Add first plot

nummi/main/models.py

@@ -194,7 +194,7 @@ class Snapshot(models.Model):
     @property
     def sum(self):
         if self.previous is None:
-            return None
+            return 0
         trans = self.transactions.aggregate(sum=models.Sum("value"))
         return trans["sum"] or 0
 
@@ -206,6 +206,24 @@ class Snapshot(models.Model):
             date__lte=self.date, date__gt=self.previous.date
         )
 
+    @property
+    def pos(self):
+        return (
+            self.transactions.filter(value__gt=0).aggregate(sum=models.Sum("value"))[
+                "sum"
+            ]
+            or 0
+        )
+
+    @property
+    def neg(self):
+        return (
+            self.transactions.filter(value__lt=0).aggregate(sum=models.Sum("value"))[
+                "sum"
+            ]
+            or 0
+        )
+
     class Meta:
         ordering = ["-date"]
         verbose_name = _("Snapshot")

nummi/nummi/urls.py

@@ -20,6 +20,7 @@ from django.views.generic.base import RedirectView
 
 urlpatterns = i18n_patterns(
     path("", include("main.urls")),
+    path("plot/", include("plot.urls")),
     path("admin/", admin.site.urls),
     prefix_default_language=False,
 )

nummi/plot/admin.py

@@ -0,0 +1,3 @@
+from django.contrib import admin
+
+# Register your models here.

nummi/plot/apps.py

@@ -0,0 +1,6 @@
+from django.apps import AppConfig
+
+
+class PlotConfig(AppConfig):
+    default_auto_field = "django.db.models.BigAutoField"
+    name = "plot"

nummi/plot/models.py

@@ -0,0 +1,3 @@
+from django.db import models
+
+# Create your models here.

nummi/plot/nummi.mplstyle

@@ -0,0 +1,13 @@
+font.family: Inter
+
+lines.linewidth: 2
+
+figure.autolayout: True
+figure.figsize: 8, 4
+figure.dpi: 300
+
+axes.prop_cycle: cycler('color', ["66cc66", "#338033", "#99ff99", "#802653", "#cc6699"])
+axes.xmargin: 0
+axes.grid: True
+
+svg.fonttype: none

nummi/plot/tests.py

@@ -0,0 +1,3 @@
+from django.test import TestCase
+
+# Create your tests here.

nummi/plot/urls.py

@@ -0,0 +1,7 @@
+from django.urls import path
+
+from . import views
+
+urlpatterns = [
+    path("timeline", views.timeline, name="timeline"),
+]

nummi/plot/views.py

@@ -0,0 +1,40 @@
+import io
+
+import matplotlib
+import matplotlib.pyplot as plt
+from matplotlib import dates as mdates
+from django.contrib.auth.decorators import login_required
+from django.http import HttpResponse
+from django.utils.translation import gettext as _
+
+from main.models import (
+    Transaction,
+    Invoice,
+    Category,
+    Snapshot,
+)
+
+
+matplotlib.use("Agg")
+plt.style.use("./plot/nummi.mplstyle")
+
+
+@login_required
+def timeline(request):
+    _snapshots = Snapshot.objects.all()
+
+    fig, ax = plt.subplots()
+    ax.step(
+        [s.date for s in _snapshots],
+        [s.value for s in _snapshots],
+        where="post",
+    )
+    ax.set(ylabel=_("Snapshots"), ylim=0)
+    ax.xaxis.set_major_formatter(
+        mdates.ConciseDateFormatter(ax.xaxis.get_major_locator())
+    )
+    _io = io.StringIO()
+
+    fig.savefig(_io, format="svg")
+
+    return HttpResponse(_io.getvalue(), headers={"Content-Type": "image/svg+xml"})