#pragma once

#include <stddef.h>
#include <stdbool.h>

struct transport;

// Takes ownership of socket.
// Returns NULL and closes socket if setup fails.
struct transport* tsp_start(int fd, bool is_server);

// Also closes socket.
void tsp_close(struct transport *tsp);

// Get file descriptor that can be used in e.g. select(2) to detect possible
// data on the transport. If there is data, the tsp_recv() function must be
// used to handle it, because it may be protocol-level data for the integrity
// of the transport.
int tsp_select_fd(const struct transport *tsp);

// If successful, returns true.
// If unsuccessful, returns false and closes the transport (after which the
// transport may not be used again).
bool tsp_send(struct transport *tsp, const char *data, size_t length);

struct received_data {
	char *data;
	size_t length;
	bool error;
};
void received_data_nullify(struct received_data data);

// If no data is avilable yet, returns {.data=NULL, length=0, error=false}.
// If an error occurred, returns {.data=NULL, length=0, error=true}.
// If data is avilable, returns {.data=..., length=(length of data), error=false}.
// This function also handles protocol-level actions that do not actually
// return application-level data, but that are indeed necessary.
struct received_data tsp_recv(struct transport *tsp);