/* SPDX-License-Identifier: MIT
 *
 * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
 */

package conf

import (
	"fmt"
	"strings"
)

func (conf *Config) ToWgQuick() string {
	var output strings.Builder
	output.WriteString("[Interface]\n")

	output.WriteString(fmt.Sprintf("PrivateKey = %s\n", conf.Interface.PrivateKey.String()))

	if conf.Interface.ListenPort > 0 {
		output.WriteString(fmt.Sprintf("ListenPort = %d\n", conf.Interface.ListenPort))
	}

	if len(conf.Interface.Addresses) > 0 {
		addrStrings := make([]string, len(conf.Interface.Addresses))
		for i, address := range conf.Interface.Addresses {
			addrStrings[i] = address.String()
		}
		output.WriteString(fmt.Sprintf("Address = %s\n", strings.Join(addrStrings[:], ", ")))
	}

	if len(conf.Interface.Dns) > 0 {
		addrStrings := make([]string, len(conf.Interface.Dns))
		for i, address := range conf.Interface.Dns {
			addrStrings[i] = address.String()
		}
		output.WriteString(fmt.Sprintf("DNS = %s\n", strings.Join(addrStrings[:], ", ")))
	}

	if conf.Interface.Mtu > 0 {
		output.WriteString(fmt.Sprintf("MTU = %d\n", conf.Interface.Mtu))
	}

	for _, peer := range conf.Peers {
		output.WriteString("\n[Peer]\n")

		output.WriteString(fmt.Sprintf("PublicKey = %s\n", peer.PublicKey.String()))

		if !peer.PresharedKey.IsZero() {
			output.WriteString(fmt.Sprintf("PresharedKey = %s\n", peer.PresharedKey.String()))
		}

		if len(peer.AllowedIPs) > 0 {
			addrStrings := make([]string, len(peer.AllowedIPs))
			for i, address := range peer.AllowedIPs {
				addrStrings[i] = address.String()
			}
			output.WriteString(fmt.Sprintf("AllowedIPs = %s\n", strings.Join(addrStrings[:], ", ")))
		}

		if !peer.Endpoint.IsEmpty() {
			output.WriteString(fmt.Sprintf("Endpoint = %s\n", peer.Endpoint.String()))
		}

		if peer.PersistentKeepalive > 0 {
			output.WriteString(fmt.Sprintf("PersistentKeepalive = %d\n", peer.PersistentKeepalive))
		}
	}
	return output.String()
}

func (conf *Config) ToUAPI() (uapi string, dnsErr error) {
	var output strings.Builder
	output.WriteString(fmt.Sprintf("private_key=%s\n", conf.Interface.PrivateKey.HexString()))

	if conf.Interface.ListenPort > 0 {
		output.WriteString(fmt.Sprintf("listen_port=%d\n", conf.Interface.ListenPort))
	}

	if len(conf.Peers) > 0 {
		output.WriteString("replace_peers=true\n")
	}

	for _, peer := range conf.Peers {
		output.WriteString(fmt.Sprintf("public_key=%s\n", peer.PublicKey.HexString()))

		if !peer.PresharedKey.IsZero() {
			output.WriteString(fmt.Sprintf("preshared_key = %s\n", peer.PresharedKey.String()))
		}

		if !peer.Endpoint.IsEmpty() {
			var resolvedIp string
			resolvedIp, dnsErr = resolveHostname(peer.Endpoint.Host)
			if dnsErr != nil {
				return
			}
			resolvedEndpoint := Endpoint{resolvedIp, peer.Endpoint.Port}
			output.WriteString(fmt.Sprintf("endpoint=%s\n", resolvedEndpoint.String()))
		}

		output.WriteString(fmt.Sprintf("persistent_keepalive_interval=%d\n", peer.PersistentKeepalive))

		if len(peer.AllowedIPs) > 0 {
			output.WriteString("replace_allowed_ips=true\n")
			for _, address := range peer.AllowedIPs {
				output.WriteString(fmt.Sprintf("allowed_ip=%s\n", address.String()))
			}
		}
	}
	return output.String(), nil
}