import { NextResponse } from 'next/server'
import type { NextRequest } from 'next/server'
import { getToken } from 'next-auth/jwt'
import {
  getAuthSessionCookieCandidates,
  resolveSecureAuthCookieFromRequest,
} from '@/lib/auth-cookie'

const API_CORS_ALLOWED_HEADERS =
  'X-CSRF-Token, X-Requested-With, Accept, Accept-Version, Content-Length, Content-MD5, Content-Type, Date, X-Api-Version, X-API-Key, Authorization, Cookie'

const DEPARTMENT_PAGE_PREFIXES = [
  '/assets/material-library',
  '/workspaces',
]

function isDepartmentPage(pathname: string): boolean {
  return pathname === '/' || DEPARTMENT_PAGE_PREFIXES.some((prefix) => pathname.startsWith(prefix))
}

function getAllowedCorsOrigins(request: NextRequest): Set<string> {
  const values = [
    request.nextUrl.origin,
    process.env.APP_PUBLIC_URL,
    process.env.NEXTAUTH_URL,
    ...(process.env.CORS_ALLOWED_ORIGINS || '').split(','),
  ]

  return new Set(values.map((value) => String(value || '').trim().replace(/\/+$/, '')).filter(Boolean))
}

function isAllowedCorsOrigin(request: NextRequest, requestOrigin: string | null): boolean {
  if (!requestOrigin) return true
  return getAllowedCorsOrigins(request).has(requestOrigin.replace(/\/+$/, ''))
}

// 注意：不在middleware中启动内存监控
// middleware使用Edge Runtime，不支持Node.js API
// 内存监控会在lib/memory-monitor.ts模块加载时自动启动（仅生产环境）

export async function middleware(request: NextRequest) {
  const { pathname } = request.nextUrl
  const requestOrigin = request.headers.get('origin')
  const isAuthEntryPage =
    pathname === '/login' ||
    pathname === '/dingtalk-entry' ||
    pathname === '/dingtalk-callback' ||
    pathname.startsWith('/performance-survey')

  // 处理API路由的CORS
  if (pathname.startsWith('/api/')) {
    const corsOriginAllowed = isAllowedCorsOrigin(request, requestOrigin)
    if (!corsOriginAllowed) {
      return NextResponse.json({ error: '不允许的跨域来源' }, { status: 403 })
    }

    // 处理OPTIONS预检请求
    if (request.method === 'OPTIONS') {
      const preflightResponse = new NextResponse(null, {
        status: 204,
        headers: {
          'Access-Control-Allow-Methods': 'GET,DELETE,PATCH,POST,PUT,OPTIONS',
          'Access-Control-Allow-Headers': API_CORS_ALLOWED_HEADERS,
          'Access-Control-Max-Age': '86400',
          'Vary': 'Origin',
        },
      })
      if (requestOrigin) {
        preflightResponse.headers.set('Access-Control-Allow-Credentials', 'true')
        preflightResponse.headers.set('Access-Control-Allow-Origin', requestOrigin)
      }
      return preflightResponse
    }

    // 为所有API响应添加CORS头
    const response = NextResponse.next()
    response.headers.set('Vary', 'Origin')
    if (requestOrigin) {
      response.headers.set('Access-Control-Allow-Credentials', 'true')
      response.headers.set('Access-Control-Allow-Origin', requestOrigin)
    }
    response.headers.set('Access-Control-Allow-Methods', 'GET,DELETE,PATCH,POST,PUT,OPTIONS')
    response.headers.set('Access-Control-Allow-Headers', API_CORS_ALLOWED_HEADERS)
    
    return response
  }

  // 处理需要认证的页面
  // /materials（素材库）与 /organization（组织管理）与首页同级，需登录；
  // /organization 沿用管理员角色门（与 /admin 一致）
  if (
    isDepartmentPage(pathname) ||
    pathname === '/materials' ||
    pathname.startsWith('/admin') ||
    pathname.startsWith('/organization')
  ) {
    const preferredSecureCookie = resolveSecureAuthCookieFromRequest(request)
    const cookieCandidates = getAuthSessionCookieCandidates(preferredSecureCookie)
    let token = null

    for (const cookieName of cookieCandidates) {
      token = await getToken({
        req: request,
        secret: process.env.NEXTAUTH_SECRET,
        cookieName,
        secureCookie: cookieName.startsWith('__Secure-'),
      })

      if (token) {
        break
      }
    }
    
    if (!token) {
      const url = new URL('/login', request.url)
      const redirectResponse = NextResponse.redirect(url)
      // 为重定向响应也添加缓存控制头
      redirectResponse.headers.set('Cache-Control', 'no-store, no-cache, must-revalidate, proxy-revalidate, max-age=0')
      redirectResponse.headers.set('Pragma', 'no-cache')
      redirectResponse.headers.set('Expires', '0')
      return redirectResponse
    }

    // 管理员页面需要管理员权限
    if (pathname.startsWith('/admin') || pathname.startsWith('/organization')) {
      const role = String((token as any)?.role || '')
      if (!['ADMIN', 'SYSTEM_ADMIN', 'DEPT_ADMIN'].includes(role)) {
        const url = new URL('/', request.url)
        const redirectResponse = NextResponse.redirect(url)
        // 为重定向响应也添加缓存控制头
        redirectResponse.headers.set('Cache-Control', 'no-store, no-cache, must-revalidate, proxy-revalidate, max-age=0')
        redirectResponse.headers.set('Pragma', 'no-cache')
        redirectResponse.headers.set('Expires', '0')
        return redirectResponse
      }
    }
  }

  // 检查是否有新版本部署（通过环境变量控制）
  // 只有在部署新版本时才禁用缓存，否则允许浏览器缓存以提高性能
  const disableCache = process.env.DISABLE_CACHE === 'true'
  const deploymentVersion = process.env.DEPLOYMENT_VERSION || process.env.BUILD_ID || ''
  
  // 获取客户端存储的版本号（通过 cookie）
  const clientVersion = request.cookies.get('app-version')?.value || ''
  
  // 判断是否需要禁用缓存：有新版本部署且客户端版本与服务器版本不同
  const shouldDisableCache = disableCache && deploymentVersion && clientVersion !== deploymentVersion
  
  const response = NextResponse.next()
  
  // 如果检测到新版本，设置版本号 cookie
  if (shouldDisableCache && deploymentVersion) {
    response.cookies.set('app-version', deploymentVersion, {
      path: '/',
      maxAge: 60 * 60 * 24 * 365, // 1年
      sameSite: 'lax',
    })
  }
  
  // 对于 HTML 页面，根据是否有新版本决定缓存策略
  if (
    isDepartmentPage(pathname) ||
    pathname === '/materials' ||
    pathname.startsWith('/admin') ||
    pathname.startsWith('/organization') ||
    pathname.startsWith('/share') ||
    pathname.startsWith('/edit') ||
    isAuthEntryPage ||
    pathname.endsWith('.html')
  ) {
    if (isDepartmentPage(pathname) || pathname.startsWith('/admin') || isAuthEntryPage || shouldDisableCache) {
      // 认证页面或有新版本时禁用缓存，避免用户范围数据被共享缓存
      response.headers.set('Cache-Control', 'private, no-store, no-cache, must-revalidate, proxy-revalidate, max-age=0')
      response.headers.set('Pragma', 'no-cache')
      response.headers.set('Expires', '0')
    } else {
      // 无新版本：允许浏览器缓存，提高性能
      response.headers.set('Cache-Control', 'public, max-age=3600, must-revalidate') // 缓存1小时
    }
  }
  
  // 对于 JS/CSS 等静态资源，使用版本号或时间戳来强制更新
  if (pathname.match(/\.(js|css|json|ico|png|jpg|jpeg|gif|svg|woff|woff2|ttf|eot)$/)) {
    if (shouldDisableCache) {
      // 有新版本：禁用缓存
      response.headers.set('Cache-Control', 'no-store, no-cache, must-revalidate, proxy-revalidate, max-age=0')
    } else {
      // 无新版本：长期缓存（Next.js 会自动添加版本号到文件名）
      response.headers.set('Cache-Control', 'public, max-age=31536000, immutable')
    }
  }
  
  return response
}

export const config = {
  matcher: [
    '/',
    '/assets/material-library/:path*',
    '/workspaces/:path*',
    '/login',
    '/materials',
    '/organization/:path*',
    '/admin/:path*',
    '/api/:path*',
    '/dingtalk-entry',
    '/dingtalk-callback',
    '/performance-survey/:path*',
  ],
}