// This Source Code Form is subject to the terms of the Mozilla Public
// License, version 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

#include <stdlib.h>
#include <stdint.h>
#include <time.h>
#include <math.h>
#include <limits.h>
#include <gcrypt.h>
#include <signal_protocol.h>
#include <key_helper.h>
#include <session_builder.h>
#include <session_cipher.h>
#include <protocol.h>
#include <curve.h>
#include <lmdb.h>
#include <strophe.h>
#include <weechat/weechat-plugin.h>

struct t_omemo_db {
    MDB_env *env;
    MDB_dbi dbi_omemo;
};

#include "plugin.h"
#include "xmpp/stanza.h"
#include "account.h"
#include "omemo.h"
#include "util.h"

#define mdb_val_str(s) { \
    .mv_data = s, .mv_size = strlen(s), \
}

#define mdb_val_intptr(i) { \
    .mv_data = i, .mv_size = sizeof(*i), \
}

#define mdb_val_sizeof(t) { \
    .mv_data = NULL, .mv_size = sizeof(t), \
}

#define PRE_KEY_START 1
#define PRE_KEY_COUNT 100

#define AES_KEY_SIZE (16)
#define AES_IV_SIZE (12)

const char *OMEMO_ADVICE = "[OMEMO encrypted message (XEP-0384)]";

size_t base64_decode(const char *buffer, size_t length, uint8_t **result)
{
    *result = malloc(sizeof(uint8_t) * length);
    return weechat_string_base_decode(64, buffer, (char*)*result);
}

size_t base64_encode(const uint8_t *buffer, size_t length, char **result)
{
    *result = malloc(sizeof(char) * (length * 2));
    return weechat_string_base_encode(64, (char*)buffer, length, *result);
}

int aes_decrypt(const uint8_t *ciphertext, size_t ciphertext_len,
                uint8_t *key, uint8_t *iv, uint8_t *tag, size_t tag_len,
                uint8_t **plaintext, size_t *plaintext_len)
{
    gcry_cipher_hd_t cipher = NULL;
    if (gcry_cipher_open(&cipher, GCRY_CIPHER_AES192,
                GCRY_CIPHER_MODE_GCM, GCRY_CIPHER_SECURE)) goto cleanup;
    if (gcry_cipher_setkey(cipher, key, AES_KEY_SIZE)) goto cleanup;
    if (gcry_cipher_setiv(cipher, iv, AES_IV_SIZE)) goto cleanup;
    *plaintext_len = ciphertext_len;
    *plaintext = malloc((sizeof(uint8_t) * *plaintext_len) + 1);
    if (gcry_cipher_decrypt(cipher, *plaintext, *plaintext_len,
                ciphertext, ciphertext_len)) goto cleanup;
    if (gcry_cipher_checktag(cipher, tag, tag_len)) goto cleanup;
    return 1;
cleanup:
    gcry_cipher_close(cipher);
    return 0;
}

int aes_encrypt(const uint8_t *plaintext, size_t plaintext_len,
                uint8_t **key, uint8_t **iv, uint8_t **tag, size_t *tag_len,
                uint8_t **ciphertext, size_t *ciphertext_len)
{
    *tag_len = 16;
    *tag = gcry_random_bytes(*tag_len, GCRY_STRONG_RANDOM);
    *iv = gcry_random_bytes(AES_IV_SIZE, GCRY_STRONG_RANDOM);
    *key = gcry_random_bytes(AES_KEY_SIZE + *tag_len, GCRY_STRONG_RANDOM);

    gcry_cipher_hd_t cipher = NULL;
    if (gcry_cipher_open(&cipher, GCRY_CIPHER_AES192,
                GCRY_CIPHER_MODE_GCM, GCRY_CIPHER_SECURE)) goto cleanup;
    if (gcry_cipher_setkey(cipher, key, AES_KEY_SIZE)) goto cleanup;
    if (gcry_cipher_setiv(cipher, iv, AES_IV_SIZE)) goto cleanup;
    *ciphertext_len = plaintext_len;
    *ciphertext = malloc((sizeof(uint8_t) * *ciphertext_len) + 1);
    if (gcry_cipher_encrypt(cipher, *ciphertext, *ciphertext_len,
                plaintext, plaintext_len)) goto cleanup;
    if (gcry_cipher_gettag(cipher, *tag, *tag_len)) goto cleanup;
    return 1;
cleanup:
    gcry_cipher_close(cipher);
    return 0;
}

void signal_protocol_address_free(signal_protocol_address* ptr) {
    if (!ptr)
        return;
    if (ptr->name) {
        free((void*)ptr->name);
    }
    return free(ptr);
}

void signal_protocol_address_set_name(signal_protocol_address* self, const char* name) {
    if (!self)
        return;
    if (!name)
        return;
    char* n = malloc(strlen(name)+1);
    memcpy(n, name, strlen(name));
    n[strlen(name)] = 0;
    if (self->name) {
        free((void*)self->name);
    }
    self->name = n;
    self->name_len = strlen(n);
}

char* signal_protocol_address_get_name(signal_protocol_address* self) {
    if (!self)
        return NULL;
    if (!self->name)
        return 0;
    char* res = malloc(sizeof(char) * (self->name_len + 1));
    memcpy(res, self->name, self->name_len);
    res[self->name_len] = 0;
    return res;
}

int32_t signal_protocol_address_get_device_id(signal_protocol_address* self) {
    if (!self)
        return -1;
    return self->device_id;
}

void signal_protocol_address_set_device_id(signal_protocol_address* self, int32_t device_id) {
    if (!self)
        return;
    self->device_id = device_id;
}

signal_protocol_address* signal_protocol_address_new(const char* name, int32_t device_id) {
    if (!name)
        return NULL;
    signal_protocol_address* address = malloc(sizeof(signal_protocol_address));
    address->device_id = -1;
    address->name = NULL;
    signal_protocol_address_set_name(address, name);
    signal_protocol_address_set_device_id(address, device_id);
    return address;
}

int aes_cipher(int cipher, size_t key_len, int* algo, int* mode) {
    switch (key_len) {
        case 16:
            *algo = GCRY_CIPHER_AES128;
            break;
        case 24:
            *algo = GCRY_CIPHER_AES192;
            break;
        case 32:
            *algo = GCRY_CIPHER_AES256;
            break;
        default:
            return SG_ERR_UNKNOWN;
    }
    switch (cipher) {
        case SG_CIPHER_AES_CBC_PKCS5:
            *mode = GCRY_CIPHER_MODE_CBC;
            break;
        case SG_CIPHER_AES_CTR_NOPADDING:
            *mode = GCRY_CIPHER_MODE_CTR;
            break;
        default:
            return SG_ERR_UNKNOWN;
    }
    return SG_SUCCESS;
}

void lock_function(void *user_data)
{
    (void) user_data;
}

void unlock_function(void *user_data)
{
    (void) user_data;
}

int cp_randomize(uint8_t *data, size_t len) {
    gcry_randomize(data, len, GCRY_STRONG_RANDOM);
    return SG_SUCCESS;
}

int cp_random_generator(uint8_t *data, size_t len, void *user_data) {
    (void) user_data;

    gcry_randomize(data, len, GCRY_STRONG_RANDOM);
    return SG_SUCCESS;
}

int cp_hmac_sha256_init(void **hmac_context, const uint8_t *key, size_t key_len, void *user_data) {
    (void) user_data;

    gcry_mac_hd_t* ctx = malloc(sizeof(gcry_mac_hd_t));
    if (!ctx) return SG_ERR_NOMEM;

    if (gcry_mac_open(ctx, GCRY_MAC_HMAC_SHA256, 0, 0)) {
        free(ctx);
        return SG_ERR_UNKNOWN;
    }

    if (gcry_mac_setkey(*ctx, key, key_len)) {
        free(ctx);
        return SG_ERR_UNKNOWN;
    }

    *hmac_context = ctx;

    return SG_SUCCESS;
}

int cp_hmac_sha256_update(void *hmac_context, const uint8_t *data, size_t data_len, void *user_data) {
    (void) user_data;

    gcry_mac_hd_t* ctx = hmac_context;

    if (gcry_mac_write(*ctx, data, data_len)) return SG_ERR_UNKNOWN;

    return SG_SUCCESS;
}

int cp_hmac_sha256_final(void *hmac_context, signal_buffer **output, void *user_data) {
    (void) user_data;

    size_t len = gcry_mac_get_algo_maclen(GCRY_MAC_HMAC_SHA256);
    uint8_t md[len];
    gcry_mac_hd_t* ctx = hmac_context;

    if (gcry_mac_read(*ctx, md, &len)) return SG_ERR_UNKNOWN;

    signal_buffer *output_buffer = signal_buffer_create(md, len);
    if (!output_buffer) return SG_ERR_NOMEM;

    *output = output_buffer;

    return SG_SUCCESS;
}

void cp_hmac_sha256_cleanup(void *hmac_context, void *user_data) {
    (void) user_data;

    gcry_mac_hd_t* ctx = hmac_context;
    if (ctx) {
        gcry_mac_close(*ctx);
        free(ctx);
    }
}

int cp_sha512_digest_init(void **digest_context, void *user_data) {
    (void) user_data;

    gcry_md_hd_t* ctx = malloc(sizeof(gcry_mac_hd_t));
    if (!ctx) return SG_ERR_NOMEM;

    if (gcry_md_open(ctx, GCRY_MD_SHA512, 0)) {
        free(ctx);
        return SG_ERR_UNKNOWN;
    }

    *digest_context = ctx;

    return SG_SUCCESS;
}

int cp_sha512_digest_update(void *digest_context, const uint8_t *data, size_t data_len, void *user_data) {
    (void) user_data;

    gcry_md_hd_t* ctx = digest_context;

    gcry_md_write(*ctx, data, data_len);

    return SG_SUCCESS;
}

int cp_sha512_digest_final(void *digest_context, signal_buffer **output, void *user_data) {
    (void) user_data;

    size_t len = gcry_md_get_algo_dlen(GCRY_MD_SHA512);
    gcry_md_hd_t* ctx = digest_context;

    uint8_t* md = gcry_md_read(*ctx, GCRY_MD_SHA512);
    if (!md) return SG_ERR_UNKNOWN;

    gcry_md_reset(*ctx);

    signal_buffer *output_buffer = signal_buffer_create(md, len);
    free(md);
    if (!output_buffer) return SG_ERR_NOMEM;

    *output = output_buffer;

    return SG_SUCCESS;
}

void cp_sha512_digest_cleanup(void *digest_context, void *user_data) {
    (void) user_data;

    gcry_md_hd_t* ctx = digest_context;
    if (ctx) {
        gcry_md_close(*ctx);
        free(ctx);
    }
}

int cp_encrypt(signal_buffer **output,
        int cipher,
        const uint8_t *key, size_t key_len,
        const uint8_t *iv, size_t iv_len,
        const uint8_t *plaintext, size_t plaintext_len,
        void *user_data) {
    (void) user_data;

    int algo, mode, error_code = SG_ERR_UNKNOWN;
    if (aes_cipher(cipher, key_len, &algo, &mode)) return SG_ERR_INVAL;

    gcry_cipher_hd_t ctx = {0};

    if (gcry_cipher_open(&ctx, algo, mode, 0)) return SG_ERR_NOMEM;

    signal_buffer* padded = 0;
    signal_buffer* out_buf = 0;
    goto no_error;
error:
    gcry_cipher_close(ctx);
    if (padded != 0) {
        signal_buffer_bzero_free(padded);
    }
    if (out_buf != 0) {
        signal_buffer_free(out_buf);
    }
    return error_code;
no_error:

    if (gcry_cipher_setkey(ctx, key, key_len)) goto error;

    uint8_t tag_len = 0, pad_len = 0;
    switch (cipher) {
        case SG_CIPHER_AES_CBC_PKCS5:
            if (gcry_cipher_setiv(ctx, iv, iv_len)) goto error;
            pad_len = 16 - (plaintext_len % 16);
            if (pad_len == 0) pad_len = 16;
            break;
        case SG_CIPHER_AES_CTR_NOPADDING:
            if (gcry_cipher_setctr(ctx, iv, iv_len)) goto error;
            break;
        default:
            return SG_ERR_UNKNOWN;
    }

    size_t padded_len = plaintext_len + pad_len;
    padded = signal_buffer_alloc(padded_len);
    if (padded == 0) {
        error_code = SG_ERR_NOMEM;
        goto error;
    }

    memset(signal_buffer_data(padded) + plaintext_len, pad_len, pad_len);
    memcpy(signal_buffer_data(padded), plaintext, plaintext_len);

    out_buf = signal_buffer_alloc(padded_len + tag_len);
    if (out_buf == 0) {
        error_code = SG_ERR_NOMEM;
        goto error;
    }

    if (gcry_cipher_encrypt(ctx, signal_buffer_data(out_buf), padded_len, signal_buffer_data(padded), padded_len)) goto error;

    if (tag_len > 0) {
        if (gcry_cipher_gettag(ctx, signal_buffer_data(out_buf) + padded_len, tag_len)) goto error;
    }

    *output = out_buf;
    out_buf = 0;

    signal_buffer_bzero_free(padded);
    padded = 0;

    gcry_cipher_close(ctx);
    return SG_SUCCESS;
}

int cp_decrypt(signal_buffer **output,
        int cipher,
        const uint8_t *key, size_t key_len,
        const uint8_t *iv, size_t iv_len,
        const uint8_t *ciphertext, size_t ciphertext_len,
        void *user_data) {
    (void) user_data;

    int algo, mode, error_code = SG_ERR_UNKNOWN;
    *output = 0;
    if (aes_cipher(cipher, key_len, &algo, &mode)) return SG_ERR_INVAL;
    if (ciphertext_len == 0) return SG_ERR_INVAL;

    gcry_cipher_hd_t ctx = {0};

    if (gcry_cipher_open(&ctx, algo, mode, 0)) return SG_ERR_NOMEM;

    signal_buffer* out_buf = 0;
    goto no_error;
error:
    gcry_cipher_close(ctx);
    if (out_buf != 0) {
        signal_buffer_bzero_free(out_buf);
    }
    return error_code;
no_error:

    if (gcry_cipher_setkey(ctx, key, key_len)) goto error;

    uint8_t tag_len = 0, pkcs_pad = 0;
    switch (cipher) {
        case SG_CIPHER_AES_CBC_PKCS5:
            if (gcry_cipher_setiv(ctx, iv, iv_len)) goto error;
            pkcs_pad = 1;
            break;
        case SG_CIPHER_AES_CTR_NOPADDING:
            if (gcry_cipher_setctr(ctx, iv, iv_len)) goto error;
            break;
        default:
            goto error;
    }

    size_t padded_len = ciphertext_len - tag_len;
    out_buf = signal_buffer_alloc(padded_len);
    if (out_buf == 0) {
        error_code = SG_ERR_NOMEM;
        goto error;
    }

    if (gcry_cipher_decrypt(ctx, signal_buffer_data(out_buf), signal_buffer_len(out_buf), ciphertext, padded_len)) goto error;

    if (tag_len > 0) {
        if (gcry_cipher_checktag(ctx, ciphertext + padded_len, tag_len)) goto error;
    }

    if (pkcs_pad) {
        uint8_t pad_len = signal_buffer_data(out_buf)[padded_len - 1];
        if (pad_len > 16 || pad_len > padded_len) goto error;
        *output = signal_buffer_create(signal_buffer_data(out_buf), padded_len - pad_len);
        signal_buffer_bzero_free(out_buf);
        out_buf = 0;
    } else {
        *output = out_buf;
        out_buf = 0;
    }

    gcry_cipher_close(ctx);
    return SG_SUCCESS;
}

int iks_get_identity_key_pair(signal_buffer **public_data, signal_buffer **private_data, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_local_private_key = mdb_val_str("local_private_key");
    MDB_val k_local_public_key = mdb_val_str("local_public_key");
    MDB_val v_local_private_key, v_local_public_key;

    if (mdb_txn_begin(omemo->db->env, NULL, 0, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        goto cleanup;
    }

    if (!mdb_get(transaction, omemo->db->dbi_omemo,
                 &k_local_private_key, &v_local_private_key) &&
        !mdb_get(transaction, omemo->db->dbi_omemo,
                 &k_local_public_key, &v_local_public_key))
    {
        *private_data = signal_buffer_create(v_local_private_key.mv_data, v_local_private_key.mv_size);
        *public_data = signal_buffer_create(v_local_public_key.mv_data, v_local_public_key.mv_size);

        if (mdb_txn_commit(transaction)) {
            weechat_printf(NULL, "%sxmpp: failed to write lmdb transaction",
                           weechat_prefix("error"));
            goto cleanup;
        };
    }
    else
    {
        struct ratchet_identity_key_pair *identity;

        signal_protocol_key_helper_generate_identity_key_pair(
            &identity, omemo->context);
        ec_private_key *private_key = ratchet_identity_key_pair_get_private(identity);
        ec_public_key *public_key = ratchet_identity_key_pair_get_public(identity);

        ec_private_key_serialize(private_data, private_key);
        ec_public_key_serialize(public_data, public_key);

        v_local_private_key.mv_data = signal_buffer_data(*private_data);
        v_local_private_key.mv_size = signal_buffer_len(*private_data);
        v_local_public_key.mv_data = signal_buffer_data(*public_data);
        v_local_public_key.mv_size = signal_buffer_len(*public_data);

        if (mdb_put(transaction, omemo->db->dbi_omemo,
                    &k_local_private_key, &v_local_private_key, MDB_NOOVERWRITE) &&
            mdb_put(transaction, omemo->db->dbi_omemo,
                    &k_local_public_key, &v_local_public_key, MDB_NOOVERWRITE))
        {
            weechat_printf(NULL, "%sxmpp: failed to write lmdb value",
                           weechat_prefix("error"));
            goto cleanup;
        };

        if (mdb_txn_commit(transaction)) {
            weechat_printf(NULL, "%sxmpp: failed to write lmdb transaction",
                           weechat_prefix("error"));
            goto cleanup;
        };

        *private_data = signal_buffer_create(v_local_private_key.mv_data,
                v_local_private_key.mv_size);
        *public_data = signal_buffer_create(v_local_public_key.mv_data,
                v_local_public_key.mv_size);
    }

    return 0;
cleanup:
    mdb_txn_abort(transaction);
    return -1;
}

int iks_get_local_registration_id(void *user_data, uint32_t *registration_id)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_local_registration_id = mdb_val_str("local_registration_id");
    MDB_val v_local_registration_id = mdb_val_sizeof(uint32_t);

    // Return the local client's registration ID
    if (mdb_txn_begin(omemo->db->env, NULL, 0, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        goto cleanup;
    }

    if (!mdb_get(transaction, omemo->db->dbi_omemo,
                 &k_local_registration_id,
                 &v_local_registration_id))
    {
        *registration_id = *(uint32_t*)v_local_registration_id.mv_data;

        if (mdb_txn_commit(transaction)) {
            weechat_printf(NULL, "%sxmpp: failed to read lmdb transaction",
                           weechat_prefix("error"));
            goto cleanup;
        };
    }
    else
    {
        uint32_t generated_id;
        signal_protocol_key_helper_generate_registration_id(
            &generated_id, 0, omemo->context);
        v_local_registration_id.mv_data = &generated_id;

        if (mdb_put(transaction, omemo->db->dbi_omemo,
                    &k_local_registration_id,
                    &v_local_registration_id, MDB_NOOVERWRITE))
        {
            weechat_printf(NULL, "%sxmpp: failed to write lmdb value",
                           weechat_prefix("error"));
            goto cleanup;
        };

        if (mdb_txn_commit(transaction)) {
            weechat_printf(NULL, "%sxmpp: failed to write lmdb transaction",
                           weechat_prefix("error"));
            goto cleanup;
        };

        *registration_id = generated_id;
    }

    return 0;
cleanup:
    mdb_txn_abort(transaction);
    return -1;
}

int iks_save_identity(const signal_protocol_address *address, uint8_t *key_data, size_t key_len, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_registration_id = {
        .mv_data = NULL,
        .mv_size = strlen("registration_id_") + address->name_len,
    };
    MDB_val v_registration_id = mdb_val_intptr((uint32_t*)&address->device_id);
    MDB_val k_identity_key = {
        .mv_data = NULL,
        .mv_size = strlen("identity_key_") + address->name_len,
    };
    MDB_val v_identity_key = {.mv_data = key_data, .mv_size = key_len};

    k_registration_id.mv_data = malloc(sizeof(char) * (
                                           k_registration_id.mv_size + 1));
    snprintf(k_registration_id.mv_data, k_registration_id.mv_size,
             "registration_id_%s", address->name);
    k_identity_key.mv_data = malloc(sizeof(char) * (
                                           k_identity_key.mv_size + 1));
    snprintf(k_identity_key.mv_data, k_identity_key.mv_size,
             "identity_key_%s", address->name);

    if (mdb_txn_begin(omemo->db->env, NULL, 0, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        return -1;
    }

    if (mdb_put(transaction, omemo->db->dbi_omemo, &k_registration_id,
                &v_registration_id, 0) ||
        mdb_put(transaction, omemo->db->dbi_omemo, &k_identity_key,
                &v_identity_key, 0)) {
      weechat_printf(NULL, "%sxmpp: failed to write lmdb value",
                     weechat_prefix("error"));
      return -1;
    };

    if (mdb_txn_commit(transaction)) {
      weechat_printf(NULL, "%sxmpp: failed to write lmdb transaction",
                     weechat_prefix("error"));
      return -1;
    };

    return 0;
}

int iks_is_trusted_identity(const signal_protocol_address *address, uint8_t *key_data, size_t key_len, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_registration_id = {
        .mv_data = NULL,
        .mv_size = strlen("registration_id_") + address->name_len,
    };
    MDB_val v_registration_id = mdb_val_intptr((uint32_t*)&address->device_id);
    MDB_val k_identity_key = {
        .mv_data = NULL,
        .mv_size = strlen("identity_key_") + address->name_len,
    };
    MDB_val v_identity_key = {.mv_data = key_data, .mv_size = key_len};
    int trusted = 1;

    k_registration_id.mv_data = malloc(sizeof(char) * (
                                           k_registration_id.mv_size + 1));
    snprintf(k_registration_id.mv_data, k_registration_id.mv_size,
             "registration_id_%s", address->name);
    k_identity_key.mv_data = malloc(sizeof(char) * (
                                           k_identity_key.mv_size + 1));
    snprintf(k_identity_key.mv_data, k_identity_key.mv_size,
             "identity_key_%s", address->name);

    if (mdb_txn_begin(omemo->db->env, NULL, MDB_RDONLY, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        return -1;
    }

    if (mdb_get(transaction, omemo->db->dbi_omemo, &k_registration_id,
                &v_registration_id) ||
        mdb_get(transaction, omemo->db->dbi_omemo, &k_identity_key,
                &v_identity_key)) {
      weechat_printf(NULL, "%sxmpp: failed to read lmdb value",
                     weechat_prefix("error"));
      return -1;
    };

    if (*(uint32_t*)v_registration_id.mv_data != (uint32_t)address->device_id)
        trusted = 0;
    if (v_identity_key.mv_size != key_len ||
        memcmp(v_identity_key.mv_data, key_data, key_len) != 0)
        trusted = 0;

    if (mdb_txn_commit(transaction)) {
      weechat_printf(NULL, "%sxmpp: failed to write lmdb transaction",
                     weechat_prefix("error"));
      return -1;
    };

    return trusted;
}

void iks_destroy_func(void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    (void) omemo;
    // Function called to perform cleanup when the data store context is being destroyed
}

int pks_store_pre_key(uint32_t pre_key_id, uint8_t *record, size_t record_len, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_pre_key = {
        .mv_data = NULL,
        .mv_size = strlen("pre_key_") + 10, // strlen(UINT32_MAX)
    };
    MDB_val v_pre_key = {.mv_data = record, .mv_size = record_len};

    k_pre_key.mv_data = malloc(sizeof(char) * (
                                           k_pre_key.mv_size + 1));
    k_pre_key.mv_size =
    snprintf(k_pre_key.mv_data, k_pre_key.mv_size,
             "pre_key_%-10u", pre_key_id);

    if (mdb_txn_begin(omemo->db->env, NULL, 0, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        return -1;
    }

    if (mdb_put(transaction, omemo->db->dbi_omemo, &k_pre_key,
                &v_pre_key, 0)) {
      weechat_printf(NULL, "%sxmpp: failed to write lmdb value",
                     weechat_prefix("error"));
      return -1;
    };

    if (mdb_txn_commit(transaction)) {
      weechat_printf(NULL, "%sxmpp: failed to write lmdb transaction",
                     weechat_prefix("error"));
      return -1;
    };

    return 0;
}

int pks_contains_pre_key(uint32_t pre_key_id, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_pre_key = {
        .mv_data = NULL,
        .mv_size = strlen("pre_key_") + 10, // strlen(UINT32_MAX)
    };
    MDB_val v_pre_key;

    k_pre_key.mv_data = malloc(sizeof(char) * (
                                           k_pre_key.mv_size + 1));
    k_pre_key.mv_size =
    snprintf(k_pre_key.mv_data, k_pre_key.mv_size,
             "pre_key_%-10u", pre_key_id);

    if (mdb_txn_begin(omemo->db->env, NULL, MDB_RDONLY, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        return 0;
    }

    if (mdb_get(transaction, omemo->db->dbi_omemo, &k_pre_key,
                &v_pre_key)) {
        weechat_printf(NULL, "%sxmpp: failed to read lmdb value",
                       weechat_prefix("error"));
        mdb_txn_abort(transaction);
        return 0;
    };

    mdb_txn_abort(transaction);

    return 1;
}

uint32_t pks_get_count(struct t_omemo *omemo, int increment)
{
    uint32_t count = PRE_KEY_START;
    MDB_txn *transaction;
    MDB_val k_pre_key_idx = {
        .mv_data = "pre_key_idx",
        .mv_size = strlen("pre_key_idx"),
    };
    MDB_val v_pre_key_idx = mdb_val_intptr(&count);

    if (mdb_txn_begin(omemo->db->env, NULL, 0, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        goto cleanup;
    }

    if (!mdb_get(transaction, omemo->db->dbi_omemo,
                 &k_pre_key_idx, &v_pre_key_idx))
    {
        if (increment)
            count += PRE_KEY_COUNT;
    }

    if (mdb_put(transaction, omemo->db->dbi_omemo,
                &k_pre_key_idx, &v_pre_key_idx, 0))
    {
        weechat_printf(NULL, "%sxmpp: failed to read lmdb value",
                       weechat_prefix("error"));
        goto cleanup;
    };

    if (mdb_txn_commit(transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to write lmdb transaction",
                       weechat_prefix("error"));
        goto cleanup;
    };

    return count;
cleanup:
    mdb_txn_abort(transaction);
    return 0;
}

int pks_load_pre_key(signal_buffer **record, uint32_t pre_key_id, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_pre_key = {
        .mv_data = NULL,
        .mv_size = strlen("pre_key_") + 10, // strlen(UINT32_MAX)
    };
    MDB_val v_pre_key;

    k_pre_key.mv_data = malloc(sizeof(char) * (
                                           k_pre_key.mv_size + 1));
    k_pre_key.mv_size =
    snprintf(k_pre_key.mv_data, k_pre_key.mv_size,
             "pre_key_%-10u", pre_key_id);

    if (mdb_txn_begin(omemo->db->env, NULL, 0, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        goto cleanup;
    }

    if (!mdb_get(transaction, omemo->db->dbi_omemo,
                 &k_pre_key, &v_pre_key))
    {
        *record = signal_buffer_create(v_pre_key.mv_data, v_pre_key.mv_size);

        if (mdb_txn_commit(transaction)) {
            weechat_printf(NULL, "%sxmpp: failed to close lmdb transaction",
                           weechat_prefix("error"));
            goto cleanup;
        };
    }
    else
    {
        mdb_txn_abort(transaction);

        signal_protocol_key_helper_pre_key_list_node *pre_keys_list;
        session_pre_key *pre_key = NULL;

        for (signal_protocol_key_helper_generate_pre_keys(&pre_keys_list,
                    pks_get_count(omemo, 1), PRE_KEY_COUNT,
                    omemo->context); pre_keys_list;
             pre_keys_list = signal_protocol_key_helper_key_list_next(pre_keys_list))
        {
            pre_key = signal_protocol_key_helper_key_list_element(pre_keys_list);
            uint32_t id = session_pre_key_get_id(pre_key);
            session_pre_key_serialize(record, pre_key);
            pks_store_pre_key(id, signal_buffer_data(*record),
                    signal_buffer_len(*record), user_data);
        }
        signal_protocol_key_helper_key_list_free(pre_keys_list);
    }

    return 0;
cleanup:
    mdb_txn_abort(transaction);
    return -1;
}

int pks_remove_pre_key(uint32_t pre_key_id, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_pre_key = {
        .mv_data = NULL,
        .mv_size = strlen("pre_key_") + 10, // strlen(UINT32_MAX)
    };
    MDB_val v_pre_key;

    k_pre_key.mv_data = malloc(sizeof(char) * (
                                           k_pre_key.mv_size + 1));
    k_pre_key.mv_size =
    snprintf(k_pre_key.mv_data, k_pre_key.mv_size,
             "pre_key_%-10u", pre_key_id);

    if (mdb_txn_begin(omemo->db->env, NULL, 0, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        return -1;
    }

    if (mdb_del(transaction, omemo->db->dbi_omemo, &k_pre_key,
                &v_pre_key)) {
      weechat_printf(NULL, "%sxmpp: failed to erase lmdb value",
                     weechat_prefix("error"));
      return -1;
    };

    if (mdb_txn_commit(transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to close lmdb transaction",
                       weechat_prefix("error"));
        return -1;
    };

    return 0;
}

void pks_destroy_func(void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    (void) omemo;
    // Function called to perform cleanup when the data store context is being destroyed
}

int spks_load_signed_pre_key(signal_buffer **record, uint32_t signed_pre_key_id, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_signed_pre_key = {
        .mv_data = NULL,
        .mv_size = strlen("signed_pre_key_") + 10, // strlen(UINT32_MAX)
    };
    MDB_val v_signed_pre_key;

    k_signed_pre_key.mv_data = malloc(sizeof(char) * (
                                           k_signed_pre_key.mv_size + 1));
    k_signed_pre_key.mv_size =
    snprintf(k_signed_pre_key.mv_data, k_signed_pre_key.mv_size,
             "signed_pre_key_%-10u", signed_pre_key_id);

    if (mdb_txn_begin(omemo->db->env, NULL, 0, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        goto cleanup;
    }

    if (!mdb_get(transaction, omemo->db->dbi_omemo,
                 &k_signed_pre_key, &v_signed_pre_key))
    {
        *record = signal_buffer_create(v_signed_pre_key.mv_data, v_signed_pre_key.mv_size);

        if (mdb_txn_commit(transaction)) {
            weechat_printf(NULL, "%sxmpp: failed to close lmdb transaction",
                           weechat_prefix("error"));
            goto cleanup;
        };
    }
    else
    {
        session_signed_pre_key *signed_pre_key = NULL;
        signal_buffer *serialized_key = NULL;

        signal_protocol_key_helper_generate_signed_pre_key(&signed_pre_key, omemo->identity, signed_pre_key_id, time(NULL), omemo->context);
        session_signed_pre_key_serialize(&serialized_key, signed_pre_key);

        v_signed_pre_key.mv_data = signal_buffer_data(serialized_key);
        v_signed_pre_key.mv_size = signal_buffer_len(serialized_key);

        if (mdb_put(transaction, omemo->db->dbi_omemo,
                    &k_signed_pre_key, &v_signed_pre_key, MDB_NOOVERWRITE))
        {
            weechat_printf(NULL, "%sxmpp: failed to read lmdb value",
                           weechat_prefix("error"));
            goto cleanup;
        };

        if (mdb_txn_commit(transaction)) {
            weechat_printf(NULL, "%sxmpp: failed to write lmdb transaction",
                           weechat_prefix("error"));
            goto cleanup;
        };

        *record = serialized_key;
    }

    return 0;
cleanup:
    mdb_txn_abort(transaction);
    return -1;
}

int spks_store_signed_pre_key(uint32_t signed_pre_key_id, uint8_t *record, size_t record_len, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_signed_pre_key = {
        .mv_data = NULL,
        .mv_size = strlen("signed_pre_key_") + 10, // strlen(UINT32_MAX)
    };
    MDB_val v_signed_pre_key = {.mv_data = record, .mv_size = record_len};

    k_signed_pre_key.mv_data = malloc(sizeof(char) * (
                                           k_signed_pre_key.mv_size + 1));
    k_signed_pre_key.mv_size =
    snprintf(k_signed_pre_key.mv_data, k_signed_pre_key.mv_size,
             "signed_pre_key_%-10u", signed_pre_key_id);

    if (mdb_txn_begin(omemo->db->env, NULL, 0, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        return -1;
    }

    if (mdb_put(transaction, omemo->db->dbi_omemo, &k_signed_pre_key,
                &v_signed_pre_key, 0)) {
      weechat_printf(NULL, "%sxmpp: failed to write lmdb value",
                     weechat_prefix("error"));
      return -1;
    };

    if (mdb_txn_commit(transaction)) {
      weechat_printf(NULL, "%sxmpp: failed to write lmdb transaction",
                     weechat_prefix("error"));
      return -1;
    };

    return 0;
}

int spks_contains_signed_pre_key(uint32_t signed_pre_key_id, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_signed_pre_key = {
        .mv_data = NULL,
        .mv_size = strlen("signed_pre_key_") + 10, // strlen(UINT32_MAX)
    };
    MDB_val v_signed_pre_key;

    k_signed_pre_key.mv_data = malloc(sizeof(char) * (
                                           k_signed_pre_key.mv_size + 1));
    k_signed_pre_key.mv_size =
    snprintf(k_signed_pre_key.mv_data, k_signed_pre_key.mv_size,
             "signed_pre_key_%-10u", signed_pre_key_id);

    if (mdb_txn_begin(omemo->db->env, NULL, MDB_RDONLY, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        return 0;
    }

    if (mdb_get(transaction, omemo->db->dbi_omemo, &k_signed_pre_key,
                &v_signed_pre_key)) {
        mdb_txn_abort(transaction);
        return 0;
    };

    mdb_txn_abort(transaction);

    return 1;
}

int spks_remove_signed_pre_key(uint32_t signed_pre_key_id, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_signed_pre_key = {
        .mv_data = NULL,
        .mv_size = strlen("signed_pre_key_") + 10, // strlen(UINT32_MAX)
    };
    MDB_val v_signed_pre_key;

    k_signed_pre_key.mv_data = malloc(sizeof(char) * (
                                           k_signed_pre_key.mv_size + 1));
    k_signed_pre_key.mv_size =
    snprintf(k_signed_pre_key.mv_data, k_signed_pre_key.mv_size,
             "signed_pre_key_%-10u", signed_pre_key_id);

    if (mdb_txn_begin(omemo->db->env, NULL, 0, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        return -1;
    }

    if (mdb_del(transaction, omemo->db->dbi_omemo, &k_signed_pre_key,
                &v_signed_pre_key)) {
      weechat_printf(NULL, "%sxmpp: failed to erase lmdb value",
                     weechat_prefix("error"));
      return -1;
    };

    if (mdb_txn_commit(transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to close lmdb transaction",
                       weechat_prefix("error"));
        return -1;
    };

    return 0;
}

void spks_destroy_func(void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    (void) omemo;
    // Function called to perform cleanup when the data store context is being destroyed
}

int ss_load_session_func(signal_buffer **record, signal_buffer **user_record, const signal_protocol_address *address, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_session = {
        .mv_data = NULL,
        .mv_size = strlen("session_") + 10 + //strlen(address->device_id) +
             1 + strlen(address->name),
    };
    MDB_val v_session;
    MDB_val k_user = {
        .mv_data = NULL,
        .mv_size = strlen("user_") + 10 + //strlen(address->device_id) +
             1 + strlen(address->name),
    };
    MDB_val v_user;

    k_session.mv_data = malloc(sizeof(char) * (
                                           k_session.mv_size + 1));
    k_session.mv_size =
    snprintf(k_session.mv_data, k_session.mv_size,
             "session_%u_%s", address->device_id, address->name);
    k_user.mv_data = malloc(sizeof(char) * (
                                           k_user.mv_size + 1));
    k_user.mv_size =
    snprintf(k_user.mv_data, k_user.mv_size,
             "user_%u_%s", address->device_id, address->name);

    if (mdb_txn_begin(omemo->db->env, NULL, 0, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        goto cleanup;
    }

    if (!mdb_get(transaction, omemo->db->dbi_omemo,
                 &k_session, &v_session)/* &&
        !mdb_get(transaction, omemo->db->dbi_omemo,
                 &k_user, &v_user)*/)
    {
        *record = signal_buffer_create(v_session.mv_data, v_session.mv_size);
      //*user_record = signal_buffer_create(v_user.mv_data, v_user.mv_size);

        if (mdb_txn_commit(transaction)) {
            weechat_printf(NULL, "%sxmpp: failed to close lmdb transaction",
                           weechat_prefix("error"));
            goto cleanup;
        };
    }
    else
    {
        /*
        v_session.mv_data = signal_buffer_data(*record);
        v_session.mv_size = signal_buffer_len(*record);

        if (mdb_put(transaction, omemo->db->dbi_omemo,
                    &k_session, &v_session, MDB_NOOVERWRITE))
        {
            weechat_printf(NULL, "%sxmpp: failed to read lmdb value",
                           weechat_prefix("error"));
            goto cleanup;
        };

        if (mdb_txn_commit(transaction)) {
            weechat_printf(NULL, "%sxmpp: failed to write lmdb transaction",
                           weechat_prefix("error"));
            goto cleanup;
        };
        */
    }

    return 0;
cleanup:
    mdb_txn_abort(transaction);
    return -1;
}

int ss_get_sub_device_sessions_func(signal_int_list **sessions, const char *name, size_t name_len, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_device_ids = {
        .mv_data = NULL,
        .mv_size = strlen("device_ids_") + name_len,
    };
    MDB_val v_device_ids;

    k_device_ids.mv_data = malloc(sizeof(char) * (
                                           k_device_ids.mv_size + 1));
    snprintf(k_device_ids.mv_data, k_device_ids.mv_size,
             "device_ids_%s", name);

    if (mdb_txn_begin(omemo->db->env, NULL, MDB_RDONLY, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
    }

    if (!mdb_get(transaction, omemo->db->dbi_omemo,
                 &k_device_ids, &v_device_ids))
    {
        char **argv;
        int argc, i;
        signal_int_list *list = signal_int_list_alloc();

        if (!list) {
            mdb_txn_abort(transaction);
            return -1;
        }

        argv = weechat_string_split(v_device_ids.mv_data, " ", NULL, 0, 0, &argc);
        if (mdb_txn_commit(transaction)) {
            weechat_printf(NULL, "%sxmpp: failed to close lmdb transaction",
                           weechat_prefix("error"));
            return -1;
        };

        for (i = 0; i < argc; i++)
        {
            char* device_id = argv[i];

            signal_int_list_push_back(list, strtol(device_id, NULL, 10));
        }

        weechat_string_free_split(argv);

        *sessions = list;
        return argc;
    }
    else
    {
        mdb_txn_abort(transaction);
        return 0;
    }
}

int ss_store_session_func(const signal_protocol_address *address, uint8_t *record, size_t record_len, uint8_t *user_record, size_t user_record_len, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_session = {
        .mv_data = NULL,
        .mv_size = strlen("session_") + 10 + //strlen(address->device_id) +
             1 + strlen(address->name),
    };
    MDB_val v_session = {.mv_data = record, .mv_size = record_len};
    MDB_val k_user = {
        .mv_data = NULL,
        .mv_size = strlen("user_") + 10 + //strlen(address->device_id) +
             1 + strlen(address->name),
    };
    MDB_val v_user = {.mv_data = user_record, .mv_size = user_record_len};

    k_session.mv_data = malloc(sizeof(char) * (
                                           k_session.mv_size + 1));
    k_session.mv_size =
    snprintf(k_session.mv_data, k_session.mv_size,
             "session_%u_%s", address->device_id, address->name);
    k_user.mv_data = malloc(sizeof(char) * (
                                           k_user.mv_size + 1));
    k_user.mv_size =
    snprintf(k_user.mv_data, k_user.mv_size,
             "user_%u_%s", address->device_id, address->name);

    if (mdb_txn_begin(omemo->db->env, NULL, 0, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        return -1;
    }

    if (mdb_put(transaction, omemo->db->dbi_omemo,
                &k_session, &v_session, 0)/* ||
        mdb_put(transaction, omemo->db->dbi_omemo,
                &k_user, &v_user, 0)*/) {
      weechat_printf(NULL, "%sxmpp: failed to write lmdb value",
                     weechat_prefix("error"));
      return -1;
    };

    if (mdb_txn_commit(transaction)) {
      weechat_printf(NULL, "%sxmpp: failed to write lmdb transaction",
                     weechat_prefix("error"));
      return -1;
    };

    return 0;
}

int ss_contains_session_func(const signal_protocol_address *address, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_session = {
        .mv_data = NULL,
        .mv_size = strlen("session_") + 10 + //strlen(address->device_id) +
             1 + strlen(address->name),
    };
    MDB_val v_session;

    k_session.mv_data = malloc(sizeof(char) * (
                                           k_session.mv_size + 1));
    k_session.mv_size =
        snprintf(k_session.mv_data, k_session.mv_size,
                 "session_%u_%s", address->device_id, address->name);

    if (mdb_txn_begin(omemo->db->env, NULL, MDB_RDONLY, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        return -1;
    }

    if (mdb_get(transaction, omemo->db->dbi_omemo, &k_session, &v_session)) {
        mdb_txn_abort(transaction);
        return 1;
    };

    mdb_txn_abort(transaction);

    return 0;
}

int ss_delete_session_func(const signal_protocol_address *address, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_session = {
        .mv_data = NULL,
        .mv_size = strlen("session_") + 10 + //strlen(address->device_id) +
             1 + strlen(address->name),
    };
    MDB_val v_session;

    k_session.mv_data = malloc(sizeof(char) * (
                                           k_session.mv_size + 1));
    k_session.mv_size =
        snprintf(k_session.mv_data, k_session.mv_size,
                 "session_%u_%s", address->device_id, address->name);

    if (mdb_txn_begin(omemo->db->env, NULL, 0, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        return -1;
    }

    if (mdb_del(transaction, omemo->db->dbi_omemo, &k_session, &v_session)) {
        weechat_printf(NULL, "%sxmpp: failed to erase lmdb value",
                       weechat_prefix("error"));
        return -1;
    };

    if (mdb_txn_commit(transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to close lmdb transaction",
                       weechat_prefix("error"));
        return -1;
    };

    return 1;
}

int ss_delete_all_sessions_func(const char *name, size_t name_len, void *user_data)
{
    signal_int_list *sessions;
    ss_get_sub_device_sessions_func(&sessions, name, name_len, user_data);

    int n = signal_int_list_size(sessions);
    for (int i = 0; i < n; i++)
    {
        signal_protocol_address address = {.name = name, .name_len = name_len,
            .device_id = signal_int_list_at(sessions, i)};
        ss_delete_session_func(&address, user_data);
    }
    signal_int_list_free(sessions);
    return -1;
}

void ss_destroy_func(void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    (void) omemo;
    // Function called to perform cleanup when the data store context is being destroyed
}

int sks_store_sender_key(const signal_protocol_sender_key_name *sender_key_name, uint8_t *record, size_t record_len, uint8_t *user_record, size_t user_record_len, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    char *device_list = NULL;
    MDB_txn *transaction;
    MDB_val k_sender_key = {
        .mv_data = NULL,
        .mv_size = strlen("sender_key_") + strlen(sender_key_name->group_id) +
             1 + 10 + //strlen(sender_key_name->sender.device_id) +
             1 + strlen(sender_key_name->sender.name),
    };
    MDB_val v_sender_key = {.mv_data = record, .mv_size = record_len};
    MDB_val k_user = {
        .mv_data = NULL,
        .mv_size = strlen("user_") + strlen(sender_key_name->group_id) +
             1 + 10 + //strlen(sender_key_name->sender.device_id) +
             1 + strlen(sender_key_name->sender.name),
    };
    MDB_val v_user = {.mv_data = user_record, .mv_size = user_record_len};
    MDB_val k_device_ids = {
        .mv_data = NULL,
        .mv_size = strlen("device_ids_") + strlen(sender_key_name->sender.name),
    };
    MDB_val v_device_ids;

    k_sender_key.mv_data = malloc(sizeof(char) * (
                                           k_sender_key.mv_size + 1));
    k_sender_key.mv_size =
    snprintf(k_sender_key.mv_data, k_sender_key.mv_size,
             "sender_key_%s_%u_%s", sender_key_name->group_id,
             sender_key_name->sender.device_id,
             sender_key_name->sender.name);
    k_user.mv_data = malloc(sizeof(char) * (
                                           k_user.mv_size + 1));
    k_user.mv_size =
    snprintf(k_user.mv_data, k_user.mv_size,
             "user_%s_%u_%s", sender_key_name->group_id,
             sender_key_name->sender.device_id,
             sender_key_name->sender.name);
    k_device_ids.mv_data = malloc(sizeof(char) * (
                                           k_device_ids.mv_size + 1));
    snprintf(k_device_ids.mv_data, k_device_ids.mv_size,
             "device_ids_%s", sender_key_name->sender.name);

    if (mdb_txn_begin(omemo->db->env, NULL, 0, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        return -1;
    }

    if (!mdb_get(transaction, omemo->db->dbi_omemo,
                 &k_device_ids, &v_device_ids))
    {
        char **argv;
        int argc, i;

        argv = weechat_string_split(v_device_ids.mv_data, " ", NULL, 0, 0, &argc);
        for (i = 0; i < argc; i++)
        {
            char* device_id = argv[i];
            if (strtol(device_id, NULL, 10) == sender_key_name->sender.device_id) break;
        }

        weechat_string_free_split(argv);
        
        if (i == argc)
        {
            size_t device_list_len = strlen(v_device_ids.mv_data) + 1 + 10 + 1;
            device_list = malloc(sizeof(char) * device_list_len);
            snprintf(device_list, device_list_len, "%s %u",
                     (char*)v_device_ids.mv_data, sender_key_name->sender.device_id);
            v_device_ids.mv_data = device_list;
            v_device_ids.mv_size = strlen(device_list) + 1;
        }
    }
    else
    {
        device_list = malloc(sizeof(char) * (10 + 1));
        snprintf(device_list, 10 + 1, "%u", sender_key_name->sender.device_id);
        v_device_ids.mv_data = device_list;
        v_device_ids.mv_size = strlen(device_list) + 1;
    }

    if (mdb_put(transaction, omemo->db->dbi_omemo,
                &k_sender_key, &v_sender_key, 0)/* ||
        mdb_put(transaction, omemo->db->dbi_omemo,
                &k_user, &v_user, 0)*/ ||
        mdb_put(transaction, omemo->db->dbi_omemo,
                &k_device_ids, &v_device_ids, 0)) {
      weechat_printf(NULL, "%sxmpp: failed to write lmdb value",
                     weechat_prefix("error"));
      free(device_list);
      return -1;
    };

    if (mdb_txn_commit(transaction)) {
      weechat_printf(NULL, "%sxmpp: failed to write lmdb transaction",
                     weechat_prefix("error"));
      free(device_list);
      return -1;
    };
    free(device_list);

    return 0;
}

int sks_load_sender_key(signal_buffer **record, signal_buffer **user_record, const signal_protocol_sender_key_name *sender_key_name, void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    MDB_txn *transaction;
    MDB_val k_sender_key = {
        .mv_data = NULL,
        .mv_size = strlen("sender_key_") + strlen(sender_key_name->group_id) +
             1 + 10 + //strlen(sender_key_name->sender.device_id) +
             1 + strlen(sender_key_name->sender.name),
    };
    MDB_val v_sender_key;
    MDB_val k_user = {
        .mv_data = NULL,
        .mv_size = strlen("user_") + strlen(sender_key_name->group_id) +
             1 + 10 + //strlen(sender_key_name->sender.device_id) +
             1 + strlen(sender_key_name->sender.name),
    };
    MDB_val v_user;

    k_sender_key.mv_data = malloc(sizeof(char) * (
                                           k_sender_key.mv_size + 1));
    k_sender_key.mv_size =
    snprintf(k_sender_key.mv_data, k_sender_key.mv_size,
             "sender_key_%s_%u_%s", sender_key_name->group_id,
             sender_key_name->sender.device_id,
             sender_key_name->sender.name);
    k_user.mv_data = malloc(sizeof(char) * (
                                           k_user.mv_size + 1));
    k_user.mv_size =
    snprintf(k_user.mv_data, k_user.mv_size,
             "user_%s_%u_%s", sender_key_name->group_id,
             sender_key_name->sender.device_id,
             sender_key_name->sender.name);

    if (mdb_txn_begin(omemo->db->env, NULL, 0, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
    }

    if (mdb_get(transaction, omemo->db->dbi_omemo,
                &k_sender_key, &v_sender_key)/* &&
        mdb_get(transaction, omemo->db->dbi_omemo,
                &k_user, &v_user)*/)
    {
        *record = signal_buffer_create(v_sender_key.mv_data, v_sender_key.mv_size);
      //*user_record = signal_buffer_create(v_user.mv_data, v_user.mv_size);

        if (mdb_txn_commit(transaction)) {
            weechat_printf(NULL, "%sxmpp: failed to close lmdb transaction",
                           weechat_prefix("error"));
            return -1;
        };
    }
    else
    {
        /*
        signal_protocol_key_helper_sender_key_list_node *sender_keys_list;
        session_sender_key *sender_key = NULL;

        signal_protocol_key_helper_generate_sender_keys(
            &sender_keys_list, 0, 100, omemo->context);
        sender_key = signal_protocol_key_helper_key_list_element(sender_keys_list);
        signal_protocol_key_helper_key_list_next(sender_keys_list);

        uint32_t id = session_sender_key_get_id(sender_key); (void) id;
        session_sender_key_serialize(record, sender_key);

        signal_protocol_key_helper_key_list_free(sender_keys_list);

        v_sender_key.mv_data = signal_buffer_data(*record);
        v_sender_key.mv_size = signal_buffer_len(*record);

        if (mdb_put(transaction, omemo->db->dbi_omemo,
                    &k_sender_key, &v_sender_key, MDB_NOOVERWRITE))
        {
            weechat_printf(NULL, "%sxmpp: failed to read lmdb value",
                           weechat_prefix("error"));
            return -1;
        };

        if (mdb_txn_commit(transaction)) {
            weechat_printf(NULL, "%sxmpp: failed to write lmdb transaction",
                           weechat_prefix("error"));
            return -1;
        };
        */
        return -1;
    }

    return 0;
}

void sks_destroy_func(void *user_data)
{
    struct t_omemo *omemo = (struct t_omemo *)user_data;
    (void) omemo;
    // Function called to perform cleanup when the data store context is being destroyed
}

void omemo__log_emit_weechat(int level, const char *message, size_t len, void *user_data)
{
    struct t_gui_buffer *buffer = (struct t_gui_buffer*)user_data;

    static const char *log_level_name[5] = {"error", "warn", "notice", "info", "debug"};

    const char *tags = level < SG_LOG_DEBUG ? "no_log" : NULL;

    weechat_printf_date_tags(
        buffer, 0, tags,
        _("%somemo (%s): %.*s"),
        weechat_prefix("network"),
        log_level_name[level], len, message);
}

xmpp_stanza_t *omemo__get_bundle(xmpp_ctx_t *context, char *from, char *to,
                                 struct t_omemo *omemo)
{
    xmpp_stanza_t **children = malloc(sizeof(*children) * (100 + 1));
    xmpp_stanza_t *parent = NULL;
    signal_buffer *record = NULL;
    ec_key_pair *keypair = NULL;
    ec_public_key *public_key = NULL;

    int num_keys = 0;
    for (uint32_t id = PRE_KEY_START;
            id < INT_MAX && num_keys < 100; id++)
    {
        if (pks_load_pre_key(&record, id, omemo) != 0) continue;
        else num_keys++;
        session_pre_key *pre_key = NULL;
        session_pre_key_deserialize(&pre_key, signal_buffer_data(record),
                signal_buffer_len(record), omemo->context);
        if (pre_key == 0) (*((int*)0))++;
        signal_buffer_free(record);
        keypair = session_pre_key_get_key_pair(pre_key);
        public_key = ec_key_pair_get_public(keypair);
        ec_public_key_serialize(&record, public_key);
        char *data = NULL;
        base64_encode(signal_buffer_data(record),
                signal_buffer_len(record), &data);
        signal_buffer_free(record);
        if (pre_key) session_pre_key_destroy((signal_type_base*)pre_key);
      //SIGNAL_UNREF(pre_key);
        char *id_str = malloc(sizeof(char) * (10 + 1));
        snprintf(id_str, 10+1, "%u", id);
        children[num_keys-1] = stanza__iq_pubsub_publish_item_bundle_prekeys_preKeyPublic(
                context, NULL, NULL, with_free(id_str));
        stanza__set_text(context, children[num_keys-1], with_free(data));
    }
    children[100] = NULL;

    children[3] = stanza__iq_pubsub_publish_item_bundle_prekeys(
            context, NULL, children);
    children[4] = NULL;

    spks_load_signed_pre_key(&record, 1, omemo);
    session_signed_pre_key *signed_pre_key;
    session_signed_pre_key_deserialize(&signed_pre_key,
            signal_buffer_data(record), signal_buffer_len(record),
            omemo->context);
    signal_buffer_free(record);
    uint32_t signed_pre_key_id = session_signed_pre_key_get_id(signed_pre_key);
    keypair = session_signed_pre_key_get_key_pair(signed_pre_key);
    public_key = ec_key_pair_get_public(keypair);
    ec_public_key_serialize(&record, public_key);
    char *signed_pre_key_public = NULL;
    base64_encode(signal_buffer_data(record), signal_buffer_len(record),
            &signed_pre_key_public);
    signal_buffer_free(record);
    char *signed_pre_key_id_str = malloc(sizeof(char) * (10 + 1));
    snprintf(signed_pre_key_id_str, 10+1, "%u", signed_pre_key_id);
    children[0] = stanza__iq_pubsub_publish_item_bundle_signedPreKeyPublic(
            context, NULL, NULL, with_free(signed_pre_key_id_str));
    stanza__set_text(context, children[0], with_free(signed_pre_key_public));

    const uint8_t *keysig = session_signed_pre_key_get_signature(signed_pre_key);
    size_t keysig_len = session_signed_pre_key_get_signature_len(signed_pre_key);
    session_pre_key_destroy((signal_type_base*)signed_pre_key);
    char *signed_pre_key_signature = NULL;
    base64_encode(keysig, keysig_len, &signed_pre_key_signature);
    children[1] = stanza__iq_pubsub_publish_item_bundle_signedPreKeySignature(
            context, NULL, NULL);
    stanza__set_text(context, children[1], with_free(signed_pre_key_signature));

    iks_get_identity_key_pair(&record, (signal_buffer**)&signed_pre_key, omemo);
    char *identity_key = NULL;
    base64_encode(signal_buffer_data(record), signal_buffer_len(record),
            &identity_key);
    signal_buffer_free(record);
    children[2] = stanza__iq_pubsub_publish_item_bundle_identityKey(
            context, NULL, NULL);
    stanza__set_text(context, children[2], with_free(identity_key));

    children[0] = stanza__iq_pubsub_publish_item_bundle(
            context, NULL, children, with_noop("eu.siacs.conversations.axolotl"));
    children[1] = NULL;

    children[0] = stanza__iq_pubsub_publish_item(
            context, NULL, children, NULL);

    size_t bundle_node_len = strlen("eu.siacs.conversations.axolotl.bundles:") + 10;
    char *bundle_node = malloc(sizeof(char) * (bundle_node_len + 1));
    snprintf(bundle_node, bundle_node_len+1,
            "eu.siacs.conversations.axolotl.bundles:%u", omemo->device_id);
    children[0] = stanza__iq_pubsub_publish(
            context, NULL, children, with_free(bundle_node));

    children[0] = stanza__iq_pubsub(
            context, NULL, children, with_noop("http://jabber.org/protocol/pubsub"));

    parent = stanza__iq(
            context, NULL, children, NULL, "announce2", from, to, "set");
    free(children);

    return parent;
}

void omemo__init(struct t_gui_buffer *buffer, struct t_omemo **omemo,
                 const char *account_name)
{
    struct t_omemo *new_omemo;

    gcry_check_version(NULL);

    new_omemo = calloc(1, sizeof(**omemo));

    new_omemo->db = malloc(sizeof(struct t_omemo_db));

    signal_context_create(&new_omemo->context, buffer);
    signal_context_set_log_function(new_omemo->context, &omemo__log_emit_weechat);

    mdb_env_create(&new_omemo->db->env);
    mdb_env_set_maxdbs(new_omemo->db->env, 50);
    mdb_env_set_mapsize(new_omemo->db->env, (size_t)1048576 * 100000); // 1MB * 100000
    new_omemo->db_path = weechat_string_eval_expression("${weechat_data_dir}/xmpp.omemo.db",
                                                NULL, NULL, NULL);
    if (mdb_env_open(new_omemo->db->env, new_omemo->db_path, MDB_NOSUBDIR, 0664) != 0)
    {
        return;
    }

    MDB_txn *parentTransaction = NULL;
    MDB_txn *transaction;
    if (mdb_txn_begin(new_omemo->db->env, parentTransaction, 0 ? MDB_RDONLY : 0, &transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb transaction",
                       weechat_prefix("error"));
        return;
    }

    size_t db_name_len = strlen("omemo_") + strlen(account_name);
    char *db_name = malloc(sizeof(char) * (db_name_len + 1));
    snprintf(db_name, db_name_len+1, "omemo_%s", account_name);
    if (mdb_dbi_open(transaction, db_name, MDB_DUPSORT | MDB_CREATE, &new_omemo->db->dbi_omemo)) {
        weechat_printf(NULL, "%sxmpp: failed to open lmdb database",
                       weechat_prefix("error"));
        return;
    }

    if (mdb_txn_commit(transaction)) {
        weechat_printf(NULL, "%sxmpp: failed to close lmdb transaction",
                       weechat_prefix("error"));
        return;
    };

    struct signal_crypto_provider crypto_provider = {
        .random_func = &cp_random_generator,
        .hmac_sha256_init_func = &cp_hmac_sha256_init,
        .hmac_sha256_update_func = &cp_hmac_sha256_update,
        .hmac_sha256_final_func = &cp_hmac_sha256_final,
        .hmac_sha256_cleanup_func = &cp_hmac_sha256_cleanup,
        .sha512_digest_init_func = &cp_sha512_digest_init,
        .sha512_digest_update_func = &cp_sha512_digest_update,
        .sha512_digest_final_func = &cp_sha512_digest_final,
        .sha512_digest_cleanup_func = &cp_sha512_digest_cleanup,
        .encrypt_func = &cp_encrypt,
        .decrypt_func = &cp_decrypt,
        .user_data = new_omemo,
    };

    signal_context_set_crypto_provider(new_omemo->context, &crypto_provider);
    signal_context_set_locking_functions(new_omemo->context, &lock_function, &unlock_function);

    signal_protocol_store_context_create(&new_omemo->store_context, new_omemo->context);

    struct signal_protocol_identity_key_store identity_key_store = {
        .get_identity_key_pair = &iks_get_identity_key_pair,
        .get_local_registration_id = &iks_get_local_registration_id,
        .save_identity = &iks_save_identity,
        .is_trusted_identity = &iks_is_trusted_identity,
        .destroy_func = &iks_destroy_func,
        .user_data = new_omemo,
    };

    signal_protocol_store_context_set_identity_key_store(
        new_omemo->store_context, &identity_key_store);

    struct signal_protocol_pre_key_store pre_key_store = {
        .load_pre_key = &pks_load_pre_key,
        .store_pre_key = &pks_store_pre_key,
        .contains_pre_key = &pks_contains_pre_key,
        .remove_pre_key = &pks_remove_pre_key,
        .destroy_func = &pks_destroy_func,
        .user_data = new_omemo,
    };

    signal_protocol_store_context_set_pre_key_store(
        new_omemo->store_context, &pre_key_store);

    struct signal_protocol_signed_pre_key_store signed_pre_key_store = {
        .load_signed_pre_key = &spks_load_signed_pre_key,
        .store_signed_pre_key = &spks_store_signed_pre_key,
        .contains_signed_pre_key = &spks_contains_signed_pre_key,
        .remove_signed_pre_key = &spks_remove_signed_pre_key,
        .destroy_func = &spks_destroy_func,
        .user_data = new_omemo,
    };

    signal_protocol_store_context_set_signed_pre_key_store(
        new_omemo->store_context, &signed_pre_key_store);

    struct signal_protocol_session_store session_store = {
        .load_session_func = &ss_load_session_func,
        .get_sub_device_sessions_func = &ss_get_sub_device_sessions_func,
        .store_session_func = &ss_store_session_func,
        .contains_session_func = &ss_contains_session_func,
        .delete_session_func = &ss_delete_session_func,
        .delete_all_sessions_func = &ss_delete_all_sessions_func,
        .destroy_func = &ss_destroy_func,
        .user_data = new_omemo,
    };

    signal_protocol_store_context_set_session_store(
        new_omemo->store_context, &session_store);

    struct signal_protocol_sender_key_store sender_key_store = {
        .store_sender_key = &sks_store_sender_key,
        .load_sender_key = &sks_load_sender_key,
        .destroy_func = &sks_destroy_func,
        .user_data = new_omemo,
    };

    signal_protocol_store_context_set_sender_key_store(
        new_omemo->store_context, &sender_key_store);

    signal_buffer *public_data, *private_data;
    iks_get_local_registration_id(new_omemo, &new_omemo->device_id);
    if (!iks_get_identity_key_pair(&public_data, &private_data, new_omemo))
    {
        ec_public_key *public_key = NULL;
        ec_private_key *private_key = NULL;
        curve_decode_point(&public_key, signal_buffer_data(public_data),
                signal_buffer_len(public_data), new_omemo->context);
        curve_decode_private_point(&private_key, signal_buffer_data(private_data),
                signal_buffer_len(private_data), new_omemo->context);
        ratchet_identity_key_pair_create(&new_omemo->identity, public_key, private_key);
    }

    *omemo = new_omemo;
}

void omemo__handle_devicelist(struct t_omemo *omemo, const char *jid,
                              xmpp_stanza_t *items)
{
    (void) omemo;

    xmpp_stanza_t *item = xmpp_stanza_get_child_by_name(items, "item");
    if (!item) return;
    xmpp_stanza_t *list = xmpp_stanza_get_child_by_name(item, "list");
    if (!list) return;
    for (xmpp_stanza_t *device = xmpp_stanza_get_children(list);
         device; device = xmpp_stanza_get_next(device))
    {
        const char *name = xmpp_stanza_get_name(device);
        if (weechat_strcasecmp(name, "device") != 0)
            continue;

        const char *device_id = xmpp_stanza_get_id(device);
        if (!device_id)
            continue;

      //weechat_printf(NULL, "omemo devicelist %s: %s%u",
      //               jid, weechat_color("yellow"), strtol(device_id, NULL, 10));
    }
}

void omemo__handle_bundle(struct t_omemo *omemo, const char *jid,
                          uint32_t device_id, xmpp_stanza_t *items)
{
    (void) omemo;

    xmpp_stanza_t *item = xmpp_stanza_get_child_by_name(items, "item");
    if (!item) return;
    xmpp_stanza_t *bundle = xmpp_stanza_get_child_by_name(item, "bundle");
    if (!bundle) return;
    xmpp_stanza_t *signedprekey = xmpp_stanza_get_child_by_name(bundle, "signedPreKeyPublic");
    if (!signedprekey) return;
    const char *signed_pre_key = xmpp_stanza_get_text(signedprekey);
    if (!signed_pre_key) return;
    const char *signed_pre_key_id = xmpp_stanza_get_attribute(signedprekey, "signedPreKeyId");
    if (!signed_pre_key_id) return;
    xmpp_stanza_t *signature = xmpp_stanza_get_child_by_name(bundle, "signedPreKeySignature");
    if (!signature) return;
    const char *key_signature = xmpp_stanza_get_text(signature);
    if (!key_signature) return;
    xmpp_stanza_t *identitykey = xmpp_stanza_get_child_by_name(bundle, "identityKey");
    if (!identitykey) return;
    const char *identity_key = xmpp_stanza_get_text(identitykey);
    if (!identity_key) return;
    xmpp_stanza_t *prekeys = xmpp_stanza_get_child_by_name(bundle, "prekeys");
    if (!prekeys) return;

    char **format = weechat_string_dyn_alloc(256);
    weechat_string_dyn_concat(format, "omemo bundle %s/%u:\n%s..SPK %u: %s\n%3$s..SKS: %s\n%3$s..IK: %s", -1);
    for (xmpp_stanza_t *prekey = xmpp_stanza_get_children(prekeys);
         prekey; prekey = xmpp_stanza_get_next(prekey))
    {
        const char *name = xmpp_stanza_get_name(prekey);
        if (weechat_strcasecmp(name, "preKeyPublic") != 0)
            continue;

        const char *pre_key_id = xmpp_stanza_get_attribute(prekey, "preKeyId");
        if (!pre_key_id)
            continue;
        const char *pre_key = xmpp_stanza_get_text(prekey);
        if (!pre_key)
            continue;

        weechat_string_dyn_concat(format, "\n%3$s..PK ", -1);
        weechat_string_dyn_concat(format, pre_key_id, -1);
        weechat_string_dyn_concat(format, ": ", -1);
        weechat_string_dyn_concat(format, pre_key, -1);
    }
  //weechat_printf(NULL, *format, jid, device_id, weechat_color("green"),
  //               signed_pre_key_id, signed_pre_key,
  //               key_signature, identity_key);
    weechat_string_dyn_free(format, 1);
}

char *omemo__decode(struct t_omemo *omemo, const char *jid,
                             xmpp_stanza_t *encrypted)
{
    uint8_t *key_data = NULL, *iv_data = NULL, *payload_data = NULL;
    size_t key_len = 0, iv_len = 0, payload_len = 0;

    xmpp_stanza_t *header = xmpp_stanza_get_child_by_name(encrypted, "header");
    if (!header) return NULL;
    xmpp_stanza_t *iv = xmpp_stanza_get_child_by_name(header, "iv");
    if (!iv) return NULL;
    const char *iv__text = xmpp_stanza_get_text(iv);
    if (!iv__text) return NULL;
    iv_len = base64_decode(iv__text, strlen(iv__text), &iv_data);

    char **format = weechat_string_dyn_alloc(256);
    weechat_string_dyn_concat(format, "omemo msg %s:\n%s..IV: %s", -1);
    for (xmpp_stanza_t *key = xmpp_stanza_get_children(header);
         key; key = xmpp_stanza_get_next(key))
    {
        const char *name = xmpp_stanza_get_name(key);
        if (weechat_strcasecmp(name, "key") != 0)
            continue;

        const char *key_prekey = xmpp_stanza_get_attribute(key, "prekey");
        const char *key_id = xmpp_stanza_get_attribute(key, "rid");
        if (!key_id)
            continue;
        uint32_t id = strtol(key_id, NULL, 10);
        if (id != omemo->device_id)
            continue;
        const char *data = xmpp_stanza_get_text(key);
        if (!data)
            continue;
        key_len = base64_decode(data, strlen(data), &key_data);

        // signal decrypt key for id

        weechat_string_dyn_concat(format, "\n%2$s..K ", -1);
        if (key_prekey)
            weechat_string_dyn_concat(format, "*", -1);
        weechat_string_dyn_concat(format, key_id, -1);
        weechat_string_dyn_concat(format, ": ", -1);
        weechat_string_dyn_concat(format, data, -1);
    }

    xmpp_stanza_t *payload = xmpp_stanza_get_child_by_name(encrypted, "payload");
    if (payload)
    {
        const char *payload__text = xmpp_stanza_get_text(payload);
        if (!payload__text) return NULL;
        payload_len = base64_decode(payload__text, strlen(payload__text), &payload_data);
        weechat_string_dyn_concat(format, "\n%2$s..PL: ", -1);
        weechat_string_dyn_concat(format, payload__text, -1);
    }
    weechat_printf(NULL, *format, jid, weechat_color("red"), iv__text);
    weechat_string_dyn_free(format, 1);

    if (!(payload_data && iv_data && key_data) || key_len <= 16) return NULL;
    char *plaintext = NULL; size_t plaintext_len = 0;
    if (aes_decrypt(payload_data, payload_len, key_data, iv_data,
                    key_data+AES_KEY_SIZE, key_len-AES_KEY_SIZE,
                    (uint8_t**)&plaintext, &plaintext_len) && plaintext)
    {
        plaintext[plaintext_len] = '\0';
        return plaintext;
    }
    return NULL;
}

xmpp_stanza_t *omemo__encode(struct t_omemo *omemo, const char *jid,
                             uint32_t device_id, const char *unencrypted)
{
    uint8_t *key = NULL; uint8_t *iv = NULL;
    uint8_t *tag = NULL; size_t tag_len = 0;
    uint8_t *ciphertext = NULL; size_t ciphertext_len = 0;
    aes_encrypt((uint8_t*)unencrypted, strlen(unencrypted),
                &key, &iv, &tag, &tag_len,
                &ciphertext, &ciphertext_len);

    uint8_t *key_and_tag = malloc(sizeof(uint8_t) * (AES_KEY_SIZE+tag_len));
    memcpy(key_and_tag, key, AES_KEY_SIZE);
    free(key);
    memcpy(key_and_tag+AES_KEY_SIZE, tag, tag_len);
    free(tag);
    char *key64 = NULL;
    base64_encode(key_and_tag, AES_KEY_SIZE+tag_len, &key64);
    char *iv64 = NULL;
    base64_encode(iv, AES_IV_SIZE, &iv64);
    free(iv);
    char *ciphertext64 = NULL;
    base64_encode(ciphertext, ciphertext_len, &ciphertext64);
    free(ciphertext);

    signal_buffer *record;
    signal_protocol_address address = {
        .name = jid, .name_len = strlen(jid), .device_id = device_id};

    /*
    session_builder *builder;
    session_builder_create(&builder, omemo->store_context, &address, omemo->context);
  //session_builder_process_pre_key_bundle(builder, pre_key);

    session_cipher *cipher;
    session_cipher_create(&cipher, omemo->store_context, &address, omemo->context);

    ciphertext_message *encrypted_message;
    session_cipher_encrypt(cipher, key_and_tag, AES_KEY_SIZE+tag_len, &encrypted_message);
    signal_buffer *serialized = ciphertext_message_get_serialized(encrypted_message);
    int prekey = ciphertext_message_get_type(encrypted_message) == CIPHERTEXT_PREKEY_TYPE
        ? 1 : 0;

    char *payload = NULL;
    base64_encode(signal_buffer_data(serialized), signal_buffer_len(serialized),
            &payload);
    weechat_printf(NULL, "signal send %s/%u: %s%s\n..%sMessage: %s",
                   jid, device_id, weechat_color("blue"), key64,
                   prekey ? "PreKey" : "", payload);

    signal_buffer_free(serialized);
    SIGNAL_UNREF(encrypted_message);
    session_cipher_free(cipher);
    session_builder_free(builder);
    */
    free(key_and_tag);

    // ...
    weechat_printf(NULL, "omemo send %s/%u: %s%s\n..Key: %s\n..IV: %s\n..Payload: %s",
                   jid, device_id, weechat_color("blue"), unencrypted,
                   key64, iv64, ciphertext64);
    free(iv64);
    free(key64);
    free(ciphertext64);
    return NULL;
}

void omemo__free(struct t_omemo *omemo)
{
    if (omemo)
    {
        if (omemo->context) {
            signal_context_destroy(omemo->context);
            signal_protocol_store_context_destroy(omemo->store_context);
        }
        if (omemo->identity)
            ratchet_identity_key_pair_destroy(
                (signal_type_base *)omemo->identity);
        free(omemo->db_path);
        free(omemo);
    }
}