// TCP Echo Server — binds to 127.0.0.1:9000 and echoes back received data
import Std::Io::{PrintLine, PrintInt};
import Std::Net::{Net_Create, Net_SetReuse, Net_Bind, Net_Listen, Net_Accept, Net_Send, Net_Recv, Net_Close};
import Std::String::{String_Eq};

func Main() -> int {
    let fd: int = Net_Create();
    if fd < 0 {
        PrintLine("Failed to create socket");
        return 1;
    }

    if !Net_SetReuse(fd) {
        PrintLine("Warning: failed to set SO_REUSEADDR");
    }

    if Net_Bind(fd, "127.0.0.1", 9000) == false {
        PrintLine("Failed to bind");
        Net_Close(fd);
        return 1;
    }

    if Net_Listen(fd, 5) == false {
        PrintLine("Failed to listen");
        Net_Close(fd);
        return 1;
    }

    PrintLine("Echo server listening on 127.0.0.1:9000");

    let client: int = Net_Accept(fd);
    if client < 0 {
        PrintLine("Failed to accept");
        Net_Close(fd);
        return 1;
    }

    PrintLine("Client connected");

    var running: bool = true;
    while running {
        let msg: String = Net_Recv(client, 1024);
        if String_Eq(msg, "") {
            running = false;
        } else {
            PrintLine("Received:");
            PrintLine(msg);
            let sent: int = Net_Send(client, msg);
            if sent < 0 {
                PrintLine("Send failed");
                running = false;
            }
        }
    }

    Net_Close(client);
    Net_Close(fd);
    PrintLine("Server shut down");
    return 0;
}