// editor_input_waveform.cpp — the WAVEFORM band's input: grabbing an envelope node or a
// start/loop marker, and resolving both drags live against the pure inverse maps
// (envelope_edit, waveform_view). Windows-only.
//
// Overlay contract: see waveform_view.h's WaveformSurface.

#include "shell/instrument/reasampler_editor.h"

#ifdef _WIN32

#include <algorithm>
#include <cstdint>
#include <vector>

#include "core/instrument/engine/loop/loop_span.h"  // maxCrossfade (the shared drag-clamp bound)
#include "core/instrument/ui/envelope_edit.h"   // nodeAtPoint / resolveNodeDrag
#include "core/instrument/ui/spline_edit.h"     // the shared point-editing grammar
#include "core/instrument/ui/waveform_view.h"   // waveformOverlayArea / markerAtPoint / snap
#include "shell/instrument/editor_internal.h"
#include "shell/instrument/reasampler_processor.h"

namespace reasampler::vst {

using namespace reasampler::ui;
using namespace reasampler::instrument::ui;
using instrument::engine::loop::maxCrossfade;

bool ReaSamplerEditor::mouseDownWaveform(const FaceLayout& fl, int x, int y) {
    const std::vector<AudioSample>& pcm = monoPcmFor(selectedId_);
    const std::int64_t frames = static_cast<std::int64_t>(pcm.size());
    if (frames <= 0) return false;
    const OverlayArea overlay = waveformOverlayArea(fl.bands.waveform);

    const DeckEnableState gates = deckEnableState();
    const bool splineLive = overlayIsSpline() && overlayEnvEnabled(overlayEnv_, gates);
    const SplineGesture gesture = (GetKeyState(VK_CONTROL) & 0x8000) != 0
                                      ? SplineGesture::kControlLeft
                                      : SplineGesture::kLeft;

    // Envelope nodes first (they sit on top of the markers), then the wave markers. With no
    // envelope overlay-active — or with its deck group's enable toggle off, which makes the
    // same params' knobs inert — there are no grabbable nodes and the markers take every grab.
    const double rate = liveSampleRate();
    const bool nodesLive =
        overlayEnv_ != OverlayEnv::kNone && !overlayEnvInert(overlayEnv_, gates);
    if (rate > 0.0 && nodesLive) {
        const std::int64_t startFrame = params_.startPoint.value_or(0);
        const StageEnvelope env = packEnvelope(overlayEnv_, params_.play, frames, startFrame);
        const double totalSeconds = static_cast<double>(frames) / rate;
        const NodeHit nh = nodeAtPoint(env, overlay, totalSeconds, x, y);
        if (nh.hit) {
            drag_ = DragKind::kEnvNode;
            envNode_ = nh.node;
            dragStartX_ = x;
            dragStartY_ = y;
            dragStartEnv_ = env;
            dragSampleFrames_ = frames;
            dragStartParams_ = params_;
            return true;  // node moves once the cursor drags
        }
    }
    // An existing contour node's grab/toggle/delete runs BEFORE the markers — mirroring
    // markerHandleRect's tab-vs-column split (below): a coincident pixel (the default contour
    // endpoint sits at the same x as the default start marker) is resolved by asking the
    // NARROWER target first. pointAtPixel's pick radius is a small box around the node's own
    // (x, y), not a full-height column, so this claims only genuine node hits — the marker's
    // column stays grabbable at every other y along the same x. Never add here (kAdd is only
    // tried once the markers have also passed on the click, below).
    if (splineLive && splineOverlayClick(overlay, x, y, gesture, /*addOnEmptySpace=*/false)) {
        return true;
    }

    const SetupMarkers m = pickedMarkers(frames);
    // The crossfade handle first, and only when there IS a loop to fade: at a zero fade it
    // sits exactly on the loop start, so it can only stay reachable by owning the top strip
    // (waveform_view.h's handle-vs-column split) and being asked first. The same ambiguity
    // recurs whenever ANY marker's frame lands on loopStart - crossfade (most plausibly the
    // start marker dragged up against the fade edge), so this check has to run before the
    // marker array below regardless of which marker the collision is with.
    if (m.hasLoop &&
        contains(markerHandleRect(overlay, frames, m.loopStart - m.crossfade), x, y)) {
        beginMarkerDrag(WaveMarker::kLoopXfade, m, frames, x);
        return true;
    }
    const std::int64_t markerFrames[3] = {m.start, m.loopStart, m.loopEnd};
    const int hit = markerAtPoint(overlay, frames, markerFrames, 3, x, y);
    if (hit >= 0) {
        beginMarkerDrag(static_cast<WaveMarker>(hit), m, frames, x);
        return true;
    }
    // Nothing else wanted the click: now the drawn contour may take the empty space.
    if (splineLive) return splineOverlayClick(overlay, x, y, gesture, /*addOnEmptySpace=*/true);
    return false;
}

bool ReaSamplerEditor::splineOverlayClick(const OverlayArea& waveArea, int x, int y,
                                          SplineGesture gesture, bool addOnEmptySpace) {
    const VelocityCurve::Box box = splineOverlayBox(waveArea);
    VelocityCurve& contour = splineFor(overlayEnv_);
    SplineEdit edit = resolveSplineEdit(contour, box, gesture, x, y);
    // resolveSplineEdit's outside-box grab/delete/toggle allowance (pointAtPixel's radius has
    // no box check of its own) was designed for the popup's inset ring; the overlay box has NO
    // inset (splineOverlayBox), so honoring it here would extend the grab halo 6px into the
    // inter-band pad. kAdd already requires in-box (resolveSplineEdit's own check).
    if (edit.kind != SplineEditKind::kNone && edit.kind != SplineEditKind::kAdd &&
        !(x >= box.left && x < box.left + box.width && y >= box.top && y < box.top + box.height)) {
        edit = SplineEdit{};
    }
    if (edit.kind == SplineEditKind::kAdd && !addOnEmptySpace) return false;
    switch (edit.kind) {
        case SplineEditKind::kNone:
            return false;
        case SplineEditKind::kDelete:
            // deletePoint refuses the two endpoints, so a right-click on one is a safe no-op.
            if (!contour.deletePoint(static_cast<std::size_t>(edit.index))) return true;
            hover_ = HoverTarget{};  // a stale index would light a shifted node
            commitAndReload();
            return true;
        case SplineEditKind::kToggleHard:
            if (!contour.toggleHard(static_cast<std::size_t>(edit.index))) return true;
            commitAndReload();
            return true;
        case SplineEditKind::kAdd:
        case SplineEditKind::kGrab:
            break;
    }
    // Snapshot BEFORE the add so a capture-loss rollback cancels the in-flight point too
    // (the same contract the other parameter-editing drags keep).
    dragStartParams_ = params_;
    int index = edit.index;
    if (edit.kind == SplineEditKind::kAdd) {
        const VelocityPoint p = contour.pointFromPixel(box, x, y);
        index = contour.addPoint(p.velocity, p.value);
        // At the ceiling: refused, contour untouched, nothing to roll back. Swallow the click
        // rather than letting it fall through to a marker grab under the cursor.
        if (index < 0) return true;
    }
    drag_ = DragKind::kSplineNode;
    curvePointIndex_ = index;
    dragStartCurve_ = contour;  // AFTER the add — resolvePointDrag's delta base
    // The release-time drag-off-delete bound (onMouseUp), matching the popup's kCurveNode use
    // of the same field — the two spline surfaces share one drag-off grammar, not just the
    // click grammar.
    dragCurveRect_ = waveArea.rect;
    dragStartX_ = x;
    dragStartY_ = y;
    invalidate();  // live feedback; the commit lands on WM_LBUTTONUP
    return true;
}

void ReaSamplerEditor::beginMarkerDrag(WaveMarker which, const SetupMarkers& m,
                                       std::int64_t frames, int x) {
    drag_ = DragKind::kWaveMarker;
    waveMarker_ = which;
    dragStartX_ = x;
    dragStartMarkers_ = m;
    dragSampleFrames_ = frames;
    dragStartParams_ = params_;
}

void ReaSamplerEditor::dragWaveform(const FaceLayout& fl, int x, int y) {
    const OverlayArea overlay = waveformOverlayArea(fl.bands.waveform);
    const int dx = x - dragStartX_;

    if (drag_ == DragKind::kSplineNode) {
        // Same absolute-delta contract as the popup's node drag, against the grab-time contour
        // and the overlay's own box.
        if (curvePointIndex_ < 0) return;
        splineFor(overlayEnv_) = VelocityCurve::resolvePointDrag(
            dragStartCurve_, static_cast<std::size_t>(curvePointIndex_),
            splineOverlayBox(overlay), dx, y - dragStartY_);
        invalidate();  // live feedback; commit on release
        return;
    }

    if (drag_ == DragKind::kEnvNode) {
        // Resolve the grabbed envelope node's new params from the pixel delta (through the
        // pure envelope_edit inverse map, clamped), then unpack them back onto the parameter
        // set. The StageEnvelope was snapshotted at grab (dragStartEnv_) so the delta is
        // absolute.
        const std::int64_t frames = dragSampleFrames_;
        const double rate = liveSampleRate();
        if (frames <= 0 || rate <= 0.0) return;
        const double totalSeconds = static_cast<double>(frames) / rate;
        const StageEnvelope edited = resolveNodeDrag(dragStartEnv_, envNode_, overlay,
                                                     totalSeconds, envClampBounds(), dx,
                                                     y - dragStartY_);
        unpackEnvelope(overlayEnv_, edited, params_.play);
        if (dragCommitsLive(DragKind::kEnvNode)) commitLive();
        invalidate();  // live feedback; commit on WM_LBUTTONUP
        return;
    }

    // kWaveMarker: resolve the grabbed marker's new frame from the pixel delta,
    // zero-crossing-snap it against the decoded PCM, apply the inter-marker clamps, and write
    // the override live.
    const std::int64_t frames = dragSampleFrames_;
    if (frames <= 0) return;

    // Grabbed frame at grab time, from the snapshot (so the delta is measured from grab).
    const int idx = static_cast<int>(waveMarker_);
    const std::int64_t startVals[4] = {dragStartMarkers_.start, dragStartMarkers_.loopStart,
                                       dragStartMarkers_.loopEnd,
                                       dragStartMarkers_.loopStart -
                                           dragStartMarkers_.crossfade};
    std::int64_t newFrame = resolveDragFrame(overlay, frames, startVals[idx], dx);

    // Snap to the nearest zero crossing in the decoded PCM. Pure over the cached mono
    // frames — no host types, no file I/O. The crossfade handle is exempt: it sets a fade
    // LENGTH, and the whole point of the fade is that its edges need no zero crossing.
    const std::vector<AudioSample>& pcm = monoPcmFor(selectedId_);
    if (!pcm.empty() && waveMarker_ != WaveMarker::kLoopXfade) {
        newFrame = nearestZeroCrossing(pcm.data(), static_cast<std::int64_t>(pcm.size()),
                                       newFrame);
    }

    // Build the edited marker set from the snapshot, moving only the grabbed marker, then
    // clamp: loopStart <= loopEnd, start in [0, frames-1]. Dragging a loop marker MAKES a loop.
    SetupMarkers m = dragStartMarkers_;
    if (waveMarker_ == WaveMarker::kStart) {
        m.start = newFrame;
    } else if (waveMarker_ == WaveMarker::kLoopStart) {
        m.loopStart = (std::min)(newFrame, m.loopEnd);
        m.hasLoop = true;
    } else if (waveMarker_ == WaveMarker::kLoopEnd) {
        m.loopEnd = (std::max)(newFrame, m.loopStart);
        m.hasLoop = true;
    } else {  // kLoopXfade — the handle sits at loopStart - crossfade, so left lengthens it
        m.crossfade = (std::max)(std::int64_t{0}, m.loopStart - newFrame);
    }
    if (m.start < 0) m.start = 0;
    if (m.start > frames - 1) m.start = frames - 1;
    // Shares resolveLoop's own bound (loop_span.h's maxCrossfade) so the handle can't be
    // dragged somewhere the engine would silently clamp back.
    m.crossfade = (std::min)(m.crossfade, maxCrossfade(m.loopStart, m.loopEnd - m.loopStart));
    if (m.crossfade < 0) m.crossfade = 0;

    applyMarkers(m);
    invalidate();  // live feedback; the commit lands on release
}

}  // namespace reasampler::vst

#endif  // _WIN32