"""Plot VSL action heatmaps from exported evaluation CSV files."""
import os

import matplotlib
import matplotlib.pyplot as plt
import numpy as np
import pandas as pd

matplotlib.use("Agg")

OUTPUT_DIR = "evaluation_results"
MODEL_LABELS = ["PPO", "APPO", "DQN", "No Control"]
MODEL_FILE_ALIASES = {
    "PPO": ["PPO"],
    "APPO": ["APPO"],
    "DQN": ["DQN"],
    "No Control": ["No Control"],
}
SPEED_MAP = [40, 60, 80, 100, 120]


def resolve_csv_path(model_label: str) -> str:
    for file_stem in MODEL_FILE_ALIASES[model_label]:
        candidate = os.path.join(OUTPUT_DIR, f"{file_stem}_action.csv")
        if os.path.isfile(candidate):
            return candidate
    raise FileNotFoundError(f"Missing action CSV for {model_label} under {OUTPUT_DIR}")


fig, axes = plt.subplots(2, 2, figsize=(16, 12))
axes = axes.flatten()

for idx, model_label in enumerate(MODEL_LABELS):
    csv_path = resolve_csv_path(model_label)
    df = pd.read_csv(csv_path)
    actions = df.values
    vsl_speeds = np.vectorize(lambda action_idx: SPEED_MAP[int(action_idx)])(actions)

    im = axes[idx].imshow(
        vsl_speeds.T,
        aspect="auto",
        cmap="RdYlGn",
        vmin=40,
        vmax=120,
        origin="lower",
    )
    axes[idx].set_title(f"{model_label} VSL Decision")
    axes[idx].set_xlabel("Time Step")
    axes[idx].set_ylabel("Control Edge Index")
    cbar = plt.colorbar(im, ax=axes[idx], label="VSL (km/h)")
    cbar.set_ticks([40, 60, 80, 100, 120])

plt.tight_layout()
plt.savefig(os.path.join(OUTPUT_DIR, "action_heatmaps.png"), dpi=150)
print("Saved action heatmaps.")