#include <sys/time.h>
#include <time.h>
#include "util/util.h"
#include "responder/common/responder_packet.h"
#include "responder/common/responder.h"
#include "providers/data_provider.h"
#include "sbus/sbus_client.h"
#include "providers/dp_sbus.h"

struct sss_dp_pvt_ctx {
    struct resp_ctx *rctx;
    struct sbus_interface *intf;

    uint16_t cli_type;
    uint16_t cli_version;
    const char *cli_name;
    const char *cli_domain;

    time_t last_retry;
    int retries;
};

hash_table_t *dp_requests = NULL;

static int sss_dp_conn_destructor(void *data);
static void sss_dp_reconnect(struct tevent_context *ev,
                             struct tevent_timer *te,
                             struct timeval tv, void *data);

static void sss_dp_conn_reconnect(struct sss_dp_pvt_ctx *pvt)
{
    struct resp_ctx *rctx;
    struct tevent_timer *te;
    struct timeval tv;
    char *sbus_address;
    time_t now;
    int ret;

    now = time(NULL);

    /* reset retry if last reconnect was > 60 sec. ago */
    if (pvt->last_retry + 60 < now) pvt->retries = 0;
    if (pvt->retries >= 3) {
        DEBUG(4, ("Too many reconnect retries! Giving up\n"));
        return;
    }

    pvt->last_retry = now;
    pvt->retries++;

    rctx = pvt->rctx;

    ret = dp_get_sbus_address(rctx, rctx->cdb, &sbus_address);
    if (ret != EOK) {
        DEBUG(0, ("Could not locate data provider address.\n"));
        return;
    }

    ret = sbus_client_init(rctx, rctx->ev, sbus_address,
                           pvt->intf, &rctx->dp_conn,
                           sss_dp_conn_destructor, pvt);

    if (ret == EOK) {
        /* Identify ourselves to the data provider */
        ret = dp_common_send_id(rctx->dp_conn,
                                pvt->cli_type, pvt->cli_version,
                                pvt->cli_name, pvt->cli_domain);
        if (ret != EOK) {
            DEBUG(0, ("Failed to identify to the data provider!\n"));
        }
    }

    if (ret != EOK) {
        DEBUG(4, ("Failed to reconnect [%d(%s)]!\n", ret, strerror(ret)));

        tv.tv_sec = now +5;
        tv.tv_usec = 0;
        te = tevent_add_timer(rctx->ev, rctx, tv, sss_dp_reconnect, pvt);
        if (te == NULL) {
            DEBUG(4, ("Failed to add timed event! Giving up\n"));
        } else {
            DEBUG(4, ("Retrying in 5 seconds\n"));
        }
    }
}

static void sss_dp_reconnect(struct tevent_context *ev,
                             struct tevent_timer *te,
                             struct timeval tv, void *data)
{
    struct sss_dp_pvt_ctx *pvt;

    pvt = talloc_get_type(data, struct sss_dp_pvt_ctx);

    sss_dp_conn_reconnect(pvt);
}

int sss_dp_conn_destructor(void *data)
{
    struct sss_dp_pvt_ctx *pvt;
    struct sbus_connection *conn;

    conn = talloc_get_type(data, struct sbus_connection);
    if (!conn) return 0;

    /* if this is a regular disconnect just quit */
    if (sbus_conn_disconnecting(conn)) return 0;

    pvt = talloc_get_type(sbus_conn_get_private_data(conn),
                          struct sss_dp_pvt_ctx);
    if (pvt) return 0;

    sss_dp_conn_reconnect(pvt);

    return 0;
}

int sss_dp_init(struct resp_ctx *rctx, struct sbus_interface *dp_intf,
                uint16_t cli_type, uint16_t cli_version,
                const char *cli_name, const char *cli_domain)
{
    int ret;
    struct sss_dp_pvt_ctx *pvt;

    pvt = talloc_zero(rctx, struct sss_dp_pvt_ctx);
    if (!pvt) return ENOMEM;

    pvt->rctx = rctx;
    pvt->intf = dp_intf;
    pvt->cli_type = cli_type;
    pvt->cli_version = cli_version;
    pvt->cli_name = talloc_strdup(pvt, cli_name);
    if (!pvt->cli_name) return ENOMEM;
    pvt->cli_domain = talloc_strdup(pvt, cli_domain);
    if (!pvt->cli_domain) return ENOMEM;

    /* Create a hash table to handle queued update requests */
    ret = hash_create(10, &dp_requests, NULL);
    if (ret != HASH_SUCCESS) {
        fprintf(stderr, "cannot create hash table (%s)\n", hash_error_string(ret));
        talloc_zfree(pvt);
        return EIO;
    }

    sss_dp_conn_reconnect(pvt);

    return EOK;
}

struct nss_dp_req;

struct nss_dp_callback {
    struct nss_dp_callback *prev;
    struct nss_dp_callback *next;
    nss_dp_callback_t callback;
    struct nss_dp_req *ndp_req;
    void *callback_ctx;
};

struct nss_dp_req {
    struct tevent_context *ev;
    struct nss_dp_callback *cb_list;
    DBusPendingCall *pending_reply;

    char *key;
    dbus_uint16_t err_maj;
    dbus_uint32_t err_min;
    char *err_msg;
};

static int sss_dp_callback_destructor(void *ptr)
{
    struct nss_dp_callback *cb = talloc_get_type(ptr, struct nss_dp_callback);

    DLIST_REMOVE(cb->ndp_req->cb_list, cb);

    return EOK;
}

static int nss_dp_req_destructor(void *ptr)
{
    struct nss_dp_req *ndp_req = talloc_get_type(ptr, struct nss_dp_req);
    hash_key_t key;

    /* No callbacks to invoke. Destroy the hash entry */
    key.type = HASH_KEY_STRING;
    key.str = ndp_req->key;
    int hret = hash_delete(dp_requests, &key);
    if (hret != HASH_SUCCESS) {
        DEBUG(0, ("Could not clear entry from request queue\n"));
        /* This should never happen */
        return EIO;
    }
    return EOK;
}

static int nss_dp_get_reply(DBusPendingCall *pending,
                            dbus_uint16_t *err_maj,
                            dbus_uint32_t *err_min,
                            char **err_msg);

static void sss_dp_invoke_callback(struct tevent_context *ev,
                                   struct tevent_timer *te,
                                   struct timeval t, void *ptr)
{
    struct nss_dp_req *ndp_req;
    struct nss_dp_callback *cb;
    struct timeval tv;
    struct tevent_timer *tev;

    ndp_req = talloc_get_type(ptr, struct nss_dp_req);
    if (!ndp_req) {
        /* We didn't receive an nss_dp_req? */
        return;
    }

    cb = ndp_req->cb_list;
    cb->callback(ndp_req->err_maj,
                 ndp_req->err_min,
                 ndp_req->err_msg,
                 cb->callback_ctx);

    /* Free the callback memory and remove it from the list */
    talloc_zfree(cb);

    /* Call the next callback if needed */
    if (ndp_req->cb_list != NULL) {
        tv = tevent_timeval_current();
        tev = tevent_add_timer(ndp_req->ev, ndp_req, tv,
                              sss_dp_invoke_callback, ndp_req);
        if (!te) {
            /* Out of memory or other serious error */
            goto done;
        }

        return;
    }

    /* No more callbacks to invoke. Destroy the hash entry */
done:
    talloc_zfree(ndp_req);
}

static void nss_dp_send_acct_callback(DBusPendingCall *pending, void *ptr)
{
    int ret;
    struct nss_dp_req *ndp_req;
    struct nss_dp_callback *cb;
    struct timeval tv;
    struct tevent_timer *te;

    ndp_req = talloc_get_type(ptr, struct nss_dp_req);

    ret = nss_dp_get_reply(pending,
                           &ndp_req->err_maj,
                           &ndp_req->err_min,
                           &ndp_req->err_msg);
    if (ret != EOK) {
        if (ret == ETIME) {
            ndp_req->err_maj = DP_ERR_TIMEOUT;
            ndp_req->err_min = ret;
            ndp_req->err_msg = talloc_strdup(ndp_req, "Request timed out");
        }
        else {
            ndp_req->err_maj = DP_ERR_FATAL;
            ndp_req->err_min = ret;
            ndp_req->err_msg =
                talloc_strdup(ndp_req,
                              "Failed to get reply from Data Provider");
        }
    }

    /* Check whether we need to issue any callbacks */
    cb = ndp_req->cb_list;
    if (ndp_req->cb_list == NULL) {
        if (cb == NULL) {
            /* No callbacks to invoke. Destroy the hash entry */
            talloc_zfree(ndp_req);
            return;
        }
    }

    /* Queue up all callbacks */
    tv = tevent_timeval_current();
    te = tevent_add_timer(ndp_req->ev, ndp_req, tv,
                          sss_dp_invoke_callback, ndp_req);
    if (!te) {
        /* Out of memory or other serious error */
        goto error;
    }

    return;

error:
    talloc_zfree(ndp_req);
}

static int nss_dp_send_acct_req_create(struct resp_ctx *rctx,
                                       TALLOC_CTX *memctx,
                                       const char *domain,
                                       uint32_t be_type,
                                       char *filter,
                                       int timeout,
                                       nss_dp_callback_t callback,
                                       void *callback_ctx,
                                       struct nss_dp_req **ndp);

int nss_dp_send_acct_req(struct resp_ctx *rctx, TALLOC_CTX *memctx,
                         nss_dp_callback_t callback, void *callback_ctx,
                         int timeout, const char *domain, int type,
                         const char *opt_name, uint32_t opt_id)
{
    int ret, hret;
    uint32_t be_type;
    char *filter;
    hash_key_t key;
    hash_value_t value;
    TALLOC_CTX *tmp_ctx;
    struct nss_dp_req *ndp_req;
    struct nss_dp_callback *cb;

    /* either, or, not both */
    if (opt_name && opt_id) {
        return EINVAL;
    }

    if (!domain) {
        return EINVAL;
    }

    tmp_ctx = talloc_new(NULL);
    if (!tmp_ctx) {
        return ENOMEM;
    }

    switch (type) {
    case NSS_DP_USER:
        be_type = BE_REQ_USER;
        break;
    case NSS_DP_GROUP:
        be_type = BE_REQ_GROUP;
        break;
    case NSS_DP_INITGROUPS:
        be_type = BE_REQ_INITGROUPS;
        break;
    default:
        return EINVAL;
    }

    key.type = HASH_KEY_STRING;
    key.str = NULL;

    if (opt_name) {
        filter = talloc_asprintf(tmp_ctx, "name=%s", opt_name);
        key.str = talloc_asprintf(tmp_ctx, "%d%s@%s", type, opt_name, domain);
    } else if (opt_id) {
        filter = talloc_asprintf(tmp_ctx, "idnumber=%u", opt_id);
        key.str = talloc_asprintf(tmp_ctx, "%d%d@%s", type, opt_id, domain);
    } else {
        filter = talloc_strdup(tmp_ctx, "name=*");
        key.str = talloc_asprintf(tmp_ctx, "%d*@%s", type, domain);
    }
    if (!filter || !key.str) {
        talloc_zfree(tmp_ctx);
        return ENOMEM;
    }

    /* Check whether there's already a request in progress */
    hret = hash_lookup(dp_requests, &key, &value);
    switch (hret) {
    case HASH_SUCCESS:
        /* Request already in progress
         * Add an additional callback if needed and return
         */
        DEBUG(2, ("Identical request in progress\n"));
        if (callback) {
            /* We have a new request asking for a callback */
            ndp_req = talloc_get_type(value.ptr, struct nss_dp_req);
            if (!ndp_req) {
                DEBUG(0, ("Could not retrieve DP request context\n"));
                ret = EIO;
                goto done;
            }

            cb = talloc_zero(memctx, struct nss_dp_callback);
            if (!cb) {
                ret = ENOMEM;
                goto done;
            }

            cb->callback = callback;
            cb->callback_ctx = callback_ctx;
            cb->ndp_req = ndp_req;

            DLIST_ADD_END(ndp_req->cb_list, cb, struct nss_dp_callback *);
            talloc_set_destructor((TALLOC_CTX *)cb, sss_dp_callback_destructor);
        }
        ret = EOK;
        goto done;

    case HASH_ERROR_KEY_NOT_FOUND:
        /* No such request in progress
         * Create a new request
         */
        ret = nss_dp_send_acct_req_create(rctx, memctx, domain,
                                          be_type, filter, timeout,
                                          callback, callback_ctx,
                                          &ndp_req);
        if (ret == EOK) {
            value.type = HASH_VALUE_PTR;
            value.ptr = ndp_req;
            hret = hash_enter(dp_requests, &key, &value);
            if (hret != HASH_SUCCESS) {
                DEBUG(0, ("Could not store request query (%s)",
                          hash_error_string(hret)));
                ret = EIO;
                goto done;
            }

            ndp_req->key = talloc_strdup(ndp_req, key.str);
            talloc_set_destructor((TALLOC_CTX *)ndp_req, nss_dp_req_destructor);
        }
        break;

    default:
        DEBUG(0,("Could not query request list (%s)\n",
                  hash_error_string(hret)));
        ret = EIO;
        goto done;
    }

    ret = EOK;

done:
    talloc_zfree(tmp_ctx);
    return ret;
}

static int nss_dp_send_acct_req_create(struct resp_ctx *rctx,
                                       TALLOC_CTX *memctx,
                                       const char *domain,
                                       uint32_t be_type,
                                       char *filter,
                                       int timeout,
                                       nss_dp_callback_t callback,
                                       void *callback_ctx,
                                       struct nss_dp_req **ndp)
{
    DBusConnection *dbus_conn;
    DBusMessage *msg;
    DBusPendingCall *pending_reply;
    dbus_bool_t dbret;
    struct nss_dp_callback *cb;
    struct nss_dp_req *ndp_req;

    const char *attrs = "core";

    /* double check dp_ctx has actually been initialized.
     * in some pathological cases it may happen that nss starts up before
     * dp connection code is actually able to establish a connection.
     */
    if (!rctx->dp_conn) {
        DEBUG(1, ("The Data Provider connection is not available yet!"
                  " This maybe a bug, it shouldn't happen!\n"));
        return EIO;
    }
    dbus_conn = sbus_get_connection(rctx->dp_conn);

    /* create the message */
    msg = dbus_message_new_method_call(NULL,
                                       DP_CLI_PATH,
                                       DP_CLI_INTERFACE,
                                       DP_SRV_METHOD_GETACCTINFO);
    if (msg == NULL) {
        DEBUG(0,("Out of memory?!\n"));
        return ENOMEM;
    }

    DEBUG(4, ("Sending request for [%s][%u][%s][%s]\n",
              domain, be_type, attrs, filter));

    dbret = dbus_message_append_args(msg,
                                     DBUS_TYPE_STRING, &domain,
                                     DBUS_TYPE_UINT32, &be_type,
                                     DBUS_TYPE_STRING, &attrs,
                                     DBUS_TYPE_STRING, &filter,
                                     DBUS_TYPE_INVALID);
    if (!dbret) {
        DEBUG(1,("Failed to build message\n"));
        return EIO;
    }

    dbret = dbus_connection_send_with_reply(dbus_conn, msg,
                                            &pending_reply, timeout);
    if (!dbret || pending_reply == NULL) {
        /*
         * Critical Failure
         * We can't communicate on this connection
         * We'll drop it using the default destructor.
         */
        DEBUG(0, ("D-BUS send failed.\n"));
        dbus_message_unref(msg);
        return EIO;
    }

    ndp_req = talloc_zero(NULL, struct nss_dp_req);
    if (!ndp_req) {
        dbus_message_unref(msg);
        return ENOMEM;
    }

    ndp_req->ev = rctx->ev;

    if (callback) {
        cb = talloc_zero(memctx, struct nss_dp_callback);
        if (!cb) {
            dbus_message_unref(msg);
            talloc_zfree(ndp_req);
            return ENOMEM;
        }
        cb->callback = callback;
        cb->callback_ctx = callback_ctx;
        cb->ndp_req = ndp_req;

        DLIST_ADD(ndp_req->cb_list, cb);
        talloc_set_destructor((TALLOC_CTX *)cb, sss_dp_callback_destructor);
    }

    /* Set up the reply handler */
    dbret = dbus_pending_call_set_notify(pending_reply,
                                         nss_dp_send_acct_callback,
                                         ndp_req, NULL);
    if (!dbret) {
        DEBUG(0, ("Could not queue up pending request!"));
        talloc_zfree(ndp_req);
        dbus_pending_call_cancel(pending_reply);
        dbus_message_unref(msg);
        return EIO;
    }

    dbus_message_unref(msg);

    *ndp = ndp_req;

    return EOK;
}

static int nss_dp_get_reply(DBusPendingCall *pending,
                            dbus_uint16_t *err_maj,
                            dbus_uint32_t *err_min,
                            char **err_msg)
{
    DBusMessage *reply;
    DBusError dbus_error;
    dbus_bool_t ret;
    int type;
    int err = EOK;

    dbus_error_init(&dbus_error);

    reply = dbus_pending_call_steal_reply(pending);
    if (!reply) {
        /* reply should never be null. This function shouldn't be called
         * until reply is valid or timeout has occurred. If reply is NULL
         * here, something is seriously wrong and we should bail out.
         */
        DEBUG(0, ("Severe error. A reply callback was called but no reply was received and no timeout occurred\n"));

        /* FIXME: Destroy this connection ? */
        err = EIO;
        goto done;
    }

    type = dbus_message_get_type(reply);
    switch (type) {
    case DBUS_MESSAGE_TYPE_METHOD_RETURN:
        ret = dbus_message_get_args(reply, &dbus_error,
                                    DBUS_TYPE_UINT16, err_maj,
                                    DBUS_TYPE_UINT32, err_min,
                                    DBUS_TYPE_STRING, err_msg,
                                    DBUS_TYPE_INVALID);
        if (!ret) {
            DEBUG(1,("Failed to parse message\n"));
            /* FIXME: Destroy this connection ? */
            if (dbus_error_is_set(&dbus_error)) dbus_error_free(&dbus_error);
            err = EIO;
            goto done;
        }

        DEBUG(4, ("Got reply (%u, %u, %s) from Data Provider\n",
                  (unsigned int)*err_maj, (unsigned int)*err_min, *err_msg));

        break;

    case DBUS_MESSAGE_TYPE_ERROR:
        if (strcmp(dbus_message_get_error_name(reply),
                   DBUS_ERROR_NO_REPLY) == 0) {
            err = ETIME;
            goto done;
        }
        DEBUG(0,("The Data Provider returned an error [%s]\n",
                 dbus_message_get_error_name(reply)));
        /* Falling through to default intentionally*/
    default:
        /*
         * Timeout or other error occurred or something
         * unexpected happened.
         * It doesn't matter which, because either way we
         * know that this connection isn't trustworthy.
         * We'll destroy it now.
         */

        /* FIXME: Destroy this connection ? */
        err = EIO;
    }

done:
    dbus_pending_call_unref(pending);
    dbus_message_unref(reply);

    return err;
}