#include "Engine.h"
#include "RAVEButton.h"

namespace serum
{

namespace
{
    inline float limit (float x) noexcept
    {
        const float ax = std::fabs (x);
        if (ax < 0.8f)
            return x;
        const float over = ax - 0.8f;
        const float clipped = 0.8f + std::tanh (over) * 0.2f;
        return std::copysign (clipped, x);
    }
}

Engine::Engine()
{
    wavetables.prebuild();
    audioMatrix.connections.reserve (ModulationMatrix::kMaxConnections);
    for (auto& assignments : audioMacros.assignments)
        assignments.reserve (MacroControls::kMaxAssignments);
}

void Engine::prepare (double sampleRate, int maxBlockSize, juce::AudioProcessorValueTreeState& apvts)
{
    const juce::ScopedLock lock (controlLock);
    sr = sampleRate;
    blockSize = juce::jmax (1, maxBlockSize);
    parameterValues.clear();
    for (auto* parameter : apvts.processor.getParameters())
        if (auto* ranged = dynamic_cast<juce::RangedAudioParameter*> (parameter))
            if (auto* raw = apvts.getRawParameterValue (ranged->paramID))
                parameterValues.emplace (std::string_view (ranged->paramID.toRawUTF8()),
                                         ParameterValue { raw, raw->load() });

    for (auto& voice : voices)
        voice.prepare (sampleRate, blockSize);
    for (auto& lfo : lfos)
        lfo.prepare (sampleRate);
    fx.prepare (sampleRate, blockSize);
    mixBuffer.setSize (2, blockSize, false, false, true);
    reset();
    captureControls();
}

void Engine::reset()
{
    for (auto& voice : voices)
        voice.reset();
    for (auto& lfo : lfos)
        lfo.reset();
    fx.reset();
    pitchBend = 0.0f;
    modWheel  = 0.0f;
    activeVoiceCount.store (0, std::memory_order_relaxed);
    mixBuffer.clear();
}

void Engine::captureControls()
{
    const juce::ScopedTryLock lock (controlLock);
    if (! lock.isLocked())
        return;

    audioMatrix.connections.assign (matrix.connections.begin(),
        matrix.connections.begin() + juce::jmin (matrix.size(), ModulationMatrix::kMaxConnections));
    for (int i = 0; i < kNumMacros; ++i)
    {
        const auto& source = macros.assignments[(size_t) i];
        auto& dest = audioMacros.assignments[(size_t) i];
        dest.assign (source.begin(), source.begin() + juce::jmin ((int) source.size(), MacroControls::kMaxAssignments));
    }
    for (int i = 0; i < kNumLfos; ++i)
        lfos[(size_t) i].setShapeData (controlLfos[(size_t) i].getShapeData(),
                                      controlLfos[(size_t) i].getShapeSteps());
    for (auto& entry : parameterValues)
    {
        const float value = entry.second.source->load (std::memory_order_relaxed);
        entry.second.value = std::isfinite (value) ? juce::jlimit (0.0f, 1.0f, value) : 0.0f;
    }
}

void Engine::setLfoShapeData (int index, const std::vector<float>& data, int steps)
{
    const juce::ScopedLock lock (controlLock);
    index = juce::jlimit (0, kNumLfos - 1, index);
    controlLfos[(size_t) index].setShapeData (data, steps);
}

float Engine::v (const char* id) const
{
    const auto it = parameterValues.find (id);
    return it != parameterValues.end() ? it->second.value : 0.0f;
}

int Engine::vic (const char* id, int maxValue) const
{
    return juce::jlimit (0, maxValue, (int) std::llround (v (id) * maxValue));
}

SynthVoice* Engine::findFreeVoice()
{
    for (auto& voice : voices)
        if (! voice.isActive())
            return &voice;
    return nullptr;
}

SynthVoice* Engine::stealVoice()
{
    // Prefer stealing an already-released voice, then the oldest active one.
    SynthVoice* best = nullptr;
    juce::uint64 bestId = std::numeric_limits<juce::uint64>::max();

    for (auto& voice : voices)
        if (voice.isActive() && voice.isReleased() && voice.getNoteId() < bestId)
        {
            best = &voice;
            bestId = voice.getNoteId();
        }
    if (best != nullptr)
        return best;

    for (auto& voice : voices)
        if (voice.isActive() && voice.getNoteId() < bestId)
        {
            best = &voice;
            bestId = voice.getNoteId();
        }
    return best != nullptr ? best : &voices[0];
}

void Engine::noteOn (int noteNumber, float velocity01)
{
    SynthVoice* voice = findFreeVoice();
    if (voice == nullptr)
        voice = stealVoice();

    const double freq = juce::MidiMessage::getMidiNoteInHertz (noteNumber);
    voice->noteOn (noteNumber, juce::jlimit (0.0f, 1.0f, velocity01), freq, (juce::uint32) (++noteCounter));
}

void Engine::noteOff (int noteNumber)
{
    for (auto& voice : voices)
        if (voice.isActive() && voice.getNote() == noteNumber && ! voice.isReleased())
            voice.noteOff();
}

void Engine::allNotesOff()
{
    for (auto& voice : voices)
        if (voice.isActive())
            voice.noteOff();
}

void Engine::readOscParams (const paramIds::Oscillator& ids, OscParams& o) const
{
    o.enabled   = v (ids.on) > 0.5f;
    o.wave      = vic (ids.wave, kNumWavetables - 1);
    o.wtPos     = v (ids.wtPos);
    o.warp      = vic (ids.warp, (int) WarpMode::Count - 1);
    o.warpAmt   = v (ids.warpAmt);
    o.coarse    = vic (ids.coarse, 48) - 24;
    o.fine      = vic (ids.fine, 200) - 100;
    o.level     = v (ids.level);
    o.pan       = v (ids.pan) * 2.0f - 1.0f;
    o.unison    = 1 + vic (ids.unison, kMaxUnison - 1);
    o.detune    = v (ids.detune);
    o.spread    = v (ids.spread);
    o.phase     = v (ids.phase);
    o.randPhase = v (ids.randPhase);
}

void Engine::processBlock (juce::AudioBuffer<float>& buffer, juce::MidiBuffer& midi,
                           juce::AudioProcessorValueTreeState&, juce::AudioPlayHead* playhead)
{
    const int n = buffer.getNumSamples();
    const int numCh = buffer.getNumChannels();
    captureControls();

    // Tempo.
    if (playhead != nullptr)
        if (auto pos = playhead->getPosition())
            if (auto tempo = pos->getBpm())
                if (std::isfinite (*tempo) && *tempo > 0.0)
                    bpm = *tempo;

    // Advance LFOs and capture their values at control-rate render boundaries.
    for (int i = 0; i < kNumLfos; ++i)
    {
        auto& lfo = lfos[(size_t) i];
        lfo.setTempo (bpm);
        lfo.setParams (v (paramIds::lfoRate[i]), v (paramIds::lfoSync[i]) > 0.5f,
                       v (paramIds::lfoBeat[i]), vic (paramIds::lfoShape[i], (int) LfoShape::Count - 1),
                       v (paramIds::lfoPhase[i]), v (paramIds::lfoFade[i]), v (paramIds::lfoDelay[i]));
    }

    // Build the render context.
    RenderContext ctx;
    ctx.sampleRate = sr;
    ctx.wavetables = &wavetables;
    ctx.matrix = &audioMatrix;
    ctx.macros = &audioMacros;
    for (int i = 0; i < kNumMacros; ++i)
        ctx.macroValues[i] = v (paramIds::macros[i]);

    readOscParams (paramIds::oscillators[0], ctx.oscA);
    readOscParams (paramIds::oscillators[1], ctx.oscB);

    ctx.subOn     = v (ids::subOn) > 0.5f;
    ctx.subShape  = vic (ids::subShape, (int) SubShape::Count - 1);
    ctx.subOct    = vic (ids::subOct, 2) - 2;
    ctx.subLevel  = v (ids::subLevel);
    ctx.noiseOn    = v (ids::noiseOn) > 0.5f;
    ctx.noiseType  = vic (ids::noiseType, (int) NoiseType::Count - 1);
    ctx.noiseLevel = v (ids::noiseLevel);

    ctx.filters.f1On     = v (ids::f1On) > 0.5f;
    ctx.filters.f1Type   = vic (ids::f1Type, (int) FilterModel::Count - 1);
    ctx.filters.f1Cutoff = v (ids::f1Cutoff);
    ctx.filters.f1Res    = v (ids::f1Res);
    ctx.filters.f1Drive  = v (ids::f1Drive);
    ctx.filters.f1Key    = v (ids::f1Key);
    ctx.filters.f1Slope  = vic (ids::f1Slope, 2);
    ctx.filters.f2On     = v (ids::f2On) > 0.5f;
    ctx.filters.f2Type   = vic (ids::f2Type, (int) FilterModel::Count - 1);
    ctx.filters.f2Cutoff = v (ids::f2Cutoff);
    ctx.filters.f2Res    = v (ids::f2Res);
    ctx.filters.f2Drive  = v (ids::f2Drive);
    ctx.filters.f2Key    = v (ids::f2Key);
    ctx.filters.f2Slope  = vic (ids::f2Slope, 2);
    ctx.filters.route = vic (ids::fRoute, (int) FilterRoute::Count - 1);
    ctx.filters.mix   = v (ids::fMix);
    ctx.filters.out   = v (ids::fOut) * 1.5f;

    for (int i = 0; i < kNumEnvelopes; ++i)
    {
        ctx.envAttack[i]  = v (paramIds::envAttack[i]);
        ctx.envDecay[i]   = v (paramIds::envDecay[i]);
        ctx.envSustain[i] = v (paramIds::envSustain[i]);
        ctx.envRelease[i] = v (paramIds::envRelease[i]);
        ctx.envCurve[i]   = v (paramIds::envCurve[i]);
    }

    // FX rack.
    std::array<FxSlotParams, kNumFxSlots> slots;
    for (int i = 0; i < kNumFxSlots; ++i)
    {
        auto& slot = slots[(size_t) i];
        slot.type = vic (paramIds::fxType[i], (int) FxType::Count - 1);
        slot.mix  = v (paramIds::fxMix[i]);
        slot.p[0] = v (paramIds::fxP1[i]);
        slot.p[1] = v (paramIds::fxP2[i]);
        slot.p[2] = v (paramIds::fxP3[i]);
        slot.p[3] = v (paramIds::fxP4[i]);
    }
    if (v (ids::rave) > 0.5f)
        RaveController::apply (ctx, slots.data(), kNumFxSlots);

    int offset = 0;
    auto renderUntil = [&] (int end)
    {
        while (offset < end)
        {
            const int count = juce::jmin (end - offset, juce::jmin (blockSize, 64));
            ctx.modWheel = modWheel;
            ctx.pitchBend = pitchBend;
            for (int i = 0; i < kNumLfos; ++i)
                ctx.lfoValues[i] = lfos[(size_t) i].getValue();

            const SynthVoice* newest = nullptr;
            for (const auto& voice : voices)
                if (voice.isActive() && (newest == nullptr || voice.getNoteId() > newest->getNoteId()))
                    newest = &voice;
            auto sourceValue = [&] (ModSource source)
            {
                const int index = (int) source;
                if (source >= ModSource::Lfo1 && source <= ModSource::Lfo4)
                    return ctx.lfoValues[index - (int) ModSource::Lfo1];
                if (source >= ModSource::Macro1 && source <= ModSource::Macro4)
                    return ctx.macroValues[index - (int) ModSource::Macro1];
                if (source == ModSource::ModWheel) return modWheel;
                if (source == ModSource::PitchBend) return pitchBend;
                return newest != nullptr ? newest->getModulationValue (source) : 0.0f;
            };

            std::array<float, kNumModTargets> globalMod {};
            for (const auto& connection : audioMatrix.connections)
                if (! isPerVoiceTarget (connection.target))
                {
                    float value = sourceValue (connection.source);
                    if (connection.bipolar && ! isBipolarSource (connection.source))
                        value = value * 2.0f - 1.0f;
                    globalMod[(size_t) connection.target] += value * connection.depth;
                }
            for (int i = 0; i < kNumMacros; ++i)
                for (const auto& assignment : audioMacros.assignments[(size_t) i])
                    if (! isPerVoiceTarget (assignment.target))
                        globalMod[(size_t) assignment.target] += ctx.macroValues[i] * assignment.depth;

            // Prepare the voice mix buffer.
            juce::AudioBuffer<float> block (mixBuffer.getArrayOfWritePointers(), 2, count);
            block.clear();

            // Render all active voices into the mix buffer.
            for (auto& voice : voices)
                if (voice.isActive())
                    voice.render (block.getWritePointer (0), block.getWritePointer (1), count, ctx);

            auto modulatedSlots = slots;
            for (int i = 0; i < kNumFxSlots; ++i)
                modulatedSlots[(size_t) i].mix = juce::jlimit (0.0f, 1.0f,
                    slots[(size_t) i].mix + globalMod[(size_t) ModTarget::Fx1Mix + (size_t) i]);
            fx.process (block, modulatedSlots.data(), kNumFxSlots);

            // Master + soft limiting.
            const float master = juce::jlimit (0.0f, 1.0f, v (ids::master) + globalMod[(size_t) ModTarget::Master]);
            for (int ch = 0; ch < numCh; ++ch)
            {
                float* dest = buffer.getWritePointer (ch, offset);
                const float* src = block.getReadPointer (ch < 2 ? ch : 0);
                for (int i = 0; i < count; ++i)
                    dest[i] = limit (src[i] * master);
            }
            for (auto& lfo : lfos)
                lfo.advance (count);
            offset += count;
        }
    };

    // MIDI.
    for (const auto meta : midi)
    {
        renderUntil (juce::jlimit (offset, n, meta.samplePosition));
        const auto message = meta.getMessage();
        if (message.isNoteOn())
            noteOn (message.getNoteNumber(), message.getFloatVelocity());
        else if (message.isNoteOff())
            noteOff (message.getNoteNumber());
        else if (message.isPitchWheel())
            pitchBend = (message.getPitchWheelValue() - 8192) / 8192.0f;
        else if (message.isAllSoundOff())
        {
            for (auto& voice : voices)
                voice.reset();
            fx.reset();
        }
        else if (message.isAllNotesOff())
            allNotesOff();
        else if (message.isController() && message.getControllerNumber() == 1)
            modWheel = message.getControllerValue() / 127.0f;
    }
    renderUntil (n);

    int active = 0;
    for (const auto& voice : voices)
        active += voice.isActive() ? 1 : 0;
    activeVoiceCount.store (active, std::memory_order_relaxed);
}

} // namespace serum