import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js'
import { z } from 'zod'
import { createSession, getSession, updateSession, deleteSession } from '../state.js'
import { broadcastToSession } from '../websocket.js'
import { log } from '../logger.js'
/**
* 创建新图表
* 支持创建新会话或清空现有会话
*/
export function registerCreateDiagram(server: McpServer): void {
server.registerTool(
'create_diagram',
{
description:
'Create a new diagram or clear an existing session.\n\n' +
'This action will:\n' +
'1. If a sessionId is specified, clear all elements in that session.\n' +
'2. If no sessionId is specified, create a new session.\n' +
'3. Reset the application state.\n\n' +
'Usage scenarios:\n' +
'• Starting a new project (no sessionId specified)\n' +
'• Clearing an existing diagram (sessionId specified)\n' +
'• Creating multiple independent diagrams (specify different sessionIds each time)',
inputSchema: z.object({
sessionId: z
.string()
.optional()
.describe(
'Session ID. If not specified, a new session is automatically generated. If an existing ID is specified, that session is cleared.',
),
viewBackgroundColor: z
.string()
.optional()
.describe('Canvas background color (default: #ffffff)'),
}),
},
async ({ sessionId, viewBackgroundColor }) => {
try {
let session
// 如果指定了 sessionId，尝试获取或创建
if (sessionId) {
// 先尝试获取现有会话，如果存在则清空
try {
session = getSession(sessionId, false) // 不自动创建
// 清空元素
session.elements = []
session.version++
} catch {
// 不存在，创建新的
session = createSession(sessionId)
}
} else {
// 创建全新会话
session = createSession()
}
// 设置背景颜色
if (viewBackgroundColor) {
session.appState.viewBackgroundColor = viewBackgroundColor
}
updateSession(session)
// 广播更新到同一会话的客户端
broadcastToSession(session.id, {
type: 'update',
elements: session.elements,
appState: session.appState,
})
log.info(`Created/reset diagram, session: ${session.id}`)
return {
content: [
{
type: 'text',
text:
`✅ Diagram created/reset!\n\n` +
`Session ID: ${session.id}\n` +
`Background Color: ${session.appState.viewBackgroundColor}\n` +
`Element Count: ${session.elements.length}\n\n` +
`You can use the add_elements tool to add elements (remember to pass sessionId: "${session.id}").`,
},
],
}
} catch (error) {
const message = error instanceof Error ? error.message : String(error)
return {
content: [{ type: 'text', text: `Error: ${message}` }],
isError: true,
}
}
},
)
// 注册删除会话的工具
server.registerTool(
'delete_diagram',
{
description:
'Delete the specified diagram session.\n\n' +
'Note: This will completely delete the session and all its elements, and cannot be undone.\n' +
'If you only want to clear elements but keep the session, use create_diagram and specify the sessionId.',
inputSchema: z.object({
sessionId: z.string().describe('The Session ID to delete'),
}),
},
async ({ sessionId }) => {
try {
const deleted = deleteSession(sessionId)
if (!deleted) {
return {
content: [
{
type: 'text',
text: `❌ Session not found: ${sessionId}`,
},
],
isError: true,
}
}
log.info(`Deleted session: ${sessionId}`)
return {
content: [
{
type: 'text',
text: `✅ Session deleted: ${sessionId}`,
},
],
}
} catch (error) {
const message = error instanceof Error ? error.message : String(error)
return {
content: [{ type: 'text', text: `Error: ${message}` }],
isError: true,
}
}
},
)
}
