'use server';

import { auth } from "@/auth";
import { prisma } from "@/lib/prisma";
import { revalidatePath } from "next/cache";
import { getFreshAccessToken } from "@/lib/auth-utils";

export async function syncOneDrive() {
  const session = await auth();
  
  if (!session?.user?.id) throw new Error("Unauthorized");

  try {
    const accessToken = await getFreshAccessToken(session.user.id);

    if (!accessToken) {
      throw new Error("Microsoft account not linked properly or session expired.");
    }

    const response = await fetch("https://graph.microsoft.com/v1.0/me/drive/root:/WebCalibre:/children", {
      headers: { 
        Authorization: `Bearer ${accessToken}`,
        "Content-Type": "application/json"
      },
    });
    
    if (!response.ok) {
      const errorData = await response.json();
      if (response.status === 404) {
        return { success: true, count: 0 };
      }
      throw new Error(errorData.error?.message || "Failed to fetch data from OneDrive");
    }

    const data = await response.json();
    let syncedCount = 0;

    // Regular expression to identify if a string is a UUID
    const uuidRegex = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i;

    for (const item of data.value) {
      const isFolder = !!item.folder;

      /**
       * FILTER: If the item is a folder and the name is a UUID, skip it.
       * These are storage containers created by the upload action, not user-facing folders.
       */
      if (isFolder && uuidRegex.test(item.name)) {
        continue;
      }

      const extension = isFolder 
        ? 'FOLDER' 
        : (item.name.split('.').pop()?.toUpperCase() || 'UNKNOWN');

      const fileSize = item.size ? BigInt(item.size) : BigInt(0);

      await prisma.fileNode.upsert({
        where: { oneDriveId: item.id },
        update: {
          name: item.name,
          size: fileSize,
          isFolder: isFolder,
          metadata: { 
            type: extension,
            mimeType: item.file?.mimeType || null 
          },
          path: item.parentReference?.path + '/' + item.name,
          updatedAt: new Date(),
        },
        create: {
          id: crypto.randomUUID(), 
          oneDriveId: item.id,
          name: item.name,
          size: fileSize,
          isFolder: isFolder,
          path: item.parentReference?.path + '/' + item.name,
          ownerId: session.user.id,
          metadata: { 
            type: extension,
            mimeType: item.file?.mimeType || null 
          },
        }
      });
      syncedCount++;
    }
    
    revalidatePath('/dashboard');
    return { success: true, count: syncedCount };

  } catch (error: any) {
    console.error("Sync Process Failure:", error.message);
    throw new Error(error.message || "An unexpected error occurred during sync.");
  }
}