# Tool to align the laser on the cathode.
# S. Bettoni, A. Gobbo, D. Voulot
# 06/06/2016

# Procedure:
    # switch off all the magnets between the gun solenoid and the screen or BPM used for the measurement
    # change the phase of the gun RF
    # look at the centroid position (BPM or screen) downstream of the gun.

phi_set = Channel("SINEG01-RSYS:SET-BEAM-PHASE")
phi_get = Channel("SINEG01-RSYS:GET-BEAM-PHASE")
# cam_x, cam_y = ...       # some camtool command / channel?
bpm_x = Channel("SINEG01-DBPM340:X1")
bpm_y = Channel("SINEG01-DBPM340:Y1")

def ccr(mag):
    n = 1
    while n > 0:
        sleep(0.5)
        n = caget(mag + ":I-COMP")
def laser_on():
    caput("SIN-CVME-TIMAST-TMA:LaserDelayControl", 0)
def laser_off():
    caput("SIN-CVME-TIMAST-TMA:LaserDelayControl", 1)

phi1 = 20.0
phi2 = 150.0
dphi = 1.0

# Switch off magnets
mag = [ "SINEG01-MCRX120","SINEG01-MCRY120",
        "SINEG01-MQUA140",
        "SINEG01-MQUA150",
        "SINEG01-MCRX160","SINEG01-MCRY160",
        "SINEG01-MCRX180","SINEG01-MCRY180",
        "SINEG01-MCRX200","SINEG01-MCRY200",
        "SINEG01-MCRX220","SINEG01-MCRY220",
        "SINEG01-MQUA310",
        "SINEG01-MQUA320" ]
for m in mag:
    caput(m + ":I-SET", 0.0)
for m in mag:
    ccr(m)

# Scan using the screen
#r = lscan(phi_set, [phi_get, cam_x, cam_y], phi1, phi2, dphi, 0.5)
# Scan using the BPM
r = lscan(phi_set, [phi_get, bpm_x, bpm_y], phi1, phi2, dphi, 0.5, before_read = laser_on(), after_read = laser_off())

# take the result of the scan and do the plots
plot(r.getReadable(2), xdata=r.getReadable(1), title = "Centroid excursion")

# save the entry in the logbook
msg = str(r)
msg = msg + "\nFile: " + get_context().path
msg = msg + "\n\n" + r.print()
elog("Gun solenoid current scan", msg , get_plot_snapshots())