/**
 * GET /api/media/:instanceId/:messageId
 * Download and serve media for a message
 *
 * This endpoint:
 * 1. Checks if media is already cached locally
 * 2. If not, downloads from WhatsApp using Baileys
 * 3. Caches the file locally
 * 4. Streams the file to the client
 */
import { createReadStream } from 'fs'
import { stat } from 'fs/promises'
import { downloadAndCacheMedia, getCachedMediaPath } from '../../../services/media/downloader'
import { sendStream } from 'h3'

export default defineEventHandler(async (event) => {
  const username = getHeader(event, 'x-authentik-username')
  if (!username) {
    throw createError({ statusCode: 401, message: 'Unauthorized' })
  }

  const instanceId = getRouterParam(event, 'instanceId')
  const messageId = getRouterParam(event, 'messageId')

  if (!instanceId || !messageId) {
    throw createError({ statusCode: 400, message: 'Missing instanceId or messageId' })
  }

  try {
    // First check if already cached
    let cached = await getCachedMediaPath(instanceId, messageId)

    // If not cached, download and cache
    if (!cached) {
      console.log(`[Media API] Downloading media for: ${messageId}`)
      const result = await downloadAndCacheMedia(instanceId, messageId)

      if (!result) {
        throw createError({
          statusCode: 404,
          message: 'Media not found or could not be downloaded'
        })
      }

      cached = { path: result.path, mimetype: result.mimetype }
    }

    // Get file stats for Content-Length
    const stats = await stat(cached.path)

    // Set response headers
    setHeader(event, 'Content-Type', cached.mimetype)
    setHeader(event, 'Content-Length', stats.size.toString())
    setHeader(event, 'Cache-Control', 'public, max-age=86400') // Cache for 24 hours

    // For documents, suggest download with filename
    const query = getQuery(event)
    if (query.download === 'true' || cached.mimetype.startsWith('application/')) {
      const filename = (query.filename as string) || `media-${messageId}`
      setHeader(event, 'Content-Disposition', `attachment; filename="${filename}"`)
    }

    // Stream the file
    const stream = createReadStream(cached.path)
    return sendStream(event, stream)
  } catch (error: any) {
    console.error(`[Media API] Error serving media ${messageId}:`, error)

    if (error.statusCode) {
      throw error
    }

    throw createError({
      statusCode: 500,
      message: 'Error retrieving media'
    })
  }
})