Button.kt

import androidx.compose.foundation.BorderStroke
import androidx.compose.foundation.background
import androidx.compose.foundation.clickable
import androidx.compose.foundation.interaction.FocusInteraction
import androidx.compose.foundation.interaction.HoverInteraction
import androidx.compose.foundation.interaction.Interaction
import androidx.compose.foundation.interaction.MutableInteractionSource
import androidx.compose.foundation.interaction.PressInteraction
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.PaddingValues
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.RowScope
import androidx.compose.foundation.layout.defaultMinSize
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.shape.CornerSize
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.runtime.Composable
import androidx.compose.runtime.LaunchedEffect
import androidx.compose.runtime.mutableStateListOf
import androidx.compose.runtime.remember
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.Shape
import androidx.compose.ui.platform.LocalWindowInfo
import androidx.compose.ui.semantics.Role
import androidx.compose.ui.unit.dp


@Composable
fun Button(
    onClick: () -> Unit,
    modifier: Modifier = Modifier,
    enabled: Boolean = true,
    active: Boolean = false,
    interactionSource: MutableInteractionSource = remember { MutableInteractionSource() },
    shape: Shape = DefaultShape,
    // TODO: introduce a Appearance class
    backgroundColor: Color = Color.White,
    border: BorderStroke? = DefaultBorder,
    contentPadding: PaddingValues = DefaultContentPadding,
    content: @Composable RowScope.() -> Unit
) {
    val interactions = remember { mutableStateListOf<Interaction>() }
    LaunchedEffect(interactionSource) {
        interactionSource.interactions.collect { interaction ->
            when (interaction) {
                is HoverInteraction.Enter -> {
                    interactions.add(interaction)
                }
                is HoverInteraction.Exit -> {
                    interactions.remove(interaction.enter)
                }
                is FocusInteraction.Focus -> {
                    interactions.add(interaction)
                }
                is FocusInteraction.Unfocus -> {
                    interactions.remove(interaction.focus)
                }
                is PressInteraction.Press -> {
                    interactions.add(interaction)
                }
                is PressInteraction.Release -> {
                    interactions.remove(interaction.press)
                }
                is PressInteraction.Cancel -> {
                    interactions.remove(interaction.press)
                }
            }
        }
    }
    val interaction = interactions.lastOrNull()
    val isFocused = interaction.isFocus && LocalWindowInfo.current.isWindowFocused

    val backgroundModifier = when {
        enabled && (active || interaction.isPress) -> {
            Modifier.background(Color(0xFFD6D6D6), shape)
        }
        interaction.isHover -> Modifier.background(Color(0xFFE4E4E4), shape)
        else -> Modifier.background(backgroundColor, shape)
    }

    Box(
        modifier
            .clickable(
                onClick = onClick,
                enabled = enabled,
                role = Role.Button,
                interactionSource = interactionSource,
                indication = null
            )
            .then(backgroundModifier),
        propagateMinConstraints = true
    ) {
        Row(
            Modifier
                .defaultMinSize(8.dp, 8.dp)
                .padding(contentPadding),
            horizontalArrangement = Arrangement.Center,
            verticalAlignment = Alignment.CenterVertically,
            content = content
        )
    }
}

val Interaction?.isFocus: Boolean
    get() = this is FocusInteraction.Focus

val Interaction?.isHover: Boolean
    get() = this is HoverInteraction.Enter

val Interaction?.isPress: Boolean
    get() = this is PressInteraction.Press

private val DefaultBorder = BorderStroke(1.dp, Color(0xFFD1D1D1))
private val DefaultShape = RoundedCornerShape(CornerSize(4.dp))
private val DefaultContentPadding = PaddingValues(8.dp, 6.dp)
private val DefaultIconContentPadding = PaddingValues(2.dp)