Initial commit — Moon Household Budget

debts.py

@@ -0,0 +1,194 @@
+import json
+import os
+from datetime import date
+import math
+
+DATA_DIR = os.path.join(os.path.dirname(__file__), "data")
+DEBTS_FILE = os.path.join(DATA_DIR, "debts.json")
+DEBT_LOG_FILE = os.path.join(DATA_DIR, "debt_log.json")
+
+DEBT_CATEGORIES = ["Credit Cards", "BNPL", "Medical Payment Plans"]
+
+BNPL_FREQUENCIES = {
+    "biweekly": 14,
+    "monthly": 30,
+    "4-payment": 14,
+}
+
+
+def simulate_payoff(debts, extra_monthly, method="avalanche"):
+    import copy
+    from datetime import date
+    from dateutil.relativedelta import relativedelta
+
+    # Only credit cards and medical debts with a balance
+    active = [d for d in debts if not d.get("is_bnpl") and d.get("active", True)
+              and float(d.get("current_balance", 0)) > 0]
+    if not active:
+        return [], 0, 0, 0
+
+    # Build working copies
+    working = []
+    for d in active:
+        working.append({
+            "id": d["id"],
+            "name": d["name"],
+            "owner": d.get("owner", ""),
+            "balance": float(d.get("current_balance", 0)),
+            "apr": float(d.get("apr", 0)),
+            "minimum": float(d.get("minimum", 0)),
+            "paid_off_month": None,
+            "total_interest": 0,
+            "total_paid": 0,
+        })
+
+    total_minimum = sum(w["minimum"] for w in working)
+    extra = max(extra_monthly - total_minimum, 0)
+
+    current_month = date.today().replace(day=1)
+    total_interest = 0
+    months = 0
+    max_months = 600
+
+    while any(w["balance"] > 0 for w in working) and months < max_months:
+        months += 1
+        current_month_label = current_month.strftime("%b %Y")
+
+        # Sort target debt
+        unpaid = [w for w in working if w["balance"] > 0]
+        if method == "avalanche":
+            unpaid.sort(key=lambda x: -x["apr"])
+        else:
+            unpaid.sort(key=lambda x: x["balance"])
+
+        # Apply interest and minimums
+        for w in unpaid:
+            if w["balance"] <= 0:
+                continue
+            monthly_rate = (w["apr"] / 100) / 12
+            interest = round(w["balance"] * monthly_rate, 2)
+            w["balance"] = round(w["balance"] + interest, 2)
+            w["total_interest"] += interest
+            total_interest += interest
+            payment = min(w["minimum"], w["balance"])
+            w["balance"] = round(w["balance"] - payment, 2)
+            w["total_paid"] += payment
+
+        # Apply extra to target
+        remaining_extra = extra
+        for w in unpaid:
+            if w["balance"] <= 0:
+                continue
+            extra_payment = min(remaining_extra, w["balance"])
+            w["balance"] = round(w["balance"] - extra_payment, 2)
+            w["total_paid"] += extra_payment
+            remaining_extra -= extra_payment
+            if remaining_extra <= 0:
+                break
+
+        # Roll over freed minimums as extra for next debt
+        for w in working:
+            if w["balance"] <= 0 and w["paid_off_month"] is None:
+                w["paid_off_month"] = current_month_label
+                extra += w["minimum"]
+
+        from datetime import timedelta
+        current_month = (current_month.replace(day=28) + timedelta(days=4)).replace(day=1)
+
+    return working, round(total_interest, 2), months, round(total_minimum + extra_monthly, 2)
+
+
+def bnpl_payoff_date(payments_made, total_payments, frequency_days):
+    from datetime import date, timedelta
+    today = date.today()
+    remaining = total_payments - payments_made
+    if remaining <= 0:
+        return None, 0
+    days = remaining * frequency_days
+    payoff = today + timedelta(days=days)
+    return payoff.strftime("%b %Y"), remaining
+
+OWNER_COLORS = {
+    "Bonna": "#D4B8C5",
+    "Tony":  "#A0B8C5",
+    "Both":  "#B8A8D4",
+}
+
+
+def load_debts():
+    if os.path.exists(DEBTS_FILE):
+        with open(DEBTS_FILE) as f:
+            return json.load(f)
+    return []
+
+
+def save_debts(debts):
+    with open(DEBTS_FILE, "w") as f:
+        json.dump(debts, f, indent=2)
+
+
+def load_debt_log():
+    if os.path.exists(DEBT_LOG_FILE):
+        with open(DEBT_LOG_FILE) as f:
+            return json.load(f)
+    return {}
+
+
+def save_debt_log(log):
+    with open(DEBT_LOG_FILE, "w") as f:
+        json.dump(log, f, indent=2)
+
+
+def month_key(year, month):
+    return f"{year}-{month:02d}"
+
+
+def monthly_interest(balance, apr):
+    if not apr or apr <= 0:
+        return 0
+    return round(balance * (apr / 100) / 12, 2)
+
+
+def payoff_months(balance, apr, monthly_payment, monthly_charges=0):
+    if monthly_payment <= 0:
+        return None
+    if apr and apr > 0:
+        monthly_rate = (apr / 100) / 12
+    else:
+        monthly_rate = 0
+
+    b = balance
+    months = 0
+    while b > 0 and months < 600:
+        b = b + (b * monthly_rate) + monthly_charges - monthly_payment
+        months += 1
+        if monthly_charges == 0 and b >= balance:
+            return None
+    return months if months < 600 else None
+
+
+def get_debt_month(debt_id, year, month):
+    log = load_debt_log()
+    mk = month_key(year, month)
+    return log.get(mk, {}).get(debt_id, {})
+
+
+def update_debt_month(debt_id, year, month, data):
+    log = load_debt_log()
+    mk = month_key(year, month)
+    log.setdefault(mk, {})[debt_id] = data
+    save_debt_log(log)
+
+
+def compute_ending_balance(debt, year, month):
+    mk = month_key(year, month)
+    log = load_debt_log()
+    entry = log.get(mk, {}).get(debt["id"], {})
+
+    starting = entry.get("starting_balance", debt.get("current_balance", 0))
+    interest = entry.get("interest") if entry.get("interest") is not None else monthly_interest(starting, debt.get("apr", 0))
+    new_charges = entry.get("new_charges", 0)
+    payment = entry.get("payment", 0)
+
+    ending = round(float(starting) + float(interest) + float(new_charges) - float(payment), 2)
+    return max(ending, 0)