import type {MediaParserController} from '../../controller/media-parser-controller';
import type {M3uState} from '../../state/m3u-state';
import type {
	MediaParserOnVideoSample,
	MediaParserVideoSample,
} from '../../webcodec-sample-types';
import {WEBCODECS_TIMESCALE} from '../../webcodecs-timescale';

export const considerSeekBasedOnChunk = async ({
	sample,
	parentController,
	childController,
	callback,
	m3uState,
	playlistUrl,
	subtractChunks,
	chunkIndex,
}: {
	sample: MediaParserVideoSample;
	callback: MediaParserOnVideoSample;
	parentController: MediaParserController;
	childController: MediaParserController;
	playlistUrl: string;
	m3uState: M3uState;
	subtractChunks: number;
	chunkIndex: number | null;
}) => {
	const pendingSeek = m3uState.getSeekToSecondsToProcess(playlistUrl);
	// If there is not even a seek to consider, just call the callback
	if (pendingSeek === null) {
		await callback(sample);
		return;
	}

	const timestamp = Math.min(
		sample.decodingTimestamp / WEBCODECS_TIMESCALE,
		sample.timestamp / WEBCODECS_TIMESCALE,
	);

	// Already too far, now we should go to the previous chunk
	if (
		timestamp > pendingSeek.targetTime &&
		chunkIndex !== null &&
		chunkIndex > 0
	) {
		m3uState.setNextSeekShouldSubtractChunks(playlistUrl, subtractChunks + 1);
		parentController.seek(pendingSeek.targetTime);

		return;
	}

	// We are good, we have not gone too far! Don't emit sample and seek and clear pending seek
	childController.seek(pendingSeek.targetTime);
	m3uState.setNextSeekShouldSubtractChunks(playlistUrl, 0);
	m3uState.setSeekToSecondsToProcess(playlistUrl, null);
};