/**
 * Клиент для общения с HotelSync Agent на localhost:9000
 * Все кассовые операции идут напрямую через агент, минуя сервер
 */

const AGENT_URL = 'http://localhost:9000'
const TIMEOUT   = 30000  // 30 секунд для кассовых операций

async function agentReq<T>(
  method: 'GET' | 'POST',
  path: string,
  body?: object,
  timeout = TIMEOUT,
): Promise<T> {
  const res = await fetch(`${AGENT_URL}${path}`, {
    method,
    headers: body ? { 'Content-Type': 'application/json' } : undefined,
    body:    body ? JSON.stringify(body) : undefined,
    signal:  AbortSignal.timeout(timeout),
  })
  return res.json() as Promise<T>
}

// ── Типы ──────────────────────────────────────────────────────────────────────

export interface AgentIdentity {
  agent_id:         string
  workstation_id:   string
  workstation_name: string
  hostname:         string
  error?:           string
}

export interface ShiftStatus {
  state:          'closed' | 'open' | 'expired'
  shift_number:   number
  opened_at?:     string
  duration_min?:  number
  cash_sum?:      number
  receipt_count?: number
  cashier_name?:  string
}

export interface KktInfo {
  serial_number:  string
  model:          string
  fn_number:      string
  fn_expires_at?: string
  ofd_status:     'ok' | 'error' | 'no_connection'
  version:        string
}

export interface KktStatus {
  shift?:        ShiftStatus
  info?:         KktInfo
  dto_connected: boolean
  dto_version?:  string
}

export interface CashierInfo {
  name: string
  inn?:  string
}

export interface ReceiptItem {
  name:             string
  quantity:         number
  price:            number
  vat?:             'none' | 'vat0' | 'vat10' | 'vat20'
  payment_object?:  'commodity' | 'service'
}

export interface ReceiptData {
  type:            'sell' | 'sell_return'
  items:           ReceiptItem[]
  total:           number
  payment_type:    'cash' | 'card' | 'prepaid'
  cashier?:        CashierInfo
  customer_email?: string
  customer_phone?: string
  tax_system?:     number
}

export interface AgentResult {
  ok:              boolean
  error?:          string
  receipt_number?: string
  fiscal_sign?:    string
  shift_number?:   number
}

// ── API ───────────────────────────────────────────────────────────────────────

/** Проверяет что агент запущен и возвращает рабочее место. Timeout 500ms. */
export async function getIdentity(): Promise<AgentIdentity | null> {
  try {
    const data = await agentReq<AgentIdentity>('GET', '/identity', undefined, 500)
    if (data.error) return null
    return data
  } catch {
    return null
  }
}

export const kkt = {
  status: () =>
    agentReq<KktStatus>('GET', '/kkt/status', undefined, 5000),

  openShift: (cashier: CashierInfo, tax_system = 1) =>
    agentReq<AgentResult>('POST', '/kkt/shift/open', { cashier, tax_system }),

  closeShift: (cashier: CashierInfo) =>
    agentReq<AgentResult>('POST', '/kkt/shift/close', { cashier }),

  xReport: () =>
    agentReq<AgentResult>('POST', '/kkt/report/x', {}),

  cashIn: (amount: number, cashier: CashierInfo) =>
    agentReq<AgentResult>('POST', '/kkt/cash-in', { amount, cashier }),

  cashOut: (amount: number, cashier: CashierInfo) =>
    agentReq<AgentResult>('POST', '/kkt/cash-out', { amount, cashier }),

  printReceipt: (data: ReceiptData) =>
    agentReq<AgentResult>('POST', '/kkt/receipt', data),

  printReturn: (data: ReceiptData) =>
    agentReq<AgentResult>('POST', '/kkt/return', data),
}