#ifndef NSTUN_ENCAP_H_
#define NSTUN_ENCAP_H_

#include <stdint.h>

#include <span>
#include <vector>

#include "net_defs.h"

namespace nstun {

/* SOCKS5 constants */
constexpr uint8_t SOCKS5_VERSION = 0x05;
constexpr uint8_t SOCKS5_AUTH_NONE = 0x00;
constexpr uint8_t SOCKS5_CMD_CONNECT = 0x01;
constexpr uint8_t SOCKS5_CMD_UDP_ASSOCIATE = 0x03;
constexpr uint8_t SOCKS5_ATYP_IPV4 = 0x01;
constexpr uint8_t SOCKS5_ATYP_DOMAIN = 0x03;
constexpr uint8_t SOCKS5_ATYP_IPV6 = 0x04;
constexpr uint8_t SOCKS5_REP_SUCCESS = 0x00;

/* SOCKS5 wire structs (kept for direct protocol parsing in UDP path) */
struct __attribute__((packed)) socks5_greeting {
	uint8_t ver;
	uint8_t num_auth;
	uint8_t auth[1];
};

struct __attribute__((packed)) socks5_auth_reply {
	uint8_t ver;
	uint8_t method;
};

struct __attribute__((packed)) socks5_req {
	uint8_t ver;
	uint8_t cmd;
	uint8_t rsv;
	uint8_t atyp;
	uint32_t dst_ip4;
	uint16_t dst_port;
};

struct __attribute__((packed)) socks5_req6 {
	uint8_t ver;
	uint8_t cmd;
	uint8_t rsv;
	uint8_t atyp;
	uint8_t dst_ip6[IPV6_ADDR_LEN];
	uint16_t dst_port;
};

struct __attribute__((packed)) socks5_req_domain {
	uint8_t ver;
	uint8_t cmd;
	uint8_t rsv;
	uint8_t atyp;
	uint8_t domain_len;
};

struct __attribute__((packed)) socks5_udp_hdr {
	uint16_t rsv;
	uint8_t frag;
	uint8_t atyp;
	uint32_t dst_ip4;
	uint16_t dst_port;
};

struct __attribute__((packed)) socks5_udp_hdr6 {
	uint16_t rsv;
	uint8_t frag;
	uint8_t atyp;
	uint8_t dst_ip6[IPV6_ADDR_LEN];
	uint16_t dst_port;
};

struct __attribute__((packed)) socks5_udp_hdr_domain {
	uint16_t rsv;
	uint8_t frag;
	uint8_t atyp;
	uint8_t domain_len;
};

struct __attribute__((packed)) socks5_max_buf {
	uint8_t data[512];
};

/* Higher-level SOCKS5 helpers */
struct Socks5Reply {
	uint8_t atyp;
	uint32_t bind_ip4;
	uint16_t bind_port;
};

int send_socks5_greeting(int fd);
bool parse_socks5_auth_reply(std::span<const uint8_t> data);
int send_socks5_connect(int fd, const uint8_t* addr, uint16_t port_nbo, bool is_ipv6);
int send_socks5_udp_associate(int fd);
bool parse_socks5_connect_reply(std::span<const uint8_t> data, Socks5Reply* out);

/* HTTP CONNECT helpers */
int send_http_connect(int fd, const uint8_t* addr, uint16_t port_nbo, bool is_ipv6);
size_t find_end_of_headers(const std::vector<uint8_t>& buf);
bool parse_http_connect_reply(const std::vector<uint8_t>& buf);

} /* namespace nstun */

#endif /* NSTUN_ENCAP_H_ */