from __future__ import print_function

from math import log10

from obspy.clients.arclink import Client
from obspy.core import UTCDateTime
from obspy.geodetics import gps2dist_azimuth


paz_wa = {'sensitivity': 2800, 'zeros': [0j], 'gain': 1,
          'poles': [-6.2832 - 4.7124j, -6.2832 + 4.7124j]}

client = Client(user="sed-workshop@obspy.org")
t = UTCDateTime("2012-04-03T02:45:03")
st = client.get_waveforms("CH", "LKBD", "", "EH*", t - 300, t + 300,
                          metadata=True)

st.simulate(paz_remove="self", paz_simulate=paz_wa, water_level=10)
st.trim(t, t + 50)

tr_n = st.select(component="N")[0]
ampl_n = max(abs(tr_n.data))
tr_e = st.select(component="E")[0]
ampl_e = max(abs(tr_e.data))
ampl = max(ampl_n, ampl_e)

sta_lat = 46.38703
sta_lon = 7.62714
event_lat = 46.218
event_lon = 7.706

epi_dist, az, baz = gps2dist_azimuth(event_lat, event_lon, sta_lat, sta_lon)
epi_dist = epi_dist / 1000

a = 0.018
b = 2.17
ml = log10(ampl * 1000) + a * epi_dist + b
print(ml)
