#include <iostream>
#include <fstream>
#include <time.h>
#include <unistd.h>
#include <getopt.h>
#include <sstream>

#include <TROOT.h>
#include <TRint.h>
#include <TSystem.h>

#include "ICOMETLog.hxx"
#include "IRooTrackerHistogram.hxx"

void usage(void) {
    std::cout
    <<"Usage: oaRooTracker_AddHistograms.exe [options] files\n"
      "  where file specifier is the path to a list of oaRooTracker histogram files\n"
      "  <filepath>/<oaRooTrackerHistogramFile>\n"
      "The specified files are added into one new, large file. \n"
      "Options: \n"
      "    -I    Text file containing a list of input oaRooTracker histogram files.\n"
      "          Each line must match one of the following syntax. \n"
      "            <filepath>/<oaRooTrackerHistogramFile>\n"
      "    -o    Name of the output file\n"
      "    -b    Flag to allow bad files to be skipped\n" 
      "    -v    Print information about the adding process\n" 
      "    -f    Flag to skip checks for consistency before adding"
      "    -N    The total number of events the input files correspond to.\n"
      "            This changes the integral of the frequency histograms by changing\n"
      "            the number of events in the zero bin. total_events must be greater than\n"
      "            the total number of events in the input files\n"
      "            Ex: Input file has 20 events, 7 with protons.\n"
      "                Without total_events argument, the 0 bin is 13 for proton frequency\n"
      "                With total_events = 30, the 0 bin is 23 for proton frequency\n"
      "                With total_events = 19, error will be thrown\n" << std::endl;

}

int main(int argc, char **argv) {
    // Get the default options
    std::vector<std::string> inputFiles;
    std::string fOutFileName = "addedRTHists.root";
    bool skipBadFiles = false;
    bool skipCheck = false;
    bool printInfo=false;
    int totalEvents = -1;

    // Set the options
    int c;
    std::ifstream fileList;
    std::stringstream option;
    while ((c = getopt(argc, argv, "I:o:bfN:h")) != -1){
        if(optarg) option.str(optarg);
        switch (c){
            // List of files from an input file list
            case 'I':
                fileList.open(optarg);
                std::copy(std::istream_iterator<std::string>(fileList),
                          std::istream_iterator<std::string>(),
                          std::back_inserter(inputFiles));
                fileList.close();
                break;
            // Choose the output name
            case 'o':
                fOutFileName= optarg;
                break;
            // Allow bad files to be skipped
            case 'b':
                skipBadFiles = true;
                break;
            // Print information about the adding
            case 'v':
                printInfo = true;
                break;
            // Don't check the files at all
            case 'f':
                skipCheck = true;
                break;
            case 'N':
                {
                    option >> totalEvents;
                    if (totalEvents < 0){
                        COMETNamedError("AddRooTrackerHists",
                            "Total Event size " << totalEvents
                            << ", but must be non-negative!");
                        return 1;
                    }
                }break;
            // Print the help menu
            case 'h':
                usage();
                return 0;
            // Let getopt deal with the rest
            case '?':
                return 1;
            default:
                abort();
        }
    }

    // Prepare the input files
    for(int i = optind;i<argc; ++i) inputFiles.push_back(argv[i]);

    //Configure COMETLog levels from input config file
    TString configPath = "${PWD}/cometlog.config";
    gSystem->ExpandPathName(configPath);
    COMET::ICOMETLog::Configure(configPath.Data());

    // Open the output
    COMET::IOutputRooTrackerHistogram outHist =
         COMET::IOutputRooTrackerHistogram(fOutFileName.c_str());
    outHist.InitialiseForWriting();
    // Open up the input files
    COMET::IRooTrackerHistogram* toAdd = NULL;
    int nHistsAdded = 0;
    for (std::vector<std::string>::iterator inFile = inputFiles.begin();
                                            inFile != inputFiles.end();
                                            inFile++){
        // Profile the addition of the histograms
        if (printInfo){
            ProcInfo_t beginInfo;
            gSystem->GetProcInfo(&beginInfo);
            COMETLog("MEM: Resident = " << beginInfo.fMemResident << ", "
                     "Virtual  = " << beginInfo.fMemVirtual);
        }
        // Open the file to add
        toAdd = COMET::IRooTrackerHistogram::Open(*inFile);
        bool badFile = false;
        if (toAdd == NULL){
            COMETNamedError("IRooTrackerHistogram", "Cannot open file " <<
                            (*inFile) << " to add to summed file " <<
                            fOutFileName.c_str());
            badFile = true;
        } else {
            // Try to add it
            try {
                outHist.Add(*toAdd, 1.0, skipCheck);
            } catch (COMET::ECannotAddHistograms& ex) {
                COMETNamedError("IRooTrackerHistogram", "Cannot open file " <<
                        (*inFile) << " to add to summed file " <<
                        fOutFileName.c_str());
                badFile = true;
            }
        }
        if (badFile == false) nHistsAdded++;
        // Return an error if we do not skip bad files
        if (badFile) {
            if (!skipBadFiles) return 1;
            // Skip the rest of the code if we are skipping bad files
            COMETNamedLog("IRooTrackerHistogram", "Skipping bad file " <<
                    (*inFile));
        }
        // Remove this histogram
        delete toAdd;
    }
    // Check if total events has been set
    if (totalEvents > 0){
        int nEventsInHist = outHist.GetNumTotalEvents();
        if (totalEvents < nEventsInHist){
            COMETError("The total number of events in the histogram is less"
                       " than the requested total number" <<
                       "\n  The total number of events in the output histogram is "
                       << nEventsInHist << 
                       "\n  The input total number of requested events is "
                       << totalEvents << 
                       "\n  This is not guaranteed to work");
        }
        outHist.SetFreqTotalEvents(totalEvents);
    }
    // Close the merged file
    outHist.Write();
    outHist.Close();
    // Recored the number of events merged
    COMETLog("Number of HistogramsAdded : " << nHistsAdded);
    return 0;
}