#ifndef LNM_HTTP_RES
#define LNM_HTTP_RES

#include <stdbool.h>
#include <stdio.h>

#include "lnm/common.h"
#include "lnm/http/consts.h"

typedef lnm_err (*data_fn)(size_t *written, char *buf, lnm_http_conn *conn,
                           size_t offset, size_t len);

/**
 * Linked list elements used to store the response headers
 */
typedef struct lnm_http_res_header {
  struct {
    char *s;
    size_t len;
    bool owned;
  } name;
  struct {
    char *s;
    size_t len;
    bool owned;
  } value;
  struct lnm_http_res_header *next;
} lnm_http_res_header;

typedef enum lnm_http_res_body_type {
  lnm_http_res_body_type_file = 0,
  lnm_http_res_body_type_buf,
  lnm_http_res_body_type_fn,
} lnm_http_res_body_type;

typedef struct lnm_http_res {
  lnm_http_status status;
  struct {
    lnm_http_res_header *head;
    lnm_http_res_header *current;
  } headers;
  struct {
    struct {
      char *buf;
      FILE *f;
      data_fn fn;
    } data;
    uint64_t len;
    bool owned;
    lnm_http_res_body_type type;
  } body;
  // General-purpose; meaning depends on the current state
  uint64_t written;
} lnm_http_res;

/**
 * Add a new header of a known type to the response
 *
 * @param type type of header
 * @param value null-terminated string containing the value of the header
 * @param value_owned whether to take ownership of the value pointer; if false,
 * free'ing the buffer is the caller's responsibility
 */
lnm_err lnm_http_res_add_header(lnm_http_res *res, lnm_http_header type,
                                char *value, bool value_owned);

/**
 * Add a new header of a known type to the response with a given value length.
 *
 * @param type type of header
 * @param value string of length `value_len` containing the value of the header
 * @param value_len length of value
 * @param value_owned whether to take ownership of the value pointer; if false,
 * free'ing the buffer is the caller's responsibility
 */
lnm_err lnm_http_res_add_header_len(lnm_http_res *res, lnm_http_header type,
                                    char *value, size_t value_len,
                                    bool value_owned);

/**
 * Set the request body to the given file pointer.
 *
 * @param res response to modify
 * @param f file pointer to use as data
 * @param len expected length of the file
 * @param owned whether to take ownership of the file pointer
 */
void lnm_http_res_body_set_file(lnm_http_res *res, FILE *f, size_t len,
                                bool owned);

/**
 * Set the request body to the given buffer.
 *
 * @param res response to modify
 * @param buf buffer to use as data
 * @param len length of the buffer
 * @param owned whether to take ownership of the file pointer
 */
void lnm_http_res_body_set_buf(lnm_http_res *res, char *buf, size_t len,
                               bool owned);

/**
 * Set the request body to be read from the given data function.
 *
 * @param res response to modify
 * @param fn data reader function
 * @param len expected length of the response
 */
void lnm_http_res_body_set_fn(lnm_http_res *res, data_fn fn, size_t len);

/**
 * Reset the given response object, properly free'ing any allocated buffers,
 * allowing it to be reused for later connections.
 *
 * @param res res to reset
 */
void lnm_http_res_reset(lnm_http_res *res);

#endif