import { Vec3 } from 'cc';
import { BulletCountConfig, SpawnInfo } from '../BulletTypes';

/**
 * BulletCount - 计算子弹生成信息（位置、方向、延迟）
 * 仅负责基于数量与扩散/连发逻辑生成 spawn 列表，不包含技能加成。
 */
export class BulletCount {
  /**
   * 计算发射队列
   */
  static calculateSpawns(countCfg: BulletCountConfig, firePos: Vec3, direction: Vec3): SpawnInfo[] {
    const dir = direction?.clone() ?? new Vec3(1, 0, 0);
    if (dir.length() === 0) dir.set(1, 0, 0);
    dir.normalize();

    const result: SpawnInfo[] = [];
    const type = countCfg?.type ?? 'single';
    const amount = Math.max(1, countCfg?.amount ?? 1);
    const spreadAngle = countCfg?.spreadAngle ?? 0;
    const burstCount = Math.max(1, countCfg?.burstCount ?? 1);
    const burstDelay = Math.max(0, countCfg?.burstDelay ?? 0); // 秒

    if (type === 'single') {
      for (let i = 0; i < amount; i++) {
        result.push({ position: firePos.clone(), direction: dir.clone(), delayMs: 0 });
      }
      return result;
    }

    if (type === 'spread') {
      // 在 [-spread/2, +spread/2] 范围内平均分布
      const count = amount;
      const step = count > 1 ? spreadAngle / (count - 1) : 0;
      const start = -spreadAngle / 2;
      for (let i = 0; i < count; i++) {
        const deg = start + step * i;
        const rad = (deg * Math.PI) / 180;
        const d = rotateVec(dir, rad);
        result.push({ position: firePos.clone(), direction: d, delayMs: 0 });
      }
      return result;
    }

    if (type === 'burst') {
      // 连发：每次 burst 发 amount 发子弹，总计 burstCount 次；每次之间间隔 burstDelay
      const ms = Math.floor(burstDelay * 1000);
      for (let b = 0; b < burstCount; b++) {
        const delayMs = ms * b;
        for (let i = 0; i < amount; i++) {
          result.push({ position: firePos.clone(), direction: dir.clone(), delayMs });
        }
      }
      return result;
    }

    // 默认回退到单发
    result.push({ position: firePos.clone(), direction: dir.clone(), delayMs: 0 });
    return result;
  }
}

function rotateVec(v: Vec3, rad: number): Vec3 {
  const c = Math.cos(rad);
  const s = Math.sin(rad);
  return new Vec3(v.x * c - v.y * s, v.x * s + v.y * c, v.z);
}