import { NextRequest, NextResponse } from "next/server";
import { getServerSession } from "next-auth/next";
import { authOptions } from "@/app/api/auth/options";
import { getCachedTasksData, cacheTasksData } from "@/lib/redis";
import { logger } from "@/lib/logger";

interface Task {
  id: string;
  headline: string;
  projectName: string;
  projectId: number;
  status: number;
  dateToFinish: string | null;
  milestone: string | null;
  details: string | null;
  createdOn: string;
  editedOn: string | null;
  editorId: string;
  editorFirstname: string;
  editorLastname: string;
}

async function getLeantimeUserId(email: string): Promise<number | null> {
  try {
    if (!process.env.LEANTIME_TOKEN) {
      logger.error('[LEANTIME_TASKS] LEANTIME_TOKEN is not set in environment variables');
      return null;
    }

    logger.debug('[LEANTIME_TASKS] Fetching Leantime users', {
      emailHash: Buffer.from(email.toLowerCase()).toString('base64').slice(0, 12),
      apiUrlPresent: !!process.env.LEANTIME_API_URL,
      tokenLength: process.env.LEANTIME_TOKEN.length,
    });
    
    const headers: Record<string, string> = {
      'Content-Type': 'application/json',
      'X-API-Key': process.env.LEANTIME_TOKEN
    };

    const response = await fetch(`${process.env.LEANTIME_API_URL}/api/jsonrpc`, {
      method: 'POST',
      headers,
      body: JSON.stringify({
        jsonrpc: '2.0',
        method: 'leantime.rpc.users.getAll',
        id: 1
      }),
    });

    const responseText = await response.text();

    if (!response.ok) {
      logger.error('[LEANTIME_TASKS] Failed to fetch Leantime users', {
        status: response.status,
        statusText: response.statusText,
        headers: Object.fromEntries(response.headers.entries()),
      });
      return null;
    }

    let data;
    try {
      data = JSON.parse(responseText);
    } catch (e) {
      logger.error('[LEANTIME_TASKS] Failed to parse Leantime response', {
        error: e instanceof Error ? e.message : String(e),
      });
      return null;
    }

    if (!data.result || !Array.isArray(data.result)) {
      logger.error('[LEANTIME_TASKS] Invalid response format from Leantime users API');
      return null;
    }

    const users = data.result;
    const user = users.find((u: any) => u.username === email);
    
    if (user) {
      logger.debug('[LEANTIME_TASKS] Found Leantime user', {
        id: user.id,
        emailHash: Buffer.from(email.toLowerCase()).toString('base64').slice(0, 12),
      });
    } else {
      logger.warn('[LEANTIME_TASKS] No Leantime user found for username', {
        emailHash: Buffer.from(email.toLowerCase()).toString('base64').slice(0, 12),
      });
    }
    
    return user ? user.id : null;
  } catch (error) {
    logger.error('[LEANTIME_TASKS] Error fetching Leantime user ID', {
      error: error instanceof Error ? error.message : String(error),
    });
    return null;
  }
}

export async function GET(request: NextRequest) {
  try {
    const session = await getServerSession(authOptions);
    if (!session?.user?.email) {
      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
    }

    // Check for force refresh parameter
    const url = new URL(request.url);
    const forceRefresh = url.searchParams.get('refresh') === 'true';
    
    // Try to get data from cache if not forcing refresh
    if (!forceRefresh) {
      const cachedTasks = await getCachedTasksData(session.user.id);
      if (cachedTasks) {
        logger.debug('[LEANTIME_TASKS] Using cached tasks data', {
          userId: session.user.id,
          taskCount: Array.isArray(cachedTasks) ? cachedTasks.length : undefined,
        });
        return NextResponse.json(cachedTasks);
      }
    }

    logger.debug('[LEANTIME_TASKS] Fetching tasks for user', {
      emailHash: Buffer.from(session.user.email.toLowerCase()).toString('base64').slice(0, 12),
    });
    const userId = await getLeantimeUserId(session.user.email);
    
    if (!userId) {
      logger.error('[LEANTIME_TASKS] User not found in Leantime', {
        emailHash: Buffer.from(session.user.email.toLowerCase()).toString('base64').slice(0, 12),
      });
      return NextResponse.json({ error: "User not found in Leantime" }, { status: 404 });
    }

    logger.debug('[LEANTIME_TASKS] Fetching tasks for Leantime user ID', {
      userId,
    });
    const headers: Record<string, string> = {
      'Content-Type': 'application/json',
      'X-API-Key': process.env.LEANTIME_TOKEN!
    };

    const response = await fetch(`${process.env.LEANTIME_API_URL}/api/jsonrpc`, {
      method: 'POST',
      headers,
      body: JSON.stringify({
        jsonrpc: '2.0',
        method: 'leantime.rpc.tickets.getAll',
        params: {
          userId: userId,
          status: "all"
        },
        id: 1
      }),
    });

    const responseText = await response.text();
    logger.debug('[LEANTIME_TASKS] Tasks API response status', {
      status: response.status,
    });

    if (!response.ok) {
      logger.error('[LEANTIME_TASKS] Failed to fetch tasks from Leantime', {
        status: response.status,
        statusText: response.statusText,
      });
      throw new Error('Failed to fetch tasks from Leantime');
    }

    let data;
    try {
      data = JSON.parse(responseText);
    } catch (e) {
      logger.error('[LEANTIME_TASKS] Failed to parse tasks response', {
        error: e instanceof Error ? e.message : String(e),
      });
      throw new Error('Invalid response format from Leantime');
    }

    if (!data.result || !Array.isArray(data.result)) {
      logger.error('[LEANTIME_TASKS] Invalid response format from Leantime tasks API');
      throw new Error('Invalid response format from Leantime');
    }

    // Log only the number of tasks and their IDs
    logger.debug('[LEANTIME_TASKS] Received tasks summary', {
      count: data.result.length,
      idsSample: data.result.slice(0, 20).map((task: any) => task.id),
    });

    const tasks = data.result
      .filter((task: any) => {
        // Filter out any task (main or subtask) that has status Done (5)
        if (task.status === 5) {
          return false;
        }

        // Convert both to strings for comparison to handle any type mismatches
        const taskEditorId = String(task.editorId).trim();
        const currentUserId = String(userId).trim();
        
        // Only show tasks where the user is the editor
        const isUserEditor = taskEditorId === currentUserId;
        return isUserEditor;
      })
      .map((task: any) => ({
        id: task.id.toString(),
        headline: task.headline,
        projectName: task.projectName,
        projectId: task.projectId,
        status: task.status,
        dateToFinish: task.dateToFinish || null,
        milestone: task.type || null,
        details: task.description || null,
        createdOn: task.dateCreated,
        editedOn: task.editedOn || null,
        editorId: task.editorId,
        editorFirstname: task.editorFirstname,
        editorLastname: task.editorLastname,
        type: task.type || null,  // Added type field to identify subtasks
        dependingTicketId: task.dependingTicketId || null  // Added parent task reference
      }));

    logger.debug('[LEANTIME_TASKS] Filtered tasks for user', {
      userId,
      count: tasks.length,
    });
    
    // Cache the results
    await cacheTasksData(session.user.id, tasks);
    
    return NextResponse.json(tasks);
  } catch (error) {
    logger.error('[LEANTIME_TASKS] Error in tasks route', {
      error: error instanceof Error ? error.message : String(error),
    });
    return NextResponse.json(
      { error: "Failed to fetch tasks" },
      { status: 500 }
    );
  }
}