/*
 * Copyright 2018-present Open Networking Foundation

 * 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 common

import (
	"errors"
	"fmt"
	"github.com/opencord/voltha-go/common/log"
	"github.com/opencord/voltha-go/kafka"
	"github.com/opencord/voltha-protos/go/voltha"
	"strconv"
	"strings"
	"time"
)

const (
	EventTypeVersion = "0.1"
)

type (
	EventType        = voltha.EventType_EventType
	EventCategory    = voltha.EventCategory_EventCategory
	EventSubCategory = voltha.EventSubCategory_EventSubCategory
)

type EventProxy struct {
	kafkaClient kafka.Client
	eventTopic  kafka.Topic
}

func NewEventProxy(opts ...EventProxyOption) *EventProxy {
	var proxy EventProxy
	for _, option := range opts {
		option(&proxy)
	}
	return &proxy
}

type EventProxyOption func(*EventProxy)

func MsgClient(client kafka.Client) EventProxyOption {
	return func(args *EventProxy) {
		args.kafkaClient = client
	}
}

func MsgTopic(topic kafka.Topic) EventProxyOption {
	return func(args *EventProxy) {
		args.eventTopic = topic
	}
}

func (ep *EventProxy) formatId(eventName string) string {
	return fmt.Sprintf("Voltha.openolt.%s.%s", eventName, strconv.FormatInt(time.Now().UnixNano(), 10))
}

func (ep *EventProxy) getEventHeader(eventName string, category EventCategory, subCategory EventSubCategory, eventType EventType, raisedTs int64) *voltha.EventHeader {
	var header voltha.EventHeader
	if strings.Contains(eventName, "_") {
		eventName = strings.Join(strings.Split(eventName, "_")[:len(strings.Split(eventName, "_"))-2], "_")
	} else {
		eventName = "UNKNOWN_EVENT"
	}
	/* Populating event header */
	header.Id = ep.formatId(eventName)
	header.Category = category
	header.SubCategory = subCategory
	header.Type = eventType
	header.TypeVersion = EventTypeVersion
	header.RaisedTs = float32(raisedTs)
	header.ReportedTs = float32(time.Now().UnixNano())
	return &header
}

/* Send out device events*/
func (ep *EventProxy) SendDeviceEvent(deviceEvent *voltha.DeviceEvent, category EventCategory, subCategory EventSubCategory, raisedTs int64) error {
	if deviceEvent == nil {
		log.Error("Recieved empty device event")
		return errors.New("Device event nil")
	}
	var event voltha.Event
	var de voltha.Event_DeviceEvent
	de.DeviceEvent = deviceEvent
	event.Header = ep.getEventHeader(deviceEvent.DeviceEventName, category, subCategory, voltha.EventType_DEVICE_EVENT, raisedTs)
	event.EventType = &de
	if err := ep.sendEvent(&event); err != nil {
		log.Errorw("Failed to send device event to KAFKA bus", log.Fields{"device-event": deviceEvent})
		return err
	}
	log.Infow("Successfully sent device event KAFKA", log.Fields{"Id": event.Header.Id, "Category": event.Header.Category,
		"SubCategory": event.Header.SubCategory, "Type": event.Header.Type, "TypeVersion": event.Header.TypeVersion,
		"ReportedTs": event.Header.ReportedTs, "ResourceId": deviceEvent.ResourceId, "Context": deviceEvent.Context,
		"DeviceEventName": deviceEvent.DeviceEventName})

	return nil

}

/* TODO: Send out KPI events*/

func (ep *EventProxy) sendEvent(event *voltha.Event) error {
	if err := ep.kafkaClient.Send(event, &ep.eventTopic); err != nil {
		return err
	}
	log.Debugw("Sent event to kafka", log.Fields{"event": event})

	return nil
}