package controller

import (
	"context"
	"encoding/base64"
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"strings"
	"time"
	"os"
	"github.com/gorilla/mux"
	"github.com/gravitl/netmaker/config"
	"github.com/gravitl/netmaker/functions"
	"github.com/gravitl/netmaker/models"
	"github.com/gravitl/netmaker/mongoconn"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/mongo/options"
	"gopkg.in/go-playground/validator.v9"
)

func networkHandlers(r *mux.Router) {
	r.HandleFunc("/api/networks", securityCheck(http.HandlerFunc(getNetworks))).Methods("GET")
	r.HandleFunc("/api/networks", securityCheck(http.HandlerFunc(createNetwork))).Methods("POST")
	r.HandleFunc("/api/networks/{networkname}", securityCheck(http.HandlerFunc(getNetwork))).Methods("GET")
	r.HandleFunc("/api/networks/{networkname}", securityCheck(http.HandlerFunc(updateNetwork))).Methods("PUT")
	r.HandleFunc("/api/networks/{networkname}", securityCheck(http.HandlerFunc(deleteNetwork))).Methods("DELETE")
	r.HandleFunc("/api/networks/{networkname}/keyupdate", securityCheck(http.HandlerFunc(keyUpdate))).Methods("POST")
	r.HandleFunc("/api/networks/{networkname}/keys", securityCheck(http.HandlerFunc(createAccessKey))).Methods("POST")
	r.HandleFunc("/api/networks/{networkname}/keys", securityCheck(http.HandlerFunc(getAccessKeys))).Methods("GET")
	r.HandleFunc("/api/networks/{networkname}/keys/{name}", securityCheck(http.HandlerFunc(deleteAccessKey))).Methods("DELETE")
}

//Security check is middleware for every function and just checks to make sure that its the master calling
//Only admin should have access to all these network-level actions
//or maybe some Users once implemented
func securityCheck(next http.Handler) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		var errorResponse = models.ErrorResponse{
			Code: http.StatusInternalServerError, Message: "W1R3: It's not you it's me.",
		}

		var params = mux.Vars(r)
		hasnetwork := params["networkname"] != ""
		networkexists, err := functions.NetworkExists(params["networkname"])
		if err != nil {
			returnErrorResponse(w, r, formatError(err, "internal"))
			return
		} else if hasnetwork && !networkexists {
			errorResponse = models.ErrorResponse{
				Code: http.StatusNotFound, Message: "W1R3: This network does not exist.",
			}
			returnErrorResponse(w, r, errorResponse)
			return
		} else {

			bearerToken := r.Header.Get("Authorization")

			var hasBearer = true
			var tokenSplit = strings.Split(bearerToken, " ")
			var authToken = ""

			if len(tokenSplit) < 2 {
				hasBearer = false
			} else {
				authToken = tokenSplit[1]
			}
			//all endpoints here require master so not as complicated
			//still might not be a good  way of doing this
			if !hasBearer || !authenticateMaster(authToken) {
				errorResponse = models.ErrorResponse{
					Code: http.StatusUnauthorized, Message: "W1R3: You are unauthorized to access this endpoint.",
				}
				returnErrorResponse(w, r, errorResponse)
				return
			} else {
				next.ServeHTTP(w, r)
			}
		}
	}
}

//Consider a more secure way of setting master key
func authenticateMaster(tokenString string) bool {
	if tokenString == config.Config.Server.MasterKey  || (tokenString == os.Getenv("MASTER_KEY") && tokenString != "") {
		return true
	}
	return false
}

//simple get all networks function
func getNetworks(w http.ResponseWriter, r *http.Request) {

	networks, err := functions.ListNetworks()

	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	} else {
		w.WriteHeader(http.StatusOK)
		json.NewEncoder(w).Encode(networks)
		return
	}
}

func validateNetworkUpdate(network models.Network) error {

	v := validator.New()

	_ = v.RegisterValidation("addressrange_valid", func(fl validator.FieldLevel) bool {
		isvalid := fl.Field().String() == "" || functions.IsIpCIDR(fl.Field().String())
		return isvalid
	})
        _ = v.RegisterValidation("addressrange6_valid", func(fl validator.FieldLevel) bool {
                isvalid := fl.Field().String() == "" || functions.IsIpCIDR(fl.Field().String())
                return isvalid
        })

	_ = v.RegisterValidation("localrange_valid", func(fl validator.FieldLevel) bool {
		isvalid := fl.Field().String() == "" || functions.IsIpCIDR(fl.Field().String())
		return isvalid
	})

	_ = v.RegisterValidation("netid_valid", func(fl validator.FieldLevel) bool {
		return true
	})

	_ = v.RegisterValidation("displayname_unique", func(fl validator.FieldLevel) bool {
		return true
	})

	err := v.Struct(network)

	if err != nil {
		for _, e := range err.(validator.ValidationErrors) {
			fmt.Println(e)
		}
	}
	return err
}

func validateNetworkCreate(network models.Network) error {

	v := validator.New()

	_ = v.RegisterValidation("addressrange_valid", func(fl validator.FieldLevel) bool {
		isvalid := functions.IsIpCIDR(fl.Field().String())
		return isvalid
	})
        _ = v.RegisterValidation("addressrange6_valid", func(fl validator.FieldLevel) bool {
		isvalid := true
		if *network.IsDualStack {
			isvalid = functions.IsIpCIDR(fl.Field().String())
		}
		return isvalid
        })


	_ = v.RegisterValidation("localrange_valid", func(fl validator.FieldLevel) bool {
		isvalid := fl.Field().String() == "" || functions.IsIpCIDR(fl.Field().String())
		return isvalid
	})

	_ = v.RegisterValidation("netid_valid", func(fl validator.FieldLevel) bool {
		isFieldUnique, _ := functions.IsNetworkNameUnique(fl.Field().String())
		inCharSet := functions.NameInNetworkCharSet(fl.Field().String())
		return isFieldUnique && inCharSet
	})

	_ = v.RegisterValidation("displayname_unique", func(fl validator.FieldLevel) bool {
		isFieldUnique, _ := functions.IsNetworkDisplayNameUnique(fl.Field().String())
		return isFieldUnique
	})

	err := v.Struct(network)

	if err != nil {
		for _, e := range err.(validator.ValidationErrors) {
			fmt.Println(e)
		}
	}
	return err
}

//Simple get network function
func getNetwork(w http.ResponseWriter, r *http.Request) {

	// set header.
	w.Header().Set("Content-Type", "application/json")

	var params = mux.Vars(r)

	var network models.Network

	collection := mongoconn.Client.Database("netmaker").Collection("networks")

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)

	filter := bson.M{"netid": params["networkname"]}
	err := collection.FindOne(ctx, filter, options.FindOne().SetProjection(bson.M{"_id": 0})).Decode(&network)

	defer cancel()

	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(network)
}

func keyUpdate(w http.ResponseWriter, r *http.Request) {

	w.Header().Set("Content-Type", "application/json")

	var params = mux.Vars(r)

	var network models.Network

	network, err := functions.GetParentNetwork(params["networkname"])
	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}

	network.KeyUpdateTimeStamp = time.Now().Unix()

	collection := mongoconn.Client.Database("netmaker").Collection("networks")

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)

        filter := bson.M{"netid": params["networkname"]}
        // prepare update model.
        update := bson.D{
                {"$set", bson.D{
                        {"addressrange", network.AddressRange},
                        {"addressrange6", network.AddressRange6},
                        {"displayname", network.DisplayName},
                        {"defaultlistenport", network.DefaultListenPort},
                        {"defaultpostup", network.DefaultPostUp},
                        {"defaultpostdown", network.DefaultPostDown},
			{"defaultkeepalive", network.DefaultKeepalive},
			{"keyupdatetimestamp", network.KeyUpdateTimeStamp},
			{"defaultsaveconfig", network.DefaultSaveConfig},
			{"defaultinterface", network.DefaultInterface},
			{"nodeslastmodified", network.NodesLastModified},
			{"networklastmodified", network.NetworkLastModified},
			{"allowmanualsignup", network.AllowManualSignUp},
			{"checkininterval", network.DefaultCheckInInterval},
		        }},
	      }

	err = collection.FindOneAndUpdate(ctx, filter, update).Decode(&network)

	defer cancel()

	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}

	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(network)
}

//Update a network
func AlertNetwork(netid string) error {

	collection := mongoconn.Client.Database("netmaker").Collection("networks")
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	filter := bson.M{"netid": netid}

	var network models.Network

	network, err := functions.GetParentNetwork(netid)
	if err != nil {
		return err
	}
	updatetime := time.Now().Unix()
	update := bson.D{
		{"$set", bson.D{
			{"nodeslastmodified", updatetime},
			{"networklastmodified", updatetime},
		}},
	}

	err = collection.FindOneAndUpdate(ctx, filter, update).Decode(&network)
	defer cancel()

	return err
}

//Update a network
func updateNetwork(w http.ResponseWriter, r *http.Request) {

	w.Header().Set("Content-Type", "application/json")

	var params = mux.Vars(r)

	var network models.Network

	network, err := functions.GetParentNetwork(params["networkname"])
	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}

	var networkChange models.Network

	haschange := false
	hasrangeupdate := false
	haslocalrangeupdate := false

	_ = json.NewDecoder(r.Body).Decode(&networkChange)

	if networkChange.AddressRange == "" {
		networkChange.AddressRange = network.AddressRange
	}
        if networkChange.AddressRange6 == "" {
                networkChange.AddressRange6 = network.AddressRange6
        }
	if networkChange.NetID == "" {
		networkChange.NetID = network.NetID
	}

	err = validateNetworkUpdate(networkChange)
	if err != nil {
		returnErrorResponse(w, r, formatError(err, "badrequest"))
		return
	}

	//NOTE: Network.NetID is intentionally NOT editable. It acts as a static ID for the network.
	//DisplayName can be changed instead, which is what shows on the front end
	if networkChange.NetID != network.NetID {
		returnErrorResponse(w, r, formatError(errors.New("NetID is not editable"), "badrequest"))
		return
	}
	//MRK:  I think this code block is redundant.  valdiateNetworkUpdate(networkChange) covers this
	if networkChange.AddressRange != "" {

		network.AddressRange = networkChange.AddressRange

		var isAddressOK bool = functions.IsIpCIDR(networkChange.AddressRange)
		if !isAddressOK {
			err := errors.New("Invalid Range of " + networkChange.AddressRange + " for addresses.")
			returnErrorResponse(w, r, formatError(err, "internal"))
			return
		}
		haschange = true
		hasrangeupdate = true

	}
	if networkChange.LocalRange != "" {
		network.LocalRange = networkChange.LocalRange

		var isAddressOK bool = functions.IsIpCIDR(networkChange.LocalRange)
		if !isAddressOK {
			err := errors.New("Invalid Range of " + networkChange.LocalRange + " for internal addresses.")
			returnErrorResponse(w, r, formatError(err, "internal"))
			return
		}
		haschange = true
		haslocalrangeupdate = true
	}
	if networkChange.IsLocal != nil {
		network.IsLocal = networkChange.IsLocal
	}
        if networkChange.IsDualStack != nil {
                network.IsDualStack = networkChange.IsDualStack
        }
	if networkChange.DefaultListenPort != 0 {
		network.DefaultListenPort = networkChange.DefaultListenPort
		haschange = true
	}
	if networkChange.DefaultPostDown != "" {
		network.DefaultPostDown = networkChange.DefaultPostDown
		haschange = true
	}
	if networkChange.DefaultInterface != "" {
		network.DefaultInterface = networkChange.DefaultInterface
		haschange = true
	}
	if networkChange.DefaultPostUp != "" {
		network.DefaultPostUp = networkChange.DefaultPostUp
		haschange = true
	}
	if networkChange.DefaultKeepalive != 0 {
		network.DefaultKeepalive = networkChange.DefaultKeepalive
		haschange = true
	}
	if networkChange.DisplayName != "" {
		network.DisplayName = networkChange.DisplayName
		haschange = true
	}
	if networkChange.DefaultCheckInInterval != 0 {
		network.DefaultCheckInInterval = networkChange.DefaultCheckInInterval
		haschange = true
	}
	if networkChange.AllowManualSignUp != nil {
		network.AllowManualSignUp = networkChange.AllowManualSignUp
		haschange = true
	}

	collection := mongoconn.Client.Database("netmaker").Collection("networks")
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	filter := bson.M{"netid": params["networkname"]}

	if haschange {
		network.SetNetworkLastModified()
	}
        // prepare update model.
        update := bson.D{
                {"$set", bson.D{
                        {"addressrange", network.AddressRange},
                        {"addressrange6", network.AddressRange6},
                        {"displayname", network.DisplayName},
                        {"defaultlistenport", network.DefaultListenPort},
                        {"defaultpostup", network.DefaultPostUp},
                        {"defaultpostdown", network.DefaultPostDown},
                        {"defaultkeepalive", network.DefaultKeepalive},
                        {"defaultsaveconfig", network.DefaultSaveConfig},
                        {"defaultinterface", network.DefaultInterface},
                        {"nodeslastmodified", network.NodesLastModified},
                        {"networklastmodified", network.NetworkLastModified},
                        {"allowmanualsignup", network.AllowManualSignUp},
                        {"localrange", network.LocalRange},
                        {"islocal", network.IsLocal},
                        {"isdualstack", network.IsDualStack},
                        {"checkininterval", network.DefaultCheckInInterval},
		              }},
	}

	err = collection.FindOneAndUpdate(ctx, filter, update).Decode(&network)
	defer cancel()

	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}

	//Cycles through nodes and gives them new IP's based on the new range
	//Pretty cool, but also pretty inefficient currently
	if hasrangeupdate {
		err = functions.UpdateNetworkNodeAddresses(params["networkname"])
		if err != nil {
			returnErrorResponse(w, r, formatError(err, "internal"))
			return
		}
	}
	if haslocalrangeupdate {
		err = functions.UpdateNetworkPrivateAddresses(params["networkname"])
		if err != nil {
			returnErrorResponse(w, r, formatError(err, "internal"))
			return
		}
	}
	returnnetwork, err := functions.GetParentNetwork(network.NetID)
	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}

	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(returnnetwork)
}

//Delete a network
//Will stop you if  there's any nodes associated
func deleteNetwork(w http.ResponseWriter, r *http.Request) {
	// Set header
	w.Header().Set("Content-Type", "application/json")

	var params = mux.Vars(r)

	nodecount, err := functions.GetNetworkNodeNumber(params["networkname"])
	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	} else if nodecount > 0 {
		errorResponse := models.ErrorResponse{
			Code: http.StatusForbidden, Message: "W1R3: Node check failed. All nodes must be deleted before deleting network.",
		}
		returnErrorResponse(w, r, errorResponse)
		return
	}

	collection := mongoconn.Client.Database("netmaker").Collection("networks")

	filter := bson.M{"netid": params["networkname"]}

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)

	deleteResult, err := collection.DeleteOne(ctx, filter)

	defer cancel()

	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}

	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(deleteResult)
}

//Create a network
//Pretty simple
func createNetwork(w http.ResponseWriter, r *http.Request) {

	w.Header().Set("Content-Type", "application/json")

	var network models.Network

	// we decode our body request params
	err := json.NewDecoder(r.Body).Decode(&network)
	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}

	//TODO: Not really doing good validation here. Same as createNode, updateNode, and updateNetwork
	//Need to implement some better validation across the board

	if network.IsLocal == nil {
		falsevar := false
		network.IsLocal = &falsevar
	}
        if network.IsDualStack == nil {
                falsevar := false
                network.IsDualStack = &falsevar
        }

	err = validateNetworkCreate(network)
	if err != nil {
		returnErrorResponse(w, r, formatError(err, "badrequest"))
		return
	}
	network.SetDefaults()
	network.SetNodesLastModified()
	network.SetNetworkLastModified()
	network.KeyUpdateTimeStamp = time.Now().Unix()

	collection := mongoconn.Client.Database("netmaker").Collection("networks")
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)

	// insert our network into the network table
	result, err := collection.InsertOne(ctx, network)

	defer cancel()

	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(result)
}

// BEGIN KEY MANAGEMENT SECTION

//TODO: Very little error handling
//accesskey is created as a json string inside the Network collection item in mongo
func createAccessKey(w http.ResponseWriter, r *http.Request) {

	w.Header().Set("Content-Type", "application/json")

	var params = mux.Vars(r)

	var network models.Network
	var accesskey models.AccessKey

	//start here
	network, err := functions.GetParentNetwork(params["networkname"])
	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}

	err = json.NewDecoder(r.Body).Decode(&accesskey)
	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}

	if accesskey.Name == "" {
		accesskey.Name = functions.GenKeyName()
	}
	if accesskey.Value == "" {
		accesskey.Value = functions.GenKey()
	}

	if accesskey.Uses == 0 {
		accesskey.Uses = 1
	}
	_, gconf, err := functions.GetGlobalConfig()
	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}

	privAddr := ""
	if *network.IsLocal {
		privAddr = network.LocalRange
	}

	netID := params["networkname"]
	address := gconf.ServerGRPC + gconf.PortGRPC

	accessstringdec := address + "|" + netID + "|" + accesskey.Value + "|" + privAddr
	accesskey.AccessString = base64.StdEncoding.EncodeToString([]byte(accessstringdec))

	network.AccessKeys = append(network.AccessKeys, accesskey)

	collection := mongoconn.Client.Database("netmaker").Collection("networks")

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)

	// Create filter
	filter := bson.M{"netid": params["networkname"]}

	// Read update model from body request
	fmt.Println("Adding key to " + network.NetID)

	// prepare update model.
	update := bson.D{
		{"$set", bson.D{
			{"accesskeys", network.AccessKeys},
		}},
	}

	err = collection.FindOneAndUpdate(ctx, filter, update).Decode(&network)

	defer cancel()

	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(accesskey)
	//w.Write([]byte(accesskey.AccessString))
}

//pretty simple get
func getAccessKeys(w http.ResponseWriter, r *http.Request) {

	// set header.
	w.Header().Set("Content-Type", "application/json")

	var params = mux.Vars(r)

	var network models.Network
	//var keys []models.DisplayKey
	var keys []models.AccessKey
	collection := mongoconn.Client.Database("netmaker").Collection("networks")

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)

	filter := bson.M{"netid": params["networkname"]}
	err := collection.FindOne(ctx, filter, options.FindOne().SetProjection(bson.M{"_id": 0})).Decode(&network)

	defer cancel()

	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}
	keydata, err := json.Marshal(network.AccessKeys)

	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}

	json.Unmarshal(keydata, &keys)

	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(keys)
}

//delete key. Has to do a little funky logic since it's not a collection item
func deleteAccessKey(w http.ResponseWriter, r *http.Request) {

	w.Header().Set("Content-Type", "application/json")

	var params = mux.Vars(r)

	var network models.Network
	keyname := params["name"]

	//start here
	network, err := functions.GetParentNetwork(params["networkname"])
	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}
	//basically, turn the list of access keys into the list of access keys before and after the item
	//have not done any error handling for if there's like...1 item. I think it works? need to test.
	found := false
	for i := len(network.AccessKeys) - 1; i >= 0; i-- {

		currentkey := network.AccessKeys[i]
		if currentkey.Name == keyname {
			network.AccessKeys = append(network.AccessKeys[:i],
				network.AccessKeys[i+1:]...)
			found = true
		}
	}
	if !found {
		err = errors.New("key " + keyname + " does not exist")
		returnErrorResponse(w, r, formatError(err, "badrequest"))
		return
	}

	collection := mongoconn.Client.Database("netmaker").Collection("networks")

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)

	// Create filter
	filter := bson.M{"netid": params["networkname"]}

	// prepare update model.
	update := bson.D{
		{"$set", bson.D{
			{"accesskeys", network.AccessKeys},
		}},
	}

	err = collection.FindOneAndUpdate(ctx, filter, update).Decode(&network)

	defer cancel()

	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}
	var keys []models.AccessKey
	keydata, err := json.Marshal(network.AccessKeys)
	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}

	json.Unmarshal(keydata, &keys)

	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(keys)
}