import { NextResponse } from 'next/server';
import { getServerSession } from 'next-auth';
import { authOptions } from '@/app/api/auth/[...nextauth]/route';
import { getEmails } from '@/lib/services/email-service';
import { 
  getCachedEmailList, 
  cacheEmailList, 
  invalidateFolderCache 
} from '@/lib/redis';

// Simple in-memory cache (will be removed in a future update)
interface EmailCacheEntry {
  data: any;
  timestamp: number;
}

// Cache for 1 minute only
const CACHE_TTL = 60 * 1000;
const emailListCache: Record<string, EmailCacheEntry> = {};

export async function GET(request: Request) {
  try {
    // Authenticate user
    const session = await getServerSession(authOptions);
    if (!session || !session.user?.id) {
      return NextResponse.json(
        { error: "Not authenticated" },
        { status: 401 }
      );
    }

    // Extract query parameters
    const { searchParams } = new URL(request.url);
    const page = parseInt(searchParams.get("page") || "1");
    const perPage = parseInt(searchParams.get("perPage") || "20");
    const folder = searchParams.get("folder") || "INBOX";
    const searchQuery = searchParams.get("search") || "";
    const accountId = searchParams.get("accountId") || "";
    
    // Try to get from Redis cache first, but only if it's not a search query
    if (!searchQuery) {
      const cacheKey = accountId ? `${session.user.id}:${accountId}:${folder}` : `${session.user.id}:${folder}`;
      const cachedEmails = await getCachedEmailList(session.user.id, folder, page, perPage);
      if (cachedEmails) {
        console.log(`Using Redis cached emails for ${cacheKey}:${page}:${perPage}`);
        return NextResponse.json(cachedEmails);
      }
    }

    console.log(`Redis cache miss for ${session.user.id}:${folder}:${page}:${perPage}, fetching emails from IMAP`);

    // Use the email service to fetch emails, passing the accountId if provided
    const emailsResult = await getEmails(
      session.user.id,
      folder,
      page,
      perPage,
      searchQuery,
      accountId
    );

    // The result is already cached in the getEmails function
    return NextResponse.json(emailsResult);
  } catch (error: any) {
    console.error("Error fetching emails:", error);
    return NextResponse.json(
      { error: "Failed to fetch emails", message: error.message },
      { status: 500 }
    );
  }
}

export async function POST(request: Request) {
  try {
    const session = await getServerSession(authOptions);
    if (!session?.user?.id) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
    }
    
    const { emailId, folderName } = await request.json();
    
    if (!emailId) {
      return NextResponse.json({ error: 'Missing emailId parameter' }, { status: 400 });
    }
    
    // Invalidate Redis cache for the folder
    if (folderName) {
      await invalidateFolderCache(session.user.id, folderName);
    } else {
      // If no folder specified, invalidate all folders (using a wildcard pattern)
      const folders = ['INBOX', 'Sent', 'Drafts', 'Trash', 'Junk'];
      for (const folder of folders) {
        await invalidateFolderCache(session.user.id, folder);
      }
    }
    
    return NextResponse.json({ success: true });
  } catch (error) {
    console.error('Error in POST handler:', error);
    return NextResponse.json({ error: 'An unexpected error occurred' }, { status: 500 });
  }
}