/*
 * Copyright 2016 Jakub Klama <jceel@FreeBSD.org>
 * All rights reserved
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted providing 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 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 AUTHOR 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.
 *
 */

#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <sys/queue.h>
#include "lib9p.h"
#include "lib9p_impl.h"
#include "fid.h"
#include "hashtable.h"
#include "log.h"
#include "threadpool.h"
#include "backend/backend.h"

int
l9p_server_init(struct l9p_server **serverp, struct l9p_backend *backend)
{
        struct l9p_server *server;

        server = l9p_calloc(1, sizeof (*server));
        server->ls_max_version = L9P_2000L;
        server->ls_backend = backend;
        LIST_INIT(&server->ls_conns);

        *serverp = server;
        return (0);
}

int
l9p_connection_init(struct l9p_server *server, struct l9p_connection **conn)
{
        struct l9p_connection *newconn;

        assert(server != NULL);
        assert(conn != NULL);

        newconn = calloc(1, sizeof (*newconn));
        if (newconn == NULL)
                return (-1);
        newconn->lc_server = server;
        newconn->lc_msize = L9P_DEFAULT_MSIZE;
        if (l9p_threadpool_init(&newconn->lc_tp, L9P_NUMTHREADS)) {
                free(newconn);
                return (-1);
        }
        ht_init(&newconn->lc_files, 100);
        ht_init(&newconn->lc_requests, 100);
        LIST_INSERT_HEAD(&server->ls_conns, newconn, lc_link);
        *conn = newconn;

        return (0);
}

void
l9p_connection_free(struct l9p_connection *conn)
{

        LIST_REMOVE(conn, lc_link);
        free(conn);
}

void
l9p_connection_recv(struct l9p_connection *conn, const struct iovec *iov,
    const size_t niov, void *aux)
{
        struct l9p_request *req;
        int error;

        req = l9p_calloc(1, sizeof (struct l9p_request));
        req->lr_aux = aux;
        req->lr_conn = conn;

        req->lr_req_msg.lm_mode = L9P_UNPACK;
        req->lr_req_msg.lm_niov = niov;
        memcpy(req->lr_req_msg.lm_iov, iov, sizeof (struct iovec) * niov);

        req->lr_resp_msg.lm_mode = L9P_PACK;

        if (l9p_pufcall(&req->lr_req_msg, &req->lr_req, conn->lc_version) != 0) {
                L9P_LOG(L9P_WARNING, "cannot unpack received message");
                l9p_freefcall(&req->lr_req);
                free(req);
                return;
        }

        if (ht_add(&conn->lc_requests, req->lr_req.hdr.tag, req)) {
                L9P_LOG(L9P_WARNING, "client reusing outstanding tag %d",
                    req->lr_req.hdr.tag);
                l9p_freefcall(&req->lr_req);
                free(req);
                return;
        }

        error = conn->lc_lt.lt_get_response_buffer(req,
            req->lr_resp_msg.lm_iov,
            &req->lr_resp_msg.lm_niov,
            conn->lc_lt.lt_aux);
        if (error) {
                L9P_LOG(L9P_WARNING, "cannot obtain buffers for response");
                ht_remove(&conn->lc_requests, req->lr_req.hdr.tag);
                l9p_freefcall(&req->lr_req);
                free(req);
                return;
        }

        /*
         * NB: it's up to l9p_threadpool_run to decide whether
         * to queue the work or to run it immediately and wait
         * (it must do the latter for Tflush requests).
         */
        l9p_threadpool_run(&conn->lc_tp, req);
}

void
l9p_connection_close(struct l9p_connection *conn)
{
        struct ht_iter iter;
        struct l9p_fid *fid;
        struct l9p_request *req;

        L9P_LOG(L9P_DEBUG, "waiting for thread pool to shut down");
        l9p_threadpool_shutdown(&conn->lc_tp);

        /* Drain pending requests (if any) */
        L9P_LOG(L9P_DEBUG, "draining pending requests");
        ht_iter(&conn->lc_requests, &iter);
        while ((req = ht_next(&iter)) != NULL) {
#ifdef notyet
                /* XXX would be good to know if there is anyone listening */
                if (anyone listening) {
                        /* XXX crude - ops like Tclunk should succeed */
                        req->lr_error = EINTR;
                        l9p_respond(req, false, false);
                } else
#endif
                l9p_respond(req, true, false);  /* use no-answer path */
                ht_remove_at_iter(&iter);
        }

        /* Close opened files (if any) */
        L9P_LOG(L9P_DEBUG, "closing opened files");
        ht_iter(&conn->lc_files, &iter);
        while ((fid = ht_next(&iter)) != NULL) {
                conn->lc_server->ls_backend->freefid(
                    conn->lc_server->ls_backend->softc, fid);
                free(fid);
                ht_remove_at_iter(&iter);
        }

        ht_destroy(&conn->lc_requests);
        ht_destroy(&conn->lc_files);
}

struct l9p_fid *
l9p_connection_alloc_fid(struct l9p_connection *conn, uint32_t fid)
{
        struct l9p_fid *file;

        file = l9p_calloc(1, sizeof (struct l9p_fid));
        file->lo_fid = fid;
        /*
         * Note that the new fid is not marked valid yet.
         * The insert here will fail if the fid number is
         * in use, otherwise we have an invalid fid in the
         * table (as desired).
         */

        if (ht_add(&conn->lc_files, fid, file) != 0) {
                free(file);
                return (NULL);
        }

        return (file);
}

void
l9p_connection_remove_fid(struct l9p_connection *conn, struct l9p_fid *fid)
{
        struct l9p_backend *be;

        /* fid should be marked invalid by this point */
        assert(!l9p_fid_isvalid(fid));

        be = conn->lc_server->ls_backend;
        be->freefid(be->softc, fid);

        ht_remove(&conn->lc_files, fid->lo_fid);
        free(fid);
}