App/player/handlers.ts

import { Progress, State } from "react-native-track-player";
import { JellifyTrack } from "../types/JellifyTrack";
import { PlaystateApi } from "@jellyfin/sdk/lib/generated-client/api/playstate-api";
import { convertSecondsToRunTimeTicks } from "../helpers/runtimeticks";

export async function handlePlaybackState(sessionId: string, playstateApi: PlaystateApi, track: JellifyTrack, state: State) {
    switch (state) {            
        case (State.Playing) : {
            console.debug("Report playback started")
            await playstateApi.reportPlaybackStart({
                playbackStartInfo: {
                    SessionId: sessionId,
                    ItemId: track.item.Id,
                }
            });
            break;
        }
        
        case (State.Ended) :
        case (State.Paused) :
        case (State.Stopped) : {
            console.debug("Report playback stopped")
            await playstateApi.reportPlaybackStopped({
                playbackStopInfo: {
                    SessionId: sessionId,
                    ItemId: track.item.Id,
                }
            });
            break;
        }

        default : {
            return;
        }
    }
}

export async function handlePlaybackProgressUpdated(sessionId: string, playstateApi: PlaystateApi, track: JellifyTrack, progress: Progress) {
    if (Math.floor(progress.duration - progress.position) === 5) {
        console.debug("Track finished, scrobbling...");
        await playstateApi.reportPlaybackStopped({
            playbackStopInfo: {
                SessionId: sessionId,
                ItemId: track.item.Id,
                PositionTicks: convertSecondsToRunTimeTicks(track.duration!)
            }
        });
    } else {
        // DO NOTHING, reporting playback will just eat up power
        // Jellyfin can keep track of progress, we're going to intentionally
        // only give it the "greatest hits" (i.e., anything that involves user interaction)
        // console.debug("Reporting playback position");
        // await playstateApi.reportPlaybackProgress({
        //     playbackProgressInfo: {
        //         SessionId: sessionId,
        //         ItemId: track.ItemId,
        //         PositionTicks: convertSecondsToRunTimeTicks(progress.position)
        //     }
        // });
    };
}