const ALLOWED_EXTENSIONS = ['pdf', 'doc', 'docx', 'xls', 'xlsx', 'ppt', 'pptx', 'txt', 'md', 'csv']
const MAX_FILE_SIZE = 50 * 1024 * 1024

function validateEnterpriseWebsite(value) {
	const normalized = String(value || '').trim()
	if (!normalized) return '请输入企业官网，无官网请填写“无”'
	if (normalized === '无') return ''
	if (!/^https?:\/\/[^/\s?#]+(?:[/?#][^\s]*)?$/i.test(normalized)) return '请输入以http://或https://开头的企业官网'
	return ''
}

function validateBackgroundFile(file) {
	if (!file || !file.name || !file.size) return '请选择非空文件'
	if (file.name.length > 255) return '文件名不能超过255个字符'
	const ext = file.name.includes('.') ? file.name.split('.').pop().toLowerCase() : ''
	if (!ALLOWED_EXTENSIONS.includes(ext)) return '文件类型不支持'
	if (file.size > MAX_FILE_SIZE) return '单个文件不能超过50MB'
	return ''
}

module.exports = {
	ALLOWED_EXTENSIONS,
	MAX_FILE_SIZE,
	validateEnterpriseWebsite,
	validateBackgroundFile
}