// spline_edit.h — the point-editing grammar's CLICK resolution: add/grab/delete/toggle from a
// single (x, y), plus resolveWaveformClaim, the waveform overlay's cross-affordance arbitration
// (node vs. crossfade tab vs. marker). Both spline consumers — the velocity-curve popup and the
// spline EG overlay — route their mouse-down through the click grammar, so the two cannot drift
// apart. Decision logic only, no host types, no drawing; mirror of envelope_edit otherwise.

#pragma once

#include <cstdint>

#include "core/instrument/engine/velocity_curve.h"
#include "core/instrument/ui/editor_geometry.h"  // Rect / OverlayArea

namespace reasampler::instrument::ui {

using engine::VelocityCurve;

// The gesture, in the pure module's own vocabulary (the shell maps its modifier state onto it).
enum class SplineGesture { kLeft, kRight, kControlLeft };

// What the gesture resolves to. Left-click adds a point in empty space and grabs an existing
// one; right-click deletes; control-click toggles hard/smooth. Points are smooth by default.
enum class SplineEditKind { kNone, kGrab, kAdd, kDelete, kToggleHard };

struct SplineEdit {
    SplineEditKind kind = SplineEditKind::kNone;
    int index = -1;  // the point the action targets; -1 for kAdd (it has none yet) and kNone
};

// Resolves a click at (x, y) over `box` into an edit. The endpoint and point-count rules are
// NOT re-stated here — kDelete on an endpoint and kAdd at the ceiling are refused by
// VelocityCurve::deletePoint / addPoint, which the caller applies, so there is exactly one home
// for each. A click outside the mapping box resolves to kNone unless it lands on a node's pick
// radius: the drawn inset ring must not ADD (the new point would clamp onto an endpoint's x and
// stack an undeletable duplicate) but must still be able to grab.
SplineEdit resolveSplineEdit(const VelocityCurve& curve, const VelocityCurve::Box& box,
                             SplineGesture gesture, int x, int y);

// The contour's mapping box inside the waveform overlay: the FULL area, so the drawn contour
// spans the whole sample width 1:1 with its time axis. No inset — unlike the popup's box, which
// insets to keep endpoint handles clear of the sheet border, this one must stay 1:1 with the
// waveform beneath it. Takes the overlay (not a lane) — see waveform_view.h's overlay contract.
VelocityCurve::Box splineOverlayBox(const OverlayArea& area);

// Two more rules complete the grammar. Both are enforced in the shell — mouse-tracking / drag
// state has no home in a pure module — and recorded here as their one home rather than restated
// at each call site:
// - DRAG-OFF DELETE: releasing a grabbed node well outside its box deletes it (endpoints exempt,
//   per deletePoint's own refusal) — editor_input.cpp's onMouseUp, shared verbatim by the popup
//   and the overlay.
// - THE OVERLAY'S OUTSIDE-BOX EXCEPTION: resolveSplineEdit's own outside-box grab/toggle/delete
//   allowance (above) is meant for the popup's inset ring; the overlay narrows it back to
//   strictly in-box, since splineOverlayBox has no inset — editor_input_waveform.cpp's
//   splineOverlayClick.

// One arbitration candidate: whether the affordance was hit under the cursor, and its own
// pick-target area (nominal, per its own module's constants — not the actual clipped pixel
// count; see resolveWaveformClaim).
struct WaveformClaim {
    bool hit = false;
    std::int64_t area = 0;
};

// Which affordance a waveform-overlay click claims.
enum class WaveformClaimant { kNone, kNode, kTab, kMarker };

// The overlay's cross-affordance arbitration: a contour node (or, mutually exclusively, a
// staged envelope's drag node — both feed the same `node` slot), the loop crossfade tab, and a
// marker's full-height column can all claim the same pixel. Hit gates a candidate out
// entirely; among the ones that hit, the SMALLEST nominal area wins — the marker column is the
// odd one out (its target is the whole overlay height), so it only wins where nothing narrower
// also claims the click. Ties go to whichever is checked first: node, then tab, then marker —
// no live geometry produces a tie except tab-vs-marker, which the tab correctly wins (see
// editor_input_waveform.cpp's mouseDownWaveform for the live constants). A control-click has no
// tab/marker meaning (they answer plain grabs only), so it resolves to the node whenever the
// node is in the running, regardless of area.
WaveformClaimant resolveWaveformClaim(const WaveformClaim& node, const WaveformClaim& tab,
                                      const WaveformClaim& marker, SplineGesture gesture);

}  // namespace reasampler::instrument::ui