refactor: move month_year_picker to common and make it more generic

app/apps/common/urls.py

@@ -8,4 +8,9 @@ urlpatterns = [
         views.toasts,
         name="toasts",
     ),
+    path(
+        "ui/month-year-picker/",
+        views.month_year_picker,
+        name="month_year_picker",
+    ),
 ]

app/apps/common/views.py

@@ -1,5 +1,86 @@
+from dateutil.relativedelta import relativedelta
+from django.db.models import Count
+from django.db.models.functions import ExtractYear, ExtractMonth
 from django.shortcuts import render
+from django.urls import reverse
+from django.utils import timezone
+
+from apps.transactions.models import Transaction
 
 
 def toasts(request):
-    return render(request, "common/toasts.html")
+    return render(request, "common/fragments/toasts.html")
+
+
+def month_year_picker(request):
+    field = request.GET.get("field", "reference_date")
+    for_ = request.GET.get("for", None)
+    url = None
+
+    if for_ == "calendar":
+        url = "calendar"
+    elif for_ == "monthly_overview":
+        url = "monthly_overview"
+
+    # Get current month and year from request or use current date
+    current_date = timezone.localdate(timezone.now())
+    current_month = int(request.GET.get("month", current_date.month))
+    current_year = int(request.GET.get("year", current_date.year))
+
+    # Set start and end dates
+    start_date = timezone.datetime(current_year - 1, 1, 1).date()
+    end_date = timezone.datetime(current_year + 1, 12, 31).date()
+
+    # Get years from transactions
+    transaction_years = Transaction.objects.dates(field, "year", order="ASC")
+
+    # Extend start_date and end_date if necessary
+    if transaction_years:
+        start_date = min(start_date, transaction_years.first().replace(month=1, day=1))
+        end_date = max(end_date, transaction_years.last().replace(month=12, day=31))
+
+    # Generate all months between start_date and end_date
+    all_months = []
+    current_month_date = start_date
+    while current_month_date <= end_date:
+        all_months.append(current_month_date)
+        current_month_date += relativedelta(months=1)
+
+    # Get transaction counts for each month
+    transaction_counts = (
+        Transaction.objects.annotate(year=ExtractYear(field), month=ExtractMonth(field))
+        .values("year", "month")
+        .annotate(transaction_count=Count("id"))
+        .order_by("year", "month")
+    )
+
+    # Create a dictionary for quick lookup
+    count_dict = {
+        (item["year"], item["month"]): item["transaction_count"]
+        for item in transaction_counts
+    }
+
+    # Create the final result
+    result = [
+        {
+            "year": date.year,
+            "month": date.month,
+            "transaction_count": count_dict.get((date.year, date.month), 0),
+            "url": (
+                reverse(url, kwargs={"month": date.month, "year": date.year})
+                if url
+                else ""
+            ),
+        }
+        for date in all_months
+    ]
+
+    return render(
+        request,
+        "common/fragments/month_year_picker.html",
+        {
+            "month_year_data": result,
+            "current_month": current_month,
+            "current_year": current_year,
+        },
+    )