Fail fast on missing terrain assets and recover empty renders

scripts/assets.mjs

@@ -1,36 +1,90 @@
-import { mkdir, readFile, writeFile, access } from "node:fs/promises";
+import { mkdir, readFile, writeFile } from "node:fs/promises";
 import { createHash } from "node:crypto";
 import { unzipSync } from "fflate";
 export const assetsRoot = ".cache/minecraft/1.21.11";
-export async function prepareAssets() {
+const completionMarker = `${assetsRoot}/.minegeo-assets.json`;
+const requiredAssets = [
+  "blockstates/grass_block.json",
+  "blockstates/stone.json",
+  "models/block/block.json",
+  "models/block/cube.json",
+  "models/block/cube_all.json",
+  "textures/block/grass_block_top.png",
+  "textures/block/dirt.png",
+  "textures/block/stone.png",
+  "textures/block/water_still.png",
+];
+async function assetsReady() {
   try {
-    await access(`${assetsRoot}/assets/minecraft/blockstates/grass_block.json`);
-    return;
-  } catch {}
+    const marker = JSON.parse(await readFile(completionMarker, "utf8"));
+    if (
+      marker.format !== "minegeo-assets/v1" ||
+      marker.minecraftVersion !== "1.21.11" ||
+      !marker.files
+    )
+      return false;
+    // A blockstate alone is insufficient: interrupted setup can leave models
+    // and textures absent. The marker is only written after all extraction.
+    for (const asset of requiredAssets) {
+      const bytes = await readFile(`${assetsRoot}/assets/minecraft/${asset}`);
+      if (asset.endsWith(".json")) JSON.parse(bytes.toString());
+      else if (
+        bytes.length < 8 ||
+        bytes.subarray(0, 8).toString("hex") !== "89504e470d0a1a0a"
+      )
+        return false;
+    }
+    return true;
+  } catch {
+    return false;
+  }
+}
+export async function prepareAssets() {
+  if (await assetsReady()) return;
+  console.log(
+    "Preparing Minecraft 1.21.11 models and textures for terrain rendering…",
+  );
   const manifest = await (
     await fetch(
       "https://piston-meta.mojang.com/mc/game/version_manifest_v2.json",
+      { signal: AbortSignal.timeout(60000) },
     )
   ).json();
   const entry = manifest.versions.find((v) => v.id === "1.21.11");
   if (!entry) throw new Error("Official Minecraft 1.21.11 metadata missing");
-  const version = await (await fetch(entry.url)).json();
+  const version = await (
+    await fetch(entry.url, { signal: AbortSignal.timeout(60000) })
+  ).json();
   await mkdir(".cache/minecraft", { recursive: true });
   const jarPath = ".cache/minecraft/client-1.21.11.jar";
   let jar;
   try {
     jar = await readFile(jarPath);
   } catch {
-    const response = await fetch(version.downloads.client.url);
-    if (!response.ok) throw new Error("Minecraft asset download failed");
-    jar = Buffer.from(await response.arrayBuffer());
-    await writeFile(jarPath, jar);
+    /* No cached client yet. */
   }
   if (
+    !jar ||
     createHash("sha1").update(jar).digest("hex") !==
-    version.downloads.client.sha1
-  )
-    throw new Error("Minecraft client checksum mismatch");
+      version.downloads.client.sha1
+  ) {
+    const response = await fetch(version.downloads.client.url, {
+      signal: AbortSignal.timeout(120000),
+    });
+    if (!response.ok)
+      throw new Error(
+        `Minecraft asset download failed: HTTP ${response.status}`,
+      );
+    jar = Buffer.from(await response.arrayBuffer());
+    if (
+      createHash("sha1").update(jar).digest("hex") !==
+      version.downloads.client.sha1
+    )
+      throw new Error(
+        "Minecraft client checksum mismatch; downloaded assets were not saved",
+      );
+    await writeFile(jarPath, jar);
+  }
   const entries = unzipSync(jar, {
     filter: (f) =>
       /^assets\/minecraft\/(models|blockstates|textures\/block)\//.test(
@@ -42,6 +96,20 @@ export async function prepareAssets() {
     await mkdir(path.slice(0, path.lastIndexOf("/")), { recursive: true });
     await writeFile(path, bytes);
   }
+  // Completion is recorded last, so a killed extraction is repaired next time.
+  await writeFile(
+    completionMarker,
+    JSON.stringify({
+      format: "minegeo-assets/v1",
+      minecraftVersion: "1.21.11",
+      clientSha1: version.downloads.client.sha1,
+      files: Object.keys(entries).length,
+    }),
+  );
+  if (!(await assetsReady()))
+    throw new Error(
+      "Minecraft rendering assets are incomplete or corrupt. Run npm run setup to repair them.",
+    );
   console.log(
     `Prepared ${Object.keys(entries).length} verified vanilla model/texture assets.`,
   );