package functions

import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"log"
	"net"
	"net/http"
	"os"
	"strconv"
	"strings"

	"github.com/gravitl/netmaker/logger"
	"github.com/gravitl/netmaker/models"
	"github.com/gravitl/netmaker/netclient/config"
	"github.com/gravitl/netmaker/netclient/daemon"
	"github.com/gravitl/netmaker/netclient/local"
	"github.com/gravitl/netmaker/netclient/ncutils"
	"github.com/gravitl/netmaker/netclient/wireguard"
	"golang.zx2c4.com/wireguard/wgctrl"
)

// LINUX_APP_DATA_PATH - linux path
const LINUX_APP_DATA_PATH = "/etc/netmaker"

// ListPorts - lists ports of WireGuard devices
func ListPorts() error {
	wgclient, err := wgctrl.New()
	if err != nil {
		return err
	}
	defer wgclient.Close()
	devices, err := wgclient.Devices()
	if err != nil {
		return err
	}
	fmt.Println("Here are your ports:")
	for _, i := range devices {
		fmt.Println(i.ListenPort)
	}
	return err
}

func getPrivateAddr() (string, error) {

	var local string
	conn, err := net.Dial("udp", "8.8.8.8:80")
	if err == nil {
		defer conn.Close()

		localAddr := conn.LocalAddr().(*net.UDPAddr)
		localIP := localAddr.IP
		local = localIP.String()
	}
	if local == "" {
		local, err = getPrivateAddrBackup()
	}

	if local == "" {
		err = errors.New("could not find local ip")
	}

	return local, err
}

func getPrivateAddrBackup() (string, error) {
	ifaces, err := net.Interfaces()
	if err != nil {
		return "", err
	}
	var local string
	found := false
	for _, i := range ifaces {
		if i.Flags&net.FlagUp == 0 {
			continue // interface down
		}
		if i.Flags&net.FlagLoopback != 0 {
			continue // loopback interface
		}
		addrs, err := i.Addrs()
		if err != nil {
			return "", err
		}
		for _, addr := range addrs {
			var ip net.IP
			switch v := addr.(type) {
			case *net.IPNet:
				if !found {
					ip = v.IP
					local = ip.String()
					found = true
				}
			case *net.IPAddr:
				if !found {
					ip = v.IP
					local = ip.String()
					found = true
				}
			}
		}
	}
	if !found {
		err := errors.New("local ip address not found")
		return "", err
	}
	return local, err
}

// GetNode - gets node locally
func GetNode(network string) models.Node {

	modcfg, err := config.ReadConfig(network)
	if err != nil {
		log.Fatalf("Error: %v", err)
	}

	return modcfg.Node
}

// Uninstall - uninstalls networks from client
func Uninstall() error {
	networks, err := ncutils.GetSystemNetworks()
	if err != nil {
		logger.Log(1, "unable to retrieve networks: ", err.Error())
		logger.Log(1, "continuing uninstall without leaving networks")
	} else {
		for _, network := range networks {
			err = LeaveNetwork(network)
			if err != nil {
				logger.Log(1, "Encounter issue leaving network ", network, ": ", err.Error())
			}
		}
	}
	err = nil
	// clean up OS specific stuff
	if ncutils.IsWindows() {
		daemon.CleanupWindows()
	} else if ncutils.IsMac() {
		daemon.CleanupMac()
	} else if ncutils.IsLinux() {
		daemon.CleanupLinux()
	} else if ncutils.IsFreeBSD() {
		daemon.CleanupFreebsd()
	} else if !ncutils.IsKernel() {
		logger.Log(1, "manual cleanup required")
	}

	return err
}

// LeaveNetwork - client exits a network
func LeaveNetwork(network string) error {
	cfg, err := config.ReadConfig(network)
	if err != nil {
		return err
	}
	node := cfg.Node
	if node.IsServer != "yes" {
		token, err := Authenticate(cfg)
		if err != nil {
			logger.Log(0, "unable to authenticate: "+err.Error())
		} else {
			url := "https://" + cfg.Server.API + "/api/nodes/" + cfg.Network + "/" + cfg.Node.ID
			response, err := API("", http.MethodDelete, url, token)
			if err != nil {
				logger.Log(0, "error deleting node on server: "+err.Error())
			} else {
				if response.StatusCode == http.StatusOK {
					logger.Log(0, "deleted node", cfg.Node.Name, " on network ", cfg.Network)
				} else {
					bodybytes, _ := io.ReadAll(response.Body)
					defer response.Body.Close()
					logger.Log(0, fmt.Sprintf("error deleting node on server %s %s", response.Status, string(bodybytes)))
				}
			}
		}
	}
	wgClient, wgErr := wgctrl.New()
	if wgErr == nil {
		removeIface := cfg.Node.Interface
		queryAddr := cfg.Node.PrimaryAddress()
		if ncutils.IsMac() {
			var macIface string
			macIface, wgErr = local.GetMacIface(queryAddr)
			if wgErr == nil && removeIface != "" {
				removeIface = macIface
			}
			wgErr = nil
		}
		dev, devErr := wgClient.Device(removeIface)
		if devErr == nil {
			local.FlushPeerRoutes(removeIface, queryAddr, dev.Peers[:])
			_, cidr, cidrErr := net.ParseCIDR(cfg.NetworkSettings.AddressRange)
			if cidrErr == nil {
				local.RemoveCIDRRoute(removeIface, queryAddr, cidr)
			}
		} else {
			logger.Log(1, "could not flush peer routes when leaving network, ", cfg.Node.Network)
		}
	}

	err = WipeLocal(node.Network)
	if err != nil {
		logger.Log(1, "unable to wipe local config")
	} else {
		logger.Log(1, "removed ", node.Network, " network locally")
	}

	currentNets, err := ncutils.GetSystemNetworks()
	if err != nil || len(currentNets) <= 1 {
		daemon.Stop() // stop system daemon if last network
		return RemoveLocalInstance(cfg, network)
	}
	return daemon.Restart()
}

// RemoveLocalInstance - remove all netclient files locally for a network
func RemoveLocalInstance(cfg *config.ClientConfig, networkName string) error {

	if cfg.Daemon != "off" {
		if ncutils.IsWindows() {
			// TODO: Remove job?
		} else if ncutils.IsMac() {
			//TODO: Delete mac daemon
		} else if ncutils.IsFreeBSD() {
			daemon.RemoveFreebsdDaemon()
		} else {
			daemon.RemoveSystemDServices()
		}
	}
	return nil
}

// DeleteInterface - delete an interface of a network
func DeleteInterface(ifacename string, postdown string) error {
	return wireguard.RemoveConf(ifacename, true)
}

// WipeLocal - wipes local instance
func WipeLocal(network string) error {
	cfg, err := config.ReadConfig(network)
	if err != nil {
		return err
	}
	nodecfg := cfg.Node
	ifacename := nodecfg.Interface
	if ifacename != "" {
		if err = wireguard.RemoveConf(ifacename, true); err == nil {
			logger.Log(1, "removed WireGuard interface: ", ifacename)
		} else if strings.Contains(err.Error(), "does not exist") {
			err = nil
		}
	}

	home := ncutils.GetNetclientPathSpecific()
	if ncutils.FileExists(home + "netconfig-" + network) {
		err = os.Remove(home + "netconfig-" + network)
		if err != nil {
			log.Println("error removing netconfig:")
			log.Println(err.Error())
		}
	}
	if ncutils.FileExists(home + "backup.netconfig-" + network) {
		err = os.Remove(home + "backup.netconfig-" + network)
		if err != nil {
			log.Println("error removing backup netconfig:")
			log.Println(err.Error())
		}
	}
	if ncutils.FileExists(home + "nettoken-" + network) {
		err = os.Remove(home + "nettoken-" + network)
		if err != nil {
			log.Println("error removing nettoken:")
			log.Println(err.Error())
		}
	}
	if ncutils.FileExists(home + "secret-" + network) {
		err = os.Remove(home + "secret-" + network)
		if err != nil {
			log.Println("error removing secret:")
			log.Println(err.Error())
		}
	}
	if ncutils.FileExists(home + "traffic-" + network) {
		err = os.Remove(home + "traffic-" + network)
		if err != nil {
			log.Println("error removing traffic key:")
			log.Println(err.Error())
		}
	}
	if ncutils.FileExists(home + "wgkey-" + network) {
		err = os.Remove(home + "wgkey-" + network)
		if err != nil {
			log.Println("error removing wgkey:")
			log.Println(err.Error())
		}
	}
	if ncutils.FileExists(home + ifacename + ".conf") {
		err = os.Remove(home + ifacename + ".conf")
		if err != nil {
			log.Println("error removing .conf:")
			log.Println(err.Error())
		}
	}
	err = removeHostDNS(ifacename, ncutils.IsWindows())
	if err != nil {
		logger.Log(0, "failed to delete dns entries for", ifacename, err.Error())
	}
	return err
}

// GetNetmakerPath - gets netmaker path locally
func GetNetmakerPath() string {
	return LINUX_APP_DATA_PATH
}

//API function to interact with netmaker api endpoints. response from endpoint is returned
func API(data any, method, url, authorization string) (*http.Response, error) {
	var request *http.Request
	var err error
	if data != "" {
		payload, err := json.Marshal(data)
		if err != nil {
			return nil, fmt.Errorf("error encoding data %w", err)
		}
		request, err = http.NewRequest(method, url, bytes.NewBuffer(payload))
		if err != nil {
			return nil, fmt.Errorf("error creating http request %w", err)
		}
		request.Header.Set("Content-Type", "application/json")
	} else {
		request, err = http.NewRequest(method, url, nil)
		if err != nil {
			return nil, fmt.Errorf("error creating http request %w", err)
		}
	}
	if authorization != "" {
		request.Header.Set("authorization", "Bearer "+authorization)
	}
	client := http.Client{}
	return client.Do(request)
}

// Authenticate authenticates with api to permit subsequent interactions with the api
func Authenticate(cfg *config.ClientConfig) (string, error) {

	pass, err := os.ReadFile(ncutils.GetNetclientPathSpecific() + "secret-" + cfg.Network)
	if err != nil {
		return "", fmt.Errorf("could not read secrets file %w", err)
	}
	data := models.AuthParams{
		MacAddress: cfg.Node.MacAddress,
		ID:         cfg.Node.ID,
		Password:   string(pass),
	}
	url := "https://" + cfg.Server.API + "/api/nodes/adm/" + cfg.Network + "/authenticate"
	response, err := API(data, http.MethodPost, url, "")
	if err != nil {
		return "", err
	}
	defer response.Body.Close()
	if response.StatusCode != http.StatusOK {
		bodybytes, _ := io.ReadAll(response.Body)
		return "", fmt.Errorf("failed to authenticate %s %s", response.Status, string(bodybytes))
	}
	resp := models.SuccessResponse{}
	if err := json.NewDecoder(response.Body).Decode(&resp); err != nil {
		return "", fmt.Errorf("error decoding respone %w", err)
	}
	tokenData := resp.Response.(map[string]interface{})
	token := tokenData["AuthToken"]
	return token.(string), nil
}

// RegisterWithServer calls the register endpoint with privatekey and commonname - api returns ca and client certificate
func SetServerInfo(cfg *config.ClientConfig) error {
	cfg, err := config.ReadConfig(cfg.Network)
	if err != nil {
		return err
	}
	url := "https://" + cfg.Server.API + "/api/server/getserverinfo"
	logger.Log(1, "server at "+url)

	token, err := Authenticate(cfg)
	if err != nil {
		return err
	}
	response, err := API("", http.MethodGet, url, token)
	if err != nil {
		return err
	}
	if response.StatusCode != http.StatusOK {
		return errors.New(response.Status)
	}
	var resp models.ServerConfig
	if err := json.NewDecoder(response.Body).Decode(&resp); err != nil {
		return errors.New("unmarshal cert error " + err.Error())
	}

	// set broker information on register
	cfg.Server.Server = resp.Server
	cfg.Server.MQPort = resp.MQPort

	if err = config.ModServerConfig(&cfg.Server, cfg.Node.Network); err != nil {
		logger.Log(0, "error overwriting config with broker information: "+err.Error())
	}

	return nil
}

func informPortChange(node *models.Node) {
	if node.ListenPort == 0 {
		logger.Log(0, "UDP hole punching enabled for node", node.Name)
	} else {
		logger.Log(0, "node", node.Name, "is using port", strconv.Itoa(int(node.ListenPort)))
	}
}