/* SPDX-License-Identifier: GPL-3.0-or-later
 * Copyright © 2016-2026 The TokTok team.
 * Copyright © 2014 Tox project.
 */
#include "groupav.h"

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

#include "../toxcore/ccompat.h"
#include "../toxcore/logger.h"
#include "../toxcore/mono_time.h"
#include "../toxcore/tox_struct.h"
#include "../toxcore/util.h"

#define GROUP_JBUF_SIZE 6
#define GROUP_JBUF_DEAD_SECONDS 4

typedef struct Group_Audio_Packet {
    uint16_t sequnum;
    uint16_t length;
    uint8_t *data;
} Group_Audio_Packet;

typedef struct Group_JitterBuffer {
    Group_Audio_Packet **queue;
    uint32_t size;
    uint32_t capacity;
    uint16_t bottom;
    uint16_t top;
    uint64_t last_queued_time;
} Group_JitterBuffer;

static void free_audio_packet(Group_Audio_Packet *_Nullable pk)
{
    if (pk == nullptr) {
        return;
    }

    free(pk->data);
    free(pk);
}

static Group_JitterBuffer *_Nullable create_queue(unsigned int capacity)
{
    unsigned int size = 1;

    while (size <= capacity) {
        size *= 2;
    }

    Group_JitterBuffer *q = (Group_JitterBuffer *)calloc(1, sizeof(Group_JitterBuffer));

    if (q == nullptr) {
        return nullptr;
    }

    q->queue = (Group_Audio_Packet **)calloc(size, sizeof(Group_Audio_Packet *));

    if (q->queue == nullptr) {
        free(q);
        return nullptr;
    }

    q->size = size;
    q->capacity = capacity;
    return q;
}

static void clear_queue(Group_JitterBuffer *_Nonnull q)
{
    while (q->bottom != q->top) {
        const size_t idx = q->bottom % q->size;
        free_audio_packet(q->queue[idx]);
        q->queue[idx] = nullptr;
        ++q->bottom;
    }
}

static void terminate_queue(Group_JitterBuffer *_Nullable q)
{
    if (q == nullptr) {
        return;
    }

    clear_queue(q);
    free(q->queue);
    free(q);
}

/** @retval 0 if packet was queued
 * @retval -1 if it wasn't.
 */
static int queue(Group_JitterBuffer *_Nonnull q, const Mono_Time *_Nonnull mono_time, Group_Audio_Packet *_Nonnull pk)
{
    const uint16_t sequnum = pk->sequnum;

    const unsigned int num = sequnum % q->size;

    if (!mono_time_is_timeout(mono_time, q->last_queued_time, GROUP_JBUF_DEAD_SECONDS)) {
        if ((uint32_t)(sequnum - q->bottom) > (1 << 15)) {
            /* Drop old packet. */
            return -1;
        }
    }

    if ((uint32_t)(sequnum - q->bottom) > q->size) {
        clear_queue(q);
        q->bottom = sequnum - q->capacity;
        q->queue[num] = pk;
        q->top = sequnum + 1;
        q->last_queued_time = mono_time_get(mono_time);
        return 0;
    }

    if (q->queue[num] != nullptr) {
        return -1;
    }

    q->queue[num] = pk;

    if ((sequnum - q->bottom) >= (q->top - q->bottom)) {
        q->top = sequnum + 1;
    }

    q->last_queued_time = mono_time_get(mono_time);
    return 0;
}

/**
 * success is:
 * - 0 when there is nothing to dequeue
 * - 1 when there's a good packet
 * - 2 when there's a lost packet
 */
static Group_Audio_Packet *_Nullable dequeue(Group_JitterBuffer *_Nonnull q, int *_Nonnull success)
{
    if (q->top == q->bottom) {
        *success = 0;
        return nullptr;
    }

    const unsigned int num = q->bottom % q->size;

    if (q->queue[num] != nullptr) {
        Group_Audio_Packet *ret = q->queue[num];
        q->queue[num] = nullptr;
        ++q->bottom;
        *success = 1;
        return ret;
    }

    if ((uint32_t)(q->top - q->bottom) > q->capacity) {
        ++q->bottom;
        *success = 2;
        return nullptr;
    }

    *success = 0;
    return nullptr;
}

typedef struct Group_AV {
    const Logger *log;
    Tox *tox;
    Group_Chats *g_c;
    OpusEncoder *audio_encoder;

    unsigned int audio_channels;
    unsigned int audio_sample_rate;
    unsigned int audio_bitrate;

    uint16_t audio_sequnum;

    audio_data_cb *audio_data;
    void *userdata;
} Group_AV;

typedef struct Group_Peer_AV {
    const Mono_Time *mono_time;
    Group_JitterBuffer *buffer;

    OpusDecoder *audio_decoder;
    int decoder_channels;
    unsigned int last_packet_samples;
} Group_Peer_AV;

static void kill_group_av(Group_AV *_Nonnull group_av)
{
    if (group_av->audio_encoder != nullptr) {
        opus_encoder_destroy(group_av->audio_encoder);
    }

    free(group_av);
}

static int recreate_encoder(Group_AV *_Nonnull group_av)
{
    if (group_av->audio_encoder != nullptr) {
        opus_encoder_destroy(group_av->audio_encoder);
        group_av->audio_encoder = nullptr;
    }

    int rc = OPUS_OK;
    group_av->audio_encoder = opus_encoder_create(group_av->audio_sample_rate, group_av->audio_channels,
                              OPUS_APPLICATION_AUDIO, &rc);

    if (rc != OPUS_OK) {
        LOGGER_ERROR(group_av->log, "Error while starting audio encoder: %s", opus_strerror(rc));
        group_av->audio_encoder = nullptr;
        return -1;
    }

    rc = opus_encoder_ctl(group_av->audio_encoder, OPUS_SET_BITRATE(group_av->audio_bitrate));

    if (rc != OPUS_OK) {
        LOGGER_ERROR(group_av->log, "Error while setting encoder ctl: %s", opus_strerror(rc));
        opus_encoder_destroy(group_av->audio_encoder);
        group_av->audio_encoder = nullptr;
        return -1;
    }

    rc = opus_encoder_ctl(group_av->audio_encoder, OPUS_SET_COMPLEXITY(10));

    if (rc != OPUS_OK) {
        LOGGER_ERROR(group_av->log, "Error while setting encoder ctl: %s", opus_strerror(rc));
        opus_encoder_destroy(group_av->audio_encoder);
        group_av->audio_encoder = nullptr;
        return -1;
    }

    return 0;
}

static Group_AV *_Nullable new_group_av(const Logger *_Nonnull log, Tox *_Nonnull tox, Group_Chats *_Nonnull g_c, audio_data_cb *_Nullable audio_callback,
                                        void *_Nullable userdata)
{
    if (g_c == nullptr) {
        return nullptr;
    }

    Group_AV *group_av = (Group_AV *)calloc(1, sizeof(Group_AV));

    if (group_av == nullptr) {
        return nullptr;
    }

    group_av->log = log;
    group_av->tox = tox;
    group_av->g_c = g_c;

    group_av->audio_data = audio_callback;
    group_av->userdata = userdata;

    return group_av;
}

static void group_av_peer_new(void *_Nonnull object, Tox_Conference_Number conference_number, Tox_Conference_Peer_Number peer_number)
{
    const Group_AV *group_av = (const Group_AV *)object;
    Group_Peer_AV *peer_av = (Group_Peer_AV *)calloc(1, sizeof(Group_Peer_AV));

    if (peer_av == nullptr) {
        return;
    }

    peer_av->mono_time = g_mono_time(group_av->g_c);
    peer_av->buffer = create_queue(GROUP_JBUF_SIZE);

    if (group_peer_set_object(group_av->g_c, conference_number, peer_number, peer_av) == -1) {
        free(peer_av);
    }
}

static void group_av_peer_delete(void *_Nullable object, Tox_Conference_Number conference_number, void *_Nullable peer_object)
{
    Group_Peer_AV *peer_av = (Group_Peer_AV *)peer_object;

    if (peer_av == nullptr) {
        return;
    }

    if (peer_av->audio_decoder != nullptr) {
        opus_decoder_destroy(peer_av->audio_decoder);
    }

    terminate_queue(peer_av->buffer);
    free(peer_object);
}

static void group_av_groupchat_delete(void *_Nullable object, Tox_Conference_Number conference_number)
{
    Group_AV *group_av = (Group_AV *)object;
    if (group_av != nullptr) {
        kill_group_av(group_av);
    }
}

static int decode_audio_packet(Group_AV *_Nonnull group_av, Group_Peer_AV *_Nonnull peer_av, Tox_Conference_Number conference_number,
                               Tox_Conference_Peer_Number peer_number)
{
    if (group_av == nullptr || peer_av == nullptr) {
        return -1;
    }

    int success;
    Group_Audio_Packet *pk = dequeue(peer_av->buffer, &success);

    if (success == 0) {
        return -1;
    }

    int16_t *out_audio = nullptr;
    int out_audio_samples = 0;

    const uint32_t sample_rate = 48000;

    if (success == 1) {
        const int channels = opus_packet_get_nb_channels(pk->data);

        if (channels == OPUS_INVALID_PACKET) {
            free_audio_packet(pk);
            return -1;
        }

        if (channels != 1 && channels != 2) {
            free_audio_packet(pk);
            return -1;
        }

        if (channels != peer_av->decoder_channels) {
            if (peer_av->audio_decoder != nullptr) {
                opus_decoder_destroy(peer_av->audio_decoder);
                peer_av->audio_decoder = nullptr;
            }

            int rc;
            peer_av->audio_decoder = opus_decoder_create(sample_rate, channels, &rc);

            if (rc != OPUS_OK) {
                LOGGER_ERROR(group_av->log, "Error while starting audio decoder: %s", opus_strerror(rc));
                free_audio_packet(pk);
                return -1;
            }

            peer_av->decoder_channels = channels;
        }

        const int num_samples = opus_decoder_get_nb_samples(peer_av->audio_decoder, pk->data, pk->length);

        out_audio = (int16_t *)malloc(num_samples * peer_av->decoder_channels * sizeof(int16_t));

        if (out_audio == nullptr) {
            free_audio_packet(pk);
            return -1;
        }

        out_audio_samples = opus_decode(peer_av->audio_decoder, pk->data, pk->length, out_audio, num_samples, 0);
        free_audio_packet(pk);

        if (out_audio_samples <= 0) {
            free(out_audio);
            return -1;
        }

        peer_av->last_packet_samples = (unsigned int)out_audio_samples;
    } else {
        if (peer_av->audio_decoder == nullptr) {
            return -1;
        }

        if (peer_av->last_packet_samples == 0) {
            return -1;
        }

        out_audio = (int16_t *)malloc(peer_av->last_packet_samples * peer_av->decoder_channels * sizeof(int16_t));

        if (out_audio == nullptr) {
            free_audio_packet(pk);
            return -1;
        }

        out_audio_samples = opus_decode(peer_av->audio_decoder, nullptr, 0, out_audio, peer_av->last_packet_samples, 1);

        if (out_audio_samples <= 0) {
            free(out_audio);
            return -1;
        }
    }

    if (out_audio != nullptr) {

        if (group_av->audio_data != nullptr) {
            group_av->audio_data(group_av->tox, conference_number, peer_number, out_audio, (uint32_t)out_audio_samples,
                                 (uint8_t)peer_av->decoder_channels, sample_rate, group_av->userdata);
        }

        free(out_audio);
        return 0;
    }

    return -1;
}

static int handle_group_audio_packet(void *_Nonnull object, Tox_Conference_Number conference_number, Tox_Conference_Peer_Number peer_number, void *_Nonnull peer_object,
                                     const uint8_t *_Nonnull packet, uint16_t length)
{
    Group_AV *group_av = (Group_AV *)object;
    Group_Peer_AV *peer_av = (Group_Peer_AV *)peer_object;

    if (group_av == nullptr || peer_av == nullptr || length <= sizeof(uint16_t)) {
        return -1;
    }

    Group_Audio_Packet *pk = (Group_Audio_Packet *)calloc(1, sizeof(Group_Audio_Packet));

    if (pk == nullptr) {
        return -1;
    }

    net_unpack_u16(packet, &pk->sequnum);
    pk->length = length - sizeof(uint16_t);

    pk->data = (uint8_t *)malloc(pk->length);

    if (pk->data == nullptr) {
        free_audio_packet(pk);
        return -1;
    }

    memcpy(pk->data, packet + sizeof(uint16_t), pk->length);

    if (queue(peer_av->buffer, peer_av->mono_time, pk) == -1) {
        free_audio_packet(pk);
        return -1;
    }

    while (decode_audio_packet(group_av, peer_av, conference_number, peer_number) == 0) {
        /* Continue. */
    }

    return 0;
}

/** @brief Enable A/V in a conference.
 *
 * @retval 0 on success.
 * @retval -1 on failure.
 */
int groupchat_enable_av(const Logger *log, Tox *tox, Group_Chats *g_c, Tox_Conference_Number conference_number,
                        audio_data_cb *audio_callback, void *userdata)
{
    if (group_get_type(g_c, conference_number) != GROUPCHAT_TYPE_AV
            || group_get_object(g_c, conference_number) != nullptr) {
        return -1;
    }

    Group_AV *group_av = new_group_av(log, tox, g_c, audio_callback, userdata);

    if (group_av == nullptr) {
        return -1;
    }

    if (group_set_object(g_c, conference_number, group_av) == -1
            || callback_groupchat_peer_new(g_c, conference_number, group_av_peer_new) == -1
            || callback_groupchat_peer_delete(g_c, conference_number, group_av_peer_delete) == -1
            || callback_groupchat_delete(g_c, conference_number, group_av_groupchat_delete) == -1) {
        kill_group_av(group_av);
        return -1;
    }

    const int numpeers = group_number_peers(g_c, conference_number, false);

    if (numpeers < 0) {
        kill_group_av(group_av);
        return -1;
    }

    for (uint32_t i = 0; i < (uint32_t)numpeers; ++i) {
        group_av_peer_new(group_av, conference_number, i);
    }

    group_lossy_packet_registerhandler(g_c, GROUP_AUDIO_PACKET_ID, &handle_group_audio_packet);
    return 0;
}

/** @brief Disable A/V in a conference.
 *
 * @retval 0 on success.
 * @retval -1 on failure.
 */
int groupchat_disable_av(const Group_Chats *g_c, Tox_Conference_Number conference_number)
{
    if (group_get_type(g_c, conference_number) != GROUPCHAT_TYPE_AV) {
        return -1;
    }

    Group_AV *group_av = (Group_AV *)group_get_object(g_c, conference_number);

    if (group_av == nullptr) {
        return -1;
    }

    const int numpeers = group_number_peers(g_c, conference_number, false);

    if (numpeers < 0) {
        kill_group_av(group_av);
        return -1;
    }

    for (uint32_t i = 0; i < (uint32_t)numpeers; ++i) {
        group_av_peer_delete(group_av, conference_number, group_peer_get_object(g_c, conference_number, i));
        group_peer_set_object(g_c, conference_number, i, nullptr);
    }

    kill_group_av(group_av);

    if (group_set_object(g_c, conference_number, nullptr) == -1
            || callback_groupchat_peer_new(g_c, conference_number, nullptr) == -1
            || callback_groupchat_peer_delete(g_c, conference_number, nullptr) == -1
            || callback_groupchat_delete(g_c, conference_number, nullptr) == -1) {
        return -1;
    }

    return 0;
}

/** Return whether A/V is enabled in the conference. */
bool groupchat_av_enabled(const Group_Chats *g_c, Tox_Conference_Number conference_number)
{
    return group_get_object(g_c, conference_number) != nullptr;
}

/** @brief Create and connect to a new toxav group.
 *
 * @return conference number on success.
 * @retval -1 on failure.
 */
int add_av_groupchat(const Logger *log, Tox *tox, Group_Chats *g_c, audio_data_cb *audio_callback, void *userdata)
{
    const int conference_number = add_groupchat(g_c, tox->sys.rng, GROUPCHAT_TYPE_AV);

    if (conference_number == -1) {
        return -1;
    }

    if (groupchat_enable_av(log, tox, g_c, (Tox_Conference_Number)conference_number, audio_callback, userdata) == -1) {
        del_groupchat(g_c, (Tox_Conference_Number)conference_number, true);
        return -1;
    }

    return conference_number;
}

/** @brief Join a AV group (you need to have been invited first).
 *
 * @return conference number on success
 * @retval -1 on failure.
 */
int join_av_groupchat(const Logger *log, Tox *tox, Group_Chats *g_c, Tox_Friend_Number friend_number, const uint8_t *data,
                      uint16_t length, audio_data_cb *audio_callback, void *userdata)
{
    const int conference_number = join_groupchat(g_c, friend_number, GROUPCHAT_TYPE_AV, data, length);

    if (conference_number == -1) {
        return -1;
    }

    if (groupchat_enable_av(log, tox, g_c, (Tox_Conference_Number)conference_number, audio_callback, userdata) == -1) {
        del_groupchat(g_c, (Tox_Conference_Number)conference_number, true);
        return -1;
    }

    return conference_number;
}

/** @brief Send an encoded audio packet to the conference.
 *
 * @retval 0 on success.
 * @retval -1 on failure.
 */
static int send_audio_packet(const Group_Chats *_Nonnull g_c, Tox_Conference_Number conference_number, const uint8_t *_Nonnull packet, uint16_t length)
{
    if (length == 0 || length > MAX_CRYPTO_DATA_SIZE - 1 - sizeof(uint16_t)) {
        return -1;
    }

    const uint16_t plen = 1 + sizeof(uint16_t) + length;

    Group_AV *const group_av = (Group_AV *)group_get_object(g_c, conference_number);

    if (group_av == nullptr) {
        return -1;
    }

    uint8_t data[MAX_CRYPTO_DATA_SIZE];
    uint8_t *ptr = data;
    *ptr = GROUP_AUDIO_PACKET_ID;
    ++ptr;

    ptr += net_pack_u16(ptr, group_av->audio_sequnum);
    memcpy(ptr, packet, length);

    if (send_group_lossy_packet(g_c, conference_number, data, plen) == -1) {
        return -1;
    }

    ++group_av->audio_sequnum;
    return 0;
}

/** @brief Send audio to the conference.
 *
 * @retval 0 on success.
 * @retval -1 on failure.
 */
int group_send_audio(const Group_Chats *g_c, Tox_Conference_Number conference_number, const int16_t pcm[], uint32_t samples, uint8_t channels,
                     uint32_t sample_rate)
{
    Group_AV *group_av = (Group_AV *)group_get_object(g_c, conference_number);

    if (group_av == nullptr) {
        return -1;
    }

    if (channels != 1 && channels != 2) {
        return -1;
    }

    if (sample_rate != 8000 && sample_rate != 12000 && sample_rate != 16000 && sample_rate != 24000
            && sample_rate != 48000) {
        return -1;
    }

    if (group_av->audio_encoder == nullptr || group_av->audio_channels != channels
            || group_av->audio_sample_rate != sample_rate) {
        group_av->audio_channels = channels;
        group_av->audio_sample_rate = sample_rate;

        if (channels == 1) {
            group_av->audio_bitrate = 32000; // TODO(mannol): add way of adjusting bitrate
        } else {
            group_av->audio_bitrate = 64000; // TODO(mannol): add way of adjusting bitrate
        }

        if (recreate_encoder(group_av) == -1) {
            return -1;
        }
    }

    uint8_t encoded[1024];
    const int32_t size = opus_encode(group_av->audio_encoder, pcm, samples, encoded, sizeof(encoded));

    if (size <= 0) {
        return -1;
    }

    return send_audio_packet(g_c, conference_number, encoded, size);
}
