import matplotlib.pyplot as plt
import matplotlib.colors as mcolors
from matplotlib.patches import Patch
import numpy as np
from scipy.interpolate import PchipInterpolator

# 1. Original Data (Aquatic Toxicity - P. subcapitata)
bins_eco = np.array([0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0])
freq_eco = np.array([0.93, 2.04, 3.18, 3.95, 3.86, 3.82, 3.52, 6.11, 6.16, 6.07, 5.48, 6.20, 7.26, 7.43, 6.50, 8.24, 7.60, 8.49, 3.14, 0.0])

# 2. Statistical Calculations
mean_val = np.average(bins_eco, weights=freq_eco)

# PCHIP interpolation to follow the asymmetric real shape of the data
interpolator = PchipInterpolator(bins_eco, freq_eco)
x_fit = np.linspace(0.05, 1.0, 500)
y_fit = interpolator(x_fit)
y_fit = np.clip(y_fit, 0, None)

# 3. Color Function (Ecotoxicity Traffic Light)
def get_colors(bins):
    return ['#008000' if b < 0.4 else '#FFD700' if b <= 0.7 else '#B22222' for b in bins]
colors_hex = get_colors(bins_eco)
face_colors = [mcolors.to_rgba(c, alpha=0.60) for c in colors_hex]
edge_colors = [mcolors.to_rgba(c, alpha=0.90) for c in colors_hex]

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

# Draw bars and empirical curve
plt.bar(bins_eco, freq_eco, width=0.04, color=face_colors, edgecolor=edge_colors, linewidth=1.5, zorder=2)

# 5. Tags and Titles
plt.xlabel('Aquatic Toxicity Probability (P. subcapitata EC50 < 10 mg/L)', fontsize=12)
plt.ylabel('% Frequency', fontsize=12)
plt.title('Environmental Hazard: Algal Ecotoxicity (OECD 201)', fontsize=14)

# 6. Structured Legend
legend_elements = [
    Patch(facecolor=mcolors.to_rgba('#008000', 0.6), edgecolor='#008000', label='Low Ecotoxicity (< 0.4)'),
    Patch(facecolor=mcolors.to_rgba('#FFD700', 0.6), edgecolor='#FFD700', label='Moderate Hazard (0.4 - 0.7)'),
    Patch(facecolor=mcolors.to_rgba('#B22222', 0.6), edgecolor='#B22222', label='High Ecotoxicity (> 0.7)')
]
plt.legend(handles=legend_elements, loc='upper left', framealpha=0.95, fontsize=10)

plt.grid(axis='y', linestyle=':', alpha=0.7, zorder=0)
plt.xlim(0, 1.05)
plt.ylim(0, 10)
plt.tight_layout()

plt.show()