#ifndef _NET_TCP_H
#define _NET_TCP_H

#include <net/net.h>

#define TCP_FLAG_FIN 0x01
#define TCP_FLAG_SYN 0x02
#define TCP_FLAG_RST 0x04
#define TCP_FLAG_PSH 0x08
#define TCP_FLAG_ACK 0x10
#define TCP_FLAG_URG 0x20

#define TCP_STATE_CLOSED      0
#define TCP_STATE_LISTEN      1
#define TCP_STATE_SYN_SENT    2
#define TCP_STATE_SYN_RCVD    3
#define TCP_STATE_ESTABLISHED 4
#define TCP_STATE_FIN_WAIT1   5
#define TCP_STATE_FIN_WAIT2   6
#define TCP_STATE_CLOSE_WAIT  7
#define TCP_STATE_CLOSING     8
#define TCP_STATE_LAST_ACK    9
#define TCP_STATE_TIME_WAIT   10

typedef struct {
    uint16_t src_port;
    uint16_t dst_port;
    uint32_t seq_num;
    uint32_t ack_num;
    uint8_t  data_offset_reserved;
    uint8_t  flags;
    uint16_t window_size;
    uint16_t checksum;
    uint16_t urgent_pointer;
} __attribute__((packed)) tcp_header_t;

typedef struct tcp_conn {
    uint32_t local_ip;
    uint32_t remote_ip;
    uint16_t local_port;
    uint16_t remote_port;
    uint8_t  state;
    uint32_t seq_num;
    uint32_t ack_num;
    bool     in_use;
} tcp_conn_t;

void tcp_init(void);
void tcp_receive(const uint8_t* packet, uint16_t length, uint32_t src_ip);
void tcp_send_packet(uint32_t dst_ip, uint16_t src_port, uint16_t dst_port,
                     uint32_t seq, uint32_t ack, uint8_t flags,
                     const void* payload, uint16_t payload_len);

size_t tcp_get_connections_count(void);
const tcp_conn_t* tcp_get_connection(size_t index);

#endif // _NET_TCP_H