/**
 * 按路由加载页面级翻译到 page 命名空间
 * 路由 /dice/lottery_pool_config/index -> 加载 langs/{locale}/dice/lottery_pool_config.json
 */
import i18n from '@/locales'
import { LanguageEnum } from '@/enums/appEnum'

/** 路由 path 到 locale 文件路径的映射（无前导斜杠、无 /index） */
export function getPageLocalePath(routePath: string): string | null {
  if (!routePath || routePath === '/') return null
  const normalized = routePath.replace(/\?.*$/, '').replace(/#.*$/, '').replace(/\/$/, '')
  const withoutIndex = normalized.replace(/\/index$/i, '') || '/'
  const path = withoutIndex.replace(/^\//, '') || ''
  if (!path) return null
  return path
}

type PageLocaleModule = { default: Record<string, unknown> }

const enModules = import.meta.glob<PageLocaleModule>('./langs/en/**/*.json')
const zhModules = import.meta.glob<PageLocaleModule>('./langs/zh/**/*.json')

function getModuleKey(locale: string, path: string): string {
  return `./langs/${locale}/${path}.json`
}

let lastLoadedPath: string | null = null
let lastLoadedLocale: string | null = null

/** 获取当前语言（locale 可能是 string 或 Ref） */
function getCurrentLocale(): string {
  const loc = i18n.global.locale
  return typeof loc === 'string' ? loc : (loc as { value: string }).value
}

/**
 * 加载并合并页面翻译到 i18n 的 page 命名空间
 */
export async function loadPageLocale(routePath: string): Promise<void> {
  const path = getPageLocalePath(routePath)
  if (!path) {
    clearPageLocale()
    return
  }
  const locale = getCurrentLocale()
  const modules = locale === LanguageEnum.EN ? enModules : zhModules

  const tryPaths: string[] = [path]
  // 兼容别名路由：菜单 path 为短名但 locale 文件位于模块子目录
  // 例如：/user -> system/user，/game -> dice/game
  if (!path.includes('/')) {
    tryPaths.push(`system/${path}`)
    // 兜底：在任意一级子目录下查找同名文件
    const suffix = `/${path}.json`
    const localePrefix = `./langs/${locale}/`
    for (const key of Object.keys(modules)) {
      if (key.startsWith(localePrefix) && key.endsWith(suffix)) {
        const candidate = key.slice(localePrefix.length, -'.json'.length)
        if (!tryPaths.includes(candidate)) {
          tryPaths.push(candidate)
        }
      }
    }
  }

  let matchedPath: string | null = null
  let loader: (() => Promise<PageLocaleModule>) | undefined
  for (const p of tryPaths) {
    const key = getModuleKey(locale, p)
    const l = modules[key]
    if (l) {
      matchedPath = p
      loader = l
      break
    }
  }
  if (!loader) {
    clearPageLocale()
    return
  }
  if (lastLoadedPath === matchedPath && lastLoadedLocale === locale) {
    return
  }
  try {
    const mod = await loader()
    const message = mod?.default
    if (message && typeof message === 'object') {
      i18n.global.mergeLocaleMessage(locale, { page: message })
      lastLoadedPath = matchedPath
      lastLoadedLocale = locale
    }
  } catch {
    clearPageLocale()
  }
}

/**
 * 清除 page 命名空间（进入无页面翻译的路由时调用）
 */
export function clearPageLocale(): void {
  const locale = getCurrentLocale()
  const messages = i18n.global.getLocaleMessage(locale) as Record<string, unknown>
  if (messages && 'page' in messages) {
    const next = { ...messages }
    delete next.page
    i18n.global.setLocaleMessage(locale, next)
  }
  lastLoadedPath = null
  lastLoadedLocale = null
}

/**
 * 语言切换时清空缓存，下次进入页面会重新加载
 */
export function invalidatePageLocaleCache(): void {
  lastLoadedPath = null
  lastLoadedLocale = null
}