#include <docopt.h>
#include <tao/json.hpp>
#include <hoytech/protected_queue.h>
#include <hoytech/file_change_monitor.h>

#include "golpe.h"

#include "WriterPipeline.h"
#include "Subscription.h"
#include "WSConnection.h"
#include "events.h"
#include "PluginWritePolicy.h"


static const char USAGE[] =
R"(
    Usage:
      stream <url> [--dir=<dir>]

    Options:
      --dir=<dir>   Direction: down, up, or both [default: down]
)";



void cmd_stream(const std::vector<std::string> &subArgs) {
    std::map<std::string, docopt::value> args = docopt::docopt(USAGE, subArgs, true, "");

    std::string url = args["<url>"].asString();
    std::string dir = args["--dir"] ? args["--dir"].asString() : "down";

    if (dir != "up" && dir != "down" && dir != "both") throw herr("invalid direction: ", dir, ". Should be one of up/down/both");

    flat_hash_set<std::string> downloadedIds;
    WriterPipeline writer;
    WSConnection ws(url);
    Decompressor decomp;

    PluginWritePolicy writePolicy;


    ws.onConnect = [&]{
        if (dir == "down" || dir == "both") {
            auto encoded = tao::json::to_string(tao::json::value::array({ "REQ", "sub", tao::json::value({ { "limit", 0 } }) }));
            ws.send(encoded);
        }
    };

    ws.onMessage = [&](auto msg, uWS::OpCode, size_t){
        auto origJson = tao::json::from_string(msg);

        if (origJson.is_array()) {
            if (origJson.get_array().size() < 2) throw herr("array too short");

            auto &msgType = origJson.get_array().at(0);
            if (msgType == "EOSE") {
                return;
            } else if (msgType == "NOTICE") {
                LW << "NOTICE message: " << tao::json::to_string(origJson);
                return;
            } else if (msgType == "OK") {
                if (!origJson.get_array().at(2).get_boolean()) {
                    LW << "Event not written: " << origJson;
                }
            } else if (msgType == "EVENT") {
                if (dir == "down" || dir == "both") {
                    if (origJson.get_array().size() < 3) throw herr("array too short");
                    auto &evJson = origJson.at(2);

                    std::string okMsg;
                    auto res = writePolicy.acceptEvent(evJson, hoytech::curr_time_s(), EventSourceType::Stream, ws.remoteAddr, okMsg);
                    if (res == WritePolicyResult::Accept) {
                        downloadedIds.emplace(from_hex(evJson.at("id").get_string()));
                        writer.write({ std::move(evJson), EventSourceType::Stream, url });
                    } else {
                        LI << "[" << ws.remoteAddr << "] write policy blocked event " << evJson.at("id").get_string() << ": " << okMsg;
                    }
                } else {
                    LW << "Unexpected EVENT";
                }
            } else {
                throw herr("unexpected first element");
            }
        } else {
            throw herr("unexpected message");
        }
    };


    uint64_t currEventId;

    {
        auto txn = env.txn_ro();
        currEventId = getMostRecentLevId(txn);
    }

    ws.onTrigger = [&]{
        if (dir == "down") return;

        auto txn = env.txn_ro();

        env.foreach_Event(txn, [&](auto &ev){
            currEventId = ev.primaryKeyId;

            auto id = std::string(sv(ev.flat_nested()->id()));
            if (downloadedIds.find(id) != downloadedIds.end()) {
                downloadedIds.erase(id);
                return true;
            }

            std::string msg = std::string("[\"EVENT\",");
            msg += getEventJson(txn, decomp, ev.primaryKeyId);
            msg += "]";

            ws.send(msg);

            return true;
        }, false, currEventId + 1);
    };

    std::unique_ptr<hoytech::file_change_monitor> dbChangeWatcher;

    if (dir == "up" || dir == "both") {
        dbChangeWatcher = std::make_unique<hoytech::file_change_monitor>(dbDir + "/data.mdb");

        dbChangeWatcher->setDebounce(100);

        dbChangeWatcher->run([&](){
            ws.trigger();
        });
    }


    ws.run();
}