/*
**  L2 - OSSP Logging Library
**  Copyright (c) 2001 The OSSP Project (http://www.ossp.org/)
**  Copyright (c) 2001 Cable & Wireless Deutschland (http://www.cw.com/de/)
**
**  This file is part of OSSP L2, a flexible logging library which
**  can be found at http://www.ossp.org/pkg/l2/.
**
**  Permission to use, copy, modify, and distribute this software for
**  any purpose with or without fee is hereby granted, provided that
**  the above copyright notice and this permission notice appear in all
**  copies.
**
**  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
**  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
**  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
**  IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR
**  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
**  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
**  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
**  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
**  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
**  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
**  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
**  SUCH DAMAGE.
**
**  l2_ch_prefix.c: prefixing channel implementation
*/

#include <time.h>

#include "l2.h"

/* declare private channel configuration */
typedef struct {
    char *timefmt;
    char *timezone;
    char  timebuf[1024];
} l2_ch_prefix_t;

/* create channel */
static l2_result_t hook_create(l2_context_t *ctx, l2_channel_t *ch)
{
    l2_ch_prefix_t *cfg;

    /* allocate private channel configuration */
    if ((cfg = (l2_ch_prefix_t *)malloc(sizeof(l2_ch_prefix_t))) == NULL)
        return L2_ERR_MEM;

    /* initialize configuration with reasonable defaults */
    cfg->timefmt  = NULL;
    cfg->timezone = strdup("local");

    /* link private channel configuration into channel context */
    ctx->vp = cfg;

    return L2_OK;
}

/* configure channel */
static l2_result_t hook_configure(l2_context_t *ctx, l2_channel_t *ch, const char *fmt, va_list ap)
{
    l2_ch_prefix_t *cfg = (l2_ch_prefix_t *)ctx->vp;
    l2_param_t pa[3]; 
    l2_result_t rv;

    /* feed and call generic parameter parsing engine */
    L2_PARAM_SET(pa[0], timefmt,  STRING, &cfg->timefmt);
    L2_PARAM_SET(pa[1], timezone, STRING, &cfg->timezone);
    L2_PARAM_END(pa[2]);
    rv = l2_util_setparams(pa, fmt, ap);

    /* argument consistency check */
    if (rv == L2_OK) {
        if (cfg->timezone == NULL)
            return L2_ERR_ARG;
        if (!(   strcmp(cfg->timezone, "local") == 0 
              || strcmp(cfg->timezone, "utc")   == 0))
            return L2_ERR_ARG;
    }

    return rv;
}

/* write to channel */
static l2_result_t hook_write(l2_context_t *ctx, l2_channel_t *ch,
                              l2_level_t level, const char *buf, size_t buf_size)
{
    l2_ch_prefix_t *cfg = (l2_ch_prefix_t *)ctx->vp;
    l2_channel_t *downstream = l2_channel_downstream(ch);
    time_t t;
    struct tm *tm;
    size_t n;
    l2_result_t rv;

    /* optionally provide prefix */
    if (cfg->timefmt != NULL) {
        t = time(NULL);
        if (strcmp(cfg->timezone, "local") == 0)
            tm = localtime(&t);
        else if (strcmp(cfg->timezone, "utc") == 0)
            tm = gmtime(&t);
        else
            return L2_ERR_ARG;
        if ((n = strftime(cfg->timebuf, sizeof(cfg->timebuf), cfg->timefmt, tm)) == 0)
            return L2_ERR_SYS;
        if ((rv = l2_channel_write(downstream, level, cfg->timebuf, n)) != L2_OK)
            return rv;
    }

    /* write to downstream channel */
    if ((rv = l2_channel_write(downstream, level, buf, buf_size)) != L2_OK)
        return rv;

    return L2_OK;
}

/* destroy channel */
static l2_result_t hook_destroy(l2_context_t *ctx, l2_channel_t *ch)
{
    l2_ch_prefix_t *cfg = (l2_ch_prefix_t *)ctx->vp;
    l2_channel_t *downstream = l2_channel_downstream(ch);
    l2_result_t rv;

    /* free prefix structure */
    if (cfg->timefmt != NULL)
        free(cfg->timefmt);
    if (cfg->timezone != NULL)
        free(cfg->timezone);
    free(cfg);

    /* optionally destroy downstream channel, too */
    if ((rv = l2_channel_destroy(downstream)) != L2_OK)
        return rv;

    return L2_OK;
}

/* exported channel handler structure */
l2_handler_t l2_handler_prefix = {
    L2_CHANNEL_FILTER,
    hook_create,
    hook_configure,
    NULL,
    hook_write,
    NULL,
    NULL,
    hook_destroy
};