import Series from '../../models/series.js'
import Event from '../../models/event.js'
import { connectDB } from '../../utils/mongoose.js'

export default defineEventHandler(async (event) => {
  try {
    await connectDB()
    
    // Fetch all series
    const series = await Series.find({ isActive: true })
      .sort({ createdAt: -1 })
      .lean()
    
    // For each series, get event count and statistics
    const seriesWithStats = await Promise.all(
      series.map(async (s) => {
        const events = await Event.find({ 
          'series.id': s.id,
          'series.isSeriesEvent': true
        }).select('_id startDate endDate registrations').lean()
        
        const now = new Date()
        const eventCount = events.length
        const completedEvents = events.filter(e => e.endDate < now).length
        const upcomingEvents = events.filter(e => e.startDate > now).length
        
        const firstEventDate = events.length > 0 ? 
          Math.min(...events.map(e => new Date(e.startDate))) : null
        const lastEventDate = events.length > 0 ? 
          Math.max(...events.map(e => new Date(e.endDate))) : null
        
        let status = 'upcoming'
        if (lastEventDate && lastEventDate < now) {
          status = 'completed'
        } else if (firstEventDate && firstEventDate <= now && lastEventDate && lastEventDate >= now) {
          status = 'active'
        }
        
        return {
          ...s,
          eventCount,
          completedEvents,
          upcomingEvents,
          startDate: firstEventDate,
          endDate: lastEventDate,
          status,
          totalRegistrations: events.reduce((sum, e) => sum + (e.registrations?.length || 0), 0)
        }
      })
    )
    
    return seriesWithStats
  } catch (error) {
    console.error('Error fetching series:', error)
    throw createError({
      statusCode: 500,
      statusMessage: 'Failed to fetch series'
    })
  }
})