Automation that runs
under real load.

import { workflow, step, humanTask, ai } from "@apollo/workflow"
import { z } from "zod"

// Step-based execution. Every step is independently retryable.
// The audit trail is generated by the engine, not by hand.

const InvoiceInput = z.object({
  documentId: z.string(),
  vendorId: z.string(),
});

export const processInvoice = workflow(
  { name: "process-invoice", input: InvoiceInput },
  async ({ documentId, vendorId }) => {
    // 1. Extract structured data with AI. Records model + version.
    const extracted = await step("extract", async () => {
      return await ai.extract({
        document: documentId,
        schema: InvoiceSchema,
      });
    });

    // 2. Validate against business rules. Returns a confidence score.
    const validation = await step("validate", () => {
      return validateInvoice(extracted, { vendorId });
    });

    // 3. Human review whenever the rules can't decide on their own.
    if (validation.confidence < 0.95) {
      const review = await humanTask("invoice-review", {
        queue: "ap-team",
        extracted,
        validation,
        slaMinutes: 240,
      });

      if (!review.approved) {
        return { status: "rejected", reason: review.reason };
      }
    }

    // 4. Write to ERP. Idempotent on the workflow run id.
    return await step("post-to-erp", async () => {
      return await erp.invoice.create(extracted);
    });
  },
);