/**
 * Non-component helpers for settings sections: the busy/notice/error save trio
 * plus formatting and field-styling utilities. Kept out of
 * settings-primitives.tsx so that file stays export-only-components
 * (react-refresh requirement).
 */

import { getLocale, translate } from '@app/i18n'
import { ApiFailure } from '@app/lib'
import { useState } from 'react'

/**
 * Fields lean on the shared stylesheet for the border weight, corner radius and
 * focus ring, so this only carries layout and type.
 */
export const inputCls =
  'input h-10 w-full max-w-[440px] rounded-md border-shell-hairline bg-shell-field px-3 text-[13.5px] text-shell-ink'
export const selectCls =
  'select h-10 w-full max-w-[440px] rounded-md border-shell-hairline bg-shell-field px-3 text-[13.5px] text-shell-ink'
export const textareaCls =
  'textarea w-full max-w-[440px] rounded-md border-shell-hairline bg-shell-field px-3 py-2 text-[13.5px] text-shell-ink'

/**
 * `ApiFailure` carries the server's own wording; a plain Error thrown by a
 * section is local copy written for the user (size limits, missing ids), so it
 * is shown as-is rather than replaced by the generic fallback.
 */
export function errText(err: unknown) {
  if (err instanceof ApiFailure) return err.message
  if (err instanceof Error && err.message) return err.message
  return translate(getLocale(), 'ui.actionFailed')
}

export function useSave() {
  const [busy, setBusy] = useState(false)
  const [notice, setNotice] = useState<string | null>(null)
  const [error, setError] = useState<string | null>(null)
  async function run<T>(fn: () => Promise<T>, ok?: string | ((value: T) => string)) {
    setBusy(true)
    setNotice(null)
    setError(null)
    try {
      const value = await fn()
      if (ok) setNotice(typeof ok === 'function' ? ok(value) : ok)
    } catch (err) {
      setError(errText(err))
    } finally {
      setBusy(false)
    }
  }
  return { busy, notice, error, run }
}

/**
 * Rust's time crate emits `… +00:00:00` (seconds inside the UTC offset), which
 * `Date` rejects — fold it back to `+00:00` before parsing. Every date the
 * settings read out of the space API goes through here.
 */
export function parseDate(value?: string | null): Date | null {
  if (!value) return null
  const date = new Date(value.replace(/([+-]\d{2}):(\d{2}):(\d{2})$/, '$1:$2'))
  return Number.isNaN(date.getTime()) ? null : date
}

export function fmtDate(value?: string | null) {
  if (!value) return '—'
  const date = parseDate(value)
  if (!date) return value
  // Locale-aware so the settings tables switch conventions along with the UI
  // language (the old hardcoded `zh-CN` made the whole app read as Chinese).
  return new Intl.DateTimeFormat(getLocale(), { dateStyle: 'medium', timeStyle: 'short' }).format(date)
}

/** `2026-09-06T02:00:00+00:00` → the `YYYY-MM-DDTHH:mm` that `<input type=date>` wants. */
export function toDateInput(value?: string | null) {
  const date = parseDate(value)
  if (!date) return ''
  const pad = (n: number) => String(n).padStart(2, '0')
  return `${date.getFullYear()}-${pad(date.getMonth() + 1)}-${pad(date.getDate())}T${pad(date.getHours())}:${pad(date.getMinutes())}`
}

/** Read a file as the `data_base64` payload the image endpoints expect. */
export function fileToBase64(file: File): Promise<string> {
  return new Promise((resolve, reject) => {
    const reader = new FileReader()
    reader.onerror = () => reject(new Error(translate(getLocale(), 'ui.readFileFailed')))
    reader.onload = () => {
      const result = String(reader.result ?? '')
      // `data:image/png;base64,AAAA…` → the part after the comma.
      resolve(result.slice(result.indexOf(',') + 1))
    }
    reader.readAsDataURL(file)
  })
}