// Init Mini App
const tg = window.Telegram.WebApp
tg.ready()
tg.expand()  // fullscreen mode

// User data (auto từ Telegram)
const user = tg.initDataUnsafe.user
// { id, first_name, username, ... }

// Theme tokens
document.body.style.background =
  tg.themeParams.bg_color
document.body.style.color =
  tg.themeParams.text_color

// Hardware buttons
tg.BackButton.show()
tg.BackButton.onClick(() => router.back())

tg.MainButton.text = 'SHARE LINK'
tg.MainButton.color = '#22d3ee'
tg.MainButton.show()
tg.MainButton.onClick(shareReferral)

// Haptic feedback
tg.HapticFeedback.impactOccurred('medium')

// Verify auth on backend
fetch('/api/verify', {
  body: JSON.stringify({
    init_data: tg.initData
  })
})

// Share referral link natively
function shareReferral() {
  const tg = window.Telegram.WebApp
  const refCode = user.ref_code  // 'A4F2'
  const link = `https://t.me/funagency_bot` +
    `?start=ref_${refCode}`

  const msg = encodeURIComponent(
    `🎁 Tham gia FunAgency với link của tôi!\n` +
    `✔️ Giảm 20% fee tháng đầu\n` +
    `✔️ Free setup acc đầu tiên\n\n` +
    `${link}`
  )

  // Open native share sheet
  tg.openTelegramLink(
    `https://t.me/share/url?url=${msg}`
  )

  tg.HapticFeedback.notificationOccurred('success')
}

// QR code generator
function showQR() {
  const url = `https://api.qrserver.com/v1/` +
    `create-qr-code/?size=300x300&` +
    `data=${encodeURIComponent(link)}`
  showImage(url)
}

// Copy to clipboard
function copyLink() {
  navigator.clipboard.writeText(link)
  tg.HapticFeedback.notificationOccurred('success')
  showToast('Đã copy!')
}