package link.roadio.riff.ui

import link.roadio.riff.indexer.core.media.MediaId
import link.roadio.riff.player.storage.PlaybackQueueKind
import link.roadio.riff.player.storage.PlaybackQueueSnapshot

/** Immutable worker result: main only installs already prepared queue identity and current metadata. */
internal data class PreparedQueuePresentation(
    val mediaIds: List<MediaId>,
    val index: Int,
    val track: BrowserItem?,
)

// AI-INTENT: A READY callback must not repeat a recursive source projection on the main looper.
// Keep the captured cohort alive and reuse the manual command's ordered references when available.
// https://wiki.271.pics/Riff/1-1-0/catalog-consumption#player-browse-representation
internal fun prepareQueuePresentation(
    root: BrowserItem,
    availableTracks: List<BrowserItem>,
    queue: PlaybackQueueSnapshot,
    contextTracks: List<BrowserItem>? = null,
): PreparedQueuePresentation {
    val order = queue.orderedOccurrences()
    val index = order.indexOfFirst { it.occurrenceId == queue.checkpoint.occurrenceId }.coerceAtLeast(0)
    val occurrence = order.getOrNull(index)
    val contextual =
        occurrence?.takeIf { queue.kind != PlaybackQueueKind.PERMANENT_PLAYLIST }?.let { item ->
            if (contextTracks != null) {
                contextTracks.getOrNull(item.ordinal)?.takeIf { it.mediaId == item.mediaId }
            } else {
                queueTrackForOccurrence(root, queue.contextKey, item.ordinal, item.mediaId)
            }
        }
    val track =
        contextual ?: occurrence?.mediaId?.let { media ->
            root.catalog?.let { it.track(media) } ?: availableTracks.firstOrNull { it.mediaId == media }
        }
    return PreparedQueuePresentation(order.map { it.mediaId }, index, track)
}