"""
legend - Plot a legend.
"""
from pygmt.clib import Session
from pygmt.exceptions import GMTInvalidInput
from pygmt.helpers import (
build_arg_list,
data_kind,
fmt_docstring,
is_nonstr_iter,
kwargs_to_strings,
use_alias,
)
@fmt_docstring
@use_alias(
R="region",
J="projection",
D="position",
F="box",
V="verbose",
c="panel",
p="perspective",
t="transparency",
)
@kwargs_to_strings(R="sequence", c="sequence_comma", p="sequence")
def legend(self, spec=None, position="JTR+jTR+o0.2c", box="+gwhite+p1p", **kwargs):
r"""
Plot legends on maps.
Makes legends that can be overlaid on maps. Reads specific
legend-related information from an input file, or automatically creates
legend entries from plotted symbols that have labels. Unless otherwise
noted, annotations will be made using the primary annotation font and
size in effect (i.e., :gmt-term:`FONT_ANNOT_PRIMARY`).
Full option list at :gmt-docs:`legend.html`
{aliases}
Parameters
----------
spec : None or str
Either ``None`` [Default] for using the automatically generated legend
specification file, or a *filename* pointing to the legend
specification file.
{projection}
{region}
position : str
[**g**\|\ **j**\|\ **J**\|\ **n**\|\ **x**]\ *refpoint*\
**+w**\ *width*\ [/*height*]\ [**+j**\ *justify*]\ [**+l**\ *spacing*]\
[**+o**\ *dx*\ [/*dy*]].
Define the reference point on the map for the
legend. By default, uses **JTR**\ **+jTR**\ **+o**\ 0.2c which
places the legend at the top-right corner inside the map frame, with a
0.2 cm offset.
box : bool or str
[**+c**\ *clearances*][**+g**\ *fill*][**+i**\ [[*gap*/]\ *pen*]]\
[**+p**\ [*pen*]][**+r**\ [*radius*]][**+s**\ [[*dx*/*dy*/][*shade*]]].
If set to ``True``, draw a rectangular border around the legend
using :gmt-term:`MAP_FRAME_PEN`. By default, uses
**+g**\ white\ **+p**\ 1p which draws a box around the legend using a
1p black pen and adds a white background.
{verbose}
{panel}
{perspective}
{transparency}
"""
kwargs = self._preprocess(**kwargs)
if kwargs.get("D") is None:
kwargs["D"] = position
if kwargs.get("F") is None:
kwargs["F"] = box
with Session() as lib:
if spec is None:
specfile = ""
elif data_kind(spec) == "file" and not is_nonstr_iter(spec):
# Is a file but not a list of files
specfile = spec
else:
raise GMTInvalidInput(f"Unrecognized data type: {type(spec)}")
lib.call_module(module="legend", args=build_arg_list(kwargs, infile=specfile))