Start provider onboarding for a seller

import type { MedusaContainer } from "@medusajs/framework/types"
import { ContainerRegistrationKeys } from "@medusajs/framework/utils"

export async function getPayoutAccountId(
  container: MedusaContainer,
  sellerId: string
) {
  const query = container.resolve(ContainerRegistrationKeys.QUERY)
  const { data: [seller] } = await query.graph({
    entity: "seller",
    fields: ["payout_account.id"],
    filters: { id: sellerId },
  })
  return seller?.payout_account?.id as string | undefined
}

import type { MedusaRequest, MedusaResponse } from "@medusajs/framework/http"
import { MedusaError } from "@medusajs/framework/utils"
import { createOnboardingWorkflow } from "@mercurjs/core/workflows"
import { getPayoutAccountId } from "./helpers"

export async function POST(req: MedusaRequest, res: MedusaResponse) {
  const accountId = await getPayoutAccountId(req.scope, req.params.id)
  if (!accountId) {
    throw new MedusaError(MedusaError.Types.NOT_FOUND, "No payout account")
  }

  const { result } = await createOnboardingWorkflow(req.scope).run({
    input: {
      account_id: accountId,
      data: {
        refresh_url: "https://vendor.example.com/payouts/refresh",
        return_url: "https://vendor.example.com/payouts",
      },
    },
  })

  res.json({ url: result.data?.url })
}