package link.roadio.riff.ui

import java.text.Normalizer
import java.util.Locale

/** Prepared on the A-Z/reload worker. UI reads never start sorting or wait for its monitor.
 * https://wiki.271.pics/Riff/1-1-0/catalog-consumption#prepared-collection-views
 */
internal class OrderedBrowserRows(
    private val source: List<BrowserItem>,
    private val ignoreLeadingArticles: Boolean,
    private val foldersFirst: Boolean,
) : BrowserRows() {
    private data class Prepared(
        val keys: List<BrowserRowKey>,
        val order: IntArray,
    )

    @Volatile private var prepared: Prepared? = null
    override val ready get() = prepared != null && (source as? BrowserRows)?.ready != false
    override val size get() = source.size

    @Synchronized override fun prepare() {
        if (prepared != null) return
        (source as? BrowserRows)?.prepare()
        val keys = source.indices.map(source::rowKey)
        val normalized =
            keys.map {
                Normalizer
                    .normalize(
                        browseComparisonName(it.comparisonName, ignoreLeadingArticles),
                        Normalizer.Form.NFKC,
                    ).lowercase(Locale.ROOT)
            }
        val compare =
            compareBy<Int> {
                normalized[it]
            }.thenBy { keys[it].comparisonName }.thenBy { keys[it].genreId }.thenBy { keys[it].id }
        val order =
            if (foldersFirst) {
                keys.indices.filter { keys[it].kind == BrowserKind.FOLDER }.sortedWith(compare) +
                    keys.indices.filter { keys[it].kind != BrowserKind.FOLDER }
            } else {
                keys.indices.sortedWith(compare)
            }
        prepared = Prepared(keys, order.toIntArray())
    }

    private fun data(): Prepared = prepared ?: error("Unprepared browse order must not be read on UI")

    override fun key(index: Int) = data().let { it.keys[it.order[index]] }

    override fun rowId(index: Int) = key(index).id

    override fun mediaId(index: Int) = data().order[index].let { if (source is BrowserRows) source.mediaId(it) else source[it].mediaId }

    override fun playable(index: Int) = data().order[index].let { if (source is BrowserRows) source.playable(it) else source[it].playable }

    override fun get(index: Int) = source[data().order[index]]

    override fun findRow(id: String) = source.rowById(id)
}

internal fun List<BrowserItem>.orderedRows(
    ignoreLeadingArticles: Boolean,
    alphabetical: Boolean,
    foldersFirst: Boolean,
): List<BrowserItem> = if (!alphabetical && !foldersFirst) this else OrderedBrowserRows(this, ignoreLeadingArticles, foldersFirst)