/**
 * 生成用于测试与验收的 BVH 样例（60 帧挥手 + 深蹲）。
 * 用法：node test/fixtures/generate-sample-bvh.mjs [输出路径]
 */
import { writeFileSync } from 'node:fs';
import { dirname, join } from 'node:path';
import { fileURLToPath } from 'node:url';

const here = dirname(fileURLToPath(import.meta.url));
const outPath = process.argv[2] ?? join(here, 'sample.bvh');

const HIERARCHY = `HIERARCHY
ROOT Hips
{
  OFFSET 0.0 0.0 0.0
  CHANNELS 6 Xposition Yposition Zposition Zrotation Xrotation Yrotation
  JOINT Spine
  {
    OFFSET 0.0 12.0 0.0
    CHANNELS 3 Zrotation Xrotation Yrotation
    JOINT Neck
    {
      OFFSET 0.0 14.0 0.0
      CHANNELS 3 Zrotation Xrotation Yrotation
      JOINT Head
      {
        OFFSET 0.0 8.0 0.0
        CHANNELS 3 Zrotation Xrotation Yrotation
        End Site
        {
          OFFSET 0.0 8.0 0.0
        }
      }
    }
    JOINT LeftShoulder
    {
      OFFSET 6.0 10.0 0.0
      CHANNELS 3 Zrotation Xrotation Yrotation
      JOINT LeftArm
      {
        OFFSET 12.0 0.0 0.0
        CHANNELS 3 Zrotation Xrotation Yrotation
        JOINT LeftForeArm
        {
          OFFSET 22.0 0.0 0.0
          CHANNELS 3 Zrotation Xrotation Yrotation
          JOINT LeftHand
          {
            OFFSET 20.0 0.0 0.0
            CHANNELS 3 Zrotation Xrotation Yrotation
            End Site
            {
              OFFSET 8.0 0.0 0.0
            }
          }
        }
      }
    }
    JOINT RightShoulder
    {
      OFFSET -6.0 10.0 0.0
      CHANNELS 3 Zrotation Xrotation Yrotation
      JOINT RightArm
      {
        OFFSET -12.0 0.0 0.0
        CHANNELS 3 Zrotation Xrotation Yrotation
        JOINT RightForeArm
        {
          OFFSET -22.0 0.0 0.0
          CHANNELS 3 Zrotation Xrotation Yrotation
          JOINT RightHand
          {
            OFFSET -20.0 0.0 0.0
            CHANNELS 3 Zrotation Xrotation Yrotation
            End Site
            {
              OFFSET -8.0 0.0 0.0
            }
          }
        }
      }
    }
  }
  JOINT LeftUpLeg
  {
    OFFSET 5.0 -3.0 0.0
    CHANNELS 3 Zrotation Xrotation Yrotation
    JOINT LeftLeg
    {
      OFFSET 0.0 -26.0 0.0
      CHANNELS 3 Zrotation Xrotation Yrotation
      JOINT LeftFoot
      {
        OFFSET 0.0 -25.0 0.0
        CHANNELS 3 Zrotation Xrotation Yrotation
        JOINT LeftToeBase
        {
          OFFSET 0.0 -4.0 10.0
          CHANNELS 3 Zrotation Xrotation Yrotation
          End Site
          {
            OFFSET 0.0 -2.0 6.0
          }
        }
      }
    }
  }
  JOINT RightUpLeg
  {
    OFFSET -5.0 -3.0 0.0
    CHANNELS 3 Zrotation Xrotation Yrotation
    JOINT RightLeg
    {
      OFFSET 0.0 -26.0 0.0
      CHANNELS 3 Zrotation Xrotation Yrotation
      JOINT RightFoot
      {
        OFFSET 0.0 -25.0 0.0
        CHANNELS 3 Zrotation Xrotation Yrotation
        JOINT RightToeBase
        {
          OFFSET 0.0 -4.0 10.0
          CHANNELS 3 Zrotation Xrotation Yrotation
          End Site
          {
            OFFSET 0.0 -2.0 6.0
          }
        }
      }
    }
  }
}
MOTION
`;

/** 通道顺序（与上面的 HIERARCHY 一致）：Hips 6 通道 + 19 个关节各 3 通道 */
const JOINT_ORDER = [
  'Hips',
  'Spine',
  'Neck',
  'Head',
  'LeftShoulder',
  'LeftArm',
  'LeftForeArm',
  'LeftHand',
  'RightShoulder',
  'RightArm',
  'RightForeArm',
  'RightHand',
  'LeftUpLeg',
  'LeftLeg',
  'LeftFoot',
  'LeftToeBase',
  'RightUpLeg',
  'RightLeg',
  'RightFoot',
  'RightToeBase',
];
const CHANNELS = 6 + 3 * (JOINT_ORDER.length - 1);
const FRAMES = 60;
const FRAME_TIME = 1 / 30;

const lines = [];
for (let f = 0; f < FRAMES; f += 1) {
  const t = f / FRAMES;
  const phase = Math.sin(t * Math.PI * 2);
  const squat = (1 - Math.cos(t * Math.PI * 2)) / 2;

  const values = [];
  for (const joint of JOINT_ORDER) {
    if (joint === 'Hips') {
      values.push(0, -squat * 12, 0); // Xposition Yposition Zposition
      values.push(phase * 6, 0, 0); // Zrotation Xrotation Yrotation
      continue;
    }
    const rot = { z: 0, x: 0, y: 0 };
    if (joint === 'LeftArm') rot.z = 20 + phase * 55;
    if (joint === 'RightArm') rot.z = -20 - phase * 55;
    if (joint === 'LeftForeArm') rot.x = -25 - phase * 30;
    if (joint === 'RightForeArm') rot.x = -25 + phase * 30;
    if (joint === 'LeftUpLeg') rot.x = -squat * 35;
    if (joint === 'RightUpLeg') rot.x = -squat * 35;
    if (joint === 'LeftLeg') rot.x = squat * 60;
    if (joint === 'RightLeg') rot.x = squat * 60;
    if (joint === 'LeftFoot') rot.x = -squat * 25;
    if (joint === 'RightFoot') rot.x = -squat * 25;
    if (joint === 'Spine') rot.z = phase * 5;
    if (joint === 'Neck') rot.z = -phase * 3;
    values.push(rot.z, rot.x, rot.y);
  }
  if (values.length !== CHANNELS) throw new Error(`帧 ${f} 通道数错误：${values.length}`);
  lines.push(values.map((v) => v.toFixed(4)).join(' '));
}

const text = `${HIERARCHY}Frames: ${FRAMES}\nFrame Time: ${FRAME_TIME.toFixed(7)}\n${lines.join('\n')}\n`;
writeFileSync(outPath, text, 'utf8');
console.log(`已生成 ${outPath}（${FRAMES} 帧，${CHANNELS} 通道，${text.length} 字节）`);