add balance prediction page and make it the default

core/prediction.py

@@ -113,3 +113,66 @@ def predict_all(subjects: Iterable[Subject], past_days=30, future_days=60):
         prediction_list.append((subject, transactions, prediction_info))
 
     return prediction_list
+
+
+min_pos_color = (Decimal("50"), Decimal("150"), Decimal("220"))
+max_pos_color = (Decimal("50"), Decimal("170"), Decimal("20"))
+min_neg_color = (Decimal("220"), Decimal("70"), Decimal("30"))
+max_neg_color = (Decimal("180"), Decimal("160"), Decimal("30"))
+
+global_minimum = Decimal("-300")
+global_maximum = Decimal("300")
+
+
+def limit(amount: Decimal, first_bound: Decimal, second_bound: Decimal):
+    lower = min(first_bound, second_bound)
+    upper = max(first_bound, second_bound)
+    return max(min(amount, upper), lower)
+
+
+def get_color_for_amount(amount: Decimal, minimum: Decimal, maximum: Decimal):
+    if amount >= Decimal():
+        minimum = Decimal()
+        maximum = min(maximum, global_maximum)
+        rmin, gmin, bmin = min_pos_color
+        rmax, gmax, bmax = max_pos_color
+    else:
+        minimum = max(minimum, global_minimum)
+        maximum = Decimal()
+        rmin, gmin, bmin = min_neg_color
+        rmax, gmax, bmax = max_neg_color
+    assert minimum < maximum
+    percentage = (amount - minimum) / (maximum - minimum)
+    return "#%02x%02x%02x" % (
+        round(limit(rmin + (percentage * (rmax - rmin)), rmin, rmax)),
+        round(limit(gmin + (percentage * (gmax - gmin)), gmin, gmax)),
+        round(limit(bmin + (percentage * (bmax - bmin)), bmin, bmax)),
+    )
+
+
+def predict_balance(start_balance=Decimal("0")):
+    prediction_list = predict_all(Subject.objects.order_by("name"))
+    today = timezone.now().date()
+    future_transactions = []
+    minimum, maximum = Decimal(), Decimal()
+    for _, transactions, _ in prediction_list:
+        for transaction in transactions:
+            if transaction.booking_date > today:
+                future_transactions.append(transaction)
+                minimum = min(minimum, transaction.amount)
+                maximum = max(maximum, transaction.amount)
+
+    formatted_transactions = []
+    current_balance = start_balance
+    for transaction in sorted(future_transactions, key=lambda t: t.booking_date):
+        current_balance += transaction.amount
+        formatted_transactions.append({
+            "date": transaction.booking_date,
+            "subject": transaction.subject,
+            "amount": transaction.amount,
+            "balance": current_balance,
+            "predicted": transaction.pk is None,
+            "color": get_color_for_amount(transaction.amount, minimum, maximum),
+        })
+
+    return formatted_transactions

core/static/core/style.css

@@ -28,19 +28,17 @@ body {
     color: #EEEEEE;
 }
 
-h1, p, a {
-    margin: 0;
-    border: none;
-    padding: 0;
-    text-decoration: none;
-}
-
 h1 {
-    margin-bottom: 12px;
+    margin: 0 0 12px;
+    padding: 0;
     font-size: 1.3rem;
     font-weight: bold;
 }
 
+p {
+    margin: 6px 0 10px;
+}
+
 #title, #navi, #content {
     flex: 0 1 0;
     width: 95%;
@@ -51,7 +49,7 @@ h1 {
 #title {
     font-size: 1.6rem;
     text-align: center;
-    color: #6699EE;
+    color: #77AAEE;
 }
 
 #navi {
@@ -62,7 +60,8 @@ h1 {
 }
 
 a {
-    color: #6699EE;
+    text-decoration: none;
+    color: #77AAEE;
     transition: color 100ms;
 }
 
@@ -70,19 +69,20 @@ a:hover, a:focus {
     color: #EEEEEE;
 }
 
+form {
+    margin: 12px 0;
+}
+
 form label {
     display: none;
 }
 
-#login-form {
-    display: flex;
-    flex-direction: column;
-    align-items: center;
+form input {
+    margin: 0 0 6px;
 }
 
-#id_username, #id_password, #login-warning, #login-button {
-    flex: 0 1 0;
-    margin: 4px;
+form p {
+    color: #EE9966;
 }
 
 table, thead, tbody, tfoot, tr, td {
@@ -103,7 +103,7 @@ thead {
 }
 
 tr {
-    border-bottom: 1px solid #444;
+    border-bottom: 1px solid #444444;
 }
 
 td {
@@ -151,3 +151,81 @@ td {
         max-width: 240px;
     }
 }
+
+#transaction-list {
+    margin: 12px 0;
+    border: none;
+    padding: 0;
+    display: flex;
+    flex-direction: column;
+}
+
+.transaction-block {
+    flex: 0 1 0;
+    max-width: 800px;
+    margin: 0 0 8px;
+    border-radius: 4px;
+    padding: 4px;
+    display: flex;
+    flex-direction: row;
+}
+
+.transaction-block-first {
+    flex: 1 0 0;
+    margin: 0 8px 0 0;
+}
+
+.transaction-block-second {
+    flex: 0 1 0;
+    margin: 0 0 0 8px;
+    align-items: end;
+}
+
+.transaction-block-first, .transaction-block-second {
+    border: none;
+    padding: 0;
+    display: flex;
+    flex-direction: column;
+    justify-content: space-between;
+}
+
+.date-block, .subject-block, .amount-block, .balance-block {
+    flex: 0 1 0;
+    padding: 3px;
+}
+
+.date-block, .amount-block, .balance-block {
+    white-space: nowrap;
+}
+
+.amount-block, .balance-block {
+    text-align: right;
+}
+
+.amount-block {
+    color: #BBBBBB;
+    background-color: #222222;
+    border-radius: 4px;
+    padding: 3px 6px;
+}
+
+.balance-block {
+    color: #000000;
+    font-size: 1.25rem;
+    font-weight: bold;
+}
+
+@media only screen and (min-width: 480px) {
+    .transaction-block-first, .transaction-block-second {
+        flex-direction: row;
+        align-items: center;
+    }
+
+    .subject-block {
+        flex: 1 0 0;
+    }
+
+    .subject-block, .amount-block {
+        margin: 0 12px;
+    }
+}

core/templates/core/balance.html

@@ -0,0 +1,57 @@
+{% extends "core/base.html" %}
+
+{% block navi %}
+    <a href="{% url 'core:subjects' %}">subjects</a>
+    |
+    <a href="{% url 'admin:index' %}">admin</a>
+    |
+    <a href="{% url 'logout' %}">logout</a>
+{% endblock %}
+
+{% block content %}
+
+    <h1>balance prediction</h1>
+
+    <form method="get" action="{% url 'core:balance' %}">
+        <label for="amount"></label>
+        <input id="amount" name="amount" type="number" step="0.01" placeholder="amount">
+        <input type="submit" value="predict"/>
+        {% if amount_error %}
+            <p>try a number, stupid</p>
+        {% endif %}
+    </form>
+
+    <p>starting with <b>{{ amount }}€</b> ...</p>
+
+    {% if future_transactions %}
+        <div id="transaction-list">
+            {% for transaction in future_transactions %}
+                <div class="transaction-block" style="
+                        background: linear-gradient(90deg, transparent 10%, {{ transaction.color }} 100%);
+                        border-left: 2px solid {{ transaction.color }};
+                        ">
+                    <div class="transaction-block-first">
+                        <div class="date-block" {% if transaction.predicted %}style="color: #77AAEE;"{% endif %}>
+                            {% if transaction.predicted %}&#x1F52E;{% else %}&#x1F5D2;{% endif %}
+                            {{ transaction.date|date:"d.m.Y" }}
+                        </div>
+                        <div class="subject-block">
+                            {{ transaction.subject }}
+                        </div>
+                    </div>
+                    <div class="transaction-block-second">
+                        <div class="amount-block">
+                            {{ transaction.amount }}
+                        </div>
+                        <div class="balance-block">
+                            {{ transaction.balance }}
+                        </div>
+                    </div>
+                </div>
+            {% endfor %}
+        </div>
+    {% else %}
+        <p>no data to show :/</p>
+    {% endif %}
+
+{% endblock %}

core/templates/core/subjects.html

@@ -1,6 +1,8 @@
 {% extends "core/base.html" %}
 
 {% block navi %}
+    <a href="{% url 'core:balance' %}">balance</a>
+    |
     <a href="{% url 'admin:index' %}">admin</a>
     |
     <a href="{% url 'logout' %}">logout</a>
@@ -26,7 +28,7 @@
                         {% if forloop.counter == 1 %}
                             <td rowspan="{{ transactions|length }}" class="subject-cell">{{ subject.name }}</td>
                         {% endif %}
-                        <td class="date-cell">
+                        <td class="date-cell" {% if not transaction.pk %}style="color: #77AAEE;"{% endif %}>
                             {% if transaction.pk %}&#x1F5D2;{% else %}&#x1F52E;{% endif %}
                             {{ transaction.booking_date|date:"d.m.y" }}
                         </td>
@@ -37,9 +39,7 @@
             </tbody>
         </table>
     {% else %}
-        <p>
-            no data to show :/
-        </p>
+        <p>no data to show :/</p>
     {% endif %}
 
 {% endblock %}

core/templates/registration/login.html

@@ -6,19 +6,17 @@
 
 {% block content %}
 
-    <form id="login-form" method="post" action="{% url 'login' %}">
+    <form method="post" action="{% url 'login' %}">
         {% csrf_token %}
-        <label for="id_username">username</label>
-        <input id="id_username" name="username" type="text" placeholder="username">
-        <label for="id_password">password</label>
-        <input id="id_password" name="password" type="password" placeholder="password">
-        {% if form.errors %}
-            <div id="login-warning">
-                nope.
-            </div>
-        {% endif %}
-        <input id="login-button" type="submit" value="login"/>
+        <label for="username"></label>
+        <input id="username" name="username" type="text" placeholder="username">
+        <label for="password">password</label>
+        <input id="password" name="password" type="password" placeholder="password">
+        <input type="submit" value="login"/>
         <input type="hidden" name="next" value="{{ next }}"/>
+        {% if form.errors %}
+            <p>nope.</p>
+        {% endif %}
     </form>
 
 {% endblock %}

core/urls.py

@@ -2,9 +2,10 @@ from django.contrib.auth.decorators import login_required
 from django.urls import path
 from django.views.generic import RedirectView
 
-from core.views import SubjectsView
+from core.views import BalanceView, SubjectsView
 
 urlpatterns = [
-    path("", RedirectView.as_view(pattern_name="core:subjects", permanent=False), name="index"),
+    path("", RedirectView.as_view(pattern_name="core:balance", permanent=False), name="index"),
+    path("balance/", login_required(BalanceView.as_view()), name="balance"),
     path("subjects/", login_required(SubjectsView.as_view()), name="subjects"),
 ]

core/views.py

@@ -1,7 +1,26 @@
+from decimal import Decimal, InvalidOperation
+
 from django.views.generic import TemplateView
 
 from core.models import Subject
-from core.prediction import predict_all
+from core.prediction import predict_all, predict_balance
+
+
+class BalanceView(TemplateView):
+    template_name = "core/balance.html"
+
+    def get_context_data(self, **kwargs):
+        context = super().get_context_data(**kwargs)
+        amount, amount_error = Decimal(), False
+        if amount_query := self.request.GET.get("amount"):
+            try:
+                amount = Decimal(amount_query)
+            except InvalidOperation:
+                amount_error = True
+        context["amount"] = round(amount, 2)
+        context["amount_error"] = amount_error
+        context["future_transactions"] = predict_balance(amount)
+        return context
 
 
 class SubjectsView(TemplateView):