const states = {
  unchanged: '已核对，业务字段没有变化',
  unavailable: '未能取得完整的修改前后数据',
  failed: '操作失败，未确认生效的改动',
  notCaptured: '此操作未记录字段对比'
}

function toParamRows(params) {
  if (!params || typeof params !== 'object') return []
  return Object.keys(params).map(key => ({ label: key, value: String(params[key]) }))
}

export function parseOperationAudit(text) {
  const empty = { action: '', target: '', changes: [], params: [], notice: '', structured: false }
  if (!text) return empty
  try {
    const data = JSON.parse(text)
    if (data && data.auditVersion === 1) {
      const target = data.target || {}
      const changes = data.state === 'changed' && Array.isArray(data.changes)
        ? data.changes.filter(c => c && typeof c.label === 'string' && typeof c.before === 'string' && typeof c.after === 'string') : []
      return {
        action: typeof data.action === 'string' ? data.action : '操作',
        target: target.id == null ? '' : '用户ID：' + target.id + (typeof target.name === 'string' && target.name ? '（' + target.name + '）' : ''),
        changes,
        params: toParamRows(data.params),
        notice: [states[data.state] || '', data.truncated ? '内容超出存储上限，部分改动未展示' : ''].filter(Boolean).join('；'),
        structured: true
      }
    }
    return { ...empty, action: '历史记录', notice: '历史记录未保存可验证的前后值' }
  } catch (e) { /* Legacy action strings are not JSON. */ }
  if (!text.startsWith('点击【')) return { ...empty, action: '历史记录', notice: '历史记录未保存可验证的前后值' }
  const separator = text.indexOf('|')
  if (separator < 0) return { ...empty, action: text, notice: '此记录未保存字段对比' }
  const changes = text.slice(separator + 1).split('\n').map(line => line.split('\t'))
    .filter(parts => parts.length === 3).map(parts => ({ label: parts[0], before: parts[1], after: parts[2] }))
  return { ...empty, action: text.slice(0, separator), changes, notice: changes.length ? '' : '历史记录未保存可验证的前后值' }
}