frontend/src/utils/transcriptionWarnings.ts

// Transcription limits and thresholds
// These constants are shared across components to ensure consistency

export const TRANSCRIPTION_LIMITS = {
  // Duration limits (in seconds)
  MIN_DURATION: 3,          // Minimum recommended duration for accuracy
  MAX_DURATION: 180,         // Maximum recommended duration (3 minutes)

  // File size limits (in MB)
  MAX_FILE_SIZE: 100,        // Maximum recommended file size
} as const;

export const WARNING_MESSAGES = {
  TOO_SHORT: {
    title: "Media Too Short",
    message: "Your media file is less than 3 seconds long. This may result in reduced transcription accuracy due to insufficient context for the AI model. For best results, use media files at least 30 seconds long.",
  },
  TOO_LONG: {
    title: "Media Too Long",
    message: "Your media file is longer than 3 minutes. This may exceed server resources and could result in processing failures or timeouts. Consider trimming your media to under 3 minutes for optimal results.",
  },
  VERY_LARGE_FILE: {
    title: "File Too Large",
    message: "Your file exceeds the recommended 100MB limit. This may cause upload failures or processing timeouts. Please use a smaller file or compress your media before uploading.",
  },
} as const;

type WarningType = keyof typeof WARNING_MESSAGES;

interface MediaInfo {
  file: File;
  duration?: number; // Duration in seconds, may not be available immediately
}

/**
 * Get the duration of a media file
 * Returns a promise that resolves with the duration in seconds
 */
export const getMediaDuration = (file: File): Promise<number> => {
  return new Promise((resolve, reject) => {
    const url = URL.createObjectURL(file);

    if (file.type.startsWith('video/')) {
      const video = document.createElement('video');
      video.preload = 'metadata';

      video.onloadedmetadata = () => {
        URL.revokeObjectURL(url);
        resolve(video.duration);
      };

      video.onerror = () => {
        URL.revokeObjectURL(url);
        reject(new Error('Failed to load video metadata'));
      };

      video.src = url;
    } else if (file.type.startsWith('audio/')) {
      const audio = document.createElement('audio');
      audio.preload = 'metadata';

      audio.onloadedmetadata = () => {
        URL.revokeObjectURL(url);
        resolve(audio.duration);
      };

      audio.onerror = () => {
        URL.revokeObjectURL(url);
        reject(new Error('Failed to load audio metadata'));
      };

      audio.src = url;
    } else {
      URL.revokeObjectURL(url);
      reject(new Error('Unsupported media type'));
    }
  });
};

/**
 * Check for transcription warnings based on file size and duration
 * Returns an array of warning types that should be shown to the user
 */
export const checkTranscriptionWarnings = (mediaInfo: MediaInfo): WarningType[] => {
  const warnings: WarningType[] = [];
  const { file, duration } = mediaInfo;

  // Check file size (convert to MB)
  const fileSizeMB = file.size / (1024 * 1024);

  if (fileSizeMB > TRANSCRIPTION_LIMITS.MAX_FILE_SIZE) {
    warnings.push('VERY_LARGE_FILE');
  }

  // Check duration if available
  if (duration !== undefined && !isNaN(duration)) {
    if (duration < TRANSCRIPTION_LIMITS.MIN_DURATION) {
      warnings.push('TOO_SHORT');
    } else if (duration > TRANSCRIPTION_LIMITS.MAX_DURATION) {
      warnings.push('TOO_LONG');
    }
  }

  return warnings;
};


/**
 * Format file size in a human-readable format
 */
export const formatFileSize = (bytes: number): string => {
  if (bytes === 0) return '0 Bytes';

  const k = 1024;
  const sizes = ['Bytes', 'KB', 'MB', 'GB'];
  const i = Math.floor(Math.log(bytes) / Math.log(k));

  return parseFloat((bytes / Math.pow(k, i)).toFixed(1)) + ' ' + sizes[i];
};

/**
 * Format duration in a human-readable format
 */
export const formatDuration = (seconds: number): string => {
  if (isNaN(seconds) || seconds < 0) return 'Unknown';

  const minutes = Math.floor(seconds / 60);
  const remainingSeconds = Math.floor(seconds % 60);

  if (minutes === 0) {
    return `${remainingSeconds}s`;
  } else {
    return `${minutes}m ${remainingSeconds}s`;
  }
};