feat(InstallOptions): make screen scrollable

app/src/main/kotlin/com/aliucord/manager/ui/screens/installopts/InstallOptionsScreen.kt

@@ -1,6 +1,8 @@
 package com.aliucord.manager.ui.screens.installopts
 
 import androidx.compose.foundation.layout.*
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
 import androidx.compose.material3.*
 import androidx.compose.runtime.*
 import androidx.compose.ui.Alignment
@@ -22,8 +24,7 @@ import com.aliucord.manager.ui.screens.installopts.components.InstallOptionsAppB
 import com.aliucord.manager.ui.screens.installopts.components.PackageNameState
 import com.aliucord.manager.ui.screens.installopts.components.options.SwitchInstallOption
 import com.aliucord.manager.ui.screens.installopts.components.options.TextInstallOption
-import com.aliucord.manager.ui.util.DiscordVersion
-import com.aliucord.manager.ui.util.thenIf
+import com.aliucord.manager.ui.util.*
 
 class InstallOptionsScreen(
     private val supportedVersion: DiscordVersion = DiscordVersion.None,
@@ -39,9 +40,10 @@ class InstallOptionsScreen(
             topBar = { InstallOptionsAppBar() },
         ) { paddingValues ->
             Column(
-                verticalArrangement = Arrangement.spacedBy(20.dp),
+                verticalArrangement = Arrangement.spacedByLastAtBottom(20.dp),
                 modifier = Modifier
                     .fillMaxSize()
+                    .verticalScroll(rememberScrollState())
                     .padding(paddingValues)
                     .padding(horizontal = 20.dp, vertical = 10.dp)
             ) {

app/src/main/kotlin/com/aliucord/manager/ui/util/ArrangementLastAtBottom.kt

@@ -0,0 +1,52 @@
+package com.aliucord.manager.ui.util
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.runtime.Immutable
+import androidx.compose.runtime.Stable
+import androidx.compose.ui.unit.*
+import kotlin.math.min
+
+/**
+ * Arranges all the elements with [spacing] except for the last element which is
+ * spaced to the very bottom of the viewable component.
+ *
+ * ref: https://stackoverflow.com/a/69196765/13964629
+ */
+@Immutable
+class ArrangementLastAtBottom(
+    override val spacing: Dp = 0.dp,
+) : Arrangement.Vertical {
+    override fun Density.arrange(
+        totalSize: Int,
+        sizes: IntArray,
+        outPositions: IntArray,
+    ) {
+        if (sizes.isEmpty()) return
+
+        val spacingPx = spacing.roundToPx()
+        var occupied = 0
+        var lastSpace = 0
+
+        sizes.forEachIndexed { index, size ->
+            if (index == sizes.lastIndex) {
+                outPositions[index] = totalSize - size
+            } else {
+                outPositions[index] = min(occupied, totalSize - size)
+            }
+
+            lastSpace = min(spacingPx, totalSize - outPositions[index] - size)
+            occupied = outPositions[index] + size + lastSpace
+        }
+
+        occupied -= lastSpace
+    }
+}
+
+/**
+ * Arranges all the elements vertically with [space] except for the last element
+ * which is drawn at the very bottom of the viewable bounds of the component.
+ */
+@Stable
+@Suppress("UnusedReceiverParameter")
+fun Arrangement.spacedByLastAtBottom(space: Dp) =
+    ArrangementLastAtBottom(space)