//go:build mgmt
// +build mgmt

package extensions

import (
	"context"
	"encoding/json"
	"io"
	"net/http"
	"time"

	"github.com/gorilla/mux"
	"github.com/opencontainers/go-digest"

	"zotregistry.io/zot/pkg/api/config"
	"zotregistry.io/zot/pkg/api/constants"
	zcommon "zotregistry.io/zot/pkg/common"
	"zotregistry.io/zot/pkg/log"
	"zotregistry.io/zot/pkg/meta/repodb"
	"zotregistry.io/zot/pkg/meta/signatures"
	"zotregistry.io/zot/pkg/scheduler"
)

const (
	ConfigResource     = "config"
	SignaturesResource = "signatures"
)

type HTPasswd struct {
	Path string `json:"path,omitempty"`
}

type BearerConfig struct {
	Realm   string `json:"realm,omitempty"`
	Service string `json:"service,omitempty"`
}

type OpenIDProviderConfig struct{}

type OpenIDConfig struct {
	Providers map[string]OpenIDProviderConfig `json:"providers,omitempty" mapstructure:"providers"`
}

type Auth struct {
	HTPasswd *HTPasswd     `json:"htpasswd,omitempty" mapstructure:"htpasswd"`
	Bearer   *BearerConfig `json:"bearer,omitempty" mapstructure:"bearer"`
	LDAP     *struct {
		Address string `json:"address,omitempty" mapstructure:"address"`
	} `json:"ldap,omitempty" mapstructure:"ldap"`
	OpenID *OpenIDConfig `json:"openid,omitempty" mapstructure:"openid"`
}

type StrippedConfig struct {
	DistSpecVersion string `json:"distSpecVersion" mapstructure:"distSpecVersion"`
	BinaryType      string `json:"binaryType" mapstructure:"binaryType"`
	HTTP            struct {
		Auth *Auth `json:"auth,omitempty" mapstructure:"auth"`
	} `json:"http" mapstructure:"http"`
}

func IsBuiltWithMGMTExtension() bool {
	return true
}

func (auth Auth) MarshalJSON() ([]byte, error) {
	type localAuth Auth

	if auth.Bearer == nil && auth.LDAP == nil &&
		auth.HTPasswd.Path == "" &&
		(auth.OpenID == nil || len(auth.OpenID.Providers) == 0) {
		auth.HTPasswd = nil
		auth.OpenID = nil

		return json.Marshal((localAuth)(auth))
	}

	if auth.HTPasswd.Path == "" && auth.LDAP == nil {
		auth.HTPasswd = nil
	} else {
		auth.HTPasswd.Path = ""
	}

	if auth.OpenID != nil && len(auth.OpenID.Providers) == 0 {
		auth.OpenID = nil
	}

	auth.LDAP = nil

	return json.Marshal((localAuth)(auth))
}

type mgmt struct {
	config *config.Config
	log    log.Logger
}

func (mgmt *mgmt) handler() http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		var resource string

		if queryHasParams(r.URL.Query(), []string{"resource"}) {
			resource = r.URL.Query().Get("resource")
		} else {
			resource = ConfigResource // default value of "resource" query param
		}

		switch resource {
		case ConfigResource:
			if r.Method == http.MethodGet {
				mgmt.HandleGetConfig(w, r)
			} else {
				w.WriteHeader(http.StatusBadRequest)
			}

			return
		case SignaturesResource:
			if r.Method == http.MethodPost {
				HandleCertificatesAndPublicKeysUploads(w, r) //nolint: contextcheck
			} else {
				w.WriteHeader(http.StatusBadRequest)
			}

			return
		default:
			w.WriteHeader(http.StatusBadRequest)

			return
		}
	})
}

func SetupMgmtRoutes(config *config.Config, router *mux.Router, log log.Logger) {
	if config.Extensions.Mgmt != nil && *config.Extensions.Mgmt.Enable {
		log.Info().Msg("setting up mgmt routes")

		mgmt := mgmt{config: config, log: log}

		allowedMethods := zcommon.AllowedMethods(http.MethodGet, http.MethodPost)

		mgmtRouter := router.PathPrefix(constants.ExtMgmt).Subrouter()
		mgmtRouter.Use(zcommon.ACHeadersHandler(allowedMethods...))
		mgmtRouter.Use(zcommon.AddExtensionSecurityHeaders())
		mgmtRouter.Methods(allowedMethods...).Handler(mgmt.handler())
	}
}

// mgmtHandler godoc
// @Summary Get current server configuration
// @Description Get current server configuration
// @Router 	/v2/_zot/ext/mgmt [get]
// @Accept  json
// @Produce json
// @Param 	resource 	 query 	 string			false	"specify resource" Enums(config)
// @Success 200 {object} 	extensions.StrippedConfig
// @Failure 500 {string} 	string 				"internal server error".
func (mgmt *mgmt) HandleGetConfig(w http.ResponseWriter, r *http.Request) {
	sanitizedConfig := mgmt.config.Sanitize()

	buf, err := zcommon.MarshalThroughStruct(sanitizedConfig, &StrippedConfig{})
	if err != nil {
		mgmt.log.Error().Err(err).Msg("mgmt: couldn't marshal config response")
		w.WriteHeader(http.StatusInternalServerError)
	}

	_, _ = w.Write(buf)
}

// mgmtHandler godoc
// @Summary Upload certificates and public keys for verifying signatures
// @Description Upload certificates and public keys for verifying signatures
// @Router 	/v2/_zot/ext/mgmt [post]
// @Accept  octet-stream
// @Produce json
// @Param 	resource 	 query 	 string 		true	"specify resource" Enums(signatures)
// @Param 	tool 	 query 	 string 		true	"specify signing tool" Enums(cosign, notation)
// @Param   truststoreType     	 query    string			false	"truststore type"
// @Param   truststoreName     	 query    string			false	"truststore name"
// @Param   requestBody		body	string		true	"Public key or Certificate content"
// @Success 200 {string}    string              "ok"
// @Failure 400 {string} 	string 				"bad request".
// @Failure 500 {string} 	string 				"internal server error".
func HandleCertificatesAndPublicKeysUploads(response http.ResponseWriter, request *http.Request) {
	if !queryHasParams(request.URL.Query(), []string{"tool"}) {
		response.WriteHeader(http.StatusBadRequest)

		return
	}

	body, err := io.ReadAll(request.Body)
	if err != nil {
		response.WriteHeader(http.StatusInternalServerError)

		return
	}

	tool := request.URL.Query().Get("tool")

	switch tool {
	case signatures.CosignSignature:
		err := signatures.UploadPublicKey(body)
		if err != nil {
			response.WriteHeader(http.StatusInternalServerError)

			return
		}
	case signatures.NotationSignature:
		var truststoreType string

		if !queryHasParams(request.URL.Query(), []string{"truststoreName"}) {
			response.WriteHeader(http.StatusBadRequest)

			return
		}

		if queryHasParams(request.URL.Query(), []string{"truststoreType"}) {
			truststoreType = request.URL.Query().Get("truststoreType")
		} else {
			truststoreType = "ca" // default value of "truststoreType" query param
		}

		truststoreName := request.URL.Query().Get("truststoreName")

		if truststoreType == "" || truststoreName == "" {
			response.WriteHeader(http.StatusBadRequest)

			return
		}

		err = signatures.UploadCertificate(body, truststoreType, truststoreName)
		if err != nil {
			response.WriteHeader(http.StatusInternalServerError)

			return
		}
	default:
		response.WriteHeader(http.StatusBadRequest)

		return
	}

	response.WriteHeader(http.StatusOK)
}

func EnablePeriodicSignaturesVerification(config *config.Config, taskScheduler *scheduler.Scheduler,
	repoDB repodb.RepoDB, log log.Logger,
) {
	if config.Extensions.Search != nil && *config.Extensions.Search.Enable {
		ctx := context.Background()

		repos, err := repoDB.GetMultipleRepoMeta(ctx, func(repoMeta repodb.RepoMetadata) bool {
			return true
		}, repodb.PageInput{})
		if err != nil {
			return
		}

		generator := &taskGeneratorSigValidity{
			repos:     repos,
			repoDB:    repoDB,
			repoIndex: -1,
			log:       log,
		}

		numberOfHours := 2
		interval := time.Duration(numberOfHours) * time.Minute
		taskScheduler.SubmitGenerator(generator, interval, scheduler.MediumPriority)
	}
}

type taskGeneratorSigValidity struct {
	repos     []repodb.RepoMetadata
	repoDB    repodb.RepoDB
	repoIndex int
	done      bool
	log       log.Logger
}

func (gen *taskGeneratorSigValidity) Next() (scheduler.Task, error) {
	gen.repoIndex++

	if gen.repoIndex >= len(gen.repos) {
		gen.done = true

		return nil, nil
	}

	return NewValidityTask(gen.repoDB, gen.repos[gen.repoIndex], gen.log), nil
}

func (gen *taskGeneratorSigValidity) IsDone() bool {
	return gen.done
}

func (gen *taskGeneratorSigValidity) Reset() {
	gen.done = false
	gen.repoIndex = -1
	ctx := context.Background()

	repos, err := gen.repoDB.GetMultipleRepoMeta(ctx, func(repoMeta repodb.RepoMetadata) bool {
		return true
	}, repodb.PageInput{})
	if err != nil {
		return
	}

	gen.repos = repos
}

type validityTask struct {
	repoDB repodb.RepoDB
	repo   repodb.RepoMetadata
	log    log.Logger
}

func NewValidityTask(repoDB repodb.RepoDB, repo repodb.RepoMetadata, log log.Logger) *validityTask {
	return &validityTask{repoDB, repo, log}
}

func (validityT *validityTask) DoWork() error {
	validityT.log.Info().Msg("updating signatures validity")

	for signedManifest, sigs := range validityT.repo.Signatures {
		if len(sigs[signatures.CosignSignature]) != 0 || len(sigs[signatures.NotationSignature]) != 0 {
			err := validityT.repoDB.UpdateSignaturesValidity(validityT.repo.Name, digest.Digest(signedManifest))
			if err != nil {
				validityT.log.Info().Msg("error while verifying signatures")

				return err
			}
		}
	}

	validityT.log.Info().Msg("verifying signatures successfully completed")

	return nil
}