#pragma once
#include <functional>
#include <map>
#include <nlohmann/json.hpp>
#include <string>

namespace whetstone {

class DAPProxyServer {
public:
    using Handler = std::function<nlohmann::json(const nlohmann::json& args)>;

    DAPProxyServer() {
        auto empty = [](const nlohmann::json&) -> nlohmann::json { return nlohmann::json::object(); };
        for (const auto& cmd : {"initialize","launch","attach","setBreakpoints",
                                "stackTrace","scopes","variables","continue",
                                "next","stepIn","stepOut","disconnect"})
            handlers_[cmd] = empty;
    }

    nlohmann::json handle(const nlohmann::json& msg) {
        if (!msg.contains("type")) return {};

        std::string type = msg["type"].get<std::string>();

        // Events: no response
        if (type == "event") return {};

        // Requests
        if (type == "request") {
            std::string command = msg.value("command", "");
            int reqSeq = msg.value("seq", 0);
            nlohmann::json args = msg.contains("arguments") ? msg["arguments"]
                                                            : nlohmann::json::object();
            nlohmann::json body = nlohmann::json::object();
            auto it = handlers_.find(command);
            if (it != handlers_.end()) body = it->second(args);

            return {
                {"seq",         ++seq_},
                {"type",        "response"},
                {"request_seq", reqSeq},
                {"command",     command},
                {"success",     true},
                {"body",        body}
            };
        }

        return {};
    }

    void registerHandler(const std::string& command, Handler h) {
        handlers_[command] = std::move(h);
    }

private:
    std::map<std::string, Handler> handlers_;
    int seq_ = 0;
};

} // namespace whetstone