package controller

import (
	"encoding/json"
	"errors"
	"fmt"
	"net"
	"net/http"
	"strconv"

	"github.com/gorilla/mux"
	"github.com/gravitl/netmaker/database"
	"github.com/gravitl/netmaker/logger"
	"github.com/gravitl/netmaker/logic"
	"github.com/gravitl/netmaker/servercfg"

	"github.com/gravitl/netmaker/models"

	"github.com/gravitl/netmaker/mq"
	"github.com/skip2/go-qrcode"
	"golang.org/x/exp/slog"
	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
)

func extClientHandlers(r *mux.Router) {

	r.HandleFunc("/api/extclients", logic.SecurityCheck(true, http.HandlerFunc(getAllExtClients))).Methods(http.MethodGet)
	r.HandleFunc("/api/extclients/{network}", logic.SecurityCheck(true, http.HandlerFunc(getNetworkExtClients))).Methods(http.MethodGet)
	r.HandleFunc("/api/extclients/{network}/{clientid}", logic.SecurityCheck(false, http.HandlerFunc(getExtClient))).Methods(http.MethodGet)
	r.HandleFunc("/api/extclients/{network}/{clientid}/{type}", logic.SecurityCheck(false, http.HandlerFunc(getExtClientConf))).Methods(http.MethodGet)
	r.HandleFunc("/api/extclients/{network}/{clientid}", logic.SecurityCheck(false, http.HandlerFunc(updateExtClient))).Methods(http.MethodPut)
	r.HandleFunc("/api/extclients/{network}/{clientid}", logic.SecurityCheck(false, http.HandlerFunc(deleteExtClient))).Methods(http.MethodDelete)
	r.HandleFunc("/api/extclients/{network}/{nodeid}", logic.SecurityCheck(false, checkFreeTierLimits(limitChoiceMachines, http.HandlerFunc(createExtClient)))).Methods(http.MethodPost)
}

func checkIngressExists(nodeID string) bool {
	node, err := logic.GetNodeByID(nodeID)
	if err != nil {
		return false
	}
	return node.IsIngressGateway
}

// swagger:route GET /api/extclients/{network} ext_client getNetworkExtClients
//
// Get all extclients associated with network.
// Gets all extclients associated with network, including pending extclients.
//
//			Schemes: https
//
//			Security:
//	  		oauth
//
//			Responses:
//				200: extClientSliceResponse
func getNetworkExtClients(w http.ResponseWriter, r *http.Request) {

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

	var extclients []models.ExtClient
	var params = mux.Vars(r)
	network := params["network"]
	extclients, err := logic.GetNetworkExtClients(network)
	if err != nil {
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to get ext clients for network [%s]: %v", network, err))
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}

	//Returns all the extclients in JSON format
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(extclients)
}

// swagger:route GET /api/extclients ext_client getAllExtClients
//
// A separate function to get all extclients, not just extclients for a particular network.
//
//			Schemes: https
//
//			Security:
//	  		oauth
//
//			Responses:
//				200: extClientSliceResponse
//
// Not quite sure if this is necessary. Probably necessary based on front end but may
// want to review after iteration 1 if it's being used or not
func getAllExtClients(w http.ResponseWriter, r *http.Request) {

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

	clients, err := logic.GetAllExtClients()
	if err != nil && !database.IsEmptyRecord(err) {
		logger.Log(0, "failed to get all extclients: ", err.Error())
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}
	//Return all the extclients in JSON format
	logic.SortExtClient(clients[:])
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(clients)
}

// swagger:route GET /api/extclients/{network}/{clientid} ext_client getExtClient
//
// Get an individual extclient.
//
//			Schemes: https
//
//			Security:
//	  		oauth
//
//			Responses:
//				200: extClientResponse
func getExtClient(w http.ResponseWriter, r *http.Request) {
	// set header.
	w.Header().Set("Content-Type", "application/json")

	var params = mux.Vars(r)

	clientid := params["clientid"]
	network := params["network"]
	client, err := logic.GetExtClient(clientid, network)
	if err != nil {
		logger.Log(0, r.Header.Get("user"), fmt.Sprintf("failed to get extclient for [%s] on network [%s]: %v",
			clientid, network, err))
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}
	if !logic.IsUserAllowedAccessToExtClient(r.Header.Get("user"), client) {
		// check if user has access to extclient
		slog.Error("failed to get extclient", "network", network, "clientID",
			clientid, "error", errors.New("access is denied"))
		logic.ReturnErrorResponse(w, r, logic.FormatError(errors.New("access is denied"), "forbidden"))
		return

	}

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

// swagger:route GET /api/extclients/{network}/{clientid}/{type} ext_client getExtClientConf
//
// Get an individual extclient.
//
//			Schemes: https
//
//			Security:
//	  		oauth
//
//			Responses:
//				200: extClientResponse
func getExtClientConf(w http.ResponseWriter, r *http.Request) {
	// set header.
	w.Header().Set("Content-Type", "application/json")

	var params = mux.Vars(r)
	clientid := params["clientid"]
	networkid := params["network"]
	client, err := logic.GetExtClient(clientid, networkid)
	if err != nil {
		logger.Log(0, r.Header.Get("user"), fmt.Sprintf("failed to get extclient for [%s] on network [%s]: %v",
			clientid, networkid, err))
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}
	if !logic.IsUserAllowedAccessToExtClient(r.Header.Get("user"), client) {
		slog.Error("failed to get extclient", "network", networkid, "clientID",
			clientid, "error", errors.New("access is denied"))
		logic.ReturnErrorResponse(w, r, logic.FormatError(errors.New("access is denied"), "forbidden"))
		return
	}

	gwnode, err := logic.GetNodeByID(client.IngressGatewayID)
	if err != nil {
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to get ingress gateway node [%s] info: %v", client.IngressGatewayID, err))
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}
	host, err := logic.GetHost(gwnode.HostID.String())
	if err != nil {
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to get host for ingress gateway node [%s] info: %v", client.IngressGatewayID, err))
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}

	network, err := logic.GetParentNetwork(client.Network)
	if err != nil {
		logger.Log(1, r.Header.Get("user"), "Could not retrieve Ingress Gateway Network", client.Network)
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}

	addrString := client.Address
	if addrString != "" {
		addrString += "/32"
	}
	if client.Address6 != "" {
		if addrString != "" {
			addrString += ","
		}
		addrString += client.Address6 + "/128"
	}

	keepalive := ""
	if network.DefaultKeepalive != 0 {
		keepalive = "PersistentKeepalive = " + strconv.Itoa(int(network.DefaultKeepalive))
	}
	gwendpoint := ""
	if host.EndpointIP.To4() == nil {
		gwendpoint = fmt.Sprintf("[%s]:%d", host.EndpointIP.String(), host.ListenPort)
	} else {
		gwendpoint = fmt.Sprintf("%s:%d", host.EndpointIP.String(), host.ListenPort)
	}
	var newAllowedIPs string
	if logic.IsInternetGw(gwnode) {
		egressrange := "0.0.0.0/0"
		if gwnode.Address6.IP != nil && client.Address6 != "" {
			egressrange += "," + "::/0"
		}
		newAllowedIPs = egressrange
	} else {
		newAllowedIPs = network.AddressRange
		if newAllowedIPs != "" && network.AddressRange6 != "" {
			newAllowedIPs += ","
		}
		if network.AddressRange6 != "" {
			newAllowedIPs += network.AddressRange6
		}
		if egressGatewayRanges, err := logic.GetEgressRangesOnNetwork(&client); err == nil {
			for _, egressGatewayRange := range egressGatewayRanges {
				newAllowedIPs += "," + egressGatewayRange
			}
		}
	}

	defaultDNS := ""
	if client.DNS != "" {
		defaultDNS = "DNS = " + client.DNS
	} else if gwnode.IngressDNS != "" {
		defaultDNS = "DNS = " + gwnode.IngressDNS
	}

	defaultMTU := 1420
	if host.MTU != 0 {
		defaultMTU = host.MTU
	}
	config := fmt.Sprintf(`[Interface]
Address = %s
PrivateKey = %s
MTU = %d
%s

[Peer]
PublicKey = %s
AllowedIPs = %s
Endpoint = %s
%s

`, addrString,
		client.PrivateKey,
		defaultMTU,
		defaultDNS,
		host.PublicKey,
		newAllowedIPs,
		gwendpoint,
		keepalive)

	if params["type"] == "qr" {
		bytes, err := qrcode.Encode(config, qrcode.Medium, 220)
		if err != nil {
			logger.Log(1, r.Header.Get("user"), "failed to encode qr code: ", err.Error())
			logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
			return
		}
		w.Header().Set("Content-Type", "image/png")
		w.WriteHeader(http.StatusOK)
		_, err = w.Write(bytes)
		if err != nil {
			logger.Log(1, r.Header.Get("user"), "response writer error (qr) ", err.Error())
			logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
			return
		}
		return
	}

	if params["type"] == "file" {
		name := client.ClientID + ".conf"
		w.Header().Set("Content-Type", "application/config")
		w.Header().Set("Content-Disposition", "attachment; filename=\""+name+"\"")
		w.WriteHeader(http.StatusOK)
		_, err := fmt.Fprint(w, config)
		if err != nil {
			logger.Log(1, r.Header.Get("user"), "response writer error (file) ", err.Error())
			logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		}
		return
	}
	logger.Log(2, r.Header.Get("user"), "retrieved ext client config")
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(client)
}

// swagger:route POST /api/extclients/{network}/{nodeid} ext_client createExtClient
//
// Create an individual extclient.  Must have valid key and be unique.
//
//			Schemes: https
//
//			Security:
//	  		oauth
//			Responses:
//			200:  okResponse
func createExtClient(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")

	var params = mux.Vars(r)
	nodeid := params["nodeid"]

	ingressExists := checkIngressExists(nodeid)
	if !ingressExists {
		err := errors.New("ingress does not exist")
		slog.Error("failed to create extclient", "user", r.Header.Get("user"), "error", err)
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
		return
	}
	var customExtClient models.CustomExtClient

	if err := json.NewDecoder(r.Body).Decode(&customExtClient); err != nil {
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
		return
	}
	if err := validateCustomExtClient(&customExtClient, true); err != nil {
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
		return
	}
	node, err := logic.GetNodeByID(nodeid)
	if err != nil {
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to get ingress gateway node [%s] info: %v", nodeid, err))
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}
	var userName string
	if r.Header.Get("ismaster") == "yes" {
		userName = logic.MasterUser
	} else {
		caller, err := logic.GetUser(r.Header.Get("user"))
		if err != nil {
			logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
			return
		}
		userName = caller.UserName
		if _, ok := caller.RemoteGwIDs[nodeid]; (!caller.IsAdmin && !caller.IsSuperAdmin) && !ok {
			err = errors.New("permission denied")
			slog.Error("failed to create extclient", "error", err)
			logic.ReturnErrorResponse(w, r, logic.FormatError(err, "forbidden"))
			return
		}
		// check if user has a config already for remote access client
		extclients, err := logic.GetNetworkExtClients(node.Network)
		if err != nil {
			slog.Error("failed to get extclients", "error", err)
			logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
			return
		}
		for _, extclient := range extclients {
			if extclient.RemoteAccessClientID != "" &&
				extclient.RemoteAccessClientID == customExtClient.RemoteAccessClientID && nodeid == extclient.IngressGatewayID {
				// extclient on the gw already exists for the remote access client
				err = errors.New("remote client config already exists on the gateway. it may have been created by another user with this same remote client machine")
				slog.Error("failed to create extclient", "user", userName, "error", err)
				logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
				return
			}
		}
	}

	extclient := logic.UpdateExtClient(&models.ExtClient{}, &customExtClient)
	extclient.OwnerID = userName
	extclient.RemoteAccessClientID = customExtClient.RemoteAccessClientID
	extclient.IngressGatewayID = nodeid

	// set extclient dns to ingressdns if extclient dns is not explicitly set
	if (extclient.DNS == "") && (node.IngressDNS != "") {
		extclient.DNS = node.IngressDNS
	}

	extclient.Network = node.Network
	host, err := logic.GetHost(node.HostID.String())
	if err != nil {
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to get ingress gateway host for node [%s] info: %v", nodeid, err))
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}
	listenPort := logic.GetPeerListenPort(host)
	extclient.IngressGatewayEndpoint = fmt.Sprintf("%s:%d", host.EndpointIP.String(), listenPort)
	extclient.Enabled = true
	parentNetwork, err := logic.GetNetwork(node.Network)
	if err == nil { // check if parent network default ACL is enabled (yes) or not (no)
		extclient.Enabled = parentNetwork.DefaultACL == "yes"
	}

	if err := logic.SetClientDefaultACLs(&extclient); err != nil {
		slog.Error("failed to set default acls for extclient", "user", r.Header.Get("user"), "network", node.Network, "error", err)
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}

	if err = logic.CreateExtClient(&extclient); err != nil {
		slog.Error("failed to create extclient", "user", r.Header.Get("user"), "network", node.Network, "error", err)
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}

	slog.Info("created extclient", "user", r.Header.Get("user"), "network", node.Network, "clientid", extclient.ClientID)
	w.WriteHeader(http.StatusOK)
	go func() {
		if err := mq.PublishPeerUpdate(false); err != nil {
			logger.Log(1, "error setting ext peers on "+nodeid+": "+err.Error())
		}
		if servercfg.IsDNSMode() {
			logic.SetDNS()
		}
	}()
}

// swagger:route PUT /api/extclients/{network}/{clientid} ext_client updateExtClient
//
// Update an individual extclient.
//
//			Schemes: https
//
//			Security:
//	  		oauth
//
//			Responses:
//				200: extClientResponse
func updateExtClient(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")

	var params = mux.Vars(r)

	var update models.CustomExtClient
	//var oldExtClient models.ExtClient
	var sendPeerUpdate bool
	err := json.NewDecoder(r.Body).Decode(&update)
	if err != nil {
		logger.Log(0, r.Header.Get("user"), "error decoding request body: ",
			err.Error())
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
		return
	}
	clientid := params["clientid"]
	network := params["network"]
	oldExtClient, err := logic.GetExtClientByName(clientid)
	if err != nil {
		slog.Error("failed to retrieve extclient", "user", r.Header.Get("user"), "id", clientid, "error", err)
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}
	if !logic.IsUserAllowedAccessToExtClient(r.Header.Get("user"), oldExtClient) {
		// check if user has access to extclient
		slog.Error("failed to get extclient", "network", network, "clientID",
			clientid, "error", errors.New("access is denied"))
		logic.ReturnErrorResponse(w, r, logic.FormatError(errors.New("access is denied"), "forbidden"))
		return

	}
	if oldExtClient.ClientID == update.ClientID {
		if err := validateCustomExtClient(&update, false); err != nil {
			logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
			return
		}
	} else {
		if err := validateCustomExtClient(&update, true); err != nil {
			logic.ReturnErrorResponse(w, r, logic.FormatError(err, "badrequest"))
			return
		}
	}
	var changedID = update.ClientID != oldExtClient.ClientID

	if len(update.DeniedACLs) != len(oldExtClient.DeniedACLs) {
		sendPeerUpdate = true
		logic.SetClientACLs(&oldExtClient, update.DeniedACLs)
	}
	if !logic.IsSlicesEqual(update.ExtraAllowedIPs, oldExtClient.ExtraAllowedIPs) {
		sendPeerUpdate = true
	}

	if update.Enabled != oldExtClient.Enabled {
		sendPeerUpdate = true
	}
	newclient := logic.UpdateExtClient(&oldExtClient, &update)
	if err := logic.DeleteExtClient(oldExtClient.Network, oldExtClient.ClientID); err != nil {

		slog.Error("failed to delete ext client", "user", r.Header.Get("user"), "id", oldExtClient.ClientID, "network", oldExtClient.Network, "error", err)
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}
	if err := logic.SaveExtClient(&newclient); err != nil {
		slog.Error("failed to save ext client", "user", r.Header.Get("user"), "id", newclient.ClientID, "network", newclient.Network, "error", err)
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}
	logger.Log(0, r.Header.Get("user"), "updated ext client", update.ClientID)
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(newclient)

	go func() {
		if changedID && servercfg.IsDNSMode() {
			logic.SetDNS()
		}
		if sendPeerUpdate { // need to send a peer update to the ingress node as enablement of one of it's clients has changed
			ingressNode, err := logic.GetNodeByID(newclient.IngressGatewayID)
			if err == nil {
				if err = mq.PublishPeerUpdate(false); err != nil {
					logger.Log(1, "error setting ext peers on", ingressNode.ID.String(), ":", err.Error())
				}
			}
			if !update.Enabled {
				ingressHost, err := logic.GetHost(ingressNode.HostID.String())
				if err != nil {
					slog.Error("Failed to get ingress host", "node", ingressNode.ID.String(), "error", err)
					return
				}
				nodes, err := logic.GetAllNodes()
				if err != nil {
					slog.Error("Failed to get nodes", "error", err)
					return
				}
				go mq.PublishSingleHostPeerUpdate(ingressHost, nodes, nil, []models.ExtClient{oldExtClient}, false)
			}
		}

	}()

}

// swagger:route DELETE /api/extclients/{network}/{clientid} ext_client deleteExtClient
//
// Delete an individual extclient.
//
//			Schemes: https
//
//			Security:
//	  		oauth
//
//			Responses:
//				200: successResponse
func deleteExtClient(w http.ResponseWriter, r *http.Request) {
	// Set header
	w.Header().Set("Content-Type", "application/json")

	// get params
	var params = mux.Vars(r)
	clientid := params["clientid"]
	network := params["network"]
	extclient, err := logic.GetExtClient(clientid, network)
	if err != nil {
		err = errors.New("Could not delete extclient " + params["clientid"])
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to get extclient [%s],network [%s]: %v", clientid, network, err))
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}
	if !logic.IsUserAllowedAccessToExtClient(r.Header.Get("user"), extclient) {
		slog.Error("user not allowed to delete", "network", network, "clientID",
			clientid, "error", errors.New("access is denied"))
		logic.ReturnErrorResponse(w, r, logic.FormatError(errors.New("access is denied"), "forbidden"))
		return
	}
	ingressnode, err := logic.GetNodeByID(extclient.IngressGatewayID)
	if err != nil {
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to get ingress gateway node [%s] info: %v", extclient.IngressGatewayID, err))
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}

	err = logic.DeleteExtClient(params["network"], params["clientid"])
	if err != nil {
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to delete extclient [%s],network [%s]: %v", clientid, network, err))
		err = errors.New("Could not delete extclient " + params["clientid"])
		logic.ReturnErrorResponse(w, r, logic.FormatError(err, "internal"))
		return
	}

	go func() {
		if err := mq.PublishDeletedClientPeerUpdate(&extclient); err != nil {
			logger.Log(1, "error setting ext peers on "+ingressnode.ID.String()+": "+err.Error())
		}
		if servercfg.IsDNSMode() {
			logic.SetDNS()
		}
	}()

	logger.Log(0, r.Header.Get("user"),
		"Deleted extclient client", params["clientid"], "from network", params["network"])
	logic.ReturnSuccessResponse(w, r, params["clientid"]+" deleted.")
}

// validateCustomExtClient	Validates the extclient object
func validateCustomExtClient(customExtClient *models.CustomExtClient, checkID bool) error {
	//validate clientid
	if customExtClient.ClientID != "" {
		if err := isValid(customExtClient.ClientID, checkID); err != nil {
			return fmt.Errorf("client validatation: %v", err)
		}
	}
	//extclient.ClientID = customExtClient.ClientID
	if len(customExtClient.PublicKey) > 0 {
		if _, err := wgtypes.ParseKey(customExtClient.PublicKey); err != nil {
			return errInvalidExtClientPubKey
		}
		//extclient.PublicKey = customExtClient.PublicKey
	}
	//validate extra ips
	if len(customExtClient.ExtraAllowedIPs) > 0 {
		for _, ip := range customExtClient.ExtraAllowedIPs {
			if _, _, err := net.ParseCIDR(ip); err != nil {
				return errInvalidExtClientExtraIP
			}
		}
		//extclient.ExtraAllowedIPs = customExtClient.ExtraAllowedIPs
	}
	//validate DNS
	if customExtClient.DNS != "" {
		if ip := net.ParseIP(customExtClient.DNS); ip == nil {
			return errInvalidExtClientDNS
		}
		//extclient.DNS = customExtClient.DNS
	}
	return nil
}

// isValid	Checks if the clientid is valid
func isValid(clientid string, checkID bool) error {
	if !validName(clientid) {
		return errInvalidExtClientID
	}
	if checkID {
		extclients, err := logic.GetAllExtClients()
		if err != nil {
			return fmt.Errorf("extclients isValid: %v", err)
		}
		for _, extclient := range extclients {
			if clientid == extclient.ClientID {
				return errDuplicateExtClientName
			}
		}
	}
	return nil
}