from typing import List
from .base import EffectProcessor

class SpeedEffect(EffectProcessor):
    """视频变速效果处理器"""
    
    def validate_params(self) -> bool:
        """验证参数：速度倍数"""
        if not self.params:
            return True  # 默认不变速
            
        try:
            speed = float(self.params)
            return speed > 0
        except ValueError:
            return False
            
    def generate_filter_args(self, video_input: str, effect_index: int) -> tuple[List[str], str]:
        """生成变速效果的滤镜参数"""
        if not self.validate_params():
            return [], video_input
            
        if not self.params or self.params == "1":
            return [], video_input  # 不需要变速
            
        speed = float(self.params)
        output_stream = f"[v_eff{effect_index}]"
        
        # 使用setpts进行变速
        filter_args = [f"{video_input}setpts={speed}*PTS{output_stream}"]
        
        return filter_args, output_stream
        
    def get_effect_name(self) -> str:
        return "ospeed"