"""
Double Y-axes graph
===================

The ``frame`` parameter of the plotting methods of the :class:`pygmt.Figure`
class can control which axes should be plotted and optionally show annotations,
tick marks, and gridlines. By default, all 4 axes are plotted, along with
annotations and tick marks (denoted **W**, **S**, **E**, **N**). Lowercase
versions (**w**, **s**, **e**, **n**) can be used to denote to only plot the
axes with tick marks. We can also only plot the axes without annotations and
tick marks using **l** (left axis), **r** (right axis), **t** (top axis),
**b** (bottom axis). When ``frame`` is used to change the frame settings, any
axes that are not defined using one of these three options are not drawn.

To plot a double Y-axes graph using PyGMT, we need to plot at least two base
maps separately. The base maps should share the same projection parameter and
x-axis limits, but different y-axis limits.
"""

# %%
import numpy as np
import pygmt
from pygmt.params import Axis, Frame, Position

# Generate two sample Y-data from one common X-data
x = np.linspace(1.0, 9.0, num=9)
y1 = x
y2 = x**2 + 110

fig = pygmt.Figure()

# Plot the common X-axes
# The bottom axis (S) is plotted with annotations and tick marks
# The top axis (t) is plotted without annotations and tick marks
# The left and right axes are not drawn
fig.basemap(
    region=[0, 10, 0, 10],
    projection="X15c/15c",
    frame=Frame(axes="St", xaxis=Axis(annot=True, tick=True, label="x")),
)

# Plot the Y-axis for y1-data
# The left axis (W) is plotted with blue annotations, ticks, and label
with pygmt.config(
    MAP_FRAME_PEN="blue",
    MAP_TICK_PEN="blue",
    FONT_ANNOT_PRIMARY="blue",
    FONT_LABEL="blue",
):
    fig.basemap(frame=Frame(axes="W", yaxis=Axis(annot=True, tick=True, label="y1")))

# Plot the line for y1-data
fig.plot(x=x, y=y1, pen="1p,blue")
# Plot points for y1-data
fig.plot(x=x, y=y1, style="c0.2c", fill="blue", label="y1")

# Plot the Y-axis for y2-data
# The right axis (E) is plotted with red annotations, ticks, and label
with pygmt.config(
    MAP_FRAME_PEN="red",
    MAP_TICK_PEN="red",
    FONT_ANNOT_PRIMARY="red",
    FONT_LABEL="red",
):
    fig.basemap(
        region=[0, 10, 100, 200],
        frame=Frame(axes="E", yaxis=Axis(annot=True, tick=True, label="y2")),
    )
# Plot the line for y2-data
fig.plot(x=x, y=y2, pen="1p,red")
# Plot points for y2-data
fig.plot(x=x, y=y2, style="s0.28c", fill="red", label="y2")

# Create a legend in the Top Left (TL) corner of the plot with a 0.1-cm offset.
fig.legend(position=Position("TL", offset=0.1), box=True)

fig.show()