"""Streamlit 交互式结果展示界面。

运行：
    streamlit run app.py
"""

from __future__ import annotations

import json
from pathlib import Path
from typing import Dict, List, Sequence, Tuple

import matplotlib as mpl
import matplotlib.pyplot as plt
from matplotlib import font_manager
import numpy as np
import streamlit as st

from config import (
    CHECKPOINT_DIR,
    DEFAULT_CHECKPOINT,
    DEFAULT_FIXED_DICOM_DIR,
    DEFAULT_FIXED_NIFTI,
    DEFAULT_MOVING_DICOM_DIR,
    DEFAULT_MOVING_NIFTI,
    INFERENCE_DIR,
    NIFTI_DIR,
    OUTPUT_ROOT,
    PROJECT_ROOT,
)
from metrics import crop_to_common_shape, ddf_summary, registration_metrics, slice_metric_curve


st.set_page_config(
    page_title="VoxelMorph 颈部 CT 配准工作台",
    layout="wide",
    initial_sidebar_state="collapsed",
)


CUSTOM_CSS = """
<style>
  :root {
    --ink: #202124;
    --muted: #5f6368;
    --line: #d8dee4;
    --panel: #f6f8fa;
    --teal: #0f766e;
    --amber: #b45309;
  }
  .main .block-container {
    padding-top: 1.1rem;
    padding-bottom: 2rem;
    max-width: 1480px;
  }
  h1, h2, h3 {
    letter-spacing: 0;
  }
  div[data-testid="stMetric"] {
    border: 1px solid var(--line);
    border-radius: 6px;
    padding: 0.65rem 0.75rem;
    background: #ffffff;
  }
  section[data-testid="stSidebar"] {
    border-right: 1px solid var(--line);
  }
  .stTabs [data-baseweb="tab-list"] {
    gap: 8px;
    border-bottom: 1px solid var(--line);
  }
  .stTabs [data-baseweb="tab"] {
    border-radius: 0;
    padding-left: 4px;
    padding-right: 4px;
  }
</style>
"""


def configure_matplotlib_cjk_font() -> None:
    """配置 Matplotlib 中文字体。

    Streamlit 自身用浏览器字体渲染中文，通常没有问题；Matplotlib 图像会走
    后端字体管理，如果默认 DejaVu Sans 不含中文字形，就会显示成方块。
    """

    candidate_paths = [
        "/usr/share/fonts/opentype/noto/NotoSansCJK-Regular.ttc",
        "/usr/share/fonts/opentype/noto/NotoSansCJK-Bold.ttc",
        "/usr/share/fonts/truetype/droid/DroidSansFallbackFull.ttf",
    ]
    candidate_names = [
        "Noto Sans CJK SC",
        "Noto Sans CJK JP",
        "Droid Sans Fallback",
        "WenQuanYi Micro Hei",
        "Source Han Sans SC",
        "SimHei",
    ]

    discovered_names: List[str] = []
    for path_str in candidate_paths:
        path = Path(path_str)
        if not path.exists():
            continue
        try:
            font_manager.fontManager.addfont(str(path))
            discovered_names.append(font_manager.FontProperties(fname=str(path)).get_name())
        except Exception:
            continue

    mpl.rcParams["font.family"] = "sans-serif"
    mpl.rcParams["font.sans-serif"] = [*discovered_names, *candidate_names, "DejaVu Sans"]
    mpl.rcParams["axes.unicode_minus"] = False


configure_matplotlib_cjk_font()


def _require_nibabel():
    try:
        import nibabel as nib  # type: ignore
    except Exception as exc:
        raise RuntimeError("缺少 nibabel，请先运行: pip install -r requirements.txt") from exc
    return nib


def discover_nifti_files() -> List[str]:
    roots = [OUTPUT_ROOT, PROJECT_ROOT]
    paths: List[Path] = []
    for root in roots:
        if root.exists():
            paths.extend(root.rglob("*.nii"))
            paths.extend(root.rglob("*.nii.gz"))
    unique = sorted({str(path) for path in paths})
    return unique


def discover_checkpoint_files() -> List[str]:
    roots = [CHECKPOINT_DIR, OUTPUT_ROOT, PROJECT_ROOT]
    paths: List[Path] = []
    for root in roots:
        if root.exists():
            paths.extend(root.rglob("*.pt"))
            paths.extend(root.rglob("*.pth"))
            paths.extend(root.rglob("*.ckpt"))
    return sorted({str(path) for path in paths})


def choose_path(label: str, default_path: Path, candidates: Sequence[str]) -> str:
    options = ["手动输入"] + list(candidates)
    default_str = str(default_path)
    selected_index = options.index(default_str) if default_str in options else (1 if candidates else 0)
    selected = st.selectbox(label, options=options, index=selected_index)
    if selected == "手动输入":
        return st.text_input(f"{label}路径", value=default_str)
    return selected


@st.cache_data(max_entries=8, show_spinner=False)
def load_nifti_cached(path: str, max_voxels: int = 14_000_000) -> Tuple[np.ndarray, Tuple[float, float, float], int]:
    """为 Web 展示读取 NIfTI。

    Streamlit/浏览器端不适合一次渲染超大体数据。如果体素数过大，按等比例
    stride 下采样，只影响网页查看，不改变磁盘上的推理结果。
    """

    if not path:
        raise ValueError("路径为空。")
    nib = _require_nibabel()
    img = nib.load(path, mmap=True)
    if len(img.shape) > 4:
        raise ValueError(f"暂不支持超过 4D 的 NIfTI: {path}")

    spatial_shape = img.shape[:3]
    voxels = int(np.prod(spatial_shape))
    stride = max(1, int(np.ceil((voxels / max_voxels) ** (1.0 / 3.0)))) if voxels > max_voxels else 1
    spatial_slices = (slice(None, None, stride), slice(None, None, stride), slice(None, None, stride))

    if len(img.shape) == 4:
        data = np.array(img.dataobj[spatial_slices + (slice(None),)], dtype=np.float32, copy=True)
    else:
        data = np.array(img.dataobj[spatial_slices], dtype=np.float32, copy=True)
    data = np.nan_to_num(data, copy=False)
    spacing = tuple(float(v) * stride for v in img.header.get_zooms()[:3])
    return data, spacing, stride  # type: ignore[return-value]


def normalize_slice(image: np.ndarray, p_low: float = 1.0, p_high: float = 99.0) -> np.ndarray:
    image = image.astype(np.float32, copy=False)
    low, high = np.percentile(image, [p_low, p_high])
    if high <= low:
        return np.zeros_like(image, dtype=np.float32)
    return np.clip((image - low) / (high - low), 0.0, 1.0)


def orient_for_display(image: np.ndarray, plane: str) -> np.ndarray:
    """按平面统一显示方向。

    数组轴约定为 (X, Y, Z)，其中 Z 轴在当前患者1 DICOM 中从头侧到足侧
    递增。冠状面和矢状面应让 Z 轴作为屏幕竖直方向，避免头脚倒置。
    """

    if image.ndim == 3 and image.shape[-1] in (3, 4):
        return np.swapaxes(image, 0, 1)
    return image.T


def get_slice(volume_xyz: np.ndarray, plane: str, index: int) -> np.ndarray:
    if plane == "Axial":
        return volume_xyz[:, :, index]
    if plane == "Coronal":
        return volume_xyz[:, index, :]
    if plane == "Sagittal":
        return volume_xyz[index, :, :]
    raise ValueError(f"未知平面: {plane}")


def plane_axis(plane: str) -> int:
    return {"Sagittal": 0, "Coronal": 1, "Axial": 2}[plane]


def checkerboard(fixed_slice: np.ndarray, warped_slice: np.ndarray, tile: int = 24) -> np.ndarray:
    fixed_norm = normalize_slice(fixed_slice)
    warped_norm = normalize_slice(warped_slice)
    yy, xx = np.indices(fixed_norm.shape)
    mask = ((yy // tile + xx // tile) % 2).astype(bool)
    return np.where(mask, fixed_norm, warped_norm)


def gray_fusion(fixed_slice: np.ndarray, warped_slice: np.ndarray, alpha: float = 0.5) -> np.ndarray:
    fixed_norm = normalize_slice(fixed_slice)
    warped_norm = normalize_slice(warped_slice)
    return np.clip(fixed_norm * (1.0 - alpha) + warped_norm * alpha, 0.0, 1.0)


def color_difference_overlay(fixed_slice: np.ndarray, warped_slice: np.ndarray, alpha: float = 0.65) -> np.ndarray:
    fixed_norm = normalize_slice(fixed_slice)
    warped_norm = normalize_slice(warped_slice)
    base = fixed_norm * (1.0 - alpha) + warped_norm * alpha
    rgb = np.zeros((*fixed_norm.shape, 3), dtype=np.float32)
    rgb[..., 0] = np.maximum(base, warped_norm * alpha)
    rgb[..., 1] = base
    rgb[..., 2] = np.maximum(base, fixed_norm * alpha)
    return np.clip(rgb, 0.0, 1.0)


def signed_difference(fixed_slice: np.ndarray, warped_slice: np.ndarray) -> np.ndarray:
    fixed_norm = normalize_slice(fixed_slice)
    warped_norm = normalize_slice(warped_slice)
    return warped_norm - fixed_norm


def ddf_magnitude(ddf_xyz: np.ndarray) -> np.ndarray:
    if ddf_xyz.ndim != 4 or ddf_xyz.shape[-1] != 3:
        raise ValueError("DDF 应为 (X, Y, Z, 3)。")
    return np.linalg.norm(ddf_xyz.astype(np.float32, copy=False), axis=-1)


def ddf_color_limits(mag_xyz: np.ndarray, scale_mode: str) -> Tuple[float, float]:
    values = mag_xyz[np.isfinite(mag_xyz)]
    if values.size == 0:
        return 0.0, 1.0

    if scale_mode == "高位移增强":
        vmin, vmax = np.percentile(values, [50.0, 99.5])
    elif scale_mode == "绝对范围":
        vmin, vmax = np.min(values), np.max(values)
    else:
        vmin, vmax = np.percentile(values, [1.0, 99.0])

    vmin = float(vmin)
    vmax = float(vmax)
    if not np.isfinite(vmin) or not np.isfinite(vmax) or vmax <= vmin:
        vmax = vmin + 1e-6
    return vmin, vmax


def format_mm(value: float) -> str:
    value = float(value)
    if abs(value) < 0.01:
        return f"{value:.4f}"
    if abs(value) < 1.0:
        return f"{value:.3f}"
    return f"{value:.2f}"


def render_image(image: np.ndarray, caption: str, cmap: str = "gray", plane: str = "Axial") -> None:
    fig, ax = plt.subplots(figsize=(4.8, 4.8), dpi=120)
    ax.imshow(orient_for_display(image, plane), cmap=cmap, interpolation="nearest")
    ax.set_title(caption, fontsize=10)
    ax.axis("off")
    st.pyplot(fig, width="stretch")
    plt.close(fig)


def render_rgb(image: np.ndarray, caption: str, plane: str = "Axial") -> None:
    fig, ax = plt.subplots(figsize=(4.8, 4.8), dpi=120)
    ax.imshow(orient_for_display(image, plane), interpolation="nearest")
    ax.set_title(caption, fontsize=10)
    ax.axis("off")
    st.pyplot(fig, width="stretch")
    plt.close(fig)


def render_signed_difference(image: np.ndarray, caption: str, plane: str = "Axial") -> None:
    fig, ax = plt.subplots(figsize=(4.8, 4.8), dpi=120)
    diff = orient_for_display(image, plane)
    finite = diff[np.isfinite(diff)]
    vmax = float(np.percentile(np.abs(finite), 99.0)) if finite.size else 1.0
    vmax = max(vmax, 1e-6)
    im = ax.imshow(diff, cmap="coolwarm", vmin=-vmax, vmax=vmax, interpolation="nearest")
    ax.set_title(caption, fontsize=10)
    ax.axis("off")
    fig.colorbar(im, ax=ax, fraction=0.046, pad=0.02)
    st.pyplot(fig, width="stretch")
    plt.close(fig)


def render_heatmap_overlay(
    base_slice: np.ndarray,
    mag_slice: np.ndarray,
    alpha: float,
    caption: str,
    plane: str,
    vmin: float,
    vmax: float,
    show_base: bool,
) -> None:
    fig, ax = plt.subplots(figsize=(4.8, 4.8), dpi=120)
    if show_base:
        ax.imshow(orient_for_display(normalize_slice(base_slice), plane), cmap="gray", interpolation="nearest")
    heat = orient_for_display(mag_slice, plane)
    im = ax.imshow(
        heat,
        cmap="turbo",
        alpha=alpha if show_base else 1.0,
        interpolation="nearest",
        vmin=vmin,
        vmax=vmax,
    )
    ax.set_title(caption, fontsize=10)
    ax.axis("off")
    fig.colorbar(im, ax=ax, fraction=0.046, pad=0.02)
    st.pyplot(fig, width="stretch")
    plt.close(fig)


def render_three_views(volume_xyz: np.ndarray, title: str) -> None:
    st.subheader(title)
    columns = st.columns(3)
    planes = [("Axial", "轴状面"), ("Coronal", "冠状面"), ("Sagittal", "矢状面")]
    for col, (plane, cn_name) in zip(columns, planes):
        axis = plane_axis(plane)
        with col:
            index = st.slider(f"{cn_name}", 0, volume_xyz.shape[axis] - 1, volume_xyz.shape[axis] // 2, key=f"{title}-{plane}")
            render_image(get_slice(volume_xyz, plane, index), f"{cn_name} #{index}", plane=plane)


def render_three_way_views(fixed_xyz: np.ndarray, moving_xyz: np.ndarray, warped_xyz: np.ndarray | None) -> None:
    if warped_xyz is None:
        fixed_xyz, moving_xyz = crop_to_common_shape(fixed_xyz, moving_xyz)
        volumes = [("固定图像", fixed_xyz), ("移动图像", moving_xyz), ("配准后图像", None)]
        st.warning("尚未生成配准后图像。")
    else:
        fixed_xyz, moving_xyz, warped_xyz = crop_to_common_shape(fixed_xyz, moving_xyz, warped_xyz)
        volumes = [("固定图像", fixed_xyz), ("移动图像", moving_xyz), ("配准后图像", warped_xyz)]

    st.caption(f"显示尺寸：{fixed_xyz.shape[0]} x {fixed_xyz.shape[1]} x {fixed_xyz.shape[2]}")
    planes = [("Axial", "轴状面"), ("Coronal", "冠状面"), ("Sagittal", "矢状面")]
    for plane, cn_name in planes:
        axis = plane_axis(plane)
        index = st.slider(
            f"{cn_name}切片",
            0,
            fixed_xyz.shape[axis] - 1,
            fixed_xyz.shape[axis] // 2,
            key=f"three-way-{plane}",
        )
        st.markdown(f"#### {cn_name}")
        columns = st.columns(3)
        for col, (label, volume) in zip(columns, volumes):
            with col:
                if volume is None:
                    st.info("待生成")
                else:
                    render_image(get_slice(volume, plane, index), f"{label} #{index}", plane=plane)


def render_overlay_views(fixed_xyz: np.ndarray, warped_xyz: np.ndarray) -> None:
    fixed_xyz, warped_xyz = crop_to_common_shape(fixed_xyz, warped_xyz)
    mode = st.radio("对比模式", ["灰度融合", "红蓝差异", "差异热图", "棋盘格"], horizontal=True)
    if mode in {"灰度融合", "红蓝差异"}:
        alpha = st.slider("配准后图像权重", 0.0, 1.0, 0.5, 0.05)
    else:
        alpha = 0.5
    if mode == "棋盘格":
        tile = st.slider("棋盘格尺寸", 8, 64, 24, 4)
    else:
        tile = 24

    if mode == "红蓝差异":
        st.caption("红/金色偏向配准后图像，蓝色偏向固定图像；白灰区域表示两者灰度接近。")
    elif mode == "差异热图":
        st.caption("差异热图显示配准后图像减固定图像的灰度差，色条以当前切片的 99% 绝对差自动缩放。")

    columns = st.columns(3)
    planes = [("Axial", "轴状面"), ("Coronal", "冠状面"), ("Sagittal", "矢状面")]
    for col, (plane, cn_name) in zip(columns, planes):
        axis = plane_axis(plane)
        with col:
            index = st.slider(f"{cn_name}切片", 0, fixed_xyz.shape[axis] - 1, fixed_xyz.shape[axis] // 2, key=f"overlay-{plane}")
            fixed_slice = get_slice(fixed_xyz, plane, index)
            warped_slice = get_slice(warped_xyz, plane, index)
            if mode == "棋盘格":
                render_image(checkerboard(fixed_slice, warped_slice, tile=tile), f"{cn_name} 棋盘格 #{index}", plane=plane)
            elif mode == "红蓝差异":
                render_rgb(color_difference_overlay(fixed_slice, warped_slice, alpha=alpha), f"{cn_name} 红蓝差异 #{index}", plane=plane)
            elif mode == "差异热图":
                render_signed_difference(signed_difference(fixed_slice, warped_slice), f"{cn_name} 差异热图 #{index}", plane=plane)
            else:
                render_image(gray_fusion(fixed_slice, warped_slice, alpha=alpha), f"{cn_name} 灰度融合 #{index}", plane=plane)


def render_ddf_views(fixed_xyz: np.ndarray, ddf_xyz: np.ndarray) -> None:
    fixed_xyz, ddf_xyz = crop_to_common_shape(fixed_xyz, ddf_xyz)
    mag = ddf_magnitude(ddf_xyz)

    stats = ddf_summary(ddf_xyz)
    c1, c2, c3, c4 = st.columns(4)
    c1.metric("平均位移 mm", format_mm(stats["ddf_mean"]))
    c2.metric("P95 mm", format_mm(stats["ddf_p95"]))
    c3.metric("最大 mm", format_mm(stats["ddf_max"]))
    c4.metric("标准差", format_mm(stats["ddf_std"]))

    if stats["ddf_max"] < 0.1:
        st.info(f"当前最大位移只有 {format_mm(stats['ddf_max'])} mm，通常说明这是 smoke 权重或模型还没有充分训练。")

    controls = st.columns(3)
    with controls[0]:
        display_mode = st.radio("显示方式", ["仅位移热力图", "CT叠加热力图"], horizontal=True)
    with controls[1]:
        scale_mode = st.selectbox("色阶范围", ["相对增强", "高位移增强", "绝对范围"])
    with controls[2]:
        alpha = st.slider("叠加透明度", 0.0, 1.0, 0.55, 0.05)

    vmin, vmax = ddf_color_limits(mag, scale_mode)
    show_base = display_mode == "CT叠加热力图"
    st.caption(f"当前色阶范围：{format_mm(vmin)} - {format_mm(vmax)} mm")

    columns = st.columns(3)
    planes = [("Axial", "轴状面"), ("Coronal", "冠状面"), ("Sagittal", "矢状面")]
    for col, (plane, cn_name) in zip(columns, planes):
        axis = plane_axis(plane)
        with col:
            index = st.slider(f"{cn_name}DDF", 0, fixed_xyz.shape[axis] - 1, fixed_xyz.shape[axis] // 2, key=f"ddf-{plane}")
            render_heatmap_overlay(
                get_slice(fixed_xyz, plane, index),
                get_slice(mag, plane, index),
                alpha=alpha,
                plane=plane,
                vmin=vmin,
                vmax=vmax,
                show_base=show_base,
                caption=f"{cn_name} 形变强度 #{index}",
            )


METRIC_SPECS = [
    ("NCC", "before_ncc", "after_ncc", "越高越好", True),
    ("MSE", "before_mse", "after_mse", "越低越好", False),
    ("MAE", "before_mae", "after_mae", "越低越好", False),
]


def metric_improvement(before: float, after: float, higher_is_better: bool) -> float:
    return after - before if higher_is_better else before - after


def format_metric(value: float) -> str:
    return f"{float(value):.6f}"


def build_metric_table(metrics: Dict[str, float]) -> List[Dict[str, str]]:
    rows = []
    for label, before_key, after_key, direction, higher_is_better in METRIC_SPECS:
        before = float(metrics[before_key])
        after = float(metrics[after_key])
        improvement = metric_improvement(before, after, higher_is_better)
        improvement_rate = improvement / (abs(before) + 1e-8) * 100.0
        rows.append(
            {
                "指标": label,
                "方向": direction,
                "配准前": format_metric(before),
                "配准后": format_metric(after),
                "改善量": f"{improvement:+.6f}",
                "改善率": f"{improvement_rate:+.4f}%",
            }
        )
    return rows


def render_metric_value_panels(metrics: Dict[str, float]) -> None:
    fig, axes = plt.subplots(1, 3, figsize=(11.5, 3.1), dpi=130)
    for ax, (label, before_key, after_key, direction, higher_is_better) in zip(axes, METRIC_SPECS):
        before = float(metrics[before_key])
        after = float(metrics[after_key])
        improvement = metric_improvement(before, after, higher_is_better)
        values = [before, after]
        x = np.arange(2)

        ax.bar(x, values, width=0.5, color=["#64748b", "#0f766e"])
        ax.plot(x, values, color="#111827", linewidth=1.2, marker="o", markersize=4)
        ax.set_xticks(x, ["配准前", "配准后"])
        ax.set_title(f"{label}（{direction}）")
        ymin = min(0.0, min(values) * 1.18)
        ymax = max(0.0, max(values) * 1.18, 1e-5)
        ax.set_ylim(ymin, ymax)
        ax.grid(axis="y", alpha=0.22)

        for index, value in enumerate(values):
            ax.text(index, value, format_metric(value), ha="center", va="bottom", fontsize=8)
        ax.text(0.5, max(values) * 1.06, f"改善 {improvement:+.6f}", ha="center", fontsize=8, color="#374151")

    fig.tight_layout()
    st.pyplot(fig, width="stretch")
    plt.close(fig)


def render_metric_charts(fixed_xyz: np.ndarray, moving_xyz: np.ndarray, warped_xyz: np.ndarray, ddf_xyz: np.ndarray | None) -> None:
    fixed_xyz, moving_xyz, warped_xyz = crop_to_common_shape(fixed_xyz, moving_xyz, warped_xyz)
    metrics = registration_metrics(fixed_xyz, moving_xyz, warped_xyz)
    metric_rows = build_metric_table(metrics)

    c1, c2, c3 = st.columns(3)
    c1.metric("NCC", format_metric(metrics["after_ncc"]), delta=f"{metrics['ncc_improvement']:+.6f}")
    c2.metric(
        "MSE",
        format_metric(metrics["after_mse"]),
        delta=f"{metrics['after_mse'] - metrics['before_mse']:+.6f}",
        delta_color="inverse",
    )
    c3.metric(
        "MAE",
        format_metric(metrics["after_mae"]),
        delta=f"{metrics['after_mae'] - metrics['before_mae']:+.6f}",
        delta_color="inverse",
    )

    max_improvement_rate = max(abs(float(row["改善率"].rstrip("%"))) for row in metric_rows)
    if max_improvement_rate < 0.1:
        st.info("当前配准前后指标变化低于 0.1%，曲线和柱子高度接近是正常的；这更像是 smoke 权重的验证结果，不是充分训练后的配准效果。")

    st.caption("量化结果由当前加载的 Fixed、Moving、Warped 体数据现场计算；逐切片曲线未平滑、未随机采样。")
    st.table(metric_rows)
    render_metric_value_panels(metrics)

    controls = st.columns(2)
    with controls[0]:
        plane_label = st.selectbox("逐切片平面", ["轴状面", "冠状面", "矢状面"])
    with controls[1]:
        metric_label = st.selectbox("逐切片指标", ["MSE", "MAE", "NCC"])

    axis = {"矢状面": 0, "冠状面": 1, "轴状面": 2}[plane_label]
    metric_key = metric_label.lower()
    higher_is_better = metric_key == "ncc"
    curve = slice_metric_curve(fixed_xyz, moving_xyz, warped_xyz, axis=axis, metric=metric_key)
    slice_index = np.asarray(curve["slice_index"], dtype=np.int32)
    before_curve = np.asarray(curve[f"before_{metric_key}"], dtype=np.float32)
    after_curve = np.asarray(curve[f"after_{metric_key}"], dtype=np.float32)
    improvement_curve = after_curve - before_curve if higher_is_better else before_curve - after_curve

    fig, axes = plt.subplots(
        2,
        1,
        figsize=(10.5, 5.4),
        dpi=130,
        sharex=True,
        gridspec_kw={"height_ratios": [2.0, 1.0]},
    )
    axes[0].plot(slice_index, before_curve, label=f"配准前 {metric_label}", color="#64748b", linewidth=1.5)
    axes[0].plot(slice_index, after_curve, label=f"配准后 {metric_label}", color="#0f766e", linewidth=1.5)
    axes[0].set_title(f"{plane_label}逐切片{metric_label}")
    axes[0].set_ylabel(metric_label)
    axes[0].grid(alpha=0.22)
    axes[0].legend(frameon=False)

    axes[1].axhline(0.0, color="#9ca3af", linewidth=0.9)
    axes[1].plot(slice_index, improvement_curve, color="#b45309", linewidth=1.4)
    axes[1].set_title(f"{metric_label}逐切片改善量")
    axes[1].set_xlabel("切片序号")
    axes[1].set_ylabel("改善量")
    axes[1].grid(alpha=0.22)
    st.pyplot(fig, width="stretch")
    plt.close(fig)

    if ddf_xyz is not None:
        mag = ddf_magnitude(ddf_xyz)
        values = mag[np.isfinite(mag)]
        if values.size == 0:
            return
        fig2, ax = plt.subplots(figsize=(10, 3.2), dpi=130)
        ax.hist(values, bins=80, color="#7c3f00", alpha=0.82)
        for percentile, color in [(50, "#111827"), (95, "#0f766e"), (99, "#dc2626")]:
            marker = float(np.percentile(values, percentile))
            ax.axvline(marker, color=color, linewidth=1.2, label=f"P{percentile}={format_mm(marker)} mm")
        ax.set_title("DDF 位移强度分布")
        ax.set_xlabel("mm")
        ax.set_ylabel("体素数")
        ax.grid(axis="y", alpha=0.2)
        ax.legend(frameon=False)
        st.pyplot(fig2, width="stretch")
        plt.close(fig2)


def load_result_paths(out_dir: str) -> Dict[str, str]:
    out = Path(out_dir)
    return {
        "prepared_moving": str(out / "moving_model_input.nii.gz"),
        "prepared_fixed": str(out / "fixed_model_input.nii.gz"),
        "warped": str(out / "warped_moving.nii.gz"),
        "ddf": str(out / "ddf_mm.nii.gz"),
        "metrics": str(out / "metrics.json"),
    }


def read_json_dict(path: str | Path) -> Dict:
    path = Path(path)
    if not path.exists():
        return {}
    try:
        data = json.loads(path.read_text(encoding="utf-8"))
    except Exception:
        return {}
    return data if isinstance(data, dict) else {}


def same_path(left: str | Path | None, right: str | Path | None) -> bool:
    if not left or not right:
        return False
    try:
        return Path(left).expanduser().resolve(strict=False) == Path(right).expanduser().resolve(strict=False)
    except Exception:
        return str(left) == str(right)


def result_matches_inputs(result: Dict, moving_path: str, fixed_path: str) -> bool:
    return same_path(result.get("moving_path"), moving_path) and same_path(result.get("fixed_path"), fixed_path)


def run_inference_from_ui(moving_path: str, fixed_path: str, checkpoint_path: str, out_dir: str) -> Dict:
    from infer import run_inference

    return run_inference(
        moving_path=moving_path,
        fixed_path=fixed_path,
        checkpoint_path=checkpoint_path,
        out_dir=out_dir,
    )


def prepare_patient1_neck_aligned_inputs() -> Dict:
    from data_loader import convert_dicom_series_to_nifti
    from prealign import prealign_pair

    fixed_raw_path = NIFTI_DIR / "patient1_fixed.nii.gz"
    moving_raw_path = NIFTI_DIR / "patient1_moving.nii.gz"
    convert_dicom_series_to_nifti(
        dicom_dir=DEFAULT_FIXED_DICOM_DIR,
        output_path=fixed_raw_path,
        max_memory_mb=8192,
    )
    convert_dicom_series_to_nifti(
        dicom_dir=DEFAULT_MOVING_DICOM_DIR,
        output_path=moving_raw_path,
        max_memory_mb=8192,
    )
    meta = prealign_pair(
        fixed_input_path=fixed_raw_path,
        moving_input_path=moving_raw_path,
        fixed_output_path=DEFAULT_FIXED_NIFTI,
        moving_output_path=DEFAULT_MOVING_NIFTI,
        max_memory_mb=8192,
    )
    return {
        "moving_translation_mm": list(meta.moving_translation_mm),
        "fixed_neck_center_world_mm": list(meta.fixed_neck_center_world_mm),
        "moving_neck_center_world_mm": list(meta.moving_neck_center_world_mm),
        "target_shape_xyz": list(meta.target_shape_xyz),
    }


def run_training_from_ui(moving_path: str, fixed_path: str, checkpoint_path: str) -> None:
    from model_and_train import train_pair

    train_pair(
        moving_path=moving_path,
        fixed_path=fixed_path,
        checkpoint_path=checkpoint_path,
        epochs=80,
        learning_rate=1e-4,
        smooth_weight=0.01,
        image_loss="mse",
        nb_features=(8, 8, 8, 8, 8),
        save_every=20,
    )


def main() -> None:
    st.markdown(CUSTOM_CSS, unsafe_allow_html=True)
    st.title("VoxelMorph 颈部 CT 配准工作台")

    moving_path = str(DEFAULT_MOVING_NIFTI)
    fixed_path = str(DEFAULT_FIXED_NIFTI)
    checkpoint_path = str(DEFAULT_CHECKPOINT)
    out_dir = str(INFERENCE_DIR)
    display_max_voxels = 30_000_000

    st.caption(
        "患者1专用：固定图像 = 平扫CT；移动图像 = 仰头CT。"
        "先按颈部 foreground 做平移预配准，再进入 VoxelMorph 训练/推理。"
    )
    info_cols = st.columns(4)
    info_cols[0].metric("Fixed", "患者1-平扫CT")
    info_cols[1].metric("Moving", "患者1-仰头CT")
    info_cols[2].metric("模型", Path(checkpoint_path).name)
    info_cols[3].metric("输出", Path(out_dir).name)

    action_cols = st.columns([1, 1, 4])
    with action_cols[0]:
        train_now = st.button("颈部预配准+重新训练", type="primary", width="stretch")
    with action_cols[1]:
        start = st.button("开始推理", width="stretch")

    if train_now:
        with st.spinner("患者1颈部预配准、模型训练和推理中"):
            try:
                load_nifti_cached.clear()
                align_info = prepare_patient1_neck_aligned_inputs()
                run_training_from_ui(moving_path, fixed_path, checkpoint_path)
                result = run_inference_from_ui(moving_path, fixed_path, checkpoint_path, out_dir)
                result["neck_alignment"] = align_info
                load_nifti_cached.clear()
                st.session_state["last_result"] = result
                st.success("颈部预配准、训练和推理完成")
            except Exception as exc:
                st.error(str(exc))

    if start:
        with st.spinner("颈部预配准和推理运行中"):
            try:
                load_nifti_cached.clear()
                align_info = prepare_patient1_neck_aligned_inputs()
                result = run_inference_from_ui(moving_path, fixed_path, checkpoint_path, out_dir)
                result["neck_alignment"] = align_info
                load_nifti_cached.clear()
                st.session_state["last_result"] = result
                st.success("推理完成")
            except Exception as exc:
                st.error(str(exc))

    result_paths = load_result_paths(out_dir)
    last_result = st.session_state.get("last_result", {})
    metrics_path = str(last_result.get("metrics_path", result_paths["metrics"]))
    saved_result = read_json_dict(metrics_path)
    result_info = {**saved_result, **last_result}
    outputs_current = result_matches_inputs(result_info, moving_path, fixed_path)

    prepared_moving_path = str(result_info.get("prepared_moving_path", result_paths["prepared_moving"]))
    prepared_fixed_path = str(result_info.get("prepared_fixed_path", result_paths["prepared_fixed"]))
    if outputs_current:
        warped_path = str(result_info.get("warped_path", result_paths["warped"]))
        ddf_path = str(result_info.get("ddf_path", result_paths["ddf"]))
        display_moving_path = prepared_moving_path if Path(prepared_moving_path).exists() else moving_path
        display_fixed_path = prepared_fixed_path if Path(prepared_fixed_path).exists() else fixed_path
    else:
        warped_path = ""
        ddf_path = ""
        display_moving_path = moving_path
        display_fixed_path = fixed_path

    status_cols = st.columns(4)
    status_cols[0].metric("Moving", "存在" if Path(display_moving_path).exists() else "缺失")
    status_cols[1].metric("Fixed", "存在" if Path(display_fixed_path).exists() else "缺失")
    status_cols[2].metric("Warped", "存在" if Path(warped_path).exists() else "缺失")
    status_cols[3].metric("DDF", "存在" if Path(ddf_path).exists() else "缺失")
    if result_info and not outputs_current:
        st.warning("输出目录中的历史结果与当前输入不匹配，请重新开始推理。")

    alignment_meta = read_json_dict(Path(DEFAULT_FIXED_NIFTI).parent / "patient1_neck_alignment.json")
    translation = alignment_meta.get("moving_translation_mm")
    if isinstance(translation, list) and len(translation) == 3:
        st.caption(
            "颈部预配准平移："
            f"X={float(translation[0]):+.2f} mm，"
            f"Y={float(translation[1]):+.2f} mm，"
            f"Z={float(translation[2]):+.2f} mm"
        )

    try:
        moving_xyz, moving_spacing, moving_stride = load_nifti_cached(display_moving_path, max_voxels=display_max_voxels)
        fixed_xyz, fixed_spacing, fixed_stride = load_nifti_cached(display_fixed_path, max_voxels=display_max_voxels)
    except Exception as exc:
        st.warning(f"待显示数据尚未就绪: {exc}")
        return

    warped_xyz = None
    ddf_xyz = None
    if Path(warped_path).exists():
        try:
            warped_xyz, _, _ = load_nifti_cached(warped_path, max_voxels=display_max_voxels)
        except Exception as exc:
            st.warning(f"Warped 读取失败: {exc}")
    if Path(ddf_path).exists():
        try:
            ddf_xyz, _, _ = load_nifti_cached(ddf_path, max_voxels=display_max_voxels)
        except Exception as exc:
            st.warning(f"DDF 读取失败: {exc}")

    if moving_stride > 1 or fixed_stride > 1:
        st.info(f"网页显示已自动下采样：Moving stride={moving_stride}, Fixed stride={fixed_stride}")

    tab_views, tab_overlay, tab_ddf, tab_metrics = st.tabs(["正交三视图", "重叠对比", "形变场", "量化图"])
    with tab_views:
        render_three_way_views(fixed_xyz, moving_xyz, warped_xyz)

    with tab_overlay:
        if warped_xyz is None:
            st.warning("尚未生成配准后图像。")
        else:
            render_overlay_views(fixed_xyz, warped_xyz)

    with tab_ddf:
        if ddf_xyz is None:
            st.warning("尚未生成 DDF。")
        else:
            render_ddf_views(fixed_xyz, ddf_xyz)

    with tab_metrics:
        if warped_xyz is None:
            st.warning("尚未生成配准后图像。")
        else:
            render_metric_charts(fixed_xyz, moving_xyz, warped_xyz, ddf_xyz)
            metrics_file = Path(metrics_path)
            if metrics_file.exists():
                try:
                    st.json(json.loads(metrics_file.read_text(encoding="utf-8")))
                except Exception:
                    pass


if __name__ == "__main__":
    main()