#ifndef __CHAINBUFFER_H__
#define __CHAINBUFFER_H__

#include <stddef.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/uio.h>

typedef struct chain_buffer_node chain_buffer_node_t;

typedef struct chain_buffer_s {
    chain_buffer_node_t *head;
    chain_buffer_node_t *tail;
    size_t total_len;
    size_t chunk_size;

    chain_buffer_node_t *free_list;
    size_t free_count;
    size_t free_limit;

    uint8_t *linear_cache;
    size_t linear_cap;
} chain_buffer_t;

typedef struct chain_buffer_list_s {
    chain_buffer_node_t *head;
    chain_buffer_node_t *tail;
    size_t total_len;
} chain_buffer_list_t;

void chain_buffer_init(chain_buffer_t *buf, size_t chunk_size);
void chain_buffer_reset(chain_buffer_t *buf);

size_t chain_buffer_len(const chain_buffer_t *buf);
int chain_buffer_append(chain_buffer_t *buf, const void *data, size_t len);
size_t chain_buffer_drain(chain_buffer_t *buf, size_t len);

const uint8_t *chain_buffer_linearize(chain_buffer_t *buf, size_t *out_len);
ssize_t chain_buffer_send_fd(chain_buffer_t *buf, int fd, int flags);

/* readv zero-copy recv helpers */
int chain_buffer_prepare_recv_iov(chain_buffer_t *buf, struct iovec *iov, int max_iov);
size_t chain_buffer_commit_recv(chain_buffer_t *buf, size_t len);

/* ownership transfer helpers */
void chain_buffer_list_init(chain_buffer_list_t *list);
size_t chain_buffer_list_len(const chain_buffer_list_t *list);
int chain_buffer_list_iov(const chain_buffer_list_t *list, struct iovec *iov, int max_iov);
int chain_buffer_detach_prefix(chain_buffer_t *buf, size_t len, chain_buffer_list_t *out);
void chain_buffer_list_release(chain_buffer_t *owner, chain_buffer_list_t *list);

#endif