectCmd() *cobra.Command {
	var details bool
	cmd := &cobra.Command{
		Use:               `inspect "alert_id"`,
		Short:             `Show info about an alert`,
		Example:           `cscli alerts inspect 123`,
		DisableAutoGenTag: true,
		RunE: func(cmd *cobra.Command, args []string) error {
			if len(args) == 0 {
				printHelp(cmd)
				return fmt.Errorf("missing alert_id")
			}
			for _, alertID := range args {
				id, err := strconv.Atoi(alertID)
				if err != nil {
					return fmt.Errorf("bad alert id %s", alertID)
				}
				alert, _, err := Client.Alerts.GetByID(context.Background(), id)
				if err != nil {
					return fmt.Errorf("can't find alert with id %s: %s", alertID, err)
				}
				switch csConfig.Cscli.Output {
				case "human":
					if err := DisplayOneAlert(alert, details); err != nil {
						continue
					}
				case "json":
					data, err := json.MarshalIndent(alert, "", "  ")
					if err != nil {
						return fmt.Errorf("unable to marshal alert with id %s: %s", alertID, err)
					}
					fmt.Printf("%s\n", string(data))
				case "raw":
					data, err := yaml.Marshal(alert)
					if err != nil {
						return fmt.Errorf("unable to marshal alert with id %s: %s", alertID, err)
					}
					fmt.Printf("%s\n", string(data))
				}
			}

			return nil
		},
	}
	cmd.Flags().SortFlags = false
	cmd.Flags().BoolVarP(&details, "details", "d", false, "show alerts with events")

	return cmd
}

func (cli cliAlerts) NewFlushCmd() *cobra.Command {
	var maxItems int
	var maxAge string
	cmd := &cobra.Command{
		Use: `flush`,
		Short: `Flush alerts
/!\ This command can be used only on the same machine than the local API`,
		Example:           `cscli alerts flush --max-items 1000 --max-age 7d`,
		DisableAutoGenTag: true,
		RunE: func(cmd *cobra.Command, args []string) error {
			var err error
			if err := require.LAPI(csConfig); err != nil {
				return err
			}
			dbClient, err = database.NewClient(csConfig.DbConfig)
			if err != nil {
				return fmt.Errorf("unable to create new database client: %s", err)
			}
			log.Info("Flushing alerts. !! This may take a long time !!")
			err = dbClient.FlushAlerts(maxAge, maxItems)
			if err != nil {
				return fmt.Errorf("unable to flush alerts: %s", err)
			}
			log.Info("Alerts flushed")

			return nil
		},
	}

	cmd.Flags().SortFlags = false
	cmd.Flags().IntVar(&maxItems, "max-items", 5000, "Maximum number of alert items to keep in the database")
	cmd.Flags().StringVar(&maxAge, "max-age", "7d", "Maximum age of alert items to keep in the database")

	return cmd
}