/**
 * Copyright - See the COPYRIGHT that is included with this distribution.
 * pvxs is distributed subject to a Software License Agreement found
 * in file LICENSE that is included with this distribution.
 */

#include <iostream>
#include <list>
#include <atomic>

#include <cstring>

#include <epicsVersion.h>
#include <epicsGetopt.h>
#include <epicsThread.h>

#include <pvxs/client.h>
#include <pvxs/log.h>
#include "utilpvt.h"
#include "evhelper.h"

using namespace pvxs;

namespace {

DEFINE_LOGGER(app, "app");

void usage(const char* argv0)
{
    std::cerr<<"Usage: "<<argv0<<" <opts> [pvname ...]\n"
               "\n"
               "  -h        Show this message.\n"
               "  -V        Print version and exit.\n"
               "  -r <req>  pvRequest condition.\n"
               "  -v        Make more noise.\n"
               "  -d        Shorthand for $PVXS_LOG=\"pvxs.*=DEBUG\".  Make a lot of noise.\n"
               "  -# <cnt>  Maximum number of elements to print for each array field.\n"
               "            Set to zero 0 for unlimited.\n"
               "            Default: 20\n"
               "  -F <fmt>  Output format mode: delta, tree\n"
               ;
}

}

int main(int argc, char *argv[])
{
    try {
        logger_config_env(); // from $PVXS_LOG
        bool verbose = false;
        std::string request;
        Value::Fmt::format_t format = Value::Fmt::Delta;
        auto arrLimit = uint64_t(-1);

        {
            int opt;
            while ((opt = getopt(argc, argv, "hVvdr:#:F:")) != -1) {
                switch(opt) {
                case 'h':
                    usage(argv[0]);
                    return 0;
                case 'V':
                    std::cout<<version_str()<<"\n";
                    std::cout<<EPICS_VERSION_STRING<<"\n";
                    std::cout<<"libevent "<<event_get_version()<<"\n";
                    return 0;
                case 'v':
                    verbose = true;
                    logger_level_set("app", Level::Debug);
                    break;
                case 'd':
                    logger_level_set("pvxs.*", Level::Debug);
                    break;
                case 'r':
                    request = optarg;
                    break;
                case '#':
                    arrLimit = parseTo<uint64_t>(optarg);
                    break;
                case 'F':
                    if(std::strcmp(optarg, "tree")==0) {
                        format = Value::Fmt::Tree;
                    } else if(std::strcmp(optarg, "delta")==0) {
                        format = Value::Fmt::Delta;
                    } else {
                        std::cerr<<"Warning: ignoring unknown format '"<<optarg<<"'\n";
                    }
                    break;
                default:
                    usage(argv[0]);
                    std::cerr<<"\nUnknown argument: "<<char(opt)<<std::endl;
                    return 1;
                }
            }
        }

        auto ctxt(client::Context::fromEnv());

        if(verbose)
            std::cout<<"Effective config\n"<<ctxt.config();

        // space for every subscription and one more for SigInt
        MPMCFIFO<std::shared_ptr<client::Subscription>> workqueue(argc-optind+1);
        std::list<decltype (workqueue)::value_type> ops;

        int remaining = argc-optind;
        std::atomic<bool> interrupt{false};

        for(auto n : range(optind, argc)) {

            ops.push_back(ctxt.monitor(argv[n])
                          .pvRequest(request)
                          .maskConnected(false)
                          .maskDisconnected(false)
                          .event([&workqueue](client::Subscription& mon)
                            {
                                workqueue.push(mon.shared_from_this());
                            })
                          .exec());
        }

        // expedite search after starting all requests
        ctxt.hurryUp();

        SigInt sig([&interrupt, &workqueue]() {
            interrupt = true;
            workqueue.push(nullptr);
        });

        while(auto mon = workqueue.pop()) {
            if(remaining==0u || interrupt.load())
                break;
            auto& name = mon->name();

            try {
                auto update = mon->pop();
                if(!update) {
                    // event queue empty
                    log_info_printf(app, "%s POP empty\n", name.c_str());
                    continue;
                }
                log_info_printf(app, "%s POP empty\n", name.c_str());

                std::cout<<name<<"\n";
                Indented I(std::cout);
                std::cout<<update.format()
                           .format(format)
                           .arrayLimit(arrLimit);

            }catch(client::Finished& conn) {
                log_info_printf(app, "%s POP Finished\n", name.c_str());
                if(verbose)
                    std::cerr<<name.c_str()<<" Finished\n";
                remaining--;

            }catch(client::Connected& conn) {
                std::cerr<<name.c_str()<<" Connected to "<<conn.peerName<<"\n";
                if(app.test(Level::Debug)) {
                    client::SubscriptionStat stats;
                    mon->stats(stats);
                    std::cerr<<name.c_str()<<" queueSize="<<stats.limitQueue<<"\n";
                }

            }catch(client::Disconnect& conn) {
                std::cerr<<name.c_str()<<" Disconnected\n";

            }catch(std::exception& err) {
                std::cerr<<name.c_str()<<" Error "<<typeid (err).name()<<" : "<<err.what()<<"\n";
            }

             // this subscription queue is not empty, reschedule
            workqueue.push(std::move(mon));
        }

        if(remaining==0u) {
            return 0;

        } else {
            if(verbose && interrupt)
                std::cerr<<"Interrupted\n";
            return 2;
        }
    }catch(std::exception& e){
        std::cerr<<"Error: "<<e.what()<<"\n";
        return 1;
    }
}