# pyright: basic

from __future__ import annotations

from pathlib import Path

import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
import torch
from matplotlib.axes import Axes

# Easily editable plot text overrides by plot key.
# Example:
# "performance_threshold": {
#     "title": "Custom Title",
#     "x_label": "Custom X",
#     "y_label": "Custom Y",
# }
# Common keys:
# - performance_threshold_accuracy
# - performance_threshold_f1
# - performance_uncertainty_cutoff_accuracy
# - performance_uncertainty_cutoff_f1
# - performance_uncertainty_percentile_cutoff_accuracy
# - performance_uncertainty_percentile_cutoff_f1
# - calibration_reliability
# - noise_sensitivity_accuracy
# - noise_sensitivity_f1
# - noise_confidence
# - noise_standard_deviation
# - noise_predictive_uncertainty
# - boxplot
PLOT_TEXT_OVERRIDES: dict[str, dict[str, str]] = {}


def _resolve_plot_text(
    plot_key: str,
    default_title: str,
    default_x_label: str,
    default_y_label: str,
) -> tuple[str, str, str]:
    override = PLOT_TEXT_OVERRIDES.get(plot_key, {})
    return (
        override.get("title", default_title),
        override.get("x_label", default_x_label),
        override.get("y_label", default_y_label),
    )


def annotate_stats_box(
    ax: Axes,
    lines: list[str],
    location: str = "upper left",
) -> None:
    if not lines:
        return

    locations: dict[str, tuple[float, float, str, str]] = {
        "upper left": (0.02, 0.98, "left", "top"),
        "upper right": (0.98, 0.98, "right", "top"),
        "lower left": (0.02, 0.02, "left", "bottom"),
        "lower right": (0.98, 0.02, "right", "bottom"),
    }
    x, y, ha, va = locations.get(location, locations["upper left"])
    ax.text(
        x,
        y,
        "\n".join(lines),
        transform=ax.transAxes,
        ha=ha,
        va=va,
        fontsize=10,
        bbox={
            "boxstyle": "round,pad=0.35",
            "facecolor": "white",
            "edgecolor": "#555555",
            "alpha": 0.9,
        },
    )


def _plot_correct_incorrect_bars(
    ax: Axes,
    x_values: pd.Series,
    n_correct: pd.Series,
    n_incorrect: pd.Series,
) -> None:
    x = np.asarray(x_values, dtype=float)
    correct = np.asarray(n_correct, dtype=float)
    incorrect = np.asarray(n_incorrect, dtype=float)
    if x.size == 0 or correct.size == 0 or incorrect.size == 0:
        return

    width = float(np.diff(np.sort(x)).min()) * 0.8 if x.size > 1 else 0.04
    max_count = float(max(np.nanmax(correct), np.nanmax(incorrect), 1.0))

    bars_ax = ax.twinx()
    bars_ax.patch.set_alpha(0.0)
    bars_ax.bar(
        x,
        correct,
        width=width,
        color="#2ca02c",
        alpha=0.2,
        label="correct",
        zorder=0,
        align="center",
    )
    bars_ax.bar(
        x,
        -incorrect,
        width=width,
        color="#d62728",
        alpha=0.2,
        label="incorrect",
        zorder=0,
        align="center",
    )
    bars_ax.axhline(0.0, color="gray", linewidth=0.8, alpha=0.4)
    bars_ax.set_ylim(-1.15 * max_count, 1.15 * max_count)
    bars_ax.set_yticks([])
    bars_ax.grid(False)


def save_coverage_bar_plot(
    x_values: pd.Series | np.ndarray,
    n_correct: pd.Series | np.ndarray,
    n_incorrect: pd.Series | np.ndarray,
    x_label: str,
    title: str,
    output_path: Path,
) -> None:
    """Save a standalone bar chart showing sample counts (correct vs incorrect)."""
    x = np.asarray(x_values, dtype=float)
    correct = np.asarray(n_correct, dtype=float)
    incorrect = np.asarray(n_incorrect, dtype=float)
    if x.size == 0 or correct.size == 0 or incorrect.size == 0:
        return

    width = float(np.diff(np.sort(x)).min()) * 0.8 if x.size > 1 else 0.04
    max_count = float(max(np.nanmax(correct), np.nanmax(incorrect), 1.0))

    fig, ax = plt.subplots(figsize=(10, 5))
    ax.bar(
        x,
        correct,
        width=width,
        color="#2ca02c",
        alpha=0.6,
        label="correct",
        align="center",
    )
    ax.bar(
        x,
        -incorrect,
        width=width,
        color="#d62728",
        alpha=0.6,
        label="incorrect",
        align="center",
    )
    ax.axhline(0.0, color="gray", linewidth=0.8, alpha=0.4)
    ax.set_ylim(-1.15 * max_count, 1.15 * max_count)
    ax.set_xlabel(x_label)
    ax.set_ylabel("Sample Count")
    ax.set_title(title)
    ax.legend()
    ax.grid(True, alpha=0.3)
    fig.tight_layout()
    output_path.parent.mkdir(parents=True, exist_ok=True)
    fig.savefig(output_path)
    plt.close(fig)


def plots_dir(output_dir: Path) -> Path:
    plots = output_dir / "plots"
    plots.mkdir(parents=True, exist_ok=True)
    return plots


def save_performance_threshold_plot(
    df: pd.DataFrame,
    backend: str,
    output_path: Path,
    metric_column: str,
    metric_label: str,
    plot_key: str,
) -> None:
    title, x_label, y_label = _resolve_plot_text(
        plot_key=plot_key,
        default_title=f"{metric_label} vs Decision Threshold ({backend})",
        default_x_label="Decision Threshold",
        default_y_label=metric_label,
    )

    n_correct = pd.to_numeric(df["tp"], errors="coerce") + pd.to_numeric(
        df["tn"], errors="coerce"
    )
    n_incorrect = pd.to_numeric(df["fp"], errors="coerce") + pd.to_numeric(
        df["fn"], errors="coerce"
    )

    fig, ax = plt.subplots(figsize=(10, 5))
    ax.plot(df["threshold"], df[metric_column], label=metric_label, marker="o")
    ax.set_xlabel(x_label)
    ax.set_ylabel(y_label)
    ax.set_title(title)
    ax.grid(True, alpha=0.3)
    ax.legend()
    fig.tight_layout()
    output_path.parent.mkdir(parents=True, exist_ok=True)
    fig.savefig(output_path)
    plt.close(fig)

    # Generate separate coverage bar plot
    coverage_path = output_path.parent / f"{output_path.stem}_coverage.png"
    save_coverage_bar_plot(
        x_values=df["threshold"],
        n_correct=n_correct,
        n_incorrect=n_incorrect,
        x_label=x_label,
        title=f"Sample Distribution vs Decision Threshold ({backend})",
        output_path=coverage_path,
    )


def save_performance_threshold_pair_plot(
    df: pd.DataFrame,
    backend: str,
    output_path: Path,
    plot_key: str,
) -> None:
    title, x_label, _ = _resolve_plot_text(
        plot_key=plot_key,
        default_title=f"Accuracy and F1 vs Decision Threshold ({backend})",
        default_x_label="Decision Threshold",
        default_y_label="Accuracy/F1",
    )

    n_correct = pd.to_numeric(df["tp"], errors="coerce") + pd.to_numeric(
        df["tn"], errors="coerce"
    )
    n_incorrect = pd.to_numeric(df["fp"], errors="coerce") + pd.to_numeric(
        df["fn"], errors="coerce"
    )

    fig, axes = plt.subplots(1, 2, figsize=(14, 5), sharex=True)
    for ax, metric_col, metric_label, marker in [
        (axes[0], "accuracy", "Accuracy", "o"),
        (axes[1], "f1", "F1", "s"),
    ]:
        ax.plot(df["threshold"], df[metric_col], label=metric_label, marker=marker)
        ax.set_xlabel(x_label)
        ax.set_ylabel(metric_label)
        ax.set_title(f"{metric_label}")
        ax.grid(True, alpha=0.3)
        ax.legend()

    fig.suptitle(title)
    fig.tight_layout()
    output_path.parent.mkdir(parents=True, exist_ok=True)
    fig.savefig(output_path)
    plt.close(fig)

    # Generate separate coverage bar plot
    coverage_path = output_path.parent / f"{output_path.stem}_coverage.png"
    save_coverage_bar_plot(
        x_values=df["threshold"],
        n_correct=n_correct,
        n_incorrect=n_incorrect,
        x_label=x_label,
        title=f"Sample Distribution vs Decision Threshold ({backend})",
        output_path=coverage_path,
    )


def save_uncertainty_cutoff_plot(
    cutoff_df: pd.DataFrame,
    title_prefix: str,
    x_label: str,
    output_path: Path,
    metric_column: str,
    metric_label: str,
    plot_key: str,
) -> None:
    title, x_label_final, y_label = _resolve_plot_text(
        plot_key=plot_key,
        default_title=f"{metric_label} vs {title_prefix}",
        default_x_label=x_label,
        default_y_label=metric_label,
    )

    fig, ax = plt.subplots(figsize=(10, 5))

    for uncertainty_name, group in cutoff_df.groupby("uncertainty_type"):
        g = group.sort_values("restriction_level")
        ax.plot(
            g["restriction_level"],
            g[metric_column],
            marker="o",
            label=uncertainty_name,
        )

    ax.set_title(title)
    ax.set_xlabel(x_label_final)
    ax.set_ylabel(y_label)
    ax.grid(True, alpha=0.3)
    ax.legend()
    fig.tight_layout()
    output_path.parent.mkdir(parents=True, exist_ok=True)
    fig.savefig(output_path)
    plt.close(fig)

    # Generate separate coverage bar plot
    first_group = (
        cutoff_df.sort_values(["uncertainty_type", "restriction_level"])
        .groupby("uncertainty_type", as_index=False)
        .head(1)
    )
    if not first_group.empty:
        rep_name = str(first_group.iloc[0]["uncertainty_type"])
        rep = cutoff_df[cutoff_df["uncertainty_type"] == rep_name].sort_values(
            "restriction_level"
        )
        coverage_path = output_path.parent / f"{output_path.stem}_coverage.png"
        save_coverage_bar_plot(
            x_values=rep["restriction_level"],
            n_correct=pd.to_numeric(rep["n_correct"], errors="coerce"),
            n_incorrect=pd.to_numeric(rep["n_incorrect"], errors="coerce"),
            x_label=x_label_final,
            title=f"Sample Coverage vs {title_prefix}",
            output_path=coverage_path,
        )


def save_uncertainty_cutoff_pair_plot(
    cutoff_df: pd.DataFrame,
    title_prefix: str,
    x_label: str,
    output_path: Path,
    plot_key: str,
) -> None:
    title, x_label_final, _ = _resolve_plot_text(
        plot_key=plot_key,
        default_title=f"Accuracy and F1 vs {title_prefix}",
        default_x_label=x_label,
        default_y_label="Accuracy/F1",
    )

    fig, axes = plt.subplots(1, 2, figsize=(14, 5), sharex=True)

    for uncertainty_name, group in cutoff_df.groupby("uncertainty_type"):
        g = group.sort_values("restriction_level")
        axes[0].plot(
            g["restriction_level"], g["accuracy"], marker="o", label=uncertainty_name
        )
        axes[1].plot(
            g["restriction_level"], g["f1"], marker="s", label=uncertainty_name
        )

    axes[0].set_title("Accuracy")
    axes[1].set_title("F1")
    for ax, metric_label in [(axes[0], "Accuracy"), (axes[1], "F1")]:
        ax.set_xlabel(x_label_final)
        ax.set_ylabel(metric_label)
        ax.grid(True, alpha=0.3)
        ax.legend()

    fig.suptitle(title)
    fig.tight_layout()
    output_path.parent.mkdir(parents=True, exist_ok=True)
    fig.savefig(output_path)
    plt.close(fig)

    # Generate separate coverage bar plot
    first_group = (
        cutoff_df.sort_values(["uncertainty_type", "restriction_level"])
        .groupby("uncertainty_type", as_index=False)
        .head(1)
    )
    if not first_group.empty:
        rep_name = str(first_group.iloc[0]["uncertainty_type"])
        rep = cutoff_df[cutoff_df["uncertainty_type"] == rep_name].sort_values(
            "restriction_level"
        )
        coverage_path = output_path.parent / f"{output_path.stem}_coverage.png"
        save_coverage_bar_plot(
            x_values=rep["restriction_level"],
            n_correct=pd.to_numeric(rep["n_correct"], errors="coerce"),
            n_incorrect=pd.to_numeric(rep["n_incorrect"], errors="coerce"),
            x_label=x_label_final,
            title=f"Sample Coverage vs {title_prefix}",
            output_path=coverage_path,
        )


def save_calibration_plot(per_bin: np.ndarray, backend: str, output_path: Path) -> None:
    title, x_label, y_label = _resolve_plot_text(
        plot_key="calibration_reliability",
        default_title=f"Reliability Diagram ({backend})",
        default_x_label="Mean Predicted Probability",
        default_y_label="Empirical Fraction Positive",
    )

    fig, ax = plt.subplots(figsize=(6, 6))
    valid = ~np.isnan(per_bin[:, 1])
    ax.plot([0, 1], [0, 1], linestyle="--", color="gray", label="ideal")
    ax.plot(per_bin[valid, 0], per_bin[valid, 1], marker="o", label=backend)
    ax.set_xlabel(x_label)
    ax.set_ylabel(y_label)
    ax.set_title(title)
    ax.legend()
    ax.grid(True, alpha=0.3)
    fig.tight_layout()
    output_path.parent.mkdir(parents=True, exist_ok=True)
    fig.savefig(output_path)
    plt.close(fig)


def save_boxplot(
    data: list[np.ndarray],
    tick_labels: list[str],
    x_label: str,
    y_label: str,
    title: str,
    output_path: Path,
) -> None:
    title_final, x_label_final, y_label_final = _resolve_plot_text(
        plot_key="boxplot",
        default_title=title,
        default_x_label=x_label,
        default_y_label=y_label,
    )

    labels_with_n = [
        f"{label}\n(n={len(np.asarray(values, dtype=float))})"
        for label, values in zip(tick_labels, data)
    ]

    fig, ax = plt.subplots(figsize=(9, 5))
    ax.boxplot(data, tick_labels=labels_with_n)
    ax.set_xlabel(x_label_final)
    ax.set_ylabel(y_label_final)
    ax.set_title(title_final)
    ax.grid(True, axis="y", alpha=0.3)
    fig.tight_layout()
    output_path.parent.mkdir(parents=True, exist_ok=True)
    fig.savefig(output_path)
    plt.close(fig)


def _central_slice(volume: torch.Tensor) -> np.ndarray:
    tensor = volume.detach().cpu()
    if tensor.ndim == 5:
        tensor = tensor[0]
    if tensor.ndim == 4:
        tensor = tensor[0]
    if tensor.ndim != 3:
        raise ValueError(
            f"Expected a 3D volume after squeezing batch/channel, got shape {tuple(tensor.shape)}"
        )

    center_index = tensor.shape[0] // 2
    return tensor[center_index].numpy().astype(float)


def _normalize_for_display(image: np.ndarray) -> np.ndarray:
    low = float(np.percentile(image, 1))
    high = float(np.percentile(image, 99))
    if high <= low:
        return np.zeros_like(image, dtype=float)
    clipped = np.clip(image, low, high)
    return (clipped - low) / (high - low)


def save_noise_example_grid(
    original_mri: torch.Tensor,
    noisy_by_sigma: list[tuple[float, torch.Tensor]],
    output_path: Path,
    title: str,
    max_images: int = 9,
    n_rows: int = 2,
) -> None:
    if not noisy_by_sigma:
        return

    n_total = len(noisy_by_sigma)
    target = max(1, min(int(max_images), n_total))
    if target >= n_total:
        selected = noisy_by_sigma
    else:
        # Sample indices across the full tested range, including first and last.
        raw_idx = np.linspace(0, n_total - 1, num=target)
        idx = np.round(raw_idx).astype(int)
        selected_indices = sorted(set(idx.tolist()))
        if len(selected_indices) < target:
            existing = set(selected_indices)
            for i in range(n_total):
                if i in existing:
                    continue
                selected_indices.append(i)
                if len(selected_indices) >= target:
                    break
            selected_indices = sorted(selected_indices)

        selected = [noisy_by_sigma[i] for i in selected_indices]

    n_images = len(selected)
    n_rows = max(1, int(n_rows))
    n_cols = int(np.ceil(n_images / n_rows))

    fig, axes = plt.subplots(n_rows, n_cols, figsize=(3.8 * n_cols, 3.2 * n_rows))
    axes_flat = np.atleast_1d(axes).reshape(-1)

    for idx, (sigma, noisy_tensor) in enumerate(selected):
        ax = axes_flat[idx]
        noisy_slice = _normalize_for_display(_central_slice(noisy_tensor))
        ax.imshow(noisy_slice, cmap="gray")
        ax.set_title(f"Noise factor={sigma:g}")
        ax.axis("off")

    for idx in range(n_images, len(axes_flat)):
        axes_flat[idx].axis("off")

    fig.suptitle(title)
    fig.tight_layout()
    output_path.parent.mkdir(parents=True, exist_ok=True)
    fig.savefig(output_path)
    plt.close(fig)


def save_clean_scan_image(
    original_mri: torch.Tensor,
    output_path: Path,
) -> None:
    image = _normalize_for_display(_central_slice(original_mri))
    fig, ax = plt.subplots(figsize=(4, 4))
    ax.imshow(image, cmap="gray")
    ax.axis("off")
    fig.subplots_adjust(left=0, right=1, top=1, bottom=0)
    output_path.parent.mkdir(parents=True, exist_ok=True)
    fig.savefig(output_path, bbox_inches="tight", pad_inches=0)
    plt.close(fig)


def save_noise_metrics_plot(
    x: pd.Series,
    y: pd.Series,
    legend_label: str,
    marker: str,
    x_label: str,
    y_label: str,
    title: str,
    output_path: Path,
    plot_key: str,
) -> None:
    title_final, x_label_final, y_label_final = _resolve_plot_text(
        plot_key=plot_key,
        default_title=title,
        default_x_label=x_label,
        default_y_label=y_label,
    )

    fig, ax = plt.subplots(figsize=(10, 5))
    ax.plot(x, y, marker=marker, label=legend_label)
    ax.set_xlabel(x_label_final)
    ax.set_ylabel(y_label_final)
    ax.set_title(title_final)
    ax.grid(True, alpha=0.3)
    ax.legend()
    fig.tight_layout()
    output_path.parent.mkdir(parents=True, exist_ok=True)
    fig.savefig(output_path)
    plt.close(fig)


def save_metric_pair_plot(
    x: pd.Series,
    left_y: pd.Series,
    right_y: pd.Series,
    left_label: str,
    right_label: str,
    x_label: str,
    y_label: str,
    title: str,
    output_path: Path,
    plot_key: str,
) -> None:
    title_final, x_label_final, y_label_final = _resolve_plot_text(
        plot_key=plot_key,
        default_title=title,
        default_x_label=x_label,
        default_y_label=y_label,
    )

    fig, axes = plt.subplots(1, 2, figsize=(14, 5), sharex=True)
    axes[0].plot(x, left_y, marker="o", label=left_label)
    axes[1].plot(x, right_y, marker="s", label=right_label)

    for ax, name in [(axes[0], left_label), (axes[1], right_label)]:
        ax.set_xlabel(x_label_final)
        ax.set_ylabel(name)
        ax.set_title(name)
        ax.grid(True, alpha=0.3)
        ax.legend()

    fig.suptitle(title_final)
    fig.tight_layout()
    output_path.parent.mkdir(parents=True, exist_ok=True)
    fig.savefig(output_path)
    plt.close(fig)