tactility/Tactility/Source/service/webserver/McpSimulatorHandler.cpp

#ifndef ESP_PLATFORM

#include <Tactility/service/webserver/WebServerService.h>
#include <app/manager.h>
#include <app/start.h>
#include <cJSON.h>
#include <http/server.h>

#include <cstdlib>
#include <cstring>
#include <sstream>
#include <string>
#include <vector>

namespace tt::service::webserver {
namespace {
constexpr size_t JSON_BODY_LIMIT = 64 * 1024;

cJSON* makeError(const cJSON* id, int code, const char* message) {
    cJSON* response = cJSON_CreateObject();
    cJSON_AddStringToObject(response, "jsonrpc", "2.0");
    cJSON* error = cJSON_AddObjectToObject(response, "error");
    cJSON_AddNumberToObject(error, "code", code);
    cJSON_AddStringToObject(error, "message", message);
    if (id != nullptr) cJSON_AddItemToObject(response, "id", cJSON_Duplicate(id, true));
    else cJSON_AddNullToObject(response, "id");
    return response;
}

cJSON* makeTextResult(const cJSON* id, const char* text, bool isError = false) {
    cJSON* response = cJSON_CreateObject();
    cJSON_AddStringToObject(response, "jsonrpc", "2.0");
    cJSON* result = cJSON_AddObjectToObject(response, "result");
    cJSON* content = cJSON_AddArrayToObject(result, "content");
    cJSON* item = cJSON_CreateObject();
    cJSON_AddStringToObject(item, "type", "text");
    cJSON_AddStringToObject(item, "text", text);
    cJSON_AddItemToArray(content, item);
    if (isError) cJSON_AddBoolToObject(result, "isError", true);
    if (id != nullptr) cJSON_AddItemToObject(response, "id", cJSON_Duplicate(id, true));
    else cJSON_AddNullToObject(response, "id");
    return response;
}

cJSON* makeToolList(const cJSON* id) {
    cJSON* response = cJSON_CreateObject();
    cJSON_AddStringToObject(response, "jsonrpc", "2.0");
    cJSON* result = cJSON_AddObjectToObject(response, "result");
    cJSON* tools = cJSON_AddArrayToObject(result, "tools");

    cJSON* capabilities = cJSON_CreateObject();
    cJSON_AddStringToObject(capabilities, "name", "get_capabilities");
    cJSON_AddStringToObject(capabilities, "description", "Get the simulator platform and display capability information.");
    cJSON_AddItemToObject(capabilities, "inputSchema", cJSON_Parse("{\"type\":\"object\",\"properties\":{}}"));
    cJSON_AddItemToArray(tools, capabilities);

    cJSON* listApps = cJSON_CreateObject();
    cJSON_AddStringToObject(listApps, "name", "list_apps");
    cJSON_AddStringToObject(listApps, "description", "List apps available in the simulator.");
    cJSON_AddItemToObject(listApps, "inputSchema", cJSON_Parse("{\"type\":\"object\",\"properties\":{}}"));
    cJSON_AddItemToArray(tools, listApps);

    cJSON* runApp = cJSON_CreateObject();
    cJSON_AddStringToObject(runApp, "name", "run_app");
    cJSON_AddStringToObject(runApp, "description", "Launch an installed simulator app by its app ID.");
    cJSON_AddItemToObject(runApp, "inputSchema", cJSON_Parse("{\"type\":\"object\",\"properties\":{\"app_id\":{\"type\":\"string\"}},\"required\":[\"app_id\"]}"));
    cJSON_AddItemToArray(tools, runApp);

    if (id != nullptr) cJSON_AddItemToObject(response, "id", cJSON_Duplicate(id, true));
    else cJSON_AddNullToObject(response, "id");
    return response;
}

std::string listAppsJson() {
    std::vector<const AppManifest*> manifests;
    app_manager_for_each_manifest([](const AppManifest* manifest, void* context) {
        static_cast<std::vector<const AppManifest*>*>(context)->push_back(manifest);
    }, &manifests);

    cJSON* apps = cJSON_CreateArray();
    for (const AppManifest* manifest : manifests) {
        cJSON* app = cJSON_CreateObject();
        cJSON_AddStringToObject(app, "id", manifest->id);
        cJSON_AddStringToObject(app, "name", manifest->name);
        cJSON_AddItemToArray(apps, app);
    }
    char* text = cJSON_PrintUnformatted(apps);
    std::string output = text == nullptr ? "[]" : text;
    cJSON_free(text);
    cJSON_Delete(apps);
    return output;
}

cJSON* handleCall(const cJSON* id, const cJSON* params) {
    const cJSON* name = cJSON_GetObjectItemCaseSensitive(params, "name");
    const cJSON* args = cJSON_GetObjectItemCaseSensitive(params, "arguments");
    if (!cJSON_IsString(name) || (args != nullptr && !cJSON_IsObject(args))) {
        return makeError(id, -32602, "Invalid params");
    }

    if (strcmp(name->valuestring, "get_capabilities") == 0) {
        return makeTextResult(id, "{\"platform\":\"tactility-simulator\",\"mcp\":true}");
    }
    if (strcmp(name->valuestring, "list_apps") == 0) {
        const std::string apps = listAppsJson();
        return makeTextResult(id, apps.c_str());
    }
    if (strcmp(name->valuestring, "run_app") == 0) {
        const cJSON* appId = cJSON_GetObjectItemCaseSensitive(args, "app_id");
        if (!cJSON_IsString(appId) || appId->valuestring == nullptr || appId->valuestring[0] == '\0') {
            return makeError(id, -32602, "app_id is required");
        }
        AppManifest manifest{};
        if (app_manager_find_manifest(appId->valuestring, &manifest) != ERROR_NONE) {
            return makeTextResult(id, "app not found", true);
        }
        AppInstanceId instanceId = 0;
        const error_t result = app_start(appId->valuestring, 0, nullptr, &instanceId);
        if (result != ERROR_NONE) return makeTextResult(id, "app launch failed", true);
        return makeTextResult(id, "ok");
    }
    return makeError(id, -32602, "Unknown simulator MCP tool");
}

cJSON* handleRpc(const char* body) {
    cJSON* request = cJSON_Parse(body);
    if (request == nullptr) return makeError(nullptr, -32700, "Parse error");
    const cJSON* id = cJSON_GetObjectItemCaseSensitive(request, "id");
    const cJSON* version = cJSON_GetObjectItemCaseSensitive(request, "jsonrpc");
    const cJSON* method = cJSON_GetObjectItemCaseSensitive(request, "method");
    const cJSON* params = cJSON_GetObjectItemCaseSensitive(request, "params");

    cJSON* response = nullptr;
    if (!cJSON_IsObject(request) || !cJSON_IsString(version) || strcmp(version->valuestring, "2.0") != 0 || !cJSON_IsString(method)) {
        response = makeError(id, -32600, "Invalid Request");
    } else if (strcmp(method->valuestring, "tools/list") == 0) {
        response = makeToolList(id);
    } else if (strcmp(method->valuestring, "tools/call") == 0) {
        response = handleCall(id, params);
    } else {
        response = makeError(id, -32601, "Method not found");
    }
    cJSON_Delete(request);
    return response;
}
}

error_t WebServerService::handleApiMcp(HttpServerRequest* request, void*) {
    const uint64_t length = http_server_request_get_content_length(request);
    if (length == 0 || length > JSON_BODY_LIMIT) {
        http_server_request_send_error(request, 400, "Invalid Content-Length");
        return ERROR_INVALID_ARGUMENT;
    }
    std::string body(static_cast<size_t>(length), '\0');
    size_t received = 0;
    while (received < body.size()) {
        const int count = http_server_request_receive(request, body.data() + received, body.size() - received);
        if (count <= 0) {
            http_server_request_send_error(request, 400, "Incomplete request body");
            return ERROR_UNDEFINED;
        }
        received += static_cast<size_t>(count);
    }

    cJSON* response = handleRpc(body.c_str());
    char* text = cJSON_PrintUnformatted(response);
    cJSON_Delete(response);
    if (text == nullptr) {
        http_server_request_send_error(request, 500, "Serialization failed");
        return ERROR_RESOURCE;
    }
    http_server_request_set_content_type(request, "application/json");
    http_server_request_send_string(request, text);
    cJSON_free(text);
    return ERROR_NONE;
}
}

#endif // ESP_PLATFORM