// Time-travel: the document's value as of a past instant (`at`, epoch ms).
// Returns null if it didn't exist (or was deleted) then.

import { defineAction } from '@voltro/protocol'
import { Schema } from 'effect'

export const documentAsOf = defineAction({
  name: 'documents.asOf',
  // Open, with the same load-bearing detail as `documents.history`: the
  // executor passes `ctx.request.subject.tenantId` into `rowAsOf` explicitly,
  // because a version table is not auto-scoped by the `tenant()` mixin. That
  // argument is what keeps a caller-supplied id from reading another tenant's
  // past values; do not drop it.
  //
  // No auth strategy and no rbac ship in this template, so a scope guard would
  // deny every caller rather than the wrong ones.
  openAccess:
    'returns one past value of a document in the CALLER\'S OWN tenant — `rowAsOf` is passed '
    + '`subject.tenantId` explicitly, so an id from another tenant returns null. Time travel '
    + 'reaches only where the live read already could.',
  input: Schema.Struct({ id: Schema.String, at: Schema.Number }),
  output: Schema.NullOr(Schema.Struct({
    title: Schema.String,
    content: Schema.String,
  })),
})