/*
    2022-09-19 File created by Kari Laitinen
    2022-09-22 Last modification.

    (c) naturalprogramming.com

    This simple app contains a TextView and a Button.

    You can see how to use ConstraintSet to create the UI
    without XML.

    This is an Android app made of this single file.

    If you want to test this app, create an Android Kotlin project
    with the package name shown below. Then, store this file
    to the folder where MainActivity.kt is and make the following
    change to AndroidManifest.xml:
    android:name=".ButtonDemoNoXMLActivity"

    Useful links:

    https://www.youtube.com/watch?v=PyJRfHXUNbU

    Some 'warnings':
    - tab size in this file is 3 spaces
    - underscores are used in the names invented by the programmer
*/

package buttondemo.noxml

import android.content.Context
import android.graphics.Color
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.view.ViewGroup
import android.widget.Button
import android.widget.TextView
import androidx.constraintlayout.widget.ConstraintLayout
import androidx.constraintlayout.widget.ConstraintSet
import com.google.android.material.button.MaterialButton

class ButtonDemoConstraintLayout( context : Context)
   : ConstraintLayout( context )
{
   init
   {
      id = generateViewId()  // id for parent

      val basic_layout_params = ViewGroup.LayoutParams(
         ViewGroup.LayoutParams.MATCH_PARENT,
         ViewGroup.LayoutParams.MATCH_PARENT )

      //setLayoutParams( basic_layout_params )
      layoutParams = basic_layout_params

      setBackgroundColor( Color.LTGRAY )

      val constraint_set = ConstraintSet()

      constraint_set.clone( this )

      val changing_text = TextView( context )

      changing_text.text = "HELLO!"
      changing_text.textSize = 32F
      changing_text.id = View.generateViewId()

      addView( changing_text )

      constraint_set.constrainWidth( changing_text.id,
         ConstraintSet.WRAP_CONTENT )
      constraint_set.constrainHeight( changing_text.id,
         300 )

      constraint_set.centerHorizontally( changing_text.id, ConstraintSet.PARENT_ID )

      val button_to_press = MaterialButton( context )

      button_to_press.id = generateViewId()

      button_to_press.setBackgroundColor( 0xFF808000.toInt() ) // Olive color.
      button_to_press.setTextColor( Color.WHITE )
      button_to_press.textSize = 24F
      button_to_press.text = "PRESS"
      button_to_press.cornerRadius = 40  // Works only with MaterialButton, I guess.

      button_to_press.setOnClickListener{

         if ( changing_text.text == "HELLO!" )
         {
            changing_text.text = "WELL DONE!"
         }
         else
         {
            changing_text.text = "HELLO!"
         }
      }

      addView( button_to_press )

      constraint_set.constrainWidth( button_to_press.id,
         400 )
      constraint_set.constrainHeight( button_to_press.id,
         300 )

      /*
      // The following two connections center the button horizontally.
      constraint_set.connect( button_to_press.id, ConstraintSet.LEFT,
         ConstraintSet.PARENT_ID, ConstraintSet.LEFT )
      constraint_set.connect( button_to_press.id, ConstraintSet.RIGHT,
         ConstraintSet.PARENT_ID, ConstraintSet.RIGHT )
      */

      // The following seems to be an easier way for horizontal centering.
      constraint_set.centerHorizontally( button_to_press.id, ConstraintSet.PARENT_ID )

      // Instead of connecting, we'll do chaining.
      //constraint_set.connect( button_to_press.id, ConstraintSet.TOP,
        // changing_text.id, ConstraintSet.BOTTOM, 300 )

      val views_to_chain = intArrayOf( changing_text.id, button_to_press.id )

      constraint_set.createVerticalChain( ConstraintSet.PARENT_ID,
                                          ConstraintSet.TOP,
                                          ConstraintSet.PARENT_ID,
                                          ConstraintSet.BOTTOM,
                                          views_to_chain,
                                          null,
                                           ConstraintSet.CHAIN_PACKED )

      constraint_set.applyTo( this )
   }
}


class ButtonDemoNoXMLActivity : AppCompatActivity()
{
   override fun onCreate(savedInstanceState: Bundle?)
   {
      super.onCreate(savedInstanceState)

      val button_demo_constraint_layout = ButtonDemoConstraintLayout( this )
      setContentView( button_demo_constraint_layout )
   }
}