"""按模板 + 参数生成 Cocos ParticleSystem2D 配置（JSON）。
纯本地、无需 API。运行时把 JSON 喂给 ParticleSystem2D 即可（或转成 .plist）。
"""

import json
import os

# 几套基础粒子模板（可继续加）。坐标/数值为 Cocos ParticleSystem2D 字段。
TEMPLATES = {
    "rain": {
        "emitterType": 0, "duration": -1, "emissionRate": 80, "life": 2.2, "lifeVar": 0.4,
        "angle": 270, "angleVar": 10, "speed": 220, "speedVar": 40,
        "gravityY": -300, "gravityX": 0,
        "startSize": 36, "startSizeVar": 8, "endSize": 36,
        "startSpin": 0, "startSpinVar": 180, "endSpin": 0, "endSpinVar": 180,
        "posVarX": 360, "posVarY": 0,
    },
    "burst": {
        "emitterType": 0, "duration": 0.4, "emissionRate": 600, "life": 0.8, "lifeVar": 0.2,
        "angle": 90, "angleVar": 180, "speed": 320, "speedVar": 80,
        "gravityY": -120, "gravityX": 0,
        "startSize": 28, "startSizeVar": 10, "endSize": 0,
        "posVarX": 8, "posVarY": 8,
    },
    "glow": {
        "emitterType": 0, "duration": -1, "emissionRate": 24, "life": 1.4, "lifeVar": 0.3,
        "angle": 90, "angleVar": 360, "speed": 30, "speedVar": 10,
        "gravityY": 0, "gravityX": 0,
        "startSize": 60, "startSizeVar": 14, "endSize": 0,
        "posVarX": 30, "posVarY": 30,
    },
    "confetti": {
        "emitterType": 0, "duration": 0.6, "emissionRate": 300, "life": 2.0, "lifeVar": 0.5,
        "angle": 90, "angleVar": 60, "speed": 400, "speedVar": 120,
        "gravityY": -260, "gravityX": 0,
        "startSize": 24, "startSizeVar": 8, "endSize": 16,
        "startSpin": 0, "startSpinVar": 360, "endSpin": 0, "endSpinVar": 360,
        "posVarX": 20, "posVarY": 0,
    },
}


def build_particle(vfx_id, template, color, out_dir, texture="particle.png"):
    base = TEMPLATES.get(template)
    if base is None:
        raise ValueError(f"未知粒子模板: {template} (可选 {list(TEMPLATES)})")
    r, g, b = (color + [255, 255, 255])[:3]
    cfg = dict(base)
    cfg.update({
        "id": vfx_id,
        "texture": texture,
        "startColor": [r, g, b, 255],
        "startColorVar": [0, 0, 0, 0],
        "endColor": [r, g, b, 0],
        "endColorVar": [0, 0, 0, 0],
        "totalParticles": max(64, int(base["emissionRate"] * base["life"])),
        "blendFunc": {"src": 770, "dst": 1},  # 加色，适合金币/光效
    })
    os.makedirs(out_dir, exist_ok=True)
    path = os.path.join(out_dir, f"{vfx_id}.particle.json")
    with open(path, "w", encoding="utf-8") as f:
        json.dump(cfg, f, ensure_ascii=False, indent=2)
    return path