import { Hono } from 'hono'
import { basename, resolve } from 'node:path'

import { WS_AUTH_PROTOCOL } from '@oj2/contract'

import { authenticateWebSocket, loadJwtSecret } from './auth/session'
import { config } from './config'
import { adminRoutes } from './routes/admin'
import { authRoutes } from './routes/auth'
import { accountRoutes } from './routes/account'
import { judgeServerRoutes } from './routes/judge-server'
import { contestRoutes } from './routes/contest'
import { contentRoutes } from './routes/content'
import { classroomRoutes } from './routes/classroom'
import { rankingRoutes } from './routes/ranking'
import { problemsetRoutes } from './routes/problemset'
import { achievementRoutes } from './routes/achievement'
import { aiRoutes } from './routes/ai'
import { flowchartRoutes } from './routes/flowchart'
import { problemRoutes } from './routes/problem'
import { problemStatsRoutes } from './routes/problem-stats'
import { submissionRoutes } from './routes/submission'
import { trialRunRoutes } from './routes/trial-run'
import { siteRoutes } from './routes/site'
import { scanPendingChallenges } from './services/challenge'
import { bridgeSubmissionEvents, isAllowedWebSocketOrigin, startSessionSweep, submissionWebSocketHandler, type SubmissionSocketData } from './websocket'

const app = new Hono()

app.get('/health', (c) => c.json({ ok: true }))
app.route('/api', authRoutes)
app.route('/api', accountRoutes)
app.route('/api', siteRoutes)
app.route('/api', contestRoutes)
app.route('/api', contentRoutes)
app.route('/api', classroomRoutes)
app.route('/api', rankingRoutes)
app.route('/api', problemsetRoutes)
app.route('/api', achievementRoutes)
app.route('/api', aiRoutes)
app.route('/api', flowchartRoutes)
app.route('/api', problemRoutes)
app.route('/api', problemStatsRoutes)
app.route('/api', submissionRoutes)
app.route('/api', trialRunRoutes)
app.route('/api', judgeServerRoutes)
app.route('/api/admin', adminRoutes)

app.onError((error, c) => {
  console.error(error)
  return c.json({ error: { code: 'internal-error', message: 'Internal server error' } }, 500)
})

/** 头像取不到时的占位图，避免每个没设头像的学生都打一次 404 */
const DEFAULT_AVATAR_SVG =
  '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 128 128"><rect width="128" height="128" rx="64" fill="#e2e8f0"/><circle cx="64" cy="48" r="24" fill="#94a3b8"/><path d="M20 120c4-28 22-42 44-42s40 14 44 42" fill="#94a3b8"/></svg>'

/**
 * 伺服 /public 下的用户上传文件。
 *
 * 只取路径最后一段并要求它和原样一致 —— `..`、子目录、编码过的斜杠都会在这里被拒，
 * 拼接进 resolve() 的永远只是一个纯文件名。
 *
 * 生产环境这些请求也走后端（Caddy 把 /public/* 整段反代过来），不让 Caddy 直接读盘：
 * 这样开发（Vite 代理）和生产是同一条代码路径，少一处只在服务器上才出错的差异。
 */
async function serveUpload(pathname: string, prefix: string, directory: string) {
  const decoded = decodeURIComponent(pathname)
  const filename = basename(decoded)
  if (!filename || filename !== decoded.slice(prefix.length + 1)) {
    return new Response('Not found', { status: 404 })
  }
  const file = Bun.file(resolve(directory, filename))
  if (await file.exists()) {
    // 文件名由后端生成且内容不变，可以放心长缓存
    return new Response(file, {
      headers: {
        'cache-control': 'public, max-age=86400',
        // 线上 Caddy 也加了这个头，这里再加一道：content-type 按扩展名配，
        // 不让浏览器自己嗅探成 HTML 去执行
        'x-content-type-options': 'nosniff',
      },
    })
  }
  return null
}

await loadJwtSecret()

const server = Bun.serve<SubmissionSocketData>({
  port: config.port,
  // Bun 默认 10 秒没有字节往来就掐连接，而且不报任何错。AI 的 SSE 两条路都会静默
  // 超过 10 秒：streamWhole 在 produce 期间每 15 秒才发一次心跳，streamChat 等首
  // token 也常过 10 秒 —— 学生看到的就是「AI 提示生成失败」。对齐反代链上最短的
  // 那一环（NPM 的 proxy_read_timeout 60s），两边的心跳 / 空闲超时都在它之内。
  idleTimeout: 60,
  async fetch(request, bunServer) {
    const url = new URL(request.url)
    if (url.pathname.startsWith(`${config.avatarUriPrefix}/`)) {
      const hit = await serveUpload(url.pathname, config.avatarUriPrefix, config.avatarDirectory)
      if (hit) return hit
      if (basename(decodeURIComponent(url.pathname)) === 'default.png') {
        return new Response(DEFAULT_AVATAR_SVG, {
          headers: {
            'content-type': 'image/svg+xml',
            'cache-control': 'public, max-age=3600',
          },
        })
      }
      return new Response('Not found', { status: 404 })
    }
    // 题面里插的图片。原来没有这一段 —— 后台上传成功、返回 /public/upload/xxx，
    // 但没有任何路由伺服它，题面图片一律 404。
    if (url.pathname.startsWith(`${config.uploadUriPrefix}/`)) {
      return (await serveUpload(url.pathname, config.uploadUriPrefix, config.uploadDirectory)) ?? new Response('Not found', { status: 404 })
    }
    if (url.pathname === '/ws/submissions' || url.pathname === '/ws/config' || url.pathname === '/ws/collab') {
      if (!isAllowedWebSocketOrigin(request.headers.get('origin'), url)) {
        return new Response('Forbidden', { status: 403 })
      }
      const session = await authenticateWebSocket(request)
      if (!session) return new Response('Unauthorized', { status: 401 })
      const { user } = session
      const kind = url.pathname === '/ws/config' ? 'config' : url.pathname === '/ws/collab' ? 'collab' : 'submissions'
      if (
        bunServer.upgrade(request, {
          // 前端是借子协议带 token 来的，不回一个它传过的子协议 Chrome 就判握手失败
          headers: { 'Sec-WebSocket-Protocol': WS_AUTH_PROTOCOL },
          data: {
            userId: user.id,
            kind,
            sid: session.sid,
            tokenVersion: session.tokenVersion,
            username: user.username,
            adminType: user.adminType,
          },
        })
      ) {
        return undefined
      }
      return new Response('WebSocket upgrade failed', { status: 400 })
    }
    return app.fetch(request)
  },
  websocket: submissionWebSocketHandler(),
})

await bridgeSubmissionEvents(server)
startSessionSweep()
console.log(`OJ2 API listening on http://localhost:${server.port}`)
// 迁移刚灌进来、或者上次没补完的挑战：拿历史上做对的代码补一遍谁已经做到了。
// 晚一点再跑，别和刚起来时涌进来的请求抢那两个核
setTimeout(() => void scanPendingChallenges(), 20_000)