/**
 * repeater / group 行的纯函数：新行默认值、行 ID、listPreview 摘要与预览。
 * inline 与 list-modal 两种渲染共用。
 */
let rowIdCounter = 0

export function createRepeaterRowId() {
  return `rpt_${Date.now()}_${++rowIdCounter}`
}

export function createRepeaterRow(fields) {
  const row = { _id: createRepeaterRowId() }
  for (const field of (Array.isArray(fields) ? fields : [])) {
    // UI-only chrome rows (notice / alert) are presentation only.
    if (field.ui_only) continue
    if (field.default !== undefined) {
      row[field.key] = field.default
    } else if (field.type === 'switch') {
      row[field.key] = false
    } else if (field.type === 'checkbox' || field.type === 'repeater') {
      row[field.key] = []
    } else {
      row[field.key] = ''
    }
  }
  return row
}

/** time/unit 形态的时长摘要：0 视为永久，其余按 day/month 补单位。 */
function rowDuration(row, cfg) {
  if (!cfg.descKey) return ''
  const raw = row[cfg.descKey]
  if (raw === '' || raw == null) return ''
  const amount = Number(raw)
  if (!Number.isFinite(amount)) return String(raw)
  if (amount <= 0) return '永久'
  if (!cfg.descUnitKey) return String(raw)
  const unit = String(row[cfg.descUnitKey] || '')
  if (unit === 'month') return `${amount} 个月`
  if (unit === 'day') return `${amount} 天`
  return String(raw)
}

/** 未配置 titleKey 时，取首个值为非空字符串/数字的字段作为标题。 */
function fallbackTitleKey(row, fields) {
  if (row.title != null && String(row.title).trim() !== '') return 'title'
  for (const field of (Array.isArray(fields) ? fields : [])) {
    if (field.ui_only) continue
    const value = row[field.key]
    if ((typeof value === 'string' && value.trim() !== '') || typeof value === 'number') return field.key
  }
  return 'title'
}

/** 收起态标题行上的一行摘要，取自 listPreview 配置。 */
export function repeaterRowSummary(row, cfg = {}, fields = []) {
  if (!row) return ''
  const title = String(row[cfg.titleKey || fallbackTitleKey(row, fields)] ?? '').trim()
  const prefix = String(cfg.prefix || '')
  if (title === '') return prefix
  const duration = rowDuration(row, cfg)
  return duration ? `${prefix}${title} · ${duration}` : `${prefix}${title}`
}

/** list-modal 卡片预览：图标 / 自定义图标 HTML / 图标类 / 标题 / 描述。 */
export function repeaterRowPreview(row, cfg = {}) {
  const read = (key) => String(row?.[key] || '').trim()
  const desc = read(cfg.descKey || 'desc') || read(cfg.urlKey || 'url')
  return {
    icon: read(cfg.iconKey || 'icon'),
    customIcon: read(cfg.customIconKey || 'custom_icon'),
    iconClass: read(cfg.iconClassKey || 'icon_class'),
    title: read(cfg.titleKey || 'title') || '未命名卡片',
    desc: desc || '暂无描述',
  }
}