kotlin-sdk/samples/kotlin-mcp-server/src/commonMain/kotlin/server.kt

package shared

import io.ktor.http.HttpStatusCode
import io.ktor.server.application.install
import io.ktor.server.cio.CIO
import io.ktor.server.engine.embeddedServer
import io.ktor.server.response.respond
import io.ktor.server.routing.post
import io.ktor.server.routing.routing
import io.ktor.server.sse.SSE
import io.ktor.server.sse.sse
import io.ktor.util.collections.ConcurrentMap
import io.modelcontextprotocol.kotlin.sdk.CallToolResult
import io.modelcontextprotocol.kotlin.sdk.GetPromptResult
import io.modelcontextprotocol.kotlin.sdk.Implementation
import io.modelcontextprotocol.kotlin.sdk.PromptArgument
import io.modelcontextprotocol.kotlin.sdk.PromptMessage
import io.modelcontextprotocol.kotlin.sdk.ReadResourceResult
import io.modelcontextprotocol.kotlin.sdk.Role
import io.modelcontextprotocol.kotlin.sdk.ServerCapabilities
import io.modelcontextprotocol.kotlin.sdk.TextContent
import io.modelcontextprotocol.kotlin.sdk.TextResourceContents
import io.modelcontextprotocol.kotlin.sdk.Tool
import io.modelcontextprotocol.kotlin.sdk.server.Server
import io.modelcontextprotocol.kotlin.sdk.server.ServerOptions
import io.modelcontextprotocol.kotlin.sdk.server.SseServerTransport
import io.modelcontextprotocol.kotlin.sdk.server.mcp

fun configureServer(): Server {
    val server = Server(
        Implementation(
            name = "mcp-kotlin test server",
            version = "0.1.0",
        ),
        ServerOptions(
            capabilities = ServerCapabilities(
                prompts = ServerCapabilities.Prompts(listChanged = true),
                resources = ServerCapabilities.Resources(subscribe = true, listChanged = true),
                tools = ServerCapabilities.Tools(listChanged = true),
            ),
        ),
    )

    server.addPrompt(
        name = "Kotlin Developer",
        description = "Develop small kotlin applications",
        arguments = listOf(
            PromptArgument(
                name = "Project Name",
                description = "Project name for the new project",
                required = true,
            ),
        ),
    ) { request ->
        GetPromptResult(
            "Description for ${request.name}",
            messages = listOf(
                PromptMessage(
                    role = Role.user,
                    content = TextContent(
                        "Develop a kotlin project named <name>${request.arguments?.get("Project Name")}</name>",
                    ),
                ),
            ),
        )
    }

    // Add a tool
    server.addTool(
        name = "kotlin-sdk-tool",
        description = "A test tool",
        inputSchema = Tool.Input(),
    ) { request ->
        CallToolResult(
            content = listOf(TextContent("Hello, world!")),
        )
    }

    // Add a resource
    server.addResource(
        uri = "https://search.com/",
        name = "Web Search",
        description = "Web search engine",
        mimeType = "text/html",
    ) { request ->
        ReadResourceResult(
            contents = listOf(
                TextResourceContents("Placeholder content for ${request.uri}", request.uri, "text/html"),
            ),
        )
    }

    return server
}

suspend fun runSseMcpServerWithPlainConfiguration(port: Int) {
    val servers = ConcurrentMap<String, Server>()
    println("Starting sse server on port $port. ")
    println("Use inspector to connect to the http://localhost:$port/sse")

    embeddedServer(CIO, host = "0.0.0.0", port = port) {
        install(SSE)
        routing {
            sse("/sse") {
                val transport = SseServerTransport("/message", this)
                val server = configureServer()

                // For SSE, you can also add prompts/tools/resources if needed:
                // server.addTool(...), server.addPrompt(...), server.addResource(...)

                servers[transport.sessionId] = server

                server.onClose {
                    println("Server closed")
                    servers.remove(transport.sessionId)
                }

                server.connect(transport)
            }
            post("/message") {
                println("Received Message")
                val sessionId: String = call.request.queryParameters["sessionId"]!!
                val transport = servers[sessionId]?.transport as? SseServerTransport
                if (transport == null) {
                    call.respond(HttpStatusCode.NotFound, "Session not found")
                    return@post
                }

                transport.handlePostMessage(call)
            }
        }
    }.startSuspend(wait = true)
}

/**
 * Starts an SSE (Server Sent Events) MCP server using the Ktor framework and the specified port.
 *
 * The url can be accessed in the MCP inspector at [http://localhost:$port]
 *
 * @param port The port number on which the SSE MCP server will listen for client connections.
 * @return Unit This method does not return a value.
 */
suspend fun runSseMcpServerUsingKtorPlugin(port: Int) {
    println("Starting sse server on port $port")
    println("Use inspector to connect to the http://localhost:$port/sse")

    embeddedServer(CIO, host = "0.0.0.0", port = port) {
        mcp {
            return@mcp configureServer()
        }
    }.startSuspend(wait = true)
}