// Standalone tests for reasampler::instrument::bake::bake_render — no VST3, no REAPER, no
// framework. Same fast assert loop as the sibling pure tests.
//
// Covers: Gate termination WITH a sustain loop active (the render must end at the window,
// and the tail must be silent because the gate actually released — not merely because the
// buffer ran out); Trigger termination on its own play span; channel-count preservation
// with no stereo fold; byte-identical repeats; and the refusals (unplayable sample, empty
// window).

#include "../src/core/instrument/bake/bake_render.h"

#include "../src/core/instrument/engine/live_params.h"

#include <cmath>
#include <cstdio>

using namespace reasampler;
using namespace reasampler::instrument::bake;

static int g_fail = 0;
#define CHECK(cond) do { if(!(cond)) { \
    std::printf("FAIL line %d: %s\n", __LINE__, #cond); ++g_fail; } } while(0)

namespace {

constexpr int kRate = 48000;

// Distinct per-channel DC so a downmix or a channel duplication is visible in the output
// rather than hidden behind two identical channels.
SampleData makeSample(bool stereo, std::size_t frames = 1000) {
    SampleData s;
    s.frames.assign(frames, 0.5f);
    if (stereo) s.framesR.assign(frames, -0.25f);
    s.sampleRate = kRate;
    s.rootNote = 60;
    return s;
}

// Peak magnitude of channel 0 over [from, to) output frames.
double peakAt(const BakeAudio& audio, std::int64_t from, std::int64_t to) {
    double peak = 0.0;
    for (std::int64_t f = from; f < to && f < audio.frameCount(); ++f) {
        const double v = std::fabs(
            static_cast<double>(audio.interleaved[static_cast<std::size_t>(
                f * audio.channelCount)]));
        if (v > peak) peak = v;
    }
    return peak;
}

BakePlan planOf(std::int64_t total, std::int64_t noteOn, std::int64_t noteOff) {
    BakePlan p;
    p.totalFrames = total;
    p.noteOnFrame = noteOn;
    p.noteOffFrame = noteOff;
    p.note = 60;
    p.velocity = 100;
    p.sampleRate = kRate;
    return p;
}

}  // namespace

int main() {
    // --- Gate, sustain loop active: the render terminates and the gate really released --
    {
        SampleData s = makeSample(/*stereo=*/false, /*frames=*/200);
        // A 100-frame loop over a 200-frame sample: held past the sample end it would cycle
        // forever, which is exactly the runaway the window has to bound.
        s.loop = SampleLoop{true, 0, 100};
        s.play.playMode = PlayMode::Gate;
        s.play.adsr.releaseFrames = 480;  // 10 ms — short enough to finish inside the tail

        const BakePlan plan = planOf(/*total=*/9600, /*noteOn=*/0, /*noteOff=*/4800);
        const BakeAudio audio = renderBake(s, plan);

        CHECK(audio.frameCount() == 9600);          // bounded, not a runaway
        CHECK(audio.channelCount == 1);
        // Sounding right up to the release…
        CHECK(peakAt(audio, 4700, 4800) > 0.4);
        // …and silent well after it, which only holds if the note-off was honoured: the
        // loop would otherwise still be cycling at full level here.
        CHECK(peakAt(audio, 6000, 9600) < 1e-6);
    }

    // --- Trigger: note-off is ignored, the play span ends the sound -------------------
    {
        SampleData s = makeSample(/*stereo=*/false, /*frames=*/1000);
        s.play.playMode = PlayMode::Trigger;
        s.play.trigger.lengthFraction = 0.5;  // 500 source frames at unity ratio

        const BakePlan plan = planOf(/*total=*/2000, /*noteOn=*/0, /*noteOff=*/100);
        const BakeAudio audio = renderBake(s, plan);

        CHECK(audio.frameCount() == 2000);
        // Still sounding past the note-off Trigger ignores…
        CHECK(peakAt(audio, 200, 400) > 0.4);
        // …and finished at its own span end, well before the window closes.
        CHECK(peakAt(audio, 700, 2000) < 1e-6);
    }

    // --- Channel count preserved; no stereo fold --------------------------------------
    {
        SampleData s = makeSample(/*stereo=*/true, /*frames=*/1000);
        s.play.playMode = PlayMode::Trigger;

        const BakePlan plan = planOf(/*total=*/500, /*noteOn=*/0, /*noteOff=*/500);
        const BakeAudio audio = renderBake(s, plan);

        CHECK(audio.channelCount == 2);
        CHECK(audio.frameCount() == 500);
        CHECK(audio.interleaved.size() == 1000u);
        // The two channels carry the source's two distinct signals: a downmix would make
        // them equal, a duplication would make R equal L.
        CHECK(audio.interleaved[200] > 0.4f);
        CHECK(audio.interleaved[201] < -0.2f);
        CHECK(audio.interleaved[201] > -0.3f);
    }

    // --- Bit-identical repeats ---------------------------------------------------------
    {
        SampleData s = makeSample(/*stereo=*/true, /*frames=*/1000);
        s.loop = SampleLoop{true, 0, 333};
        s.play.adsr.attackFrames = 97;   // a shape whose per-frame state must replay exactly
        s.play.adsr.releaseFrames = 211;

        const BakePlan plan = planOf(/*total=*/4096, /*noteOn=*/13, /*noteOff=*/2731);
        const BakeAudio a = renderBake(s, plan);
        const BakeAudio b = renderBake(s, plan);

        CHECK(a.interleaved.size() == b.interleaved.size());
        CHECK(!a.interleaved.empty());
        bool identical = a.interleaved.size() == b.interleaved.size();
        for (std::size_t i = 0; identical && i < a.interleaved.size(); ++i)
            identical = (a.interleaved[i] == b.interleaved[i]);
        CHECK(identical);
        // The window opened before the note: those frames must be untouched silence.
        CHECK(peakAt(a, 0, 13) == 0.0);
        CHECK(peakAt(a, 200, 400) > 0.0);
    }

    // --- The bake is off the audio thread's block, structurally ------------------------
    // The only thing process() and a bake could share is the live-parameter block. This
    // pins that they do not: the caller's SampleData is untouched (renderBake took a
    // copy), and the render ignores what is published in the block — the bake prints the
    // dialed parameter set, not whatever the audio thread is currently observing.
    {
        instrument::engine::LiveParams block;
        SampleData s = makeSample(/*stereo=*/false, /*frames=*/1000);
        s.play.playMode = PlayMode::Trigger;
        s.play.trigAhd.attackFrames = 0;  // dialed: instant attack

        // Publish a MUCH slower attack into the block. A render that observed it would be
        // near-silent at the point the dialed shape is already at full level.
        s.live = &block;
        {
            PlayParams slow = s.play;
            slow.trigAhd.attackFrames = 900;
            block.publish(instrument::engine::foldLive(slow));
        }

        const BakePlan plan = planOf(/*total=*/1000, /*noteOn=*/0, /*noteOff=*/1000);
        const BakeAudio audio = renderBake(s, plan);

        CHECK(s.live == &block);  // the caller's own snapshot was not detached
        // At frame 100 the dialed instant attack is at full level; the published 900-frame
        // attack would be barely a ninth of the way up.
        CHECK(peakAt(audio, 90, 110) > 0.4);

        // And it matches a render from a block-free copy exactly.
        SampleData detached = s;
        detached.live = nullptr;
        const BakeAudio reference = renderBake(detached, plan);
        bool identical = audio.interleaved.size() == reference.interleaved.size();
        for (std::size_t i = 0; identical && i < audio.interleaved.size(); ++i)
            identical = (audio.interleaved[i] == reference.interleaved[i]);
        CHECK(identical);
    }

    // --- Refusals -----------------------------------------------------------------------
    {
        SampleData empty;  // nothing decoded
        empty.sampleRate = kRate;
        CHECK(renderBake(empty, planOf(1000, 0, 500)).empty());

        SampleData s = makeSample(false);
        CHECK(renderBake(s, planOf(0, 0, 0)).empty());
    }

    if (g_fail == 0) std::printf("bake_render: all tests passed\n");
    return g_fail ? 1 : 0;
}