import std.stdio, std.json, std.getopt;
import std.net.curl, std.conv: to;
import core.stdc.stdlib: exit;

void main(string[] args) {
    string serverName;
    try getopt(args, config.required, "server|s", "Matrix server domain", &serverName);
    catch (GetOptException e) {
        writeln(e.msg);
        exit(1);
    }

    CHECK:
    serverName = "https://"~serverName;
    auto resp = Request(serverName~"/_matrix/federation/v1/version");

    if (resp.status == 200) {
        JSONValue srv = parseJSON(resp.content)["server"];
        writefln("%s: %s", srv["name"].str(), srv["version"].str());
    } else {
        resp = Request(serverName~"/.well-known/matrix/server");
        if (resp.status != 200) {
            writeln("Coudn't find matrix server on this domain.");
            exit(1);
        }

        serverName = parseJSON(resp.content)["m.server"].str();
        goto CHECK;
    }     
}

struct Request {
    this(string url) {
        this.perform(url);
    }

    string content;
    string[string] headers;
    ushort status;

    void perform(string url) {
        auto request = HTTP(url);
        try {
            request.onReceive = (ubyte[] data) {
                foreach (s; data)
                    Request.content ~= to!char(s);
                return data.length;
            };
            request.perform();
            Request.headers = request.responseHeaders();
            Request.status = request.statusLine().code;
        } catch (CurlException e) {
            writeln(e.msg);
            exit(1);
        }
    }
}