import matplotlib.pyplot as plt
import math

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')

# This section has been commented out because jordan (senft) does not believe the customer wants to see the numbers
# 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()

print("Raymer's Aircraft Calculations (IMPERIAL UNITS)\n")
print("Weight Estimation: %0.4f lbs" % imperial_estimates[-1])

# Wing loading 
typical_weight_area_ratio = 6 # Historical sailplane ratio
print("Typical Weight Area Ratio: %0.4f lbs/ft^2" % typical_weight_area_ratio)

# To find area of the wings we must work backwards (ratio = weight/area)
# Area of wings
wing_area = imperial_estimates[-1] / typical_weight_area_ratio
print("Main Wing Area: %0.4f ft^2" % wing_area)

# L/D Ratio
ld_ratio = 7.5 / 1.5
print("Lift to Drag Ratio: %0.4f" % ld_ratio)

# Aspect Ratio (Wing span) - Need L/D
aspect_ratio = 4.464 * (ld_ratio**0.69)
print("Aspect Ratio: %0.4f" % aspect_ratio)

# Wing span
wing_span = math.sqrt(aspect_ratio*wing_area)
print("Main Wing Span %0.4f ft" % wing_span)

# Chord Length
chord_length = wing_area / wing_span
print("Main Wing Chord Length %0.4f ft" % chord_length)

# Fuselage Length
fuselage_length = 0.86 * imperial_estimates[-1]**0.48
print("Fuselage Length %0.4f ft" % fuselage_length)

# Tail Positioning (Moment arm)
tail_poisitioning = fuselage_length * 0.65
print("Tail Positioning (Moment arm location) %0.4f ft" % tail_poisitioning)

# Tail Dimensions