fix(po-pdf): capture PB token on upload and route GET through proxy

src/app/api/v1/purchase-orders/[id]/pdf/route.ts

@@ -212,29 +212,32 @@ export async function POST(
     // PB file fields accept an array of File/Blob. Append to the
     // existing array so every regen is preserved (operator can scroll
     // through documents_history to find v1, v2, v3...).
-    const newHistoryEntry: PurchaseOrderDocumentEntry = {
-      version: nextVersion,
-      file: filename,
-      // Task 2 will swap this for the real PB token returned from
-      // the upload response. For now we persist an empty string so
-      // the schema compiles; the GET handler falls back to
-      // `documents[idx]` when token is empty (legacy rows).
-      token: "",
-      generatedAt: generatedAtIso,
-      generatedBy: body.generatedBy || "",
-      reason: (body.notes || "").slice(0, 500),
-      status: "current",
-    };
-
     const formData = new FormData();
     formData.append(
       "documents",
       new Blob([new Uint8Array(pdfBuffer)], { type: "application/pdf" }),
       filename
     );
-    // PB SDK FormData update only accepts the file — append the history
-    // via a second update call (it's JSON, not a file).
-    await pb.collection("purchase_orders").update(poId, formData);
+    // PB returns the stored file tokens (slugged) in the response.
+    // We need the actual on-disk token for later fetches, not the
+    // human-readable `filename` we sent. Append to the existing array
+    // and pick the last element.
+    const updated = await pb.collection("purchase_orders").update<{
+      documents: string[] | string;
+    }>(poId, formData);
+    const docsRaw = updated?.documents ?? [];
+    const docs = Array.isArray(docsRaw) ? docsRaw : [docsRaw];
+    const newToken = docs[docs.length - 1] ?? "";
+
+    const newHistoryEntry: PurchaseOrderDocumentEntry = {
+      version: nextVersion,
+      file: filename,
+      token: newToken,
+      generatedAt: generatedAtIso,
+      generatedBy: body.generatedBy || "",
+      reason: (body.notes || "").slice(0, 500),
+      status: "current",
+    };
 
     // Append the new history entry. PB handles the array merge via
     // JSON Patch — actually no, with plain PATCH we'd replace the
@@ -316,7 +319,9 @@ export async function GET(
       const v = parseInt(versionParam, 10);
       entry = history.find((h) => h.version === v);
     } else {
-      entry = history.find((h) => h.status === "current") ?? history[history.length - 1];
+      entry =
+        history.find((h) => h.status === "current") ??
+        history[history.length - 1];
     }
 
     if (!entry) {
@@ -326,21 +331,48 @@ export async function GET(
       );
     }
 
-    const fileUrl = pb.files.getURL(
-      { collectionId: "purchase_orders", id: poId },
-      entry.file,
-    );
-    const fileRes = await fetch(fileUrl, {
-      headers: { Authorization: pb.authStore.token ?? "" },
-    });
-    if (!fileRes.ok) {
+    // Resolve a token. Newer rows have `entry.token` (PB-stored slug).
+    // Legacy rows may have only `entry.file` (the human-readable name).
+    // For legacy rows, fall back to the live `documents` array — the
+    // POST handler always appends to both arrays in sync, so index
+    // alignment gives us the right token.
+    let token = entry.token;
+    if (!token) {
+      const docsRaw = po.documents ?? [];
+      const docs = Array.isArray(docsRaw) ? docsRaw : [docsRaw];
+      const idx = history.findIndex((h) => h.version === entry!.version);
+      token = docs[idx] || docs[0] || "";
+    }
+
+    if (!token) {
       return NextResponse.json(
-        { error: `Upstream PB file fetch failed: ${fileRes.status}` },
-        { status: 502 }
+        {
+          error: `PDF token missing for version ${entry.version} — please regenerate.`,
+        },
+        { status: 404 }
       );
     }
-    const buf = Buffer.from(await fileRes.arrayBuffer());
 
+    // Hand off to the existing file proxy. The proxy already has
+    // `purchase_orders` whitelisted and streams the bytes back with
+    // admin auth.
+    const proxyUrl = `/api/v1/files/purchase_orders/${poId}/${encodeURIComponent(token)}`;
+    const proxyRes = await fetch(
+      new URL(proxyUrl, req.nextUrl.origin).toString(),
+      {
+        headers: { cookie: req.headers.get("cookie") ?? "" },
+      }
+    );
+
+    if (!proxyRes.ok) {
+      const body = await proxyRes.json().catch(() => ({}));
+      return NextResponse.json(
+        { error: body?.error || `Proxy fetch failed: ${proxyRes.status}` },
+        { status: proxyRes.status === 404 ? 404 : 502 }
+      );
+    }
+
+    const buf = Buffer.from(await proxyRes.arrayBuffer());
     const safePo = String(po.po_number || poId).replace(/[^\w.-]/g, "_");
     const filename = `PO-v${entry.version}-${safePo}.pdf`;