import { NextRequest, NextResponse } from 'next/server'
import TopicModel, { transformToTopic } from '@/models/topic'
import { authMiddleware } from '@/lib/auth-middleware'

// GET /api/topic/slug/[slug] - Get topic by slug (for public viewing)
export async function GET(
  request: NextRequest,
  { params }: { params: Promise<{ slug: string }> }
) {
  try {
    const { slug } = await params
    
    if (!slug) {
      return NextResponse.json(
        {
          success: false,
          error: { message: 'Slug parameter is required', code: 'MISSING_SLUG' },
        },
        { status: 400 }
      )
    }
    
    const topic = await TopicModel.findOne({ slug }).lean()
    
    if (!topic) {
      return NextResponse.json(
        {
          success: false,
          error: { message: 'Topic not found', code: 'NOT_FOUND' },
        },
        { status: 404 }
      )
    }

    // Check if topic is draft and user is not the owner
    if (topic.isDraft) {
      const user = await authMiddleware(request)
      if (!user || user.id !== topic.authorId) {
        return NextResponse.json(
          {
            success: false,
            error: { message: 'Topic not found', code: 'NOT_FOUND' },
          },
          { status: 404 }
        )
      }
    }

    const transformedTopic = transformToTopic(topic)
    
    if (!transformedTopic) {
      return NextResponse.json(
        {
          success: false,
          error: { message: 'Failed to process topic data', code: 'PROCESSING_ERROR' },
        },
        { status: 500 }
      )
    }
    
    return NextResponse.json(
      {
        success: true,
        data: transformedTopic,
      },
      { status: 200 }
    )
  } catch (error) {
    console.error('Error fetching topic by slug:', error)
    return NextResponse.json(
      {
        success: false,
        error: { message: 'Failed to fetch topic', code: 'SERVER_ERROR' },
      },
      { status: 500 }
    )
  }
}