Module Update

src/modules/questions/actions.ts

@@ -0,0 +1,140 @@
+"use server";
+
+import { db } from "@/shared/db";
+import { questions, questionsToKnowledgePoints } from "@/shared/db/schema";
+import { CreateQuestionInput, CreateQuestionSchema } from "./schema";
+import { ActionState } from "@/shared/types/action-state";
+import { revalidatePath } from "next/cache";
+import { ZodError } from "zod";
+import { eq } from "drizzle-orm";
+import { createId } from "@paralleldrive/cuid2";
+
+// --- Mock Auth Helper (Replace with actual Auth.js call) ---
+async function getCurrentUser() {
+  // In production: const session = await auth(); return session?.user;
+  // Mocking a teacher user for this demonstration
+  return {
+    id: "user_teacher_123",
+    role: "teacher", // or "admin"
+  };
+}
+
+async function ensureTeacher() {
+  const user = await getCurrentUser();
+  if (!user || (user.role !== "teacher" && user.role !== "admin")) {
+    throw new Error("Unauthorized: Only teachers can perform this action.");
+  }
+  return user;
+}
+
+// --- Recursive Insert Helper ---
+// We pass 'tx' to ensure all operations run within the same transaction
+async function insertQuestionWithRelations(
+  tx: any, // using any or strict Drizzle Transaction type if imported
+  input: CreateQuestionInput,
+  authorId: string,
+  parentId: string | null = null
+) {
+  // We generate ID explicitly here.
+  const newQuestionId = createId();
+
+  await tx.insert(questions).values({
+    id: newQuestionId,
+    content: input.content,
+    type: input.type,
+    difficulty: input.difficulty,
+    authorId: authorId,
+    parentId: parentId,
+  });
+
+  // 2. Link Knowledge Points
+  if (input.knowledgePointIds && input.knowledgePointIds.length > 0) {
+    await tx.insert(questionsToKnowledgePoints).values(
+      input.knowledgePointIds.map((kpId) => ({
+        questionId: newQuestionId,
+        knowledgePointId: kpId,
+      }))
+    );
+  }
+
+  // 3. Handle Sub-Questions (Recursion)
+  if (input.subQuestions && input.subQuestions.length > 0) {
+    for (const subQ of input.subQuestions) {
+      await insertQuestionWithRelations(tx, subQ, authorId, newQuestionId);
+    }
+  }
+
+  return newQuestionId;
+}
+
+// --- Main Server Action ---
+
+export async function createNestedQuestion(
+  prevState: ActionState<string> | undefined,
+  formData: FormData | CreateQuestionInput // Support both FormData and JSON input
+): Promise<ActionState<string>> {
+  try {
+    // 1. Auth Check
+    const user = await ensureTeacher();
+
+    // 2. Parse Input
+    // If formData is actual FormData, we need to convert it. 
+    // For complex nested structures, frontend usually sends JSON string or pure JSON object if using `useServerAction` with arguments.
+    // Here we assume the client might send a raw object (if using direct function call) or we parse FormData.
+    let rawInput: any = formData;
+    
+    if (formData instanceof FormData) {
+       // Parsing complex nested JSON from FormData is messy. 
+       // We assume one field 'data' contains the JSON, or we expect direct object usage (common in modern Next.js RPC).
+       const jsonString = formData.get("json");
+       if (typeof jsonString === "string") {
+         rawInput = JSON.parse(jsonString);
+       } else {
+         return { success: false, message: "Invalid submission format. Expected JSON." };
+       }
+    }
+
+    const validatedFields = CreateQuestionSchema.safeParse(rawInput);
+
+    if (!validatedFields.success) {
+      return {
+        success: false,
+        message: "Validation failed",
+        errors: validatedFields.error.flatten().fieldErrors,
+      };
+    }
+
+    const input = validatedFields.data;
+
+    // 3. Database Transaction
+    await db.transaction(async (tx) => {
+      await insertQuestionWithRelations(tx, input, user.id, null);
+    });
+
+    // 4. Revalidate Cache
+    revalidatePath("/questions");
+
+    return {
+      success: true,
+      message: "Question created successfully",
+    };
+
+  } catch (error) {
+    console.error("Failed to create question:", error);
+
+    // Drizzle/DB Error Handling (Generic)
+    if (error instanceof Error) {
+       // Check for specific DB errors (constraints, etc.)
+       // e.g., if (error.message.includes("Duplicate entry")) ...
+       return {
+         success: false,
+         message: error.message || "Database error occurred",
+       };
+    }
+
+    return {
+      success: false,
+      message: "An unexpected error occurred",
+    };
+  }
+}