reasampler/tests/test_envelope_edit.cpp

// Standalone tests for reasampler::instrument::ui::envelope_edit — no VST3, no REAPER, no
// framework. Same fast assert loop as the sibling pure tests. Assert the INVERSE (edit) map
// against envelope_overlay's forward map: a grab lands on the node that was drawn there, and a
// pixel delta produces exactly the param a knob would have.
//
// Covers: nodeAtPoint (every drawn handle grabbable, the anchored ReleaseEnd and the Origin
// never grabbed, other-kind nodes rejected, misses outside the radius); resolveNodeDrag
// (AHDSR stage times at the schematic scale, the sustain level on Y, the release dragged from
// its START with the inverted sign, the caller's clamp domain, AHD stage times at the 1:1
// scale, the hold FRACTION); curve-knot drags (the exponent domain, its endpoints, and the
// round trip through the shared law that keeps knot and dial on one value); degenerate no-ops.

#include "../src/core/instrument/ui/envelope_edit.h"

#include <cmath>
#include <cstdio>
#include <vector>

using namespace reasampler;
using namespace reasampler::instrument::ui;

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

static OverlayArea overlayOf(const Rect& r) { return OverlayArea{r}; }
static Rect wideArea() { return Rect::ltrb(20, 10, 1020, 110); }  // width 1000, height 100
static constexpr double kTotal = 4.0;

static EnvClampBounds bounds() {
    EnvClampBounds b;
    b.maxAttackSeconds = 2.0;
    b.maxHoldSeconds = 2.0;
    b.maxDecaySeconds = 2.0;
    b.maxReleaseSeconds = 2.0;
    return b;
}

static StageEnvelope ahdsrEnv() {
    StageEnvelope e;
    e.kind = EnvKind::Ahdsr;
    e.attackSeconds = 0.3;
    e.holdSeconds = 0.2;
    e.decaySeconds = 0.4;
    e.sustainLevel = 0.6;
    e.releaseSeconds = 0.5;
    return e;
}

static StageEnvelope ahdEnv() {
    StageEnvelope e;
    e.kind = EnvKind::Ahd;
    e.attackSeconds = 0.4;
    e.decaySeconds = 0.6;
    e.holdFraction = 0.5;
    e.originSeconds = 0.0;
    e.spanSeconds = 3.0;
    return e;
}

static bool findNode(const std::vector<EnvVertex>& poly, EnvNode node, EnvVertex& out) {
    for (const EnvVertex& v : poly) {
        if (v.node == node) { out = v; return true; }
    }
    return false;
}

// Grab exactly where the forward map drew the node.
static NodeHit grabAt(const StageEnvelope& e, EnvNode node) {
    const Rect a = wideArea();
    EnvVertex v;
    if (!findNode(buildEnvelopePolyline(e, overlayOf(a), kTotal), node, v)) return NodeHit{};
    return nodeAtPoint(e, overlayOf(a), kTotal, v.x, v.y);
}

// --- hit-test ------------------------------------------------------------------

static void testEveryDrawnHandleIsGrabbable() {
    const StageEnvelope e = ahdsrEnv();
    const EnvNode want[] = {EnvNode::AttackEnd,    EnvNode::HoldEnd,     EnvNode::DecayEnd,
                            EnvNode::ReleaseStart, EnvNode::AttackCurve, EnvNode::DecayCurve,
                            EnvNode::ReleaseCurve};
    for (EnvNode n : want) {
        const NodeHit h = grabAt(e, n);
        CHECK(h.hit);
        CHECK(h.node == n);
    }
}

static void testAnchoredEndAndOriginAreNotGrabbable() {
    const StageEnvelope e = ahdsrEnv();
    const Rect a = wideArea();
    const std::vector<EnvVertex> poly = buildEnvelopePolyline(e, overlayOf(a), kTotal);
    EnvVertex end;
    CHECK(findNode(poly, EnvNode::ReleaseEnd, end));
    // The bottom-right corner is fixed: a grab there either misses or resolves to a NEIGHBOUR,
    // never to ReleaseEnd itself.
    const NodeHit h = nodeAtPoint(e, overlayOf(a), kTotal, end.x, end.y);
    CHECK(!h.hit || h.node != EnvNode::ReleaseEnd);
    EnvVertex origin;
    CHECK(findNode(poly, EnvNode::Origin, origin));
    const NodeHit o = nodeAtPoint(e, overlayOf(a), kTotal, origin.x, origin.y);
    CHECK(!o.hit || o.node != EnvNode::Origin);
}

static void testAhdHasNoSustainNodes() {
    const StageEnvelope e = ahdEnv();
    CHECK(grabAt(e, EnvNode::AttackEnd).hit);
    CHECK(grabAt(e, EnvNode::HoldEnd).hit);
    CHECK(grabAt(e, EnvNode::DecayEnd).hit);
    // ReleaseStart is not drawn on an AHD at all, so there is nothing to grab.
    CHECK(!grabAt(e, EnvNode::ReleaseStart).hit);
    // And an explicit resolve of an other-kind node is a no-op rather than a stray write.
    const StageEnvelope out = resolveNodeDrag(e, EnvNode::ReleaseStart, overlayOf(wideArea()),
                                              kTotal, bounds(), 40, 0);
    CHECK(out.releaseSeconds == e.releaseSeconds);
    CHECK(out.attackSeconds == e.attackSeconds);
}

static void testMissOutsideTheRadius() {
    const StageEnvelope e = ahdsrEnv();
    const Rect a = wideArea();
    // Far from every handle in both axes.
    const NodeHit h = nodeAtPoint(e, overlayOf(a), kTotal, a.x + 3, a.bottom() - 40);
    CHECK(!h.hit);
}

// --- AHDSR drags ---------------------------------------------------------------

static void testAhdsrStageTimesTrackTheSchematicScale() {
    const Rect a = wideArea();
    const StageEnvelope e = ahdsrEnv();
    const double secPerPx = 1.0 / gatePxPerSecond(a);

    const StageEnvelope attack =
        resolveNodeDrag(e, EnvNode::AttackEnd, overlayOf(a), kTotal, bounds(), 50, 0);
    CHECK(std::fabs(attack.attackSeconds - (e.attackSeconds + 50 * secPerPx)) < 1e-9);
    CHECK(attack.holdSeconds == e.holdSeconds);  // only the dragged param moves

    const StageEnvelope hold =
        resolveNodeDrag(e, EnvNode::HoldEnd, overlayOf(a), kTotal, bounds(), -20, 0);
    CHECK(std::fabs(hold.holdSeconds - (e.holdSeconds - 20 * secPerPx)) < 1e-9);

    const StageEnvelope decay =
        resolveNodeDrag(e, EnvNode::DecayEnd, overlayOf(a), kTotal, bounds(), 30, 0);
    CHECK(std::fabs(decay.decaySeconds - (e.decaySeconds + 30 * secPerPx)) < 1e-9);
}

// The release is dragged from its TOP node and its end is anchored to the canvas edge, so
// pulling that node LEFT lengthens the release — the sign is inverted relative to every other
// stage.
static void testReleaseDragsFromItsStartWithInvertedSign() {
    const Rect a = wideArea();
    const StageEnvelope e = ahdsrEnv();
    const double secPerPx = 1.0 / gatePxPerSecond(a);
    const StageEnvelope longer =
        resolveNodeDrag(e, EnvNode::ReleaseStart, overlayOf(a), kTotal, bounds(), -40, 0);
    CHECK(std::fabs(longer.releaseSeconds - (e.releaseSeconds + 40 * secPerPx)) < 1e-9);
    const StageEnvelope shorter =
        resolveNodeDrag(e, EnvNode::ReleaseStart, overlayOf(a), kTotal, bounds(), 40, 0);
    CHECK(shorter.releaseSeconds < e.releaseSeconds);
}

static void testSustainLevelOnTheDecayNodesYAxis() {
    const Rect a = wideArea();
    const StageEnvelope e = ahdsrEnv();
    const double lvlPerPx = 1.0 / (a.height - 1);
    const StageEnvelope up =
        resolveNodeDrag(e, EnvNode::DecayEnd, overlayOf(a), kTotal, bounds(), 0, -10);
    CHECK(std::fabs(up.sustainLevel - (e.sustainLevel + 10 * lvlPerPx)) < 1e-9);
    // Clamped to [0,1] at both ends.
    CHECK(resolveNodeDrag(e, EnvNode::DecayEnd, overlayOf(a), kTotal, bounds(), 0, -10000)
              .sustainLevel == 1.0);
    CHECK(resolveNodeDrag(e, EnvNode::DecayEnd, overlayOf(a), kTotal, bounds(), 0, 10000)
              .sustainLevel == 0.0);
}

static void testStageTimesClampToTheKnobDomain() {
    const Rect a = wideArea();
    const StageEnvelope e = ahdsrEnv();
    CHECK(resolveNodeDrag(e, EnvNode::AttackEnd, overlayOf(a), kTotal, bounds(), 100000, 0)
              .attackSeconds == bounds().maxAttackSeconds);
    CHECK(resolveNodeDrag(e, EnvNode::AttackEnd, overlayOf(a), kTotal, bounds(), -100000, 0)
              .attackSeconds == 0.0);
}

// --- AHD drags -----------------------------------------------------------------

static void testAhdStageTimesTrackTheWallClockScale() {
    const Rect a = wideArea();
    const StageEnvelope e = ahdEnv();
    const double secPerPx = kTotal / a.width;
    const StageEnvelope attack =
        resolveNodeDrag(e, EnvNode::AttackEnd, overlayOf(a), kTotal, bounds(), 100, 0);
    CHECK(std::fabs(attack.attackSeconds - (e.attackSeconds + 100 * secPerPx)) < 1e-9);

    // DecayEnd's underlying param (decaySeconds) does NOT move 1:1 with the cursor: the drawn
    // endpoint is t0 + total, and Hold eats a holdFraction share of whatever decay gives up
    // (d(total)/d(decay) = 1 - holdFraction), so decaySeconds itself has to move faster than
    // the cursor to make the DRAWN node track it. Assert on the RENDERED position, not the
    // raw param — that is the property a drag actually has to deliver, and asserting the old
    // 1:1 param delta here is exactly what let the node-tracking defect through undetected.
    EnvVertex before;
    CHECK(findNode(buildEnvelopePolyline(e, overlayOf(a), kTotal), EnvNode::DecayEnd, before));
    const StageEnvelope decay =
        resolveNodeDrag(e, EnvNode::DecayEnd, overlayOf(a), kTotal, bounds(), 100, 0);
    EnvVertex after;
    CHECK(findNode(buildEnvelopePolyline(decay, overlayOf(a), kTotal), EnvNode::DecayEnd, after));
    CHECK(std::abs((after.x - before.x) - 100) <= 1);  // 1:1 with the cursor, to rounding
}

// Hold is a fraction of what attack and decay left, so the node's pixel motion converts through
// that remainder — and the fraction can never leave [0,1], which is what keeps the sum bounded.
static void testAhdHoldNodeEditsTheFraction() {
    const Rect a = wideArea();
    const StageEnvelope e = ahdEnv();
    const double secPerPx = kTotal / a.width;
    const AhdSplit s = splitAhdSeconds(e);
    const double rem = e.spanSeconds - s.attack - s.decay;
    const StageEnvelope moved =
        resolveNodeDrag(e, EnvNode::HoldEnd, overlayOf(a), kTotal, bounds(), 100, 0);
    CHECK(std::fabs(moved.holdFraction - ((s.hold + 100 * secPerPx) / rem)) < 1e-9);
    CHECK(resolveNodeDrag(e, EnvNode::HoldEnd, overlayOf(a), kTotal, bounds(), 100000, 0)
              .holdFraction == 1.0);
    CHECK(resolveNodeDrag(e, EnvNode::HoldEnd, overlayOf(a), kTotal, bounds(), -100000, 0)
              .holdFraction == 0.0);
}

// --- curve knots ---------------------------------------------------------------

static void testKnotDragMovesTheExponentWithinItsDomain() {
    const Rect a = wideArea();
    StageEnvelope e = ahdsrEnv();
    e.attackCurve = util::kCurveNeutral;
    const StageEnvelope up =
        resolveNodeDrag(e, EnvNode::AttackCurve, overlayOf(a), kTotal, bounds(), 0, -12);
    const StageEnvelope down =
        resolveNodeDrag(e, EnvNode::AttackCurve, overlayOf(a), kTotal, bounds(), 0, 12);
    // Dragging the attack knot UP (toward the ceiling) is a faster-rising, SMALLER exponent.
    CHECK(up.attackCurve < util::kCurveNeutral);
    CHECK(down.attackCurve > util::kCurveNeutral);
    CHECK(up.attackCurve >= util::kCurveMin && up.attackCurve <= util::kCurveMax);
    CHECK(down.attackCurve >= util::kCurveMin && down.attackCurve <= util::kCurveMax);
    // Extreme drags saturate at the domain endpoints rather than escaping them.
    CHECK(resolveNodeDrag(e, EnvNode::AttackCurve, overlayOf(a), kTotal, bounds(), 0, -100000)
              .attackCurve == util::kCurveMin);
    CHECK(resolveNodeDrag(e, EnvNode::AttackCurve, overlayOf(a), kTotal, bounds(), 0, 100000)
              .attackCurve == util::kCurveMax);
    // Only the dragged segment's exponent moves.
    CHECK(up.decayCurve == e.decayCurve && up.releaseCurve == e.releaseCurve);
    CHECK(up.attackSeconds == e.attackSeconds);
}

// The one-model rule, asserted structurally: the drawn knot's height IS the shared law's
// reading of the stored exponent, and a zero-delta drag from that grab reproduces the exponent
// exactly — so the overlay and the inner dial cannot express different values for one field.
static void testKnotAndModelCannotDiverge() {
    const Rect a = wideArea();
    for (double exp : {0.2, 0.5, 1.0, 2.0, 7.0}) {
        StageEnvelope e = ahdsrEnv();
        e.attackCurve = exp;
        EnvVertex knot;
        CHECK(findNode(buildEnvelopePolyline(e, overlayOf(a), kTotal), EnvNode::AttackCurve,
                       knot));
        CHECK(std::fabs(knot.level - util::curveMidLevel(exp)) < 1e-12);
        const StageEnvelope same =
            resolveNodeDrag(e, EnvNode::AttackCurve, overlayOf(a), kTotal, bounds(), 0, 0);
        CHECK(std::fabs(same.attackCurve - exp) < 1e-9);
    }
}

// A decay into a sustain of exactly 1.0 is a LEVEL segment: there is no curve to express, so
// the drag must leave the exponent alone rather than divide by a zero level span.
static void testKnotOnALevelSegmentIsANoOp() {
    const Rect a = wideArea();
    StageEnvelope e = ahdsrEnv();
    e.sustainLevel = 1.0;
    e.decayCurve = 2.5;
    const StageEnvelope out =
        resolveNodeDrag(e, EnvNode::DecayCurve, overlayOf(a), kTotal, bounds(), 0, -30);
    CHECK(out.decayCurve == 2.5);
}

// A NEAR-level segment (sustain 0.99) is not caught by the exact-equality guard above, but its
// tiny divisor turns a one-pixel drag into a saturating swing of the exponent — the drag must
// still be a no-op rather than slam to a domain endpoint.
static void testKnotOnANearLevelSegmentIsANoOp() {
    const Rect a = wideArea();
    StageEnvelope e = ahdsrEnv();
    e.sustainLevel = 0.99;
    e.decayCurve = 2.5;
    const StageEnvelope out =
        resolveNodeDrag(e, EnvNode::DecayCurve, overlayOf(a), kTotal, bounds(), 0, -1);
    CHECK(out.decayCurve == 2.5);
}

// --- degenerate ----------------------------------------------------------------

static void testDegenerateInputsAreNoOps() {
    const StageEnvelope e = ahdsrEnv();
    const StageEnvelope zeroArea =
        resolveNodeDrag(e, EnvNode::AttackEnd, overlayOf(Rect{}), kTotal, bounds(), 50, 0);
    CHECK(zeroArea.attackSeconds == e.attackSeconds);
    const StageEnvelope zeroDur =
        resolveNodeDrag(e, EnvNode::AttackEnd, overlayOf(wideArea()), 0.0, bounds(), 50, 0);
    CHECK(zeroDur.attackSeconds == e.attackSeconds);
}

int main() {
    testEveryDrawnHandleIsGrabbable();
    testAnchoredEndAndOriginAreNotGrabbable();
    testAhdHasNoSustainNodes();
    testMissOutsideTheRadius();

    testAhdsrStageTimesTrackTheSchematicScale();
    testReleaseDragsFromItsStartWithInvertedSign();
    testSustainLevelOnTheDecayNodesYAxis();
    testStageTimesClampToTheKnobDomain();

    testAhdStageTimesTrackTheWallClockScale();
    testAhdHoldNodeEditsTheFraction();

    testKnotDragMovesTheExponentWithinItsDomain();
    testKnotAndModelCannotDiverge();
    testKnotOnALevelSegmentIsANoOp();
    testKnotOnANearLevelSegmentIsANoOp();

    testDegenerateInputsAreNoOps();

    if (g_fail == 0) std::printf("envelope_edit: all tests passed\n");
    else std::printf("envelope_edit: %d FAILED\n", g_fail);
    return g_fail == 0 ? 0 : 1;
}