ThemeSwitch

ThemeSwitch.kt

/*
 * Copyright 2025 Kyriakos Georgiopoulos
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import androidx.compose.animation.animateColorAsState
import androidx.compose.animation.core.animateDpAsState
import androidx.compose.animation.core.animateFloatAsState
import androidx.compose.animation.core.tween
import androidx.compose.foundation.Canvas
import androidx.compose.foundation.Image
import androidx.compose.foundation.background
import androidx.compose.foundation.border
import androidx.compose.foundation.clickable
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.offset
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.runtime.Composable
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.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.draw.rotate
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.graphics.Brush
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.res.painterResource
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import com.zengrip.R

@Composable
fun ThemeSwitch(
    isDarkTheme: Boolean,
    onCheckedChange: (Boolean) -> Unit,
) {
    // Animate circle’s movement smoothly
    val offset by animateDpAsState(
        targetValue = if (isDarkTheme) 96.dp else 4.dp,
        animationSpec = tween(durationMillis = 500)
    )

    // Animate icon rotation (0 for day, 360 for night)
    val rotation by animateFloatAsState(
        targetValue = if (isDarkTheme) 360f else 0f,
        animationSpec = tween(durationMillis = 500)
    )

    // Animate background color for sunset/sunrise
    val backgroundStart by animateColorAsState(
        targetValue = if (isDarkTheme) Color(0xFF000022) else Color(0xFFFFE082),
        animationSpec = tween(durationMillis = 1000)
    )

    val backgroundEnd by animateColorAsState(
        targetValue = if (isDarkTheme) Color(0xFF000033) else Color(0xFFFFC107),
        animationSpec = tween(durationMillis = 1000)
    )

    Box(
        modifier = Modifier
            .size(width = 160.dp, height = 70.dp)
            .clip(RoundedCornerShape(40.dp))
            .border(
                width = 4.dp,
                color = if (isDarkTheme) {
                    Color.White.copy(alpha = 0.5f)
                } else {
                    Color(0xFFFFA500).copy(alpha = 0.4f)
                },
                shape = RoundedCornerShape(40.dp)
            )
            .clickable { onCheckedChange(!isDarkTheme) }
            .background( // Apply gradient directly
                Brush.linearGradient(
                    colors = listOf(backgroundStart, backgroundEnd)
                )
            ),
        contentAlignment = Alignment.CenterStart
    ) {
        // If it's dark, draw some "stars"
        if (isDarkTheme) {
            val numberOfStars = 30
            val stars = remember {
                List(numberOfStars) {
                    Star(
                        x = (0..100).random().toFloat(),
                        y = (0..100).random().toFloat(),
                        radius = (1..3).random().toFloat()
                    )
                }
            }

            Canvas(
                modifier = Modifier
                    .fillMaxSize()
                    .padding(10.dp)
            ) {
                val padding = 10f
                val width = size.width - padding * 2
                val height = size.height - padding * 2

                for (star in stars) {
                    drawCircle(
                        color = Color.White.copy(alpha = 0.8f),
                        center = Offset(
                            padding + star.x / 100 * width,
                            padding + star.y / 100 * height
                        ),
                        radius = star.radius
                    )
                }
            }
        }

        Box(
            modifier = Modifier
                .offset(x = offset)
                .size(60.dp)
                .clip(CircleShape)
                .background(Color.White)
                .padding(6.dp),
            contentAlignment = Alignment.Center
        ) {
            Image(
                painter = painterResource(id = if (isDarkTheme) R.drawable.moon else R.drawable.sun),
                contentDescription = if (isDarkTheme) "Switch to Light" else "Switch to Dark",
                modifier = Modifier.size(40.dp)
                    .rotate(rotation)
            )
        }
    }
}

@Preview
@Composable
fun EnhancedThemeSwitchPreview() {
    var isDark by remember { mutableStateOf(false) }

    Box(
        modifier = Modifier
            .fillMaxSize()
            .background(Color(0xFF303030)),
        contentAlignment = Alignment.Center
    ) {
        ThemeSwitch(isDark) { isDark = it }
    }
}


data class Star(val x: Float, val y: Float, val radius: Float)