// RandomCircles Example
// Source code file: MainActivity.kt
// Draw 100 random circles using 7 colors.
// Redraw 100 more random circles when
// the button is clicked.

package it372.ssmith.randomcircles
import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.activity.enableEdgeToEdge
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.padding
import androidx.compose.runtime.Composable
import androidx.compose.ui.Modifier
import androidx.compose.foundation.Canvas
import androidx.compose.foundation.background
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.size
import androidx.compose.material3.Button
import androidx.compose.material3.Slider
import androidx.compose.material3.Text
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.draw.clipToBounds
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.drawscope.Stroke
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        setContent {
            MainLayout()
        }
    }
}

@Composable
fun MainLayout( ) {
    // When trigger is changed by the Button onClick lambda,
    // the Canvas is recomposed so that the circles are
    // redrawn
    var trigger by remember { mutableStateOf(0)}
    Column(
        modifier = Modifier.padding(20.dp)
            .background(Color(0xFFE0E0E0))
            .fillMaxSize(),
        horizontalAlignment = Alignment.CenterHorizontally
    )
    {
        // Click Button to redraw random circles
        Button(
            onClick = {
                trigger++;
            },
            modifier = Modifier.padding(all = 15.dp)
        )
        {
            Text("Draw Circles", fontSize = 30.sp)
        }
        Canvas(
            modifier = Modifier
                .padding(10.dp)
                .size(350.dp, 350.dp)
                .background(Color(0xFFC0C0C0))
                .clipToBounds( )
                .fillMaxSize( ))
        {
            // onDraw lambda, which recomposes the
            // Canvas and redraws the circles when
            // trigger is updated.
            var currentTrigger = trigger;
            // Number of circles to draw and redraw.
            var n = 100;
            var colors = listOf(Color.Red, Color.Yellow,
                Color.Green, Color.Cyan, Color.Magenta,
                 Color.Blue, Color.White)
            var colorIndex = 0;
            for (i in 1..n) {
                colorIndex = (colorIndex + 1) % 7;
                var x = (10..900).random().toFloat( )
                var y = (10..900).random().toFloat( )
                var r = (5..100).random().toFloat( )
                // Draw filled circle with specified
                // color.
                drawCircle(
                    color = colors[colorIndex],
                    radius = r,
                    center = Offset(x = x, y = y)
                )

                // Draw circle border.
                drawCircle(
                    color = Color.Black,
                    radius = r,
                    center = Offset(x = x, y = y),
                    style = Stroke(5f)
                )
            }
        }
    }
}

@Preview(showBackground = true)
@Composable
fun MainLayoutPreview() {
    MainLayout()
}