269 lines
13 KiB
Python
269 lines
13 KiB
Python
# calc.py
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from datetime import datetime, timedelta
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# GLOBAL CONSTANTS
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LEASE = 0
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def add_annotation(finance, dt, total, delta, text):
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# dont add an annotation for small changes (jic)
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tm = dt.timestamp() * 1000
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if delta > 0:
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text += f": ${int(abs(delta))}"
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else:
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text += f": -${int(abs(delta))}"
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finance['annotations'].append( { 'label': text, 'x': tm, 'y': total } )
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return
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def calculate_savings_depletion(finance):
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# Extract all the financial data from the database
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D_Salary = finance['D_Salary']
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D_Num_fortnights_pay = finance['D_Num_fortnights_pay']
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School_Fees = finance['School_Fees']
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Car_loan_via_pay = finance['Car_loan_via_pay']
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Car_loan = finance['Car_loan']
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Car_balloon = finance['Car_balloon']
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Car_buyout = finance['Car_buyout']
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Living_Expenses = finance['Living_Expenses']
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Savings = finance['Savings']
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Interest_Rate = finance['Interest_Rate']
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Inflation = finance['Inflation']
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Mich_present = finance['Mich_present']
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Overseas_trip = finance['Overseas_trip']
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Mark_reno = finance['Mark_reno']
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D_leave_owed_in_days = finance['D_leave_owed_in_days']
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Sell_shares = finance['Sell_shares']
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D_TLS_shares = finance['D_TLS_shares']
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M_TLS_shares = finance['M_TLS_shares']
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D_CBA_shares = finance['D_CBA_shares']
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TLS_price = finance['TLS_price']
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CBA_price = finance['CBA_price']
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Ioniq6_future = finance['Ioniq6_future']
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### COMPLEX tax implications with my leave I have not taken. It will be taxed in the year I 'quit' ###
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# leave in days, 10 business days to a fortnight,
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# paid before tax I earn $7830.42 / fortnight. Tax on that will be at 37% or $4933.16 after tax
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# if we could stretch this to July 2026, then would be more (due to less tax)
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bus_days_in_fortnight=10
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# this is what I earn before-tax
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pre_tax_D_earning = 7830.42
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# as the leave is just on top of my existing earnings and if in 2024 fin year, just take tax at 37% for the extra leave amount
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D_leave_after_tax = (D_leave_owed_in_days/bus_days_in_fortnight) * pre_tax_D_earning * (1-0.37)
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# However, if I quit in the next fin year - tax for 2025 will be: $4,288 plus 30c for each $1 over $45,000
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# (assuming the 7830.42 * ~90/bus_days_in_fortnight = ~ $64k - > 45k and < $135k bracket is 30%)
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# Given, I probably can't stop Deakin doing PAYG deductions, I won't get
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# the tax back until the end of the financial year, so work out the
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# amount of tax I will get back info: tax_diff_D_leave
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tax_on_leave = (pre_tax_D_earning * (D_leave_owed_in_days/bus_days_in_fortnight) - 45000)*.3 + 4288
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D_leave_after_tax_new_fin_year = pre_tax_D_earning * (D_leave_owed_in_days/bus_days_in_fortnight) - tax_on_leave
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tax_diff_D_leave = D_leave_after_tax_new_fin_year-D_leave_after_tax
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### leave / tax items finished ###
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# convenience vars to make it easier to read conditional leave tax/payment logic below
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D_has_quit = False
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D_quit_year = 0
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claim_tax_on_leave = False
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new_fin_year_25 = datetime(2025, 7, 1)
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new_fin_year_26 = datetime(2026, 7, 1)
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# Constants for interest calculations
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annual_interest_rate = Interest_Rate / 100.0
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daily_interest_rate = annual_interest_rate / 365
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# main loop range -- start from now, and simulate till D is 60 (April 2031)
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current_date = datetime.now()
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end_date = datetime(2031, 4, 15)
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# Calculate daily living expenses
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daily_living_expenses = Living_Expenses / 365
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# take a stab at future rego and insurance on the Ioniq 6 when we finish the lease - paid every anniversary of the Car balloon payment date
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ioniq6_rego = 800
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ioniq6_ins = 2200
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# Start the calculation
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current_savings = Savings
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depletion_date = None
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savings_per_fortnight = []
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# significant dates that are non-changeable
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school_fees_date = datetime(2025, 12, 5)
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car_balloon_date = datetime(2026, 11, 15)
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mich_present_date = datetime(2026,10,15)
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# significant dates - but who knows when? :)
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overseas_trip_date = datetime.strptime( finance['Overseas_trip_date'], "%Y-%m-%d")
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mark_reno_date = datetime.strptime( finance['Mark_reno_date'], "%Y-%m-%d")
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car_buyout_date = datetime.strptime( finance['Car_buyout_date'], "%Y-%m-%d")
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# to force deakin pay cycles to match reality, we work from the 8th of Jan as our "day-zero" so we are paid on the 8/1/25, 22/1/25, etc.
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days_count = ( current_date - datetime(2025,1,1) ).days
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# Track the fortnight, and monthly interest
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fortnight_income = 0
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monthly_interest = 0
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# Create an empty dict to store annotations to display in the GUI
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# (key is date, text is for larger spend items by hand)
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finance['annotations']=[]
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while current_date <= end_date:
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#paid on 8th or 22nd of Jan (so 8th day of fortnight)
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is_fortnight = (days_count % 14 == 7)
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is_end_of_month = (current_date.day == 1)
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# Subtract daily living expenses
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current_savings -= daily_living_expenses
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# Calculate daily interest but apply at the end of the month
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monthly_interest += current_savings * daily_interest_rate
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# Apply fortnightly salary and handle car loan deduction
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if is_fortnight:
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if D_Num_fortnights_pay > 0:
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fortnight_income += D_Salary
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D_Num_fortnights_pay -= 1
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# keep paying car off fortnightly until the end of the car loan (while I am still working) - once I quit, pay reverts to monthly on the 15th
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if not D_has_quit and current_date < car_balloon_date:
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current_savings -= Car_loan_via_pay
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print( f"{current_date}: making car loan pay as pre-tax lease: ${Car_loan_via_pay}" )
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if D_Num_fortnights_pay == 0 and D_leave_after_tax > 0:
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D_has_quit = True
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D_quit_year = current_date.year
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# okay, if we leave before Jun 30th 2024, then I pay full tax, otherwise I get 'extra', but have to await end of next fin year
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if current_date > new_fin_year_25:
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claim_tax_on_leave = True
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else:
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claim_tax_on_leave = False
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print(f"{current_date}: D has resigned - get paid out my 9 weeks leave and lose 45% to tax - ${D_leave_after_tax}" )
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current_savings += D_leave_after_tax
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add_annotation(finance, current_date, current_savings, D_leave_after_tax, "D quit" )
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D_leave_after_tax = 0
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# its end of 'next' fin year, if tax_diff > 0, then ddp quit after new tax year and gets back the overpaid tax
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if current_date > new_fin_year_26 and claim_tax_on_leave:
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current_savings += tax_diff_D_leave
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add_annotation(finance, current_date, current_savings, tax_diff_D_leave, "D quit - tax back" )
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# can only claim the tax back once :)
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claim_tax_on_leave=False
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if fortnight_income:
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print(f"{current_date}: salary paid by Deakin - adding: {fortnight_income}" )
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current_savings += fortnight_income
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fortnight_income = 0 # reset for next fortnight
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savings_per_fortnight.append((current_date.strftime("%Y-%m-%d"), round(current_savings, 2)))
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# if I have quit, then car lease payments are made on the 15th of the month for full Car_loan
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if D_has_quit and current_date.day == 15:
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if Ioniq6_future == LEASE and current_date <= car_balloon_date:
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current_savings -= Car_loan
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print( f"{current_date}: making car loan pay (after quitting): ${Car_loan}" )
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elif Ioniq6_future != LEASE and current_date <= car_buyout_date:
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current_savings -= Car_loan
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print( f"{current_date}: making car loan pay (after quitting): ${Car_loan}" )
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if is_end_of_month:
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current_savings += monthly_interest
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#print(f"{current_date}: interest paid - ${monthly_interest}")
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monthly_interest = 0
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# monthly increase living expenses by a monthly inflation multiplier
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Living_Expenses += (Inflation/100.0)/12 * Living_Expenses
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daily_living_expenses = Living_Expenses / 365
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#print(f"{current_date}: Living Exp inceased - ${Living_Expenses}")
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if current_date.date() == school_fees_date.date():
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current_savings -= School_Fees
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add_annotation(finance, current_date, current_savings, -School_Fees, "School Fees")
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if Ioniq6_future == LEASE and current_date.date() == car_balloon_date.date():
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current_savings -= Car_balloon
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add_annotation(finance, current_date, current_savings, -Car_balloon, "car balloon")
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print(f"{current_date}: car balloon - ${Car_balloon}" )
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if Ioniq6_future != LEASE and current_date.date() == car_buyout_date.date():
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current_savings -= Car_buyout
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add_annotation(finance, current_date, current_savings, -Car_buyout, "car buyout")
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print(f"{current_date}: car buyout - ${Car_buyout}" )
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# Anniversary of Car purchase/balloon so potentially insurance/rego
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# when I quit, the if we haven't paid the car outright, then need to add rego, but not insurance
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# if we pay-out the car, then add insurace and rego
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if current_date.month == car_balloon_date.month and current_date.day == car_balloon_date.day:
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# staying with the lease (0), if I have quit, then pay monthly rego only up to lease date, but full cost after car balloon date
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if Ioniq6_future == LEASE:
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if current_date.year >= car_balloon_date.year:
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current_savings -= (ioniq6_ins + ioniq6_rego)
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add_annotation(finance, current_date, current_savings, -(ioniq6_ins+ioniq6_rego), "IONIQ 6 ins/rego" )
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# if we buy car outright, then as long as this anniversary is after buyout date, pay ins and rego
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elif current_date.year >= car_buyout_date.year:
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current_savings -= (ioniq6_ins + ioniq6_rego)
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add_annotation(finance, current_date, current_savings, -(ioniq6_ins+ioniq6_rego), "IONIQ 6 ins/rego" )
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if current_date.date() == overseas_trip_date.date():
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current_savings -= Overseas_trip
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add_annotation(finance, current_date, current_savings, -Overseas_trip, "O/S trip")
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if current_date.date() == mich_present_date.date():
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current_savings -= Mich_present
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add_annotation(finance, current_date, current_savings, -Mich_present, "Mich's present" )
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if current_date.date() == mark_reno_date.date():
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current_savings -= Mark_reno
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add_annotation(finance, current_date, current_savings, -Mark_reno, "Mark/reno" )
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if current_savings < 0:
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depletion_date = current_date
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break
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# twice a year, CBA has a dividend of $2-2.5 DRP gives back around 20ish shares twice a year, estimate this...
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# and on average they exceed interest rate, but lets assume at least int.rate increase (remember its twice a year, so /2)
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if current_date.day == 1 and (current_date.month == 4 or current_date.month == 10):
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CBA_price = CBA_price+ CBA_price * (Interest_Rate/2)/100
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drp = int( (2.25*D_CBA_shares/CBA_price) )
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print( f"DRP {current_date} - adding {drp} CBA shares" )
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D_CBA_shares += int( (2.25*D_CBA_shares/CBA_price) )
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# if selling shares, and its 1st of July...
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# BUT not if D quits before end of financial year - as I won't be able to sell CBA shares for no cap gains
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# so wait until the following year
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if current_date.month == 7 and current_date.day == 1 and D_has_quit and Sell_shares>0 and (current_date.year > D_quit_year or current_date.year == D_quit_year and claim_tax_on_leave == False):
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# 2024 Govt. value
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tax_threshold = 18200
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# cap-gains is 50% of profit (lazy profit calc here, just assume its all profit)
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can_sell = 2*tax_threshold
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actual_sell = 0
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# sell off TLS first - and they are way under the limit, so just sell them all in one hit
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if D_TLS_shares > 0:
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actual_sell += TLS_price*D_TLS_shares
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D_TLS_shares = 0
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if M_TLS_shares > 0:
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actual_sell += TLS_price*M_TLS_shares
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M_TLS_shares = 0
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while actual_sell + CBA_price < can_sell and D_CBA_shares > 0:
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actual_sell += CBA_price
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D_CBA_shares -= 1
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Sell_shares -= 1
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current_savings += actual_sell
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add_annotation(finance, current_date, current_savings, actual_sell, "Sell shares" )
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current_date += timedelta(days=1)
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days_count += 1
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finance['CBA']=D_CBA_shares
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finance['TLS']=D_TLS_shares+M_TLS_shares
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return depletion_date, savings_per_fortnight, current_savings
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