"""VisPy 演示：加载预计算轨迹数据，驱动小球运动动画。

计算与显示完全分离：
  1. 先运行 compute.py  → 生成 output/trajectory.txt（全量 NT 步轨迹）
  2. 再运行 sample.py  → 从 output/trajectory.txt 抽帧生成 output/display.txt
  3. 本文件加载 output/display.txt，按帧播放动画

用法：
    python draw.py                                          # 使用 dynamics 根目录下的 output/
    python draw.py examples/case01/output                   # 指定案例输出目录
"""

import numpy as np
import os
import sys
from vispy import app, scene
from vispy.visuals.transforms import STTransform

sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
import compute

# ===========================================================================
# 加载预计算轨迹
# ===========================================================================
script_dir = os.path.dirname(os.path.abspath(__file__))
if len(sys.argv) > 1:
    # 用户指定了输出目录
    output_dir = os.path.abspath(sys.argv[1])
else:
    output_dir = compute.get_output_dir(script_dir)
os.environ["DYNAMICS_OUTPUT_DIR"] = output_dir
disp_path = os.path.join(output_dir, "display.txt")

if not os.path.exists(disp_path):
    raise FileNotFoundError(
        f"找不到 display.txt！\n"
        f"期望路径: {disp_path}\n"
        f"请先运行 compute.py 计算轨迹，再运行 sample.py 生成显示数组。\n"
        f"用法: python draw.py [案例输出目录]"
    )

disp_data = compute.load_text_data(disp_path)

# 单原子数据（plot_atom：用于信息显示）
DISP_X    = disp_data["disp_x"]
DISP_Y    = disp_data["disp_y"]
DISP_Z    = disp_data["disp_z"]
DISP_VX   = disp_data["disp_vx"]
DISP_VY   = disp_data["disp_vy"]
DISP_VZ   = disp_data["disp_vz"]

# 全原子数据（用于多球绘制）
DISP_ALL_X  = disp_data["disp_all_x"]     # (n_frames, n_atoms)
DISP_ALL_Y  = disp_data["disp_all_y"]
DISP_ALL_Z  = disp_data["disp_all_z"]
DISP_ALL_VX = disp_data["disp_all_vx"]
DISP_ALL_VY = disp_data["disp_all_vy"]
DISP_ALL_VZ = disp_data["disp_all_vz"]

DISP_T    = disp_data["disp_t"]
DISP_STEP = disp_data["disp_step"]
N_FRAMES  = int(disp_data["n_frames"])
NT        = int(disp_data["NT"])
DT        = float(disp_data["DT"])
NSTEP     = int(disp_data["NSTEP"])

# 原子信息
ATOM_IDS  = disp_data.get("atom_ids", np.array([1]))
ATOM_RADII = disp_data.get("atom_radii", np.array([float(disp_data["ball_radius"])]))
N_ATOMS   = len(ATOM_IDS)
PLOT_ATOM_ROW = int(disp_data.get("plot_atom_row", 0))
PLOT_ATOM_ID  = int(disp_data.get("plot_atom_id", ATOM_IDS[0]))
BOND_PAIRS = disp_data.get("bond_pairs", [])

if N_FRAMES <= 0:
    raise ValueError(
        "output/display.txt 中没有可播放的帧，请检查 sample_start/sample_end/NSTEP 配置。")

# 保留模拟边界常量（用于场景缩放、相机等），从 output/display.txt 中读取
X_MIN = float(disp_data["X_MIN"]); X_MAX = float(disp_data["X_MAX"])
Y_MIN = float(disp_data["Y_MIN"]); Y_MAX = float(disp_data["Y_MAX"])
Z_MIN = float(disp_data["Z_MIN"]); Z_MAX = float(disp_data["Z_MAX"])
X0 = float(disp_data["X0"]); Y0 = float(disp_data["Y0"]); Z0 = float(disp_data["Z0"])
raw_alpha = disp_data["alpha"]
if isinstance(raw_alpha, (list, tuple, np.ndarray)):
    alpha_list = [float(a) for a in raw_alpha]
    if len(alpha_list) != 6:
        raise ValueError(f"alpha 数组长度须为 6，实际为 {len(alpha_list)}")
else:
    alpha_list = [float(raw_alpha)] * 6
# 绘图参数
ball_radius = float(disp_data["ball_radius"])
ball_color_r = float(disp_data["ball_color_r"])
ball_color_g = float(disp_data["ball_color_g"])
ball_color_b = float(disp_data["ball_color_b"])
box_color_r = float(disp_data["box_color_r"])
box_color_g = float(disp_data["box_color_g"])
box_color_b = float(disp_data["box_color_b"])


# ===========================================================================
# 图形界面无关的几何参数（不参与物理计算，仅用于场景外观）
# ===========================================================================

info_margin  = 36
axis_length  = 10.0

initial_camera = {
    "distance": 40.0,
    "elevation": 0,
    "azimuth": 0,
    "center": (0, 0, 0),
}


# ===========================================================================
# 创建画布与相机
# ===========================================================================
canvas = scene.SceneCanvas(
    keys="interactive",
    size=(1000, 700),
    bgcolor=(0.08, 0.08, 0.10, 1.0),
    show=True,
)

view = canvas.central_widget.add_view()
view.camera = "turntable"
view.camera.distance  = initial_camera["distance"]
view.camera.elevation = initial_camera["elevation"]
view.camera.azimuth   = initial_camera["azimuth"]
view.camera.center    = initial_camera["center"]


# ===========================================================================
# 场景对象
# ===========================================================================
axis_width = 3
arrow_size = 14
axes_visible = True
axes_group = []

axes_group.append(scene.visuals.Arrow(
    pos=np.array([[0, 0, 0], [axis_length, 0, 0]], dtype=np.float32),
    color=(1.0, 0.2, 0.2, 1.0),
    width=axis_width,
    arrows=np.array([[0, 0, 0, axis_length, 0, 0]], dtype=np.float32),
    arrow_size=arrow_size,
    parent=view.scene,
))
axes_group.append(scene.visuals.Arrow(
    pos=np.array([[0, 0, 0], [0, axis_length, 0]], dtype=np.float32),
    color=(0.2, 1.0, 0.2, 1.0),
    width=axis_width,
    arrows=np.array([[0, 0, 0, 0, axis_length, 0]], dtype=np.float32),
    arrow_size=arrow_size,
    parent=view.scene,
))
axes_group.append(scene.visuals.Arrow(
    pos=np.array([[0, 0, 0], [0, 0, axis_length]], dtype=np.float32),
    color=(0.3, 0.6, 1.0, 1.0),
    width=axis_width,
    arrows=np.array([[0, 0, 0, 0, 0, axis_length]], dtype=np.float32),
    arrow_size=arrow_size,
    parent=view.scene,
))

axes_group.append(scene.visuals.Text(text="x", color=(1.0, 0.2, 0.2, 1.0), font_size=18,
    pos=(axis_length + 0.2, 0, 0), anchor_x="left", anchor_y="center", parent=view.scene))
axes_group.append(scene.visuals.Text(text="y", color=(0.2, 1.0, 0.2, 1.0), font_size=18,
    pos=(0, axis_length + 0.2, 0), anchor_x="left", anchor_y="bottom", parent=view.scene))
axes_group.append(scene.visuals.Text(text="z", color=(0.3, 0.6, 1.0, 1.0), font_size=18,
    pos=(0, 0, axis_length + 0.2), anchor_x="left", anchor_y="bottom", parent=view.scene))

# 所有小球（每个原子一个球，不同颜色）
TAB10_RGB = np.array([
    [0.1216, 0.4667, 0.7059],   # 蓝
    [0.8902, 0.4667, 0.1137],   # 橙
    [0.1725, 0.6275, 0.1725],   # 绿
    [0.8392, 0.1529, 0.1569],   # 红
    [0.5804, 0.4039, 0.7412],   # 紫
    [0.5490, 0.3373, 0.2941],   # 棕
    [0.8902, 0.4667, 0.7608],   # 粉
    [0.4980, 0.4980, 0.4980],   # 灰
    [0.7373, 0.7412, 0.1333],   # 黄绿
    [0.0902, 0.7451, 0.8118],   # 青
])
balls = []
for i in range(N_ATOMS):
    r, g, b = TAB10_RGB[i % len(TAB10_RGB)]
    s = scene.visuals.Sphere(
        radius=float(ATOM_RADII[i]), method="latitude",
        color=(r, g, b, 1.0), edge_color=None, parent=view.scene)
    s.mesh.shading = "smooth"
    balls.append(s)

# 成键线（原子之间的连接）
if len(BOND_PAIRS) > 0:
    n_bonds = len(BOND_PAIRS)
    bond_pos = np.zeros((n_bonds * 2, 3), dtype=np.float32)
    bond_lines = scene.visuals.Line(
        pos=bond_pos, color=(0.7, 0.7, 0.7, 0.8), width=3,
        connect="segments", parent=view.scene)
else:
    bond_lines = None

# 六个面形成立方体边界（每个面独立透明度，alpha<=0 时隐藏该面）
box_size = X_MAX - X_MIN
faces = [
    ((X_MAX, 0, 0), "-x"),
    ((X_MIN, 0, 0), "+x"),
    ((0, Y_MAX, 0), "-y"),
    ((0, Y_MIN, 0), "+y"),
    ((0, 0, Z_MAX), "-z"),
    ((0, 0, Z_MIN), "+z"),
]
for f_idx, (pos, direction) in enumerate(faces):
    a = alpha_list[f_idx]
    if a <= 0:
        continue
    face_color = (box_color_r, box_color_g, box_color_b, a)
    plane = scene.visuals.Plane(
        width=box_size, height=box_size, width_segments=1, height_segments=1,
        direction=direction, color=face_color, parent=view.scene)
    plane.set_gl_state(depth_test=False, blend=True)
    plane.transform = STTransform(translate=pos)

# 右上角：相机信息
camera_info = scene.visuals.Text(
    text="", color="white", font_size=14,
    pos=(0, 0), anchor_x="right", anchor_y="top", parent=canvas.scene)

# 左上角：小球信息
ball_info = scene.visuals.Text(
    text="", color=(0.2, 1.0, 0.2, 1.0), font_size=28,
    pos=(0, 0), anchor_x="left", anchor_y="top",
    face="黑体", bold=True, parent=canvas.scene)

# 左上角：reset 按钮（在 info 上方）
reset_btn_size = (60, 30)
reset_button = scene.visuals.Rectangle(
    center=(reset_btn_size[0] / 2 + 8, reset_btn_size[1] / 2 + 8),
    width=reset_btn_size[0], height=reset_btn_size[1],
    radius=6, color=(0.18, 0.35, 0.65, 0.85),
    border_color="white", parent=canvas.scene)
reset_button_label = scene.visuals.Text(
    text="reset", color="white", font_size=16,
    pos=(reset_btn_size[0] / 2 + 8, reset_btn_size[1] / 2 + 8),
    anchor_x="center", anchor_y="center",
    bold=True, parent=canvas.scene)

# 信息显示/隐藏 切换按钮（左上角小方块，在 reset 下方）
info_btn_size = (60, 30)
info_toggle_visible = True
info_button = scene.visuals.Rectangle(
    center=(info_btn_size[0] / 2 + 8, info_btn_size[1] / 2 + 8),
    width=info_btn_size[0], height=info_btn_size[1],
    radius=6, color=(0.9, 0.3, 0.3, 0.9),
    border_color="white", parent=canvas.scene)
info_button_label = scene.visuals.Text(
    text="info", color="white", font_size=16,
    pos=(info_btn_size[0] / 2 + 8, info_btn_size[1] / 2 + 8),
    anchor_x="center", anchor_y="center",
    bold=True, parent=canvas.scene)

# 强制在初始化时定位到左上角（canvas.scene坐标系：左下角为原点）
_cw, _ch = canvas.size
reset_button.center = (reset_btn_size[0] / 2 + 8, _ch - reset_btn_size[1] / 2 - 8 - info_btn_size[1] - 4)
reset_button_label.pos = reset_button.center
info_button.center = (info_btn_size[0] / 2 + 8, _ch - info_btn_size[1] / 2 - 8)
info_button_label.pos = info_button.center

# axes 显示/隐藏 按钮（在 info 下方）
axes_btn_size = (60, 30)
axes_button = scene.visuals.Rectangle(
    center=(axes_btn_size[0] / 2 + 8, axes_btn_size[1] / 2 + 8),
    width=axes_btn_size[0], height=axes_btn_size[1],
    radius=6, color=(0.3, 0.7, 0.3, 0.9),
    border_color="white", parent=canvas.scene)
axes_button_label = scene.visuals.Text(
    text="axes", color="white", font_size=16,
    pos=(axes_btn_size[0] / 2 + 8, axes_btn_size[1] / 2 + 8),
    anchor_x="center", anchor_y="center",
    bold=True, parent=canvas.scene)
axes_button.center = (axes_btn_size[0] / 2 + 8, _ch - axes_btn_size[1] / 2 - 8 - info_btn_size[1] - 4 - axes_btn_size[1] - 4)
axes_button_label.pos = axes_button.center


# ===========================================================================
# 回调函数
# ===========================================================================

def update_camera_info(event=None):
    c = view.camera
    camera_info.text = (
        "Camera\n"
        f"center = ({c.center[0]:.2f}, {c.center[1]:.2f}, {c.center[2]:.2f})\n"
        f"distance = {c.distance:.2f}\n"
        f"elevation = {c.elevation:.2f}\n"
        f"azimuth = {c.azimuth:.2f}"
    )


def update_ball_info(frame_idx, x, y, z, vx, vy, vz):
    step = int(DISP_STEP[frame_idx])
    t    = float(DISP_T[frame_idx])
    ball_info.text = (
        f"原子 {PLOT_ATOM_ID}  (共 {N_ATOMS} 个原子)\n"
        f"frame {frame_idx+1}/{N_FRAMES}  |  saved step {step}/{NT-1}\n"
        f"t = {t:.2f} s  |  dt = {DT:.3f} s  |  nstep = {NSTEP}\n"
        f"Position: ({x:.2f}, {y:.2f}, {z:.2f})\n"
        f"Velocity: ({vx:.2f}, {vy:.2f}, {vz:.2f})\n"
    )


def reposition_camera_info(event=None):
    width, height = canvas.size
    camera_info.pos  = (width - 20, height - 20)
    # reset → info → axes 三按钮纵向排列
    gap = 4
    info_y = info_btn_size[1] / 2 + 8
    reset_y = info_y + info_btn_size[1] + gap
    axes_y = info_y + info_btn_size[1] + gap + axes_btn_size[1] + gap
    reset_button.center = (reset_btn_size[0] / 2 + 8, height - reset_y)
    reset_button_label.pos = reset_button.center
    info_button.center = (info_btn_size[0] / 2 + 8, height - info_y)
    info_button_label.pos = info_button.center
    axes_button.center = (axes_btn_size[0] / 2 + 8, height - axes_y)
    axes_button_label.pos = axes_button.center
    # info 文字放在所有按钮下方
    buttons_bottom = height - (axes_y + axes_btn_size[1] / 2)
    ball_info.pos = (info_margin, buttons_bottom - 10)
    update_ball_info(frame_idx, DISP_X[frame_idx], DISP_Y[frame_idx], DISP_Z[frame_idx],
                     DISP_VX[frame_idx], DISP_VY[frame_idx], DISP_VZ[frame_idx])
    update_camera_info()


def handle_view_interaction(event):
    update_camera_info()


def rotate_about_screen_normal(angle):
    if hasattr(view.camera, "roll"):
        view.camera.roll = (view.camera.roll + angle) % 360
    else:
        view.camera.azimuth = (view.camera.azimuth + angle) % 360
    update_camera_info()


def handle_key_press(event):
    key_name = ""
    if getattr(event, "text", None):
        key_name = event.text.lower()
    elif getattr(event, "key", None) is not None:
        key_name = str(event.key).lower()
    if key_name == "q":
        rotate_about_screen_normal(-90)
    elif key_name == "e":
        rotate_about_screen_normal(90)


def reset_camera_view():
    global frame_idx
    frame_idx = 0
    # 立即复位所有小球到第 0 帧
    for i in range(N_ATOMS):
        balls[i].transform = STTransform(translate=(
            float(DISP_ALL_X[frame_idx, i]),
            float(DISP_ALL_Y[frame_idx, i]),
            float(DISP_ALL_Z[frame_idx, i]),
        ))
    if bond_lines is not None and len(BOND_PAIRS) > 0:
        pos = np.zeros((len(BOND_PAIRS) * 2, 3), dtype=np.float32)
        for b_idx, (i, j) in enumerate(BOND_PAIRS):
            pos[b_idx * 2]     = [DISP_ALL_X[frame_idx, i], DISP_ALL_Y[frame_idx, i], DISP_ALL_Z[frame_idx, i]]
            pos[b_idx * 2 + 1] = [DISP_ALL_X[frame_idx, j], DISP_ALL_Y[frame_idx, j], DISP_ALL_Z[frame_idx, j]]
        bond_lines.set_data(pos=pos)
    # 复位相机
    view.camera.distance  = initial_camera["distance"]
    view.camera.elevation  = initial_camera["elevation"]
    view.camera.azimuth    = initial_camera["azimuth"]
    view.camera.center     = initial_camera["center"]
    if hasattr(view.camera, "roll"):
        view.camera.roll = 0
    update_camera_info()


def handle_mouse_press(event):
    global info_toggle_visible, axes_visible
    if event.pos is None:
        return
    ex, ey = event.pos

    # reset 按钮
    bx, by = reset_button.center
    lw = reset_btn_size[0] / 2;  lh = reset_btn_size[1] / 2
    if (bx - lw) <= ex <= (bx + lw) and (by - lh) <= ey <= (by + lh):
        reset_camera_view()
        return

    # info 按钮
    bx, by = info_button.center
    if (bx - info_btn_size[0]/2) <= ex <= (bx + info_btn_size[0]/2) and (by - info_btn_size[1]/2) <= ey <= (by + info_btn_size[1]/2):
        info_toggle_visible = not info_toggle_visible
        ball_info.visible = info_toggle_visible
        camera_info.visible = info_toggle_visible
        return

    # axes 按钮
    bx, by = axes_button.center
    if (bx - axes_btn_size[0]/2) <= ex <= (bx + axes_btn_size[0]/2) and (by - axes_btn_size[1]/2) <= ey <= (by + axes_btn_size[1]/2):
        axes_visible = not axes_visible
        for axis in axes_group:
            axis.visible = axes_visible


# ===========================================================================
# 动画初始化
# ===========================================================================
frame_idx = 0

# 初始帧：摆放所有小球并刷新 UI
for i in range(N_ATOMS):
    balls[i].transform = STTransform(translate=(
        float(DISP_ALL_X[frame_idx, i]),
        float(DISP_ALL_Y[frame_idx, i]),
        float(DISP_ALL_Z[frame_idx, i]),
    ))
# 初始帧：更新成键线
if bond_lines is not None and len(BOND_PAIRS) > 0:
    pos = np.zeros((len(BOND_PAIRS) * 2, 3), dtype=np.float32)
    for b_idx, (i, j) in enumerate(BOND_PAIRS):
        pos[b_idx * 2]     = [DISP_ALL_X[frame_idx, i], DISP_ALL_Y[frame_idx, i], DISP_ALL_Z[frame_idx, i]]
        pos[b_idx * 2 + 1] = [DISP_ALL_X[frame_idx, j], DISP_ALL_Y[frame_idx, j], DISP_ALL_Z[frame_idx, j]]
    bond_lines.set_data(pos=pos)
reposition_camera_info()
update_ball_info(frame_idx,
    float(DISP_X[frame_idx]), float(DISP_Y[frame_idx]), float(DISP_Z[frame_idx]),
    float(DISP_VX[frame_idx]), float(DISP_VY[frame_idx]), float(DISP_VZ[frame_idx]))

print(f"[draw] 加载 output/display.txt: {N_FRAMES} 帧, {N_ATOMS} 个原子, NT={NT}, DT={DT}, NSTEP={NSTEP}")
print(f"[draw] 绘图参数: ball_radius={ball_radius}, box_color=({box_color_r:.2f},{box_color_g:.2f},{box_color_b:.2f}), alpha={alpha_list}")


# ===========================================================================
# 每帧回调：仅推进帧索引，从预存数组读取位置，零物理计算
# ===========================================================================
def update(event):
    global frame_idx
    frame_idx = (frame_idx + 1) % N_FRAMES     # 循环播放

    # 更新所有小球位置
    for i in range(N_ATOMS):
        x = float(DISP_ALL_X[frame_idx, i])
        y = float(DISP_ALL_Y[frame_idx, i])
        z = float(DISP_ALL_Z[frame_idx, i])
        balls[i].transform = STTransform(translate=(x, y, z))

    # 更新成键线
    if bond_lines is not None and len(BOND_PAIRS) > 0:
        pos = np.zeros((len(BOND_PAIRS) * 2, 3), dtype=np.float32)
        for b_idx, (i, j) in enumerate(BOND_PAIRS):
            pos[b_idx * 2]     = [DISP_ALL_X[frame_idx, i], DISP_ALL_Y[frame_idx, i], DISP_ALL_Z[frame_idx, i]]
            pos[b_idx * 2 + 1] = [DISP_ALL_X[frame_idx, j], DISP_ALL_Y[frame_idx, j], DISP_ALL_Z[frame_idx, j]]
        bond_lines.set_data(pos=pos)

    # 信息面板显示 plot_atom 的数据
    x = float(DISP_X[frame_idx])
    y = float(DISP_Y[frame_idx])
    z = float(DISP_Z[frame_idx])
    vx = float(DISP_VX[frame_idx])
    vy = float(DISP_VY[frame_idx])
    vz = float(DISP_VZ[frame_idx])
    update_ball_info(frame_idx, x, y, z, vx, vy, vz)
    update_camera_info()


# ===========================================================================
# 事件绑定与启动
# ===========================================================================
timer = app.Timer(interval=0.02, connect=update, start=True)
canvas.events.mouse_move.connect(handle_view_interaction)
canvas.events.mouse_press.connect(handle_mouse_press)
canvas.events.mouse_wheel.connect(handle_view_interaction)
canvas.events.resize.connect(reposition_camera_info)
canvas.events.key_press.connect(handle_key_press)

if hasattr(canvas, "native") and hasattr(canvas.native, "setFocus"):
    canvas.native.setFocus()


if __name__ == "__main__":
    app.run()