/**
 * Watch Progress Utilities
 * Centralized constants and helper functions for watch progress calculations
 */

/**
 * Completion threshold - content is marked as "completed" when reaching this percentage
 */
export const COMPLETION_THRESHOLD = 0.9; // 90%

/**
 * Minimum progress threshold - don't save progress below this to avoid accidental saves
 */
export const MIN_PROGRESS_THRESHOLD = 0.05; // 5%

/**
 * Significant position change threshold in seconds
 * Used to detect seeks and trigger saves
 */
export const SIGNIFICANT_POSITION_CHANGE = 30; // 30 seconds

/**
 * Backup save interval in milliseconds
 * How often to save progress during continuous playback
 */
export const BACKUP_SAVE_INTERVAL = 30000; // 30 seconds

/**
 * Calculate progress percentage from current position and total duration
 * @param currentSeconds Current playback position in seconds
 * @param totalSeconds Total content duration in seconds
 * @returns Progress percentage (0-100)
 */
export function calculateProgressPercentage(
  currentSeconds: number,
  totalSeconds: number
): number {
  if (!totalSeconds || totalSeconds <= 0) return 0;
  const percentage = (currentSeconds / totalSeconds) * 100;
  // Round to 2 decimal places and clamp between 0-100
  return Math.min(100, Math.max(0, Math.round(percentage * 100) / 100));
}

/**
 * Check if content is considered completed based on progress percentage
 * @param percentage Progress percentage (0-100)
 * @returns true if content is completed
 */
export function isCompleted(percentage: number): boolean {
  return percentage >= COMPLETION_THRESHOLD * 100;
}

/**
 * Check if content is considered completed based on position and duration
 * @param currentSeconds Current playback position in seconds
 * @param totalSeconds Total content duration in seconds
 * @returns true if content is completed
 */
export function isContentCompleted(
  currentSeconds: number,
  totalSeconds: number
): boolean {
  if (!totalSeconds || totalSeconds <= 0) return false;
  return currentSeconds / totalSeconds >= COMPLETION_THRESHOLD;
}

/**
 * Check if progress should be saved based on current percentage
 * @param percentage Progress percentage (0-100)
 * @returns true if progress should be saved
 */
export function shouldSaveProgress(percentage: number): boolean {
  return percentage >= MIN_PROGRESS_THRESHOLD * 100;
}

/**
 * Check if progress should be saved based on position and duration
 * @param currentSeconds Current playback position in seconds
 * @param totalSeconds Total content duration in seconds
 * @returns true if progress should be saved
 */
export function shouldSaveProgressByPosition(
  currentSeconds: number,
  totalSeconds: number
): boolean {
  if (!totalSeconds || totalSeconds <= 0) return false;
  return currentSeconds / totalSeconds >= MIN_PROGRESS_THRESHOLD;
}

/**
 * Format seconds into human-readable time string
 * @param seconds Duration in seconds
 * @returns Formatted time string (e.g., "1h 23m", "45m", "2m 30s")
 */
export function formatDuration(seconds: number): string {
  if (!seconds || seconds < 0) return '0m';

  const hours = Math.floor(seconds / 3600);
  const minutes = Math.floor((seconds % 3600) / 60);
  const remainingSeconds = Math.floor(seconds % 60);

  if (hours > 0) {
    if (minutes > 0) {
      return `${hours}h ${minutes}m`;
    }
    return `${hours}h`;
  }

  if (minutes > 0) {
    if (remainingSeconds > 0 && minutes < 10) {
      return `${minutes}m ${remainingSeconds}s`;
    }
    return `${minutes}m`;
  }

  return `${remainingSeconds}s`;
}

/**
 * Format remaining time for continue watching display
 * @param remainingSeconds Remaining duration in seconds
 * @returns Formatted string (e.g., "23 min left", "1 hr 10 min left")
 */
export function formatRemainingTime(remainingSeconds: number): string {
  if (!remainingSeconds || remainingSeconds < 0) return '';

  const hours = Math.floor(remainingSeconds / 3600);
  const minutes = Math.floor((remainingSeconds % 3600) / 60);

  if (hours > 0) {
    if (minutes > 0) {
      return `${hours} hr ${minutes} min left`;
    }
    return `${hours} hr left`;
  }

  if (minutes > 0) {
    return `${minutes} min left`;
  }

  return 'Less than 1 min left';
}

/**
 * Calculate remaining time from progress and total duration
 * @param currentSeconds Current playback position in seconds
 * @param totalSeconds Total content duration in seconds
 * @returns Remaining seconds
 */
export function calculateRemainingTime(
  currentSeconds: number,
  totalSeconds: number
): number {
  if (!totalSeconds || totalSeconds <= 0) return 0;
  return Math.max(0, totalSeconds - currentSeconds);
}

/**
 * Generate a unique key for progress entry (for Map lookups)
 * @param contentId Content ID
 * @param episodeId Optional episode ID for series
 * @returns Unique key string
 */
export function getProgressKey(contentId: string, episodeId?: string): string {
  return episodeId ? `${contentId}:${episodeId}` : contentId;
}

/**
 * Generate a unique ID for a progress entry
 * @param contentId Content ID
 * @param episodeId Optional episode ID for series
 * @returns Unique ID string
 */
export function generateProgressId(contentId: string, episodeId?: string): string {
  return episodeId ? `${contentId}-${episodeId}` : contentId;
}

/**
 * Check if position change is significant enough to trigger a save
 * @param previousPosition Previous playback position in seconds
 * @param currentPosition Current playback position in seconds
 * @returns true if change is significant (likely a seek)
 */
export function isSignificantPositionChange(
  previousPosition: number,
  currentPosition: number
): boolean {
  return Math.abs(currentPosition - previousPosition) > SIGNIFICANT_POSITION_CHANGE;
}