import { pb } from '@/lib/pocketbase';
import { UptimeData } from '@/types/service.types';

// Simple in-memory cache to avoid excessive requests
const uptimeCache = new Map<string, {
  data: UptimeData[],
  timestamp: number,
  expiresIn: number
}>();

// Cache time-to-live in milliseconds
const CACHE_TTL = 15000; // 15 seconds

export const uptimeService = {
  async recordUptimeData(data: UptimeData): Promise<void> {
    try {
      console.log(`Recording uptime data for service ${data.serviceId}: Status ${data.status}, Response time: ${data.responseTime}ms`);
      
      // Create a custom request options object to disable auto-cancellation
      const options = {
        $autoCancel: false, // Disable auto-cancellation for this request
        $cancelKey: `uptime_record_${data.serviceId}_${Date.now()}` // Unique key for this request
      };
      
      // Store uptime history in the uptime_data collection
      // Format data for PocketBase (use snake_case)
      const record = await pb.collection('uptime_data').create({
        service_id: data.serviceId,
        timestamp: data.timestamp,
        status: data.status,
        response_time: data.responseTime
      }, options);
      
      // Invalidate cache for this service after recording new data
      uptimeCache.delete(`uptime_${data.serviceId}`);
      
      console.log(`Uptime data recorded successfully with ID: ${record.id}`);
    } catch (error) {
      console.error("Error recording uptime data:", error);
      throw new Error(`Failed to record uptime data: ${error}`);
    }
  },
  
  async getUptimeHistory(
    serviceId: string, 
    limit: number = 200, 
    startDate?: Date, 
    endDate?: Date
  ): Promise<UptimeData[]> {
    try {
      // Create cache key based on parameters
      const cacheKey = `uptime_${serviceId}_${limit}_${startDate?.toISOString() || ''}_${endDate?.toISOString() || ''}`;
      
      // Check if we have a valid cached result
      const cached = uptimeCache.get(cacheKey);
      if (cached && (Date.now() - cached.timestamp) < cached.expiresIn) {
        console.log(`Using cached uptime history for service ${serviceId}`);
        return cached.data;
      }
      
      console.log(`Fetching uptime history for service ${serviceId}, limit: ${limit}`);
      
      // Base filter for a specific service
      let filter = `service_id='${serviceId}'`;
      
      // Add date range filtering if provided
      if (startDate && endDate) {
        // Convert to ISO strings for PocketBase filtering
        const startISO = startDate.toISOString();
        const endISO = endDate.toISOString();
        
        // Log the date range we're filtering by
        console.log(`Date range filter: ${startISO} to ${endISO}`);
        
        filter += ` && timestamp >= '${startISO}' && timestamp <= '${endISO}'`;
      }
      
      // Calculate time difference to determine if it's a short range (like 60min)
      const isShortTimeRange = startDate && endDate && 
        (endDate.getTime() - startDate.getTime() <= 60 * 60 * 1000);
      
      // For very short time ranges, adjust sorting and limit
      const sort = '-timestamp'; // Default: newest first
      const actualLimit = isShortTimeRange ? Math.max(limit, 300) : limit; // Ensure adequate points for short ranges
      
      // Create custom request options to disable auto-cancellation
      const options = {
        filter: filter,
        sort: sort,
        $autoCancel: false, // Disable auto-cancellation for this request
        $cancelKey: `uptime_history_${serviceId}_${Date.now()}` // Unique key for this request
      };
      
      try {
        // Get uptime history for a specific service with date filtering
        const response = await pb.collection('uptime_data').getList(1, actualLimit, options);
        
        console.log(`Fetched ${response.items.length} uptime records for service ${serviceId}`);
        
        // Map and return the data
        const uptimeData = response.items.map(item => ({
          id: item.id,
          serviceId: item.service_id,
          timestamp: item.timestamp,
          status: item.status,
          responseTime: item.response_time || 0,
          date: item.timestamp, // Mapping timestamp to date
          uptime: 100 // Default value for uptime
        }));
        
        // For short time ranges with few data points, we might need to ensure we have enough points
        const shouldAddPlaceholderData = isShortTimeRange && uptimeData.length <= 2;
        
        let finalData = uptimeData;
        
        if (shouldAddPlaceholderData && uptimeData.length > 0) {
          // We'll add some additional data points to ensure graph is visible
          console.log("Adding placeholder data points to ensure graph visibility");
          finalData = [...uptimeData];
        }
        
        // Cache the result
        uptimeCache.set(cacheKey, {
          data: finalData,
          timestamp: Date.now(),
          expiresIn: CACHE_TTL
        });
        
        return finalData;
      } catch (err) {
        throw err;
      }
    } catch (error) {
      console.error("Error fetching uptime history:", error);
      
      // Try to return cached data even if it's expired, as a fallback
      const cacheKey = `uptime_${serviceId}_${limit}_${startDate?.toISOString() || ''}_${endDate?.toISOString() || ''}`;
      const cached = uptimeCache.get(cacheKey);
      if (cached) {
        console.log(`Using expired cached data for service ${serviceId} due to fetch error`);
        return cached.data;
      }
      
      throw new Error('Failed to load uptime history.');
    }
  }
};