/*
 * Copyright (c) 2024  The AdvantEDGE Authors
 *
 * 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 iotmgr

import (
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"reflect"
	"strconv"
	"strings"
	"sync"
	"time"

	log "github.com/InterDigitalInc/AdvantEDGE/go-packages/meep-logger"

	uuid "github.com/google/uuid"
	"github.com/gorilla/mux"
)

// IOT Manager
type IotMgr struct {
	name      string
	namespace string
	mutex     sync.Mutex
}

type IotPlatformInfo struct {
	IotPlatformId               string
	UserTransportInfo           []MbTransportInfo
	CustomServicesTransportInfo []TransportInfo
	Enabled                     bool
}

type MbTransportInfo struct {
	Id               string
	Name             string
	Description      string
	Type_            *string
	Protocol         string
	Version          string
	Endpoint         *EndPointInfo
	Security         *SecurityInfo
	ImplSpecificInfo *ImplSpecificInfo
}

type TransportInfo struct {
	Id               string
	Name             string
	Description      string
	Type_            *string
	Protocol         string
	Version          string
	Endpoint         *EndPointInfo
	Security         *SecurityInfo
	ImplSpecificInfo string
}

type EndPointInfo struct {
	Uris        []string
	Fqdn        []string
	Addresses   []Addresses
	Alternative string
}

type Addresses struct {
	Host string
	Port int32
}

type SecurityInfo struct {
	OAuth2Info *OAuth2Info
	Extensions string
}

type OAuth2Info struct {
	GrantTypes    []string
	TokenEndpoint string
}

type ImplSpecificInfo struct {
	EventTopics    []string
	UplinkTopics   []string
	DownlinkTopics []string
}

// ETSI GS MEC 046 V3.1.1 (2024-04) Clause 6.2.1 Type: SensorDiscoveryInfo
type SensorCharacteristic struct {
	CharacteristicName          string
	CharacteristicValue         string
	CharacteristicUnitOfMeasure *string
}

type DeviceInfo struct {
	DeviceAuthenticationInfo string
	//DeviceMetadata []KeyValuePair
	Gpsi     string
	Pei      string
	Supi     string
	Msisdn   string
	Imei     string
	Imsi     string
	Iccid    string
	DeviceId string
	//RequestedMecTrafficRule []TrafficRuleDescriptor
	RequestedIotPlatformId   string
	RequestedUserTransportId string
	//DeviceSpecificMessageFormats *DeviceSpecificMessageFormats
	//DownlinkInfo *DownlinkInfo
	ClientCertificate        string
	Enabled                  bool
	SensorIdentifier         string
	SensorStatusType         string
	SensorPropertyList       []string
	SensorCharacteristicList []SensorCharacteristic
}

var registeredIotPlatformsMap = map[string]IotPlatformInfo{} // List of discovered IOT Plateform
var devicesMap = map[string]DeviceInfo{}                     // Map device by deviceId
var devicesPerPlatformMap = map[string][]string{}            // Map deviceIds per platform

// Enable profiling
const profiling = false

var profilingTimers map[string]time.Time

const (
	headerAccept      = "application/json"
	headerContentType = "application/json"
)

// Profiling init
func init() {
	if profiling {
		profilingTimers = make(map[string]time.Time)
	}
}

// NewIotMgr - Creates and initializes a new IOT Traffic Manager
func NewIotMgr(name string, namespace string) (tm *IotMgr, err error) {
	if name == "" {
		err = errors.New("Missing connector name")
		return nil, err
	}

	// Create new Traffic Manager
	tm = new(IotMgr)
	tm.name = name
	if namespace != "" {
		tm.namespace = namespace
	} else {
		tm.namespace = "default"
	}

	return tm, nil
}

// DeleteIotMgr -
func (tm *IotMgr) DeleteIotMgr() (err error) {

	return nil
}

func (tm *IotMgr) RegisterIotPlatformInfo(iotPlatformInfo IotPlatformInfo) (err error) {
	if profiling {
		profilingTimers["RegisterIotPlatformInfo"] = time.Now()
	}

	log.Info(">>> RegisterIotPlatformInfo: iotPlatformId: ", iotPlatformInfo)
	if iotPlatformInfo.Enabled {
		registeredIotPlatformsMap[iotPlatformInfo.IotPlatformId] = iotPlatformInfo
	} // else, Skip disabled platform

	if profiling {
		now := time.Now()
		log.Debug("RegisterIotPlatformInfo: ", now.Sub(profilingTimers["RegisterIotPlatformInfo"]))
	}
	return nil
}

func (tm *IotMgr) DeregisterIotPlatformInfo(iotPlatformId string) (err error) {
	if profiling {
		profilingTimers["DeregisterIotPlatformInfo"] = time.Now()
	}

	log.Info(">>> DeregisterIotPlatformInfo: iotPlatformId: ", iotPlatformId)
	// Remove the list of the devices for this IoT platform
	if val, ok := devicesPerPlatformMap[iotPlatformId]; ok {
		// Free resources from devicesMap map
		for _, dev := range val {
			delete(devicesMap, dev)
		} // End of 'for' statement
		delete(devicesPerPlatformMap, iotPlatformId)
	}
	if _, ok := registeredIotPlatformsMap[iotPlatformId]; ok {
		delete(registeredIotPlatformsMap, iotPlatformId)
	}

	if profiling {
		now := time.Now()
		log.Debug("DeregisterIotPlatformInfo: ", now.Sub(profilingTimers["DeregisterIotPlatformInfo"]))
	}
	return nil
}

func (tm *IotMgr) GetDevices() (devices []DeviceInfo, err error) {
	if profiling {
		profilingTimers["GetDevices"] = time.Now()
	}

	log.Info(">>> GetDevices")

	devices = make([]DeviceInfo, 0)
	if len(registeredIotPlatformsMap) == 0 {
		return devices, nil
	}

	// Refresh the list of devices
	for _, iotPlatform := range registeredIotPlatformsMap {
		log.Info("GetDevices: processing: ", iotPlatform.IotPlatformId)
		err := populateDevices(iotPlatform)
		if err != nil {
			log.Error("GetDevices: ", err)
			continue
		}
		for _, v := range devicesPerPlatformMap[iotPlatform.IotPlatformId] {
			log.Info("GetDevices: adding device: ", v)
			devices = append(devices, devicesMap[v])
		}
	} // End of 'for' statement
	log.Info("GetDevices: devices: ", devices)

	if profiling {
		now := time.Now()
		log.Debug("GetDevices: ", now.Sub(profilingTimers["GetDevices"]))
	}
	return devices, nil
}

func (tm *IotMgr) GetDevice(deviceId string) (device DeviceInfo, err error) {
	if profiling {
		profilingTimers["GetDevice"] = time.Now()
	}

	log.Info(">>> GetDevice: deviceId: ", deviceId)

	if val, ok := devicesMap[deviceId]; !ok {
		err = errors.New("Wrong Device identifier")
		return device, err
	} else {
		log.Info(" GetDevice: device: ", val)
		device = val
	}

	if profiling {
		now := time.Now()
		log.Debug("GetDevice: ", now.Sub(profilingTimers["GetDevice"]))
	}
	return device, nil
}

/*
 * func PopulateDevices IoT devices for the specified Iot platform
 * @param {string} iotPlatformId contains the IoT platform identifier
 * @return {struct} nil on success, error otherwise
 */
func populateDevices(iotPlatformInfo IotPlatformInfo) error {
	if profiling {
		profilingTimers["populateDevices"] = time.Now()
	}

	log.Info(">>> populateDevices: iotPlatformId=", iotPlatformInfo.IotPlatformId)

	// 1. Get the list of the AE
	// Build the URL
	t := registeredIotPlatformsMap[iotPlatformInfo.IotPlatformId].CustomServicesTransportInfo[0]
	log.Info("populateDevices: t.Endpoint.Addresses[0]=", t.Endpoint.Addresses[0])
	url := "http://" + t.Endpoint.Addresses[0].Host + ":" + strconv.Itoa(int(t.Endpoint.Addresses[0].Port)) + "/" + t.Name
	log.Info("populateDevices: url=", url)
	// Build the headers
	var headers = http.Header{}
	headers["Accept"] = []string{headerAccept}
	headers["ContentType"] = []string{headerContentType}
	headers["X-M2M-Origin"] = []string{"CAdmin"}
	headers["X-M2M-RI"] = []string{uuid.New().String()}
	headers["X-M2M-RVI"] = []string{t.Version}
	// Build the queries
	queries := map[string]string{}
	queries["fu"] = "1" // Filter usage
	queries["ty"] = "4" // Filter on oneM2M CIN for device
	// Send the request
	response, err := sendRequest("GET", url, headers, nil, nil, queries, 200)
	if err != nil {
		log.Error("populateDevices: ", err.Error())
		return err
	}
	log.Debug("populateDevices: response: ", string(response))

	var oneM2M_uril map[string][]string
	err = json.Unmarshal(response, &oneM2M_uril)
	if err != nil {
		log.Error("populateDevices: ", err.Error())
		return err
	}
	log.Debug("populateDevices: oneM2M_uril: ", len(oneM2M_uril))
	log.Debug(oneM2M_uril)
	if _, ok := oneM2M_uril["m2m:uril"]; !ok {
		err := errors.New("populateDevices: Key not found: m2m:uril")
		log.Error(err.Error())
		return err
	}
	// Loop for each CIN and build the device list
	for _, v := range oneM2M_uril["m2m:uril"] {
		log.Info("populateDevices: Processing key: ", v)

		url := "http://" + t.Endpoint.Addresses[0].Host + ":" + strconv.Itoa(int(t.Endpoint.Addresses[0].Port)) + "/" + v
		log.Info("populateDevices: url=", url)
		// Build the headers
		var headers = http.Header{}
		headers["Accept"] = []string{headerAccept}
		headers["ContentType"] = []string{headerContentType}
		headers["X-M2M-Origin"] = []string{"CAdmin"}
		headers["X-M2M-RI"] = []string{uuid.New().String()}
		headers["X-M2M-RVI"] = []string{t.Version}
		// Build the queries
		queries := map[string]string{}
		queries["fu"] = "2" // Filter usage
		// Send the request
		response, err := sendRequest("GET", url, headers, nil, nil, queries, 200)
		if err != nil {
			log.Error("populateDevices: ", err.Error())
			return err
		}
		log.Debug("populateDevices: response: ", string(response))
		var oneM2M_cin map[string]map[string]interface{}
		err = json.Unmarshal(response, &oneM2M_cin)
		if err != nil {
			log.Error("populateDevices: ", err.Error())
			continue
		}
		//log.Debug("populateDevices: type(oneM2M_cin): ", reflect.TypeOf(oneM2M_cin))
		//log.Debug("populateDevices: len(oneM2M_cin): ", len(oneM2M_cin))
		//log.Debug("populateDevices: oneM2M_cin: ", oneM2M_cin)
		for _, m := range oneM2M_cin {
			//log.Debug("==> ", i, " value is ", m)
			var device = DeviceInfo{}
			device.RequestedIotPlatformId = iotPlatformInfo.IotPlatformId
			device.RequestedUserTransportId = registeredIotPlatformsMap[iotPlatformInfo.IotPlatformId].UserTransportInfo[0].Id
			device.Enabled = true

			// m is a map[string]interface.
			// loop over keys and values in the map.
			for k, v := range m {
				log.Debug(k, " value is ", v)
				log.Debug("populateDevices: type(v): ", reflect.TypeOf(v))
				if k == "rn" {
					if item, ok := v.(string); ok {
						device.DeviceId = item
					} else {
						log.Error("populateDevices: Failed to process ", k)
					}
				} else if k == "ri" {
					if item, ok := v.(string); ok {
						device.SensorIdentifier = item
					} else {
						log.Error("populateDevices: Failed to process ", k)
					}
				} else if k == "ty" {
					if item, ok := v.(float64); ok {
						device.SensorStatusType = strconv.FormatFloat(item, 'f', -1, 64)
					} else {
						log.Error("populateDevices: Failed to process ", k)
					}
				} else { // default: if k == "lt" || k == "et" || k == "ct" || k == "st" || k == "pi" || k == "lbl" {
					if item, ok := v.(string); ok {
						device.SensorCharacteristicList = append(
							device.SensorCharacteristicList,
							SensorCharacteristic{
								CharacteristicName:          k,
								CharacteristicValue:         string(item),
								CharacteristicUnitOfMeasure: nil,
							})
					} else if item, ok := v.(float64); ok {
						device.SensorCharacteristicList = append(
							device.SensorCharacteristicList,
							SensorCharacteristic{
								CharacteristicName:          k,
								CharacteristicValue:         strconv.FormatFloat(item, 'f', -1, 64),
								CharacteristicUnitOfMeasure: nil,
							})
					} else if item, ok := v.([]string); ok {
						device.SensorCharacteristicList = append(
							device.SensorCharacteristicList,
							SensorCharacteristic{
								CharacteristicName:          k,
								CharacteristicValue:         strings.Join(item, ","),
								CharacteristicUnitOfMeasure: nil,
							})
					} else {
						log.Error("populateDevices: Failed to process ", k)
					}
				}
			} // End of 'for' loop
			log.Info("populateDevices: device: ", device)
			devicesMap[device.DeviceId] = device
			devicesPerPlatformMap[device.RequestedIotPlatformId] = append(devicesPerPlatformMap[device.RequestedIotPlatformId], device.DeviceId)
		} // End of 'for' loop

	} // End of 'for' statement
	log.Info("populateDevices: devicesMap: ", devicesMap)
	log.Info("populateDevices: devicesPerPlatformMap: ", devicesPerPlatformMap)

	if profiling {
		now := time.Now()
		log.Debug("populateDevices: ", now.Sub(profilingTimers["populateDevices"]))
	}
	return nil
}

func sendRequest(method string, url string, headers http.Header, body io.Reader, vars map[string]string, query map[string]string, code int) ([]byte, error) {
	log.Debug(">>> sendRequest: url: ", url)
	log.Debug(">>> sendRequest: headers: ", headers)

	req, err := http.NewRequest(method, url, body)
	if err != nil || req == nil {
		return nil, err
	}
	if vars != nil {
		req = mux.SetURLVars(req, vars)
	}
	if query != nil {
		q := req.URL.Query()
		for k, v := range query {
			q.Add(k, v)
		}
		req.URL.RawQuery = q.Encode()
	}
	req.Header = headers
	req.Close = true

	rr, err := http.DefaultClient.Do(req)
	if err != nil {
		return nil, err
	}

	// Check the status code is what we expect.
	if status := rr.StatusCode; status != code {
		s := fmt.Sprintf("Wrong status code - got %v want %v", status, code)
		return nil, errors.New(s)
	}
	responseData, err := ioutil.ReadAll(rr.Body)
	if err != nil {
		return nil, err
	}

	return responseData, nil
}