import cv2
import numpy as np
import random
import math

def generate_table_video(output_path='rotating_table.mp4'):
    # 参数设置
    width, height = 800, 800
    fps = 30
    duration_ring = 2  # 红圈停留2秒
    duration_rotate = 5  # 旋转5秒
    total_frames = (duration_ring + duration_rotate) * fps
    
    # 桌子属性
    table_size = 400
    table_color = (99, 110, 141)  # BGR 格式的 #8d6e63
    ring_color = (59, 59, 255)    # 红色
    text_color = (255, 255, 255)  # 白色
    
    # 随机选择一个角落 (0:左上, 1:右上, 2:右下, 3:左下)
    chosen_corner = random.randint(0, 3)
    corners_rel = [
        (-140, -140), (140, -140), (140, 140), (-140, 140)
    ]
    target_pos = corners_rel[chosen_corner]
    
    # 视频写入器
    fourcc = cv2.VideoWriter_fourcc(*'mp4v')
    out = cv2.VideoWriter(output_path, fourcc, fps, (width, height))

    for frame_idx in range(total_frames):
        # 创建画布 (浅灰色背景)
        img = np.full((height, width, 3), (245, 242, 240), dtype=np.uint8)
        
        current_time = frame_idx / fps
        angle = 0
        show_letters = False
        
        # 逻辑判断
        if current_time < duration_ring:
            # 第一阶段：红圈停留
            angle = 0
            # 模拟闪烁效果
            ring_opacity = 1.0 if (int(current_time * 4) % 2 == 0) else 0.7
        else:
            # 第二阶段：旋转
            rotate_time = current_time - duration_ring
            # 使用简单的缓动函数 (Ease-in-out) 模拟平滑旋转至 380 度
            # t 从 0 到 1
            t = rotate_time / duration_rotate
            # 缓动函数: 3t^2 - 2t^3
            ease_t = 3 * (t**2) - 2 * (t**3)
            angle = ease_t * 380
            
            if frame_idx == total_frames - 1:
                show_letters = True

        # 1. 绘制桌子 (旋转矩形)
        center = (width // 2, height // 2)
        # 计算旋转矩阵
        M = cv2.getRotationMatrix2D(center, -angle, 1.0) # OpenCV 逆时针为正，所以取负
        
        # 创建桌子图层
        table_layer = np.zeros_like(img)
        rect_pts = np.array([
            [center[0] - table_size//2, center[1] - table_size//2],
            [center[0] + table_size//2, center[1] - table_size//2],
            [center[0] + table_size//2, center[1] + table_size//2],
            [center[0] - table_size//2, center[1] + table_size//2]
        ])
        
        # 旋转桌子顶点
        ones = np.ones(shape=(len(rect_pts), 1))
        pts_ones = np.hstack([rect_pts, ones])
        transformed_pts = pts_ones.dot(M.T).astype(np.int32)
        
        # 绘制圆角矩形桌子 (简化为填充多边形)
        cv2.fillPoly(table_layer, [transformed_pts], table_color)
        
        # 叠加桌子
        mask = np.any(table_layer != 0, axis=-1)
        img[mask] = table_layer[mask]

        # 2. 绘制红圈 (仅在第一阶段)
        if current_time < duration_ring:
            # 圈的位置相对于中心是不旋转的
            ring_x = center[0] + target_pos[0]
            ring_y = center[1] + target_pos[1]
            cv2.circle(img, (ring_x, ring_y), 40, ring_color, 5)

        # 3. 绘制字母 (仅在最后一帧)
        if show_letters:
            letters = ["A", "B", "C", "D"]
            # 计算 380 度后的旋转矩阵
            final_M = cv2.getRotationMatrix2D(center, -380, 1.0)
            
            for i, char in enumerate(letters):
                orig_pos = np.array([center[0] + corners_rel[i][0], center[1] + corners_rel[i][1], 1])
                new_pos = final_M.dot(orig_pos)
                cv2.putText(img, char, (int(new_pos[0]-20), int(new_pos[1]+20)), 
                            cv2.FONT_HERSHEY_SIMPLEX, 2, text_color, 5, cv2.LINE_AA)

        out.write(img)

    out.release()
    print(f"视频已生成: {output_path}")

if __name__ == "__main__":
    generate_table_video()