#!/usr/bin/env python3

__doc__ = \
"""
Generate a figure showing why a single beacon does
not arrive at the same time at two antennas.
"""

import matplotlib.pyplot as plt
import numpy as np
import scipy.signal as sig

### Functions

def beacon_time_difference_setup_figure(
        ax, 
        loc_trans, loc_antenna1, loc_antenna2,
        trans_kwargs={}, ant_kwargs={}
):
    """
    """
    return t, ants 


def _annotate_width(
        ax, name,
        x1, x2, y1=None, y2=None,
        text_dx=(0,0),
        text_kw={}, arrow_kw={}
):
    """
    Annotate a width between two points, with both an arrow between
    the points, and a text between them.

    Parameters:
    -----------
    ax: Axes
     the Axes to plot on
    name: str
     text to put on top of the arrow
    x1: float or tuple
     (horizontal) location of the first point
    x2: float or tuple
     (horizontal) location of the first point
    y1: float
     vertical location of the first point
    y2: float
     vertical location of the first point

    """
    if hasattr(x1, '__len__'):
        if y1 is None:
            y1 = x1[1]
        x1 = x1[0]

    if hasattr(x2, '__len__'):
        if y2 is None:
            y2 = x2[1]
        x2 = x2[0]

    y1 = 0 if y1 is None else y1
    y2 = y1 if y2 is None else y2

    default_arrow_kw = dict(
            xy = (x1, y1),
            xytext = (x2,y2),
            arrowprops = dict(
                arrowstyle="<->",
                shrinkA=False,
                shrinkB=False
            ),
    )

    default_text_kw = dict(
            va='bottom',
            ha='center',
            xy=((x1+x2)/2 + text_dx[0], (y1+y2)/2 + text_dx[1])
    )

    an1 = ax.annotate("", **{**default_arrow_kw, **arrow_kw})
    an2 = ax.annotate(name, **{**default_text_kw, **text_kw})

    return [an1, an2]


## Main
def main():
    """
    """

    trans_kwargs = {
            'zorder': 4,
            }
    ant_kwargs = {
            'zorder': 4,
            }
    annot_kwargs = {
            }
 
    trans_loc = [-0.9, 0]
    ant1_loc = [0.2, 0]
    ant2_loc = [0.3, -0.4]

    ###########################
    fig, ax = plt.subplots(1,1,sharex=True, gridspec_kw={'hspace': 0}, figsize=(5,2))

    # Overall styling
    if True:
        ax.set_aspect('equal')
        ax.spines['top'].set_visible(False)
        ax.spines['right'].set_visible(False)
        ax.spines['bottom'].set_visible(False)
        ax.spines['left'].set_visible(False)

        #ax.axis('off')
        ax.set_xticks([])
        ax.set_xticklabels([])
        #ax.set_ylim(-0.2, 1.2)
        #ax.set_xlim(0, 1)
        #ax.set_ylim(0, 1)
        ax.set_yticks([])
        ax.set_yticklabels([])

    # Transmitter
    t = ax.plot(*trans_loc, '*', **trans_kwargs)
    ax.annotate('$T$', xy=trans_loc, ha='right', va='bottom')

    # Antenna
    ants = []
    annoti_kwargs = [
            dict(text_kw=dict(va='bottom', ha='left')),
            dict(text_kw=dict(va='top', ha='right'))
            ]
    for i, loc in enumerate([ant1_loc, ant2_loc], start=1):
        ants.append(
            ax.plot(*loc, '*', **ant_kwargs)
        )

        ## Distance between Antenna and Transmitter
        default_annot_kwargs = {
        }
        _annotate_width(ax, f"$d_{i}$", trans_loc, loc, text_dx=(0,0.001), **{**default_annot_kwargs, **annot_kwargs, **annoti_kwargs[i-1]} )

        if True:
            ax.annotate(f"$A_{i}$", xy=loc, ha='left', va=['bottom', 'top'][i-1])

    # Distance between two antennas
    _annotate_width(ax, f"$d_{{12}}$", ant1_loc, ant2_loc, text_dx=(0.01,0), text_kw=dict(ha='left', va='top'))

    return fig, 0


if __name__ == "__main__":
    from argparse import ArgumentParser
    import os.path as path

    parser = ArgumentParser(description=__doc__)
    parser.add_argument("fname", metavar="path/to/figure[/]", nargs="?", help="Location for generated figure, will append __file__ if a directory. If not supplied, figure is shown.")

    args = parser.parse_args()

    if args.fname is not None and path.isdir(args.fname):
        args.fname = path.join(args.fname, path.splitext(path.basename(__file__))[0] + ".pdf")

    ###
    fig, _ = main()

    if args.fname is not None:
        plt.savefig(args.fname)
    else:
        plt.show()