// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.

package app

import (
	"database/sql"
	"encoding/base64"
	"net/http"

	"github.com/pkg/errors"

	"github.com/mattermost/mattermost/server/v8/channels/store/sqlstore"
	"github.com/mattermost/mattermost/server/v8/platform/services/remotecluster"

	"github.com/mattermost/mattermost/server/public/model"
	"github.com/mattermost/mattermost/server/public/shared/mlog"
	"github.com/mattermost/mattermost/server/public/shared/request"
)

func (a *App) RegisterPluginForSharedChannels(rctx request.CTX, opts model.RegisterPluginOpts) (remoteID string, err error) {
	// check for pluginID already registered
	rc, err := a.Srv().Store().RemoteCluster().GetByPluginID(opts.PluginID)
	if err != nil {
		if !errors.Is(err, sql.ErrNoRows) {
			// anything other than not_found is unrecoverable
			return "", err
		}
	}

	// if plugin is already registered then treat this as an update.
	if rc != nil {
		// plugin was deleted at some point
		if rc.DeleteAt != 0 {
			rctx.Logger().Debug("Restoring plugin registration for Shared Channels",
				mlog.String("plugin_id", opts.PluginID),
				mlog.String("remote_id", rc.RemoteId),
			)

			rc.DeleteAt = 0
		} else {
			rctx.Logger().Debug("Plugin already registered for Shared Channels",
				mlog.String("plugin_id", opts.PluginID),
				mlog.String("remote_id", rc.RemoteId),
			)
		}

		rc.DisplayName = opts.Displayname
		rc.Options = opts.GetOptionFlags()

		if _, err = a.Srv().Store().RemoteCluster().Update(rc); err != nil {
			return "", err
		}
		return rc.RemoteId, nil
	}

	rc = &model.RemoteCluster{
		Name:        opts.Displayname,
		DisplayName: opts.Displayname,
		SiteURL:     model.SiteURLPlugin + opts.PluginID, // require a unique siteurl
		Token:       model.NewId(),
		CreatorId:   opts.CreatorID,
		PluginID:    opts.PluginID,
		Options:     opts.GetOptionFlags(),
	}

	rcSaved, err := a.Srv().Store().RemoteCluster().Save(rc)
	if err != nil {
		return "", err
	}

	rctx.Logger().Debug("Registered new plugin for Shared Channels",
		mlog.String("plugin_id", opts.PluginID),
		mlog.String("remote_id", rcSaved.RemoteId),
	)

	// ping the plugin remote immediately if the service is running
	// If the service is not available the ping will happen once the
	// service starts. This is expected since plugins start before the
	// service.
	rcService, _ := a.GetRemoteClusterService()
	if rcService != nil {
		rcService.PingNow(rcSaved)
	}

	return rcSaved.RemoteId, nil
}

func (a *App) UnregisterPluginForSharedChannels(pluginID string) error {
	rc, err := a.Srv().Store().RemoteCluster().GetByPluginID(pluginID)
	if err != nil {
		return err
	}

	if rc.DeleteAt != 0 {
		// plugin already unregistered, nothing to do
		return nil
	}

	_, appErr := a.DeleteRemoteCluster(rc.RemoteId)
	if appErr != nil {
		return appErr
	}
	return nil
}

func (a *App) AddRemoteCluster(rc *model.RemoteCluster) (*model.RemoteCluster, *model.AppError) {
	rc, err := a.Srv().Store().RemoteCluster().Save(rc)
	if err != nil {
		if sqlstore.IsUniqueConstraintError(errors.Cause(err), []string{sqlstore.RemoteClusterSiteURLUniqueIndex}) {
			return nil, model.NewAppError("AddRemoteCluster", "api.remote_cluster.save_not_unique.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
		}

		return nil, model.NewAppError("AddRemoteCluster", "api.remote_cluster.save.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
	}
	return rc, nil
}

func (a *App) PatchRemoteCluster(rcId string, patch *model.RemoteClusterPatch) (*model.RemoteCluster, *model.AppError) {
	rc, err := a.GetRemoteCluster(rcId, false)
	if err != nil {
		return nil, err
	}

	rc.Patch(patch)

	updatedRC, err := a.UpdateRemoteCluster(rc)
	if err != nil {
		return nil, err
	}

	return updatedRC, nil
}

func (a *App) UpdateRemoteCluster(rc *model.RemoteCluster) (*model.RemoteCluster, *model.AppError) {
	rc, err := a.Srv().Store().RemoteCluster().Update(rc)
	if err != nil {
		if sqlstore.IsUniqueConstraintError(errors.Cause(err), []string{sqlstore.RemoteClusterSiteURLUniqueIndex}) {
			return nil, model.NewAppError("UpdateRemoteCluster", "api.remote_cluster.update_not_unique.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
		}

		return nil, model.NewAppError("UpdateRemoteCluster", "api.remote_cluster.update.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
	}
	return rc, nil
}

func (a *App) DeleteRemoteCluster(remoteClusterId string) (bool, *model.AppError) {
	deleted, err := a.Srv().Store().RemoteCluster().Delete(remoteClusterId)
	if err != nil {
		return false, model.NewAppError("DeleteRemoteCluster", "api.remote_cluster.delete.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
	}
	return deleted, nil
}

func (a *App) GetRemoteCluster(remoteClusterId string, includeDeleted bool) (*model.RemoteCluster, *model.AppError) {
	rc, err := a.Srv().Store().RemoteCluster().Get(remoteClusterId, includeDeleted)
	if err != nil {
		switch {
		case errors.Is(err, sql.ErrNoRows):
			return nil, model.NewAppError("GetRemoteCluster", "api.remote_cluster.get.not_found", nil, "", http.StatusNotFound).Wrap(err)
		default:
			return nil, model.NewAppError("GetRemoteCluster", "api.remote_cluster.get.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
		}
	}
	return rc, nil
}

func (a *App) GetAllRemoteClusters(page, perPage int, filter model.RemoteClusterQueryFilter) ([]*model.RemoteCluster, *model.AppError) {
	list, err := a.Srv().Store().RemoteCluster().GetAll(page*perPage, perPage, filter)
	if err != nil {
		return nil, model.NewAppError("GetAllRemoteClusters", "api.remote_cluster.get.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
	}
	return list, nil
}

func (a *App) UpdateRemoteClusterTopics(remoteClusterId string, topics string) (*model.RemoteCluster, *model.AppError) {
	rc, err := a.Srv().Store().RemoteCluster().UpdateTopics(remoteClusterId, topics)
	if err != nil {
		return nil, model.NewAppError("UpdateRemoteClusterTopics", "api.remote_cluster.save.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
	}
	return rc, nil
}

func (a *App) SetRemoteClusterLastPingAt(remoteClusterId string) *model.AppError {
	err := a.Srv().Store().RemoteCluster().SetLastPingAt(remoteClusterId)
	if err != nil {
		return model.NewAppError("SetRemoteClusterLastPingAt", "api.remote_cluster.save.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
	}
	return nil
}

func (a *App) GetRemoteClusterService() (remotecluster.RemoteClusterServiceIFace, *model.AppError) {
	service := a.Srv().GetRemoteClusterService()
	if service == nil {
		return nil, model.NewAppError("GetRemoteClusterService", "api.remote_cluster.service_not_enabled.app_error", nil, "", http.StatusNotImplemented)
	}
	return service, nil
}

func (a *App) CreateRemoteClusterInvite(remoteId, siteURL, token, password string) (string, *model.AppError) {
	invite := &model.RemoteClusterInvite{
		RemoteId: remoteId,
		SiteURL:  siteURL,
		Token:    token,
		Version:  3,
	}

	if err := invite.IsValid(); err != nil {
		return "", model.NewAppError("CreateRemoteClusterInvite", "api.remote_cluster.create_invite_error", nil, "", http.StatusInternalServerError).Wrap(err)
	}

	encrypted, err := invite.Encrypt(password)
	if err != nil {
		return "", model.NewAppError("CreateRemoteClusterInvite", "api.remote_cluster.encrypt_invite_error", nil, "", http.StatusInternalServerError).Wrap(err)
	}

	return base64.URLEncoding.EncodeToString(encrypted), nil
}

func (a *App) DecryptRemoteClusterInvite(inviteCode, password string) (*model.RemoteClusterInvite, *model.AppError) {
	decoded, err := base64.URLEncoding.DecodeString(inviteCode)
	if err != nil {
		return nil, model.NewAppError("DecryptRemoteClusterInvite", "api.remote_cluster.base64_decode_error", nil, "", http.StatusBadRequest).Wrap(err)
	}

	invite := &model.RemoteClusterInvite{}
	if dErr := invite.Decrypt(decoded, password); dErr != nil {
		return nil, model.NewAppError("DecryptRemoteClusterInvite", "api.remote_cluster.invite_decrypt_error", nil, "", http.StatusBadRequest).Wrap(dErr)
	}

	return invite, nil
}