import android.view.Gravity
import android.view.View
import android.widget.PopupWindow
import android.widget.SeekBar
import org.jetbrains.anko.dip

/**
 * Wrapper adds floating view above seek bar. It follows thumb when user touches it.
 * Wrapper sets SeekBar.OnSeekBarChangeListener so if you need to track events from this listener,
 * set callbacks available in wrapper: [SeekBarFloatingWrapper.progressChanged],
 * [SeekBarFloatingWrapper.startTrackTouch], [SeekBarFloatingWrapper.stopTrackTouch]
 *
 * You can set custom animation style.
 * @see [PopupWindow]
 * @see [PopupWindow.setAnimationStyle]
 * @see [SeekBar]
 *
 * Created by Lucas on 2017-03-25.
 */
class SeekBarFloatingWrapper {

    private lateinit var popup: PopupWindow

    lateinit var seekBar: SeekBar
    var width = 0
        set(value) {
            field = seekBar.context.dip(value)
        }
    var height = 0
        set(value) {
            field = seekBar.context.dip(value)
        }

    var progressChanged: (seekBar: SeekBar,
                          progress: Int,
                          fromUser: Boolean) -> Unit = { _, _, _ -> }
    var startTrackTouch: () -> Unit = {}
    var stopTrackTouch: () -> Unit = {}

    companion object {
        const val SIZE_UNCHANGED = -1
        const val DEFAULT_ANIMATION = 0
    }

    fun wrap(seekBar: SeekBar, contentView: View): SeekBarFloatingWrapper {
        this.seekBar = seekBar
        width = seekBar.context.dip(120)
        height = seekBar.context.dip(72)
        popup = createPopupWindow(contentView)
        this.seekBar.setOnSeekBarChangeListener(object : SeekBar.OnSeekBarChangeListener {
            override fun onProgressChanged(seekBar: SeekBar, progress: Int, fromUser: Boolean) {
                if (fromUser) {
                    popup.update(calcPreviewPosition(seekBar, popup.width),
                            seekBar.top,
                            SIZE_UNCHANGED,
                            SIZE_UNCHANGED)

                }
                progressChanged(seekBar, progress, fromUser)
            }

            override fun onStartTrackingTouch(seekBar: SeekBar) {
                if (!popup.isShowing) {
                    popup.showAtLocation(popup.contentView,
                            Gravity.NO_GRAVITY,
                            calcPreviewPosition(seekBar, popup.width),
                            seekBar.top)
                }
                startTrackTouch
            }

            override fun onStopTrackingTouch(seekBar: SeekBar) {
                if (popup.isShowing) popup.dismiss()
                stopTrackTouch
            }
        })
        return this
    }

    fun setAnimationStyle(animationStyle: Int) {
        if (animationStyle != DEFAULT_ANIMATION) popup.animationStyle = animationStyle
    }

    private fun createPopupWindow(content: View, animationStyle: Int = DEFAULT_ANIMATION): PopupWindow {
        val popup = PopupWindow()
        popup.contentView = content
        if (animationStyle != DEFAULT_ANIMATION) popup.animationStyle = animationStyle
        popup.width = width
        popup.height = height
        return popup
    }

    private fun calcPreviewPosition(seekBar: SeekBar, popupWidth: Int): Int {
        val scale = seekBar.progress / seekBar.max.toFloat()
        val parent = seekBar.parent as View
        val x = (parent.width - popupWidth) * scale
        return x.toInt()
    }
}