/*
 * Ouroboros - Copyright (C) 2016
 *
 * RIB manager of the IPC Process
 *
 *    Sander Vrijders <sander.vrijders@intec.ugent.be>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#define OUROBOROS_PREFIX "rib-manager"

#include <ouroboros/config.h>
#include <ouroboros/logs.h>
#include <ouroboros/cdap.h>
#include <ouroboros/list.h>
#include <ouroboros/time_utils.h>
#include <ouroboros/ipcp-dev.h>

#include <stdlib.h>
#include <pthread.h>
#include <string.h>
#include <errno.h>

#include "ribmgr.h"
#include "dt_const.h"
#include "frct.h"
#include "ipcp.h"
#include "cdap_request.h"

#include "static_info.pb-c.h"
typedef StaticInfoMsg static_info_msg_t;

#define ENROLLMENT  "enrollment"
#define STATIC_INFO "static DIF information"

struct mgmt_flow {
        struct cdap *    instance;
        int              fd;
        struct list_head next;
};

struct {
        struct dt_const  dtc;

        uint32_t         address;

        struct list_head flows;
        pthread_rwlock_t flows_lock;

        struct list_head cdap_reqs;
        pthread_mutex_t  cdap_reqs_lock;
} rib;

/* Call while holding cdap_reqs_lock */
/* FIXME: better not to call blocking functions under any lock */
int cdap_result_wait(struct cdap * instance,
                     enum cdap_opcode code,
                     char * name,
                     int invoke_id)
{
        struct cdap_request * req;
        int ret;
        char * name_dup = strdup(name);
        if (name_dup == NULL)
                return -1;

        req = cdap_request_create(code, name_dup, invoke_id, instance);
        if (req == NULL) {
                free(name_dup);
                return -1;
        }

        list_add(&req->next, &rib.cdap_reqs);

        pthread_mutex_unlock(&rib.cdap_reqs_lock);

        ret = cdap_request_wait(req);

        pthread_mutex_lock(&rib.cdap_reqs_lock);

        if (ret == -1)  /* should only be on ipcp shutdown */
                LOG_DBG("Waiting CDAP request destroyed.");

        if (ret == -ETIMEDOUT)
                LOG_ERR("CDAP Request timed out.");

        if (ret)
                LOG_DBG("Unknown error code: %d.", ret);

        if (!ret)
                ret = req->result;

        list_del(&req->next);
        cdap_request_destroy(req);

        return ret;
}

int ribmgr_init()
{
        INIT_LIST_HEAD(&rib.flows);
        INIT_LIST_HEAD(&rib.cdap_reqs);

        if (pthread_rwlock_init(&rib.flows_lock, NULL)) {
                LOG_ERR("Failed to initialize rwlock.");
                return -1;
        }

        if (pthread_mutex_init(&rib.cdap_reqs_lock, NULL)) {
                LOG_ERR("Failed to initialize mutex.");
                return -1;
        }

        return 0;
}

int ribmgr_fini()
{
        struct list_head * pos = NULL;
        struct list_head * n = NULL;

        pthread_mutex_lock(&rib.cdap_reqs_lock);
        list_for_each_safe(pos, n, &rib.cdap_reqs) {
                struct cdap_request * req =
                        list_entry(pos, struct cdap_request, next);
                free(req->name);
                list_del(&req->next);
                free(req);
        }
        pthread_mutex_unlock(&rib.cdap_reqs_lock);

        pthread_rwlock_wrlock(&rib.flows_lock);
        list_for_each_safe(pos, n, &rib.flows) {
                struct mgmt_flow * flow =
                        list_entry(pos, struct mgmt_flow, next);
                if (cdap_destroy(flow->instance))
                        LOG_ERR("Failed to destroy CDAP instance.");
                list_del(&flow->next);
                free(flow);
        }
        pthread_rwlock_unlock(&rib.flows_lock);

        pthread_mutex_destroy(&rib.cdap_reqs_lock);
        pthread_rwlock_destroy(&rib.flows_lock);

        return 0;
}

int ribmgr_cdap_reply(struct cdap * instance,
                      int           invoke_id,
                      int           result,
                      uint8_t *     data,
                      size_t        len)
{
        struct list_head * pos, * n = NULL;

        (void) data;
        (void) len;

        pthread_mutex_lock(&rib.cdap_reqs_lock);

        list_for_each_safe(pos, n, &rib.cdap_reqs) {
                struct cdap_request * req =
                        list_entry(pos, struct cdap_request, next);
                if (req->instance == instance &&
                    req->invoke_id == invoke_id &&
                    req->state == REQ_PENDING) {
                        if (result != 0)
                                LOG_ERR("CDAP command with code %d and name %s "
                                        "failed with error %d",
                                        req->code, req->name, result);
                        else
                                LOG_DBG("CDAP command with code %d and name %s "
                                        "executed succesfully",
                                        req->code, req->name);

                        pthread_mutex_unlock(&rib.cdap_reqs_lock);

                        /* FIXME: In case of a read, update values here */
                        cdap_request_respond(req, result);

                        pthread_mutex_lock(&rib.cdap_reqs_lock);
                }
        }
        pthread_mutex_unlock(&rib.cdap_reqs_lock);

        return 0;
}

int ribmgr_cdap_read(struct cdap * instance,
                     int           invoke_id,
                     char *        name)
{
        LOG_MISSING;
        (void) instance;
        (void) invoke_id;
        (void) name;

        return -1;
}

int ribmgr_cdap_write(struct cdap * instance,
                      int           invoke_id,
                      char *        name,
                      uint8_t *     data,
                      size_t        len,
                      uint32_t      flags)
{
        static_info_msg_t * msg;
        int ret = 0;

        (void) flags;

        pthread_rwlock_wrlock(&ipcpi.state_lock);
        if (ipcp_get_state() == IPCP_PENDING_ENROLL &&
            strcmp(name, STATIC_INFO) == 0) {
                LOG_DBG("Received static DIF information.");

                msg = static_info_msg__unpack(NULL, len, data);
                if (msg == NULL) {
                        ipcp_set_state(IPCP_INIT);
                        pthread_rwlock_unlock(&ipcpi.state_lock);
                        cdap_send_reply(instance, invoke_id, -1, NULL, 0);
                        LOG_ERR("Failed to unpack static info message.");
                        return -1;
                }

                rib.dtc.addr_size = msg->addr_size;
                rib.dtc.cep_id_size = msg->cep_id_size;
                rib.dtc.pdu_length_size = msg->pdu_length_size;
                rib.dtc.seqno_size = msg->seqno_size;
                rib.dtc.has_ttl = msg->has_ttl;
                rib.dtc.has_chk = msg->has_chk;
                rib.dtc.min_pdu_size = msg->min_pdu_size;
                rib.dtc.max_pdu_size = msg->max_pdu_size;

                rib.address = msg->address;

                if (frct_init()) {
                        ipcp_set_state(IPCP_INIT);
                        pthread_rwlock_unlock(&ipcpi.state_lock);
                        cdap_send_reply(instance, invoke_id, -1, NULL, 0);
                        static_info_msg__free_unpacked(msg, NULL);
                        LOG_ERR("Failed to init FRCT");
                        return -1;
                }

                static_info_msg__free_unpacked(msg, NULL);
        } else {
                ret = -1;
        }

        pthread_rwlock_unlock(&ipcpi.state_lock);

        if (cdap_send_reply(instance, invoke_id, ret, NULL, 0)) {
                LOG_ERR("Failed to send reply to write request.");
                return -1;
        }

        return 0;
}

int ribmgr_cdap_create(struct cdap * instance,
                       int           invoke_id,
                       char *        name,
                       uint8_t *     data,
                       size_t        len)
{
        LOG_MISSING;
        (void) instance;
        (void) invoke_id;
        (void) name;
        (void) data;
        (void) len;

        return -1;
}

int ribmgr_cdap_delete(struct cdap * instance,
                       int           invoke_id,
                       char *        name,
                       uint8_t *     data,
                       size_t        len)
{
        LOG_MISSING;
        (void) instance;
        (void) invoke_id;
        (void) name;
        (void) data;
        (void) len;

        return -1;
}

int ribmgr_cdap_start(struct cdap * instance,
                      int           invoke_id,
                      char *        name)
{
        static_info_msg_t stat_info = STATIC_INFO_MSG__INIT;
        uint8_t * data = NULL;
        size_t len = 0;
        int iid = 0;

        pthread_rwlock_wrlock(&ipcpi.state_lock);
        if (ipcp_get_state() == IPCP_ENROLLED &&
            strcmp(name, ENROLLMENT) == 0) {
                LOG_DBG("New enrollment request.");

                if (cdap_send_reply(instance, invoke_id, 0, NULL, 0)) {
                        pthread_rwlock_unlock(&ipcpi.state_lock);
                        LOG_ERR("Failed to send reply to enrollment request.");
                        return -1;
                }

                stat_info.addr_size = rib.dtc.addr_size;
                stat_info.cep_id_size = rib.dtc.cep_id_size;
                stat_info.pdu_length_size = rib.dtc.pdu_length_size;
                stat_info.seqno_size = rib.dtc.seqno_size;
                stat_info.has_ttl = rib.dtc.has_ttl;
                stat_info.has_chk = rib.dtc.has_chk;
                stat_info.min_pdu_size  = rib.dtc.min_pdu_size;
                stat_info.max_pdu_size = rib.dtc.max_pdu_size;

                /* FIXME: Hand out an address. */
                stat_info.address = 0;

                len = static_info_msg__get_packed_size(&stat_info);
                if (len == 0) {
                        pthread_rwlock_unlock(&ipcpi.state_lock);
                        LOG_ERR("Failed to get size of static information.");
                        return -1;
                }

                data = malloc(len);
                if (data == NULL) {
                        pthread_rwlock_unlock(&ipcpi.state_lock);
                        LOG_ERR("Failed to allocate memory.");
                        return -1;
                }

                static_info_msg__pack(&stat_info, data);

                LOG_DBGF("Sending static info...");

                pthread_mutex_lock(&rib.cdap_reqs_lock);

                iid = cdap_send_write(instance, STATIC_INFO, data, len, 0);
                if (iid < 0) {
                        pthread_mutex_unlock(&rib.cdap_reqs_lock);
                        pthread_rwlock_unlock(&ipcpi.state_lock);
                        free(data);
                        LOG_ERR("Failed to send static information.");
                        return -1;
                }

                if (cdap_result_wait(instance, WRITE, STATIC_INFO, iid)) {
                        pthread_mutex_unlock(&rib.cdap_reqs_lock);
                        pthread_rwlock_unlock(&ipcpi.state_lock);
                        free(data);
                        LOG_ERR("Remote did not receive static information.");
                        return -1;
                }
                pthread_mutex_unlock(&rib.cdap_reqs_lock);

                /* FIXME: Send neighbors here. */

                LOG_DBGF("Sending stop enrollment...");

                pthread_mutex_lock(&rib.cdap_reqs_lock);

                iid = cdap_send_stop(instance, ENROLLMENT);
                if (iid < 0) {
                        pthread_mutex_unlock(&rib.cdap_reqs_lock);
                        pthread_rwlock_unlock(&ipcpi.state_lock);
                        free(data);
                        LOG_ERR("Failed to send stop of enrollment.");
                        return -1;
                }

                if (cdap_result_wait(instance, STOP, ENROLLMENT, iid)) {
                        pthread_mutex_unlock(&rib.cdap_reqs_lock);
                        pthread_rwlock_unlock(&ipcpi.state_lock);
                        free(data);
                        LOG_ERR("Remote failed to complete enrollment.");
                        return -1;
                }
                pthread_mutex_unlock(&rib.cdap_reqs_lock);

                free(data);
        } else {
                if (cdap_send_reply(instance, invoke_id, -1, NULL, 0)) {
                        pthread_rwlock_unlock(&ipcpi.state_lock);
                        LOG_ERR("Failed to send reply to start request.");
                        return -1;
                }
        }
        pthread_rwlock_unlock(&ipcpi.state_lock);

        return 0;
}

int ribmgr_cdap_stop(struct cdap * instance,
                     int           invoke_id,
                     char *        name)
{
        int ret = 0;

        pthread_rwlock_wrlock(&ipcpi.state_lock);
        if (ipcp_get_state() == IPCP_PENDING_ENROLL &&
            strcmp(name, ENROLLMENT) == 0) {
                LOG_DBG("Stop enrollment received.");

                ipcp_set_state(IPCP_ENROLLED);
        } else
                ret = -1;

        if (cdap_send_reply(instance, invoke_id, ret, NULL, 0)) {
                pthread_rwlock_unlock(&ipcpi.state_lock);
                LOG_ERR("Failed to send reply to stop request.");
                return -1;
        }
        pthread_rwlock_unlock(&ipcpi.state_lock);

        return 0;
}

static struct cdap_ops ribmgr_ops = {
        .cdap_reply  = ribmgr_cdap_reply,
        .cdap_read   = ribmgr_cdap_read,
        .cdap_write  = ribmgr_cdap_write,
        .cdap_create = ribmgr_cdap_create,
        .cdap_delete = ribmgr_cdap_delete,
        .cdap_start  = ribmgr_cdap_start,
        .cdap_stop   = ribmgr_cdap_stop
};

int ribmgr_add_flow(int fd)
{
        struct cdap * instance = NULL;
        struct mgmt_flow * flow;
        int iid = 0;

        flow = malloc(sizeof(*flow));
        if (flow == NULL)
                return -1;

        instance = cdap_create(&ribmgr_ops, fd);
        if (instance == NULL) {
                LOG_ERR("Failed to create CDAP instance");
                free(flow);
                return -1;
        }

        INIT_LIST_HEAD(&flow->next);
        flow->instance = instance;
        flow->fd = fd;

        pthread_rwlock_wrlock(&ipcpi.state_lock);
        pthread_rwlock_wrlock(&rib.flows_lock);
        if (list_empty(&rib.flows) && ipcp_get_state() == IPCP_INIT) {
                ipcp_set_state(IPCP_PENDING_ENROLL);

                pthread_mutex_lock(&rib.cdap_reqs_lock);
                iid = cdap_send_start(instance,
                                      ENROLLMENT);
                if (iid < 0) {
                        pthread_mutex_unlock(&rib.cdap_reqs_lock);
                        pthread_rwlock_unlock(&rib.flows_lock);
                        pthread_rwlock_unlock(&ipcpi.state_lock);
                        LOG_ERR("Failed to start enrollment.");
                        cdap_destroy(instance);
                        free(flow);
                        return -1;
                }

                if (cdap_result_wait(instance, START, ENROLLMENT, iid)) {
                        pthread_mutex_unlock(&rib.cdap_reqs_lock);
                        pthread_rwlock_unlock(&rib.flows_lock);
                        pthread_rwlock_unlock(&ipcpi.state_lock);
                        LOG_ERR("Failed to start enrollment.");
                        cdap_destroy(instance);
                        free(flow);
                        return -1;
                }
                pthread_mutex_unlock(&rib.cdap_reqs_lock);
        }

        list_add(&flow->next, &rib.flows);
        pthread_rwlock_unlock(&rib.flows_lock);
        pthread_rwlock_unlock(&ipcpi.state_lock);

        return 0;
}

int ribmgr_remove_flow(int fd)
{
        struct list_head * pos, * n = NULL;

        pthread_rwlock_wrlock(&rib.flows_lock);
        list_for_each_safe(pos, n, &rib.flows) {
                struct mgmt_flow * flow =
                        list_entry(pos, struct mgmt_flow, next);
                if (flow->fd == fd) {
                        if (cdap_destroy(flow->instance))
                                LOG_ERR("Failed to destroy CDAP instance.");
                        list_del(&flow->next);
                        pthread_rwlock_unlock(&rib.flows_lock);
                        free(flow);
                        return 0;
                }
        }
        pthread_rwlock_unlock(&rib.flows_lock);

        return -1;
}

int ribmgr_bootstrap(struct dif_config * conf)
{
        if (conf == NULL ||
            conf->type != IPCP_NORMAL) {
                LOG_ERR("Bad DIF configuration.");
                return -1;
        }

        rib.dtc.addr_size = conf->addr_size;
        rib.dtc.cep_id_size  = conf->cep_id_size;
        rib.dtc.pdu_length_size = conf->pdu_length_size;
        rib.dtc.seqno_size = conf->seqno_size;
        rib.dtc.has_ttl = conf->has_ttl;
        rib.dtc.has_chk = conf->has_chk;
        rib.dtc.min_pdu_size = conf->min_pdu_size;
        rib.dtc.max_pdu_size = conf->max_pdu_size;

        /* FIXME: Set correct address. */
        rib.address = 0;

        if (frct_init()) {
                LOG_ERR("Failed to initialize FRCT.");
                return -1;
        }

        LOG_DBG("Bootstrapped RIB Manager.");

        return 0;
}

struct dt_const * ribmgr_dt_const()
{
        return &(rib.dtc);
}

uint32_t ribmgr_address()
{
        return rib.address;
}