#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>

#define NGX_MUNINN_MODULE        0x42000000
#define NGX_MUNINN_CONF          0x00000086

#define MUN_DNS_LEGACY_UDP_SZ    512
#define MUN_DEFAULT_CONN_POOL_SZ 1024


/* TODO: (in muninn.h)
 * need a global tree structure for storing records.
 * should store both nameservers, empty non-leaves, and leaf node DNS records.
 *
 * if possible some text hashing function for fast lookup.
 *
 * cache lookup should return closest matching record in tree
 *
 * data structure needs to be atomic
 *
 * STORE IN SHARED MEMORY
 */

typedef struct mun_dns_request {
    ngx_chain_t *in, *out;
    ngx_pool_t  *pool;
    ngx_log_t   *log;
    ngx_uint_t   err_ct;
    //TODO: record cache lookup closest result

    ngx_event_t     *ev;
    struct sockaddr *client;

    struct dep_list {
        struct mun_dns_request *dependency;
        struct dep_list        *next;
    } *dependencies;

    struct mun_dns_request *dependent;
} mun_dns_request;


// request phase handlers
void mun_dns_cache_lookup(ngx_event_t *ev);
void mun_dns_prep_record_fetch(ngx_event_t *ev);
void mun_dns_record_fetch(ngx_event_t *ev);
void mun_postpone_request(ngx_event_t *ev);
void mun_dns_record_response(ngx_event_t *ev);
void mun_handle_request_error(ngx_event_t *ev);
void mun_request_teardown(ngx_event_t *ev);