/* http_prometheus.c -- Routines for handling Prometheus requests in httpd
 *
 * Copyright (c) 1994-2017 Carnegie Mellon University.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The name "Carnegie Mellon University" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For permission or any legal
 *    details, please contact
 *      Carnegie Mellon University
 *      Center for Technology Transfer and Enterprise Creation
 *      4615 Forbes Avenue
 *      Suite 302
 *      Pittsburgh, PA  15213
 *      (412) 268-7393, fax: (412) 268-7395
 *      innovation@andrew.cmu.edu
 *
 * 4. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by Computing Services
 *     at Carnegie Mellon University (http://www.cmu.edu/computing/)."
 *
 * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
 * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

#include <config.h>

#include "imap/httpd.h"
#include "imap/http_err.h"
#include "imap/prometheus.h"

static int prom_need_auth(struct transaction_t *txn);
static void prom_init(struct buf *);
static int prom_auth(const char *);
static void prom_reset(void);
static void prom_shutdown(void);
static int prom_get(struct transaction_t *txn, void *params);

struct namespace_t namespace_prometheus = {
    URL_NS_PROMETHEUS,
    /*enabled*/ 0,
    "prometheus",
    "/metrics",
    /* XXX .well-known url*/ NULL,
    prom_need_auth,
    /* XXX auth schemes*/ 0,
    /*mboxtype*/ 0,
    (ALLOW_READ),
    &prom_init,
    &prom_auth,
    &prom_reset,
    &prom_shutdown,
    /* XXX premethod */ NULL,
    {
        { NULL,                 NULL },                 /* ACL          */
        { NULL,                 NULL },                 /* BIND         */
        { NULL,                 NULL },                 /* CONNECT      */
        { NULL,                 NULL },                 /* COPY         */
        { NULL,                 NULL },                 /* DELETE       */
        { &prom_get,            NULL },                 /* GET          */
        { NULL,                 NULL },                 /* HEAD         */
        { NULL,                 NULL },                 /* LOCK         */
        { NULL,                 NULL },                 /* MKCALENDAR   */
        { NULL,                 NULL },                 /* MKCOL        */
        { NULL,                 NULL },                 /* MOVE         */
        { &meth_options,        NULL },                 /* OPTIONS      */
        { NULL,                 NULL },                 /* PATCH        */
        { NULL,                 NULL },                 /* POST         */
        { NULL,                 NULL },                 /* PROPFIND     */
        { NULL,                 NULL },                 /* PROPPATCH    */
        { NULL,                 NULL },                 /* PUT          */
        { NULL,                 NULL },                 /* REPORT       */
        { NULL,                 NULL },                 /* SEARCH       */
        { &meth_trace,          NULL },                 /* TRACE        */
        { NULL,                 NULL },                 /* UNBIND       */
        { NULL,                 NULL },                 /* UNLOCK       */
    },
};

static int prom_need_auth(struct transaction_t *txn __attribute__((unused)))
{
    const char *need_auth = config_getstring(IMAPOPT_PROMETHEUS_NEED_AUTH);

    if (!strcmp(need_auth, "none"))
        return 0;

    return HTTP_UNAUTHORIZED;
}

static void prom_init(struct buf *serverinfo __attribute__((unused)))
{
    namespace_prometheus.enabled =
        (config_httpmodules & IMAP_ENUM_HTTPMODULES_PROMETHEUS)
        && config_getswitch(IMAPOPT_PROMETHEUS_ENABLED);
}

static int prom_auth(const char *userid __attribute__((unused)))
{
    /* FIXME */
    return 0;
}

static void prom_reset(void)
{
    /* FIXME */
}

static void prom_shutdown(void)
{
    /* FIXME */
}

static int prom_get(struct transaction_t *txn,
                    void *params __attribute__((unused)))
{
    struct buf buf = BUF_INITIALIZER;
    const char *mimetype = NULL;
    int r;

    if (strcmp(txn->req_uri->path, "/metrics"))
        return HTTP_NOT_FOUND;

    const char *need_auth = config_getstring(IMAPOPT_PROMETHEUS_NEED_AUTH);
    if (!strcmp(need_auth, "admin") && !httpd_userisadmin)
        return HTTP_UNAUTHORIZED;
    if (!strcmp(need_auth, "user") && !httpd_userid)
        return HTTP_UNAUTHORIZED;

    r = prometheus_text_report(&buf, &mimetype);
    if (r) {
        txn->error.desc = error_message(r);
        return HTTP_SERVER_ERROR;
    }

    txn->resp_body.type = mimetype;
    txn->resp_body.len = buf_len(&buf);

    write_body(HTTP_OK, txn, buf_cstring(&buf), buf_len(&buf));

    buf_free(&buf);
    return 0;
}