package controller

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

	"github.com/gorilla/mux"
	"github.com/gravitl/netmaker/database"
	"github.com/gravitl/netmaker/functions"
	"github.com/gravitl/netmaker/logger"
	"github.com/gravitl/netmaker/logic"
	"github.com/gravitl/netmaker/models"
	"github.com/gravitl/netmaker/mq"
	"github.com/skip2/go-qrcode"
)

func extClientHandlers(r *mux.Router) {

	r.HandleFunc("/api/extclients", securityCheck(false, http.HandlerFunc(getAllExtClients))).Methods("GET")
	r.HandleFunc("/api/extclients/{network}", securityCheck(false, http.HandlerFunc(getNetworkExtClients))).Methods("GET")
	r.HandleFunc("/api/extclients/{network}/{clientid}", securityCheck(false, http.HandlerFunc(getExtClient))).Methods("GET")
	r.HandleFunc("/api/extclients/{network}/{clientid}/{type}", securityCheck(false, http.HandlerFunc(getExtClientConf))).Methods("GET")
	r.HandleFunc("/api/extclients/{network}/{clientid}", securityCheck(false, http.HandlerFunc(updateExtClient))).Methods("PUT")
	r.HandleFunc("/api/extclients/{network}/{clientid}", securityCheck(false, http.HandlerFunc(deleteExtClient))).Methods("DELETE")
	r.HandleFunc("/api/extclients/{network}/{nodeid}", securityCheck(false, http.HandlerFunc(createExtClient))).Methods("POST")
}

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

//Gets all extclients associated with network, including pending extclients
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))
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}

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

//A separate function to get all extclients, not just extclients for a particular network.
//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")

	headerNetworks := r.Header.Get("networks")
	networksSlice := []string{}
	marshalErr := json.Unmarshal([]byte(headerNetworks), &networksSlice)
	if marshalErr != nil {
		logger.Log(0, "error unmarshalling networks: ",
			marshalErr.Error())
		returnErrorResponse(w, r, formatError(marshalErr, "internal"))
		return
	}
	clients := []models.ExtClient{}
	var err error
	if networksSlice[0] == ALL_NETWORK_ACCESS {
		clients, err = functions.GetAllExtClients()
		if err != nil && !database.IsEmptyRecord(err) {
			logger.Log(0, "failed to get all extclients: ", err.Error())
			returnErrorResponse(w, r, formatError(err, "internal"))
			return
		}
	} else {
		for _, network := range networksSlice {
			extclients, err := logic.GetNetworkExtClients(network)
			if err == nil {
				clients = append(clients, extclients...)
			}
		}
	}

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

//Get an individual extclient. Nothin fancy here folks.
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))
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}

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

//Get an individual extclient. Nothin fancy here folks.
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))
		returnErrorResponse(w, r, formatError(err, "internal"))
		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))
		returnErrorResponse(w, r, 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)
		returnErrorResponse(w, r, 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 := gwnode.Endpoint + ":" + strconv.Itoa(int(gwnode.ListenPort))
	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 network.DefaultExtClientDNS != "" {
		defaultDNS = "DNS = " + network.DefaultExtClientDNS
	}

	defaultMTU := 1420
	if gwnode.MTU != 0 {
		defaultMTU = int(gwnode.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,
		gwnode.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())
			returnErrorResponse(w, r, 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())
			returnErrorResponse(w, r, 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())
			returnErrorResponse(w, r, formatError(err, "internal"))
		}
		return
	}
	logger.Log(2, r.Header.Get("user"), "retrieved ext client config")
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(client)
}

/**
 * To create a extclient
 * Must have valid key and be unique
 */
func createExtClient(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")

	var params = mux.Vars(r)

	networkName := params["network"]
	nodeid := params["nodeid"]
	ingressExists := checkIngressExists(nodeid)
	if !ingressExists {
		err := errors.New("ingress does not exist")
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to create extclient on network [%s]: %v", networkName, err))
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}

	var extclient models.ExtClient
	extclient.Network = networkName
	extclient.IngressGatewayID = nodeid
	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))
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}
	extclient.IngressGatewayEndpoint = node.Endpoint + ":" + strconv.FormatInt(int64(node.ListenPort), 10)

	extclient.Enabled = true
	parentNetwork, err := logic.GetNetwork(networkName)
	if err == nil { // check if parent network default ACL is enabled (yes) or not (no)
		extclient.Enabled = parentNetwork.DefaultACL == "yes"
	}
	err = logic.CreateExtClient(&extclient)
	if err != nil {
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to create new ext client on network [%s]: %v", networkName, err))
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}
	logger.Log(0, r.Header.Get("user"), "created new ext client on network", networkName)
	w.WriteHeader(http.StatusOK)
	err = mq.PublishExtPeerUpdate(&node)
	if err != nil {
		logger.Log(1, "error setting ext peers on "+nodeid+": "+err.Error())
	}
}

func updateExtClient(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")

	var params = mux.Vars(r)

	var newExtClient models.ExtClient
	var oldExtClient models.ExtClient
	err := json.NewDecoder(r.Body).Decode(&newExtClient)
	if err != nil {
		logger.Log(0, r.Header.Get("user"), "error decoding request body: ",
			err.Error())
		returnErrorResponse(w, r, formatError(err, "badrequest"))
		return
	}
	clientid := params["clientid"]
	network := params["network"]
	key, err := logic.GetRecordKey(clientid, network)
	if err != nil {
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to get record key for client [%s], network [%s]: %v",
				clientid, network, err))
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}
	data, err := database.FetchRecord(database.EXT_CLIENT_TABLE_NAME, key)
	if err != nil {
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to fetch  ext client record key [%s] from db for client [%s], network [%s]: %v",
				key, clientid, network, err))
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}
	if err = json.Unmarshal([]byte(data), &oldExtClient); err != nil {
		logger.Log(0, "error unmarshalling extclient: ",
			err.Error())
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}
	var changedEnabled = newExtClient.Enabled != oldExtClient.Enabled // indicates there was a change in enablement
	newclient, err := logic.UpdateExtClient(newExtClient.ClientID, params["network"], newExtClient.Enabled, &oldExtClient)
	if err != nil {
		logger.Log(0, r.Header.Get("user"),
			fmt.Sprintf("failed to update ext client [%s], network [%s]: %v",
				clientid, network, err))
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}
	logger.Log(0, r.Header.Get("user"), "updated ext client", newExtClient.ClientID)
	if changedEnabled { // need to send a peer update to the ingress node as enablement of one of it's clients has changed
		if ingressNode, err := logic.GetNodeByID(newclient.IngressGatewayID); err == nil {
			if err = mq.PublishExtPeerUpdate(&ingressNode); err != nil {
				logger.Log(1, "error setting ext peers on", ingressNode.ID, ":", err.Error())
			}
		}
	}
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(newclient)
}

//Delete a extclient
//Pretty straightforward
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 delete extclient [%s],network [%s]: %v", clientid, network, err))
		returnErrorResponse(w, r, formatError(err, "internal"))
		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))
		returnErrorResponse(w, r, 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"])
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}

	err = mq.PublishExtPeerUpdate(&ingressnode)
	if err != nil {
		logger.Log(1, "error setting ext peers on "+ingressnode.ID+": "+err.Error())
	}
	logger.Log(0, r.Header.Get("user"),
		"Deleted extclient client", params["clientid"], "from network", params["network"])
	returnSuccessResponse(w, r, params["clientid"]+" deleted.")
}