import * as Effect from "effect/Effect";
import entries from "../dist/catalog/catalog.ts";
import type { Artifact } from "./artifact-types.ts";
import { loadArtifact } from "./artifact.ts";
import { ArtifactUnavailable } from "./deployment-errors.ts";
import { sameRelease, type ReleaseIdentity } from "./installation-metadata.ts";

export type ArtifactLoader = (
  pinned?: ReleaseIdentity,
) => Effect.Effect<Artifact, ArtifactUnavailable>;

// Cache only successfully verified immutable artifacts, never a running fiber or
// rejected Promise owned by another request's lifetime.
const validated = new Map<string, Artifact>();
export function customerArtifact(
  pinned?: ReleaseIdentity,
  development = false,
) {
  return Effect.gen(function* () {
    const entry = entries.at(-1);
    if (
      entries.length !== 1 ||
      !entry ||
      (pinned && !sameRelease(entry.identity, pinned))
    )
      return yield* new ArtifactUnavailable();
    const key = entry.identity.artifactDigest + ":" + development;
    const cached = validated.get(key);
    if (cached) return cached;
    const artifact = yield* loadArtifact(entry, pinned, development);
    validated.set(key, artifact);
    return artifact;
  });
}