package com.suno.android.media.hooks.preload

import androidx.annotation.OptIn
import androidx.media3.common.C
import androidx.media3.common.util.UnstableApi
import androidx.media3.exoplayer.source.preload.DefaultPreloadManager
import androidx.media3.exoplayer.source.preload.TargetPreloadStatusControl
import com.suno.android.media.HooksFeed
import java.util.concurrent.atomic.AtomicInteger
import javax.inject.Inject
import javax.inject.Singleton

private const val PRELOAD_DISTANCE = 5
private const val AGGRESSIVE_PRELOAD_DURATION_MS = 5_000L
private const val MEDIUM_PRELOAD_DURATION_MS = 3_000L
private const val LIGHT_PRELOAD_DURATION_MS = 1_000L

/**
 * Controls preload strategy for hooks feed videos based on distance from current playing video.
 */
@OptIn(UnstableApi::class)
@Singleton
@HooksFeed
class HooksFeedPreloadStatusControl @Inject constructor() :
    TargetPreloadStatusControl<Int, DefaultPreloadManager.PreloadStatus> {
    private val currentlyPlayingIndex = AtomicInteger(C.INDEX_UNSET)

    override fun getTargetPreloadStatus(
        index: Int,
    ): DefaultPreloadManager.PreloadStatus? {
        val distance = index - currentlyPlayingIndex.get()
        val isEligibleForPreload = distance in 1..PRELOAD_DISTANCE
        return if (isEligibleForPreload) {
            val duration = when (distance) {
                1 -> AGGRESSIVE_PRELOAD_DURATION_MS // Next video - aggressive preload
                2 -> MEDIUM_PRELOAD_DURATION_MS // 2 videos away - medium preload
                else -> LIGHT_PRELOAD_DURATION_MS // 3+ videos away - light preload
            }
            DefaultPreloadManager.PreloadStatus.specifiedRangeLoaded(duration)
        } else {
            null
        }
    }

    fun updateCurrentlyPlayingIndex(
        index: Int,
    ) {
        currentlyPlayingIndex.set(index)
    }

    fun getCurrentlyPlayingIndex(): Int = currentlyPlayingIndex.get()
}