import ROOT,math,argparse

def getGConst(charge,sigma):
    return charge/(g_sigma*ROOT.TMath.Sqrt(ROOT.TMath.Pi()))

def fillTuple(ptuple,sig,con,N=5000,binw=-1,swidth=10):
    gauss=ROOT.TF1('f','gaus')
    gauss.SetParameter(0,con)
    gauss.SetParameter(1,0)
    gauss.SetParameter(2,sig)
    i=0
    posarr=[]
    if binw==-2:
        N=int(2*swidth*sig)
        
    while i<N:
        if binw==-2:
            pos=int(i-swidth*sig)
        else:
            pos=ROOT.gRandom.Uniform(-swidth*sig,swidth*sig)

        if binw>0:
            pos=int(pos/binw)*binw

        if pos in posarr:
            continue

        posarr.append(pos)
        i+=1
        val=gauss.Eval(pos)
        ptuple.Fill(ROOT.Double(pos),ROOT.Double(val))

def fitRooFit(ptuple,opt=''):
    rooX=ROOT.RooRealVar('x','',0.,-10*g_sigma,10*g_sigma)
    rooA=ROOT.RooRealVar('amp','',0.)
    varset=ROOT.RooArgSet('varset')
    varset.add(rooX)
    varset.add(rooA)
    dataset=ROOT.RooDataSet('dataset','pointstuple',ptuple,varset,'','amp')
    
    fitMean=ROOT.RooRealVar('fitMean','',0.,-10*g_sigma,10*g_sigma)
    fitSigma=ROOT.RooRealVar('fitSigma','',g_sigma,-10*g_sigma,10*g_sigma)
    fitgauss=ROOT.RooGaussian("fitgauss",'roogauss',rooX,fitMean,fitSigma)
   
    result=fitgauss.fitTo(dataset,
                          ROOT.RooFit.SumW2Error(True),
                          ROOT.RooFit.Save())
    if opt.find('plot')!=-1:

        frame=rooX.frame(ROOT.RooFit.Title('title'))
        dataset.plotOn(frame,ROOT.RooFit.Binning(50))
        fitgauss.plotOn(frame,ROOT.RooFit.Range("Full"),ROOT.RooFit.LineStyle(ROOT.kDashed),ROOT.RooFit.LineColor(ROOT.kRed)) 
        frame.Draw()
    error=fitMean.getError()
    return error

def fitTGraph(ptuple,opt=''):
    for e in ptuple:
        print ptuple.x,ptuple.amp

parser=argparse.ArgumentParser(description='Mickey Mouse MC for error on Mean')
#parser.add_argument()


ROOT.gROOT.ProcessLine(".x rootlogon.C") 



charge=100
g_sigma=10
g_const=getGConst(charge,g_sigma)


pointstuple=ROOT.TNtuple('points','','x:amp')


fillTuple(pointstuple,g_sigma,g_const,100,-2)

canv=ROOT.TCanvas('roofitCanvas','RooFit')
fitRooFit(pointstuple,'plot')

fitTGraph(pointstuple)
u=raw_input('done?')