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

// Global cache reference (will be moved to a proper cache solution in the future)
declare global {
  var emailListCache: { [key: string]: { data: any, timestamp: number } };
}

// Helper function to invalidate cache for a specific folder
const invalidateCache = (userId: string, folder?: string) => {
  if (!global.emailListCache) return;
  
  Object.keys(global.emailListCache).forEach(key => {
    // If folder is provided, only invalidate that folder's cache
    if (folder) {
      if (key.includes(`${userId}:${folder}`)) {
        delete global.emailListCache[key];
      }
    } else {
      // Otherwise invalidate all user's caches
      if (key.startsWith(`${userId}:`)) {
        delete global.emailListCache[key];
      }
    }
  });
};

// Mark email as read
export async function POST(
  request: Request,
  context: { params: { id: string } }
) {
  try {
    const session = await getServerSession(authOptions);
    if (!session || !session.user?.id) {
      return NextResponse.json(
        { error: "Not authenticated" },
        { status: 401 }
      );
    }

    // Await params as per Next.js requirements
    const params = await context.params;
    const id = params?.id;
    if (!id) {
      return NextResponse.json(
        { error: "Missing email ID" },
        { status: 400 }
      );
    }

    const { isRead, folder, accountId } = await request.json();
    
    if (typeof isRead !== 'boolean') {
      return NextResponse.json(
        { error: "Invalid 'isRead' parameter. Must be a boolean." },
        { status: 400 }
      );
    }

    const normalizedFolder = folder || "INBOX";
    const effectiveAccountId = accountId || 'default';

    // Use the email service to mark the email
    const success = await markEmailReadStatus(
      session.user.id,
      id,
      isRead,
      normalizedFolder,
      effectiveAccountId
    );

    if (!success) {
      return NextResponse.json(
        { error: `Failed to ${isRead ? 'mark email as read' : 'mark email as unread'}` },
        { status: 500 }
      );
    }

    // Invalidate cache for this email
    await invalidateEmailContentCache(session.user.id, effectiveAccountId, id);
    
    // Also invalidate folder cache to update unread counts
    await invalidateFolderCache(session.user.id, effectiveAccountId, normalizedFolder);
    
    return NextResponse.json({ success: true });
  } catch (error: any) {
    console.error("Error in mark-read API:", error);
    return NextResponse.json(
      { error: "Internal server error", message: error.message },
      { status: 500 }
    );
  }
}