// component_state_io unit tests — the codec's whole suite: the current envelope + params
// payload round-trip, the frozen prefix bytes, the ENVELOPE ladder (v1..v11) with each
// version's documented lift, and the RETIRED-ZONE-PAYLOAD migration ladder (payload v1..v7
// -> the one parameter set, adopting zone one). The codec's own executable is also the
// STRUCTURAL PROOF it links WITHOUT the voice engine: it links component_state_io +
// velocity_curve + master_gain only, so a sampler_core/pitch_shift symbol reaching this
// link is a regression.

#include "../src/core/instrument/map/component_state_io.h"
#include "../src/core/instrument/engine/master_gain.h"  // masterGainMaxLinear (the v8 wire cap)

#include <cstdio>
#include <cstring>
#include <string>
#include <vector>

using namespace reasampler;
using namespace reasampler::instrument::map;

static int failures = 0;

#define CHECK(cond)                                                    \
    do {                                                               \
        if (!(cond)) {                                                 \
            std::printf("FAIL %s:%d: %s\n", __FILE__, __LINE__, #cond); \
            ++failures;                                                \
        }                                                              \
    } while (0)

// --- A writer for the RETIRED zone-list payloads -----------------------------
//
// The shipping codec no longer EMITS a zone list, so the migration ladder can only be
// tested against bytes this suite lays out itself. These helpers mirror the frozen v1..v7
// record shapes documented in component_state_io.h; if they and the reader ever disagree,
// the migration tests below fail — which is the point.

namespace legacy {

static void u8v(std::vector<std::uint8_t>& out, std::uint8_t v) { out.push_back(v); }

static void u32v(std::vector<std::uint8_t>& out, std::uint32_t v) {
    for (int i = 0; i < 4; ++i) out.push_back(static_cast<std::uint8_t>((v >> (8 * i)) & 0xFF));
}

static void i64v(std::vector<std::uint8_t>& out, std::int64_t v) {
    const auto u = static_cast<std::uint64_t>(v);
    for (int i = 0; i < 8; ++i) out.push_back(static_cast<std::uint8_t>((u >> (8 * i)) & 0xFF));
}

static void f64v(std::vector<std::uint8_t>& out, double v) {
    std::uint64_t bits = 0;
    std::memcpy(&bits, &v, sizeof(bits));
    for (int i = 0; i < 8; ++i) out.push_back(static_cast<std::uint8_t>((bits >> (8 * i)) & 0xFF));
}

static void strv(std::vector<std::uint8_t>& out, const std::string& s) {
    u32v(out, static_cast<std::uint32_t>(s.size()));
    out.insert(out.end(), s.begin(), s.end());
}

// One zone's worth of the retired per-zone record, in the v7 (fullest) shape.
struct Zone {
    std::string sampleId;
    int lowNote = 0;
    int highNote = 127;
    int rootOverride = -1;          // < 0 = absent
    bool hasLoopOverride = false;
    // The override's OWN hasLoop bit — distinct from hasLoopOverride above. An override can
    // itself say "disable the loop" (loopOverrideHasLoop = false): the field is present but
    // sets no sustain loop, as opposed to no override at all (the sample's own intrinsic loop
    // applies). Defaults true so existing callers that only set hasLoopOverride keep writing
    // the enabled-loop shape they always did.
    bool loopOverrideHasLoop = true;
    std::int64_t loopStart = 0;
    std::int64_t loopEnd = 0;
    std::int64_t startPoint = -1;   // < 0 = absent
    bool trigger = false;
    double holdSeconds = 0.0;
    double lengthFraction = 1.0;
    std::int64_t fadeIn = 0;
    std::int64_t fadeOut = 0;
    bool preserve = false;
    bool pitchEnvEnabled = false;
    double pitchAttack = 0.0;
    double pitchDecay = 0.0;
    double peakSemis = 0.0;
    double attackSeconds = 0.003;
    double decaySeconds = 0.0;
    double sustainLevel = 1.0;
    double releaseSeconds = 0.060;
    double keyTrack = 1.0;
    std::vector<VelocityPoint> curve;  // empty -> the flat endpoints
};

static void putZone(std::vector<std::uint8_t>& out, const Zone& z, std::uint32_t pv) {
    strv(out, z.sampleId);
    u32v(out, static_cast<std::uint32_t>(z.lowNote));
    u32v(out, static_cast<std::uint32_t>(z.highNote));
    u8v(out, z.rootOverride >= 0 ? 1 : 0);
    if (z.rootOverride >= 0) u32v(out, static_cast<std::uint32_t>(z.rootOverride));
    if (pv >= 2) {
        u8v(out, z.hasLoopOverride ? 1 : 0);
        if (z.hasLoopOverride) {
            u8v(out, z.loopOverrideHasLoop ? 1 : 0);
            i64v(out, z.loopStart);
            i64v(out, z.loopEnd);
        }
        u8v(out, z.startPoint >= 0 ? 1 : 0);
        if (z.startPoint >= 0) i64v(out, z.startPoint);
    }
    if (pv >= 5) {
        u8v(out, z.trigger ? 1 : 0);
        f64v(out, z.holdSeconds);
        f64v(out, z.lengthFraction);
        i64v(out, z.fadeIn);
        i64v(out, z.fadeOut);
        u8v(out, z.preserve ? 1 : 0);
        u8v(out, z.pitchEnvEnabled ? 1 : 0);
        f64v(out, z.pitchAttack);
        f64v(out, z.pitchDecay);
        f64v(out, z.peakSemis);
        f64v(out, z.attackSeconds);
        f64v(out, z.decaySeconds);
        f64v(out, z.sustainLevel);
        f64v(out, z.releaseSeconds);
    }
    if (pv >= 6) f64v(out, z.keyTrack);
    if (pv >= 7) {
        const std::vector<VelocityPoint> pts =
            z.curve.empty() ? std::vector<VelocityPoint>{{0.0, 1.0}, {127.0, 1.0}} : z.curve;
        u32v(out, static_cast<std::uint32_t>(pts.size()));
        for (const VelocityPoint& p : pts) { f64v(out, p.velocity); f64v(out, p.amp); }
    }
}

// The envelope fields, in wire order. A builder at version N emits only the prefix fields
// version N carried, so each lift can be asserted against a blob shaped exactly as that
// version's writer produced.
struct Envelope {
    std::uint32_t version = kComponentStateVersion;
    std::uint8_t modeByte = 0;                  // v4+   0 mono / 1 stereo
    std::int64_t assignGeneration = 0;          // v5+
    std::uint8_t previewVelocity = kPreviewVelocityDefault;  // v6+
    std::uint8_t voiceCount = static_cast<std::uint8_t>(kDefaultVoiceCount);  // v7+
    std::uint8_t voiceMode = 0;                 // v7+   0 poly / 1 mono
    std::uint8_t monoTrigger = 0;               // v7+   0 retrigger / 1 legato
    double masterGain = 1.0;                    // v8+
    std::uint8_t channelModeExplicit = 0;       // v9+
    std::string instanceGuid;                   // v11+
    std::string selectionId;                    // v3+
};

// A complete envelope at `env.version` whose tail is a RETIRED zone-list payload at version
// `pv`. `env.selectionId` is the envelope's own stored pick — which the adoption rule
// overrides when the payload carries a zone. The sample-refs table (v10+) is always empty:
// its own shape is covered by the round-trip test.
static std::vector<std::uint8_t> envelopeWithZones(const Envelope& env,
                                                   const std::vector<Zone>& zones,
                                                   std::uint32_t pv) {
    std::vector<std::uint8_t> out;
    const std::uint32_t v = env.version;
    u32v(out, v);
    if (v >= 4) u8v(out, env.modeByte);
    if (v >= 5) i64v(out, env.assignGeneration);
    if (v >= 6) u8v(out, env.previewVelocity);
    if (v >= 7) { u8v(out, env.voiceCount); u8v(out, env.voiceMode); u8v(out, env.monoTrigger); }
    if (v >= 8) f64v(out, env.masterGain);
    if (v >= 9) u8v(out, env.channelModeExplicit);
    if (v >= 10) u32v(out, 0);                  // sample-refs: empty table
    if (v >= 11) strv(out, env.instanceGuid);
    if (v >= 3) strv(out, env.selectionId);     // v2 was zones-only, no selection
    if (pv >= 2) {
        u32v(out, kParamsFormatMarker);
        u32v(out, pv);
    }
    u32v(out, static_cast<std::uint32_t>(zones.size()));
    for (const Zone& z : zones) putZone(out, z, pv);
    return out;
}

// Shorthand for the common case: the CURRENT envelope version carrying a zone payload.
static std::vector<std::uint8_t> envelopeWithZones(const std::string& selectionId,
                                                   const std::vector<Zone>& zones,
                                                   std::uint32_t pv) {
    Envelope env;
    env.selectionId = selectionId;
    return envelopeWithZones(env, zones, pv);
}

}  // namespace legacy

// --- The current format -------------------------------------------------------

// Builds a SampleRefEntry with the intrinsics fields the refs-robustness tests below need to
// set individually (root/loop/channels), mirroring the codec's own field names.
static SampleRefEntry refEntry(const std::string& id, const std::string& rel, int root,
                               bool hasLoop = false, std::int64_t loopStart = 0,
                               std::int64_t loopEnd = 0, int channels = 0,
                               const std::string& name = "") {
    SampleRefEntry e;
    e.sampleId = id;
    e.ref.relativePath = rel;
    e.ref.rootNote = root;
    e.ref.loop.hasLoop = hasLoop;
    e.ref.loop.start = loopStart;
    e.ref.loop.end = loopEnd;
    e.ref.channelCount = channels;
    e.displayName = name;
    return e;
}

// A full round-trip through the CURRENT envelope (v11) + params payload (v8): every field
// survives. This is the "one parameter set round-trips save/reload intact" contract.
static void testComponentStateRoundTrip() {
    ComponentState in;
    in.selectionId = "smp-1";
    in.channelMode = ChannelMode::Stereo;
    in.channelModeExplicit = true;
    in.lastConsumedAssignGeneration = 42;
    in.previewVelocity = 99;
    in.voiceCount = 7;
    in.voiceMode = VoiceMode::Mono;
    in.monoTrigger = MonoTrigger::Legato;
    in.masterGainLinear = 0.5;
    in.instanceGuid = "0123456789abcdef0123456789abcdef";
    SampleRefEntry e;
    e.sampleId = "smp-1";
    e.ref.relativePath = "bank/smp-1.wav";
    e.ref.rootNote = 64;
    e.ref.loop.hasLoop = true;
    e.ref.loop.start = 100;
    e.ref.loop.end = 2000;
    e.ref.channelCount = 2;
    e.displayName = "My Capture";
    in.sampleRefs.push_back(e);
    in.params.rootOverride = 61;
    SampleLoop lp;
    lp.hasLoop = true;
    lp.start = 7;
    lp.end = 900;
    in.params.loopOverride = lp;
    in.params.startPoint = 5;
    in.params.keyTrack = 1.5;
    in.params.velocityCurve = reasampler::instrument::engine::VelocityCurve::fromPoints(
        {VelocityPoint{0.0, 0.2}, VelocityPoint{64.0, 0.6}, VelocityPoint{127.0, 1.0}});
    in.params.play.playMode = PlayMode::Trigger;
    in.params.play.adsr.attackSeconds = 0.01;
    in.params.play.adsr.holdSeconds = 0.05;
    in.params.play.adsr.decaySeconds = 0.02;
    in.params.play.adsr.sustainLevel = 0.8;
    in.params.play.adsr.releaseSeconds = 0.15;
    in.params.play.trigger.lengthFraction = 0.75;
    in.params.play.trigger.fadeInFrames = 441;
    in.params.play.trigger.fadeOutFrames = 882;
    in.params.play.pitchEngine = PitchEngine::Preserve;
    in.params.play.pitchEnv.enabled = true;
    in.params.play.pitchEnv.attackSeconds = 0.02;
    in.params.play.pitchEnv.decaySeconds = 0.03;
    in.params.play.pitchEnv.peakSemitones = 5.0;

    const std::vector<std::uint8_t> bytes = serializeComponentState(in);
    const ComponentState out = deserializeComponentState(bytes, 48000.0);

    CHECK(out.selectionId == "smp-1");
    CHECK(out.channelMode == ChannelMode::Stereo);
    CHECK(out.channelModeExplicit);
    CHECK(out.lastConsumedAssignGeneration == 42);
    CHECK(out.previewVelocity == 99);
    CHECK(out.voiceCount == 7);
    CHECK(out.voiceMode == VoiceMode::Mono);
    CHECK(out.monoTrigger == MonoTrigger::Legato);
    CHECK(out.masterGainLinear == 0.5);
    CHECK(out.instanceGuid == "0123456789abcdef0123456789abcdef");
    CHECK(out.sampleRefs.size() == 1);
    if (out.sampleRefs.size() == 1) {
        CHECK(out.sampleRefs[0].sampleId == "smp-1");
        CHECK(out.sampleRefs[0].ref.relativePath == "bank/smp-1.wav");
        CHECK(out.sampleRefs[0].ref.rootNote == 64);
        CHECK(out.sampleRefs[0].ref.loop.hasLoop);
        CHECK(out.sampleRefs[0].ref.loop.start == 100);
        CHECK(out.sampleRefs[0].ref.loop.end == 2000);
        CHECK(out.sampleRefs[0].ref.channelCount == 2);
        CHECK(out.sampleRefs[0].displayName == "My Capture");
    }
    const InstrumentParams& p = out.params;
    CHECK(p.rootOverride && *p.rootOverride == 61);
    CHECK(p.loopOverride && p.loopOverride->hasLoop);
    CHECK(p.loopOverride && p.loopOverride->start == 7 && p.loopOverride->end == 900);
    CHECK(p.startPoint && *p.startPoint == 5);
    CHECK(p.keyTrack == 1.5);
    CHECK(p.velocityCurve.points().size() == 3);
    CHECK(p.play.playMode == PlayMode::Trigger);
    CHECK(p.play.adsr.attackSeconds == 0.01);
    CHECK(p.play.adsr.holdSeconds == 0.05);
    CHECK(p.play.adsr.decaySeconds == 0.02);
    CHECK(p.play.adsr.sustainLevel == 0.8);
    CHECK(p.play.adsr.releaseSeconds == 0.15);
    CHECK(p.play.trigger.lengthFraction == 0.75);
    CHECK(p.play.trigger.fadeInFrames == 441);
    CHECK(p.play.trigger.fadeOutFrames == 882);
    CHECK(p.play.pitchEngine == PitchEngine::Preserve);
    CHECK(p.play.pitchEnv.enabled);
    CHECK(p.play.pitchEnv.attackSeconds == 0.02);
    CHECK(p.play.pitchEnv.decaySeconds == 0.03);
    CHECK(p.play.pitchEnv.peakSemitones == 5.0);
}

// GOLDEN FULL-BLOB FIXTURE (reviewer follow-up). testEnvelopePrefixBytesFrozen below only
// pins the first 5 bytes of a near-EMPTY blob; it cannot catch a drift anywhere past the mode
// byte (a field re-ordered or dropped inside the voice/gain/refs/guid/params tail would still
// pass it). This builds a canonical v11 ComponentState/v8-params blob that exercises every
// field family at once (a two-entry sample-refs table — one with a loop, one without — every
// optional param field present, a non-flat velocity curve, Trigger mode with a pitch envelope)
// and asserts the encoded bytes equal an EXACT expected vector, captured from the current
// writer's output and checked field-for-field against the v8/v11 layout documented in
// component_state_io.h.
static void testGoldenFullBlobFixture() {
    ComponentState in;
    in.selectionId = "kick";
    in.channelMode = ChannelMode::Stereo;
    in.channelModeExplicit = true;
    in.lastConsumedAssignGeneration = 12345;
    in.previewVelocity = 100;
    in.voiceCount = 24;
    in.voiceMode = VoiceMode::Mono;
    in.monoTrigger = MonoTrigger::Legato;
    in.masterGainLinear = 2.0;
    in.instanceGuid = "guid-1234-5678-abcd";

    SampleRefEntry kickRef;
    kickRef.sampleId = "kick";
    kickRef.ref.relativePath = "bank/kick.wav";
    kickRef.ref.rootNote = 36;
    kickRef.ref.loop.hasLoop = true;
    kickRef.ref.loop.start = 1000;
    kickRef.ref.loop.end = 5000;
    kickRef.ref.channelCount = 2;
    kickRef.displayName = "Kick Drum";
    in.sampleRefs.push_back(kickRef);

    SampleRefEntry snareRef;
    snareRef.sampleId = "snare";
    snareRef.ref.relativePath = "bank/snare.wav";
    snareRef.ref.rootNote = 38;
    snareRef.ref.loop.hasLoop = false;
    snareRef.ref.loop.start = 0;
    snareRef.ref.loop.end = 0;
    snareRef.ref.channelCount = 1;
    snareRef.displayName = "Snare";
    in.sampleRefs.push_back(snareRef);

    in.params.rootOverride = 36;
    SampleLoop loopA;
    loopA.hasLoop = true;
    loopA.start = 1000;
    loopA.end = 5000;
    in.params.loopOverride = loopA;
    in.params.startPoint = 250;
    in.params.keyTrack = 0.5;
    in.params.velocityCurve = reasampler::instrument::engine::VelocityCurve::fromPoints(
        {VelocityPoint{0.0, 0.2}, VelocityPoint{64.0, 0.6}, VelocityPoint{127.0, 1.0}});
    in.params.play.playMode = PlayMode::Trigger;
    in.params.play.adsr.attackSeconds = 0.01;
    in.params.play.adsr.holdSeconds = 0.05;
    in.params.play.adsr.decaySeconds = 0.02;
    in.params.play.adsr.sustainLevel = 0.8;
    in.params.play.adsr.releaseSeconds = 0.15;
    in.params.play.trigger.lengthFraction = 0.75;
    in.params.play.trigger.fadeInFrames = 100;
    in.params.play.trigger.fadeOutFrames = 200;
    in.params.play.pitchEngine = PitchEngine::Preserve;
    in.params.play.pitchEnv.enabled = true;
    in.params.play.pitchEnv.attackSeconds = 0.02;
    in.params.play.pitchEnv.decaySeconds = 0.03;
    in.params.play.pitchEnv.peakSemitones = 5.0;

    const std::vector<std::uint8_t> bytes = serializeComponentState(in);
    // clang-format off
    static const std::uint8_t kGolden[] = {
        0x0b,0x00,0x00,0x00,0x01,0x39,0x30,0x00,0x00,0x00,0x00,0x00,0x00,0x64,0x18,0x01,
        0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x40,0x01,0x02,0x00,0x00,0x00,0x04,0x00,
        0x00,0x00,0x6b,0x69,0x63,0x6b,0x0d,0x00,0x00,0x00,0x62,0x61,0x6e,0x6b,0x2f,0x6b,
        0x69,0x63,0x6b,0x2e,0x77,0x61,0x76,0x24,0x00,0x00,0x00,0x01,0xe8,0x03,0x00,0x00,
        0x00,0x00,0x00,0x00,0x88,0x13,0x00,0x00,0x00,0x00,0x00,0x00,0x02,0x00,0x00,0x00,
        0x09,0x00,0x00,0x00,0x4b,0x69,0x63,0x6b,0x20,0x44,0x72,0x75,0x6d,0x05,0x00,0x00,
        0x00,0x73,0x6e,0x61,0x72,0x65,0x0e,0x00,0x00,0x00,0x62,0x61,0x6e,0x6b,0x2f,0x73,
        0x6e,0x61,0x72,0x65,0x2e,0x77,0x61,0x76,0x26,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x00,0x00,
        0x00,0x05,0x00,0x00,0x00,0x53,0x6e,0x61,0x72,0x65,0x13,0x00,0x00,0x00,0x67,0x75,
        0x69,0x64,0x2d,0x31,0x32,0x33,0x34,0x2d,0x35,0x36,0x37,0x38,0x2d,0x61,0x62,0x63,
        0x64,0x04,0x00,0x00,0x00,0x6b,0x69,0x63,0x6b,0x00,0xff,0xff,0xff,0x08,0x00,0x00,
        0x00,0x01,0x24,0x00,0x00,0x00,0x01,0x01,0xe8,0x03,0x00,0x00,0x00,0x00,0x00,0x00,
        0x88,0x13,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0xfa,0x00,0x00,0x00,0x00,0x00,0x00,
        0x00,0x01,0x9a,0x99,0x99,0x99,0x99,0x99,0xa9,0x3f,0x00,0x00,0x00,0x00,0x00,0x00,
        0xe8,0x3f,0x64,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xc8,0x00,0x00,0x00,0x00,0x00,
        0x00,0x00,0x01,0x01,0x7b,0x14,0xae,0x47,0xe1,0x7a,0x94,0x3f,0xb8,0x1e,0x85,0xeb,
        0x51,0xb8,0x9e,0x3f,0x00,0x00,0x00,0x00,0x00,0x00,0x14,0x40,0x7b,0x14,0xae,0x47,
        0xe1,0x7a,0x84,0x3f,0x7b,0x14,0xae,0x47,0xe1,0x7a,0x94,0x3f,0x9a,0x99,0x99,0x99,
        0x99,0x99,0xe9,0x3f,0x33,0x33,0x33,0x33,0x33,0x33,0xc3,0x3f,0x00,0x00,0x00,0x00,
        0x00,0x00,0xe0,0x3f,0x03,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
        0x9a,0x99,0x99,0x99,0x99,0x99,0xc9,0x3f,0x00,0x00,0x00,0x00,0x00,0x00,0x50,0x40,
        0x33,0x33,0x33,0x33,0x33,0x33,0xe3,0x3f,0x00,0x00,0x00,0x00,0x00,0xc0,0x5f,0x40,
        0x00,0x00,0x00,0x00,0x00,0x00,0xf0,0x3f,
    };
    // clang-format on
    CHECK(bytes.size() == sizeof(kGolden));
    if (bytes.size() == sizeof(kGolden)) {
        bool same = true;
        for (std::size_t i = 0; i < bytes.size(); ++i) {
            if (bytes[i] != kGolden[i]) { same = false; break; }
        }
        CHECK(same);
    }
}

// A DEFAULT parameter set must round-trip to defaults — the "no pick, nothing configured"
// blob restores as the silent empty state, not as a set of accidental values.
static void testDefaultStateRoundTripsToDefaults() {
    const ComponentState out =
        deserializeComponentState(serializeComponentState(ComponentState{}), 48000.0);
    CHECK(out.selectionId.empty());
    CHECK(!out.params.rootOverride);
    CHECK(!out.params.loopOverride);
    CHECK(!out.params.startPoint);
    CHECK(out.params.keyTrack == 1.0);
    CHECK(out.params.play.playMode == PlayMode::Gate);
    CHECK(out.params.play.pitchEngine == kDefaultPitchEngine);
    CHECK(!out.params.play.pitchEnv.enabled);
    CHECK(out.params.play.adsr.attackSeconds == AdsrSeconds{}.attackSeconds);
    CHECK(out.params.play.adsr.releaseSeconds == AdsrSeconds{}.releaseSeconds);
}

// The FROZEN envelope prefix: version tag v11 LE, then the mode byte — a drift in either is
// a byte-format break the round-trip alone can't prove (both sides could drift together).
// Also pins the payload version + marker as SEMANTIC constants, so a bump has to be
// deliberate rather than incidental.
static void testEnvelopePrefixBytesFrozen() {
    ComponentState in;  // defaults: mono, implicit, no refs, no selection, default params
    const std::vector<std::uint8_t> bytes = serializeComponentState(in);
    CHECK(bytes.size() > 5);
    if (bytes.size() > 5) {
        CHECK(bytes[0] == 11 && bytes[1] == 0 && bytes[2] == 0 && bytes[3] == 0);
        CHECK(bytes[4] == 0);  // ChannelMode::Mono
    }
    CHECK(kComponentStateVersion == 11);
    CHECK(kParamsPayloadVersion == 8);
    CHECK(kParamsFormatMarker == 0xFFFFFF00u);
}

// The WRITER emits the CURRENT payload version, and the marker + version sit at the head of
// the payload — the self-describing property every legacy branch depends on. Asserted
// against the semantic constants, not literals.
static void testWriterEmitsCurrentPayloadVersion() {
    ComponentState in;
    in.selectionId = "id";
    const std::vector<std::uint8_t> bytes = serializeComponentState(in);
    // Scan for the marker; the four bytes after it are the payload version.
    bool found = false;
    for (std::size_t i = 0; i + 8 <= bytes.size(); ++i) {
        const std::uint32_t m = static_cast<std::uint32_t>(bytes[i]) |
                                (static_cast<std::uint32_t>(bytes[i + 1]) << 8) |
                                (static_cast<std::uint32_t>(bytes[i + 2]) << 16) |
                                (static_cast<std::uint32_t>(bytes[i + 3]) << 24);
        if (m != kParamsFormatMarker) continue;
        const std::uint32_t v = static_cast<std::uint32_t>(bytes[i + 4]) |
                                (static_cast<std::uint32_t>(bytes[i + 5]) << 8) |
                                (static_cast<std::uint32_t>(bytes[i + 6]) << 16) |
                                (static_cast<std::uint32_t>(bytes[i + 7]) << 24);
        CHECK(v == kParamsPayloadVersion);
        found = true;
        break;
    }
    CHECK(found);
}

// --- The retired-zone-payload migration ladder --------------------------------

// SINGLE-ZONE LIFT IS LOSSLESS: a single-capture instance saved under the zone model
// restores with the same capture, the same root, and the same parameters.
static void testSingleZoneMigrationIsLossless() {
    legacy::Zone z;
    z.sampleId = "kick";
    z.lowNote = 0;
    z.highNote = 127;
    z.rootOverride = 36;
    z.hasLoopOverride = true;
    z.loopStart = 1000;
    z.loopEnd = 5000;
    z.startPoint = 250;
    z.trigger = true;
    z.holdSeconds = 0.05;
    z.lengthFraction = 0.75;
    z.fadeIn = 100;
    z.fadeOut = 200;
    z.preserve = true;
    z.pitchEnvEnabled = true;
    z.pitchAttack = 0.02;
    z.pitchDecay = 0.03;
    z.peakSemis = 5.0;
    z.attackSeconds = 0.01;
    z.decaySeconds = 0.02;
    z.sustainLevel = 0.8;
    z.releaseSeconds = 0.15;
    z.keyTrack = 0.5;
    z.curve = {VelocityPoint{0.0, 0.2}, VelocityPoint{64.0, 0.6}, VelocityPoint{127.0, 1.0}};

    const ComponentState out =
        deserializeComponentState(legacy::envelopeWithZones("kick", {z}, 7), 48000.0);

    CHECK(out.selectionId == "kick");                 // same capture
    const InstrumentParams& p = out.params;
    CHECK(p.rootOverride && *p.rootOverride == 36);   // same root
    CHECK(p.loopOverride && p.loopOverride->start == 1000 && p.loopOverride->end == 5000);
    CHECK(p.startPoint && *p.startPoint == 250);
    CHECK(p.keyTrack == 0.5);
    CHECK(p.velocityCurve.points().size() == 3);
    CHECK(p.play.playMode == PlayMode::Trigger);
    CHECK(p.play.adsr.attackSeconds == 0.01);
    CHECK(p.play.adsr.holdSeconds == 0.05);
    CHECK(p.play.adsr.decaySeconds == 0.02);
    CHECK(p.play.adsr.sustainLevel == 0.8);
    CHECK(p.play.adsr.releaseSeconds == 0.15);
    CHECK(p.play.trigger.lengthFraction == 0.75);
    CHECK(p.play.trigger.fadeInFrames == 100);
    CHECK(p.play.trigger.fadeOutFrames == 200);
    CHECK(p.play.pitchEngine == PitchEngine::Preserve);
    CHECK(p.play.pitchEnv.enabled);
    CHECK(p.play.pitchEnv.attackSeconds == 0.02);
    CHECK(p.play.pitchEnv.decaySeconds == 0.03);
    CHECK(p.play.pitchEnv.peakSemitones == 5.0);
}

// A legacy OVERRIDE THAT DISABLES THE LOOP migrates as a PRESENT loopOverride with hasLoop
// false — distinct from no override at all (which leaves the sample's own intrinsic loop in
// force). The writer always emitted the override's inner hasLoop bit as true; this is the
// disabled shape it never exercised.
static void testSingleZoneMigrationLiftsLoopDisablingOverride() {
    legacy::Zone z;
    z.sampleId = "kick";
    z.hasLoopOverride = true;
    z.loopOverrideHasLoop = false;
    z.loopStart = 1000;
    z.loopEnd = 5000;

    const ComponentState out =
        deserializeComponentState(legacy::envelopeWithZones("kick", {z}, 7), 48000.0);

    const InstrumentParams& p = out.params;
    CHECK(p.loopOverride.has_value());
    CHECK(p.loopOverride && !p.loopOverride->hasLoop);
}

// A lifted single-zone instance RE-SAVES in the current format and survives a second
// round-trip unchanged — the lift is a one-way door, not a per-open re-derivation.
static void testLiftedStateReSavesInCurrentFormat() {
    legacy::Zone z;
    z.sampleId = "kick";
    z.rootOverride = 36;
    z.keyTrack = 0.5;
    z.releaseSeconds = 0.4;
    const ComponentState lifted =
        deserializeComponentState(legacy::envelopeWithZones("kick", {z}, 7), 48000.0);
    const ComponentState again =
        deserializeComponentState(serializeComponentState(lifted), 48000.0);
    CHECK(again.selectionId == "kick");
    CHECK(again.params.rootOverride && *again.params.rootOverride == 36);
    CHECK(again.params.keyTrack == 0.5);
    CHECK(again.params.play.adsr.releaseSeconds == 0.4);
}

// MULTI-ZONE LIFT ADOPTS ZONE ONE: its capture AND its parameters win; every later zone
// drops. No error, no empty state.
static void testMultiZoneMigrationAdoptsFirstZone() {
    legacy::Zone first;
    first.sampleId = "kick";
    first.lowNote = 0;
    first.highNote = 59;
    first.rootOverride = 36;
    first.keyTrack = 0.5;
    first.releaseSeconds = 0.4;

    legacy::Zone second;
    second.sampleId = "snare";
    second.lowNote = 60;
    second.highNote = 127;
    second.rootOverride = 38;
    second.keyTrack = 2.0;
    second.releaseSeconds = 0.9;

    legacy::Zone third;
    third.sampleId = "hat";
    third.rootOverride = 42;

    const ComponentState out = deserializeComponentState(
        legacy::envelopeWithZones("", {first, second, third}, 7), 48000.0);

    CHECK(out.selectionId == "kick");                 // zone one's capture
    CHECK(out.params.rootOverride && *out.params.rootOverride == 36);
    CHECK(out.params.keyTrack == 0.5);                // zone one's parameters
    CHECK(out.params.play.adsr.releaseSeconds == 0.4);
    // Zones two and three left no trace anywhere.
    CHECK(out.selectionId != "snare" && out.selectionId != "hat");
    CHECK(out.params.keyTrack != 2.0);
}

// The FIRST zone supersedes the envelope's own stored selection — that zone is what
// first-match resolve actually played, so adopting it is what keeps the sound identical.
static void testFirstZoneSupersedesStoredSelection() {
    legacy::Zone z;
    z.sampleId = "actually-playing";
    const ComponentState out = deserializeComponentState(
        legacy::envelopeWithZones("stale-selection", {z}, 7), 48000.0);
    CHECK(out.selectionId == "actually-playing");
}

// An EMPTY zone list leaves the envelope's selection alone (a picked-but-never-edited
// instance) and yields default parameters.
static void testEmptyZoneListKeepsTheStoredSelection() {
    const ComponentState out =
        deserializeComponentState(legacy::envelopeWithZones("picked", {}, 7), 48000.0);
    CHECK(out.selectionId == "picked");
    CHECK(!out.params.rootOverride);
    CHECK(out.params.keyTrack == 1.0);
}

// EVERY older payload version takes the migration path, and each lifts the fields its own
// shape carries while defaulting the ones it predates.
static void testEveryOlderPayloadVersionMigrates() {
    for (std::uint32_t pv : {1u, 2u, 5u, 6u, 7u}) {
        legacy::Zone z;
        z.sampleId = "kick";
        z.rootOverride = 36;
        z.keyTrack = 0.5;
        z.releaseSeconds = 0.4;
        const ComponentState out =
            deserializeComponentState(legacy::envelopeWithZones("", {z}, pv), 48000.0);
        CHECK(out.selectionId == "kick");                                 // every version
        CHECK(out.params.rootOverride && *out.params.rootOverride == 36); // v1 onward
        // keyTrack arrived at v6; older payloads lift to 100% ET (bit-identical repitch).
        CHECK(out.params.keyTrack == (pv >= 6 ? 0.5 : 1.0));
        // The full A/D/S/R tail arrived at v5; older payloads keep the tier-0 defaults.
        CHECK(out.params.play.adsr.releaseSeconds ==
              (pv >= 5 ? 0.4 : AdsrSeconds{}.releaseSeconds));
    }
    // And the CURRENT version does NOT take the migration path: it reads its own record.
    CHECK(kParamsPayloadVersion == 8);
}

// The LEGACY v3 payload's wall-clock frame counts convert to seconds at the READ boundary
// using the project rate threaded in — no baked constant.
static void testLegacyV3FramesConvertAtTheProjectRate() {
    // v3's own tail shape differs from v5's, so lay it out directly here.
    std::vector<std::uint8_t> out;
    legacy::u32v(out, kComponentStateVersion);
    legacy::u8v(out, 0);
    legacy::i64v(out, 0);
    legacy::u8v(out, kPreviewVelocityDefault);
    legacy::u8v(out, static_cast<std::uint8_t>(kDefaultVoiceCount));
    legacy::u8v(out, 0);
    legacy::u8v(out, 0);
    legacy::f64v(out, 1.0);
    legacy::u8v(out, 0);
    legacy::u32v(out, 0);
    legacy::strv(out, "");
    legacy::strv(out, "");
    legacy::u32v(out, kParamsFormatMarker);
    legacy::u32v(out, 3);
    legacy::u32v(out, 1);          // one zone
    legacy::strv(out, "kick");
    legacy::u32v(out, 0);          // lowNote
    legacy::u32v(out, 127);        // highNote
    legacy::u8v(out, 0);           // no root override
    legacy::u8v(out, 0);           // no loop override
    legacy::u8v(out, 0);           // no start point
    legacy::u8v(out, 0);           // playMode: Gate
    legacy::i64v(out, 2400);       // holdFrames -> 0.05 s at 48 kHz
    legacy::f64v(out, 1.0);        // lengthFraction
    legacy::i64v(out, 0);          // fadeIn
    legacy::i64v(out, 0);          // fadeOut
    legacy::u8v(out, 1);           // pitchEngine: Preserve
    legacy::u8v(out, 1);           // pitchEnv enabled
    legacy::i64v(out, 960);        // pitchEnv attackFrames -> 0.02 s
    legacy::i64v(out, 1440);       // pitchEnv decayFrames  -> 0.03 s
    legacy::f64v(out, 5.0);        // peakSemitones

    const ComponentState st = deserializeComponentState(out, 48000.0);
    CHECK(st.selectionId == "kick");
    CHECK(st.params.play.adsr.holdSeconds == 0.05);
    CHECK(st.params.play.pitchEnv.attackSeconds == 0.02);
    CHECK(st.params.play.pitchEnv.decaySeconds == 0.03);
    CHECK(st.params.play.pitchEnv.peakSemitones == 5.0);
    // A/D/S/R are absent in v3 -> the tier-0 seconds defaults hold.
    CHECK(st.params.play.adsr.attackSeconds == AdsrSeconds{}.attackSeconds);
    CHECK(st.params.play.adsr.releaseSeconds == AdsrSeconds{}.releaseSeconds);

    // The SAME bytes at a different project rate convert to different seconds — proof the
    // rate is a read-time parameter, not a baked constant.
    const ComponentState at96k = deserializeComponentState(out, 96000.0);
    CHECK(at96k.params.play.adsr.holdSeconds == 0.025);
}

// --- The ENVELOPE ladder (v2..v11) -------------------------------------------

// EVERY envelope version restores the fields it carried and lifts the ones it predates to
// their documented defaults. One table over the whole ladder, so a new envelope field
// cannot be added without deciding what each older version lifts it to.
static void testEnvelopeLadderLiftsEachVersion() {
    for (std::uint32_t v : {3u, 4u, 5u, 6u, 7u, 8u, 9u, 10u, 11u}) {
        legacy::Envelope env;
        env.version = v;
        env.selectionId = "kick";
        env.modeByte = 1;                 // stereo
        env.assignGeneration = 4242;
        env.previewVelocity = 99;
        env.voiceCount = 7;
        env.voiceMode = 1;                // mono
        env.monoTrigger = 1;              // legato
        env.masterGain = 0.5;
        env.channelModeExplicit = 1;
        env.instanceGuid = "guid-abc";
        const ComponentState out =
            deserializeComponentState(legacy::envelopeWithZones(env, {}, 7), 48000.0);

        CHECK(out.selectionId == "kick");   // v3 onward all carry the selection
        // v4 added the channel mode; older blobs lift to MONO.
        CHECK(out.channelMode == (v >= 4 ? ChannelMode::Stereo : ChannelMode::Mono));
        // v5 added the consumed-assignment marker; older blobs lift to 0, so a genuinely
        // new first assign (generation >= 1) still applies to a pre-marker instance.
        CHECK(out.lastConsumedAssignGeneration == (v >= 5 ? 4242 : 0));
        // v6 added the preview velocity; older blobs lift to the mid default.
        CHECK(out.previewVelocity == (v >= 6 ? 99 : kPreviewVelocityDefault));
        // v7 added the voice system; older blobs lift to {16, Poly, Retrigger} — the
        // pre-voice-system behavior, byte-identically.
        CHECK(out.voiceCount == (v >= 7 ? 7 : kDefaultVoiceCount));
        CHECK(out.voiceMode == (v >= 7 ? VoiceMode::Mono : VoiceMode::Poly));
        CHECK(out.monoTrigger == (v >= 7 ? MonoTrigger::Legato : MonoTrigger::Retrigger));
        // v8 added the master gain; older blobs lift to unity.
        CHECK(out.masterGainLinear == (v >= 8 ? 0.5 : 1.0));
        // v9 added the channel-mode EXPLICIT flag; older blobs lift to implicit, so the
        // auto-default may follow the loaded capture.
        CHECK(out.channelModeExplicit == (v >= 9 ? true : false));
        // v10 added the refs table (always empty here), v11 the instance guid; a pre-v11
        // blob lifts to an empty guid, which the processor mints on first publish.
        CHECK(out.instanceGuid == (v >= 11 ? "guid-abc" : ""));
        CHECK(out.sampleRefs.empty());
    }
}

// A v2 blob is ZONES-ONLY — no stored selection at all — so the adopted first zone supplies
// BOTH the capture and the parameters.
static void testV2ZonesOnlyBlobAdoptsBothFromZoneOne() {
    legacy::Zone z;
    z.sampleId = "kick";
    z.rootOverride = 36;
    std::vector<std::uint8_t> out;
    legacy::u32v(out, kPerformanceStateVersion);  // == 2, the zones-only envelope
    legacy::u32v(out, kParamsFormatMarker);
    legacy::u32v(out, 7);
    legacy::u32v(out, 1);
    legacy::putZone(out, z, 7);

    const ComponentState st = deserializeComponentState(out, 48000.0);
    CHECK(st.selectionId == "kick");
    CHECK(st.params.rootOverride && *st.params.rootOverride == 36);
    CHECK(st.channelMode == ChannelMode::Mono);  // a v2 blob predates the mode byte
}

// A CORRUPT field falls back to its own DEFAULT rather than clamping to an edge the user
// never chose (or, for the gain, silencing/blasting the instance).
static void testCorruptFieldsFallBackToDefaults() {
    legacy::Envelope env;
    env.selectionId = "kick";
    env.previewVelocity = 0;      // 0 is a note-off by convention — out of the 1..127 spec
    env.voiceCount = 200;         // past kMaxVoiceCount
    env.masterGain = 1e9;         // far past the +24 dB cap
    const ComponentState out =
        deserializeComponentState(legacy::envelopeWithZones(env, {}, 7), 48000.0);
    CHECK(out.previewVelocity == kPreviewVelocityDefault);
    CHECK(out.voiceCount == kDefaultVoiceCount);
    CHECK(out.masterGainLinear == 1.0);
}

// CORRUPT-BLOB posture for the refs-table intrinsics: the refs table is the ONLY copy on the
// play path, so a bad field must degrade to its own default, never poison playback. An
// out-of-MIDI-range rootNote falls back to the middle-C default distill() uses; a negative
// channelCount falls back to 0 = unknown (the GA auto-default then skips it). The fallback is
// per-field — in-range neighbours pass through untouched.
static void testSampleRefsReaderRangeFallbacks() {
    ComponentState s;
    s.sampleRefs.push_back(refEntry("hi", "b/h.wav", /*root=*/999, false, 0, 0,
                                    /*channels=*/-3));
    s.sampleRefs.push_back(refEntry("lo", "b/l.wav", /*root=*/-5, false, 0, 0,
                                    /*channels=*/1));
    s.sampleRefs.push_back(refEntry("ok", "b/o.wav", /*root=*/36, false, 0, 0,
                                    /*channels=*/2));
    const ComponentState back = deserializeComponentState(serializeComponentState(s), 44100.0);
    CHECK(back.sampleRefs.size() == 3);
    CHECK(back.sampleRefs.size() == 3 && back.sampleRefs[0].ref.rootNote == 60);
    CHECK(back.sampleRefs.size() == 3 && back.sampleRefs[0].ref.channelCount == 0);
    CHECK(back.sampleRefs.size() == 3 && back.sampleRefs[1].ref.rootNote == 60);
    CHECK(back.sampleRefs.size() == 3 && back.sampleRefs[1].ref.channelCount == 1);
    CHECK(back.sampleRefs.size() == 3 && back.sampleRefs[2].ref.rootNote == 36);
    CHECK(back.sampleRefs.size() == 3 && back.sampleRefs[2].ref.channelCount == 2);
}

// A blob cut mid-refs-entry keeps the entries that parsed cleanly and restores the rest of
// the state empty (the selection/params behind the cut are unreadable anyway) — the
// established truncation posture, never a throw across the host boundary.
static void testSampleRefsTruncatedMidEntry() {
    ComponentState s;
    s.selectionId = "kick";
    s.sampleRefs.push_back(refEntry("kick", "b/k.wav", 36));
    s.sampleRefs.push_back(refEntry("pad", "b/p.wav", 60));
    std::vector<std::uint8_t> bytes = serializeComponentState(s);
    // The tail after the refs table is instanceGuid(4, empty) + selectionId(4+4="kick") +
    // the current params payload for DEFAULT params (marker4+version4 + overrides3 + the
    // 91-byte play tail + keyTrack8 + curve(4+2*16, the flat 2-point default)) = 158 bytes;
    // entry two is 47 bytes (id 4+3, path 4+7, root4, loop 1+8+8, channels4, name 4+0).
    // Cutting 178 bytes keeps the first 27 of entry two's 47 — mid loop.start (offset 23..31).
    CHECK(bytes.size() > 178);
    bytes.resize(bytes.size() - 178);
    const ComponentState back = deserializeComponentState(bytes, 44100.0);
    CHECK(back.sampleRefs.size() == 1);
    CHECK(back.sampleRefs.size() == 1 && back.sampleRefs[0].sampleId == "kick");
    CHECK(back.selectionId.empty());
    CHECK(!back.params.rootOverride);
}

// The WRITER never emits an out-of-range voice count or master gain, so a blob this codec
// produced always re-reads as itself.
static void testWriterClampsOutOfRangeFields() {
    ComponentState in;
    in.voiceCount = 999;
    in.masterGainLinear = 1e9;
    const ComponentState out =
        deserializeComponentState(serializeComponentState(in), 48000.0);
    CHECK(out.voiceCount >= kMinVoiceCount && out.voiceCount <= kMaxVoiceCount);
    CHECK(out.masterGainLinear <=
          reasampler::instrument::engine::masterGainMaxLinear() * (1.0 + 1e-9));

    // Zero gain is TRUE silence and a legal stored value — it must not be "corrected".
    ComponentState silent;
    silent.masterGainLinear = 0.0;
    CHECK(deserializeComponentState(serializeComponentState(silent), 48000.0)
              .masterGainLinear == 0.0);
}

// An UNKNOWN envelope version yields the empty state rather than a misparse.
static void testUnknownEnvelopeVersionIsEmpty() {
    legacy::Envelope env;
    env.version = 99;
    env.selectionId = "kick";
    const ComponentState out =
        deserializeComponentState(legacy::envelopeWithZones(env, {}, 7), 48000.0);
    CHECK(out.selectionId.empty());
    CHECK(!out.params.rootOverride);
}

// A v1 selection blob lifts to {id, default params} — the oldest live lift.
static void testV1SelectionLift() {
    const std::vector<std::uint8_t> v1 = serializeSelection("old-pick");
    const ComponentState out = deserializeComponentState(v1, 48000.0);
    CHECK(out.selectionId == "old-pick");
    CHECK(!out.params.rootOverride);
    CHECK(out.params.keyTrack == 1.0);
}

// Truncation degrades to a partial/empty parse — never out-of-bounds, never throws. Run
// over BOTH the current format and a retired zone-list blob, since the migration path has
// its own bounded-read walk. Beyond mere survival, a cut read must never RETAIN more refs
// than the blob actually carried (the "keep what parsed, drop the rest" contract could not
// silently start fabricating entries) — see testSampleRefsTruncatedMidEntry for the exact
// mid-entry retention case this bounds only loosely across every cut point.
static void testTruncationDegradesCleanly() {
    ComponentState in;
    in.selectionId = "smp-2";
    in.params.rootOverride = 61;
    in.sampleRefs.push_back(refEntry("smp-2", "b/s.wav", 61));
    in.sampleRefs.push_back(refEntry("smp-3", "b/t.wav", 62));
    const std::vector<std::uint8_t> current = serializeComponentState(in);

    legacy::Zone z;
    z.sampleId = "smp-2";
    const std::vector<std::uint8_t> retired = legacy::envelopeWithZones("smp-2", {z, z}, 7);

    for (const std::vector<std::uint8_t>* blob : {&current, &retired}) {
        for (std::size_t cut = 0; cut < blob->size(); ++cut) {
            const std::vector<std::uint8_t> part(blob->begin(),
                                                 blob->begin() + static_cast<long>(cut));
            const ComponentState out = deserializeComponentState(part, 48000.0);
            CHECK(out.sampleRefs.size() <= in.sampleRefs.size());
        }
    }
}

int main() {
    testComponentStateRoundTrip();
    testGoldenFullBlobFixture();
    testDefaultStateRoundTripsToDefaults();
    testEnvelopePrefixBytesFrozen();
    testWriterEmitsCurrentPayloadVersion();
    testSingleZoneMigrationIsLossless();
    testSingleZoneMigrationLiftsLoopDisablingOverride();
    testLiftedStateReSavesInCurrentFormat();
    testMultiZoneMigrationAdoptsFirstZone();
    testFirstZoneSupersedesStoredSelection();
    testEmptyZoneListKeepsTheStoredSelection();
    testEveryOlderPayloadVersionMigrates();
    testLegacyV3FramesConvertAtTheProjectRate();
    testEnvelopeLadderLiftsEachVersion();
    testV2ZonesOnlyBlobAdoptsBothFromZoneOne();
    testCorruptFieldsFallBackToDefaults();
    testSampleRefsReaderRangeFallbacks();
    testSampleRefsTruncatedMidEntry();
    testWriterClampsOutOfRangeFields();
    testUnknownEnvelopeVersionIsEmpty();
    testV1SelectionLift();
    testTruncationDegradesCleanly();
    if (failures == 0) {
        std::printf("component_state_io_tests: all tests passed\n");
        return 0;
    }
    std::printf("component_state_io_tests: %d FAILURE(S)\n", failures);
    return 1;
}
