Pixelcat-App-Android/app/src/main/kotlin/at/connyduck/pixelcat/util/ViewBindingExtensions.kt

package at.connyduck.pixelcat.util

import android.view.LayoutInflater
import android.view.View
import androidx.appcompat.app.AppCompatActivity
import androidx.fragment.app.Fragment
import androidx.lifecycle.DefaultLifecycleObserver
import androidx.lifecycle.Lifecycle
import androidx.lifecycle.LifecycleOwner
import androidx.viewbinding.ViewBinding
import kotlin.properties.ReadOnlyProperty
import kotlin.reflect.KProperty

/**
 * https://medium.com/@Zhuinden/simple-one-liner-viewbinding-in-fragments-and-activities-with-kotlin-961430c6c07c
 */

inline fun <T : ViewBinding> AppCompatActivity.viewBinding(
    crossinline bindingInflater: (LayoutInflater) -> T
) = lazy(LazyThreadSafetyMode.NONE) {
    bindingInflater(layoutInflater)
}

class FragmentViewBindingDelegate<T : ViewBinding>(
    val fragment: Fragment,
    val viewBindingFactory: (View) -> T
) : ReadOnlyProperty<Fragment, T> {
    private var binding: T? = null

    init {
        fragment.lifecycle.addObserver(
            object : DefaultLifecycleObserver {
                override fun onCreate(owner: LifecycleOwner) {
                    fragment.viewLifecycleOwnerLiveData.observe(
                        fragment
                    ) { t ->
                        t?.lifecycle?.addObserver(
                            object : DefaultLifecycleObserver {
                                override fun onDestroy(owner: LifecycleOwner) {
                                    binding = null
                                }
                            }
                        )
                    }
                }
            }
        )
    }

    override fun getValue(thisRef: Fragment, property: KProperty<*>): T {
        val binding = binding
        if (binding != null) {
            return binding
        }

        val lifecycle = fragment.viewLifecycleOwner.lifecycle
        if (!lifecycle.currentState.isAtLeast(Lifecycle.State.INITIALIZED)) {
            throw IllegalStateException("Should not attempt to get bindings when Fragment views are destroyed.")
        }

        return viewBindingFactory(thisRef.requireView()).also { this@FragmentViewBindingDelegate.binding = it }
    }
}

fun <T : ViewBinding> Fragment.viewBinding(viewBindingFactory: (View) -> T) =
    FragmentViewBindingDelegate(this, viewBindingFactory)