"""
Calendar-aware datetime series
==============================

Plot cftime datetimes with UltraPlot's automatic locators and formatters.

Why UltraPlot here?
-------------------
UltraPlot includes CFTime converters and locators so climate calendars plot
cleanly without manual conversions. This is a common pain point in Matplotlib.

Key functions: :py:class:`ultraplot.ticker.AutoCFDatetimeLocator`, :py:class:`ultraplot.ticker.AutoCFDatetimeFormatter`.

See also
--------
* :doc:`Cartesian plots </cartesian>`
"""

import cftime
import matplotlib.units as munits
import numpy as np

import ultraplot as uplt

dates = [
    cftime.DatetimeNoLeap(2000 + i // 12, (i % 12) + 1, 1, calendar="noleap")
    for i in range(18)
]
values = np.cumsum(np.random.default_rng(5).normal(0.0, 0.6, len(dates)))

date_type = type(dates[0])
if date_type not in munits.registry:
    munits.registry[date_type] = uplt.ticker.CFTimeConverter()

fig, ax = uplt.subplots(refwidth=3.6)
ax.plot(dates, values, lw=2, marker="o")

locator = uplt.ticker.AutoCFDatetimeLocator(calendar="noleap")
formatter = uplt.ticker.AutoCFDatetimeFormatter(locator, calendar="noleap")
ax.xaxis.set_major_locator(locator)
ax.xaxis.set_major_formatter(formatter)

ax.format(
    xlabel="Simulation time",
    ylabel="Anomaly (a.u.)",
    title="No-leap calendar time series",
    xrotation=25,
)

fig.show()