import * as vm from "vm";
import { NewEvalMessage, TypedValue, EvalFailedMessage, EvalDoneMessage, ServerMessage } from "../proto";
import { SendableConnection } from "../common/connection";

export const evaluate = async (connection: SendableConnection, message: NewEvalMessage): Promise<void> => {
    const argStr: string[] = [];
    message.getArgsList().forEach((value) => {
        argStr.push(value);
    });
    const sendResp = (resp: any): void => {
        const evalDone = new EvalDoneMessage();
        evalDone.setId(message.getId());
        const tof = typeof resp;
        if (tof !== "undefined") {
            const tv = new TypedValue();
            let t: TypedValue.Type;
            switch (tof) {
                case "string":
                    t = TypedValue.Type.STRING;
                    break;
                case "boolean":
                    t = TypedValue.Type.BOOLEAN;
                    break;
                case "object":
                    t = TypedValue.Type.OBJECT;
                    break;
                case "number":
                    t = TypedValue.Type.NUMBER;
                    break;
                default:
                    sendErr(EvalFailedMessage.Reason.EXCEPTION, `unsupported response type ${tof}`);
                    return;
            }
            tv.setValue(tof === "string" ? resp : JSON.stringify(resp));
            tv.setType(t);
            evalDone.setResponse(tv);
        }

        const serverMsg = new ServerMessage();
        serverMsg.setEvalDone(evalDone);
        connection.send(serverMsg.serializeBinary());
    };
    const sendErr = (reason: EvalFailedMessage.Reason, msg: string): void => {
        const evalFailed = new EvalFailedMessage();
        evalFailed.setId(message.getId());
        evalFailed.setReason(reason);
        evalFailed.setMessage(msg);

        const serverMsg = new ServerMessage();
        serverMsg.setEvalFailed(evalFailed);
        connection.send(serverMsg.serializeBinary());
    };
    try {
        const value = vm.runInNewContext(`(${message.getFunction()})(${argStr.join(",")})`, { require, setTimeout }, {
            timeout: message.getTimeout() || 30000,
        });
        sendResp(await value);
    } catch (ex) {
        sendErr(EvalFailedMessage.Reason.EXCEPTION, ex.toString());
    }
};