import { Injectable } from '@angular/core';
import { VideoGenerationCapability } from '../models/video-generation-capability.model';

@Injectable({ providedIn: 'root' })
export class VideoDurationService {
  private readonly fps = 24;

  secondsToFrames(seconds: number): number {
    const normalized = Math.max(1, Number(seconds) || 5);
    return Math.max(1, Math.round(normalized * this.fps) + 1);
  }

  framesToSeconds(frames: number): number {
    const normalized = Math.max(1, Number(frames) || 121);
    return Math.max(1, Math.round((normalized - 1) / this.fps));
  }

  normalizeSeconds(seconds: number, capability: VideoGenerationCapability): number {
    const raw = Number(seconds);
    const fallback = capability.defaultSeconds || 5;
    const value = Number.isFinite(raw) && raw > 0 ? raw : fallback;
    return Math.max(capability.minSeconds, Math.min(capability.maxSeconds, Math.round(value)));
  }

  normalizeToNearestAllowedSeconds(seconds: number, allowedSeconds: number[] = [5, 10], fallback = 5): number {
    const value = Math.round(Number(seconds) || fallback);
    const candidates = allowedSeconds.filter((item) => Number.isFinite(item) && item > 0);
    if (!candidates.length) return fallback;
    return candidates.reduce((best, current) => {
      const bestDistance = Math.abs(best - value);
      const currentDistance = Math.abs(current - value);
      return currentDistance < bestDistance ? current : best;
    }, candidates[0]);
  }

  validateDuration(seconds: number, capability: VideoGenerationCapability): string {
    if (seconds < capability.minSeconds) return `最短支持 ${capability.minSeconds} 秒`;
    if (seconds > capability.maxSeconds) return `最长支持 ${capability.maxSeconds} 秒`;
    return '';
  }
}