import json

from django.forms import widgets

class PrettyJSONWidget(widgets.Textarea):

    def format_value(self, value):
        try:
            value = json.dumps(json.loads(value), indent=2, sort_keys=True)
            # these lines will try to adjust size of TextArea to fit to content
            row_lengths = [len(r) for r in value.split('\n')]
            self.attrs['rows'] = min(max(len(row_lengths) + 2, 10), 30)
            self.attrs['cols'] = min(max(max(row_lengths) + 2, 40), 120)
            return value
        except Exception as error:
            print("Error while formatting JSON: {}".format(error))
            return super(PrettyJSONWidget, self).format_value(value)
