import type {TSequence} from 'remotion';

// The goal for this function is to calculate an as unique as possible identifier
// for a sequence based on it's properties. A sequence can be registered multiple times
// from main preview and from thumbnails and we use this to deduplicate it.
// This is why we don't use `id` properties as they will
// differ as a hash.
export const getTimelineSequenceHash = (
	sequence: TSequence,
	allSequences: TSequence[],
	hashesUsedInRoot: {
		[rootId: string]: string[];
	},
	cache: {[sequenceId: string]: string},
): string => {
	if (cache[sequence.id]) {
		return cache[sequence.id];
	}

	const parent = allSequences.find((a) => a.id === sequence.parent);
	const baseHash = [
		parent
			? getTimelineSequenceHash(parent, allSequences, hashesUsedInRoot, cache)
			: null,
		sequence.displayName,
		sequence.duration,
		sequence.from,
		sequence.type,
		sequence.type === 'audio' ? sequence.src : null,
		sequence.type === 'audio' ? sequence.volume : null,
		sequence.type === 'video' ? sequence.src : null,
		sequence.type === 'video' ? sequence.volume : null,
	].join('-');
	const actualHash =
		baseHash +
		hashesUsedInRoot[sequence.rootId].filter((h) => h === baseHash).length;
	hashesUsedInRoot[sequence.rootId].push(baseHash);
	cache[sequence.id] = actualHash;
	return actualHash;
};