import androidx.compose.ui.unit.dp

import androidx.activity.compose.setContent

import android.os.Bundle

import androidx.activity.ComponentActivity

import androidx.compose.material.Surface

import androidx.compose.material.Text

import androidx.compose.runtime.Composable

import androidx.compose.ui.Modifier

import androidx.compose.foundation.Canvas

import androidx.compose.foundation.layout.Box

import androidx.compose.foundation.layout.fillMaxSize

import androidx.compose.foundation.layout.size

import androidx.compose.material.*

import androidx.compose.runtime.*

import androidx.compose.ui.Alignment

import androidx.compose.ui.geometry.Offset

import androidx.compose.ui.geometry.Size

import androidx.compose.ui.graphics.Color

import androidx.compose.ui.graphics.PointMode

import androidx.compose.ui.graphics.StrokeCap

import androidx.compose.ui.graphics.drawscope.Stroke

import androidx.compose.ui.layout.onSizeChanged

import androidx.compose.ui.text.font.FontWeight

import androidx.compose.ui.unit.Dp

import androidx.compose.ui.unit.IntSize

import androidx.compose.ui.unit.sp

import kotlinx.coroutines.delay

import kotlin.math.PI

import kotlin.math.cos

import kotlin.math.sin

class MainActivity : ComponentActivity() {

 override fun onCreate(savedInstanceState: Bundle?) {

 super.onCreate(savedInstanceState)

 setContent {

  Surface(

  color = Color(0xFF101010),

  modifier = Modifier.fillMaxSize()

  ) {

  Box(

   contentAlignment = Alignment.Center

  ) {

   // call the function Timer

   // and pass the values

   // it is defined below.

   Timer(

   totalTime = 100L * 1000L,

   handleColor = Color.Green,

   inactiveBarColor = Color.DarkGray,

   activeBarColor = Color(0xFF37B900),

   modifier = Modifier.size(200.dp)

   )

  }

  }

 }

 }

}

// create a composable to

// Draw arc and handle

@Composable

fun Timer(

 // total time of the timer

 totalTime: Long,

 // circular handle color

 handleColor: Color,

 // color of inactive bar / progress bar

 inactiveBarColor: Color,

 // color of active bar

 activeBarColor: Color,

 modifier: Modifier = Modifier,

 // set initial value to 1

 initialValue: Float = 1f,

 strokeWidth: Dp = 5.dp

) {

 // create variable for

 // size of the composable

 var size by remember {

 mutableStateOf(IntSize.Zero)

 }

 // create variable for value

 var value by remember {

 mutableStateOf(initialValue)

 }

 // create variable for current time

 var currentTime by remember {

 mutableStateOf(totalTime)

 }

 // create variable for isTimerRunning

 var isTimerRunning by remember {

 mutableStateOf(false)

 }

 LaunchedEffect(key1 = currentTime, key2 = isTimerRunning) {

 if(currentTime > 0 && isTimerRunning) {

  delay(100L)

  currentTime -= 100L

  value = currentTime / totalTime.toFloat()

 }

 }

 Box(

 contentAlignment = Alignment.Center,

 modifier = modifier

  .onSizeChanged {

  size = it

  }

 ) {

 // draw the timer

 Canvas(modifier = modifier) {

  // draw the inactive arc with following parameters

  drawArc(

  color = inactiveBarColor, // assign the color

  startAngle = -215f, // assign the start angle

  sweepAngle = 250f, // arc angles

  useCenter = false, // prevents our arc to connect at te ends

  size = Size(size.width.toFloat(), size.height.toFloat()),

  // to make ends of arc round

  style = Stroke(strokeWidth.toPx(), cap = StrokeCap.Round)

  )

  // draw the active arc with following parameters

  drawArc(

  color = activeBarColor, // assign the color

  startAngle = -215f, // assign the start angle

  sweepAngle = 250f * value, // reduce the sweep angle

      // with the current value

  useCenter = false, // prevents our arc to connect at te ends

  size = Size(size.width.toFloat(), size.height.toFloat()),

  // to make ends of arc round

  style = Stroke(strokeWidth.toPx(), cap = StrokeCap.Round)

  )

  // calculate the value from arc pointer position

  val center = Offset(size.width / 2f, size.height / 2f)

  val beta = (250f * value + 145f) * (PI / 180f).toFloat()

  val r = size.width / 2f

  val a = cos(beta) * r

  val b = sin(beta) * r

  // draw the circular pointer/ cap

  drawPoints(

  listOf(Offset(center.x + a, center.y + b)),

  pointMode = PointMode.Points,

  color = handleColor,

  strokeWidth = (strokeWidth * 3f).toPx(),

  cap = StrokeCap.Round // make the pointer round

  )

 }

 // add value of the timer

 Text(

  text = (currentTime / 1000L).toString(),

  fontSize = 44.sp,

  fontWeight = FontWeight.Bold,

  color = Color.White

 )

 // create button to start or stop the timer

 Button(

  onClick = {

  if(currentTime <= 0L) {

   currentTime = totalTime

   isTimerRunning = true

  } else {

   isTimerRunning = !isTimerRunning

  }

  },

  modifier = Modifier.align(Alignment.BottomCenter),

  // change button color

  colors = ButtonDefaults.buttonColors(

  backgroundColor = if (!isTimerRunning || currentTime <= 0L) {

   Color.Green

  } else {

   Color.Red

  }

  )

 ) {

  Text(

  // change the text of button based on values

  text = if (isTimerRunning && currentTime >= 0L) "Stop"

  else if (!isTimerRunning && currentTime >= 0L) "Start"

  else "Restart"

  )

 }

 }

}