// The CRDT write. A client produces an encoded update from its local
// `crdtText()` handle (`handle.encode()`) and sends it here. The server does
// NOT overwrite `body` with it — the runtime folds the incoming update into the
// STORED state with `mergeCrdtStates` on the write path (see the `.server.ts`
// comment), so two clients that edited the same base CONVERGE. `update` is the
// opaque encoded CRDT state/delta (`bytes`); the same wire shape a Yjs update
// blob carries.
//
// `op: 'update'` targets the existing row by its primary key. There is no
// tenant field in the input: the `tenant()` mixin auto-scopes the update to the
// caller's tenant, so a foreign `id` simply matches no row.

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

export const setDocumentBody = defineMutation({
  name: 'documents.setBody',
  target: { table: 'documents', op: 'update' },
  // Open, and note WHAT the CRDT changes about the risk: the server does not
  // overwrite `body` with the caller's bytes, it MERGES them
  // (`mergeCrdtStates`), so a concurrent editor's text is not destroyed by a
  // conflicting write — the two converge. `tenant()` scopes the update, so an
  // id from another tenant matches no row at all.
  //
  // What remains open is who may join an editing session, and that needs an
  // identity this template does not ship: with no auth strategy every caller is
  // an anonymous Subject holding no scopes, so a `guards:` would deny everyone.
  openAccess:
    'merges a caller-supplied CRDT update into a document of the request\'s tenant — a merge, '
    + 'not an overwrite, so no concurrent editor\'s text is lost, and an id outside the tenant '
    + 'matches no row. Guard who may edit once the app has an identity.',
  input: Schema.Struct({
    id: Schema.NonEmptyString,
    update: Schema.Uint8ArrayFromBase64,
  }),
  output: Schema.Struct({
    id: Schema.String,
    title: Schema.String,
    // The MERGED body — what every subscriber now converges to.
    body: Schema.NullOr(Schema.Uint8ArrayFromBase64),
    tenantId: Schema.String,
  }),
})