import {
	SubscribeRequestSchema,
	UnsubscribeRequestSchema,
} from '@modelcontextprotocol/sdk/types.js'

const petSubscriptions = new Set<string>()

// NOTE: the server.server is how the MCP SDK exposes the underlying server
// instance for more advanced APIs like this one.

// Allow clients to subscribe to updates for a specific pet
server.server.setRequestHandler(SubscribeRequestSchema, async ({ params }) => {
	petSubscriptions.add(params.uri)
	return {} // no specific response data is needed
})

// Allow clients to unsubscribe from updates
server.server.setRequestHandler(
	UnsubscribeRequestSchema,
	async ({ params }) => {
		petSubscriptions.delete(params.uri)
		return {} // no specific response data is needed
	},
)

// When a pet's status changes, notify subscribed clients
function onPetStatusChange(petId: string, newStatus: string) {
	const uri = `pethotel://pets/${petId}`
	if (petSubscriptions.has(uri)) {
		server.server.notification({
			method: 'notifications/resources/updated',
			params: { uri, title: `Pet ${petId} status updated to ${newStatus}` },
		})
	}
}