fedilab-Android-App/doubletapplayerview/src/main/java/com/github/vkay94/dtpv/youtube/views/YouTubeSecondsView.kt

package com.github.vkay94.dtpv.youtube.views

import android.animation.ValueAnimator
import android.content.Context
import android.util.AttributeSet
import android.view.LayoutInflater
import android.widget.ImageView
import android.widget.LinearLayout
import android.widget.TextView
import androidx.annotation.DrawableRes
import androidx.constraintlayout.widget.ConstraintLayout
import androidx.core.animation.doOnEnd
import androidx.core.animation.doOnStart
import com.github.vkay94.dtpv.R

/**
 * Layout group which handles the icon animation while forwarding and rewinding.
 *
 * Since it's based on view's alpha the fading effect is more fluid (more YouTube-like) than
 * using static drawables, especially when [cycleDuration] is low.
 *
 * Used by [YouTubeOverlay][com.github.vkay94.dtpv.youtube.YouTubeOverlay].
 */
class SecondsView(context: Context, attrs: AttributeSet?) :
    ConstraintLayout(context, attrs) {

    private var trianglesContainer: LinearLayout
    private var secondsTextView: TextView
    private var icon1: ImageView
    private var icon2: ImageView
    private var icon3: ImageView

    init {
        LayoutInflater.from(context).inflate(R.layout.yt_seconds_view, this, true)

        trianglesContainer = findViewById(R.id.triangle_container)
        secondsTextView = findViewById(R.id.tv_seconds)
        icon1 = findViewById(R.id.icon_1)
        icon2 = findViewById(R.id.icon_2)
        icon3 = findViewById(R.id.icon_3)
    }

    /**
     * Defines the duration for a full cycle of the triangle animation.
     * Each animation step takes 20% of it.
     */
    var cycleDuration: Long = 750L
        set(value) {
            firstAnimator.duration = value / 5
            secondAnimator.duration = value / 5
            thirdAnimator.duration = value / 5
            fourthAnimator.duration = value / 5
            fifthAnimator.duration = value / 5
            field = value
        }

    /**
     * Sets the `TextView`'s seconds text according to the device`s language.
     */
    var seconds: Int = 0
        set(value) {
            secondsTextView.text = context.resources.getQuantityString(
                R.plurals.quick_seek_x_second, value, value
            )
            field = value
        }

    /**
     * Mirrors the triangles depending on what kind of type should be used (forward/rewind).
     */
    var isForward: Boolean = true
        set(value) {
            trianglesContainer.rotation = if (value) 0f else 180f
            field = value
        }

    val textView: TextView
        get() = secondsTextView

    @DrawableRes
    var icon: Int = R.drawable.ic_play_triangle
        set(value) {
            if (value > 0) {
                icon1.setImageResource(value)
                icon2.setImageResource(value)
                icon3.setImageResource(value)
            }
            field = value
        }

    /**
     * Starts the triangle animation
     */
    fun start() {
        stop()
        firstAnimator.start()
    }

    /**
     * Stops the triangle animation
     */
    fun stop() {
        firstAnimator.cancel()
        secondAnimator.cancel()
        thirdAnimator.cancel()
        fourthAnimator.cancel()
        fifthAnimator.cancel()
        reset()
    }

    private fun reset() {
        icon1.alpha = 0f
        icon2.alpha = 0f
        icon3.alpha = 0f
    }

    private val firstAnimator: ValueAnimator by lazy {
        ValueAnimator.ofFloat(0f, 1f).setDuration(cycleDuration / 5).apply {
            doOnStart {
                icon1.alpha = 0f
                icon2.alpha = 0f
                icon3.alpha = 0f
            }
            addUpdateListener {
                icon1.alpha = (it.animatedValue as Float)
            }

            doOnEnd {
                secondAnimator.start()
            }
        }
    }

    private val secondAnimator: ValueAnimator by lazy {
        ValueAnimator.ofFloat(0f, 1f).setDuration(cycleDuration / 5).apply {
            doOnStart {
                icon1.alpha = 1f
                icon2.alpha = 0f
                icon3.alpha = 0f
            }
            addUpdateListener {
                icon2.alpha = (it.animatedValue as Float)
            }
            doOnEnd {
                thirdAnimator.start()
            }
        }
    }

    private val thirdAnimator: ValueAnimator by lazy {
        ValueAnimator.ofFloat(0f, 1f).setDuration(cycleDuration / 5).apply {
            doOnStart {
                icon1.alpha = 1f
                icon2.alpha = 1f
                icon3.alpha = 0f
            }
            addUpdateListener {
                icon1.alpha =
                    1f - icon3.alpha // or 1f - it (t3.alpha => all three stay a little longer together)
                icon3.alpha = (it.animatedValue as Float)
            }
            doOnEnd {
                fourthAnimator.start()
            }
        }

    }

    private val fourthAnimator: ValueAnimator by lazy {
        ValueAnimator.ofFloat(0f, 1f).setDuration(cycleDuration / 5).apply {
            doOnStart {
                icon1.alpha = 0f
                icon2.alpha = 1f
                icon3.alpha = 1f
            }
            addUpdateListener {
                icon2.alpha = 1f - (it.animatedValue as Float)
            }
            doOnEnd {
                fifthAnimator.start()
            }

        }
    }

    private val fifthAnimator: ValueAnimator by lazy {
        ValueAnimator.ofFloat(0f, 1f).setDuration(cycleDuration / 5).apply {
            doOnStart {
                icon1.alpha = 0f
                icon2.alpha = 0f
                icon3.alpha = 1f
            }
            addUpdateListener {
                icon3.alpha = 1f - (it.animatedValue as Float)
            }
            doOnEnd {
                firstAnimator.start()
            }
        }
    }
}