package leakcanary

import android.annotation.SuppressLint
import android.app.Activity
import android.app.Application
import android.os.Build.VERSION
import android.os.Bundle
import android.view.View
import android.view.ViewGroup
import android.widget.FrameLayout
import curtains.Curtains
import curtains.OnRootViewRemovedListener
import leakcanary.internal.friendly.checkMainThread
import leakcanary.internal.friendly.isMainThread
import leakcanary.internal.friendly.mainHandler
import leakcanary.internal.friendly.noOpDelegate
import leakcanary.internal.onAndroidXFragmentViewDestroyed
import shark.SharkLog

/**
 * @see [AndroidLeakFixes.VIEW_LOCATION_HOLDER].
 */
@SuppressLint("NewApi")
object ViewLocationHolderLeakFix {

  private var groupAndOutChildren: Pair<ViewGroup, ArrayList<View>>? = null
  private var failedClearing = false

  internal fun applyFix(application: Application) {
    if (VERSION.SDK_INT != 28) {
      return
    }
    // Takes care of child windows (e.g. dialogs)
    Curtains.onRootViewsChangedListeners += OnRootViewRemovedListener {
      if (isMainThread) {
        uncheckedClearStaticPool(application)
      } else {
        mainHandler.post {
          uncheckedClearStaticPool(application)
        }
      }
    }
    application.registerActivityLifecycleCallbacks(object : Application.ActivityLifecycleCallbacks
    by noOpDelegate() {

      override fun onActivityCreated(
        activity: Activity,
        savedInstanceState: Bundle?
      ) {
        activity.onAndroidXFragmentViewDestroyed {
          uncheckedClearStaticPool(application)
        }
      }
    })
  }

  /**
   * Clears the ViewGroup.ViewLocationHolder.sPool static pool.
   */
  fun clearStaticPool(application: Application) {
    checkMainThread()
    if (VERSION.SDK_INT != 28) {
      return
    }
    uncheckedClearStaticPool(application)
  }

  private fun uncheckedClearStaticPool(application: Application) {
    if (failedClearing) {
      return
    }
    try {
      if (groupAndOutChildren == null) {
        val viewGroup = FrameLayout(application)
        // ViewLocationHolder.MAX_POOL_SIZE = 32
        for (i in 0 until 32) {
          val childView = View(application)
          viewGroup.addView(childView)
        }
        groupAndOutChildren = viewGroup to ArrayList()
      }
      val (group, outChildren) = groupAndOutChildren!!
      group.addChildrenForAccessibility(outChildren)
    } catch (ignored: Throwable) {
      SharkLog.d(ignored) {
        "Failed to clear ViewLocationHolder leak, will not try again."
      }
      failedClearing = true
    }
  }
}