import inspect
import json
import os
import socket

import matplotlib.pyplot as plt

class PersistentFigure(object):
    def __init__(self, *args, **kwargs):
        self.data_file = os.getcwd() + '/mplpersist.json'
        self.hostname = socket.gethostname()
        frames = inspect.getouterframes(inspect.currentframe())
        self.parent_file = frames[1].filename
        self.parent_function = frames[1].function

        if not os.path.exists(self.data_file):
            with open(self.data_file, 'w') as f:
                json.dump({}, f)

        # set up figure window
        self.figure = plt.figure(*args, **kwargs)
        self.mngr = plt.get_current_fig_manager()
        self.figure_title = self.mngr.get_window_title()

        # manage geometry
        self.key = '%s-%s-%s-%s' % (self.hostname, self.parent_file, self.parent_function, self.figure_title)
        geom = self._load_geometry()
        if geom:
            self.mngr.window.setGeometry(*geom)

        # connect callback
        cid = self.figure.canvas.mpl_connect('resize_event', self._on_resize)

    def _save_geometry(self):
        geom = self.mngr.window.geometry()
        g = geom.getRect()

        with open(self.data_file, 'r') as f:
            data = json.load(f)

        data[self.key] = g

        with open(self.data_file, 'w') as f:
            json.dump(data, f)

    def _load_geometry(self):
        if not os.path.exists(self.data_file):
            print('mpltools.fig.load_geometry_flat: file not found')
            return None

        with open(self.data_file, 'r') as f:
            data = json.load(f)

        return data.get(self.key, None)

    def _on_resize(self, ev):
        self._save_geometry()