// ==========================================================================
// ============ see plot_callisto function at the end of the file ===========
// ==========================================================================
int HandleInput()
{
    // This is a pure man's command line interface to wait for a key input
    // and allow exit but at the same time allow interaction with the GUI
    TTimer timer("gSystem->ProcessEvents();", 50, kFALSE);

    // While reading the input process gui events asynchronously
    timer.TurnOn();
    const char *gl = Getline("Type 'q' to exit, or event number and <return> to go on: ");
    timer.TurnOff();

    TString input = gl;
    if (input=="q\n" || input==".q\n")
        return kFALSE;

    return kTRUE;
}

// Create a histogram for the trace
TH1D hist("Trace", "Waveform", 1024, -0.25, 511.75);

// All 'data members' that are required globally
TCanvas *c;
MPedestalSubtractedEvt *fEvt = 0;

//
// Called like all PreProcess functions of tasks. Get the access to
// the containers necessary for you.
//
Int_t PreProcess(MParList *plist)
{
    fEvt = (MPedestalSubtractedEvt*)plist->FindObject("MPedestalSubtractedEvt");
    if (!fEvt)
    {
        gfLog << err << "MPedestalSubtractedEvt not found... aborting." << endl;
        return kALSE;
    }

    // Create a canvas and plot the histogram into it
    c = new TCanvas;
    hist.SetStats(kFALSE);
    hist.Draw();

    TF1 constant("zero", "[0]", -0.25, 511.75);
    constant.SetParameter(0, 0);
    constant.SetLineColor(kBlack);
    constant.SetLineStyle(kDashed);
    constant.DrawCopy("same");

    // One p.e.
    constant.SetParameter(0, 20);
    constant.SetLineStyle(kDotted);
    constant.DrawCopy("same");

    constant.SetParameter(0, -20);
    constant.DrawCopy("same");

    return kTRUE;
}

Int_t Process()
{
    int pixel_index = 0;

    // Number of samples per pixel (usually 1024)
    int numsamples = fEvt->GetNumSamples();
    Float_t *cal = fEvt->GetSamples(pixel_index);

    // reset contents of histogram and fill new contents
    hist.Reset();
    for (int i=0; i<numsamples; i++)
        hist.Fill(i*0.5, cal[i]); // Convert sample to nano-second

    // Reset min/max range
    hist.SetMinimum();
    hist.SetMaximum();

    // Set a reasonable range
    if (hist.GetMinimum()>-50)
        hist.SetMinimum(-50);
    if (hist.GetMaximum()<250)
        hist.SetMaximum(250);

    // Signal root to update the canvas/pad
    c->Modified();
    c->Update();

    bool rc = HandleInput();

    // wait for 'return'
    return rc;
}


/*****************************************************************

 This is an example how to access and display calibrated raw data

 datafile:
    A data file written by the fadctrl or ceres, e.g.
    20170727_006.fits.fz or
    00000015.003_D_MonteCarlo019_Events.fits.fz

 drsfile:
    Usually the third of the three .drs.fits files from a
    DRS calibration sequence, e.g. 20170727_004.drs.fits

 To run the macro from the command line (assuming you are in a directory
 Mars/build where you have built your Mars environment) ou can do

    root ../hawc/plot_trace.C\(\"20191002_018.fits.fz\",\"20191002_013.drs.fits\"\)

 or from within root

    [0] .x ../hawc/plot_trace.C("20191002_018.fits.fz", "20191002_013.drs.fits")

******************************************************************/
int plot_trace(const char *datafile, const char *drsfile)
{
    // ======================================================

    // true:  Display correctly mapped pixels in the camera displays
    //        but the value-vs-index plot is in software/spiral indices
    // false: Display pixels in hardware/linear indices,
    //        but the order is the camera display is distorted.
    //        false is assumed automatically for files with the ISMC flag set.
    bool usemap = true;

    // mapping file (found in Mars/hawc)
    const char *mmap = usemap ? "../hawc/FAMOUSmap171218.txt" : NULL;

    // ======================================================

    // Check if the requested mapping file is available
    if (mmap && gSystem->AccessPathName(mmap, kFileExists))
    {
        gLog << err << "ERROR - Cannot access mapping file '" << mmap << "'" << endl;
        return 11;
    }

    // -------------------------------------------------------

    // Check and read the DRS calibration constants
    MDrsCalibration drscalib300;
    if (drsfile && !drscalib300.ReadFits(drsfile))
        return 31;

    // -------------------------------------------------------

    // Setup camera geometry
    MGeomCamFAMOUS geom;

    // ======================================================

    // Setup task for reading the file
    MRawFitsRead read;
    read.LoadMap(mmap);
    read.AddFile(datafile);

    // Setup task which ensures sizes of containers consistent with camera geometry
    MGeomApply apply;

    // Setup task for DRS calibration
    MDrsCalibApply drsapply;
    drsapply.SetMaxNumPrevEvents(0); // Switched off step-correction -> crashes due to the requirement of N*9 ch

    // Setup intercative task calling the functions defined above
    MTaskInteractive mytask;
    mytask.SetPreProcess(PreProcess);
    mytask.SetProcess(Process);

    // ======================================================

    MTaskList tlist;

    MParList plist;
    plist.AddToList(&tlist);
    plist.AddToList(&drscalib300);
    plist.AddToList(&geom);

    // ------------------ Setup eventloop and run analysis ---------------

    tlist.AddToList(&read);
    tlist.AddToList(&apply);
    tlist.AddToList(&drsapply);
    tlist.AddToList(&mytask);

    // ------------------ Setup and run eventloop ---------------

    MEvtLoop loop(gSystem->BaseName(datafile));
    loop.SetParList(&plist);
 
    if (!loop.Eventloop())
        return 4;

    // Print statistics information about your loop
    tlist.PrintStatistics();

    return 0;
}