/*
* 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/internal/pkg/of"
	"voltha-go-controller/log"

	"github.com/gorilla/mux"
)

// FlowHandle struct to handle flow related REST calls
type FlowHandle struct {
}

// FlowHandle struct to handle flow related REST calls
type PendingFlowHandle struct {
}

type TrafficSelector struct {
}

type TrafficTreatment struct {
}

/*
type FlowEntry struct {
	TrafficSelector
	TrafficTreatment
	FlowID int
	AppID  int
	GroupID int
	Priority int
	DeviceID string
	TimeOut int
	TableID int
}*/

func (fh *FlowHandle) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	logger.Infow(ctx, "Received-northbound-request", log.Fields{"Method": r.Method, "URL": r.URL})
	switch r.Method {
	case cGet:
		fh.GetFlows(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 (pfh *PendingFlowHandle) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	logger.Infow(ctx, "Received-northbound-request", log.Fields{"Method": r.Method, "URL": r.URL})
	switch r.Method {
	case cGet:
		pfh.GetPendingFlows(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 (pfh *PendingFlowHandle) GetPendingFlows(cntx context.Context, w http.ResponseWriter, r *http.Request) {
	logger.Debug(ctx, "Received Get Pending Flows request")

	var voltContrIntr cntlr.VoltControllerInterface
	cntrlr := cntlr.GetController()
	voltContrIntr = cntrlr
	flows, err := voltContrIntr.GetAllPendingFlows()
	if err != nil {
		logger.Errorw(ctx, "Failed to get Pending flows", log.Fields{"Error": err})
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	flowResp := ConvertFlowsToFlowEntry(flows)
	FlowRespJSON, err := json.Marshal(flowResp)
	if err != nil {
		logger.Errorw(ctx, "Failed to marshal pending flow response", log.Fields{"Flows": flows, "Error": err})
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	w.Header().Add("Content-Type", "application/json")
	_, err = w.Write(FlowRespJSON)
	if err != nil {
		logger.Errorw(ctx, "Failed to write Pending Flow response", log.Fields{"Flows": flows, "Error": err})
		w.WriteHeader(http.StatusInternalServerError)
	}
}

func (fh *FlowHandle) GetFlows(cntx context.Context, w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)
	deviceID := vars["deviceId"]
	flowIDStr := vars["flowId"]
	var flowID uint64
	var parseErr error

	logger.Debugw(ctx, "Received Get Flows specific to flowID and deviceID", log.Fields{"flowId": flowIDStr, "DeviceID": deviceID})
	if len(flowIDStr) > 0 {
		flowID, parseErr = strconv.ParseUint(flowIDStr, 10, 64)
		if parseErr != nil {
			logger.Errorw(ctx, "Failed to parse flowIDStr from string to uint64", log.Fields{"flowIDStr": flowIDStr, "Reason": parseErr.Error()})
			w.WriteHeader(http.StatusInternalServerError)
			return
		}
	}

	var flowResp FlowEntry
	if len(deviceID) > 0 && len(flowIDStr) > 0 {
		flow, err := fh.getFlow(deviceID, flowID)
		if err != nil {
			logger.Errorw(ctx, "Failed to Fetch flow", log.Fields{"FlowID": flowID, "DeviceID": deviceID, "Error": err})
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}
		flowResp = ConvertFlowToFlowEntry(flow)
		// flowResp = append(flowResp, flow)
	} else {
		flows, err := fh.getAllFlows(deviceID)
		if err != nil {
			logger.Errorw(ctx, "Failed to Fetch flows", log.Fields{"DeviceID": deviceID, "Error": err})
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}
		flowResp = ConvertFlowsToFlowEntry(flows)
		// ..flowResp = append(flowResp, flows...)
	}
	FlowRespJSON, err := json.Marshal(flowResp)
	if err != nil {
		logger.Errorw(ctx, "Failed to marshal flow response", log.Fields{"FlowID": flowID, "DeviceID": deviceID, "Error": err})
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	w.Header().Add("Content-Type", "application/json")
	_, err = w.Write(FlowRespJSON)
	if err != nil {
		logger.Errorw(ctx, "Failed to write flow response", log.Fields{"FlowID": flowID, "DeviceID": deviceID, "Error": err})
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	logger.Debugw(ctx, "Request for getting Flow specific to flowID and deviceID", log.Fields{"FlowID": flowID, "DeviceID": deviceID, "flowResp": flowResp})
}

func (fh *FlowHandle) getAllFlows(deviceID string) ([]*of.VoltSubFlow, error) {
	var voltContrIntr cntlr.VoltControllerInterface
	cntrlr := cntlr.GetController()
	voltContrIntr = cntrlr
	if len(deviceID) == 0 {
		return voltContrIntr.GetAllFlows()
	}
	return voltContrIntr.GetFlows(deviceID)
}

func (fh *FlowHandle) getFlow(deviceID string, flowID uint64) (*of.VoltSubFlow, error) {
	var voltContrIntr cntlr.VoltControllerInterface
	cntrlr := cntlr.GetController()
	voltContrIntr = cntrlr
	return voltContrIntr.GetFlow(deviceID, flowID)
}