package main

import (
	"context"
	"errors"
	"fmt"
	"net/url"
	"os"
	"slices"
	"sort"
	"strings"

	"github.com/go-openapi/strfmt"
	log "github.com/sirupsen/logrus"
	"github.com/spf13/cobra"
	"gopkg.in/yaml.v3"

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

	"github.com/crowdsecurity/crowdsec/cmd/crowdsec-cli/require"
	"github.com/crowdsecurity/crowdsec/pkg/alertcontext"
	"github.com/crowdsecurity/crowdsec/pkg/apiclient"
	"github.com/crowdsecurity/crowdsec/pkg/csconfig"
	"github.com/crowdsecurity/crowdsec/pkg/cwhub"
	"github.com/crowdsecurity/crowdsec/pkg/exprhelpers"
	"github.com/crowdsecurity/crowdsec/pkg/models"
	"github.com/crowdsecurity/crowdsec/pkg/parser"
)

const LAPIURLPrefix = "v1"

type cliLapi struct {
	cfg configGetter
}

func NewCLILapi(cfg configGetter) *cliLapi {
	return &cliLapi{
		cfg: cfg,
	}
}

func (cli *cliLapi) status() error {
	cfg := cli.cfg()
	password := strfmt.Password(cfg.API.Client.Credentials.Password)
	login := cfg.API.Client.Credentials.Login

	origURL := cfg.API.Client.Credentials.URL

	apiURL, err := url.Parse(origURL)
	if err != nil {
		return fmt.Errorf("parsing api url: %w", err)
	}

	hub, err := require.Hub(cfg, nil, nil)
	if err != nil {
		return err
	}

	scenarios, err := hub.GetInstalledNamesByType(cwhub.SCENARIOS)
	if err != nil {
		return fmt.Errorf("failed to get scenarios: %w", err)
	}

	Client, err = apiclient.NewDefaultClient(apiURL,
		LAPIURLPrefix,
		fmt.Sprintf("crowdsec/%s", version.String()),
		nil)
	if err != nil {
		return fmt.Errorf("init default client: %w", err)
	}

	t := models.WatcherAuthRequest{
		MachineID: &login,
		Password:  &password,
		Scenarios: scenarios,
	}

	log.Infof("Loaded credentials from %s", cfg.API.Client.CredentialsFilePath)
	// use the original string because apiURL would print 'http://unix/'
	log.Infof("Trying to authenticate with username %s on %s", login, origURL)

	_, _, err = Client.Auth.AuthenticateWatcher(context.Background(), t)
	if err != nil {
		return fmt.Errorf("failed to authenticate to Local API (LAPI): %w", err)
	}

	log.Infof("You can successfully interact with Local API (LAPI)")

	return nil
}

func (cli *cliLapi) register(apiURL string, outputFile string, machine string) error {
	var err error

	lapiUser := machine
	cfg := cli.cfg()

	if lapiUser == "" {
		lapiUser, err = generateID("")
		if err != nil {
			return fmt.Errorf("unable to generate machine id: %w", err)
		}
	}

	password := strfmt.Password(generatePassword(passwordLength))

	apiurl, err := prepareAPIURL(cfg.API.Client, apiURL)
	if err != nil {
		return fmt.Errorf("parsing api url: %w", err)
	}

	_, err = apiclient.RegisterClient(&apiclient.Config{
		MachineID:     lapiUser,
		Password:      password,
		UserAgent:     fmt.Sprintf("crowdsec/%s", version.String()),
		URL:           apiurl,
		VersionPrefix: LAPIURLPrefix,
	}, nil)
	if err != nil {
		return fmt.Errorf("api client register: %w", err)
	}

	log.Printf("Successfully registered to Local API (LAPI)")

	var dumpFile string

	if outputFile != "" {
		dumpFile = outputFile
	} else if cfg.API.Client.CredentialsFilePath != "" {
		dumpFile = cfg.API.Client.CredentialsFilePath
	} else {
		dumpFile = ""
	}

	apiCfg := csconfig.ApiCredentialsCfg{
		Login:    lapiUser,
		Password: password.String(),
		URL:      apiURL,
	}

	apiConfigDump, err := yaml.Marshal(apiCfg)
	if err != nil {
		return fmt.Errorf("unable to marshal api credentials: %w", err)
	}

	if dumpFile != "" {
		err = os.WriteFile(dumpFile, apiConfigDump, 0o600)
		if err != nil {
			return fmt.Errorf("write api credentials to '%s' failed: %w", dumpFile, err)
		}

		log.Printf("Local API credentials written to '%s'", dumpFile)
	} else {
		fmt.Printf("%s\n", string(apiConfigDump))
	}

	log.Warning(ReloadMessage())

	return nil
}

// prepareAPIURL checks/fixes a LAPI connection url (http, https or socket) and returns an URL struct
func prepareAPIURL(clientCfg *csconfig.LocalApiClientCfg, apiURL string) (*url.URL, error) {
	if apiURL == "" {
		if clientCfg == nil || clientCfg.Credentials == nil || clientCfg.Credentials.URL == "" {
			return nil, errors.New("no Local API URL. Please provide it in your configuration or with the -u parameter")
		}

		apiURL = clientCfg.Credentials.URL
	}

	// URL needs to end with /, but user doesn't care
	if !strings.HasSuffix(apiURL, "/") {
		apiURL += "/"
	}

	// URL needs to start with http://, but user doesn't care
	if !strings.HasPrefix(apiURL, "http://") && !strings.HasPrefix(apiURL, "https://") && !strings.HasPrefix(apiURL, "/") {
		apiURL = "http://" + apiURL
	}

	return url.Parse(apiURL)
}

func (cli *cliLapi) newStatusCmd() *cobra.Command {
	cmdLapiStatus := &cobra.Command{
		Use:               "status",
		Short:             "Check authentication to Local API (LAPI)",
		Args:              cobra.MinimumNArgs(0),
		DisableAutoGenTag: true,
		RunE: func(_ *cobra.Command, _ []string) error {
			return cli.status()
		},
	}

	return cmdLapiStatus
}

func (cli *cliLapi) newRegisterCmd() *cobra.Command {
	var (
		apiURL     string
		outputFile string
		machine    string
	)

	cmd := &cobra.Command{
		Use:   "register",
		Short: "Register a machine to Local API (LAPI)",
		Long: `Register your machine to the Local API (LAPI).
Keep in mind the machine needs to be validated by an administrator on LAPI side to be effective.`,
		Args:              cobra.MinimumNArgs(0),
		DisableAutoGenTag: true,
		RunE: func(_ *cobra.Command, _ []string) error {
			return cli.register(apiURL, outputFile, machine)
		},
	}

	flags := cmd.Flags()
	flags.StringVarP(&apiURL, "url", "u", "", "URL of the API (ie. http://127.0.0.1)")
	flags.StringVarP(&outputFile, "file", "f", "", "output file destination")
	flags.StringVar(&machine, "machine", "", "Name of the machine to register with")

	return cmd
}

func (cli *cliLapi) NewCommand() *cobra.Command {
	cmd := &cobra.Command{
		Use:               "lapi [action]",
		Short:             "Manage interaction with Local API (LAPI)",
		Args:              cobra.MinimumNArgs(1),
		DisableAutoGenTag: true,
		PersistentPreRunE: func(_ *cobra.Command, _ []string) error {
			if err := cli.cfg().LoadAPIClient(); err != nil {
				return fmt.Errorf("loading api client: %w", err)
			}
			return nil
		},
	}

	cmd.AddCommand(cli.newRegisterCmd())
	cmd.AddCommand(cli.newStatusCmd())
	cmd.AddCommand(cli.newContextCmd())

	return cmd
}

func (cli *cliLapi) addContext(key string, values []string) error {
	cfg := cli.cfg()

	if err := alertcontext.ValidateContextExpr(key, values); err != nil {
		return fmt.Errorf("invalid context configuration: %w", err)
	}

	if _, ok := cfg.Crowdsec.ContextToSend[key]; !ok {
		cfg.Crowdsec.ContextToSend[key] = make([]string, 0)

		log.Infof("key '%s' added", key)
	}

	data := cfg.Crowdsec.ContextToSend[key]

	for _, val := range values {
		if !slices.Contains(data, val) {
			log.Infof("value '%s' added to key '%s'", val, key)
			data = append(data, val)
		}

		cfg.Crowdsec.ContextToSend[key] = data
	}

	if err := cfg.Crowdsec.DumpContextConfigFile(); err != nil {
		return err
	}

	return nil
}

func (cli *cliLapi) newContextAddCmd() *cobra.Command {
	var (
		keyToAdd    string
		valuesToAdd []string
	)

	cmd := &cobra.Command{
		Use:   "add",
		Short: "Add context to send with alerts. You must specify the output key with the expr value you want",
		Example: `cscli lapi context add --key source_ip --value evt.Meta.source_ip
cscli lapi context add --key file_source --value evt.Line.Src
cscli lapi context add --value evt.Meta.source_ip --value evt.Meta.target_user 
		`,
		DisableAutoGenTag: true,
		RunE: func(_ *cobra.Command, _ []string) error {
			hub, err := require.Hub(cli.cfg(), nil, nil)
			if err != nil {
				return err
			}

			if err = alertcontext.LoadConsoleContext(cli.cfg(), hub); err != nil {
				return fmt.Errorf("while loading context: %w", err)
			}

			if keyToAdd != "" {
				if err := cli.addContext(keyToAdd, valuesToAdd); err != nil {
					return err
				}
				return nil
			}

			for _, v := range valuesToAdd {
				keySlice := strings.Split(v, ".")
				key := keySlice[len(keySlice)-1]
				value := []string{v}
				if err := cli.addContext(key, value); err != nil {
					return err
				}
			}

			return nil
		},
	}

	flags := cmd.Flags()
	flags.StringVarP(&keyToAdd, "key", "k", "", "The key of the different values to send")
	flags.StringSliceVar(&valuesToAdd, "value", []string{}, "The expr fields to associate with the key")
	cmd.MarkFlagRequired("value")

	return cmd
}

func (cli *cliLapi) newContextStatusCmd() *cobra.Command {
	cmd := &cobra.Command{
		Use:               "status",
		Short:             "List context to send with alerts",
		DisableAutoGenTag: true,
		RunE: func(_ *cobra.Command, _ []string) error {
			cfg := cli.cfg()
			hub, err := require.Hub(cfg, nil, nil)
			if err != nil {
				return err
			}

			if err = alertcontext.LoadConsoleContext(cfg, hub); err != nil {
				return fmt.Errorf("while loading context: %w", err)
			}

			if len(cfg.Crowdsec.ContextToSend) == 0 {
				fmt.Println("No context found on this agent. You can use 'cscli lapi context add' to add context to your alerts.")
				return nil
			}

			dump, err := yaml.Marshal(cfg.Crowdsec.ContextToSend)
			if err != nil {
				return fmt.Errorf("unable to show context status: %w", err)
			}

			fmt.Print(string(dump))

			return nil
		},
	}

	return cmd
}

func (cli *cliLapi) newContextDetectCmd() *cobra.Command {
	var detectAll bool

	cmd := &cobra.Command{
		Use:   "detect",
		Short: "Detect available fields from the installed parsers",
		Example: `cscli lapi context detect --all
cscli lapi context detect crowdsecurity/sshd-logs
		`,
		DisableAutoGenTag: true,
		RunE: func(cmd *cobra.Command, args []string) error {
			cfg := cli.cfg()
			if !detectAll && len(args) == 0 {
				log.Infof("Please provide parsers to detect or --all flag.")
				printHelp(cmd)
			}

			// to avoid all the log.Info from the loaders functions
			log.SetLevel(log.WarnLevel)

			if err := exprhelpers.Init(nil); err != nil {
				return fmt.Errorf("failed to init expr helpers: %w", err)
			}

			hub, err := require.Hub(cfg, nil, nil)
			if err != nil {
				return err
			}

			csParsers := parser.NewParsers(hub)
			if csParsers, err = parser.LoadParsers(cfg, csParsers); err != nil {
				return fmt.Errorf("unable to load parsers: %w", err)
			}

			fieldByParsers := make(map[string][]string)
			for _, node := range csParsers.Nodes {
				if !detectAll && !slices.Contains(args, node.Name) {
					continue
				}
				if !detectAll {
					args = removeFromSlice(node.Name, args)
				}
				fieldByParsers[node.Name] = make([]string, 0)
				fieldByParsers[node.Name] = detectNode(node, *csParsers.Ctx)

				subNodeFields := detectSubNode(node, *csParsers.Ctx)
				for _, field := range subNodeFields {
					if !slices.Contains(fieldByParsers[node.Name], field) {
						fieldByParsers[node.Name] = append(fieldByParsers[node.Name], field)
					}
				}
			}

			fmt.Printf("Acquisition :\n\n")
			fmt.Printf("  - evt.Line.Module\n")
			fmt.Printf("  - evt.Line.Raw\n")
			fmt.Printf("  - evt.Line.Src\n")
			fmt.Println()

			parsersKey := make([]string, 0)
			for k := range fieldByParsers {
				parsersKey = append(parsersKey, k)
			}
			sort.Strings(parsersKey)

			for _, k := range parsersKey {
				if len(fieldByParsers[k]) == 0 {
					continue
				}
				fmt.Printf("%s :\n\n", k)
				values := fieldByParsers[k]
				sort.Strings(values)
				for _, value := range values {
					fmt.Printf("  - %s\n", value)
				}
				fmt.Println()
			}

			if len(args) > 0 {
				for _, parserNotFound := range args {
					log.Errorf("parser '%s' not found, can't detect fields", parserNotFound)
				}
			}

			return nil
		},
	}
	cmd.Flags().BoolVarP(&detectAll, "all", "a", false, "Detect evt field for all installed parser")

	return cmd
}

func (cli *cliLapi) newContextDeleteCmd() *cobra.Command {
	cmd := &cobra.Command{
		Use:               "delete",
		DisableAutoGenTag: true,
		RunE: func(_ *cobra.Command, _ []string) error {
			filePath := cli.cfg().Crowdsec.ConsoleContextPath
			if filePath == "" {
				filePath = "the context file"
			}
			fmt.Printf("Command 'delete' is deprecated, please manually edit %s.", filePath)

			return nil
		},
	}

	return cmd
}

func (cli *cliLapi) newContextCmd() *cobra.Command {
	cmd := &cobra.Command{
		Use:               "context [command]",
		Short:             "Manage context to send with alerts",
		DisableAutoGenTag: true,
		PersistentPreRunE: func(_ *cobra.Command, _ []string) error {
			cfg := cli.cfg()
			if err := cfg.LoadCrowdsec(); err != nil {
				fileNotFoundMessage := fmt.Sprintf("failed to open context file: open %s: no such file or directory", cfg.Crowdsec.ConsoleContextPath)
				if err.Error() != fileNotFoundMessage {
					return fmt.Errorf("unable to load CrowdSec agent configuration: %w", err)
				}
			}
			if cfg.DisableAgent {
				return errors.New("agent is disabled and lapi context can only be used on the agent")
			}

			return nil
		},
		Run: func(cmd *cobra.Command, _ []string) {
			printHelp(cmd)
		},
	}

	cmd.AddCommand(cli.newContextAddCmd())
	cmd.AddCommand(cli.newContextStatusCmd())
	cmd.AddCommand(cli.newContextDetectCmd())
	cmd.AddCommand(cli.newContextDeleteCmd())

	return cmd
}

func detectStaticField(grokStatics []parser.ExtraField) []string {
	ret := make([]string, 0)

	for _, static := range grokStatics {
		if static.Parsed != "" {
			fieldName := fmt.Sprintf("evt.Parsed.%s", static.Parsed)
			if !slices.Contains(ret, fieldName) {
				ret = append(ret, fieldName)
			}
		}

		if static.Meta != "" {
			fieldName := fmt.Sprintf("evt.Meta.%s", static.Meta)
			if !slices.Contains(ret, fieldName) {
				ret = append(ret, fieldName)
			}
		}

		if static.TargetByName != "" {
			fieldName := static.TargetByName
			if !strings.HasPrefix(fieldName, "evt.") {
				fieldName = "evt." + fieldName
			}

			if !slices.Contains(ret, fieldName) {
				ret = append(ret, fieldName)
			}
		}
	}

	return ret
}

func detectNode(node parser.Node, parserCTX parser.UnixParserCtx) []string {
	ret := make([]string, 0)

	if node.Grok.RunTimeRegexp != nil {
		for _, capturedField := range node.Grok.RunTimeRegexp.Names() {
			fieldName := fmt.Sprintf("evt.Parsed.%s", capturedField)
			if !slices.Contains(ret, fieldName) {
				ret = append(ret, fieldName)
			}
		}
	}

	if node.Grok.RegexpName != "" {
		grokCompiled, err := parserCTX.Grok.Get(node.Grok.RegexpName)
		// ignore error (parser does not exist?)
		if err == nil {
			for _, capturedField := range grokCompiled.Names() {
				fieldName := fmt.Sprintf("evt.Parsed.%s", capturedField)
				if !slices.Contains(ret, fieldName) {
					ret = append(ret, fieldName)
				}
			}
		}
	}

	if len(node.Grok.Statics) > 0 {
		staticsField := detectStaticField(node.Grok.Statics)
		for _, staticField := range staticsField {
			if !slices.Contains(ret, staticField) {
				ret = append(ret, staticField)
			}
		}
	}

	if len(node.Statics) > 0 {
		staticsField := detectStaticField(node.Statics)
		for _, staticField := range staticsField {
			if !slices.Contains(ret, staticField) {
				ret = append(ret, staticField)
			}
		}
	}

	return ret
}

func detectSubNode(node parser.Node, parserCTX parser.UnixParserCtx) []string {
	ret := make([]string, 0)

	for _, subnode := range node.LeavesNodes {
		if subnode.Grok.RunTimeRegexp != nil {
			for _, capturedField := range subnode.Grok.RunTimeRegexp.Names() {
				fieldName := fmt.Sprintf("evt.Parsed.%s", capturedField)
				if !slices.Contains(ret, fieldName) {
					ret = append(ret, fieldName)
				}
			}
		}

		if subnode.Grok.RegexpName != "" {
			grokCompiled, err := parserCTX.Grok.Get(subnode.Grok.RegexpName)
			if err == nil {
				// ignore error (parser does not exist?)
				for _, capturedField := range grokCompiled.Names() {
					fieldName := fmt.Sprintf("evt.Parsed.%s", capturedField)
					if !slices.Contains(ret, fieldName) {
						ret = append(ret, fieldName)
					}
				}
			}
		}

		if len(subnode.Grok.Statics) > 0 {
			staticsField := detectStaticField(subnode.Grok.Statics)
			for _, staticField := range staticsField {
				if !slices.Contains(ret, staticField) {
					ret = append(ret, staticField)
				}
			}
		}

		if len(subnode.Statics) > 0 {
			staticsField := detectStaticField(subnode.Statics)
			for _, staticField := range staticsField {
				if !slices.Contains(ret, staticField) {
					ret = append(ret, staticField)
				}
			}
		}
	}

	return ret
}