import { defineEventHandler, getRequestURL, sendRedirect } from 'h3'
// @ts-ignore: runtime module from @nuxt/content
import { queryContent } from '#content/server'

export default defineEventHandler(async (event) => {
  const url = getRequestURL(event)
  const path = url.pathname

  // Match top-level locale-prefixed paths like /en/slug, /zh/slug, /zh-hant/slug
  const match = path.match(/^\/(en|zh|zh-hant)(\/.*)$/)
  if (!match) return

  const locale = match[1]
  const rest = match[2] // includes leading '/'

  try {
    // Check if a content doc exists for this locale and slug
    const doc = await queryContent(event)
      .where({ _locale: locale, _path: `/${locale}${rest}` })
      .findOne()

    // If not found by _path, also try querying by normalized path with _locale filter
    const normalized = rest // e.g., /getting-started-aws-ec2
    const fallback = doc || await queryContent(event)
      .where({ _locale: locale })
      .path(normalized)
      .findOne()

    if (fallback) {
      const appPrefix = locale === 'en' ? '' : `/${locale}`
      const target = `${appPrefix}/blog${rest}`
      // 301 permanent redirect
      return sendRedirect(event, target, 301)
    }
  } catch {
    // Ignore errors and let normal routing continue
  }
})