frontend/src/utils/trackUtils.ts

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

export interface SegmentWithTrack extends AlignedSegment {
  track: number;
}

/**
 * Assigns track numbers to segments to avoid overlaps
 * Segments always try to use the lowest available track (starting from track 0)
 */
export function assignTracksToSegments(segments: AlignedSegment[]): SegmentWithTrack[] {
  if (segments.length === 0) return [];

  // Sort segments by start time to process them in chronological order
  const sortedSegments = [...segments].sort((a, b) => a.start - b.start);

  // Track the end time of the last segment on each track
  const trackEndTimes: number[] = [];

  const segmentsWithTracks: SegmentWithTrack[] = sortedSegments.map((segment) => {
    // Find the lowest available track (starting from track 0)
    let assignedTrack = 0;

    // Check each existing track to see if this segment can fit
    for (let i = 0; i < trackEndTimes.length; i++) {
      if (trackEndTimes[i] <= segment.start) {
        // This track is available (previous segment has ended)
        assignedTrack = i;
        break;
      }
    }

    // If no existing track is available, use a new track
    if (assignedTrack === 0 && trackEndTimes.length > 0 && trackEndTimes[0] > segment.start) {
      assignedTrack = trackEndTimes.length;
    }

    // Update the end time for the assigned track
    if (assignedTrack >= trackEndTimes.length) {
      trackEndTimes.push(segment.end);
    } else {
      trackEndTimes[assignedTrack] = segment.end;
    }

    return {
      ...segment,
      track: assignedTrack,
    };
  });

  // Sort back to original order (by index in the original array)
  return segmentsWithTracks.sort((a, b) => {
    const aIndex = segments.findIndex(s => s === a);
    const bIndex = segments.findIndex(s => s === b);
    return aIndex - bIndex;
  });
}

/**
 * Calculate the total number of tracks needed
 */
export function getMaxTrackCount(segmentsWithTracks: SegmentWithTrack[]): number {
  if (segmentsWithTracks.length === 0) return 1;
  return Math.max(...segmentsWithTracks.map(s => s.track)) + 1;
}

/**
 * Calculate the height needed for the timeline based on track count
 */
export function getTimelineHeight(trackCount: number, isEditMode: boolean): number {
  const baseHeight = 60; // Minimum height for timeline controls
  const trackHeight = isEditMode ? 40 : 32; // Height per track
  const padding = 16; // Top and bottom padding

  return baseHeight + (trackCount * trackHeight) + padding;
}