import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js'
import { z } from 'zod'
import { getSession, updateSession } from '../state.js'
import { broadcastToSession } from '../websocket.js'
/**
* 更新单个元素的属性
*/
export function registerUpdateElement(server: McpServer): void {
server.registerTool(
'update_element',
{
description:
'Update attributes of an existing element.\n\n' +
'Updatable attributes:\n' +
'- x, y: Position coordinates\n' +
'- width, height: Dimensions\n' +
'- strokeColor: Stroke color\n' +
'- backgroundColor: Background color\n' +
'- fillStyle: Fill style\n' +
'- strokeWidth: Stroke width\n' +
'- roughness: Roughness\n' +
'- opacity: Opacity\n' +
'- text: Text content (only for text type)\n\n' +
'Multi-session support: Specify sessionId to target a specific session.',
inputSchema: z.object({
sessionId: z
.string()
.optional()
.describe('Session ID. If not provided, uses default session.'),
id: z.string().describe('Element ID to update'),
updates: z
.object({
x: z.number().optional(),
y: z.number().optional(),
width: z.number().optional(),
height: z.number().optional(),
strokeColor: z.string().optional(),
backgroundColor: z.string().optional(),
fillStyle: z.enum(['solid', 'hachure', 'cross-hatch']).optional(),
strokeWidth: z.number().optional(),
strokeStyle: z.enum(['solid', 'dashed', 'dotted']).optional(),
roughness: z.number().optional(),
opacity: z.number().optional(),
text: z.string().optional(),
label: z
.object({
text: z.string(),
fontSize: z.number().optional(),
fontFamily: z.number().optional(),
strokeColor: z.string().optional(),
textAlign: z.enum(['left', 'center', 'right']).optional(),
verticalAlign: z.enum(['top', 'middle', 'bottom']).optional(),
})
.optional(),
fontSize: z.number().optional(),
roundness: z
.object({
type: z.number(),
value: z.number().optional(),
})
.optional(),
points: z.array(z.array(z.number())).optional(),
startBinding: z
.object({
elementId: z.string(),
focus: z.number(),
gap: z.number(),
})
.optional(),
endBinding: z
.object({
elementId: z.string(),
focus: z.number(),
gap: z.number(),
})
.optional(),
})
.describe('Attributes to update'),
}),
},
async ({ sessionId, id, updates }) => {
try {
const session = getSession(sessionId)
const element = session.elements.find((el) => el.id === id)
if (!element) {
return {
content: [
{
type: 'text',
text: `❌ Element not found: ${id} (Session: ${session.id})`,
},
],
isError: true,
}
}
// Normalize text updates on non-text elements to bound label for better alignment.
const normalizedUpdates: Record<string, unknown> = { ...updates }
if (element.type !== 'text') {
const shapeText = typeof updates.text === 'string' ? updates.text : undefined
const incomingLabel =
updates.label && typeof updates.label === 'object'
? (updates.label as Record<string, unknown>)
: undefined
if (incomingLabel || shapeText) {
const prevLabel =
element.label && typeof element.label === 'object'
? (element.label as Record<string, unknown>)
: {}
const nextLabel: Record<string, unknown> = {
...prevLabel,
...(incomingLabel ?? {}),
}
if (shapeText) nextLabel.text = shapeText
nextLabel.textAlign = (nextLabel.textAlign as string | undefined) ?? 'center'
nextLabel.verticalAlign = (nextLabel.verticalAlign as string | undefined) ?? 'middle'
normalizedUpdates.label = nextLabel
delete normalizedUpdates.text
}
}
// 更新元素属性
Object.assign(element, normalizedUpdates)
element.updated = Date.now()
element.version = (element.version ?? 0) + 1
// 更新会话
updateSession(session)
// 广播到同一会话的浏览器
broadcastToSession(session.id, {
type: 'update',
elements: session.elements,
appState: session.appState,
})
return {
content: [
{
type: 'text',
text:
`✅ Element updated: ${id} (Session: ${session.id})\n\n` +
`Updated attributes: ${Object.keys(normalizedUpdates).join(', ')}`,
},
],
}
} catch (error) {
const message = error instanceof Error ? error.message : String(error)
return {
content: [{ type: 'text', text: `Error: ${message}` }],
isError: true,
}
}
},
)
}
