import { runOcr } from '../../utils/ocr/tesseractOcr'

/**
 * Server-side OCR for mobile return page.
 *
 * POST /api/mobile/ocr-scan
 * Body: multipart form-data with 'image' file field (JPEG/PNG binary)
 *   - Legacy fallback: JSON { image: "data:image/..." } (base64 data URL)
 *
 * Returns lines of recognized text. The heavy lifting (tesseract.js, deu+eng,
 * temp file, timeout, language cache) now lives in the shared util
 * server/utils/ocr/tesseractOcr.ts so the incoming-invoice pipeline reuses it.
 */

const OCR_TIMEOUT_MS = 60_000

export default defineEventHandler(async (event) => {
  const reqId = Date.now().toString(36) + Math.random().toString(36).slice(2, 6)
  console.log(`[OCR ${reqId}] Request received`)

  let imageBuffer: Buffer | null = null
  let filename = 'capture.jpg'

  const contentType = getRequestHeader(event, 'content-type') || ''

  try {
    if (contentType.includes('multipart/form-data')) {
      const formData = await readMultipartFormData(event)
      if (formData) {
        for (const part of formData) {
          if (part.name === 'image') {
            imageBuffer = part.data
            filename = part.filename || filename
          }
        }
      }
      console.log(`[OCR ${reqId}] Multipart parsed, size=${imageBuffer?.length ?? 0} bytes, filename=${filename}`)
    } else {
      // Legacy JSON base64 path
      const body = await readBody(event)
      const imageData: string | undefined = body?.image
      if (imageData && imageData.startsWith('data:image/')) {
        const base64 = imageData.split(',')[1] || ''
        imageBuffer = Buffer.from(base64, 'base64')
        console.log(`[OCR ${reqId}] JSON/base64 decoded, size=${imageBuffer.length} bytes`)
      }
    }
  } catch (err: any) {
    console.error(`[OCR ${reqId}] Failed to read request body:`, err?.message || err)
    throw createError({ statusCode: 400, statusMessage: 'Failed to read image from request' })
  }

  if (!imageBuffer || imageBuffer.length === 0) {
    console.error(`[OCR ${reqId}] No image data in request`)
    throw createError({ statusCode: 400, statusMessage: 'Image data is required' })
  }

  try {
    console.log(`[OCR ${reqId}] Starting OCR (deu+eng)`)
    const started = Date.now()
    const result = await runOcr(imageBuffer, { lang: 'deu+eng', timeoutMs: OCR_TIMEOUT_MS })
    console.log(`[OCR ${reqId}] Completed in ${Date.now() - started}ms, confidence=${result.confidence}, textLen=${result.text.length}`)

    if (result.lines.length === 0) {
      return { success: false, message: 'No text detected in image', lines: [] }
    }
    return { success: true, lines: result.lines, fullText: result.text, confidence: result.confidence }
  } catch (err: any) {
    console.error(`[OCR ${reqId}] Processing failed:`, err?.message || err, err?.stack)
    throw createError({
      statusCode: 500,
      statusMessage: 'OCR processing failed: ' + (err?.message || 'Unknown error')
    })
  }
})