/*
 * Ouroboros - Copyright (C) 2016
 *
 * The IPC Resource Manager
 *
 *    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 "irmd"

#include <ouroboros/config.h>
#include <ouroboros/logs.h>
#include <ouroboros/common.h>
#include <ouroboros/sockets.h>
#include <ouroboros/irm.h>
#include <ouroboros/ipcp.h>
#include <ouroboros/da.h>
#include <ouroboros/list.h>
#include <ouroboros/instance_name.h>
#include <ouroboros/utils.h>
#include <ouroboros/dif_config.h>
#include <ouroboros/shm_du_map.h>

#include <sys/socket.h>
#include <sys/un.h>
#include <signal.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <limits.h>

/* FIXME: this smells like part of namespace management */
#define ALL_DIFS "*"

struct ipcp_entry {
        struct list_head  next;
        pid_t             pid;
        instance_name_t * api;
        char *            dif_name;
};

/* currently supports only registering whatevercast groups of a single AP */
struct reg_name_entry {
        struct list_head next;

        /* generic whatevercast name */
        char *             name;

        /* FIXME: resolve name instead */
        instance_name_t  * api;
        uint32_t           reg_ap_id;
};

struct irm {
        /* FIXME: list of ipcps can be merged with registered names */
        struct list_head ipcps;
        struct list_head reg_names;

        struct shm_du_map * dum;
};

struct irm * instance = NULL;

static pid_t find_pid_by_ipcp_name(instance_name_t * api)
{
        struct list_head * pos = NULL;

        list_for_each(pos, &instance->ipcps) {
                struct ipcp_entry * tmp =
                        list_entry(pos, struct ipcp_entry, next);

                if (instance_name_cmp(api, tmp->api) == 0)
                        return tmp->pid;
        }

        return 0;
}

static struct ipcp_entry * find_ipcp_by_name(instance_name_t * api)
{
        struct ipcp_entry * tmp = NULL;
        struct list_head * pos = NULL;

        list_for_each(pos, &instance->ipcps) {
                struct ipcp_entry * tmp =
                        list_entry(pos, struct ipcp_entry, next);

                if (instance_name_cmp(api, tmp->api) == 0)
                        return tmp;
        }

        return tmp;
}

static pid_t find_pid_by_dif_name(char * dif_name)
{
        struct list_head * pos = NULL;

        list_for_each(pos, &instance->ipcps) {
                struct ipcp_entry * tmp =
                        list_entry(pos, struct ipcp_entry, next);

                if (tmp->dif_name == NULL)
                        return tmp->pid;

                if (strcmp(dif_name, tmp->dif_name) == 0)
                        return tmp->pid;
        }

        return 0;
}

static struct reg_name_entry * reg_name_entry_create()
{
        struct reg_name_entry * e = malloc(sizeof(*e));
        if (e == NULL)
                return NULL;

        e->reg_ap_id = rand() % INT_MAX;
        e->name  = NULL;

        INIT_LIST_HEAD(&e->next);

        return e;
}

static struct reg_name_entry * reg_name_entry_init(struct reg_name_entry * e,
                                                   char *                  name,
                                                   instance_name_t       * api)
{
        if (e == NULL || name == NULL || api == NULL)
                return NULL;

        e->name = name;
        e->api  = api;

        return e;
}

static int reg_name_entry_destroy(struct reg_name_entry * e)
{
        if (e == NULL)
                return 0;

        free(e->name);
        instance_name_destroy(e->api);
        return 0;
}

static struct reg_name_entry * find_reg_name_entry_by_name(char * name)
{
        struct list_head * pos = NULL;

        list_for_each(pos, &instance->reg_names) {
                struct reg_name_entry * e =
                        list_entry(pos, struct reg_name_entry, next);

                if (strcmp(name, e->name) == 0)
                        return e;
        }

        return NULL;
}

static struct reg_name_entry * find_reg_name_entry_by_id(uint32_t reg_ap_id)
{
        struct list_head * pos = NULL;

        list_for_each(pos, &instance->reg_names) {
                struct reg_name_entry * e =
                        list_entry(pos, struct reg_name_entry, next);

                if (reg_ap_id == e->reg_ap_id)
                        return e;
        }

        return NULL;
}

/* FIXME: add only name when we have NSM solved */
static int reg_name_entry_add_name_instance(char * name, instance_name_t * api)
{
        struct reg_name_entry * e = find_reg_name_entry_by_name(name);
        if (e == NULL) {
                e = reg_name_entry_create();
                e = reg_name_entry_init(e, name, api);
                list_add(&e->next, &instance->reg_names);
                return 0;
        }

        /* already exists, we don't have NSM yet */
        return -1;
}

static int reg_name_entry_del_name(char * name)
{
        struct reg_name_entry * e = find_reg_name_entry_by_name(name);
        if (e == NULL)
                return 0;

        list_del(&e->next);

        reg_name_entry_destroy(e);

        return 0;
}

static int create_ipcp(instance_name_t * api,
                       enum ipcp_type    ipcp_type)
{
        pid_t pid;
        struct ipcp_entry * tmp = NULL;

        pid = ipcp_create(api, ipcp_type);
        if (pid == -1) {
                LOG_ERR("Failed to create IPCP");
                return -1;
        }

        tmp = malloc(sizeof(*tmp));
        if (tmp == NULL) {
                return -1;
        }

        INIT_LIST_HEAD(&tmp->next);

        tmp->pid = pid;
        tmp->api = instance_name_dup(api);
        if (tmp->api == NULL) {
                free(tmp);
                return -1;
        }

        tmp->dif_name = NULL;

        LOG_DBG("Created IPC process with pid %d", pid);

        list_add(&tmp->next, &instance->ipcps);
        return 0;
}

static int destroy_ipcp(instance_name_t * api)
{
        pid_t pid = 0;
        struct list_head * pos = NULL;
        struct list_head * n = NULL;

        pid = find_pid_by_ipcp_name(api);
        if (pid == 0) {
                LOG_ERR("No such IPCP");
                return -1;
        }

        LOG_DBG("Destroying ipcp with pid %d", pid);

        if (ipcp_destroy(pid))
                LOG_ERR("Could not destroy IPCP");

        list_for_each_safe(pos, n, &(instance->ipcps)) {
                struct ipcp_entry * tmp =
                        list_entry(pos, struct ipcp_entry, next);

                if (instance_name_cmp(api, tmp->api) == 0)
                        list_del(&tmp->next);
        }

        return 0;
}

static int bootstrap_ipcp(instance_name_t *  api,
                          dif_config_msg_t * conf)
{
        struct ipcp_entry * entry = NULL;

        entry = find_ipcp_by_name(api);
        if (entry == NULL) {
                LOG_ERR("No such IPCP");
                return -1;
        }

        entry->dif_name = strdup(conf->dif_name);
        if (entry->dif_name == NULL) {
                LOG_ERR("Failed to strdup");
                return -1;
        }

        if (ipcp_bootstrap(entry->pid, conf)) {
                LOG_ERR("Could not bootstrap IPCP");
                free(entry->dif_name);
                entry->dif_name = NULL;
                return -1;
        }

        return 0;
}

static int enroll_ipcp(instance_name_t  * api,
                       char *             dif_name)
{
        char *  member = NULL;
        char ** n_1_difs = NULL;
        ssize_t n_1_difs_size = 0;
        struct ipcp_entry * entry = NULL;

        entry = find_ipcp_by_name(api);
        if (entry == NULL) {
                LOG_ERR("No such IPCP");
                return -1;
        }

        entry->dif_name = strdup(dif_name);
        if (entry->dif_name == NULL) {
                LOG_ERR("Failed to strdup");
                return -1;
        }

        member = da_resolve_daf(dif_name);
        if (member == NULL) {
                LOG_ERR("Could not find a member of that DIF");
                free(entry->dif_name);
                entry->dif_name = NULL;
                return -1;
        }

        n_1_difs_size = da_resolve_dap(member, n_1_difs);
        if (n_1_difs_size < 1) {
                LOG_ERR("Could not find N-1 DIFs");
                free(entry->dif_name);
                entry->dif_name = NULL;
                return -1;
        }

        if (ipcp_enroll(entry->pid, member, n_1_difs[0])) {
                LOG_ERR("Could not enroll IPCP");
                free(entry->dif_name);
                entry->dif_name = NULL;
                return -1;
        }

        return 0;
}

static int reg_ipcp(instance_name_t * api,
                    char **           difs,
                    size_t            difs_size)
{
        pid_t pid = 0;

        pid = find_pid_by_ipcp_name(api);
        if (pid == 0) {
                LOG_ERR("No such IPCP");
                return -1;
        }

        if (ipcp_reg(pid, difs, difs_size)) {
                LOG_ERR("Could not register IPCP to N-1 DIF(s)");
                return -1;
        }

        return 0;
}

static int unreg_ipcp(instance_name_t  * api,
                      char **            difs,
                      size_t             difs_size)
{
        pid_t pid = 0;

        pid = find_pid_by_ipcp_name(api);
        if (pid == 0) {
                LOG_ERR("No such IPCP");
                return -1;
        }

        if (ipcp_unreg(pid, difs, difs_size)) {
                LOG_ERR("Could not unregister IPCP from N-1 DIF(s)");
                return -1;
        }

        return 0;
}

static int ap_unreg_id(uint32_t reg_ap_id,
                       pid_t    pid,
                       char **  difs,
                       size_t   len)
{
        int i;
        int ret = 0;
        struct reg_name_entry * rne    = NULL;
        struct list_head      * pos  = NULL;

        rne = find_reg_name_entry_by_id (reg_ap_id);
        if (rne == NULL)
                return 0; /* no such id */

        if (instance->ipcps.next == NULL) {
                LOG_ERR("No IPCPs in this system.");
                return 0;
        }

        if (strcmp(difs[0], ALL_DIFS) == 0) {
                  list_for_each(pos, &instance->ipcps) {
                        struct ipcp_entry * e =
                                list_entry(pos, struct ipcp_entry, next);

                        if (ipcp_name_unreg(e->pid, rne->name)) {
                                LOG_ERR("Could not unregister %s in DIF %s.",
                                        rne->name, e->dif_name);
                                --ret;
                        }
                }
        } else {
                for (i = 0; i < len; ++i) {
                        pid = find_pid_by_dif_name(difs[i]);
                        if (pid == 0) {
                                LOG_ERR("%s: No such DIF.", difs[i]);
                                continue;
                        }

                        if (ipcp_name_unreg(pid, rne->name)) {
                                LOG_ERR("Could not unregister %s in DIF %s.",
                                        rne->name, difs[i]);
                                --ret;
                        }
                }
        }

        reg_name_entry_del_name(rne->name);

        return ret;
}

static int ap_reg(char *  ap_name,
                  pid_t   ap_id,
                  char ** difs,
                  size_t  len)
{
        pid_t pid = 0;
        int i;
        int ret = 0;
        int reg_ap_id = 0;
        struct list_head * pos = NULL;
        struct reg_name_entry * rne = NULL;
        instance_name_t * api = NULL;


        if (instance->ipcps.next == NULL)
                LOG_ERR("No IPCPs in this system.");

        /* check if this ap_name is already registered */
        rne = find_reg_name_entry_by_name(ap_name);
        if (rne != NULL)
                return -1; /* can only register one instance for now */

        rne = reg_name_entry_create();
        if (rne == NULL)
                return -1;

        api = instance_name_create();
        if (instance_name_init_from(api, ap_name, ap_id) == NULL) {
                instance_name_destroy(api);
                return -1;
        }

        /*
         * for now, the whatevercast name is the same as the ap_name and
         * contains a single instance only
         */

        if (reg_name_entry_init(rne, strdup(ap_name), api) == NULL) {
                reg_name_entry_destroy(rne);
                instance_name_destroy(api);
                return -1;
        }

        if (strcmp(difs[0], ALL_DIFS) == 0) {
                list_for_each(pos, &instance->ipcps) {
                        struct ipcp_entry * e =
                                list_entry(pos, struct ipcp_entry, next);

                        if (ipcp_name_reg(e->pid, api->name)) {
                                LOG_ERR("Could not register %s in DIF %s.",
                                        api->name, e->dif_name);
                        } else {
                                ++ret;
                        }
                }
        } else {
                for (i = 0; i < len; ++i) {
                        pid = find_pid_by_dif_name(difs[i]);
                        if (pid == 0) {
                                LOG_ERR("%s: No such DIF.", difs[i]);
                                continue;
                        }

                        if (ipcp_name_reg(pid, api->name)) {
                                LOG_ERR("Could not register %s in DIF %s.",
                                        api->name, difs[i]);
                        } else {
                                ++ret;
                        }
                }
        }

        if (ret ==  0) {
                instance_name_destroy(api);
                return -1;
        }
        /* for now, we register single instances */
        reg_name_entry_add_name_instance(strdup(ap_name), instance_name_dup(api));

        return reg_ap_id;
}

static int ap_unreg(char *  ap_name,
                    pid_t   ap_id,
                    char ** difs,
                    size_t  len)
{
        struct reg_name_entry * tmp = NULL;

        instance_name_t * api = instance_name_create();
        if (instance_name_init_from(api, ap_name, ap_id) == NULL) {
                instance_name_destroy(api);
                return -1;
        }

        /* check if ap_name is registered */
        tmp = find_reg_name_entry_by_name(api->name);
        if (tmp == NULL)
                return 0;
        else
                return ap_unreg_id(tmp->reg_ap_id, api->id, difs, len);
}


static int flow_accept(int fd,
                       char * ap_name,
                       char * ae_name)
{
        return -1;
}

static int flow_alloc_resp(int fd,
                           int result)
{

        return -1;
}

static int flow_alloc(char * dst_ap_name,
                      char * src_ap_name,
                      char * src_ae_name,
                      struct qos_spec * qos,
                      int oflags)
{
        return -1;
}

static int flow_alloc_res(int fd)
{

        return -1;
}

static int flow_dealloc(int fd)
{
        return -1;
}

static int flow_cntl(int fd,
                     int oflags)
{
        return -1;
}

static int flow_req_arr(uint32_t reg_api_id,
                        char *   ap_name,
                        char *   ae_name)
{
        return -1;
}

static int flow_alloc_reply(uint32_t port_id,
                            int      result)
{
        return -1;
}

static int flow_dealloc_ipcp(uint32_t port_id)
{
        return -1;
}

void irmd_sig_handler(int sig, siginfo_t * info, void * c)
{
        switch(sig) {
        case SIGINT:
        case SIGTERM:
        case SIGHUP:
                shm_du_map_close(instance->dum);
                free(instance);
                exit(0);
        default:
                return;
        }
}

int main()
{
        int     sockfd;
        uint8_t buf[IRM_MSG_BUF_SIZE];

        struct sigaction sig_act;

        /* init sig_act */
        memset (&sig_act, 0, sizeof sig_act);

        /* install signal traps */
        sig_act.sa_sigaction = &irmd_sig_handler;
        sig_act.sa_flags     = SA_SIGINFO;

        sigaction(SIGINT,  &sig_act, NULL);
        sigaction(SIGTERM, &sig_act, NULL);
        sigaction(SIGHUP,  &sig_act, NULL);

        if (access("/dev/shm/" SHM_DU_MAP_FILENAME, F_OK) != -1)
                unlink("/dev/shm/" SHM_DU_MAP_FILENAME);

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

        if ((instance->dum = shm_du_map_create()) == NULL)
                return -1;

        INIT_LIST_HEAD(&instance->ipcps);
        INIT_LIST_HEAD(&instance->reg_names);

        sockfd = server_socket_open(IRM_SOCK_PATH);
        if (sockfd < 0) {
                free(instance);
                return -1;
        }

        while (true) {
                int cli_sockfd;
                irm_msg_t * msg;
                ssize_t count;
                instance_name_t api;
                buffer_t buffer;
                irm_msg_t ret_msg = IRM_MSG__INIT;

                ret_msg.code = IRM_MSG_CODE__IRM_REPLY;

                cli_sockfd = accept(sockfd, 0, 0);
                if (cli_sockfd < 0) {
                        LOG_ERR("Cannot accept new connection");
                        continue;
                }

                count = read(cli_sockfd, buf, IRM_MSG_BUF_SIZE);
                if (count <= 0) {
                        LOG_ERR("Failed to read from socket");
                        close(cli_sockfd);
                        continue;
                }

                msg = irm_msg__unpack(NULL, count, buf);
                if (msg == NULL) {
                        close(cli_sockfd);
                        continue;
                }

                api.name = msg->ap_name;
                api.id   = msg->api_id;

                switch (msg->code) {
                case IRM_MSG_CODE__IRM_CREATE_IPCP:
                        ret_msg.has_result = true;
                        ret_msg.result = create_ipcp(&api,
                                                     msg->ipcp_type);
                        break;
                case IRM_MSG_CODE__IRM_DESTROY_IPCP:
                        ret_msg.has_result = true;
                        ret_msg.result = destroy_ipcp(&api);
                        break;
                case IRM_MSG_CODE__IRM_BOOTSTRAP_IPCP:
                        ret_msg.has_result = true;
                        ret_msg.result = bootstrap_ipcp(&api, msg->conf);
                        break;
                case IRM_MSG_CODE__IRM_ENROLL_IPCP:
                        ret_msg.has_result = true;
                        ret_msg.result = enroll_ipcp(&api,
                                                     msg->dif_name[0]);
                        break;
                case IRM_MSG_CODE__IRM_REG_IPCP:
                        ret_msg.has_result = true;
                        ret_msg.result = reg_ipcp(&api,
                                                  msg->dif_name,
                                                  msg->n_dif_name);
                        break;
                case IRM_MSG_CODE__IRM_UNREG_IPCP:
                        ret_msg.has_result = true;
                        ret_msg.result = unreg_ipcp(&api,
                                                    msg->dif_name,
                                                    msg->n_dif_name);
                        break;
                case IRM_MSG_CODE__IRM_AP_REG:
                        ret_msg.has_fd = true;
                        ret_msg.fd = ap_reg(msg->ap_name,
                                            msg->pid,
                                            msg->dif_name,
                                            msg->n_dif_name);
                        break;
                case IRM_MSG_CODE__IRM_AP_UNREG:
                        ret_msg.has_result = true;
                        ret_msg.result = ap_unreg(msg->ap_name,
                                                  msg->pid,
                                                  msg->dif_name,
                                                  msg->n_dif_name);
                        break;
                case IRM_MSG_CODE__IRM_FLOW_ACCEPT:
                        ret_msg.has_fd = true;
                        ret_msg.fd = flow_accept(msg->fd,
                                                 ret_msg.ap_name,
                                                 ret_msg.ae_name);
                        break;
                case IRM_MSG_CODE__IRM_FLOW_ALLOC_RESP:
                        ret_msg.has_result = true;
                        ret_msg.result = flow_alloc_resp(msg->fd,
                                                         msg->result);
                        break;
                case IRM_MSG_CODE__IRM_FLOW_ALLOC:
                        ret_msg.has_fd = true;
                        ret_msg.fd = flow_alloc(msg->dst_name,
                                                msg->ap_name,
                                                msg->ae_name,
                                                NULL,
                                                msg->oflags);
                        break;
                case IRM_MSG_CODE__IRM_FLOW_ALLOC_RES:
                        ret_msg.has_response = true;
                        ret_msg.response = flow_alloc_res(msg->fd);
                        break;
                case IRM_MSG_CODE__IRM_FLOW_DEALLOC:
                        ret_msg.has_result = true;
                        ret_msg.result = flow_dealloc(msg->fd);
                        break;
                case IRM_MSG_CODE__IRM_FLOW_CONTROL:
                        ret_msg.has_result = true;
                        ret_msg.result = flow_cntl(msg->fd,
                                                   msg->oflags);
                        break;
                case IRM_MSG_CODE__IPCP_FLOW_REQ_ARR:
                        ret_msg.has_port_id = true;
                        ret_msg.port_id = flow_req_arr(msg->port_id,
                                                       msg->ap_name,
                                                       msg->ae_name);
                        break;
                case IRM_MSG_CODE__IPCP_FLOW_ALLOC_REPLY:
                        ret_msg.has_result = true;
                        ret_msg.result = flow_alloc_reply(msg->port_id,
                                                          msg->response);
                        break;
                case IRM_MSG_CODE__IPCP_FLOW_DEALLOC:
                        ret_msg.has_result = true;
                        ret_msg.result = flow_dealloc_ipcp(msg->port_id);
                        break;
                default:
                        LOG_ERR("Don't know that message code");
                        break;
                }

                irm_msg__free_unpacked(msg, NULL);

                buffer.size = irm_msg__get_packed_size(&ret_msg);
                if (buffer.size == 0) {
                        LOG_ERR("Failed to send reply message");
                        close(cli_sockfd);
                        continue;
                }

                buffer.data = malloc(buffer.size);
                if (buffer.data == NULL) {
                        close(cli_sockfd);
                        continue;
                }

                irm_msg__pack(&ret_msg, buffer.data);

                if (write(cli_sockfd, buffer.data, buffer.size) == -1) {
                        free(buffer.data);
                        close(cli_sockfd);
                        continue;
                }

                free(buffer.data);
                close(cli_sockfd);
        }

        return 0;
}