import csv
import argparse
import matplotlib.pyplot as plt
from matplotlib.lines import Line2D

K = 1.0
BOUNDARY_EPS = 0.02


def load_csv(path):
    with open(path, newline="", encoding="utf-8") as f:
        return list(csv.DictReader(f))


def index_by_id(rows):
    index = {}
    for row in rows:
        sid = str(row.get("scenario_id", "")).strip()
        if not sid:
            raise ValueError("Blank or missing scenario_id detected")
        if sid in index:
            raise ValueError(f"Duplicate scenario_id detected: {sid}")
        index[sid] = row
    return index


def parse_binary(value, field_name, sid):
    try:
        parsed = int(value)
    except ValueError as e:
        raise ValueError(f"Invalid {field_name} for {sid}: {value}") from e
    if parsed not in (0, 1):
        raise ValueError(f"Invalid {field_name} for {sid}: {parsed}")
    return parsed


def compute_surfaces(pressure, buffer, lag, coupling):
    s1 = buffer - (pressure * coupling) - (K * lag)
    s2 = buffer - (pressure * (coupling ** 2)) - (K * lag)
    s3 = buffer - (pressure * coupling) - (K * (lag ** 2))
    return {
        "baseline_surface": s1,
        "coupling_surface": s2,
        "lag_surface": s3,
    }


def plot_projection(pred_path, truth_path):
    preds = load_csv(pred_path)
    truth = load_csv(truth_path)

    pred_map = index_by_id(preds)
    truth_map = index_by_id(truth)

    if set(pred_map.keys()) != set(truth_map.keys()):
        raise ValueError("scenario_id mismatch between prediction and truth files")

    plt.figure(figsize=(10, 8))

    for sid in sorted(truth_map):
        truth_row = truth_map[sid]
        pred_row = pred_map[sid]

        pressure = float(truth_row["pressure"])
        buffer = float(truth_row["buffer"])
        lag = float(truth_row["lag"])
        coupling = float(truth_row["coupling"])

        pred = parse_binary(pred_row["prediction"], "prediction", sid)
        label = parse_binary(truth_row["label_stable"], "label_stable", sid)

        surfaces = compute_surfaces(pressure, buffer, lag, coupling)
        manifold_margin = min(surfaces.values())
        active_surface = min(surfaces, key=surfaces.get)

        x = pressure * coupling
        y = buffer

        if abs(manifold_margin) <= BOUNDARY_EPS:
            color = "orange"
            marker = "s"
        elif manifold_margin < 0:
            color = "red"
            marker = "x"
        else:
            color = "green"
            marker = "o"

        if label == 0 and pred == 1:
            color = "purple"
            marker = "*"
        elif label == 1 and pred == 0:
            color = "blue"
            marker = "D"

        size = 110
        edgecolor = "black" if active_surface == "coupling_surface" else "none"
        linewidth = 1.2 if active_surface == "coupling_surface" else 0.0

        plt.scatter(
            x,
            y,
            c=color,
            marker=marker,
            s=size,
            edgecolors=edgecolor,
            linewidths=linewidth,
        )

    plt.xlabel("Pressure × Coupling")
    plt.ylabel("Buffer Capacity")
    plt.title("Clarus Stability Manifold Projection (2D View)")
    plt.grid(True)
    plt.tight_layout()

    legend_elements = [
        Line2D([0], [0], marker="o", color="w", label="Stable region", markerfacecolor="green", markersize=10),
        Line2D([0], [0], marker="x", color="red", label="Collapse region", linestyle="None", markersize=10),
        Line2D([0], [0], marker="s", color="w", label="Near boundary", markerfacecolor="orange", markersize=10),
        Line2D([0], [0], marker="*", color="w", label="False rescue", markerfacecolor="purple", markersize=12),
        Line2D([0], [0], marker="D", color="w", label="False collapse", markerfacecolor="blue", markersize=10),
        Line2D([0], [0], marker="o", color="black", label="Coupling surface active", markerfacecolor="white", markersize=9),
    ]
    plt.legend(handles=legend_elements)
    plt.show()


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("--pred", required=True)
    parser.add_argument("--truth", required=True)
    args = parser.parse_args()

    plot_projection(args.pred, args.truth)