import matplotlib.pyplot as plt

def raymers_iterate(current_max_weight, payload_weight, fuel_weight, a_constant, c_constant, variable_sweep_constant):
    empty_max_weight_ratio =  (a_constant * current_max_weight**c_constant * variable_sweep_constant)

    new_max_weight = payload_weight / (1 - (fuel_weight / current_max_weight) - (empty_max_weight_ratio))
    return new_max_weight

payload_mass_metric = 125 # Grams
payload_mass_imperial = payload_mass_metric * 0.002204623 # Converting grams to pounds

a_constant = 0.86 # Sailplane - Unpowered
c_constant = -0.05 # Sailplane - Unpowered

max_weight_guess = 6 # Initial weight guess of 6 lbs
current_estimate = max_weight_guess

imperial_estimates = []

for i in range(0,11):
    current_estimate = raymers_iterate(current_estimate, payload_mass_imperial, 0, a_constant, c_constant, 1)
    imperial_estimates.append(current_estimate)

metric_estimates = []

for imperial_estimate in imperial_estimates:
    metric_estimates.append(imperial_estimate / 0.002204623)

plt.plot(metric_estimates, linestyle='--', marker='o')

# Add labels to each point
for index, weight in enumerate(metric_estimates):
    plt.text(index, weight + 5, f'{index}: {weight:.2f}', fontsize=9, ha='right')

plt.title("Aircraft Raymer's Method Weight Estimation")
plt.xlabel("Iteration Number")
plt.ylabel("Weight Estimation (g)")
plt.grid(True)
plt.show()