Refactor plotters into classes

visualizer/plotting.py

 """Plotting functions."""
 
-from dataclasses import make_dataclass
 from io import BytesIO
 from types import SimpleNamespace
 
@@ -17,23 +16,19 @@ plt.style.use('ggplot')
 plt.rcParams['axes.xmargin'] = 0
 matplotlib.use('Agg')
 
-Plotter = make_dataclass('Plotter', ['name', 'nav_title', 'plot'])
-plotters = {}
 
+class Plotter:
+    """Parent of plotter classes."""
 
-def add_plotter(name, nav_title):
-    """Decorator to register a plot type."""
 
-    def decorator(f):
-        plotters[name] = Plotter(name, nav_title, f)
-        return f
-
-    return decorator
+class TimeSeries(Plotter):
+    """Plot one station/year/measurement."""
 
+    name = 'time-series'
+    nav_title = 'Time Series'
 
-@add_plotter('time-series', 'Time Series')
-def plot_time_series():
-    """Plot one station/year/measurement."""
+    @classmethod
+    def plot(cls):
         station_id = get_param('station')
         year = get_param('year', to=year_type)
         meas = get_param('measurement', to=meas_type)
@@ -55,21 +50,26 @@ def plot_time_series():
         minimum = min(data, key=lambda row: row[meas.field])
         axes.set_title(
             (f'Max {meas.title}: {maximum[meas.field]}, Date: ({maximum[0]}). '
-         f'Min {meas.title}: {minimum[meas.field]}, Date: ({minimum[0]}).'),
+             f'Min {meas.title}: {minimum[meas.field]}, '
+             f'Date: ({minimum[0]}).'),
             fontsize='small',
         )
         name = station['name']
         plt.suptitle(f'{meas.title} measurements, {name} Station, '
                      f'{data[0][0].year}')
-    return savefig_response(
-        fig,
-        filename=f'time-series.{station_id}.{year}.{meas.url_name}.png',
-    )
+        return savefig_response(fig, filename=(
+            f'{cls.name}.{station_id}.{year}.{meas.url_name}.png'
+        ))
 
 
-@add_plotter('overlay', 'Overlay')
-def plot_overlay():
+class Overlay(Plotter):
     """Plot two station/years @ one measurement."""
+
+    name = 'overlay'
+    nav_title = 'Overlay'
+
+    @classmethod
+    def plot(cls):
         num_datasets = 2
         datasets = tuple(SimpleNamespace() for _ in range(num_datasets))
         stations = read_stations()
@@ -81,7 +81,8 @@ def plot_overlay():
         meas = get_param('measurement', to=meas_type)
 
         def ignore_feb_29(rows):
-        return [row for row in rows if (row[0].month, row[0].day) != (2, 29)]
+            return [row for row in rows
+                    if (row[0].month, row[0].day) != (2, 29)]
 
         for dset in datasets:
             raw_data = read_data(dset.station, dset.year)
@@ -112,7 +113,8 @@ def plot_overlay():
         min_dset = min(datasets, key=lambda dset: dset.min[meas.field])
 
         axes.grid(True)
-    axes.set_title((f'Max {meas.title}: {max_dset.max[meas.field]}, '
+        axes.set_title(
+            (f'Max {meas.title}: {max_dset.max[meas.field]}, '
              f'{max_dset.name} Station, Date: ({max_dset.max[0]}). '
              f'Min {meas.title}: {min_dset.min[meas.field]}, '
              f'{min_dset.name} Station, Date: ({min_dset.min[0]}).'),
@@ -124,15 +126,19 @@ def plot_overlay():
         plt.suptitle(f'{meas.title} measurements, {title_dsets}')
         filename_dsets = '.'.join(f'{dset.station_id}.{dset.year}'
                                   for dset in datasets)
-    return savefig_response(
-        fig,
-        filename=f'overlay.{filename_dsets}.{meas.url_name}.png',
-    )
+        return savefig_response(fig, filename=(
+            f'{cls.name}.{filename_dsets}.{meas.url_name}.png'
+        ))
 
 
-@add_plotter('boxplot', 'Boxplot')
-def plot_boxplot():
+class Boxplot(Plotter):
     """Boxplot one station/measurement @ multiple years."""
+
+    name = 'boxplot'
+    nav_title = 'Boxplot'
+
+    @classmethod
+    def plot(cls):
         station_id = get_param('station')
         year1 = get_param('year1', to=year_type)
         year2 = get_param('year2', to=year_type)
@@ -152,8 +158,7 @@ def plot_boxplot():
 
         for year in years:
             data = read_data(station, year)
-        selected_data = data[:, meas.field]
-        plot_data.append(selected_data)
+            plot_data.append(data[:, meas.field])
 
             year_max = max(data, key=at_index)
             year_min = min(data, key=at_index)
@@ -171,16 +176,19 @@ def plot_boxplot():
         axes.grid(True)
         axes.set_title(
             (f'Max {meas.title}: {maximum[meas.field]}, Date: ({maximum[0]}). '
-         f'Min {meas.title}: {minimum[meas.field]}, Date: ({minimum[0]}).'),
+             f'Min {meas.title}: {minimum[meas.field]}, '
+             f'Date: ({minimum[0]}).'),
             fontsize='small',
         )
         name = station['name']
         plt.suptitle(f'{meas.title} measurements, {name} Station, '
                      f'{start_year} - {end_year}.')
-    return savefig_response(
-        fig,
-        filename=(f'boxplot.{station_id}.{year1}.{year2}.{meas.url_name}.png'),
-    )
+        return savefig_response(fig, filename=(
+            f'{cls.name}.{station_id}.{year1}.{year2}.{meas.url_name}.png'
+        ))
+
+
+plotters = {plotter.name: plotter for plotter in Plotter.__subclasses__()}
 
 
 def savefig_response(fig, filename=None):