import { getServerSession } from "next-auth/next";
import { authOptions } from "@/app/api/auth/[...nextauth]/route";
import { NextResponse } from "next/server";

interface Task {
  id: string;
  headline: string;
  projectName: string;
  status: string;
  dueDate: string | null;
  details?: string;
  milestone?: string;
}

// Cache for user IDs
const userCache = new Map<string, number>();

export async function GET() {
  const session = await getServerSession(authOptions);

  if (!session || !session.user?.email) {
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
  }

  try {
    console.log('Fetching tasks for user:', session.user.id);
    console.log('Using LEANTIME_TOKEN:', process.env.LEANTIME_TOKEN ? 'Present' : 'Missing');

    // Check cache first
    let leantimeUserId = userCache.get(session.user.email);
    
    // If not in cache, fetch from API
    if (!leantimeUserId) {
      const userResponse = await fetch('https://agilite.slm-lab.net/api/jsonrpc', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
          'X-API-Key': process.env.LEANTIME_TOKEN || '',
        },
        body: JSON.stringify({
          method: 'leantime.rpc.Users.Users.getUserByEmail',
          jsonrpc: '2.0',
          id: 1,
          params: {
            email: session.user.email
          }
        })
      });

      if (!userResponse.ok) {
        const errorData = await userResponse.json();
        console.error('User lookup failed:', errorData);
        if (userResponse.status === 429) {
          const retryAfter = userResponse.headers.get('retry-after') || '60';
          return NextResponse.json(
            { error: "Rate limit exceeded. Please try again later." },
            { 
              status: 429,
              headers: {
                'Retry-After': retryAfter
              }
            }
          );
        }
        throw new Error('Failed to fetch user data from Leantime');
      }

      const userData = await userResponse.json();
      console.log('User lookup response:', userData);

      if (!userData.result || !userData.result.id) {
        throw new Error('Could not find Leantime user ID');
      }

      leantimeUserId = userData.result.id as number;
      // Cache the user ID for 5 minutes
      if (session.user.email) {
        userCache.set(session.user.email, leantimeUserId);
        setTimeout(() => userCache.delete(session.user.email!), 5 * 60 * 1000);
      }
    }

    // Fetch all tasks assigned to the user
    const response = await fetch('https://agilite.slm-lab.net/api/jsonrpc', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'X-API-Key': process.env.LEANTIME_TOKEN || '',
      },
      body: JSON.stringify({
        jsonrpc: '2.0',
        method: 'leantime.rpc.Tickets.Tickets.getAllStatusLabelsByUserId',
        id: 1,
        params: {
          userId: leantimeUserId
        }
      })
    });

    if (!response.ok) {
      const errorData = await response.json();
      console.error('Tasks fetch failed:', errorData);
      throw new Error(`Failed to fetch tasks: ${errorData.error || 'Unknown error'}`);
    }

    const data = await response.json();
    console.log('Tasks response:', data);
    
    if (!data.result) {
      return NextResponse.json({ tasks: [] });
    }

    // Get project details to include project names
    const projectsResponse = await fetch('https://agilite.slm-lab.net/api/jsonrpc', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'X-API-Key': process.env.LEANTIME_TOKEN || '',
      },
      body: JSON.stringify({
        jsonrpc: '2.0',
        method: 'leantime.rpc.Projects.getAll',
        id: 1
      })
    });

    if (!projectsResponse.ok) {
      throw new Error('Failed to fetch projects');
    }

    const projectsData = await projectsResponse.json();
    const projectsMap = new Map(
      projectsData.result.map((project: any) => [project.id, project.name])
    );

    // Transform and categorize the tasks
    const tasks = data.result.map((task: any) => {
      const dueDate = task.dateToFinish ? new Date(task.dateToFinish * 1000) : null;
      
      return {
        id: task.id,
        headline: task.headline,
        projectName: projectsMap.get(task.projectId) || `Project ${task.projectId}`,
        status: task.status,
        dueDate: dueDate ? dueDate.toISOString() : null,
        details: task.description,
        milestone: task.milestoneName
      };
    });

    // Sort tasks by due date
    tasks.sort((a: Task, b: Task) => {
      if (!a.dueDate && !b.dueDate) return 0;
      if (!a.dueDate) return 1;
      if (!b.dueDate) return -1;
      return new Date(a.dueDate).getTime() - new Date(b.dueDate).getTime();
    });

    return NextResponse.json({ tasks });
  } catch (error) {
    console.error('Error fetching tasks:', error);
    return NextResponse.json(
      { error: error instanceof Error ? error.message : "Failed to fetch tasks" },
      { status: 500 }
    );
  }
}