/*

 * Copyright (c) 2022 Fastly, Inc, Goro Fuji, Kazuho Oku

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to

 * deal in the Software without restriction, including without limitation the

 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or

 * sell copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS

 * IN THE SOFTWARE.

 */

#include "h2o.h"

static int on_req(h2o_handler_t *_self, h2o_req_t *req)

{

    struct sockaddr_storage local;

    float sample_ratio = 1;

    char *trace = h2o_mem_alloc(req->path.len + 2 /* should be enough */), *trace_tail = trace;

    char *sni = h2o_mem_alloc(req->path.len + 2 /* should be enough */), *sni_tail = sni;

    char *address = h2o_mem_alloc(req->path.len + 2 /* should be enough */), *address_tail = address;

    int appdata = 0, ret;

    h2o_socket_t *sock;

    h2o_socket_export_t export_info;

    /* delegate the request to the next handler unless the request is accepted on a UNIX socket */

    if (!(req->conn->callbacks->get_sockname(req->conn, (struct sockaddr *)&local) > 0 && local.ss_family == AF_UNIX)) {

        ret = -1;

        goto Exit;

    }

    /* parse params */

    if (req->query_at != SIZE_MAX) {

        h2o_iovec_t iter = h2o_iovec_init(req->path.base + req->query_at + 1, req->path.len - (req->query_at + 1)), value;

        const char *name;

        size_t name_len;

        while ((name = h2o_next_token(&iter, '&', '&', &name_len, &value)) != NULL) {

            if (h2o_memis(name, name_len, H2O_STRLIT("sample-ratio"))) {

                if (sscanf(h2o_uri_unescape(&req->pool, value.base, value.len).base, "%f", &sample_ratio) != 1 ||

                    !(0 <= sample_ratio && sample_ratio <= 1)) {

                    h2o_send_error_400(req, "Bad Request", "sample-rate must be a number between 0 and 1", 0);

                    ret = 0;

                    goto Exit;

                }

            } else if (h2o_memis(name, name_len, H2O_STRLIT("trace"))) {

                h2o_iovec_t unescaped = h2o_uri_unescape(&req->pool, value.base, value.len);

                h2o_memcpy(trace_tail, unescaped.base, unescaped.len);

                trace_tail += unescaped.len;

                *trace_tail++ = '\0';

            } else if (h2o_memis(name, name_len, H2O_STRLIT("sni"))) {

                h2o_iovec_t unescaped = h2o_uri_unescape(&req->pool, value.base, value.len);

                h2o_memcpy(sni_tail, unescaped.base, unescaped.len);

                sni_tail += unescaped.len;

                *sni_tail++ = '\0';

            } else if (h2o_memis(name, name_len, H2O_STRLIT("address"))) {

                h2o_iovec_t unescaped = h2o_uri_unescape(&req->pool, value.base, value.len);

                h2o_memcpy(address_tail, unescaped.base, unescaped.len);

                address_tail += unescaped.len;

                *address_tail++ = '\0';

            } else if (h2o_memis(name, name_len, H2O_STRLIT("application-data"))) {

                appdata = 1;

            }

        }

    }

    /* termninate lists */

    *trace_tail = '\0';

    *sni_tail = '\0';

    *address_tail = '\0';

    /* steal the socket (NOTE: request, including `req->pool` is dipsosed of here, do we want to delay?) */

    if (req->conn->callbacks->steal_socket == NULL || (sock = req->conn->callbacks->steal_socket(req->conn)) == NULL) {

        h2o_send_error_400(req, "Bad Request", "h2olog is available only for cleartext HTTP/1", 0);

        ret = 0;

        goto Exit;

    }

    if (h2o_socket_export(sock, &export_info) != 0)

        h2o_fatal("h2o_socket_export failed");

    (void)write(export_info.fd, H2O_STRLIT("HTTP/1.1 200 OK\r\n\r\n"));

    /* register log fd after writing HTTP response, as log is written by multiple threads */

    if (ptls_log_add_fd(export_info.fd, sample_ratio, trace, sni, address, appdata) != 0)

        h2o_fatal("failed to add fd to h2olog");

    ret = 0;

Exit:

    free(trace);

    free(sni);

    free(address);

    return ret;

}

void h2o_log_register(h2o_hostconf_t *hostconf)

{

    h2o_pathconf_t *pathconf = h2o_config_register_path(hostconf, H2O_LOG_URI_PATH, 0);

    h2o_handler_t *self = h2o_create_handler(pathconf, sizeof(*self));

    self->on_req = on_req;

}