"""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_NIFTI,
    DEFAULT_MOVING_NIFTI,
    INFERENCE_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="expanded",
)


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) -> np.ndarray:
    """统一显示方向，让三视图在网页中更接近医学浏览器观感。"""

    return np.rot90(image)


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 alpha_overlay(fixed_slice: np.ndarray, warped_slice: np.ndarray, alpha: float = 0.45) -> np.ndarray:
    fixed_norm = normalize_slice(fixed_slice)
    warped_norm = normalize_slice(warped_slice)
    rgb = np.zeros((*fixed_norm.shape, 3), dtype=np.float32)
    rgb[..., 0] = warped_norm
    rgb[..., 1] = fixed_norm * (1.0 - alpha) + warped_norm * alpha
    rgb[..., 2] = fixed_norm
    return np.clip(rgb, 0.0, 1.0)


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


def render_heatmap_overlay(base_slice: np.ndarray, mag_slice: np.ndarray, alpha: float, caption: str) -> None:
    fig, ax = plt.subplots(figsize=(4.8, 4.8), dpi=120)
    ax.imshow(orient_for_display(normalize_slice(base_slice)), cmap="gray", interpolation="nearest")
    heat = orient_for_display(mag_slice)
    im = ax.imshow(heat, cmap="inferno", alpha=alpha, 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_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}")


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", ["Alpha 融合", "棋盘格"], horizontal=True)
    alpha = st.slider("透明度", 0.0, 1.0, 0.45, 0.05)
    tile = st.slider("棋盘格尺寸", 8, 64, 24, 4)

    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}")
            else:
                render_rgb(alpha_overlay(fixed_slice, warped_slice, alpha=alpha), f"{cn_name} 融合 #{index}")


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)
    alpha = st.slider("热力图透明度", 0.0, 1.0, 0.55, 0.05)

    stats = ddf_summary(ddf_xyz)
    c1, c2, c3, c4 = st.columns(4)
    c1.metric("平均位移 mm", f"{stats['ddf_mean']:.3f}")
    c2.metric("P95 mm", f"{stats['ddf_p95']:.3f}")
    c3.metric("最大 mm", f"{stats['ddf_max']:.3f}")
    c4.metric("标准差", f"{stats['ddf_std']:.3f}")

    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,
                caption=f"{cn_name} 形变强度 #{index}",
            )


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)

    c1, c2, c3 = st.columns(3)
    c1.metric("NCC", f"{metrics['after_ncc']:.4f}", delta=f"{metrics['ncc_improvement']:+.4f}")
    c2.metric(
        "MSE",
        f"{metrics['after_mse']:.5f}",
        delta=f"{metrics['after_mse'] - metrics['before_mse']:+.5f}",
        delta_color="inverse",
    )
    c3.metric(
        "MAE",
        f"{metrics['after_mae']:.5f}",
        delta=f"{metrics['after_mae'] - metrics['before_mae']:+.5f}",
        delta_color="inverse",
    )

    labels = ["NCC", "MSE", "MAE"]
    before = [metrics["before_ncc"], metrics["before_mse"], metrics["before_mae"]]
    after = [metrics["after_ncc"], metrics["after_mse"], metrics["after_mae"]]

    fig, axes = plt.subplots(1, 2, figsize=(10, 3.6), dpi=130)
    x = np.arange(len(labels))
    width = 0.36
    axes[0].bar(x - width / 2, before, width, label="配准前", color="#64748b")
    axes[0].bar(x + width / 2, after, width, label="配准后", color="#0f766e")
    axes[0].set_xticks(x, labels)
    axes[0].set_title("配准前后指标对比")
    axes[0].legend(frameon=False)
    axes[0].grid(axis="y", alpha=0.22)

    curve = slice_metric_curve(fixed_xyz, moving_xyz, warped_xyz, axis=2)
    axes[1].plot(curve["slice_index"], curve["before_mse"], label="配准前 MSE", color="#64748b", linewidth=1.8)
    axes[1].plot(curve["slice_index"], curve["after_mse"], label="配准后 MSE", color="#b45309", linewidth=1.8)
    axes[1].set_title("轴状面逐切片误差")
    axes[1].set_xlabel("Slice")
    axes[1].grid(alpha=0.22)
    axes[1].legend(frameon=False)
    st.pyplot(fig, width="stretch")
    plt.close(fig)

    if ddf_xyz is not None:
        mag = ddf_magnitude(ddf_xyz)
        fig2, ax = plt.subplots(figsize=(10, 3.2), dpi=130)
        ax.hist(mag.ravel(), bins=80, color="#7c3f00", alpha=0.82)
        ax.set_title("DDF 位移强度分布")
        ax.set_xlabel("mm")
        ax.set_ylabel("Voxel count")
        ax.grid(axis="y", alpha=0.2)
        st.pyplot(fig2, width="stretch")
        plt.close(fig2)


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


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

    candidates = discover_nifti_files()
    checkpoint_candidates = discover_checkpoint_files()
    with st.sidebar:
        st.header("输入")
        moving_path = choose_path("Moving", DEFAULT_MOVING_NIFTI, candidates)
        fixed_path = choose_path("Fixed", DEFAULT_FIXED_NIFTI, candidates)
        checkpoint_path = choose_path("模型权重", DEFAULT_CHECKPOINT, checkpoint_candidates)
        out_dir = st.text_input("输出目录", value=str(INFERENCE_DIR))
        display_max_voxels = st.slider("Web显示体素上限", 2_000_000, 30_000_000, 14_000_000, 1_000_000)

        start = st.button("开始推理", type="primary", width="stretch")
        if start:
            with st.spinner("推理运行中"):
                try:
                    load_nifti_cached.clear()
                    result = run_inference_from_ui(moving_path, fixed_path, checkpoint_path, out_dir)
                    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", {})
    warped_path = str(last_result.get("warped_path", result_paths["warped"]))
    ddf_path = str(last_result.get("ddf_path", result_paths["ddf"]))
    metrics_path = str(last_result.get("metrics_path", result_paths["metrics"]))

    status_cols = st.columns(4)
    status_cols[0].metric("Moving", "存在" if Path(moving_path).exists() else "缺失")
    status_cols[1].metric("Fixed", "存在" if Path(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")

    try:
        moving_xyz, moving_spacing, moving_stride = load_nifti_cached(moving_path, max_voxels=display_max_voxels)
        fixed_xyz, fixed_spacing, fixed_stride = load_nifti_cached(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:
        view_target = st.radio("显示对象", ["固定图像", "移动图像", "配准后图像"], horizontal=True)
        if view_target == "固定图像":
            render_three_views(fixed_xyz, "固定图像")
        elif view_target == "移动图像":
            render_three_views(moving_xyz, "移动图像")
        elif warped_xyz is not None:
            render_three_views(warped_xyz, "配准后图像")
        else:
            st.warning("尚未生成配准后图像。")

    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()