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';

// 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") || "";
    
    // Check cache - temporary until we implement a proper server-side cache
    const cacheKey = `${session.user.id}:${folder}:${page}:${perPage}:${searchQuery}`;
    const now = Date.now();
    const cachedEmails = emailListCache[cacheKey];

    if (cachedEmails && now - cachedEmails.timestamp < CACHE_TTL) {
      console.log(`Using cached emails for ${cacheKey}`);
      return NextResponse.json(cachedEmails.data);
    }

    console.log(`Cache miss for ${cacheKey}, fetching emails`);

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

    // Cache the results
    emailListCache[cacheKey] = {
      data: emailsResult,
      timestamp: now
    };

    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 cache entries for this folder or all folders if none specified
    const userId = session.user.id;
    Object.keys(emailListCache).forEach(key => {
      if (folderName) {
        if (key.includes(`${userId}:${folderName}`)) {
          delete emailListCache[key];
        }
      } else {
        if (key.startsWith(`${userId}:`)) {
          delete emailListCache[key];
        }
      }
    });
    
    return NextResponse.json({ success: true });
  } catch (error) {
    console.error('Error in POST handler:', error);
    return NextResponse.json({ error: 'An unexpected error occurred' }, { status: 500 });
  }
}