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


static u_char * ngx_tcp_time(u_char *buf, time_t t);
static u_char *ngx_tcp_log_fill(ngx_tcp_session_t *s, u_char *buf);
static void ngx_tcp_log_write(ngx_tcp_session_t *s, ngx_tcp_log_t *log,
    u_char *buf, size_t len);


ngx_int_t
ngx_tcp_log_handler(ngx_tcp_session_t *s)
{
    u_char                   *line, *p;
    size_t                    len;
    ngx_uint_t                l;
    ngx_connection_t         *c;
    ngx_tcp_log_t            *log;
    ngx_open_file_t          *file;
#if (nginx_version) >= 1003010 || (nginx_version) >= 1002007 && (nginx_version) < 1003000
    ngx_tcp_log_buf_t        *buffer;
#endif
   ngx_tcp_log_srv_conf_t    *lscf;
    ngx_tcp_core_srv_conf_t  *cscf;

    ngx_log_debug0(NGX_LOG_DEBUG_TCP, s->connection->log, 0,
                   "tcp access log handler");

    cscf = ngx_tcp_get_module_srv_conf(s, ngx_tcp_core_module);
    lscf = cscf->access_log;

    if (lscf->off) {
        return NGX_OK;
    }

    c = s->connection;
    log = lscf->logs->elts;
    for (l = 0; l < lscf->logs->nelts; l++) {

        if (ngx_time() == log[l].disk_full_time) {

            /*
             * on FreeBSD writing to a full filesystem with enabled softupdates
             * may block process for much longer time than writing to non-full
             * filesystem, so we skip writing to a log for one second
             */

            continue;
        }

        len = 0;

        /* Calculate the length */
        len += sizeof("1970/09/28 12:00:00");   /* log time */
        len += NGX_INT64_LEN + 2;               /* [ngx_pid] */
        len += c->addr_text.len + 1;            /* client address */
        len += s->addr_text->len + 1;           /* this session address */
        len += sizeof("1970/09/28 12:00:00");   /* accept time */
        len += sizeof("255.255.255.255:65536"); /* upstream address */
        len += NGX_OFF_T_LEN + 1;               /* read bytes from client */
        len += NGX_OFF_T_LEN + 1;               /* write bytes to client */
        len += NGX_LINEFEED_SIZE;

        file = log[l].file;

#if (nginx_version) >= 1003010 || (nginx_version) >= 1002007 && (nginx_version) < 1003000
        if (file && file->data) {

            buffer = file->data;

            if (len > (size_t) (buffer->last - buffer->pos)) {

                ngx_tcp_log_write(s, &log[l], buffer->start,
                                  buffer->pos - buffer->start);

                buffer->pos = buffer->start;
            }

            if (len <= (size_t) (buffer->last - buffer->pos)) {

                p = buffer->pos;

                p = ngx_tcp_log_fill(s, p);

                buffer->pos = p;

                continue;
            }
        }
#else
        if (file && file->buffer) {

            if (len > (size_t) (file->last - file->pos)) {

                ngx_tcp_log_write(s, &log[l], file->buffer,
                                  file->pos - file->buffer);

                file->pos = file->buffer;
            }

            if (len <= (size_t) (file->last - file->pos)) {

                p = file->pos;

                p = ngx_tcp_log_fill(s, p);

                file->pos = p;

                continue;
            }
        }
#endif

        line = ngx_pnalloc(s->pool, len);
        if (line == NULL) {
            return NGX_ERROR;
        }

        p = line;

        p = ngx_tcp_log_fill(s, p);

        ngx_tcp_log_write(s, &log[l], line, p - line);
    }

    return NGX_OK;
}


static u_char *
ngx_tcp_time(u_char *buf, time_t t)
{
    ngx_tm_t    tm;

    ngx_localtime(t, &tm);

    return ngx_sprintf(buf, "%4d/%02d/%02d %02d:%02d:%02d",
                       tm.ngx_tm_year, tm.ngx_tm_mon,
                       tm.ngx_tm_mday, tm.ngx_tm_hour,
                       tm.ngx_tm_min, tm.ngx_tm_sec);
}


static u_char *
ngx_tcp_log_fill(ngx_tcp_session_t *s, u_char *buf) 
{
    u_char              *last;
    ngx_str_t           *name;
    ngx_connection_t    *c;
    ngx_tcp_upstream_t  *u;

    c = s->connection;

    last = ngx_cpymem(buf, ngx_cached_err_log_time.data,
            ngx_cached_err_log_time.len);

    last = ngx_sprintf(last, " [%P]", ngx_pid);
    last = ngx_sprintf(last, " %V", &c->addr_text);
    last = ngx_sprintf(last, " %V ", s->addr_text);
    last = ngx_tcp_time(last, s->start_sec);
    
    name = NULL;
    if (s->upstream) {
        u = s->upstream;
        if (u->peer.connection) {
            name = u->peer.name;
        }
    }

    if (name) {
        last = ngx_sprintf(last, " %V", name);
    }
    else {
        last = ngx_sprintf(last, " -");
    }

    last = ngx_sprintf(last, " %O", s->bytes_read);
    last = ngx_sprintf(last, " %O", s->bytes_write);

    ngx_linefeed(last);

    return last;
}


static void
ngx_tcp_log_write(ngx_tcp_session_t *s, ngx_tcp_log_t *log, u_char *buf,
    size_t len)
{
    u_char     *name;
    time_t      now;
    ssize_t     n;
    ngx_err_t   err;

    if(len == 0) return;

    name = log->file->name.data;
    n = ngx_write_fd(log->file->fd, buf, len);

    if (n == (ssize_t) len) {
        return;
    }

    now = ngx_time();

    if (n == -1) {
        err = ngx_errno;

        if (err == NGX_ENOSPC) {
            log->disk_full_time = now;
        }

        if (now - log->error_log_time > 59) {
            ngx_log_error(NGX_LOG_ALERT, s->connection->log, err,
                          ngx_write_fd_n " to \"%s\" failed", name);

            log->error_log_time = now;
        }

        return;
    }

    if (now - log->error_log_time > 59) {
        ngx_log_error(NGX_LOG_ALERT, s->connection->log, 0,
                      ngx_write_fd_n " to \"%s\" was incomplete: %z of %uz",
                      name, n, len);

        log->error_log_time = now;
    }
}