package provider

import (
	"fmt"
	"strings"

	"github.com/qdm12/gluetun/internal/constants"
	"github.com/qdm12/gluetun/internal/models"
	"github.com/qdm12/golibs/network"
)

type cyberghost struct {
	servers []models.CyberghostServer
}

func newCyberghost(servers []models.CyberghostServer) *cyberghost {
	return &cyberghost{
		servers: servers,
	}
}

func (c *cyberghost) filterServers(region, group string) (servers []models.CyberghostServer) {
	allServers := constants.CyberghostServers()
	for i, server := range allServers {
		if len(region) == 0 {
			server.Region = ""
		}
		if len(group) == 0 {
			server.Group = ""
		}
		if strings.EqualFold(server.Region, region) && strings.EqualFold(server.Group, group) {
			servers = append(servers, allServers[i])
		}
	}
	return servers
}

func (c *cyberghost) GetOpenVPNConnections(selection models.ServerSelection) (connections []models.OpenVPNConnection, err error) {
	servers := c.filterServers(selection.Region, selection.Group)
	if len(servers) == 0 {
		return nil, fmt.Errorf("no server found for region %q and group %q", selection.Region, selection.Group)
	}

	for _, server := range servers {
		for _, IP := range server.IPs {
			if selection.TargetIP != nil {
				if selection.TargetIP.Equal(IP) {
					return []models.OpenVPNConnection{{IP: IP, Port: 443, Protocol: selection.Protocol}}, nil
				}
			} else {
				connections = append(connections, models.OpenVPNConnection{IP: IP, Port: 443, Protocol: selection.Protocol})
			}
		}
	}

	if selection.TargetIP != nil {
		return nil, fmt.Errorf("target IP %s not found in IP addresses", selection.TargetIP)
	}

	if len(connections) > 64 {
		connections = connections[:64]
	}

	return connections, nil
}

func (c *cyberghost) BuildConf(connections []models.OpenVPNConnection, verbosity, uid, gid int, root bool, cipher, auth string, extras models.ExtraConfigOptions) (lines []string) {
	if len(cipher) == 0 {
		cipher = aes256cbc
	}
	if len(auth) == 0 {
		auth = "SHA256"
	}
	lines = []string{
		"client",
		"dev tun",
		"nobind",
		"persist-key",
		"persist-tun",
		"remote-cert-tls server",

		// Cyberghost specific
		// "redirect-gateway def1",
		"ncp-disable",
		"ping 5",
		"explicit-exit-notify 2",
		"script-security 2",
		"route-delay 5",

		// Added constant values
		"auth-nocache",
		"mute-replay-warnings",
		"pull-filter ignore \"auth-token\"", // prevent auth failed loops
		"auth-retry nointeract",
		"remote-random",
		"suppress-timestamps",

		// Modified variables
		fmt.Sprintf("verb %d", verbosity),
		fmt.Sprintf("auth-user-pass %s", constants.OpenVPNAuthConf),
		fmt.Sprintf("proto %s", connections[0].Protocol),
		fmt.Sprintf("cipher %s", cipher),
		fmt.Sprintf("auth %s", auth),
	}
	if strings.HasSuffix(cipher, "-gcm") {
		lines = append(lines, "ncp-ciphers AES-256-GCM:AES-256-CBC:AES-128-GCM")
	}
	if !root {
		lines = append(lines, "user nonrootuser")
	}
	for _, connection := range connections {
		lines = append(lines, fmt.Sprintf("remote %s %d", connection.IP, connection.Port))
	}
	lines = append(lines, []string{
		"<ca>",
		"-----BEGIN CERTIFICATE-----",
		constants.CyberghostCertificate,
		"-----END CERTIFICATE-----",
		"</ca>",
	}...)
	lines = append(lines, []string{
		"<cert>",
		"-----BEGIN CERTIFICATE-----",
		constants.CyberghostClientCertificate,
		"-----END CERTIFICATE-----",
		"</cert>",
	}...)
	lines = append(lines, []string{
		"<key>",
		"-----BEGIN PRIVATE KEY-----",
		extras.ClientKey,
		"-----END PRIVATE KEY-----",
		"</key>",
		"",
	}...)
	return lines
}

func (c *cyberghost) GetPortForward(client network.Client) (port uint16, err error) {
	panic("port forwarding is not supported for cyberghost")
}