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";
import { fetchWithTimeout, fetchJsonWithTimeout } from '@/lib/utils/fetch-with-timeout';

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
    };

    let data;
    try {
      data = await fetchJsonWithTimeout(`${process.env.LEANTIME_API_URL}/api/jsonrpc`, {
        method: 'POST',
        timeout: 10000, // 10 seconds
        headers,
        body: JSON.stringify({
          jsonrpc: '2.0',
          method: 'leantime.rpc.users.getAll',
          id: 1
        }),
      });
    } catch (error) {
      logger.error('[LEANTIME_TASKS] Failed to fetch Leantime users', {
        error: error instanceof Error ? error.message : String(error),
      });
      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', {
        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;
  }
}

/**
 * Get all status labels for a user and identify which status values correspond to "done"
 * Returns a Set of status values (as strings) that are marked as "done"
 */
async function getDoneStatusValues(userId: number): Promise<Set<string>> {
  const doneStatusValues = new Set<string>();
  
  try {
    const headers: Record<string, string> = {
      'Content-Type': 'application/json',
      'X-API-Key': process.env.LEANTIME_TOKEN!
    };

    const data = await fetchJsonWithTimeout(`${process.env.LEANTIME_API_URL}/api/jsonrpc`, {
      method: 'POST',
      timeout: 10000,
      headers,
      body: JSON.stringify({
        jsonrpc: '2.0',
        method: 'leantime.rpc.Tickets.Tickets.getAllStatusLabelsByUserId',
        params: {
          userId: userId
        },
        id: 1
      }),
    });

    if (!data.result || typeof data.result !== 'object' || Array.isArray(data.result)) {
      console.log('[LEANTIME_TASKS] ⚠️ Invalid response format from getAllStatusLabelsByUserId, using fallback');
      console.log('[LEANTIME_TASKS] Response type:', typeof data.result, 'isArray:', Array.isArray(data.result));
      logger.warn('[LEANTIME_TASKS] Invalid response format from getAllStatusLabelsByUserId, using fallback');
      // Fallback to default values if API fails
      return new Set(['0', '3', '5']);
    }

    // data.result is an object where:
    // - Keys are project IDs (strings like "4", "5", "6", "457")
    // - Values are objects where keys are status numbers (strings like "0", "1", "2", "3", "4", "5", "-1")
    // - Each status object has: name, statusType, class, kanbanCol, sortKey
    
    console.log('[LEANTIME_TASKS] 📋 getAllStatusLabelsByUserId response structure:', {
      resultType: typeof data.result,
      isObject: typeof data.result === 'object',
      projectIds: Object.keys(data.result),
    });

    // Iterate through all projects
    Object.keys(data.result).forEach((projectId: string) => {
      const projectStatuses = data.result[projectId];
      
      if (projectStatuses && typeof projectStatuses === 'object') {
        // Iterate through all statuses in this project
        Object.keys(projectStatuses).forEach((statusKey: string) => {
          const statusInfo = projectStatuses[statusKey];
          
          if (statusInfo && typeof statusInfo === 'object') {
            const statusType = String(statusInfo.statusType || '').toUpperCase();
            const statusName = String(statusInfo.name || '').toLowerCase().trim();
            
            // Check if statusType is "DONE" or name contains "done"
            if (statusType === 'DONE' || statusName === 'done' || statusName.includes('done')) {
              // The statusKey IS the status number (e.g., "0", "3", "5", "-1")
              doneStatusValues.add(statusKey);
              console.log(`[LEANTIME_TASKS] ✅ Found done status: ${statusKey} in project ${projectId} (name: "${statusInfo.name}", statusType: "${statusType}")`);
            }
          }
        });
      }
    });

    console.log('[LEANTIME_TASKS] ✅ Identified done status values:', {
      doneStatusValues: Array.from(doneStatusValues),
      projectsCount: Object.keys(data.result).length,
    });
    logger.debug('[LEANTIME_TASKS] Identified done status values', {
      doneStatusValues: Array.from(doneStatusValues),
      projectsCount: Object.keys(data.result).length,
    });

    // If no done statuses found, use fallback
    if (doneStatusValues.size === 0) {
      logger.warn('[LEANTIME_TASKS] No done status labels found, using fallback values');
      return new Set(['0', '3', '5']);
    }

    return doneStatusValues;
  } catch (error) {
    logger.error('[LEANTIME_TASKS] Error fetching status labels, using fallback', {
      error: error instanceof Error ? error.message : String(error),
    });
    // Fallback to default values if API fails
    return new Set(['0', '3', '5']);
  }
}

export async function GET(request: NextRequest) {
  console.log('[LEANTIME_TASKS] 🔵 API CALLED - Starting request');
  try {
    const session = await getServerSession(authOptions);
    if (!session?.user?.email) {
      console.log('[LEANTIME_TASKS] ❌ Unauthorized - no session');
      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
    }
    console.log('[LEANTIME_TASKS] ✅ Session found, user:', session.user.email);

    // Check for force refresh parameter
    const url = new URL(request.url);
    const forceRefresh = url.searchParams.get('refresh') === 'true';
    
    // Get Leantime user ID first (needed for status labels)
    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 });
    }

    // Get done status values dynamically from Leantime status labels
    const doneStatusValues = await getDoneStatusValues(userId);
    console.log('[LEANTIME_TASKS] ✅ Done status values for filtering:', Array.from(doneStatusValues));
    logger.debug('[LEANTIME_TASKS] Done status values identified', {
      doneStatusValues: Array.from(doneStatusValues),
    });

    // Try to get data from cache if not forcing refresh
    if (!forceRefresh) {
      const cachedTasks = await getCachedTasksData(session.user.id);
      if (cachedTasks && Array.isArray(cachedTasks)) {
        // Filter out done tasks from cache using dynamic status values
        const filteredCachedTasks = cachedTasks.filter((task: any) => {
          const taskStatus = task.status;
          if (taskStatus !== null && taskStatus !== undefined) {
            const statusStr = String(taskStatus);
            if (doneStatusValues.has(statusStr)) {
              logger.debug('[LEANTIME_TASKS] Filtering out done task from cache', {
                id: task.id,
                headline: task.headline,
                status: taskStatus,
              });
              return false;
            }
          }
          return true;
        });
        
        if (filteredCachedTasks.length !== cachedTasks.length) {
          logger.debug('[LEANTIME_TASKS] Filtered done tasks from cache', {
            before: cachedTasks.length,
            after: filteredCachedTasks.length,
            removed: cachedTasks.length - filteredCachedTasks.length,
          });
          // Update cache with filtered tasks
          await cacheTasksData(session.user.id, filteredCachedTasks);
        }
        
        logger.debug('[LEANTIME_TASKS] Using cached tasks data', {
          emailHash: Buffer.from(session.user.email.toLowerCase()).toString('base64').slice(0, 12),
          taskCount: filteredCachedTasks.length,
        });
        // Return tasks with done statuses for frontend filtering
        return NextResponse.json({
          tasks: filteredCachedTasks,
          doneStatuses: Array.from(doneStatusValues),
        });
      }
    }

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

    let data;
    try {
      data = await fetchJsonWithTimeout(`${process.env.LEANTIME_API_URL}/api/jsonrpc`, {
        method: 'POST',
        timeout: 10000, // 10 seconds
        headers,
        body: JSON.stringify({
          jsonrpc: '2.0',
          method: 'leantime.rpc.tickets.getAll',
          params: {
            userId: userId,
            status: "all"
          },
          id: 1
        }),
      });
    } catch (error) {
      logger.error('[LEANTIME_TASKS] Failed to fetch tasks from Leantime', {
        error: error instanceof Error ? error.message : String(error),
      });
      throw new Error('Failed to fetch tasks 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');
    }

    console.log('[LEANTIME_TASKS] 🔍 RAW DATA FROM LEANTIME - Total tasks:', data.result.length);
    // Log RAW data from Leantime to see exact status values (using console.log so it shows in production)
    data.result.forEach((task: any) => {
      console.log(`[LEANTIME_TASKS] Task ID: ${task.id}, Headline: ${task.headline}, Status: ${task.status} (type: ${typeof task.status}), EditorId: ${task.editorId}`);
    });

    // Log detailed status information before filtering
    const statusBreakdownBefore = data.result.reduce((acc: any, task: any) => {
      const status = task.status;
      const statusKey = String(status);
      if (!acc[statusKey]) {
        acc[statusKey] = { count: 0, type: typeof status, sample: [] };
      }
      acc[statusKey].count++;
      if (acc[statusKey].sample.length < 3) {
        acc[statusKey].sample.push({ id: task.id, headline: task.headline });
      }
      return acc;
    }, {});
    
    logger.debug('[LEANTIME_TASKS] Received tasks summary', {
      count: data.result.length,
      statusBreakdown: statusBreakdownBefore,
      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
        // Use dynamic status values from Leantime status labels
        const taskStatus = task.status;
        if (taskStatus !== null && taskStatus !== undefined) {
          const statusStr = String(taskStatus);
          if (doneStatusValues.has(statusStr)) {
            logger.debug('[LEANTIME_TASKS] Filtering out done task', {
              id: task.id,
              headline: task.headline,
              status: taskStatus,
              statusType: typeof taskStatus,
            });
            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;
        
        if (!isUserEditor) {
          console.log(`[LEANTIME_TASKS] ⚠️ Task filtered - user is not editor: ID=${task.id}, EditorId=${taskEditorId}, UserId=${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
      }));

    // Log detailed status information for debugging
    const statusBreakdown = tasks.reduce((acc: any, task: any) => {
      const status = task.status;
      const statusKey = String(status);
      if (!acc[statusKey]) {
        acc[statusKey] = 0;
      }
      acc[statusKey]++;
      return acc;
    }, {});
    
    logger.debug('[LEANTIME_TASKS] Filtered tasks for user', {
      userId,
      count: tasks.length,
      statusBreakdown,
      sampleTasks: tasks.slice(0, 5).map((t: any) => ({
        id: t.id,
        headline: t.headline,
        status: t.status,
        statusType: typeof t.status,
      })),
    });
    
    // Cache the results
    await cacheTasksData(session.user.id, tasks);
    
    // Return tasks with done statuses for frontend filtering
    return NextResponse.json({
      tasks: tasks,
      doneStatuses: Array.from(doneStatusValues),
    });
  } 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 }
    );
  }
}