'use server';

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

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

  const file = formData.get("file") as File;
  if (!file) throw new Error("No file selected");

  const accessToken = await getFreshAccessToken(session.user.id);
  const folderName = "WebCalibre";

  // --- 1. CHECK/CREATE THE WEBCALIBRE FOLDER ---
  // We check if the folder exists at the root of the user's OneDrive
  const folderCheckUrl = `https://graph.microsoft.com/v1.0/me/drive/root:/${folderName}`;
  const folderCheck = await fetch(folderCheckUrl, {
    headers: { Authorization: `Bearer ${accessToken}` }
  });

  if (folderCheck.status === 404) {
    console.log(`📂 Folder '${folderName}' not found. Creating it...`);
    const createFolderRes = await fetch(`https://graph.microsoft.com/v1.0/me/drive/root/children`, {
      method: "POST",
      headers: { 
        Authorization: `Bearer ${accessToken}`, 
        "Content-Type": "application/json" 
      },
      body: JSON.stringify({
        name: folderName,
        folder: {}, // Empty object tells Graph to create a folder
        "@microsoft.graph.conflictBehavior": "fail"
      })
    });
    
    if (!createFolderRes.ok) {
      const errorData = await createFolderRes.json();
      console.error("❌ Folder Creation Error:", errorData);
      throw new Error("Could not create WebCalibre folder on OneDrive.");
    }
  }

  // --- 2. CREATE UPLOAD SESSION ---
  // encodeURIComponent is vital for filenames with spaces or special characters
  const sessionUrl = `https://graph.microsoft.com/v1.0/me/drive/root:/${folderName}/${encodeURIComponent(file.name)}:/createUploadSession`;
  
  const sessionRes = await fetch(sessionUrl, {
    method: "POST",
    headers: { 
      Authorization: `Bearer ${accessToken}`, 
      "Content-Type": "application/json" 
    },
    body: JSON.stringify({ 
      item: { 
        "@microsoft.graph.conflictBehavior": "rename", // If file exists, name it "Book 1.pdf"
        name: file.name 
      } 
    })
  });

  const sessionData = await sessionRes.json();
  if (!sessionRes.ok) {
    console.error("❌ Session Error:", sessionData);
    throw new Error(sessionData.error?.message || "OneDrive session failed");
  }

  const { uploadUrl } = sessionData;

  // --- 3. UPLOAD THE DATA BYTES ---
  const buffer = Buffer.from(await file.arrayBuffer());
  const uploadRes = await fetch(uploadUrl, {
    method: "PUT",
    headers: { 
      "Content-Length": `${file.size}`,
      "Content-Range": `bytes 0-${file.size - 1}/${file.size}` 
    },
    body: buffer
  });

  if (!uploadRes.ok) {
    const uploadError = await uploadRes.json();
    console.error("❌ Upload Error:", uploadError);
    throw new Error("Chunk upload failed");
  }
  
  const driveItem = await uploadRes.json();

  // --- 4. RECORD IN POSTGRESQL (PRISMA) ---
  await prisma.fileNode.create({
    data: {
      oneDriveId: driveItem.id,
      name: file.name,
      size: BigInt(file.size),
      isFolder: false,
      path: `/${folderName}/${file.name}`,
      ownerId: session.user.id,
      metadata: { 
        type: file.name.split('.').pop()?.toUpperCase() || "UNKNOWN",
        mimeType: file.type 
      }
    }
  });

  // Revalidate ensures the dashboard list updates immediately
  revalidatePath("/dashboard");
  
  return { success: true };
}