slits = ['Primaries horizontal','Primaries Vertical',
         'ExpBox Tert. horizontal ','ExpBox Tert. vertical',
         'ExpBox Quart. horizontal','ExpBox Quart. vertical']
              
ev = get_string('Please select slits', None, slits)
if ev is None: 
    raise Exception("Aborted")
    
elif ev == slits[0]: #Primaries-Horizontal after collimating mirror and before mono
        mmot = phs # slit size
        smot = phc  # slit centre
        r = 10.0     # scan half range 
        pclose = r/10. # slit size for scan
        popen = 12.0 # slit size in open position
        detector = mono_beam
        #MESSAGE,'Not ready yet',/cont
elif ev == slits[0]: #Primaries-Vertical before collimating mirror
        mmot = pvs
        smot = pvc
        r = 2.0
        pclose = r/10.
        popen = 2.0
        detector = mono_beam
        #MESSAGE,'Not ready yet',/cont
elif ev == slits[2]: #Exposure box Tertiary slits-Horizontal before IO
        mmot = ths
        smot =  thc
        r = 1.0 
        pclose = r/10.0
        popen = 1.0
        detector = Channel('X06DA-ES-BM:I0', 'd')
elif ev == slits[0]:    #Exposure box Tertiary slits-Vertical
        mmot = tvs
        smot = tvc
        r = 0.4
        pclose = r/4.
        popen = .4
        detector = Channel('X06DA-ES-BM:I0', 'd')
elif ev == slits[0]: #Exposure box Quartenary slits-Horizontal after I0
        mmot = qhs
        smot = qhc
        r = 0.4
        pclose = r/8.
        popen = .40 
        detector = marcover
        #MESSAGE,'To make sure the diode is connected',/cont
elif ev == slits[5]: #Exposure box Quartenary slits-Vertical
        mmot = qvs
        smot = qvc
        r = 0.3 
        pclose = r/6.
        popen = .20
        detector = mono_beam
        #MESSAGE,'To make sure the diode is connected',/cont

mmot.write(pclose)
result = lscan(smot, detector, -r,r, 20, latency = 0.5, relative = True) #SCAN,smot,-r,r,20,data=d,gfit=a,time=.5,detec=detector
(ydata, xdata) = (result.getReadable(0), result.getPositions(0))

ydata = [x*1e6 for x in ydata] 
maxy = max(ydata) #MAX(y,im)
cen =sum([ydata[i] * xdata[i] for i in range(len(ydata))]) / sum(ydata)  #TOTAL(x*y) / TOTAL(y) #TODO: is right? 



#OPLOT,x,GAUSSFIT(x,y,a,ESTIMATES = [maxy,cen,pclose,0,0,0],nterms=6)*1e-6, color=240,psym=6
(n, m, s) = fit(ydata, xdata)

#help,mmot
mmot.write(popen)

if abs(m) < 1 and abs(m-cen) < 0.5: #TODO: is a(1) the mean?
    print 'moving centre of slits to: ', m
    smot.mov(m)
else:
    #PLOTS,cen,[0,maxy]*1e6,color=240,linestyle=1 : #TODO ?
    msg='fit failed - do you want to drive to centre of mass position: '+ cen +' ?'
    if get_option(msg, 'YesNo') == 'Yes':    
        smot.mov(cen)