package cli

import (
	"context"
	"fmt"
	"net/http"

	glob "github.com/bmatcuk/doublestar/v4"
	"github.com/fsnotify/fsnotify"
	"github.com/mitchellh/mapstructure"
	distspec "github.com/opencontainers/distribution-spec/specs-go"
	"github.com/rs/zerolog/log"
	"github.com/spf13/cobra"
	"github.com/spf13/viper"
	"zotregistry.io/zot/errors"
	"zotregistry.io/zot/pkg/api"
	"zotregistry.io/zot/pkg/api/config"
	"zotregistry.io/zot/pkg/extensions/monitoring"
	"zotregistry.io/zot/pkg/storage"
)

// metadataConfig reports metadata after parsing, which we use to track
// errors.
func metadataConfig(md *mapstructure.Metadata) viper.DecoderConfigOption {
	return func(c *mapstructure.DecoderConfig) {
		c.Metadata = md
	}
}

func newServeCmd(conf *config.Config) *cobra.Command {
	// "serve"
	serveCmd := &cobra.Command{
		Use:     "serve <config>",
		Aliases: []string{"serve"},
		Short:   "`serve` stores and distributes OCI images",
		Long:    "`serve` stores and distributes OCI images",
		Run: func(cmd *cobra.Command, args []string) {
			if len(args) > 0 {
				LoadConfiguration(conf, args[0])
			}

			ctlr := api.NewController(conf)

			// creates a new file watcher
			watcher, err := fsnotify.NewWatcher()
			if err != nil {
				panic(err)
			}
			defer watcher.Close()

			done := make(chan bool)
			// run watcher
			go func() {
				go func() {
					for {
						select {
						// watch for events
						case event := <-watcher.Events:
							if event.Op == fsnotify.Write {
								log.Info().Msg("config file changed, trying to reload accessControl config")
								newConfig := config.New()
								LoadConfiguration(newConfig, args[0])
								ctlr.Config.AccessControl = newConfig.AccessControl
							}
						// watch for errors
						case err := <-watcher.Errors:
							log.Error().Err(err).Msgf("FsNotify error while watching config %s", args[0])
							panic(err)
						}
					}
				}()

				if err := watcher.Add(args[0]); err != nil {
					log.Error().Err(err).Msgf("error adding config file %s to FsNotify watcher", args[0])
					panic(err)
				}
				<-done
			}()

			if err := ctlr.Run(); err != nil {
				panic(err)
			}
		},
	}

	return serveCmd
}

func newScrubCmd(conf *config.Config) *cobra.Command {
	// "scrub"
	scrubCmd := &cobra.Command{
		Use:     "scrub <config>",
		Aliases: []string{"scrub"},
		Short:   "`scrub` checks manifest/blob integrity",
		Long:    "`scrub` checks manifest/blob integrity",
		Run: func(cmd *cobra.Command, args []string) {
			if len(args) > 0 {
				LoadConfiguration(conf, args[0])
			} else {
				if err := cmd.Usage(); err != nil {
					panic(err)
				}

				return
			}

			// checking if the server is  already running
			req, err := http.NewRequestWithContext(context.Background(),
				http.MethodGet,
				fmt.Sprintf("http://%s:%s/v2", conf.HTTP.Address, conf.HTTP.Port),
				nil)
			if err != nil {
				log.Error().Err(err).Msg("unable to create a new http request")
				panic(err)
			}

			response, err := http.DefaultClient.Do(req)
			if err == nil {
				response.Body.Close()
				log.Info().Msg("The server is running, in order to perform the scrub command the server should be shut down")
				panic("Error: server is running")
			} else {
				// server is down
				ctlr := api.NewController(conf)
				ctlr.Metrics = monitoring.NewMetricsServer(false, ctlr.Log)

				if err := ctlr.InitImageStore(); err != nil {
					panic(err)
				}

				result, err := ctlr.StoreController.CheckAllBlobsIntegrity()
				if err != nil {
					panic(err)
				}

				result.PrintScrubResults(cmd.OutOrStdout())
			}
		},
	}

	return scrubCmd
}

func newVerifyCmd(conf *config.Config) *cobra.Command {
	// verify
	verifyCmd := &cobra.Command{
		Use:     "verify <config>",
		Aliases: []string{"verify"},
		Short:   "`verify` validates a zot config file",
		Long:    "`verify` validates a zot config file",
		Run: func(cmd *cobra.Command, args []string) {
			if len(args) > 0 {
				LoadConfiguration(conf, args[0])
				log.Info().Msgf("Config file %s is valid", args[0])
			}
		},
	}

	return verifyCmd
}

// "zot" - registry server.
func NewServerRootCmd() *cobra.Command {
	showVersion := false
	conf := config.New()

	rootCmd := &cobra.Command{
		Use:   "zot",
		Short: "`zot`",
		Long:  "`zot`",
		Run: func(cmd *cobra.Command, args []string) {
			if showVersion {
				log.Info().Str("distribution-spec", distspec.Version).Str("commit", config.Commit).
					Str("binary-type", config.BinaryType).Str("go version", config.GoVersion).Msg("version")
			} else {
				_ = cmd.Usage()
				cmd.SilenceErrors = false
			}
		},
	}

	// "serve"
	rootCmd.AddCommand(newServeCmd(conf))
	// "verify"
	rootCmd.AddCommand(newVerifyCmd(conf))
	// "scrub"
	rootCmd.AddCommand(newScrubCmd(conf))
	// "version"
	rootCmd.Flags().BoolVarP(&showVersion, "version", "v", false, "show the version and exit")

	return rootCmd
}

// "zli" - client-side cli.
func NewCliRootCmd() *cobra.Command {
	showVersion := false

	rootCmd := &cobra.Command{
		Use:   "zli",
		Short: "`zli`",
		Long:  "`zli`",
		Run: func(cmd *cobra.Command, args []string) {
			if showVersion {
				log.Info().Str("distribution-spec", distspec.Version).Str("commit", config.Commit).
					Str("binary-type", config.BinaryType).Str("go version", config.GoVersion).Msg("version")
			} else {
				_ = cmd.Usage()
				cmd.SilenceErrors = false
			}
		},
	}

	// additional cmds
	enableCli(rootCmd)
	// "version"
	rootCmd.Flags().BoolVarP(&showVersion, "version", "v", false, "show the version and exit")

	return rootCmd
}

func validateConfiguration(config *config.Config) {
	// check authorization config, it should have basic auth enabled or ldap
	if config.HTTP.RawAccessControl != nil {
		if config.HTTP.Auth == nil || (config.HTTP.Auth.HTPasswd.Path == "" && config.HTTP.Auth.LDAP == nil) {
			log.Error().Err(errors.ErrBadConfig).
				Msg("access control config requires httpasswd or ldap authentication to be enabled")
			panic(errors.ErrBadConfig)
		}
	}

	if len(config.Storage.StorageDriver) != 0 {
		// enforce s3 driver in case of using storage driver
		if config.Storage.StorageDriver["name"] != storage.S3StorageDriverName {
			log.Error().Err(errors.ErrBadConfig).Msgf("unsupported storage driver: %s", config.Storage.StorageDriver["name"])
			panic(errors.ErrBadConfig)
		}

		// enforce filesystem storage in case sync feature is enabled
		if config.Extensions != nil && config.Extensions.Sync != nil {
			log.Error().Err(errors.ErrBadConfig).Msg("sync supports only filesystem storage")
			panic(errors.ErrBadConfig)
		}
	}

	// check glob patterns in sync config are compilable
	if config.Extensions != nil && config.Extensions.Sync != nil {
		for _, regCfg := range config.Extensions.Sync.Registries {
			if regCfg.Content != nil {
				for _, content := range regCfg.Content {
					ok := glob.ValidatePattern(content.Prefix)
					if !ok {
						log.Error().Err(glob.ErrBadPattern).Str("pattern", content.Prefix).Msg("sync pattern could not be compiled")
						panic(errors.ErrBadConfig)
					}
				}
			}
		}
	}

	// enforce s3 driver on subpaths in case of using storage driver
	if config.Storage.SubPaths != nil {
		if len(config.Storage.SubPaths) > 0 {
			subPaths := config.Storage.SubPaths

			for route, storageConfig := range subPaths {
				if len(storageConfig.StorageDriver) != 0 {
					if storageConfig.StorageDriver["name"] != storage.S3StorageDriverName {
						log.Error().Err(errors.ErrBadConfig).Str("subpath",
							route).Msgf("unsupported storage driver: %s", storageConfig.StorageDriver["name"])
						panic(errors.ErrBadConfig)
					}
				}
			}
		}
	}

	// check glob patterns in authz config are compilable
	if config.AccessControl != nil {
		for pattern := range config.AccessControl.Repositories {
			ok := glob.ValidatePattern(pattern)
			if !ok {
				log.Error().Err(glob.ErrBadPattern).Str("pattern", pattern).Msg("authorization pattern could not be compiled")
				panic(errors.ErrBadConfig)
			}
		}
	}
}

func LoadConfiguration(config *config.Config, configPath string) {
	// Default is dot (.) but because we allow glob patterns in authz
	// we need another key delimiter.
	viperInstance := viper.NewWithOptions(viper.KeyDelimiter("::"))

	viperInstance.SetConfigFile(configPath)

	if err := viperInstance.ReadInConfig(); err != nil {
		log.Error().Err(err).Msg("error while reading configuration")
		panic(err)
	}

	metaData := &mapstructure.Metadata{}
	if err := viperInstance.Unmarshal(&config, metadataConfig(metaData)); err != nil {
		log.Error().Err(err).Msg("error while unmarshalling new config")
		panic(err)
	}

	if len(metaData.Keys) == 0 || len(metaData.Unused) > 0 {
		log.Error().Err(errors.ErrBadConfig).Msg("bad configuration, retry writing it")
		panic(errors.ErrBadConfig)
	}

	err := config.LoadAccessControlConfig(viperInstance)
	if err != nil {
		log.Error().Err(err).Msg("unable to unmarshal config's accessControl")
		panic(err)
	}

	// various config checks
	validateConfiguration(config)

	// defaults
	defaultTLSVerify := true

	if config.Extensions != nil && config.Extensions.Sync != nil {
		for id, regCfg := range config.Extensions.Sync.Registries {
			if regCfg.TLSVerify == nil {
				config.Extensions.Sync.Registries[id].TLSVerify = &defaultTLSVerify
			}
		}
	}
}