mybuddy/reports/graphs/diaperchange_lifetimes.py

# -*- coding: utf-8 -*-
from django.utils.translation import gettext as _

import plotly.offline as plotly
import plotly.graph_objs as go

from reports import utils


def diaperchange_lifetimes(changes):
    """
    Create a graph showing how long diapers last (time between changes).
    :param changes: a QuerySet of Diaper Change instances.
    :returns: a tuple of the the graph's html and javascript.
    """
    changes = changes.order_by('time')
    durations = []
    last_change = changes.first()
    for change in changes[1:]:
        duration = change.time - last_change.time
        if duration.seconds > 0:
            durations.append(duration)
        last_change = change

    trace = go.Box(
        y=[round(d.seconds/3600, 2) for d in durations],
        name=_('Changes'),
        jitter=0.3,
        pointpos=-1.8,
        boxpoints='all'
    )

    layout_args = utils.default_graph_layout_options()
    layout_args['height'] = 800
    layout_args['title'] = _('<b>Diaper Lifetimes</b>')
    layout_args['yaxis']['title'] = _('Time between changes (hours)')
    layout_args['yaxis']['zeroline'] = False
    layout_args['yaxis']['dtick'] = 1

    fig = go.Figure({
        'data': [trace],
        'layout': go.Layout(**layout_args)
    })
    output = plotly.plot(fig, output_type='div', include_plotlyjs=False)
    return utils.split_graph_output(output)