import { defineEventHandler, getQuery, setHeader } from 'h3'
import { useRuntimeConfig } from '#imports'
import { getTenantFromContext } from '../utils/tenant'
import { $fetch } from 'ofetch'

/**
 * 动态站点地图
 * GET /api/sitemap.xml
 * 根据当前租户的页面列表动态生成 sitemap.xml
 *
 * 覆盖范围：
 *   - 静态页：首页 + 三大模块列表根页（/article /product /case）
 *   - CMS 单页（/page slug 对应的顶层路由，如 /about /contact）
 *   - 文章 / 产品 / 案例 详情页（仅已发布 status=0、未删除 deleted=0）
 */
interface SitemapUrl {
  loc: string
  priority: string
  changefreq: string
  lastmod: string
}

function escapeXml(s: string): string {
  return s
    .replace(/&/g, '&')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
    .replace(/"/g, '&quot;')
    .replace(/'/g, '&apos;')
}

/** 从列表返回中提取 list 数组（兼容 article 原始包装与 product/case 归一化结构） */
function extractList(res: any): any[] {
  if (!res) return []
  const data = res.data !== undefined ? res.data : res
  if (data && Array.isArray(data.list)) return data.list
  if (Array.isArray(res?.data?.list)) return res.data.list
  if (Array.isArray(data)) return data
  return []
}

/** 从列表项中提取唯一 id（各模块主键字段名不同） */
function pickId(item: any, keys: string[]): string | number | null {
  for (const k of keys) {
    if (item?.[k] != null) return item[k]
  }
  return null
}

export default defineEventHandler(async (event) => {
  const config = useRuntimeConfig()
  const ctx = getTenantFromContext(event, config)
  const query = getQuery(event)
  const modulesApiBase = config.public.modulesApiBase as string

  const origin = `https://${ctx.host || ''}`
  const now = new Date().toISOString()

  const urls: SitemapUrl[] = [
    { loc: '/', priority: '1.0', changefreq: 'daily', lastmod: now },
    { loc: '/article', priority: '0.9', changefreq: 'daily', lastmod: now },
    { loc: '/product', priority: '0.9', changefreq: 'daily', lastmod: now },
    { loc: '/case', priority: '0.9', changefreq: 'daily', lastmod: now }
  ]

  // ===== 单页 slug（/about /contact 等顶层路由） =====
  try {
    const res = await $fetch<{ data?: { list?: any[] } } | any[]>('/cms/cms-website/pageAll', {
      baseURL: modulesApiBase,
      headers: { TenantId: ctx.tenantId }
    })
    const list = Array.isArray(res) ? res : res?.data?.list || res?.data || []
    for (const p of list) {
      if (p?.slug && p.slug !== 'index') {
        urls.push({
          loc: `/${p.slug}`,
          priority: '0.8',
          changefreq: 'weekly',
          lastmod: p.updateTime || now
        })
      }
    }
  } catch {
    // 单页接口异常不影响详情页收录
  }

  // ===== 文章 / 产品 / 案例详情（分页拉取，仅已发布） =====
  const fetchDetailUrls = async (
    apiPath: string,
    urlPrefix: string,
    idKeys: string[]
  ) => {
    const limit = 500
    let page = 1
    // 安全上限：单 sitemap 文件 URL 上限 50,000
    while (urls.length < 50000) {
      let list: any[] = []
      try {
        const res = await $fetch(apiPath, {
          baseURL: modulesApiBase,
          headers: { TenantId: ctx.tenantId },
          query: { page, limit, status: 0, deleted: 0 }
        })
        list = extractList(res)
      } catch {
        break
      }

      for (const item of list) {
        const idVal = pickId(item, idKeys)
        if (idVal == null) continue
        urls.push({
          loc: `/${urlPrefix}/${idVal}`,
          priority: '0.7',
          changefreq: 'weekly',
          lastmod: item.updateTime || item.publishTime || item.createTime || now
        })
      }

      if (list.length < limit) break
      page++
    }
  }

  await fetchDetailUrls('/cms/cms-article/page', 'article', ['id', 'articleId'])
  await fetchDetailUrls('/cms/cms-product/page', 'product', ['id', 'productId'])
  await fetchDetailUrls('/cms/cms-case/page', 'case', ['id', 'caseId', 'caseItemId'])

  const xml = `<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
${urls
  .map(
    (u) => `  <url>
    <loc>${escapeXml(origin + u.loc)}</loc>
    <lastmod>${u.lastmod}</lastmod>
    <changefreq>${u.changefreq}</changefreq>
    <priority>${u.priority}</priority>
  </url>`
  )
  .join('\n')}
</urlset>`

  setHeader(event, 'Content-Type', 'application/xml')
  return xml
})