/*
 * Copyright (C) 2023 Linux Studio Plugins Project <https://lsp-plug.in/>
 *           (C) 2023 Vladimir Sadovnikov <sadko4u@gmail.com>
 *
 * This file is part of lsp-plugin-fw
 * Created on: 24 нояб. 2020 г.
 *
 * lsp-plugin-fw is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * any later version.
 *
 * lsp-plugin-fw is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with lsp-plugin-fw. If not, see <https://www.gnu.org/licenses/>.
 */

#include <lsp-plug.in/plug-fw/const.h>
#include <lsp-plug.in/plug-fw/core/KVTDispatcher.h>
#include <lsp-plug.in/plug-fw/plug.h>

namespace lsp
{
    namespace core
    {
        KVTDispatcher::KVTDispatcher(KVTStorage *kvt, ipc::Mutex *mutex)
        {
            pRx         = core::osc_buffer_t::create(OSC_BUFFER_MAX);
            pTx         = core::osc_buffer_t::create(OSC_BUFFER_MAX);
            pKVT        = kvt;
            pKVTMutex   = mutex;
            pPacket     = reinterpret_cast<uint8_t *>(::malloc(OSC_PACKET_MAX));
            atomic_store(&nClients, 0);
            atomic_store(&nTxRequest, 0);
        }

        KVTDispatcher::~KVTDispatcher()
        {
            if (pRx != NULL)
            {
                core::osc_buffer_t::destroy(pRx);
                pRx     = NULL;
            }
            if (pTx != NULL)
            {
                core::osc_buffer_t::destroy(pTx);
                pTx     = NULL;
            }
            if (pPacket != NULL)
            {
                ::free(pPacket);
                pPacket = NULL;
            }
        }

        size_t  KVTDispatcher::receive_changes()
        {
            size_t size, changes = 0;

            while (true)
            {
                // Fetch the packet
                status_t res    = pRx->fetch(pPacket, &size, OSC_PACKET_MAX);

                switch (res)
                {
                    case STATUS_OK:
                    {
                        lsp_trace("Received OSC message (%d bytes)", int(size));
                        osc::dump_packet(pPacket, size);

                        // Analyze parsing result
                        if ((res = parse_message(pKVT, pPacket, size, KVT_RX)) != STATUS_OK)
                        {
                            // Skipped message?
                            if (res != STATUS_SKIP)
                                return changes;
                        }
                        ++changes;
                        break;
                    }

                    case STATUS_OVERFLOW:
                        ++changes;
                        lsp_warn("Received too big OSC packet, skipping");
                        pRx->skip();
                        break;

                    case STATUS_NO_DATA:
                        return changes;

                    default:
                        lsp_warn("Received error while deserializing KVT changes: %d", int(res));
                        return changes;

                }
            }
        }

        size_t  KVTDispatcher::transmit_changes()
        {
            status_t res;
            size_t changes = 0;

            KVTIterator *iter = pKVT->enum_tx_pending();
            if (iter == NULL)
                return changes;

            const kvt_param_t *p;
            const char *kvt_name;
            size_t size;

            while (iter->next() == STATUS_OK)
            {
                // Do not transfer private properties
                if (iter->is_private())
                    continue;

                // Fetch next change
                res     = iter->get(&p);
                if (res == STATUS_NOT_FOUND)
                    continue;
                else if (res != STATUS_OK)
                    break;

                kvt_name = iter->name();
                if (kvt_name == NULL)
                    continue;;

                // Try to serialize changes
                res = build_message(kvt_name, p, pPacket, &size, OSC_PACKET_MAX);
                if (res != STATUS_OK)
                {
                    iter->commit(KVT_TX);
                    continue;
                }

                lsp_trace("Transmitting OSC message (%d bytes)", int(size));
                osc::dump_packet(pPacket, size);

                // Submit to queue
                res = pTx->submit(pPacket, size);

                switch (res)
                {
                    case STATUS_OK:
                        iter->commit(KVT_TX);
                        break;

                    case STATUS_TOO_BIG: // Packet too big
                        lsp_warn("Too large packet for parameter %s: %d bytes, skipping", kvt_name, int(size));
                        iter->commit(KVT_TX);
                        break;

                    case STATUS_OVERFLOW: // Not enough space to store the packet
                        return changes;

                    default:
                        return changes;
                }
            }

            return changes;
        }

        status_t KVTDispatcher::run()
        {
            while (!cancelled())
            {
                ssize_t changes     = iterate();
                if (changes <= 0)
                    Thread::sleep(100);     // No changes? Sleep for a while
            }

            return STATUS_OK;
        }

        ssize_t KVTDispatcher::iterate()
        {
            ssize_t changes     = 0;

            // Lock KVT storage and perform transfer
            if (!pKVTMutex->lock())
                return changes;
            lsp_finally { pKVTMutex->unlock(); };

            if (atomic_load(&nClients) > 0)
            {
                if (atomic_load(&nTxRequest) > 0)
                {
                    lsp_trace("Setting all KVT parameters as required for transfer");
                    pKVT->touch_all(KVT_TX);
                    atomic_add(&nTxRequest, -1);
                }

                changes    += receive_changes();    // Perform receive first
                changes    += transmit_changes();   // Perform transmit then
            }
            else
            {
                pTx->clear();
                pRx->clear();
            }
            pKVT->gc();                         // Perform garbage collection

            return changes;
        }

        status_t KVTDispatcher::submit(const void *data, size_t size)
        {
            return pRx->submit(data, size);
        }

        status_t KVTDispatcher::submit(const osc::packet_t *packet)
        {
            return pRx->submit(packet);
        }

        status_t KVTDispatcher::fetch(void *data, size_t *size, size_t limit)
        {
            return pTx->fetch(data, size, limit);
        }

        status_t KVTDispatcher::fetch(osc::packet_t *packet, size_t limit)
        {
            return pTx->fetch(packet, limit);
        }

        status_t KVTDispatcher::skip()
        {
            return pTx->skip();
        }

        void KVTDispatcher::connect_client()
        {
            atomic_add(&nClients, 1);
            atomic_add(&nTxRequest, 1);
        }

        void KVTDispatcher::disconnect_client()
        {
            if (atomic_add(&nClients, -1) == 0)
                atomic_store(&nTxRequest, 0);
        }

        status_t KVTDispatcher::parse_message(KVTStorage *kvt, const void *data, size_t size, size_t flags)
        {
            osc::parser_t parser;
            osc::parse_frame_t root, message;
            osc::parse_token_t token;

            const char *address;
            kvt_param_t p;
            status_t res;

            if ((res = osc::parse_begin(&root, &parser, data, size)) != STATUS_OK)
            {
                lsp_trace("Failed parse_begin()");
                return res;
            }

            if ((res = osc::parse_begin_message(&message, &root, &address)) != STATUS_OK)
            {
                lsp_trace("Failed parse_begin_message()");
                osc::parse_end(&root);
                osc::parse_destroy(&parser);
                return res;
            }

            if (::strstr(address, "/KVT/") != address) // Non-KVT destination?
            {
                lsp_trace("Prefix does not match /KVT/");
                osc::parse_end(&root);
                osc::parse_destroy(&parser);
                return STATUS_SKIP;
            }

            address += ::strlen("/KVT");
            lsp_trace("Parameter name = %s", address);

            if ((res = osc::parse_token(&message, &token)) != STATUS_OK)
            {
                lsp_trace("Could not fetch token");
                osc::parse_end(&message);
                osc::parse_end(&root);
                osc::parse_destroy(&parser);
                return res;
            }
            lsp_trace("Token type = %d", int(token));

            // Parse value
            switch (token)
            {
                case osc::PT_FLOAT32:
                {
                    p.type      = KVT_FLOAT32;
                    res         = osc::parse_float32(&message, &p.f32);
                    break;
                }
                case osc::PT_INT32:
                {
                    p.type      = KVT_INT32;
                    res         = osc::parse_int32(&message, &p.i32);
                    break;
                }
                case osc::PT_OSC_STRING:
                case osc::PT_NULL:
                {
                    p.type      = KVT_STRING;
                    res         = osc::parse_string(&message, &p.str);
                    if (res != STATUS_OK)
                        break;

                    // Try to look up for blob
                    if ((res = osc::parse_token(&message, &token)) != STATUS_OK)
                        break;
                    if (token == osc::PT_OSC_BLOB)
                    {
                        p.blob.ctype    = p.str;
                        res             = osc::parse_blob(&message, &p.blob.data, &p.blob.size);
                    }
                    break;
                }
                case osc::PT_INT64:
                {
                    p.type      = KVT_INT64;
                    res         = osc::parse_int64(&message, &p.i64);
                    break;
                }
                case osc::PT_DOUBLE64:
                {
                    p.type      = KVT_FLOAT64;
                    res         = osc::parse_double64(&message, &p.f64);
                    break;
                }
                case osc::PT_OSC_BLOB:
                {
                    p.type      = KVT_BLOB;
                    res         = osc::parse_blob(&message, &p.blob.data, &p.blob.size);
                    if (res != STATUS_OK)
                        break;

                    // Try to parse content type
                    if ((res = osc::parse_token(&message, &token)) != STATUS_OK)
                        break;
                    if (token == osc::PT_OSC_STRING)
                        res = osc::parse_string(&message, &p.blob.ctype);
                    else if (token == osc::PT_NULL)
                    {
                        res = osc::parse_skip(&message);
                        p.blob.ctype    = NULL;
                    }
                    break;
                }
                default:
                    lsp_trace("Unknown token");
                    res     = STATUS_BAD_TYPE;
                    break;
            }

            // Require end of message, and only then update KVT parameter value
            if (res == STATUS_OK)
            {
                kvt_dump_parameter("Parsed parameter: %s = ", &p, address);
                if ((res = osc::parse_token(&message, &token)) == STATUS_OK)
                {
                    if (token == osc::PT_EOR)
                    {
                        lsp_trace("Message has been fully read, submitting to KVT");

                        // Put the change to the KVT storage with RX/TX flags set
                        // We can freely use the address pointer while the pPacket is valid
                        res = kvt->put(address, &p, flags);
                    }
                }
            }

            // Finalize the message parser
            osc::parse_end(&message);
            osc::parse_end(&root);
            osc::parse_destroy(&parser);

            return res;
        }

        status_t KVTDispatcher::parse_message(KVTStorage *kvt, const osc::packet_t *packet, size_t flags)
        {
            return parse_message(kvt, packet->data, packet->size, flags);
        }

        status_t KVTDispatcher::build_message(const char *kvt_name, const kvt_param_t *p, void *data, size_t *size, size_t limit)
        {
            status_t res;
            osc::forge_t forge;
            osc::forge_frame_t root, message;
            osc::packet_t packet;

            // Serialize message
            res = osc::forge_begin_fixed(&root, &forge, data, limit);
            if (res != STATUS_OK)
                return res;

            res = osc::forge_begin_message(&message, &root, "/KVT", kvt_name);
            if (res != STATUS_OK)
            {
                osc::forge_end(&root);
                osc::forge_close(&packet, &forge);
                osc::forge_destroy(&forge);
                return res;
            }

            switch (p->type)
            {
                case KVT_INT32:
                    res = osc::forge_int32(&message, p->i32);
                    break;
                case KVT_UINT32:
                    res = osc::forge_int32(&message, p->u32);
                    break;
                case KVT_INT64:
                    res = osc::forge_int64(&message, p->i64);
                    break;
                case KVT_UINT64:
                    res = osc::forge_int64(&message, p->u64);
                    break;
                case KVT_FLOAT32:
                    res = osc::forge_float32(&message, p->f32);
                    break;
                case KVT_FLOAT64:
                    res = osc::forge_double64(&message, p->f64);
                    break;
                case KVT_STRING:
                    res = osc::forge_string(&message, p->str);
                    break;
                case KVT_BLOB:
                    res = osc::forge_string(&message, p->blob.ctype);
                    if (res == STATUS_OK)
                        res = osc::forge_blob(&message, p->blob.data, p->blob.size);
                    break;
                default:
                    res = STATUS_BAD_TYPE;
                    break;
            }

            osc::forge_end(&message);
            osc::forge_end(&root);
            osc::forge_close(&packet, &forge);
            osc::forge_destroy(&forge);

            *size   = packet.size;
            return res;
        }

        status_t KVTDispatcher::build_message(const char *param_name, const kvt_param_t *param, osc::packet_t *packet, size_t limit)
        {
            return build_message(param_name, param, &packet->data, &packet->size, limit);
        }

    } /* namespace core */
} /* namespace lsp */



