web-next: View and request article translations

graphql/post.ts

@@ -6,7 +6,9 @@ import { getAvatarUrl } from "@hackerspub/models/account";
 import {
   createArticle,
   deleteArticleDraft,
+  getOriginalArticleContent,
   LanguageChangeWithTranslationsError,
+  startArticleContentTranslation,
   updateArticle,
   updateArticleDraft,
 } from "@hackerspub/models/article";
@@ -17,7 +19,7 @@ import {
 } from "@hackerspub/models/bookmark";
 import { isReactionEmoji, renderCustomEmojis } from "@hackerspub/models/emoji";
 import { addExternalLinkTargets, stripHtml } from "@hackerspub/models/html";
-import { negotiateLocale } from "@hackerspub/models/i18n";
+import { negotiateLocale, normalizeLocale } from "@hackerspub/models/i18n";
 import { renderMarkup } from "@hackerspub/models/markup";
 import { createNote } from "@hackerspub/models/note";
 import {
@@ -65,17 +67,39 @@ class SharedPostDeletionNotAllowedError extends Error {
   }
 }
 
+type LlmTranslationNotAllowedReason = "DISABLED" | "SAME_LANGUAGE";
+
+class LlmTranslationNotAllowedError extends Error {
+  public constructor(public readonly reason: LlmTranslationNotAllowedReason) {
+    super(`LLM translation not allowed: ${reason}`);
+  }
+}
+
 export const PostType = builder.enumType("PostType", {
   values: ["ARTICLE", "NOTE", "QUESTION"],
 });
 
+const LlmTranslationNotAllowedReasonRef = builder.enumType(
+  "LlmTranslationNotAllowedReason",
+  {
+    values: ["DISABLED", "SAME_LANGUAGE"] as const,
+  },
+);
+
 builder.objectType(SharedPostDeletionNotAllowedError, {
   name: "SharedPostDeletionNotAllowedError",
   fields: (t) => ({
     inputPath: t.expose("inputPath", { type: "String" }),
   }),
 });
 
+builder.objectType(LlmTranslationNotAllowedError, {
+  name: "LlmTranslationNotAllowedError",
+  fields: (t) => ({
+    reason: t.expose("reason", { type: LlmTranslationNotAllowedReasonRef }),
+  }),
+});
+
 export const Post = builder.drizzleInterface("postTable", {
   variant: "Post",
   interfaces: [Reactable, Node],
@@ -301,11 +325,9 @@ export const Article = builder.drizzleNode("postTable", {
         with: {
           articleSource: {
             with: {
-              contents: {
-                where: {
-                  beingTranslated: args.includeBeingTranslated ?? false,
-                },
-              },
+              contents: args.includeBeingTranslated
+                ? {}
+                : { where: { beingTranslated: false } },
             },
           },
         },
@@ -1775,6 +1797,104 @@ builder.relayMutationField(
   },
 );
 
+builder.relayMutationField(
+  "requestArticleTranslation",
+  {
+    inputFields: (t) => ({
+      articleId: t.globalID({ for: [Article], required: true }),
+      targetLanguage: t.field({ type: "Locale", required: true }),
+    }),
+  },
+  {
+    errors: {
+      types: [
+        NotAuthenticatedError,
+        InvalidInputError,
+        LlmTranslationNotAllowedError,
+      ],
+    },
+    async resolve(_root, args, ctx) {
+      const session = await ctx.session;
+      if (session == null || ctx.account == null) {
+        throw new NotAuthenticatedError();
+      }
+
+      const post = await ctx.db.query.postTable.findFirst({
+        where: { id: args.input.articleId.id },
+        with: {
+          actor: {
+            with: {
+              followers: true,
+              blockees: true,
+              blockers: true,
+            },
+          },
+          mentions: true,
+          articleSource: {
+            with: { contents: true },
+          },
+        },
+      });
+      if (
+        post == null ||
+        post.type !== "Article" ||
+        post.articleSource == null ||
+        !isPostVisibleTo(post, ctx.account.actor)
+      ) {
+        throw new InvalidInputError("articleId");
+      }
+      if (!post.articleSource.allowLlmTranslation) {
+        throw new LlmTranslationNotAllowedError("DISABLED");
+      }
+      const original = getOriginalArticleContent(post.articleSource);
+      if (original == null) {
+        throw new InvalidInputError("articleId");
+      }
+      // The `Locale` scalar accepts any syntactically valid BCP 47
+      // tag, but the `[lang]` route only serves locales that pass
+      // `normalizeLocale` (i.e. the `POSSIBLE_LOCALES` whitelist
+      // used across the project).  Run the same check here so an
+      // API client cannot enqueue a translation for a tag the
+      // canonical article URL flow will never display.
+      const targetLanguage = normalizeLocale(
+        args.input.targetLanguage.baseName,
+      );
+      if (targetLanguage == null) {
+        throw new InvalidInputError("targetLanguage");
+      }
+      // Reject not just exact matches (`en` -> `en`) but also any
+      // request whose target shares the source's BCP 47 language
+      // subtag (`en` -> `en-US`, `ko` -> `ko-KR`).  `Article.contents`
+      // negotiates among available locales rather than requiring an
+      // exact tag, so allowing a same-language variant would create
+      // a redundant placeholder row whose canonical URL would
+      // negotiate back to the existing source content and leave the
+      // newly inserted row unreachable.
+      const targetSubtag = new Intl.Locale(targetLanguage).language;
+      const originalSubtag = new Intl.Locale(original.language).language;
+      if (targetSubtag === originalSubtag) {
+        throw new LlmTranslationNotAllowedError("SAME_LANGUAGE");
+      }
+
+      await startArticleContentTranslation(ctx.fedCtx, {
+        content: original,
+        targetLanguage,
+        requester: ctx.account,
+      });
+
+      return post;
+    },
+  },
+  {
+    outputFields: (t) => ({
+      article: t.field({
+        type: Article,
+        resolve: (post) => post,
+      }),
+    }),
+  },
+);
+
 interface UploadMediaResult {
   url: string;
   width: number;

graphql/schema.graphql

@@ -647,6 +647,15 @@ The `JSON` scalar type represents JSON values as specified by [ECMA-404](http://
 """
 scalar JSON
 
+type LlmTranslationNotAllowedError {
+  reason: LlmTranslationNotAllowedReason!
+}
+
+enum LlmTranslationNotAllowedReason {
+  DISABLED
+  SAME_LANGUAGE
+}
+
 """A BCP 47-compliant language tag."""
 scalar Locale
 
@@ -766,6 +775,7 @@ type Mutation {
   registerFcmDeviceToken(input: RegisterFcmDeviceTokenInput!): RegisterFcmDeviceTokenResult!
   removeFollower(input: RemoveFollowerInput!): RemoveFollowerResult!
   removeReactionFromPost(input: RemoveReactionFromPostInput!): RemoveReactionFromPostResult!
+  requestArticleTranslation(input: RequestArticleTranslationInput!): RequestArticleTranslationResult!
   revokePasskey(passkeyId: ID!): ID
 
   """Revoke a session by its ID."""
@@ -1426,6 +1436,19 @@ type ReplyNotification implements Node & Notification {
   uuid: UUID!
 }
 
+input RequestArticleTranslationInput {
+  articleId: ID!
+  clientMutationId: ID
+  targetLanguage: Locale!
+}
+
+type RequestArticleTranslationPayload {
+  article: Article!
+  clientMutationId: ID
+}
+
+union RequestArticleTranslationResult = InvalidInputError | LlmTranslationNotAllowedError | NotAuthenticatedError | RequestArticleTranslationPayload
+
 input SaveArticleDraftInput {
   clientMutationId: ID
   content: Markdown!