reasampler/src/core/instrument/ui/deck_groups.h

// deck_groups.h — WHICH groups the Sample face's knob deck carries and in what order, plus
// the control-id space they are built from. Pure data: knob_deck lays out whatever descriptors
// it is handed, and this module decides what those descriptors are, so the deck's signal-flow
// ordering is provable without a host.

#pragma once

#include <vector>

#include "core/instrument/engine/play_params.h"  // PlayMode (the mode-dependent group faces)
#include "core/instrument/ui/knob_deck.h"        // DeckGroupDesc

namespace reasampler::instrument::ui {

// Deck control ids. Opaque to knob_deck, resolved by the shell's hit-test and value binding.
// Runtime-only — nothing persists them, so the ordering here is free to change.
enum class DeckParam {
    kPlayMode = 0,   // Gate | Trigger toggle
    kPitchEngine,    // Varispeed | Preserve toggle
    kAttack,         // amp AHDSR attack  (Gate)
    kHold,           // amp AHDSR hold    (Gate)
    kDecay,          // amp AHDSR decay   (Gate)
    kSustain,        // amp AHDSR sustain (Gate)
    kRelease,        // amp AHDSR release (Gate)
    kTrigLength,     // Trigger play span, % of the post-start length
    kTrigAttack,     // amp AHD attack    (Trigger)
    kTrigHold,       // amp AHD hold, % of the span left after attack + decay
    kTrigDecay,      // amp AHD decay     (Trigger)
    kPitchEnvEnable, // AHD pitch envelope on|off
    kPitchEnvAttack,
    kPitchEnvHold,   // % of the span left after attack + decay
    kPitchEnvDecay,
    kPitchEnvDepth,  // AHD pitch depth in +/- semitones
    kKeyTrack,       // key-tracking 0..200% (lives on InstrumentParams, not PlaySeconds)
    // Filter. The four control positions map through filter_params' own laws; the three
    // depths are bipolar and centred at zero.
    kFilterEnable,   // filter on|off caption toggle
    kFilterMorph,    // morph position: high-pass .. low-pass
    kFilterCutoff,   // cutoff, log across the audio band
    kFilterQ,        // resonance
    kFilterDrive,    // in-loop drive depth
    kFilterModAmt,   // filter envelope -> cutoff, +/-100%
    kFilterVel,      // velocity -> cutoff, +/-100%
    kFilterKeyTrack, // note -> cutoff, 0..200%
    kFilterLaw,      // morph law row toggle: HP-BP-LP | HP-notch-LP
    kFilterEnvAttack,   // filter AHDSR (Gate)
    kFilterEnvHold,
    kFilterEnvDecay,
    kFilterEnvSustain,
    kFilterEnvRelease,
    kFilterTrigAttack,  // filter AHD (Trigger)
    kFilterTrigHold,
    kFilterTrigDecay,
    // Curve exponents. These never get a cell of their own — each is the INNER DIAL of the
    // stage knob it shapes (see curveParamFor), which is why only sloped stages have one.
    kAttackCurve,
    kDecayCurve,
    kReleaseCurve,
    kTrigAttackCurve,
    kTrigDecayCurve,
    kPitchEnvAttackCurve,
    kPitchEnvDecayCurve,
    kFilterEnvAttackCurve,
    kFilterEnvDecayCurve,
    kFilterEnvReleaseCurve,
    kFilterTrigAttackCurve,
    kFilterTrigDecayCurve,
    // Overlay selection radios — transient view state, not parameters.
    kAmpEnvSelect,
    kPitchEnvSelect,
    kFilterEnvSelect,
    // Deck-only controls: processor-side per-instance params — routed to the processor
    // setters, never through the parameter set.
    kVoiceCount,     // polyphony bound (1..32) — a stepped knob in the VOICE group
    kVoiceMode,      // Poly | Mono caption toggle (VOICE group)
    kMonoTrigger,    // Retrig | Legato row toggle (VOICE group; live only in Mono)
    kMasterGain,     // post-mixer master gain knob (-inf..+24 dB taper, MASTER group)
    kCount
};

// Deck group ids. Unscoped so the shell's caption switch reads against the plain `id` int
// knob_deck carries.
enum DeckGroupId {
    kGroupPitch = 0,
    kGroupPitchEnv,
    kGroupFilter,
    kGroupFilterEnv,
    kGroupAmpEnv,
    kGroupVoice,
    kGroupMaster,
};

// The deck's groups, left to right, in SIGNAL-FLOW order: pitch -> filter -> amp, then the
// two instance-wide groups. `playMode` picks the AMP and FILTER ENV groups' faces — AHDSR in
// Gate, AHD in Trigger — via knob_deck's blank-cell reservation (knob_deck.h) so a mode flip
// never reflows the neighbouring groups.
std::vector<DeckGroupDesc> sampleDeckGroups(PlayMode playMode);

// The curve-exponent control a stage knob's INNER DIAL edits, or kCount when the knob shapes
// no curve. THE one place the "every stage except Hold and Sustain is sloped" rule is written
// down: a knob with no entry here draws no inner dial and its inner region resolves as an
// ordinary knob grab.
DeckParam curveParamFor(DeckParam knob);

// Whether control `id` is delivered LIVE — straight to the voices that are already sounding —
// rather than through an instrument reload. The line is drawn at continuously-valued playback
// controls, so this is a routing decision at the editor's commit site rather than a property
// of any one knob; moving a control across the line is a change here and nowhere else.
//
// THE home for why each excluded control is excluded. Three continuous controls are outside
// the live set, plus every discrete toggle and the overlay radios:
//   - the discrete toggles (play mode, pitch engine, filter enable/law, pitch-envelope enable)
//     name a different sound rather than a different setting of one;
//   - the three capture-anchored overrides (root, loop span, start frame) name positions in
//     the decoded PCM;
//   - kKeyTrack and kFilterVel feed values a voice latches at note-on by design (the pitch
//     ratio and the velocity-curve result), so live delivery would retune or re-gain a note
//     already struck;
//   - kTrigLength resolves playEnd_, a fact about the note, not a setting of it;
//   - the overlay radios select what the editor DRAWS and reach no parameter at all.
// Both amp shapes are live: the Trigger fade pair that used to reload folded into the AHD and
// inherited its routing, so a Trigger-mode instance now tracks its amplitude knobs too.
bool isLiveDeckParam(DeckParam id);

// The editor drag kinds that can commit live, in this pure module's own vocabulary (the
// shell's DragKind maps onto it) so the WHOLE routing decision — not just the predicate — is
// testable without a host.
enum class LiveDragKind { kOther, kDeckKnob, kEnvNode };

// Whether a drag of `kind` commits live. A deck knob is live per isLiveDeckParam (negative ids
// are the shell's processor-side sentinels and out-of-range ids are not controls, so neither
// reaches the enum); an envelope-node drag is live in either mode, since every stage value it
// can reach — AHDSR or AHD, on any of the three envelopes — is itself live.
bool liveCommitFor(LiveDragKind kind, int paramId);

// Which envelope the waveform overlay draws and edits. Exclusive across the three envelope
// decks, and kNone is a valid resting state — the editor opens there. Transient view state:
// never persisted, never a parameter.
enum class OverlayEnv { kNone, kAmp, kPitch, kFilter };

// The envelope a deck's overlay-select radio picks; kNone for any other control id.
OverlayEnv overlayEnvForRadio(int radioId);

// The selection a click on `radioId` produces from `current`. Two rules, provable here rather
// than in the shell: picking another deck's radio switches to it (exclusivity), and clicking
// the ACTIVE one clears back to kNone — "no envelope shown" is a state the user can get back
// to, not an error. A non-radio id leaves the selection alone.
OverlayEnv nextOverlaySelection(OverlayEnv current, int radioId);

// Whether the overlay for `env` is INERT: its deck group's enable toggle is off, so its knobs
// are drawn-but-dead and a node drag on the same params must be too — otherwise a drag reaches
// a param a knob couldn't (envelope_edit.h). Amp has no enable toggle and is never inert.
bool overlayEnvInert(OverlayEnv env, bool pitchEnvEnabled, bool filterEnabled);

// The deck's BIPOLAR knob law: 0.5 of the knob's travel is zero depth, the ends are -1 and
// +1. Exact inverses, and exact at the centre detent (0.5 -> 0 -> 0.5), so a knob parked at
// centre can never persist a hair of modulation. Out-of-range norm clamps to the endpoints.
double deckBipolarFromNorm(double norm);
double deckNormFromBipolar(double value);

}  // namespace reasampler::instrument::ui