import type { TimelineTrack } from "@/lib/timeline/types";
import { rippleShiftElements } from "./shift";

export interface RippleAdjustment {
	trackId: string;
	afterTime: number;
	shiftAmount: number;
}

export function applyRippleAdjustments({
	tracks,
	adjustments,
}: {
	tracks: TimelineTrack[];
	adjustments: RippleAdjustment[];
}): TimelineTrack[] {
	if (adjustments.length === 0) {
		return tracks;
	}

	const adjustmentsByTrack = new Map<string, RippleAdjustment[]>();
	for (const adjustment of adjustments) {
		const trackAdjustments = adjustmentsByTrack.get(adjustment.trackId) ?? [];
		trackAdjustments.push(adjustment);
		adjustmentsByTrack.set(adjustment.trackId, trackAdjustments);
	}

	return tracks.map((track) =>
		applyTrackRippleAdjustments({
			track,
			adjustments: adjustmentsByTrack.get(track.id) ?? [],
		}),
	);
}

function applyTrackRippleAdjustments<
	TElement extends TimelineTrack["elements"][number],
	TTrack extends TimelineTrack & { elements: TElement[] },
>({
	track,
	adjustments,
}: {
	track: TTrack;
	adjustments: RippleAdjustment[];
}): TTrack {
	if (adjustments.length === 0) {
		return track;
	}

	const sortedAdjustments = [...adjustments].sort(
		(firstAdjustment, secondAdjustment) =>
			secondAdjustment.afterTime - firstAdjustment.afterTime,
	);

	let elements: TElement[] = track.elements;
	for (const adjustment of sortedAdjustments) {
		elements = rippleShiftElements({
			elements,
			afterTime: adjustment.afterTime,
			shiftAmount: adjustment.shiftAmount,
		});
	}

	return { ...track, elements };
}