fix: harden habit input and lifecycle

frontend/src/lib/mvp-utils.ts

@@ -171,6 +171,84 @@ export function writeCountdownCache<T>(items: T[], archived: T[]) {
   countdownCache = { items, archived }
 }
 
+export type HabitFormValues = {
+  name: string
+  kind: 'boolean' | 'numeric'
+  target: number
+  max_value?: number | null
+  schedule_type: 'daily' | 'weekly' | 'monthly' | 'interval'
+  weekdays?: number[] | null
+  month_days?: number[] | null
+  interval_days?: number | null
+}
+
+export type HabitFormErrors = Partial<Record<keyof HabitFormValues, string>>
+
+export function normalizeRequiredName(input: string) {
+  const value = input.trim()
+  return { value, error: value ? '' : '名称不能为空，请输入至少一个可见字符。' }
+}
+
+export function validateHabitForm(form: HabitFormValues): HabitFormErrors {
+  const errors: HabitFormErrors = {}
+  if (!form.name.trim()) errors.name = '请输入习惯名称'
+  if (form.kind === 'numeric') {
+    if (!Number.isFinite(Number(form.target)) || Number(form.target) <= 0) errors.target = '目标值必须大于 0'
+    if (form.max_value != null && (!Number.isFinite(Number(form.max_value)) || Number(form.max_value) <= 0 || Number(form.max_value) < Number(form.target))) errors.max_value = '最大值不能小于目标值'
+  }
+  if (form.schedule_type === 'weekly') {
+    const values = form.weekdays ?? []
+    if (!values.length) errors.weekdays = '至少选择一个星期'
+    else if (new Set(values).size !== values.length) errors.weekdays = '星期不能重复'
+  }
+  if (form.schedule_type === 'monthly') {
+    const values = form.month_days ?? []
+    if (!values.length || values.some((day) => !Number.isInteger(day) || day < 1 || day > 31)) errors.month_days = '请输入 1 到 31 的日期'
+    else if (new Set(values).size !== values.length) errors.month_days = '日期不能重复'
+  }
+  if (form.schedule_type === 'interval' && (!Number.isInteger(Number(form.interval_days)) || Number(form.interval_days) < 1)) errors.interval_days = '间隔天数至少为 1'
+  return errors
+}
+
+export function changedHabitFields(before: HabitFormValues, after: HabitFormValues) {
+  const result: Partial<HabitFormValues> = {}
+  for (const key of Object.keys(after) as Array<keyof HabitFormValues>) {
+    const oldValue = before[key]
+    const newValue = after[key]
+    if (JSON.stringify(oldValue) !== JSON.stringify(newValue)) (result as Record<string, unknown>)[key] = newValue
+  }
+  return result
+}
+
+export function habitActionState(cell?: { scheduled?: boolean; paused?: boolean }, archived = false) {
+  if (archived) return { writable: false, reason: '该习惯已归档' }
+  if (cell?.paused) return { writable: false, reason: '今天已暂停' }
+  if (!cell?.scheduled) return { writable: false, reason: '今天未安排' }
+  return { writable: true, reason: '' }
+}
+
+export function formatHabitApiError(detail: unknown): string {
+  const source = detail && typeof detail === 'object' && !Array.isArray(detail) && 'detail' in detail
+    ? (detail as Record<string, unknown>).detail
+    : detail
+  const text = typeof source === 'string' ? source : ''
+  const mappings: Array<[string, string]> = [
+    ['暂停日不可记录正向进度', '今天已暂停，不能记录进度。'],
+    ['非计划日不可记录正向进度', '今天未安排该习惯，不能记录进度。'],
+    ['归档习惯不可修改', '该习惯已归档，不能继续操作。'],
+    ['请先归档再永久删除', '请先归档该习惯，再永久删除。'],
+  ]
+  for (const [needle, message] of mappings) if (text.includes(needle)) return message
+  if (Array.isArray(source)) {
+    const field = source.map((item) => item && typeof item === 'object' && Array.isArray((item as Record<string, unknown>).loc) ? ((item as Record<string, unknown>).loc as unknown[]).at(-1) : '').find(Boolean)
+    const fieldMessages: Record<string, string> = {
+      name: '名称不能为空，请输入至少一个可见字符。', weekdays: '每周计划至少选择一天，且不能重复。', month_days: '每月日期必须是 1–31，且不能重复。', interval_days: '间隔天数至少为 1。', target: '目标值必须大于 0。', max_value: '最大值必须大于 0。',
+    }
+    if (typeof field === 'string' && fieldMessages[field]) return fieldMessages[field]
+  }
+  return formatApiErrorDetail(source)
+}
+
 export function formatApiErrorDetail(detail: unknown): string {
   if (typeof detail === 'string') return detail
   if (Array.isArray(detail)) {