/*
* Copyright 2022-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 onosnbi

import (
	"context"
	"encoding/json"
	"net/http"
	"strconv"
	cntlr "voltha-go-controller/internal/pkg/controller"
	errorCodes "voltha-go-controller/internal/pkg/errorcodes"
	"voltha-go-controller/log"

	"github.com/gorilla/mux"
)

type MetersHandle struct {
}

func init() {
	// Setup this package so that it's log level can be modified at run time
	var err error
	logger, err = log.AddPackageWithDefaultParam()
	if err != nil {
		panic(err)
	}
}

// ServeHTTP to serve http request
func (mh *MetersHandle) MeterServeHTTP(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)
	meterID := vars["id"]

	logger.Infow(ctx, "Received-northbound-request ", log.Fields{"Method": r.Method, "URL": r.URL, "meterID": meterID})
	switch r.Method {
	case cGet:
		if meterID != "" {
			mh.GetMeter(context.Background(), meterID, w, r)
		} else {
			mh.GetAllMeters(context.Background(), w, r)
		}

	default:
		logger.Warnw(ctx, "Unsupported Method", log.Fields{"Method": r.Method})
		err := errorCodes.ErrOperationNotSupported
		http.Error(w, err.Error(), http.StatusBadRequest)
	}
}

func (mh *MetersHandle) GetMeter(cntx context.Context, meterID string, w http.ResponseWriter, r *http.Request) {
	meterListResp := MeterList{}
	meterListResp.Meters = []Meters{}
	mID, err := strconv.ParseUint(meterID, 10, 32)
	if err != nil {
		logger.Errorw(ctx, "Failed to parse meterID from string to uint32", log.Fields{"Meter ID": mID, "Reason": err.Error()})
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	id := uint32(mID)
	logger.Infow(ctx, "Meter Id", log.Fields{"metreId": id})
	var voltContrIntr cntlr.VoltControllerInterface
	cntrlr := cntlr.GetController()
	voltContrIntr = cntrlr
	meterInfo, err := voltContrIntr.GetMeterInfo(cntx, id)
	if err != nil {
		logger.Errorw(ctx, "Failed to get meter info from device with Meter Id", log.Fields{"Meter ID": mID, "Reason": err.Error()})
		w.WriteHeader(http.StatusNotFound)
		return
	}

	for deviceID, meter := range meterInfo {
		meterResp := mh.MeterObjectMapping(meter, deviceID)
		meterListResp.Meters = append(meterListResp.Meters, meterResp)
	}
	MeterRespJSON, err := json.Marshal(meterListResp)
	if err != nil {
		logger.Errorw(ctx, "Error occurred while marshaling meter response", log.Fields{"Meter ID": mID, "MeterListResp": meterListResp, "Error": err})
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	w.Header().Add("Content-Type", "application/json")
	_, err = w.Write(MeterRespJSON)
	if err != nil {
		logger.Errorw(ctx, "error in sending meter response", log.Fields{"Meter ID": mID, "MeterListResp": meterListResp, "Error": err})
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	logger.Debugw(ctx, "Fetch Meter Info specific to received Meter Id", log.Fields{"metreId": id, "MeterListResp": meterListResp})
}

func (mh *MetersHandle) GetAllMeters(cntx context.Context, w http.ResponseWriter, r *http.Request) {
	metersList := MeterList{}
	metersList.Meters = []Meters{}
	var voltContrIntr cntlr.VoltControllerInterface
	cntrlr := cntlr.GetController()
	voltContrIntr = cntrlr
	meterInfo, err := voltContrIntr.GetAllMeterInfo()
	if err != nil {
		logger.Errorw(ctx, "Failed to get meter info", log.Fields{"Reason": err.Error()})
		w.WriteHeader(http.StatusNotFound)
		return
	}
	for deviceID, meters := range meterInfo {
		for _, meter := range meters {
			mtr := mh.MeterObjectMapping(meter, deviceID)
			metersList.Meters = append(metersList.Meters, mtr)
		}
	}
	MeterRespJSON, err := json.Marshal(metersList)
	if err != nil {
		logger.Errorw(ctx, "Error occurred while marshaling meter response", log.Fields{"MetersList": metersList, "Error": err})
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	w.Header().Add("Content-Type", "application/json")
	_, err = w.Write(MeterRespJSON)
	if err != nil {
		logger.Errorw(ctx, "error in sending meter response", log.Fields{"MetersList": metersList, "Error": err})
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	logger.Debugw(ctx, "Fetching all Meter Info from device", log.Fields{"MetersList": metersList})
}