import fs from 'node:fs'
import path from 'node:path'
import { fileURLToPath } from 'node:url'
import cookie from '@fastify/cookie'
import multipart from '@fastify/multipart'
import fastifyStatic from '@fastify/static'
import Fastify, { type FastifyServerOptions } from 'fastify'
import type { ApiErrorBody } from '@agent-server/shared'
import type { App } from '../app'
import { config } from '../config'
import { AppError } from '../lib/errors'
import adminRoutes from './routes/admin'
import v1Routes from './routes/v1'
import { registerGateway } from '../mcp-gateway/server'

export async function buildServer(app: App, opts: { logger: FastifyServerOptions['loggerInstance'] }) {
  const f = Fastify({ loggerInstance: opts.logger, trustProxy: config.trustProxy, bodyLimit: 2 * 1048576 })

  await f.register(cookie)
  await f.register(multipart)

  f.setErrorHandler((err, req, reply) => {
    if (err instanceof AppError) {
      const body: ApiErrorBody = { error: { code: err.code, message: err.message, details: err.details } }
      return reply.code(err.status).send(body)
    }
    const status = (err as { statusCode?: number }).statusCode ?? 500
    if (status >= 500) req.log.error({ err }, 'unhandled error')
    const body: ApiErrorBody = { error: { code: status >= 500 ? 'internal_error' : 'bad_request', message: status >= 500 ? '服务器内部错误' : (err as Error).message } }
    return reply.code(status).send(body)
  })

  f.get('/healthz', async () => ({ ok: true }))
  f.get('/readyz', async () => {
    app.db.$client.prepare('select 1').get()
    return { ok: true, runs: app.runs.stats() }
  })

  await f.register(v1Routes, { prefix: '/v1', app })
  registerGateway(f, app.gatewayTokens)
  await f.register(adminRoutes, { prefix: '/admin/v1', app })

  // 生产环境由服务托管后台静态资源，同源访问
  // 源码运行时位于 src/http，打包后位于 dist，两种情况都向上寻找 apps/admin/dist
  const here = path.dirname(fileURLToPath(import.meta.url))
  const adminDist = config.adminDist
    ?? [path.resolve(here, '../../../admin/dist'), path.resolve(here, '../../admin/dist')].find(p => fs.existsSync(path.join(p, 'index.html')))
  if (adminDist && fs.existsSync(path.join(adminDist, 'index.html'))) {
    await f.register(fastifyStatic, { root: adminDist, prefix: '/admin/', wildcard: false })
    f.get('/admin/*', (_req, reply) => reply.sendFile('index.html'))
    f.get('/', (_req, reply) => reply.redirect('/admin/'))
  }

  return f
}