"""LitCoder-style fsaverage5 surface plotting helpers."""

from __future__ import annotations

import os
import warnings
from io import BytesIO
from pathlib import Path
from typing import Any

import numpy as np

DEFAULT_SCRATCH_ROOT = Path(os.environ.get("BRAINENCODING_SCRATCH_ROOT", "/storage/scratch1/8/whuang409"))
DEFAULT_FSAVERAGE5 = Path("/storage/project/r-aivanova7-0/shared/.env/freesurfer/subjects/fsaverage5")
N_HEMI = 10242
N_VERTICES = 20484

os.environ.setdefault("MPLCONFIGDIR", str(DEFAULT_SCRATCH_ROOT / "matplotlib"))
import matplotlib  # noqa: E402

matplotlib.use("Agg")
import matplotlib.pyplot as plt  # noqa: E402
from matplotlib.colors import Normalize  # noqa: E402


def save_litcoder_style_map(
    values: np.ndarray,
    output_path: Path,
    *,
    title: str,
    fsaverage5: Path = DEFAULT_FSAVERAGE5,
    significant_mask: np.ndarray | None = None,
    positive: bool = False,
    mask_zero: bool = True,
    vmax: float | None = None,
    cmap: str | Any | None = None,
    dpi: int = 150,
) -> None:
    fig = plot_litcoder_style_map(
        values,
        title=title,
        fsaverage5=fsaverage5,
        significant_mask=significant_mask,
        positive=positive,
        mask_zero=mask_zero,
        vmax=vmax,
        cmap=cmap,
    )
    output_path.parent.mkdir(parents=True, exist_ok=True)
    fig.savefig(output_path, format="png", bbox_inches="tight", dpi=dpi)
    plt.close(fig)


def litcoder_style_png_bytes(
    values: np.ndarray,
    *,
    title: str,
    fsaverage5: Path = DEFAULT_FSAVERAGE5,
    significant_mask: np.ndarray | None = None,
    positive: bool = False,
    mask_zero: bool = True,
    vmax: float | None = None,
    cmap: str | Any | None = None,
    dpi: int = 130,
) -> bytes:
    fig = plot_litcoder_style_map(
        values,
        title=title,
        fsaverage5=fsaverage5,
        significant_mask=significant_mask,
        positive=positive,
        mask_zero=mask_zero,
        vmax=vmax,
        cmap=cmap,
    )
    buffer = BytesIO()
    fig.savefig(buffer, format="png", bbox_inches="tight", dpi=dpi)
    plt.close(fig)
    return buffer.getvalue()


def plot_litcoder_style_map(
    values: np.ndarray,
    *,
    title: str,
    fsaverage5: Path = DEFAULT_FSAVERAGE5,
    significant_mask: np.ndarray | None = None,
    positive: bool = False,
    mask_zero: bool = True,
    vmax: float | None = None,
    cmap: str | Any | None = None,
) -> plt.Figure:
    """Plot a 20484-vector in the LitCoder four-panel fsaverage5 layout."""
    from nilearn import plotting
    from nilearn.plotting.cm import cold_hot

    display_values = prepare_values(
        values,
        significant_mask=significant_mask,
        positive=positive,
        mask_zero=mask_zero,
    )
    vmax = value_limit(display_values, vmax=vmax, positive=positive)
    vmin = 0.0 if positive else -vmax
    cmap = cmap or ("viridis" if positive else cold_hot)
    norm = Normalize(vmin=vmin, vmax=vmax)

    fsaverage5 = Path(fsaverage5)
    meshes = {
        "lh": fsaverage5 / "surf" / "lh.inflated",
        "rh": fsaverage5 / "surf" / "rh.inflated",
    }
    for path in meshes.values():
        if not path.exists():
            raise FileNotFoundError(f"Missing fsaverage5 surface mesh: {path}")

    fig = plt.figure(figsize=(15, 10))
    views = [
        ("lh", "left", "lateral", 231, "Left Lateral"),
        ("lh", "left", "medial", 232, "Left Medial"),
        ("rh", "right", "lateral", 234, "Right Lateral"),
        ("rh", "right", "medial", 235, "Right Medial"),
    ]
    for hemi_key, hemi_name, view, subplot, pane_title in views:
        hemi_values = display_values[:N_HEMI] if hemi_key == "lh" else display_values[N_HEMI:]
        ax = fig.add_subplot(subplot, projection="3d")
        with warnings.catch_warnings():
            warnings.filterwarnings("ignore", message="All-NaN slice encountered", category=RuntimeWarning)
            plotting.plot_surf_stat_map(
                str(meshes[hemi_key]),
                hemi_values,
                hemi=hemi_name,
                view=view,
                colorbar=False,
                axes=ax,
                cmap=cmap,
                vmin=vmin,
                vmax=vmax,
                title=pane_title,
            )

    sm = plt.cm.ScalarMappable(norm=norm, cmap=cmap)
    sm.set_array([])
    cax = fig.add_axes([0.92, 0.15, 0.02, 0.7])
    fig.colorbar(sm, cax=cax)
    fig.suptitle(title, fontsize=16)
    with warnings.catch_warnings():
        warnings.filterwarnings("ignore", message="This figure includes Axes that are not compatible with tight_layout.*")
        fig.tight_layout(rect=[0.03, 0.03, 0.9, 0.97])
    return fig


def prepare_values(
    values: np.ndarray,
    *,
    significant_mask: np.ndarray | None,
    positive: bool,
    mask_zero: bool,
) -> np.ndarray:
    out = np.asarray(values, dtype=np.float32).reshape(-1).copy()
    if out.shape != (N_VERTICES,):
        raise ValueError(f"Expected {(N_VERTICES,)} values, got {out.shape}")
    shown = np.isfinite(out)
    if significant_mask is not None:
        mask = np.asarray(significant_mask, dtype=bool).reshape(-1)
        if mask.shape != (N_VERTICES,):
            raise ValueError(f"Expected {(N_VERTICES,)} mask values, got {mask.shape}")
        shown &= mask
    if mask_zero:
        shown &= (out > 0.0) if positive else (np.abs(out) > 0.0)
    out[~shown] = np.nan
    return out


def value_limit(values: np.ndarray, *, vmax: float | None, positive: bool) -> float:
    if vmax is not None and np.isfinite(vmax) and vmax > 0:
        return float(vmax)
    finite = values[np.isfinite(values)]
    if finite.size == 0:
        return 1.0
    finite = finite[finite > 0.0] if positive else np.abs(finite)
    if finite.size == 0:
        return 1.0
    limit = float(np.nanmax(finite))
    return limit if np.isfinite(limit) and limit > 0 else 1.0