// SPDX-FileCopyrightText: 2024 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only

#include <getopt.h>
#include <filesystem>
#include <csignal>
#include <sys/wait.h>
#include "../common/Logger.h"
#include "StreamWriter.h"
#include "../common/print_license.h"
#include "../image_puller/ZMQImagePuller.h"
#include "../image_puller/TCPImagePuller.h"

static Logger logger("jfjoch_writer");

static StreamWriter *writer;
static std::atomic<bool> quitok = false;

void print_usage() {
    logger.Info("Usage ./jfjoch_writer {options} <address of the ZeroMQ data source>");
    logger.Info("");
    logger.Info("Available options:");
    logger.Info("-T      | --tcp                      Use raw TCP/IP instead of ZeroMQ");
    logger.Info("-j<int> | --nproc=<int>              Number of forks (only with -T)");
    logger.Info("-d<int> | --root_dir=<int>           Root directory for file writing");
    logger.Info("-r<int> | --zmq_repub_port=<int>     ZeroMQ port for PUSH socket to republish images");
    logger.Info("-f<int> | --zmq_file_port=<int>      ZeroMQ port for PUB socket to inform about finalized files");
    logger.Info("-w<int> | --rcv_watermark=<int>      Receiving ZeroMQ socket watermark (default = 100)");
    logger.Info("-W<int> | --repub_watermark=<int>    Republish ZeroMQ socket watermark (default = 1000)");
    logger.Info("-v      | --verbose                  Verbose output");
    logger.Info("");
}

static void sigHandler (int sig){
    switch(sig){
        case SIGINT:
        case SIGQUIT:
        case SIGTERM:
        case SIGHUP:
        default:
            quitok = true;
            if (writer != nullptr)
                writer->Cancel();
            break;
    }
}

static void setUpUnixSignals(std::vector<int> quitSignals) {
    sigset_t blocking_mask;
    sigemptyset(&blocking_mask);
    for (auto sig : quitSignals)
        sigaddset(&blocking_mask, sig);

    struct sigaction sa;
    sa.sa_handler = sigHandler;
    sa.sa_mask    = blocking_mask;
    sa.sa_flags   = 0;

    for (auto sig : quitSignals)
        sigaction(sig, &sa, nullptr);
}

int main(int argc, char **argv) {
    RegisterHDF5Filter();

    print_license("jfjoch_writer");

    int32_t zmq_repub_port = -1;
    int32_t zmq_file_port = -1;
    int32_t nforks = 1;
    std::string root_dir = "";
    std::optional<int32_t> rcv_watermark;
    std::optional<int32_t> repub_watermark;
    bool verbose = false;

    static struct option long_options[] = {
            {"root_dir", required_argument, 0, 'd'},
            {"http_port", required_argument, 0, 'H'},
            {"zmq_repub_port", required_argument, 0, 'r'},
            {"zmq_file_port", required_argument, 0, 'f'},
            {"rcv_watermark", required_argument, 0, 'w'},
            {"repub_watermark", required_argument, 0, 'W'},
            {"verbose", required_argument, 0, 'v'},
            {"tcp", no_argument, 0, 'T'},
            {"nproc", required_argument, 0, 'j'},
            {0, 0, 0, 0}
    };

    int option_index = 0;
    int opt;
    bool raw_tcp = false;
    while ((opt = getopt_long(argc, argv, "?hH:r:f:R:d:W:w:vTj:",long_options, &option_index)) != -1 ) {
        switch (opt) {
            case 'j':
                nforks = atoi(optarg);
                if (nforks <= 0) {
                    logger.Error("-j must be a positive integer");
                    exit(EXIT_FAILURE);
                }
                break;
            case 'T':
                raw_tcp = true;
                break;
            case 'v':
                verbose = true;
                break;
            case 'H':
                // For back compatibility
                logger.Error("HTTP port option is deprecated");
                break;
            case 'r':
                zmq_repub_port = atoi(optarg);
                break;
            case 'w':
                rcv_watermark = atoi(optarg);
                if (rcv_watermark.value() <= 0) {
                    std::cerr << "Watermark must be positive number" << std::endl;
                    exit(EXIT_FAILURE);
                }
                break;
            case 'W':
                repub_watermark = atoi(optarg);
                if (repub_watermark.value() <= 0) {
                    std::cerr << "Watermark must be positive number" << std::endl;
                    exit(EXIT_FAILURE);
                }
                break;
            case 'f':
                zmq_file_port = atoi(optarg);
                break;
            case 'R': // back compatibility
                logger.Warning("-R option is deprecated; use -d");
            case 'd':
                root_dir = std::string(optarg);
                break;
            case '?':
            case 'h':
                print_usage();
                exit(EXIT_SUCCESS);
            default:
                print_usage();
                exit(EXIT_FAILURE);
        }
    }

    int first_argc = optind;

    if ((argc - first_argc != 1)) {
        print_usage();
        exit(EXIT_FAILURE);
    }

    if (nforks > 1 && !raw_tcp) {
        logger.Error("-j option is only compatible with -T (raw TCP)");
        exit(EXIT_FAILURE);
    }

    if (!root_dir.empty()) {
        try {
            std::filesystem::current_path(root_dir);
        } catch (const std::filesystem::filesystem_error &e) {
            logger.Error("Cannot change path to {}: {}", root_dir, e.what());
            exit(EXIT_FAILURE);
        }
    }
    logger.Info("Current path {}", std::filesystem::current_path().string());

    std::string repub_zmq_addr, file_done_zmq_addr;

    if ((zmq_file_port < UINT16_MAX) && (zmq_file_port > 0)) {
        file_done_zmq_addr = fmt::format("tcp://0.0.0.0:{:d}", zmq_file_port);
        logger.Info("Information on closed files is published via ZeroMQ PUB socket {:s}", file_done_zmq_addr);
    }

    if ((zmq_repub_port < UINT16_MAX) && (zmq_repub_port > 0)) {
        if (raw_tcp) {
            logger.Error("TCP republishing not supported at the moment");
            exit(EXIT_FAILURE);
        }
        repub_zmq_addr = fmt::format("tcp://0.0.0.0:{:d}", zmq_repub_port);
        logger.Info("Images are republished via ZeroMQ PUSH socket {:s}", repub_zmq_addr);
    }

    std::vector<pid_t> children;
    if (nforks > 1) {
        if (setpgid(0, 0) != 0) {
            logger.Warning("Failed to create dedicated process group; group shutdown may be less reliable");
        }

        for (int i = 0; i < nforks; i++) {
            pid_t pid = fork();
            if (pid == 0) {
                // Child: continue to normal writer initialization.
                children.clear();
                break;
            } else if (pid < 0) {
                logger.Error("Cannot fork child {}", i);
                for (pid_t cpid : children) {
                    kill(cpid, SIGTERM);
                }
                for (pid_t cpid : children) {
                    waitpid(cpid, nullptr, 0);
                }
                exit(EXIT_FAILURE);
            } else {
                children.push_back(pid);
            }
        }

        if (!children.empty()) {
            // Parent manager process only.
            std::vector<int> sigs{SIGQUIT, SIGINT, SIGTERM, SIGHUP};
            setUpUnixSignals(sigs);

            while (!quitok)
                pause();

            for (pid_t cpid : children) {
                kill(cpid, SIGTERM);
            }
            for (pid_t cpid : children) {
                waitpid(cpid, nullptr, 0);
            }
            exit(EXIT_SUCCESS);
        }
    }

    ZMQContext context;

    std::unique_ptr<ImagePuller> puller;
    if (raw_tcp)
        puller = std::make_unique<TCPImagePuller>(argv[first_argc], std::nullopt, repub_zmq_addr, repub_watermark);
    else
        puller = std::make_unique<ZMQImagePuller>(argv[first_argc], repub_zmq_addr, rcv_watermark, repub_watermark);


    writer = new StreamWriter(logger,*puller,file_done_zmq_addr, verbose);

    std::vector<int> sigs{SIGQUIT, SIGINT, SIGTERM, SIGHUP};
    setUpUnixSignals(sigs);

    while (!quitok)
        writer->Run();

    exit(EXIT_SUCCESS);
}