/**
 * OpenAL cross platform audio library
 * Copyright (C) 1999-2007 by authors.
 * This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 *  Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 *  License along with this library; if not, write to the
 *  Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 * Or go to http://www.gnu.org/copyleft/lgpl.html
 */

#include "config.h"

#include "backends/jack.h"

#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <memory.h>

#include <array>
#include <thread>
#include <functional>

#include "alcmain.h"
#include "alu.h"
#include "alconfig.h"
#include "alexcpt.h"
#include "core/logging.h"
#include "dynload.h"
#include "ringbuffer.h"
#include "threads.h"

#include <jack/jack.h>
#include <jack/ringbuffer.h>


namespace {

constexpr char jackDevice[] = "JACK Default";


#ifdef HAVE_DYNLOAD
#define JACK_FUNCS(MAGIC)          \
    MAGIC(jack_client_open);       \
    MAGIC(jack_client_close);      \
    MAGIC(jack_client_name_size);  \
    MAGIC(jack_get_client_name);   \
    MAGIC(jack_connect);           \
    MAGIC(jack_activate);          \
    MAGIC(jack_deactivate);        \
    MAGIC(jack_port_register);     \
    MAGIC(jack_port_unregister);   \
    MAGIC(jack_port_get_buffer);   \
    MAGIC(jack_port_name);         \
    MAGIC(jack_get_ports);         \
    MAGIC(jack_free);              \
    MAGIC(jack_get_sample_rate);   \
    MAGIC(jack_set_error_function); \
    MAGIC(jack_set_process_callback); \
    MAGIC(jack_set_buffer_size_callback); \
    MAGIC(jack_set_buffer_size);   \
    MAGIC(jack_get_buffer_size);

void *jack_handle;
#define MAKE_FUNC(f) decltype(f) * p##f
JACK_FUNCS(MAKE_FUNC);
decltype(jack_error_callback) * pjack_error_callback;
#undef MAKE_FUNC

#ifndef IN_IDE_PARSER
#define jack_client_open pjack_client_open
#define jack_client_close pjack_client_close
#define jack_client_name_size pjack_client_name_size
#define jack_get_client_name pjack_get_client_name
#define jack_connect pjack_connect
#define jack_activate pjack_activate
#define jack_deactivate pjack_deactivate
#define jack_port_register pjack_port_register
#define jack_port_unregister pjack_port_unregister
#define jack_port_get_buffer pjack_port_get_buffer
#define jack_port_name pjack_port_name
#define jack_get_ports pjack_get_ports
#define jack_free pjack_free
#define jack_get_sample_rate pjack_get_sample_rate
#define jack_set_error_function pjack_set_error_function
#define jack_set_process_callback pjack_set_process_callback
#define jack_set_buffer_size_callback pjack_set_buffer_size_callback
#define jack_set_buffer_size pjack_set_buffer_size
#define jack_get_buffer_size pjack_get_buffer_size
#define jack_error_callback (*pjack_error_callback)
#endif
#endif


jack_options_t ClientOptions = JackNullOption;

bool jack_load()
{
    bool error{false};

#ifdef HAVE_DYNLOAD
    if(!jack_handle)
    {
        std::string missing_funcs;

#ifdef _WIN32
#define JACKLIB "libjack.dll"
#else
#define JACKLIB "libjack.so.0"
#endif
        jack_handle = LoadLib(JACKLIB);
        if(!jack_handle)
        {
            WARN("Failed to load %s\n", JACKLIB);
            return false;
        }

        error = false;
#define LOAD_FUNC(f) do {                                                     \
    p##f = reinterpret_cast<decltype(p##f)>(GetSymbol(jack_handle, #f));      \
    if(p##f == nullptr) {                                                     \
        error = true;                                                         \
        missing_funcs += "\n" #f;                                             \
    }                                                                         \
} while(0)
        JACK_FUNCS(LOAD_FUNC);
#undef LOAD_FUNC
        /* Optional symbols. These don't exist in all versions of JACK. */
#define LOAD_SYM(f) p##f = reinterpret_cast<decltype(p##f)>(GetSymbol(jack_handle, #f))
        LOAD_SYM(jack_error_callback);
#undef LOAD_SYM

        if(error)
        {
            WARN("Missing expected functions:%s\n", missing_funcs.c_str());
            CloseLib(jack_handle);
            jack_handle = nullptr;
        }
    }
#endif

    return !error;
}


struct DeviceEntry {
    std::string mName;
    std::string mPattern;
};

al::vector<DeviceEntry> PlaybackList;


void EnumerateDevices(al::vector<DeviceEntry> &list)
{
    al::vector<DeviceEntry>{}.swap(list);

    list.emplace_back(DeviceEntry{jackDevice, ""});

    std::string customList{ConfigValueStr(nullptr, "jack", "custom-devices").value_or("")};
    size_t strpos{0};
    while(strpos < customList.size())
    {
        size_t nextpos{customList.find(';', strpos)};
        size_t seppos{customList.find('=', strpos)};
        if(seppos >= nextpos || seppos == strpos)
        {
            const std::string entry{customList.substr(strpos, nextpos-strpos)};
            ERR("Invalid device entry: \"%s\"\n", entry.c_str());
            if(nextpos != std::string::npos) ++nextpos;
            strpos = nextpos;
            continue;
        }

        size_t count{1};
        std::string name{customList.substr(strpos, seppos-strpos)};
        auto check_name = [&name](const DeviceEntry &entry) -> bool
        { return entry.mName == name; };
        while(std::find_if(list.cbegin(), list.cend(), check_name) != list.cend())
        {
            name = customList.substr(strpos, seppos-strpos);
            name += " #";
            name += std::to_string(++count);
        }

        ++seppos;
        list.emplace_back(DeviceEntry{std::move(name), customList.substr(seppos, nextpos-seppos)});
        const auto &entry = list.back();
        TRACE("Got custom device: %s = %s\n", entry.mName.c_str(), entry.mPattern.c_str());

        if(nextpos != std::string::npos) ++nextpos;
        strpos = nextpos;
    }
}


struct JackPlayback final : public BackendBase {
    JackPlayback(ALCdevice *device) noexcept : BackendBase{device} { }
    ~JackPlayback() override;

    int process(jack_nframes_t numframes) noexcept;
    static int processC(jack_nframes_t numframes, void *arg) noexcept
    { return static_cast<JackPlayback*>(arg)->process(numframes); }

    int mixerProc();

    void open(const char *name) override;
    bool reset() override;
    void start() override;
    void stop() override;
    ClockLatency getClockLatency() override;

    std::string mPortPattern;

    jack_client_t *mClient{nullptr};
    std::array<jack_port_t*,MAX_OUTPUT_CHANNELS> mPort{};

    std::mutex mMutex;

    std::atomic<bool> mPlaying{false};
    RingBufferPtr mRing;
    al::semaphore mSem;

    std::atomic<bool> mKillNow{true};
    std::thread mThread;

    DEF_NEWDEL(JackPlayback)
};

JackPlayback::~JackPlayback()
{
    if(!mClient)
        return;

    std::for_each(mPort.begin(), mPort.end(),
        [this](jack_port_t *port) -> void
        { if(port) jack_port_unregister(mClient, port); }
    );
    mPort.fill(nullptr);
    jack_client_close(mClient);
    mClient = nullptr;
}


int JackPlayback::process(jack_nframes_t numframes) noexcept
{
    std::array<jack_default_audio_sample_t*,MAX_OUTPUT_CHANNELS> out;
    size_t numchans{0};
    for(auto port : mPort)
    {
        if(!port) break;
        out[numchans++] = static_cast<float*>(jack_port_get_buffer(port, numframes));
    }

    jack_nframes_t total{0};
    if LIKELY(mPlaying.load(std::memory_order_acquire))
    {
        auto data = mRing->getReadVector();
        jack_nframes_t todo{minu(numframes, static_cast<uint>(data.first.len))};
        auto write_first = [&data,numchans,todo](float *outbuf) -> float*
        {
            const float *RESTRICT in = reinterpret_cast<float*>(data.first.buf);
            auto deinterlace_input = [&in,numchans]() noexcept -> float
            {
                float ret{*in};
                in += numchans;
                return ret;
            };
            std::generate_n(outbuf, todo, deinterlace_input);
            data.first.buf += sizeof(float);
            return outbuf + todo;
        };
        std::transform(out.begin(), out.begin()+numchans, out.begin(), write_first);
        total += todo;

        todo = minu(numframes-total, static_cast<uint>(data.second.len));
        if(todo > 0)
        {
            auto write_second = [&data,numchans,todo](float *outbuf) -> float*
            {
                const float *RESTRICT in = reinterpret_cast<float*>(data.second.buf);
                auto deinterlace_input = [&in,numchans]() noexcept -> float
                {
                    float ret{*in};
                    in += numchans;
                    return ret;
                };
                std::generate_n(outbuf, todo, deinterlace_input);
                data.second.buf += sizeof(float);
                return outbuf + todo;
            };
            std::transform(out.begin(), out.begin()+numchans, out.begin(), write_second);
            total += todo;
        }

        mRing->readAdvance(total);
        mSem.post();
    }

    if(numframes > total)
    {
        const jack_nframes_t todo{numframes - total};
        auto clear_buf = [todo](float *outbuf) -> void { std::fill_n(outbuf, todo, 0.0f); };
        std::for_each(out.begin(), out.begin()+numchans, clear_buf);
    }

    return 0;
}

int JackPlayback::mixerProc()
{
    SetRTPriority();
    althrd_setname(MIXER_THREAD_NAME);

    const size_t frame_step{mDevice->channelsFromFmt()};

    while(!mKillNow.load(std::memory_order_acquire)
        && mDevice->Connected.load(std::memory_order_acquire))
    {
        if(mRing->writeSpace() < mDevice->UpdateSize)
        {
            mSem.wait();
            continue;
        }

        auto data = mRing->getWriteVector();
        size_t todo{data.first.len + data.second.len};
        todo -= todo%mDevice->UpdateSize;

        const auto len1 = static_cast<uint>(minz(data.first.len, todo));
        const auto len2 = static_cast<uint>(minz(data.second.len, todo-len1));

        std::lock_guard<std::mutex> _{mMutex};
        mDevice->renderSamples(data.first.buf, len1, frame_step);
        if(len2 > 0)
            mDevice->renderSamples(data.second.buf, len2, frame_step);
        mRing->writeAdvance(todo);
    }

    return 0;
}


void JackPlayback::open(const char *name)
{
    mPortPattern.clear();

    if(!name)
        name = jackDevice;
    else if(strcmp(name, jackDevice) != 0)
    {
        if(PlaybackList.empty())
            EnumerateDevices(PlaybackList);

        auto check_name = [name](const DeviceEntry &entry) -> bool
        { return entry.mName == name; };
        auto iter = std::find_if(PlaybackList.cbegin(), PlaybackList.cend(), check_name);
        if(iter == PlaybackList.cend())
            throw al::backend_exception{al::backend_error::NoDevice,
                "Device name \"%s\" not found", name};
        mPortPattern = iter->mPattern;
    }

    const char *client_name{"alsoft"};
    jack_status_t status;
    mClient = jack_client_open(client_name, ClientOptions, &status, nullptr);
    if(mClient == nullptr)
        throw al::backend_exception{al::backend_error::DeviceError,
            "Failed to open client connection: 0x%02x", status};

    if((status&JackServerStarted))
        TRACE("JACK server started\n");
    if((status&JackNameNotUnique))
    {
        client_name = jack_get_client_name(mClient);
        TRACE("Client name not unique, got '%s' instead\n", client_name);
    }

    jack_set_process_callback(mClient, &JackPlayback::processC, this);

    mDevice->DeviceName = name;
}

bool JackPlayback::reset()
{
    std::for_each(mPort.begin(), mPort.end(),
        [this](jack_port_t *port) -> void
        { if(port) jack_port_unregister(mClient, port); });
    mPort.fill(nullptr);

    /* Ignore the requested buffer metrics and just keep one JACK-sized buffer
     * ready for when requested.
     */
    mDevice->Frequency = jack_get_sample_rate(mClient);
    mDevice->UpdateSize = jack_get_buffer_size(mClient);
    mDevice->BufferSize = mDevice->UpdateSize * 2;

    const char *devname{mDevice->DeviceName.c_str()};
    uint bufsize{ConfigValueUInt(devname, "jack", "buffer-size").value_or(mDevice->UpdateSize)};
    bufsize = maxu(NextPowerOf2(bufsize), mDevice->UpdateSize);
    mDevice->BufferSize = bufsize + mDevice->UpdateSize;

    /* Force 32-bit float output. */
    mDevice->FmtType = DevFmtFloat;

    auto ports_end = mPort.begin() + mDevice->channelsFromFmt();
    auto bad_port = std::find_if_not(mPort.begin(), ports_end,
        [this](jack_port_t *&port) -> bool
        {
            std::string name{"channel_" + std::to_string(&port - &mPort[0] + 1)};
            port = jack_port_register(mClient, name.c_str(), JACK_DEFAULT_AUDIO_TYPE,
                JackPortIsOutput, 0);
            return port != nullptr;
        });
    if(bad_port != ports_end)
    {
        ERR("Not enough JACK ports available for %s output\n", DevFmtChannelsString(mDevice->FmtChans));
        if(bad_port == mPort.begin()) return false;

        if(bad_port == mPort.begin()+1)
            mDevice->FmtChans = DevFmtMono;
        else
        {
            ports_end = mPort.begin()+2;
            while(bad_port != ports_end)
            {
                jack_port_unregister(mClient, *(--bad_port));
                *bad_port = nullptr;
            }
            mDevice->FmtChans = DevFmtStereo;
        }
    }

    setDefaultChannelOrder();

    return true;
}

void JackPlayback::start()
{
    if(jack_activate(mClient))
        throw al::backend_exception{al::backend_error::DeviceError, "Failed to activate client"};

    const char *devname{mDevice->DeviceName.c_str()};
    if(ConfigValueBool(devname, "jack", "connect-ports").value_or(true))
    {
        const char **ports{jack_get_ports(mClient, mPortPattern.c_str(), nullptr,
            JackPortIsPhysical|JackPortIsInput)};
        if(ports == nullptr)
        {
            jack_deactivate(mClient);
            throw al::backend_exception{al::backend_error::DeviceError,
                "No physical playback ports found"};
        }
        auto connect_port = [this](const jack_port_t *port, const char *pname) -> bool
        {
            if(!port) return false;
            if(!pname)
            {
                ERR("No physical playback port for \"%s\"\n", jack_port_name(port));
                return false;
            }
            if(jack_connect(mClient, jack_port_name(port), pname))
                ERR("Failed to connect output port \"%s\" to \"%s\"\n", jack_port_name(port),
                    pname);
            return true;
        };
        std::mismatch(mPort.begin(), mPort.end(), ports, connect_port);
        jack_free(ports);
    }

    /* Reconfigure buffer metrics in case the server changed it since the reset
     * (it won't change again after jack_activate), then allocate the ring
     * buffer with the appropriate size.
     */
    mDevice->Frequency = jack_get_sample_rate(mClient);
    mDevice->UpdateSize = jack_get_buffer_size(mClient);
    mDevice->BufferSize = mDevice->UpdateSize * 2;

    uint bufsize{ConfigValueUInt(devname, "jack", "buffer-size").value_or(mDevice->UpdateSize)};
    bufsize = maxu(NextPowerOf2(bufsize), mDevice->UpdateSize);
    mDevice->BufferSize = bufsize + mDevice->UpdateSize;

    mRing = nullptr;
    mRing = RingBuffer::Create(bufsize, mDevice->frameSizeFromFmt(), true);

    try {
        mPlaying.store(true, std::memory_order_release);
        mKillNow.store(false, std::memory_order_release);
        mThread = std::thread{std::mem_fn(&JackPlayback::mixerProc), this};
    }
    catch(std::exception& e) {
        jack_deactivate(mClient);
        mPlaying.store(false, std::memory_order_release);
        throw al::backend_exception{al::backend_error::DeviceError,
            "Failed to start mixing thread: %s", e.what()};
    }
}

void JackPlayback::stop()
{
    if(mKillNow.exchange(true, std::memory_order_acq_rel) || !mThread.joinable())
        return;

    mSem.post();
    mThread.join();

    jack_deactivate(mClient);
    mPlaying.store(false, std::memory_order_release);
}


ClockLatency JackPlayback::getClockLatency()
{
    ClockLatency ret;

    std::lock_guard<std::mutex> _{mMutex};
    ret.ClockTime = GetDeviceClockTime(mDevice);
    ret.Latency  = std::chrono::seconds{mRing->readSpace()};
    ret.Latency /= mDevice->Frequency;

    return ret;
}


void jack_msg_handler(const char *message)
{
    WARN("%s\n", message);
}

} // namespace

bool JackBackendFactory::init()
{
    if(!jack_load())
        return false;

    if(!GetConfigValueBool(nullptr, "jack", "spawn-server", 0))
        ClientOptions = static_cast<jack_options_t>(ClientOptions | JackNoStartServer);

    void (*old_error_cb)(const char*){&jack_error_callback ? jack_error_callback : nullptr};
    jack_set_error_function(jack_msg_handler);
    jack_status_t status;
    jack_client_t *client{jack_client_open("alsoft", ClientOptions, &status, nullptr)};
    jack_set_error_function(old_error_cb);
    if(!client)
    {
        WARN("jack_client_open() failed, 0x%02x\n", status);
        if((status&JackServerFailed) && !(ClientOptions&JackNoStartServer))
            ERR("Unable to connect to JACK server\n");
        return false;
    }

    jack_client_close(client);
    return true;
}

bool JackBackendFactory::querySupport(BackendType type)
{ return (type == BackendType::Playback); }

std::string JackBackendFactory::probe(BackendType type)
{
    std::string outnames;
    auto append_name = [&outnames](const DeviceEntry &entry) -> void
    {
        /* Includes null char. */
        outnames.append(entry.mName.c_str(), entry.mName.length()+1);
    };
    switch(type)
    {
    case BackendType::Playback:
        EnumerateDevices(PlaybackList);
        std::for_each(PlaybackList.cbegin(), PlaybackList.cend(), append_name);
        break;
    case BackendType::Capture:
        break;
    }
    return outnames;
}

BackendPtr JackBackendFactory::createBackend(ALCdevice *device, BackendType type)
{
    if(type == BackendType::Playback)
        return BackendPtr{new JackPlayback{device}};
    return nullptr;
}

BackendFactory &JackBackendFactory::getFactory()
{
    static JackBackendFactory factory{};
    return factory;
}