import { AlignedSegment, combineVideoWithSubtitles } from '../services/transcriptionApi';

// Generate SRT subtitle format
export const generateSRT = (segments: AlignedSegment[]): string => {
  let srt = "";
  segments.forEach((segment, index) => {
    const startTime = formatTimeForSRT(segment.start);
    const endTime = formatTimeForSRT(segment.end);
    srt += `${index + 1}\n`;
    srt += `${startTime} --> ${endTime}\n`;
    srt += `${segment.text}\n\n`;
  });
  return srt;
};

// Generate WebVTT subtitle format
export const generateWebVTT = (segments: AlignedSegment[]): string => {
  let vtt = "WEBVTT\n\n";
  segments.forEach((segment, index) => {
    const startTime = formatTimeForVTT(segment.start);
    const endTime = formatTimeForVTT(segment.end);
    vtt += `${index + 1}\n`;
    vtt += `${startTime} --> ${endTime}\n`;
    vtt += `${segment.text}\n\n`;
  });
  return vtt;
};

// Format time for SRT (HH:MM:SS,mmm)
const formatTimeForSRT = (seconds: number): string => {
  const hours = Math.floor(seconds / 3600);
  const minutes = Math.floor((seconds % 3600) / 60);
  const secs = Math.floor(seconds % 60);
  const milliseconds = Math.floor((seconds % 1) * 1000);
  return `${hours.toString().padStart(2, "0")}:${minutes.toString().padStart(2, "0")}:${secs.toString().padStart(2, "0")},${milliseconds.toString().padStart(3, "0")}`;
};

// Format time for WebVTT (HH:MM:SS.mmm)
const formatTimeForVTT = (seconds: number): string => {
  const hours = Math.floor(seconds / 3600);
  const minutes = Math.floor((seconds % 3600) / 60);
  const secs = Math.floor(seconds % 60);
  const milliseconds = Math.floor((seconds % 1) * 1000);
  return `${hours.toString().padStart(2, "0")}:${minutes.toString().padStart(2, "0")}:${secs.toString().padStart(2, "0")}.${milliseconds.toString().padStart(3, "0")}`;
};

// Download subtitle file
export const downloadSubtitles = (content: string, filename: string) => {
  const blob = new Blob([content], { type: "text/plain;charset=utf-8" });
  const url = URL.createObjectURL(blob);
  const link = document.createElement("a");
  link.href = url;
  link.download = filename;
  document.body.appendChild(link);
  link.click();
  document.body.removeChild(link);
  URL.revokeObjectURL(url);
};

// Helper function to parse VTT time format
export const parseVTTTime = (timeStr: string): number => {
  const parts = timeStr.split(":");
  const seconds = parts[parts.length - 1].split(".");
  return (
    parseInt(parts[0]) * 3600 + // hours
    parseInt(parts[1]) * 60 + // minutes
    parseInt(seconds[0]) + // seconds
    parseInt(seconds[1] || "0") / 1000 // milliseconds
  );
};

// Download video with embedded subtitles using backend FFmpeg processing
export const downloadVideoWithSubtitles = async (
  videoFile: File,
  subtitleContent: string,
  filename: string,
  language: string = 'eng',
  format: 'srt' | 'webvtt' = 'srt',
  outputFormat: 'mp4' | 'mkv' = 'mp4'
) => {
  try {
    // Use the centralized API function
    const blob = await combineVideoWithSubtitles(videoFile, subtitleContent, language, format, outputFormat);

    // Create download link
    const url = URL.createObjectURL(blob);
    const link = document.createElement('a');
    link.href = url;
    link.download = filename;
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
    URL.revokeObjectURL(url);

  } catch (error) {
    console.error('Error combining video with subtitles:', error);
    throw new Error(`Failed to combine video with subtitles: ${error instanceof Error ? error.message : 'Unknown error'}`);
  }
};

// Format time helper function
export const formatTime = (seconds: number) => {
  const mins = Math.floor(seconds / 60);
  const secs = Math.floor(seconds % 60);
  return `${mins}:${secs.toString().padStart(2, "0")}`;
};