r"""
Calibration against boreholes
=============================

An inverted resistivity model is only as good as its tie to ground truth.
:class:`~pycsamt.interp.ModelCalibrator` adjusts the model so its
resistivity-to-lithology mapping honours **borehole logs**, and reports how
much each station had to move. This example calibrates the synthetic section
against two boreholes and compares before and after.
"""

# %%
# Boreholes and the native model
# ------------------------------
# The two boreholes log the true four-unit sequence at 500 m and 1500 m.
# :class:`~pycsamt.interp.borehole.Borehole` holds a list of depth
# ``Interval`` s with lithology labels.

from _interp_data import demo_boreholes, demo_model

from pycsamt.interp import ModelCalibrator

# Use the before/after calibrated-model panel (1st figure) as the thumbnail.
# sphinx_gallery_thumbnail_number = 1

rm = demo_model()
boreholes = demo_boreholes()
for bh in boreholes:
    print(
        f"{bh.name} @ x={bh.x:.0f} m: "
        f"{', '.join(iv.lithology for iv in bh.intervals)}"
    )

# %%
# Calibrate
# ---------
# :meth:`ModelCalibrator.fit <pycsamt.interp.ModelCalibrator.fit>` compares
# each near-borehole sounding to the log and rescales the model's
# resistivity-lithology boundaries to match, returning a corrected
# :class:`~pycsamt.interp.ResistivityModel` via ``calibrated_model()``.

cal = ModelCalibrator(max_borehole_distance=800.0, verbose=False).fit(
    rm, boreholes
)
nm = cal.calibrated_model()
print("native method:", rm.method)
print("calibrated method:", nm.method)

# %%
# Before and after
# ----------------
# :class:`~pycsamt.interp.plot.PlotCalibratedModel` stacks the native model,
# the calibrated model, and their difference, with the borehole positions
# marked — so you can see exactly where and how much the calibration moved
# the resistivities.

from pycsamt.interp.plot import PlotCalibratedModel

PlotCalibratedModel(nm, rm).plot()

# %%
# **Reading it.** The difference panel is near-zero away from the boreholes
# and picks up where the model's unit boundaries were nudged to match the
# logs. On real data, large corrections concentrated near a borehole warn
# that the inversion mis-placed a boundary there — worth revisiting before
# the model feeds :doc:`hydro-geophysics <plot_4_hydro_geophysics>`.