feat: implement bff layer

lib/other-documents.ts

@@ -1,18 +1,14 @@
 /**
  * Data access layer for Other Documents.
  *
- * Uses dedicated Prisma models:
- *   - OtherDocumentMeta (collection: other_document_meta)
- *   - OtherDocumentChapter (collection: other_document_chapters)
- *
+ * Calls the BFF API for all data access (no direct Prisma usage).
  * Falls back to reading local JSON files from
- * lib/jsons/other-documents/<slug>/ when the database is unavailable.
+ * lib/jsons/other-documents/<slug>/ when the BFF is unavailable.
  *
  * Book codes are plain slugs (e.g. "analysis-bg", "real-peace-formula").
  */
 
-import { prisma } from "@/lib/db";
-import type { JsonValue } from "@prisma/client/runtime/library";
+import { bff, bffList } from "@/lib/bff";
 import fs from "fs";
 import path from "path";
 
@@ -72,6 +68,33 @@ export type OtherDocumentSidebarItem = {
   chapter: number;
 };
 
+// ---------------------------------------------------------------------------
+// BFF response types (snake_case from Go)
+// ---------------------------------------------------------------------------
+
+type BffDocumentMeta = {
+  id: string;
+  book: string;
+  data: {
+    title: string;
+    author: string;
+    year?: number | null;
+    description?: string | null;
+    totalChapters: number;
+    chapters: { number: number; title: string }[];
+  };
+};
+
+type BffChapter = {
+  id: string;
+  book: string;
+  chapter: number;
+  title: string;
+  type: string;
+  slug: string;
+  paragraphs: string[];
+};
+
 // ---------------------------------------------------------------------------
 // HTML sanitisation (same pattern used across all readers)
 // ---------------------------------------------------------------------------
@@ -90,23 +113,52 @@ function sanitizeHtml(html: string): string {
   return clean;
 }
 
-function normalizeParagraphs(paragraphs: string[] | JsonValue): string[] {
-  let result: string[];
+// ---------------------------------------------------------------------------
+// Mappers (BFF response → frontend types)
+// ---------------------------------------------------------------------------
 
-  if (typeof paragraphs === "string") {
-    try {
-      const parsed = JSON.parse(paragraphs);
-      result = Array.isArray(parsed) ? parsed : [paragraphs];
-    } catch {
-      result = [paragraphs];
-    }
-  } else if (Array.isArray(paragraphs)) {
-    result = paragraphs as string[];
-  } else {
-    result = [];
-  }
+function mapMetaData(raw: BffDocumentMeta): OtherDocumentMetaData {
+  const data =
+    raw.data && typeof raw.data === "object"
+      ? raw.data
+      : ({} as BffDocumentMeta["data"]);
+  return {
+    book: raw.book,
+    title: data.title ?? "",
+    author: data.author ?? "",
+    year: data.year ?? null,
+    description: data.description ?? null,
+    totalChapters: data.totalChapters ?? 0,
+    chapters: (data.chapters ?? []).map((ch) => ({
+      number: ch.number,
+      title: ch.title,
+    })),
+  };
+}
 
-  return result.map(sanitizeHtml);
+function mapSummary(raw: BffDocumentMeta): OtherDocumentSummary {
+  const data =
+    raw.data && typeof raw.data === "object"
+      ? raw.data
+      : ({} as BffDocumentMeta["data"]);
+  return {
+    book: raw.book,
+    title: data.title ?? "",
+    author: data.author ?? "",
+    year: data.year ?? null,
+    description: data.description ?? null,
+    totalChapters: data.totalChapters ?? 0,
+  };
+}
+
+function mapChapter(raw: BffChapter): OtherDocumentChapterData {
+  return {
+    book: raw.book,
+    chapter: raw.chapter,
+    title: raw.title,
+    type: raw.type,
+    paragraphs: (raw.paragraphs ?? []).map(sanitizeHtml),
+  };
 }
 
 // ---------------------------------------------------------------------------
@@ -195,22 +247,12 @@ function getLocalChapter(
  */
 export async function getAllOtherDocuments(): Promise<OtherDocumentSummary[]> {
   try {
-    const results = await prisma.otherDocumentMeta.findMany({
-      orderBy: { book: "asc" },
+    const results = await bffList<BffDocumentMeta>("/other-documents", {
+      tags: ["other-documents"],
     });
 
     if (results.length > 0) {
-      return results.map((row) => {
-        const data = row.data as unknown as OtherDocumentMetaData;
-        return {
-          book: row.book,
-          title: data.title,
-          author: data.author,
-          year: data.year ?? null,
-          description: data.description ?? null,
-          totalChapters: data.totalChapters,
-        };
-      });
+      return results.map(mapSummary);
     }
   } catch {
     // fall through to local JSON
@@ -234,12 +276,12 @@ export async function getOtherDocumentMeta(
   bookCode: string,
 ): Promise<OtherDocumentMetaData | null> {
   try {
-    const row = await prisma.otherDocumentMeta.findUnique({
-      where: { book: bookCode },
+    const raw = await bff<BffDocumentMeta>(`/other-documents/${bookCode}`, {
+      tags: [`other-doc-${bookCode}`],
     });
 
-    if (row) {
-      return row.data as unknown as OtherDocumentMetaData;
+    if (raw) {
+      return mapMetaData(raw);
     }
   } catch {
     // fall through to local JSON
@@ -258,23 +300,13 @@ export async function getOtherDocumentChapter(
   if (chapterNum < 1 || !Number.isInteger(chapterNum)) return null;
 
   try {
-    const doc = await prisma.otherDocumentChapter.findUnique({
-      where: {
-        book_slug: {
-          book: bookCode,
-          slug: String(chapterNum),
-        },
-      },
-    });
+    const raw = await bff<BffChapter>(
+      `/other-documents/${bookCode}/chapters/${chapterNum}`,
+      { tags: [`other-doc-${bookCode}`] },
+    );
 
-    if (doc) {
-      return {
-        book: doc.book,
-        chapter: doc.chapter,
-        title: doc.title,
-        type: doc.type,
-        paragraphs: normalizeParagraphs(doc.paragraphs),
-      };
+    if (raw) {
+      return mapChapter(raw);
     }
   } catch {
     // fall through to local JSON