clusterview2/clusterview2/point_manager.py

import json

from clusterview2.colors import Color
from clusterview2.points import PointSet


class PointManager():
    """
    A state class that represents the absolute state of the
    world in regards to points.
    """

    point_set = None
    clusters = []

    @staticmethod
    def load(location):
        """
        Loads the JSON file from the location and populates point_set
        with it's contents.

        @param location The location of the JSON file.
        """
        with open(location) as json_file:
            data = json.load(json_file)

            PointManager.point_set = PointSet(data['point_size'],
                                              data['viewport_width'],
                                              data['viewport_height'])

            for point in data['points']:
                # We will need to cast the string representation of color
                # back into a Color enum.
                PointManager.point_set.add_point(point['x'], point['y'],
                                                 Color(point['color']), point['weight'])

    @staticmethod
    def save(location):
        """
        Persists the point_set as a JSON file at location.

        @param location The persistence location.
        """

        data = {}
        data['point_size'] = PointManager.point_set.point_size
        data['viewport_width'] = PointManager.point_set.viewport_width
        data['viewport_height'] = PointManager.point_set.viewport_height
        data['points'] = []

        for p in PointManager.point_set.points:
            data['points'].append({
                'x': p.x,
                'y': p.y,
                'color': p.color,
                'weight': p.weight
            })

        with open(location, 'w') as out_file:
            json.dump(data, out_file)