feat: ✨ package retrieval api

src/packages/package.ts

@@ -0,0 +1,94 @@
+import { type Octokit } from "octokit";
+import { SemVer, parse } from "semver";
+import { createWriteStream } from "fs";
+import { type IncomingMessage } from "http";
+import { get as httpsGet } from "https";
+
+export interface PackageIdentifier {
+  /**
+   * does not include @ sign
+   * @example lemlib
+   */
+  readonly owner: string;
+  /**
+   * @example lemlib
+   */
+  readonly repo: string;
+}
+export type PackageReleaseData = Awaited<
+  ReturnType<Octokit["rest"]["repos"]["listReleases"]>
+>["data"][number];
+
+export class PackageVersion extends SemVer {
+  protected constructor(
+    protected readonly client: Octokit,
+    public readonly packId: PackageIdentifier,
+    public readonly data: PackageReleaseData,
+    version: SemVer,
+  ) {
+    super(version);
+  }
+
+  public static create(
+    client: Octokit,
+    packId: PackageIdentifier,
+    data: PackageReleaseData,
+  ): PackageVersion | null {
+    const version = parse(data.tag_name);
+    if (version == null) return null;
+    return new PackageVersion(client, packId, data, version);
+  }
+
+  public async download(
+    path: Path,
+    asset: { index: number } | { id: number } = { index: 0 },
+  ): Promise<boolean> {
+    try {
+      let index: number;
+      if ("index" in asset) index = asset.index;
+      else index = this.data.assets.findIndex((a) => a.id === asset.id);
+
+      const response = await new Promise<IncomingMessage>((resolve) =>
+        httpsGet(this.data.assets[index].url, resolve),
+      );
+      const fileStream = createWriteStream(path);
+
+      response.pipe(fileStream);
+      return true;
+    } catch (err) {
+      return false;
+    }
+  }
+}
+
+export class Package {
+  constructor(
+    protected readonly id: PackageIdentifier,
+    protected readonly client: Octokit,
+  ) {}
+
+  public async getVersions(): Promise<PackageVersion[]> {
+    return (
+      await this.client.rest.repos.listReleases({
+        ...this.id,
+      })
+    ).data
+      .map((release) => PackageVersion.create(this.client, this.id, release))
+      .filter((release): release is PackageVersion => release != null);
+  }
+
+  public async getLatest(): Promise<PackageVersion | null> {
+    return PackageVersion.create(
+      this.client,
+      this.id,
+      (
+        await this.client.rest.repos.getLatestRelease({
+          ...this.id,
+        })
+      ).data,
+    );
+  }
+}
+
+/** placeholder */
+type Path = string & { __type: "path" };