FlashSaleSystem/flash-sale-frontend/src/utils/image.ts

import defaultProductImage from '@/assets/default-product.svg'

export const DEFAULT_PRODUCT_IMAGE = defaultProductImage

const ABSOLUTE_URL_PATTERN = /^(https?:)?\/\//i
const SPECIAL_URL_PATTERN = /^(data:|blob:)/i

const normalizeBaseUrl = (value?: string) => {
  if (!value) return ''
  return value.endsWith('/') ? value.slice(0, -1) : value
}

export const resolveImageUrl = (value?: string | null) => {
  if (!value || !String(value).trim()) {
    return DEFAULT_PRODUCT_IMAGE
  }

  const imageUrl = String(value).trim()
  if (ABSOLUTE_URL_PATTERN.test(imageUrl) || SPECIAL_URL_PATTERN.test(imageUrl)) {
    return imageUrl
  }

  const baseUrl = normalizeBaseUrl(import.meta.env.VITE_API_BASE_URL)
  if (!baseUrl) {
    return imageUrl.startsWith('/') ? imageUrl : `/${imageUrl}`
  }

  return imageUrl.startsWith('/') ? `${baseUrl}${imageUrl}` : `${baseUrl}/${imageUrl}`
}

export const normalizeStorageImageUrl = (value?: string | null) => {
  if (!value || !String(value).trim()) {
    return ''
  }

  const imageUrl = String(value).trim()
  if (ABSOLUTE_URL_PATTERN.test(imageUrl)) {
    try {
      const parsed = new URL(imageUrl.startsWith('//') ? `http:${imageUrl}` : imageUrl)
      if (
        parsed.pathname.startsWith('/uploads/') ||
        parsed.pathname.startsWith('/images/') ||
        parsed.pathname.startsWith('/static/')
      ) {
        return parsed.pathname
      }
    } catch {
      return imageUrl
    }
  }

  return imageUrl
}

export const applyFallbackImage = (event: Event) => {
  const target = event.target as HTMLImageElement | null
  if (!target) return

  if (target.dataset.fallbackApplied === 'true') {
    return
  }

  target.dataset.fallbackApplied = 'true'
  target.onerror = null
  target.src = DEFAULT_PRODUCT_IMAGE
}