// Copyright 2017 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package apidAnalytics

import (
	"github.com/apid/apid-core"
	"github.com/apigee-labs/transicator/common"
)

type handler struct{}

func (h *handler) String() string {
	return "apigeeAnalytics"
}

func (h *handler) Handle(e apid.Event) {
	snapData, ok := e.(*common.Snapshot)
	if ok {
		processSnapshot(snapData)
	} else {
		changeSet, ok := e.(*common.ChangeList)
		if ok {
			processChange(changeSet)
		} else {
			log.Errorf("Received Invalid event. Ignoring. %v", e)
		}
	}
	return
}

func processSnapshot(snapshot *common.Snapshot) {
	log.Debugf("Snapshot received. Switching to"+
		" DB version: %s", snapshot.SnapshotInfo)

	db, err := data.DBVersion(snapshot.SnapshotInfo)
	if err != nil {
		log.Panicf("Unable to access database: %v", err)
	}
	setDB(db)

	if config.GetBool(useCaching) {
		createTenantCache()
		log.Debug("Created a local cache" +
			" for datasope information")
		createOrgEnvCache()
		log.Debug("Created a local cache for org~env Information")
	} else {
		log.Info("Will not be caching any developer or tenant info " +
			"and make a DB call for every analytics msg")
	}
	return
}

func processChange(changes *common.ChangeList) {
	if config.GetBool(useCaching) {
		log.Debugf("apigeeSyncEvent: %d changes", len(changes.Changes))
		var rows []common.Row

		for _, payload := range changes.Changes {
			rows = nil
			switch payload.Table {
			case "edgex.data_scope":
				switch payload.Operation {
				case common.Insert, common.Update:
					rows = append(rows, payload.NewRow)
					// Lock before writing to the
					// map as it has multiple readers
					tenantCachelock.Lock()
					defer tenantCachelock.Unlock()

					orgEnvCacheLock.Lock()
					defer orgEnvCacheLock.Unlock()

					for _, ele := range rows {
						var scopeuuid, tenantid string
						var org, env string
						ele.Get("id", &scopeuuid)
						ele.Get("scope", &tenantid)
						ele.Get("org", &org)
						ele.Get("env", &env)
						if scopeuuid != "" {
							tenantCache[scopeuuid] = tenant{
								Org: org,
								Env: env}
							log.Debugf("Refreshed local "+
								"tenantCache. Added "+
								"scope: "+"%s", scopeuuid)
						}

						orgEnv := getKeyForOrgEnvCache(org, env)
						if orgEnv != "" {
							orgEnvCache[orgEnv] = true
							log.Debugf("Refreshed local "+
								"orgEnvCache. Added "+
								"orgEnv: "+"%s", orgEnv)
						}
					}
				case common.Delete:
					rows = append(rows, payload.OldRow)
					// Lock before writing to the map
					// as it has multiple readers
					tenantCachelock.Lock()
					defer tenantCachelock.Unlock()

					orgEnvCacheLock.Lock()
					defer orgEnvCacheLock.Unlock()
					for _, ele := range rows {
						var scopeuuid, org, env string
						ele.Get("id", &scopeuuid)
						ele.Get("org", &org)
						ele.Get("env", &env)
						if scopeuuid != "" {
							delete(tenantCache, scopeuuid)
							log.Debugf("Refreshed local"+
								" tenantCache. Deleted"+
								" scope: %s", scopeuuid)
						}
						orgEnv := getKeyForOrgEnvCache(org, env)
						if orgEnv != "" {
							delete(orgEnvCache, orgEnv)
							log.Debugf("Refreshed local"+
								" orgEnvCache. Deleted"+
								" org~env: %s", orgEnv)
						}
					}
				}
			}
		}

	}
}