# -*- coding: utf-8 -*-
""" Controllers for building graphs using pandas library

"""
import base64
import matplotlib
matplotlib.use("Agg")
import matplotlib.pyplot as plt

from gluon.storage import Storage
from graph_tools import (FROM_TO,
                         LABELY_YEAR,
                         linechart,
                         savefig,
                         stackchart)


def dashboard():
    """Return a pre-configure linechart for public used.
    Cumulative distribution for the publications are shown for
    the current year.

    """
    current_year = request.now.year

    selector = Storage()
    selector.Graph_selectorCumulative = "true"
    selector.Graph_selectorId = ""
    selector.Graph_selectorId_authors_roles = ""
    selector.Graph_selectorId_graphs = ""
    selector.Graph_selectorId_projects = ""
    selector.Graphs_selectorId_teams = ""
    selector.Graph_selectorTime = ""
    selector.Graph_selectorYear_start = ""
    selector.Graph_selectorYear_end = ""

    # figure layout
    fig, (ax1, ax2) = plt.subplots(nrows=1, ncols=2, sharey=True)

    # the number of publications per year except for the current year
    min_year = "2009"
    max_year = str(current_year - 1)

    selector.Graph_selectorCumulative = "false"
    selector.Graph_selectorTime = T("year")
    selector.Graph_selectorYear_start = min_year
    selector.Graph_selectorYear_end = max_year

    title = (T(FROM_TO) % (min_year, max_year)).decode("utf-8")
    ylabel = T(LABELY_YEAR).decode("utf-8")

    linechart(db,
              selector,
              target=ax1,
              xlabel="",
              ylabel=ylabel,
              title=title)

    # the cumulative sum of publications for the current year on a month
    year = str(current_year)
    selector.Graph_selectorCumulative = "true"
    selector.Graph_selectorTime = T("month")
    selector.Graph_selectorYear_start = year
    selector.Graph_selectorYear_end = ""

    title = (T("In %s") % year).decode("utf-8")
    linechart(db, selector, target=ax2, title=title)

    # delegate the rendering to the view
    response.view = "graphs/index.html"
    return dict(data=savefig(fig, "svg"))


def publications_versus_time():
    """Generate graph showing the number of publication per month / year
    either as a line chart or as a stacked histograms.

    """
    # user criteria and graph configuration
    selector = request.vars
    graph = db.graphs[selector.Graph_selectorId_graphs]
    axis = graph.stack_axis

    # instantiate the graph
    ax = (stackchart(db, selector) if axis else linechart(db, selector))

    # delegate the rendering to the view
    extension = request.extension
    fmt = "svg" if extension == "html" else extension

    # base64 string encoding
    data = savefig(ax.get_figure(), fmt)
    if fmt in ("pdf", "png"):
        data = base64.b64encode(data)

    response.view = "graphs/index.%s" % extension
    return dict(data=data)