import matplotlib.pyplot as plt
from matplotlib.patches import Patch
import numpy as np
from scipy.interpolate import make_interp_spline

# 1. Original Data (Skin Corrosion H314)
bin_centers = [0.0, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.0]
frequencies = [15.78, 21.80, 10.76, 6.84, 5.34, 5.14, 3.96, 2.55, 2.95, 3.16, 3.44, 2.43, 2.55, 1.90, 2.10, 1.86, 1.33, 1.86, 1.25, 2.47, 0.53]

# 2. Generate the smoothed curve (Spline)
x_smooth = np.linspace(min(bin_centers), max(bin_centers), 300)
spl = make_interp_spline(bin_centers, frequencies, k=3)
y_smooth = spl(x_smooth)
y_smooth = [val if val > 0 else 0 for val in y_smooth] 

# 3. Colors (Green < 0.3, Intermediate Gold, Red > 0.8)
colors = []
for val in bin_centers:
    if val < 0.3:
        colors.append('green')      # Skin Safe
    elif val < 0.8:
        colors.append('gold')       # Warning / Irritant
    else:
        colors.append('firebrick')  # Corrosive Hazard (H314)

# 4. Create the chart
plt.figure(figsize=(7, 6))

# Bars
plt.bar(bin_centers, frequencies, width=0.04, color=colors, edgecolor='black', alpha=0.6, label='Observed Data')

# 5. Tags and Titles
plt.xlabel('Probability of Skin Corrosion (H314)', fontsize=12)
plt.ylabel('% Frequency', fontsize=12)
plt.title('Skin Corrosion Distribution', fontsize=14)

# Axle settings
plt.xticks(np.arange(0.0, 1.05, 0.1))
plt.xlim(-0.05, 1.05)
plt.ylim(0, 25)

# 6. Legend
legend_elements = [
    Patch(facecolor='green', edgecolor='black', label='Safe (Non-Corrosive)'),
    Patch(facecolor='gold', edgecolor='black', label='Potential Irritant'),
    Patch(facecolor='firebrick', edgecolor='black', label='Corrosive Hazard'),
]

plt.legend(handles=legend_elements, loc='upper right', framealpha=0.95, fontsize=10)

plt.grid(axis='y', linestyle='--', alpha=0.5)
plt.tight_layout()

plt.show()