/*
  ==============================================================================

   This file is part of the JUCE framework.
   Copyright (c) Raw Material Software Limited

   JUCE is an open source framework subject to commercial or open source
   licensing.

   By downloading, installing, or using the JUCE framework, or combining the
   JUCE framework with any other source code, object code, content or any other
   copyrightable work, you agree to the terms of the JUCE End User Licence
   Agreement, and all incorporated terms including the JUCE Privacy Policy and
   the JUCE Website Terms of Service, as applicable, which will bind you. If you
   do not agree to the terms of these agreements, we will not license the JUCE
   framework to you, and you must discontinue the installation or download
   process and cease use of the JUCE framework.

   JUCE End User Licence Agreement: https://juce.com/legal/juce-8-licence/
   JUCE Privacy Policy: https://juce.com/juce-privacy-policy
   JUCE Website Terms of Service: https://juce.com/juce-website-terms-of-service/

   Or:

   You may also use this code under the terms of the AGPLv3:
   https://www.gnu.org/licenses/agpl-3.0.en.html

   THE JUCE FRAMEWORK IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL
   WARRANTIES, WHETHER EXPRESSED OR IMPLIED, INCLUDING WARRANTY OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

static void* juce_libjackHandle = nullptr;

static void* juce_loadJackFunction (const char* const name)
{
    if (juce_libjackHandle == nullptr)
        return nullptr;

    return dlsym (juce_libjackHandle, name);
}

#define JUCE_DECL_JACK_FUNCTION(return_type, fn_name, argument_types, arguments)  \
  return_type fn_name argument_types                                              \
  {                                                                               \
      using ReturnType = return_type;                                             \
      typedef return_type (*fn_type) argument_types;                              \
      static fn_type fn = (fn_type) juce_loadJackFunction (#fn_name);             \
      jassert (fn != nullptr);                                                    \
      return (fn != nullptr) ? ((*fn) arguments) : ReturnType();                  \
  }

#define JUCE_DECL_VOID_JACK_FUNCTION(fn_name, argument_types, arguments)          \
  void fn_name argument_types                                                     \
  {                                                                               \
      typedef void (*fn_type) argument_types;                                     \
      static fn_type fn = (fn_type) juce_loadJackFunction (#fn_name);             \
      jassert (fn != nullptr);                                                    \
      if (fn != nullptr) (*fn) arguments;                                         \
  }

//==============================================================================
JUCE_DECL_JACK_FUNCTION (jack_client_t*, jack_client_open, (const char* client_name, jack_options_t options, jack_status_t* status, ...), (client_name, options, status))
JUCE_DECL_JACK_FUNCTION (int, jack_client_close, (jack_client_t *client), (client))
JUCE_DECL_JACK_FUNCTION (int, jack_activate, (jack_client_t* client), (client))
JUCE_DECL_JACK_FUNCTION (int, jack_deactivate, (jack_client_t* client), (client))
JUCE_DECL_JACK_FUNCTION (jack_nframes_t, jack_get_buffer_size, (jack_client_t* client), (client))
JUCE_DECL_JACK_FUNCTION (jack_nframes_t, jack_get_sample_rate, (jack_client_t* client), (client))
JUCE_DECL_VOID_JACK_FUNCTION (jack_on_shutdown, (jack_client_t* client, void (*function) (void* arg), void* arg), (client, function, arg))
JUCE_DECL_VOID_JACK_FUNCTION (jack_on_info_shutdown, (jack_client_t* client, JackInfoShutdownCallback function, void* arg), (client, function, arg))
JUCE_DECL_JACK_FUNCTION (void* , jack_port_get_buffer, (jack_port_t* port, jack_nframes_t nframes), (port, nframes))
JUCE_DECL_JACK_FUNCTION (jack_nframes_t, jack_port_get_total_latency, (jack_client_t* client, jack_port_t* port), (client, port))
JUCE_DECL_JACK_FUNCTION (jack_port_t* , jack_port_register, (jack_client_t* client, const char* port_name, const char* port_type, unsigned long flags, unsigned long buffer_size), (client, port_name, port_type, flags, buffer_size))
JUCE_DECL_VOID_JACK_FUNCTION (jack_set_error_function, (void (*func) (const char*)), (func))
JUCE_DECL_JACK_FUNCTION (int, jack_set_process_callback, (jack_client_t* client, JackProcessCallback process_callback, void* arg), (client, process_callback, arg))
JUCE_DECL_JACK_FUNCTION (const char**, jack_get_ports, (jack_client_t* client, const char* port_name_pattern, const char* type_name_pattern, unsigned long flags), (client, port_name_pattern, type_name_pattern, flags))
JUCE_DECL_JACK_FUNCTION (int, jack_connect, (jack_client_t* client, const char* source_port, const char* destination_port), (client, source_port, destination_port))
JUCE_DECL_JACK_FUNCTION (const char*, jack_port_name, (const jack_port_t* port), (port))
JUCE_DECL_JACK_FUNCTION (void*, jack_set_port_connect_callback, (jack_client_t* client, JackPortConnectCallback connect_callback, void* arg), (client, connect_callback, arg))
JUCE_DECL_JACK_FUNCTION (jack_port_t* , jack_port_by_id, (jack_client_t* client, jack_port_id_t port_id), (client, port_id))
JUCE_DECL_JACK_FUNCTION (int, jack_port_connected, (const jack_port_t* port), (port))
JUCE_DECL_JACK_FUNCTION (int, jack_port_connected_to, (const jack_port_t* port, const char* port_name), (port, port_name))
JUCE_DECL_JACK_FUNCTION (int, jack_set_xrun_callback, (jack_client_t* client, JackXRunCallback xrun_callback, void* arg), (client, xrun_callback, arg))
JUCE_DECL_JACK_FUNCTION (int, jack_port_flags, (const jack_port_t* port), (port))
JUCE_DECL_JACK_FUNCTION (jack_port_t*, jack_port_by_name, (jack_client_t* client, const char* name), (client, name))
JUCE_DECL_VOID_JACK_FUNCTION (jack_free, (void* ptr), (ptr))

#if JUCE_DEBUG
 #define JACK_LOGGING_ENABLED 1
#endif

#if JACK_LOGGING_ENABLED
namespace
{
    void jack_Log (const String& s)
    {
        std::cerr << s << std::endl;
    }

    const char* getJackErrorMessage (const jack_status_t status)
    {
        if (status & JackServerFailed
             || status & JackServerError)   return "Unable to connect to JACK server";
        if (status & JackVersionError)      return "Client's protocol version does not match";
        if (status & JackInvalidOption)     return "The operation contained an invalid or unsupported option";
        if (status & JackNameNotUnique)     return "The desired client name was not unique";
        if (status & JackNoSuchClient)      return "Requested client does not exist";
        if (status & JackInitFailure)       return "Unable to initialize client";
        return nullptr;
    }
}
 #define JUCE_JACK_LOG_STATUS(x)    { if (const char* m = getJackErrorMessage (x)) jack_Log (m); }
 #define JUCE_JACK_LOG(x)           jack_Log(x)
#else
 #define JUCE_JACK_LOG_STATUS(x)    {}
 #define JUCE_JACK_LOG(x)           {}
#endif


//==============================================================================
#ifndef JUCE_JACK_CLIENT_NAME
 #ifdef JucePlugin_Name
  #define JUCE_JACK_CLIENT_NAME JucePlugin_Name
 #else
  #define JUCE_JACK_CLIENT_NAME "JUCEJack"
 #endif
#endif

struct JackPortIterator
{
    JackPortIterator (jack_client_t* const client, const bool forInput)
    {
        if (client != nullptr)
            ports.reset (juce::jack_get_ports (client, nullptr, nullptr,
                                               forInput ? JackPortIsInput : JackPortIsOutput));
    }

    bool next()
    {
        if (ports == nullptr || ports.get()[index + 1] == nullptr)
            return false;

        name = CharPointer_UTF8 (ports.get()[++index]);
        return true;
    }

    String getClientName() const
    {
        return name.upToFirstOccurrenceOf (":", false, false);
    }

    String getChannelName() const
    {
        return name.fromFirstOccurrenceOf (":", false, false);
    }

    struct Free
    {
        void operator() (const char** ptr) const noexcept { juce::jack_free (ptr); }
    };

    std::unique_ptr<const char*, Free> ports;
    int index = -1;
    String name;
};

//==============================================================================
class JackAudioIODevice final : public AudioIODevice
{
public:
    JackAudioIODevice (const String& inName,
                       const String& outName,
                       std::function<void()> notifyIn)
        : AudioIODevice (outName.isEmpty() ? inName : outName, "JACK"),
          inputName (inName),
          outputName (outName),
          notifyChannelsChanged (std::move (notifyIn))
    {
        jassert (outName.isNotEmpty() || inName.isNotEmpty());

        jack_status_t status = {};
        client = juce::jack_client_open (JUCE_JACK_CLIENT_NAME, JackNoStartServer, &status);

        if (client == nullptr)
        {
            JUCE_JACK_LOG_STATUS (status);
        }
        else
        {
            juce::jack_set_error_function (errorCallback);

            // open input ports
            const StringArray inputChannels (getInputChannelNames());
            for (int i = 0; i < inputChannels.size(); ++i)
            {
                String inputChannelName;
                inputChannelName << "in_" << ++totalNumberOfInputChannels;

                inputPorts.add (juce::jack_port_register (client, inputChannelName.toUTF8(),
                                                          JACK_DEFAULT_AUDIO_TYPE, JackPortIsInput, 0));
            }

            // open output ports
            const StringArray outputChannels (getOutputChannelNames());
            for (int i = 0; i < outputChannels.size(); ++i)
            {
                String outputChannelName;
                outputChannelName << "out_" << ++totalNumberOfOutputChannels;

                outputPorts.add (juce::jack_port_register (client, outputChannelName.toUTF8(),
                                                           JACK_DEFAULT_AUDIO_TYPE, JackPortIsOutput, 0));
            }

            inChans.calloc (totalNumberOfInputChannels + 2);
            outChans.calloc (totalNumberOfOutputChannels + 2);
        }
    }

    ~JackAudioIODevice() override
    {
        close();
        if (client != nullptr)
        {
            juce::jack_client_close (client);
            client = nullptr;
        }
    }

    StringArray getChannelNames (const String& clientName, bool forInput) const
    {
        StringArray names;

        for (JackPortIterator i (client, forInput); i.next();)
            if (i.getClientName() == clientName)
                names.add (i.getChannelName());

        return names;
    }

    StringArray getOutputChannelNames() override         { return getChannelNames (outputName, true); }
    StringArray getInputChannelNames() override          { return getChannelNames (inputName, false); }

    Array<double> getAvailableSampleRates() override
    {
        Array<double> rates;

        if (client != nullptr)
            rates.add (juce::jack_get_sample_rate (client));

        return rates;
    }

    Array<int> getAvailableBufferSizes() override
    {
        Array<int> sizes;

        if (client != nullptr)
            sizes.add (static_cast<int> (juce::jack_get_buffer_size (client)));

        return sizes;
    }

    int getDefaultBufferSize() override             { return getCurrentBufferSizeSamples(); }
    int getCurrentBufferSizeSamples() override      { return client != nullptr ? static_cast<int> (juce::jack_get_buffer_size (client)) : 0; }
    double getCurrentSampleRate() override          { return client != nullptr ? static_cast<int> (juce::jack_get_sample_rate (client)) : 0; }

    template <typename Fn>
    void forEachClientChannel (const String& clientName, bool isInput, Fn&& fn)
    {
        auto index = 0;

        for (JackPortIterator i (client, isInput); i.next();)
        {
            if (i.getClientName() != clientName)
                continue;

            fn (i.ports.get()[i.index], index);
            index += 1;
        }
    }

    String open (const BigInteger& inputChannels, const BigInteger& outputChannels,
                 double /* sampleRate */, int /* bufferSizeSamples */) override
    {
        if (client == nullptr)
        {
            lastError = "No JACK client running";
            return lastError;
        }

        lastError.clear();
        close();

        xruns.store (0, std::memory_order_relaxed);
        juce::jack_set_process_callback (client, processCallback, this);
        juce::jack_set_port_connect_callback (client, portConnectCallback, this);
        juce::jack_on_shutdown (client, shutdownCallback, this);
        juce::jack_on_info_shutdown (client, infoShutdownCallback, this);
        juce::jack_set_xrun_callback (client, xrunCallback, this);
        juce::jack_activate (client);
        deviceIsOpen = true;

        if (! inputChannels.isZero())
        {
            forEachClientChannel (inputName, false, [&] (const char* portName, int index)
            {
                if (! inputChannels[index])
                    return;

                jassert (index < inputPorts.size());

                const auto* source = portName;
                const auto* inputPort = inputPorts[index];

                jassert (juce::jack_port_flags (juce::jack_port_by_name (client, source)) & JackPortIsOutput);
                jassert (juce::jack_port_flags (inputPort) & JackPortIsInput);

                auto error = juce::jack_connect (client, source, juce::jack_port_name (inputPort));
                if (error != 0)
                    JUCE_JACK_LOG ("Cannot connect input port " + String (index) + " (" + portName + "), error " + String (error));
            });
        }

        if (! outputChannels.isZero())
        {
            forEachClientChannel (outputName, true, [&] (const char* portName, int index)
            {
                if (! outputChannels[index])
                    return;

                jassert (index < outputPorts.size());

                const auto* outputPort = outputPorts[index];
                const auto* destination = portName;

                jassert (juce::jack_port_flags (outputPort) & JackPortIsOutput);
                jassert (juce::jack_port_flags (juce::jack_port_by_name (client, destination)) & JackPortIsInput);

                auto error = juce::jack_connect (client, juce::jack_port_name (outputPort), destination);
                if (error != 0)
                    JUCE_JACK_LOG ("Cannot connect output port " + String (index) + " (" + portName + "), error " + String (error));
            });
        }

        updateActivePorts();

        return lastError;
    }

    void close() override
    {
        stop();

        if (client != nullptr)
        {
            [[maybe_unused]] const auto result = juce::jack_deactivate (client);
            jassert (result == 0);

            juce::jack_set_xrun_callback (client, xrunCallback, nullptr);
            juce::jack_set_process_callback (client, processCallback, nullptr);
            juce::jack_set_port_connect_callback (client, portConnectCallback, nullptr);
            juce::jack_on_shutdown (client, shutdownCallback, nullptr);
            juce::jack_on_info_shutdown (client, infoShutdownCallback, nullptr);
        }

        deviceIsOpen = false;
    }

    void start (AudioIODeviceCallback* newCallback) override
    {
        if (deviceIsOpen && newCallback != callback)
        {
            if (newCallback != nullptr)
                newCallback->audioDeviceAboutToStart (this);

            AudioIODeviceCallback* const oldCallback = callback;

            {
                const ScopedLock sl (callbackLock);
                callback = newCallback;
            }

            if (oldCallback != nullptr)
                oldCallback->audioDeviceStopped();
        }
    }

    void stop() override
    {
        start (nullptr);
    }

    bool isOpen() override                           { return deviceIsOpen; }
    bool isPlaying() override                        { return callback != nullptr; }
    int getCurrentBitDepth() override                { return 32; }
    String getLastError() override                   { return lastError; }
    int getXRunCount() const noexcept override       { return xruns.load (std::memory_order_relaxed); }

    BigInteger getActiveOutputChannels() const override  { return activeOutputChannels; }
    BigInteger getActiveInputChannels()  const override  { return activeInputChannels;  }

    int getOutputLatencyInSamples() override
    {
        int latency = 0;

        for (int i = 0; i < outputPorts.size(); i++)
            latency = jmax (latency, (int) juce::jack_port_get_total_latency (client, outputPorts[i]));

        return latency;
    }

    int getInputLatencyInSamples() override
    {
        int latency = 0;

        for (int i = 0; i < inputPorts.size(); i++)
            latency = jmax (latency, (int) juce::jack_port_get_total_latency (client, inputPorts[i]));

        return latency;
    }

    String inputName, outputName;

private:
    //==============================================================================
    class MainThreadDispatcher final : private AsyncUpdater
    {
    public:
        explicit MainThreadDispatcher (JackAudioIODevice& device)  : ref (device) {}
        ~MainThreadDispatcher() override { cancelPendingUpdate(); }

        void updateActivePorts()
        {
            if (MessageManager::getInstance()->isThisTheMessageThread())
                handleAsyncUpdate();
            else
                triggerAsyncUpdate();
        }

    private:
        void handleAsyncUpdate() override { ref.updateActivePorts(); }

        JackAudioIODevice& ref;
    };

    //==============================================================================
    void process (const int numSamples)
    {
        int numActiveInChans = 0, numActiveOutChans = 0;

        for (int i = 0; i < totalNumberOfInputChannels; ++i)
        {
            if (activeInputChannels[i])
                if (auto* in = (jack_default_audio_sample_t*) juce::jack_port_get_buffer (inputPorts.getUnchecked (i),
                                                                                          static_cast<jack_nframes_t> (numSamples)))
                    inChans[numActiveInChans++] = (float*) in;
        }

        for (int i = 0; i < totalNumberOfOutputChannels; ++i)
        {
            if (activeOutputChannels[i])
                if (auto* out = (jack_default_audio_sample_t*) juce::jack_port_get_buffer (outputPorts.getUnchecked (i),
                                                                                           static_cast<jack_nframes_t> (numSamples)))
                    outChans[numActiveOutChans++] = (float*) out;
        }

        const ScopedLock sl (callbackLock);

        if (callback != nullptr)
        {
            if ((numActiveInChans + numActiveOutChans) > 0)
                callback->audioDeviceIOCallbackWithContext (inChans.getData(),
                                                            numActiveInChans,
                                                            outChans,
                                                            numActiveOutChans,
                                                            numSamples,
                                                            {});
        }
        else
        {
            for (int i = 0; i < numActiveOutChans; ++i)
                zeromem (outChans[i], static_cast<size_t> (numSamples) * sizeof (float));
        }
    }

    static int processCallback (jack_nframes_t nframes, void* callbackArgument)
    {
        if (callbackArgument != nullptr)
            ((JackAudioIODevice*) callbackArgument)->process (static_cast<int> (nframes));

        return 0;
    }

    static int xrunCallback (void* callbackArgument)
    {
        if (callbackArgument != nullptr)
            ((JackAudioIODevice*) callbackArgument)->xruns++;

        return 0;
    }

    void updateActivePorts()
    {
        BigInteger newOutputChannels, newInputChannels;

        for (int i = 0; i < outputPorts.size(); ++i)
            if (juce::jack_port_connected (outputPorts.getUnchecked (i)))
                newOutputChannels.setBit (i);

        for (int i = 0; i < inputPorts.size(); ++i)
            if (juce::jack_port_connected (inputPorts.getUnchecked (i)))
                newInputChannels.setBit (i);

        if (newOutputChannels != activeOutputChannels
             || newInputChannels != activeInputChannels)
        {
            AudioIODeviceCallback* const oldCallback = callback;

            stop();

            activeOutputChannels = newOutputChannels;
            activeInputChannels  = newInputChannels;

            if (oldCallback != nullptr)
                start (oldCallback);

            NullCheckedInvocation::invoke (notifyChannelsChanged);
        }
    }

    static void portConnectCallback (jack_port_id_t, jack_port_id_t, int, void* arg)
    {
        if (JackAudioIODevice* device = static_cast<JackAudioIODevice*> (arg))
            device->mainThreadDispatcher.updateActivePorts();
    }

    static void threadInitCallback (void* /* callbackArgument */)
    {
        JUCE_JACK_LOG ("JackAudioIODevice::initialise");
    }

    static void shutdownCallback (void* callbackArgument)
    {
        JUCE_JACK_LOG ("JackAudioIODevice::shutdown");

        if (JackAudioIODevice* device = (JackAudioIODevice*) callbackArgument)
        {
            device->client = nullptr;
            device->close();
        }
    }

    static void infoShutdownCallback ([[maybe_unused]] jack_status_t code, [[maybe_unused]] const char* reason, void* arg)
    {
        jassert (code == 0);

        JUCE_JACK_LOG ("Shutting down with message:");
        JUCE_JACK_LOG (reason);

        shutdownCallback (arg);
    }

    static void errorCallback ([[maybe_unused]] const char* msg)
    {
        JUCE_JACK_LOG ("JackAudioIODevice::errorCallback " + String (msg));
    }

    bool deviceIsOpen = false;
    jack_client_t* client = nullptr;
    String lastError;
    AudioIODeviceCallback* callback = nullptr;
    CriticalSection callbackLock;

    HeapBlock<float*> inChans, outChans;
    int totalNumberOfInputChannels = 0;
    int totalNumberOfOutputChannels = 0;
    Array<jack_port_t*> inputPorts, outputPorts;
    BigInteger activeInputChannels, activeOutputChannels;

    std::atomic<int> xruns { 0 };

    std::function<void()> notifyChannelsChanged;
    MainThreadDispatcher mainThreadDispatcher { *this };
};

//==============================================================================
class JackAudioIODeviceType;

class JackAudioIODeviceType final : public AudioIODeviceType
{
public:
    JackAudioIODeviceType()
        : AudioIODeviceType ("JACK")
    {}

    void scanForDevices()
    {
        hasScanned = true;
        inputNames.clear();
        outputNames.clear();

        if (juce_libjackHandle == nullptr)  juce_libjackHandle = dlopen ("libjack.so.0", RTLD_LAZY);
        if (juce_libjackHandle == nullptr)  juce_libjackHandle = dlopen ("libjack.so",   RTLD_LAZY);
        if (juce_libjackHandle == nullptr)  return;

        jack_status_t status = {};

        // open a dummy client
        if (auto* const client = juce::jack_client_open ("JuceJackDummy", JackNoStartServer, &status))
        {
            // scan for output devices
            for (JackPortIterator i (client, false); i.next();)
                if (i.getClientName() != (JUCE_JACK_CLIENT_NAME) && ! inputNames.contains (i.getClientName()))
                    inputNames.add (i.getClientName());

            // scan for input devices
            for (JackPortIterator i (client, true); i.next();)
                if (i.getClientName() != (JUCE_JACK_CLIENT_NAME) && ! outputNames.contains (i.getClientName()))
                    outputNames.add (i.getClientName());

            juce::jack_client_close (client);
        }
        else
        {
            JUCE_JACK_LOG_STATUS (status);
        }
    }

    StringArray getDeviceNames (bool wantInputNames) const
    {
        jassert (hasScanned); // need to call scanForDevices() before doing this
        return wantInputNames ? inputNames : outputNames;
    }

    int getDefaultDeviceIndex (bool /* forInput */) const
    {
        jassert (hasScanned); // need to call scanForDevices() before doing this
        return 0;
    }

    bool hasSeparateInputsAndOutputs() const    { return true; }

    int getIndexOfDevice (AudioIODevice* device, bool asInput) const
    {
        jassert (hasScanned); // need to call scanForDevices() before doing this

        if (JackAudioIODevice* d = dynamic_cast<JackAudioIODevice*> (device))
            return asInput ? inputNames.indexOf (d->inputName)
                           : outputNames.indexOf (d->outputName);

        return -1;
    }

    AudioIODevice* createDevice (const String& outputDeviceName,
                                 const String& inputDeviceName)
    {
        jassert (hasScanned); // need to call scanForDevices() before doing this

        const int inputIndex = inputNames.indexOf (inputDeviceName);
        const int outputIndex = outputNames.indexOf (outputDeviceName);

        if (inputIndex >= 0 || outputIndex >= 0)
            return new JackAudioIODevice (inputDeviceName, outputDeviceName,
                                          [this] { callDeviceChangeListeners(); });

        return nullptr;
    }

private:
    StringArray inputNames, outputNames;
    bool hasScanned = false;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (JackAudioIODeviceType)
};

} // namespace juce
