#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Wollastonite, 29Si (I=1/2)
^^^^^^^^^^^^^^^^^^^^^^^^^^

29Si (I=1/2) spinning sideband simulation.
"""
# %%
# Wollastonite is a high-temperature calcium-silicate,
# :math:`\beta−\text{Ca}_3\text{Si}_3\text{O}_9`, with three distinct
# :math:`^{29}\text{Si}` sites. The :math:`^{29}\text{Si}` tensor parameters
# were obtained from Hansen `et. al.` [#f1]_
import matplotlib as mpl
import matplotlib.pyplot as plt
import mrsimulator.signal_processing as sp
import mrsimulator.signal_processing.apodization as apo
from mrsimulator import Simulator, SpinSystem, Site
from mrsimulator.methods import BlochDecaySpectrum

# global plot configuration
mpl.rcParams["figure.figsize"] = [4.5, 3.0]
# sphinx_gallery_thumbnail_number = 2

# %%
# **Step 1:** Create the sites.
S29_1 = Site(
    isotope="29Si",
    isotropic_chemical_shift=-89.0,  # in ppm
    shielding_symmetric={"zeta": 59.8, "eta": 0.62},  # zeta in ppm
)
S29_2 = Site(
    isotope="29Si",
    isotropic_chemical_shift=-89.5,  # in ppm
    shielding_symmetric={"zeta": 52.1, "eta": 0.68},  # zeta in ppm
)
S29_3 = Site(
    isotope="29Si",
    isotropic_chemical_shift=-87.8,  # in ppm
    shielding_symmetric={"zeta": 69.4, "eta": 0.60},  # zeta in ppm
)

sites = [S29_1, S29_2, S29_3]  # all sites

# %%
# **Step 2:** Create the spin systems from these sites. Again, we create three
# single-site spin systems for better performance.
spin_systems = [SpinSystem(sites=[s]) for s in sites]

# %%
# **Step 3:** Create a Bloch decay spectrum method.
method = BlochDecaySpectrum(
    channels=["29Si"],
    magnetic_flux_density=14.1,  # in T
    rotor_frequency=1500,  # in Hz
    spectral_dimensions=[
        {
            "count": 2048,
            "spectral_width": 25000,  # in Hz
            "reference_offset": -10000,  # in Hz
            "label": r"$^{29}$Si resonances",
        }
    ],
)

# %%
# **Step 4:** Create the Simulator object and add the method and spin system objects.
sim = Simulator()
sim.spin_systems += spin_systems  # add the spin systems
sim.methods += [method]  # add the method

# %%
# **Step 5:** Simulate the spectrum.
sim.run()

# The plot of the simulation before signal processing.
ax = plt.subplot(projection="csdm")
ax.plot(sim.methods[0].simulation.real, color="black", linewidth=1)
ax.invert_xaxis()
plt.tight_layout()
plt.show()

# %%
# **Step 6:** Add post-simulation signal processing.
processor = sp.SignalProcessor(
    operations=[sp.IFFT(), apo.Exponential(FWHM="70 Hz"), sp.FFT()]
)
processed_data = processor.apply_operations(data=sim.methods[0].simulation)

# The plot of the simulation after signal processing.
ax = plt.subplot(projection="csdm")
ax.plot(processed_data.real, color="black", linewidth=1)
ax.invert_xaxis()
plt.tight_layout()
plt.show()

# %%
# .. [#f1] Hansen, M. R., Jakobsen, H. J., Skibsted, J., :math:`^{29}\text{Si}`
#       Chemical Shift Anisotropies in Calcium Silicates from High-Field
#       :math:`^{29}\text{Si}` MAS NMR Spectroscopy, Inorg. Chem. 2003,
#       **42**, *7*, 2368-2377.
#       `DOI: 10.1021/ic020647f <https://doi.org/10.1021/ic020647f>`_