import type { ParticlesAsset } from '../core/model/Asset';
import { graphFingerprint } from '../core/graph/Graph';
import { compileParticles, type ParticlesBuild } from '../core/particles/compile';
import { gameClock } from '../core/time';

/**
 * Compiled particle graphs, one per asset, recompiled when the graph's content changes – the same
 * contract the `ShaderLibrary` keeps, including its own freeze so a test can hold particle time
 * still without freezing the shaders too.
 */
export class ParticleLibrary {
  private readonly builds = new Map<string, { fingerprint: string; build: ParticlesBuild }>();
  /** How often a graph went through the compiler – what the checks read to prove a move did not. */
  compiles = 0;
  private frozenAt: number | null = null;

  /** The clock every source's age is measured on: the global one, so a pause reaches the fields. */
  now(): number {
    return this.frozenAt ?? gameClock.now;
  }

  freezeTime(at: number | null): void {
    this.frozenAt = at;
  }

  buildFor(asset: ParticlesAsset): ParticlesBuild {
    const fingerprint = graphFingerprint(asset.graph);
    const cached = this.builds.get(asset.id);
    if (cached && cached.fingerprint === fingerprint) return cached.build;
    this.compiles += 1;
    const build = compileParticles(asset.graph);
    this.builds.set(asset.id, { fingerprint, build });
    return build;
  }
}

export const particleLibrary = new ParticleLibrary();