/**
 * OCR / Vision client — all calls go through targo-hub, which runs Gemini
 * 2.5 Flash. We deliberately do NOT call Ollama from the ops SPA because the
 * ops/ERPNext VM has no GPU; invoice OCR used to hit a local Ollama vision
 * model (llama3.2-vision), but that's now centralized in the hub so every
 * app (ops, field-as-ops `/j`, future client portal) gets the same model,
 * same prompt, same normalization.
 *
 * Endpoints used:
 *   POST {HUB_URL}/vision/barcodes   → { barcodes: string[] }
 *   POST {HUB_URL}/vision/equipment  → { brand, model, serial_number, mac_address, gpon_sn, hw_version, equipment_type, barcodes }
 *   POST {HUB_URL}/vision/invoice    → { vendor, vendor_address, invoice_number, date, due_date, subtotal, tax_gst, tax_qst, total, currency, items[], notes }
 *
 * All three are public (no Authentik header) — the hub rate-limits and logs.
 */

import { HUB_URL } from 'src/config/hub'

const VISION_BARCODES = `${HUB_URL}/vision/barcodes`
const VISION_EQUIPMENT = `${HUB_URL}/vision/equipment`
const VISION_INVOICE = `${HUB_URL}/vision/invoice`

/** Strip any `data:image/...;base64,` prefix — hub accepts either form but
 *  we normalize here so error messages + logs stay consistent. */
function stripDataUri (base64Image) {
  return String(base64Image || '').replace(/^data:image\/[^;]+;base64,/, '')
}

/**
 * Send a photo to Gemini (via hub) for bill/invoice OCR.
 * @param {string} base64Image — base64 or data URI
 * @returns {Promise<object>} Parsed invoice data (schema in targo-hub/lib/vision.js)
 * @throws {Error} on network/API failure — caller decides whether to retry
 */
export async function ocrBill (base64Image) {
  const res = await fetch(VISION_INVOICE, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ image: stripDataUri(base64Image) }),
  })
  if (!res.ok) {
    const text = await res.text().catch(() => '')
    throw new Error('Invoice OCR failed: ' + (text || res.status))
  }
  return res.json()
}

/**
 * Send a photo to Gemini (via hub) for generic barcode / serial extraction.
 * @param {string} base64Image — base64 or data URI
 * @returns {Promise<{ barcodes: string[] }>}
 * @throws {Error} on network/API failure — `useScanner` uses this signature
 *   to decide whether to queue the photo for retry (see isRetryable()).
 */
export async function scanBarcodes (base64Image) {
  const res = await fetch(VISION_BARCODES, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ image: base64Image }),
  })
  if (!res.ok) {
    const text = await res.text().catch(() => '')
    throw new Error('Vision scan failed: ' + (text || res.status))
  }
  const data = await res.json()
  return { barcodes: data.barcodes || [] }
}

/**
 * Structured equipment label scan — richer schema than scanBarcodes for
 * ONT/ONU/router labels. Unique to ops (was not in the old field client).
 * @param {string} base64Image — base64 or data URI
 * @returns {Promise<object>} See EQUIP_SCHEMA in targo-hub/lib/vision.js
 */
export async function scanEquipmentLabel (base64Image) {
  const res = await fetch(VISION_EQUIPMENT, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ image: base64Image }),
  })
  if (!res.ok) {
    const text = await res.text().catch(() => '')
    throw new Error('Equipment scan failed: ' + (text || res.status))
  }
  return res.json()
}

/**
 * Vision service health probe.
 *
 * Historically this pinged `/ollama/api/tags` to confirm the local vision
 * model was warm. Now that everything is on Gemini via the hub, we just
 * check the hub is reachable — the hub itself validates AI_API_KEY on
 * startup, so if it's up, Gemini works.
 */
export async function checkOllamaStatus () {
  try {
    const res = await fetch(`${HUB_URL}/health`, { method: 'GET' })
    if (!res.ok) return { online: false, error: 'HTTP ' + res.status }
    return { online: true, models: ['gemini-2.5-flash'], hasVision: true }
  } catch (e) {
    return { online: false, error: e.message }
  }
}