import { authFetch } from './auth'

const OLLAMA_URL = '/ollama/api/generate'

const OCR_PROMPT = `You are an invoice/bill OCR assistant. Extract the following fields from this image of a bill or invoice. Return ONLY valid JSON, no markdown, no explanation.

{
  "vendor": "company name on the bill",
  "vendor_address": "full address if visible",
  "invoice_number": "invoice/bill number",
  "date": "YYYY-MM-DD format",
  "due_date": "YYYY-MM-DD if visible, null otherwise",
  "subtotal": 0.00,
  "tax_gst": 0.00,
  "tax_qst": 0.00,
  "total": 0.00,
  "currency": "CAD",
  "items": [
    { "description": "line item description", "qty": 1, "rate": 0.00, "amount": 0.00 }
  ],
  "notes": "any other relevant text (account number, payment terms, etc.)"
}

If a field is not visible, set it to null. Always return valid JSON.`

/**
 * Send an image to Ollama Vision for bill/invoice OCR.
 * @param {string} base64Image — base64 encoded image (no data: prefix)
 * @returns {object} Parsed invoice data
 */
export async function ocrBill (base64Image) {
  // Strip data:image/...;base64, prefix if present
  const clean = base64Image.replace(/^data:image\/[^;]+;base64,/, '')

  const res = await authFetch(OLLAMA_URL, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      model: 'llama3.2-vision:11b',
      prompt: OCR_PROMPT,
      images: [clean],
      stream: false,
      options: {
        temperature: 0.1,
        num_predict: 2048,
      },
    }),
  })

  if (!res.ok) {
    const text = await res.text()
    throw new Error('OCR failed: ' + (text || res.status))
  }

  const data = await res.json()
  const raw = data.response || ''

  // Extract JSON from response (model might wrap it in markdown)
  const jsonMatch = raw.match(/\{[\s\S]*\}/)
  if (!jsonMatch) throw new Error('No JSON in OCR response')

  try {
    return JSON.parse(jsonMatch[0])
  } catch (e) {
    throw new Error('Invalid JSON from OCR: ' + e.message)
  }
}

/**
 * Check if Ollama is running and the vision model is available.
 */
export async function checkOllamaStatus () {
  try {
    const res = await authFetch('/ollama/api/tags')
    if (!res.ok) return { online: false, error: 'HTTP ' + res.status }
    const data = await res.json()
    const models = (data.models || []).map(m => m.name)
    const hasVision = models.some(m => m.includes('llama3.2-vision'))
    return { online: true, models, hasVision }
  } catch (e) {
    return { online: false, error: e.message }
  }
}