// MCP 服务 (Streamable HTTP, 无状态)
// 入口: POST/GET/DELETE /api/mcp
// 鉴权: Authorization: Bearer <个人 MCP Token>, 与用户绑定, 拥有该用户全部业务权限.
import { Router } from 'express'
import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js'
import { StreamableHTTPServerTransport } from '@modelcontextprotocol/sdk/server/streamableHttp.js'
import { authenticateMcpToken } from './auth.js'
import { registerTaskToolsGroup } from './tools/tasks.js'
import { registerChecklistTools } from './tools/checklists.js'
import { registerCheckinTools } from './tools/checkin.js'

const SERVER_INFO = { name: 'iboard', version: '0.2.1' }

export function buildMcpServer(ctx) {
  const server = new McpServer(SERVER_INFO, {
    instructions: [
      '本服务连接 iBoard 个人工作台, 当前 token 已绑定到具体用户。',
      '可查询、新建、修改、删除、排序项目 / 看板列 / 任务, 以及检查清单和打卡。',
      '所有写操作立即生效, 删除类操作不可恢复, 调用前请确认用户意图。',
      '任务状态: todo / doing / done; 看板列可通过 boundStatus 与状态联动。',
    ].join('\n'),
  })
  registerTaskToolsGroup(server, ctx)
  registerChecklistTools(server, ctx)
  registerCheckinTools(server, ctx)
  return server
}

const router = Router()

router.all('/', async (req, res) => {
  let auth
  try {
    auth = await authenticateMcpToken(req)
  } catch (e) {
    console.error('[mcp] token 校验失败:', e)
    return res.status(500).json({
      jsonrpc: '2.0',
      id: req.body?.id ?? null,
      error: { code: -32603, message: 'MCP 鉴权失败' },
    })
  }

  if (!auth) {
    res.set('WWW-Authenticate', 'Bearer realm="iboard-mcp"')
    return res.status(401).json({
      jsonrpc: '2.0',
      id: req.body?.id ?? null,
      error: {
        code: -32001,
        message: '未授权: 请在「我的 → AI 接入 (MCP)」创建 Token, 并使用 Authorization: Bearer <Token>',
      },
    })
  }

  const server = buildMcpServer({ userId: auth.userId, user: auth.user })
  const transport = new StreamableHTTPServerTransport({
    sessionIdGenerator: undefined,
    enableJsonResponse: true,
  })

  res.on('close', () => {
    transport.close().catch(() => {})
    server.close().catch(() => {})
  })

  try {
    await server.connect(transport)
    await transport.handleRequest(req, res, req.body)
  } catch (e) {
    console.error('[mcp] 请求处理失败:', e)
    if (!res.headersSent) {
      res.status(500).json({
        jsonrpc: '2.0',
        id: req.body?.id ?? null,
        error: { code: -32603, message: e?.message || 'MCP 处理失败' },
      })
    }
  }
})

export default router