feat(bar): support per-bar color palettes in playground

playground/src/jsMain/kotlin/codegen/bar/BarStyleProperties.kt

@@ -6,11 +6,19 @@ import model.BarStyleState
 import model.StylePropertiesSnapshot
 
 @Composable
-fun barStylePropertiesSnapshot(styleState: BarStyleState): StylePropertiesSnapshot {
+fun barStylePropertiesSnapshot(
+    styleState: BarStyleState,
+    seriesCount: Int,
+): StylePropertiesSnapshot {
     val defaultStyle = BarChartDefaults.style()
+    val normalizedBarColors =
+        styleState.barColors?.let { colors ->
+            normalizeColorCount(colors = colors, targetCount = seriesCount)
+        }
     val currentStyle =
         BarChartDefaults.style(
             barColor = styleState.barColor ?: defaultStyle.barColor,
+            barColors = normalizedBarColors ?: defaultStyle.barColors,
             barAlpha = styleState.barAlpha ?: defaultStyle.barAlpha,
             gridVisible = styleState.gridVisible ?: defaultStyle.gridVisible,
             axisVisible = styleState.axisVisible ?: defaultStyle.axisVisible,
@@ -23,3 +31,11 @@ fun barStylePropertiesSnapshot(styleState: BarStyleState): StylePropertiesSnapsh
         defaults = defaultStyle.getProperties(),
     )
 }
+
+private fun normalizeColorCount(
+    colors: List<androidx.compose.ui.graphics.Color>,
+    targetCount: Int,
+): List<androidx.compose.ui.graphics.Color> {
+    if (targetCount <= 0 || colors.isEmpty()) return emptyList()
+    return List(targetCount) { index -> colors[index % colors.size] }
+}

playground/src/jsMain/kotlin/model/PlaygroundModels.kt

@@ -58,6 +58,7 @@ data class MultiLineStyleState(
 
 data class BarStyleState(
     val barColor: Color? = null,
+    val barColors: List<Color>? = null,
     val barAlpha: Float? = null,
     val gridVisible: Boolean? = null,
     val axisVisible: Boolean? = null,

playground/src/jsMain/kotlin/model/definitions/BarChartDefinition.kt

@@ -85,6 +85,16 @@ internal object BarChartDefinition : PlaygroundChartDefinition {
                 read = { style -> (style as BarStyleState).barColor },
                 write = { style, value -> (style as BarStyleState).copy(barColor = value) },
             ),
+            SettingDescriptor.ColorPalette(
+                id = "barColors",
+                title = "Bar Colors",
+                itemCount = {
+                    val data = it.appliedData as PlaygroundDataModel.SimpleSeries
+                    data.values.size
+                },
+                read = { style -> (style as BarStyleState).barColors },
+                write = { style, value -> (style as BarStyleState).copy(barColors = value) },
+            ),
             SettingDescriptor.Divider,
             SettingDescriptor.Section("Visibility"),
             SettingDescriptor.Toggle(
@@ -140,9 +150,14 @@ internal object BarChartDefinition : PlaygroundChartDefinition {
                 labels = data.labels,
             )
         val defaultStyle = BarChartDefaults.style()
+        val normalizedBarColors =
+            styleState.barColors?.let { colors ->
+                normalizeColorCount(colors = colors, targetCount = data.values.size)
+            }
         val style =
             BarChartDefaults.style(
                 barColor = styleState.barColor ?: defaultStyle.barColor,
+                barColors = normalizedBarColors ?: defaultStyle.barColors,
                 barAlpha = styleState.barAlpha ?: defaultStyle.barAlpha,
                 gridVisible = styleState.gridVisible ?: defaultStyle.gridVisible,
                 axisVisible = styleState.axisVisible ?: defaultStyle.axisVisible,
@@ -170,7 +185,7 @@ internal object BarChartDefinition : PlaygroundChartDefinition {
                 points = points,
                 title = session.title,
                 style = style,
-                styleProperties = barStylePropertiesSnapshot(style),
+                styleProperties = barStylePropertiesSnapshot(style, data.values.size),
                 codegenMode = session.codegenMode,
                 functionName = deriveFunctionName(session.title, type),
             ),

playground/src/jsTest/kotlin/codegen/bar/BarChartCodeGeneratorTest.kt

@@ -1,5 +1,6 @@
 package codegen.bar
 
+import androidx.compose.ui.graphics.Color
 import model.BarCodegenConfig
 import model.CodegenMode
 import model.PieSliceInput
@@ -75,4 +76,27 @@ class BarChartCodeGeneratorTest {
         assertTrue(snippet.code.contains("axisVisible = true,"))
         assertTrue(snippet.code.contains("selectionLineWidth = 1.5f,"))
     }
+
+    @Test
+    fun style_with_bar_colors_emits_palette_and_color_import() {
+        val snippet =
+            generator.generate(
+                BarCodegenConfig(
+                    points =
+                        listOf(
+                            PieSliceInput(label = "A", valueText = "1"),
+                            PieSliceInput(label = "B", valueText = "2"),
+                        ),
+                    styleProperties =
+                        StylePropertiesSnapshot(
+                            current = listOf("barColors" to listOf(Color.Red, Color.Green)),
+                            defaults = listOf("barColors" to emptyList<Color>()),
+                        ),
+                    codegenMode = CodegenMode.MINIMAL,
+                ),
+            )
+
+        assertTrue(snippet.code.contains("import androidx.compose.ui.graphics.Color"))
+        assertTrue(snippet.code.contains("barColors = listOf(Color("))
+    }
 }

playground/src/jvmTest/kotlin/codegen/GeneratedSnippetCompilationTest.kt

@@ -1,5 +1,6 @@
 package codegen
 
+import androidx.compose.ui.graphics.Color
 import codegen.area.AreaChartCodeGenerator
 import codegen.bar.BarChartCodeGenerator
 import codegen.line.LineChartCodeGenerator
@@ -17,6 +18,7 @@ import model.PieCodegenConfig
 import model.PieSliceInput
 import model.RadarCodegenConfig
 import model.StackedBarCodegenConfig
+import model.StylePropertiesSnapshot
 import org.jetbrains.kotlin.cli.common.ExitCode
 import org.jetbrains.kotlin.cli.jvm.K2JVMCompiler
 import java.io.ByteArrayOutputStream
@@ -59,6 +61,17 @@ class GeneratedSnippetCompilationTest {
                                     PieSliceInput(label = "Mon", valueText = "12"),
                                     PieSliceInput(label = "Tue", valueText = "18"),
                                 ),
+                            styleProperties =
+                                StylePropertiesSnapshot(
+                                    current =
+                                        listOf(
+                                            "barColors" to listOf(Color.Red, Color.Green),
+                                        ),
+                                    defaults =
+                                        listOf(
+                                            "barColors" to emptyList<Color>(),
+                                        ),
+                                ),
                         ),
                     ).code,
                 MultiLineChartCodeGenerator()