import { NextRequest, NextResponse } from 'next/server'
import connectDB from '@/lib/mongodb'
import TopicModel from '@/models/topic'

// Track topic view (increment view count and daily analytics)
export async function POST(
  request: NextRequest,
  { params }: { params: Promise<{ slug: string }> }
) {
  try {
    const { slug } = await params

    if (!slug) {
      return NextResponse.json(
        {
          success: false,
          error: { message: 'Topic slug is required', code: 'MISSING_SLUG' },
        },
        { status: 400 }
      )
    }

    await connectDB()

    // Get current date in YYYY-MM-DD format
    const today = new Date().toISOString().split('T')[0]

    // Find and update the topic
    const topic = await TopicModel.findOneAndUpdate(
      { slug: slug, isDraft: false }, // Only track views for published posts
      {
        $inc: { views: 1 }, // Increment total views
        $push: {
          viewHistory: {
            $each: [{ date: today, count: 1 }],
            $slice: -30, // Keep only last 30 days
          },
        },
      },
      { 
        new: true, 
        projection: { views: 1, slug: 1, title: 1, authorId: 1 } // Include authorId for cache invalidation
      }
    )

    if (!topic) {
      return NextResponse.json(
        {
          success: false,
          error: { message: 'Topic not found or is a draft', code: 'TOPIC_NOT_FOUND' },
        },
        { status: 404 }
      )
    }


    return NextResponse.json({
      success: true,
      data: {
        slug: topic.slug,
        title: topic.title,
        views: topic.views,
      },
    })
  } catch (error) {
    console.error('View tracking error:', error)
    return NextResponse.json(
      {
        success: false,
        error: { message: 'Failed to track view', code: 'INTERNAL_ERROR' },
      },
      { status: 500 }
    )
  }
}