/**
 * What a scene *is*: a list of vibrating objects, a body for them to sound
 * over, and nothing else. Everything the app builds — the generated model .m,
 * the generated scene .m, the op instances, the sliders — is derived from
 * this description (src/studio/codegen.ts), so this file is the studio's
 * whole vocabulary.
 *
 * Two kinds of number live here, and the split decides what an edit costs:
 *
 *  - `size` fields are baked into the grids and the coupling ops, so changing
 *    one recompiles (a fresh session, like changing the air grid).
 *  - `params` (model parameters: pitches, decays, gains) are GPU uniforms —
 *    free to move — and `place` (placement in the air: an object's y offset
 *    and height, the body's shape) are scene parameters, which cost one CPU
 *    re-evaluation of the scene .m and a few buffer uploads. Neither
 *    recompiles.
 *
 * Object ids are short and stable ('s1', 'm2'); the code generator suffixes
 * every per-object name with them, so the generated MATLAB stays readable in
 * the Lab view.
 */

export type Params = Record<string, number>;

/** A tunable scalar and its slider. */
export interface ParamSpec {
  key: string;
  label: string;
  value: number;
  min: number;
  max: number;
  step: number;
  /** Shown as a tooltip. */
  hint?: string;
  /** Shown in the Play layer (the handful of knobs a player would reach
   *  for); everything else appears only in Build. */
  musical?: boolean;
}

export type ObjectType = 'string' | 'bar' | 'membrane';

export interface ObjectSpec {
  /** Unique in the scene: 's1', 'b1', 'm1', ... */
  id: string;
  type: ObjectType;
  /** Baked extents, metres: L1 along x (and L2 along y, for a membrane). */
  size: { L1: number; L2?: number };
  /** Model parameter values, by unsuffixed key (f0, t60, ...). */
  params: Params;
  /** Placement values, by unsuffixed key (oy, oz). Scene parameters. */
  place: Params;
}

export type BodyType = 'none' | 'box' | 'shell';

export interface BodySpec {
  type: BodyType;
  params: Params;
}

export interface SceneSpec {
  objects: ObjectSpec[];
  body: BodySpec;
}

export const defaultsOf = (specs: ParamSpec[]): Params =>
  Object.fromEntries(specs.map((p) => [p.key, p.value]));

/** The suffixed name a per-object thing gets in the generated MATLAB. */
export const suffixed = (key: string, id: string): string => `${key}_${id}`;