تنفيذ مكوّنات A2UI مخصّصة

// Define static properties, dynamic bindings, and component references
val textProp = A2uiProperty.dynamicString("text", required = true)
val variantProp = A2uiProperty.stringEnum("variant", enumValues = listOf("body", "title"))
val childProp = A2uiProperty.componentId("child", required = true)
val actionProp = A2uiProperty.action("action", required = true)

object CustomTextComponent : A2uiComponent {
    private val textProp = A2uiProperty.dynamicString("text", required = true)
    private val variantProp = A2uiProperty.stringEnum(
        "variant",
        enumValues = listOf("body", "title"),
    )

    override val name = "Text"
    override val description = "Displays dynamic text."
    override val properties = listOf(textProp, variantProp)

    @Composable
    override fun A2uiComponentScope.isReady(properties: A2uiComponentProperties): Boolean {
        // The component does not become ready until dynamic text data arrives
        return properties.bind(textProp) != null
    }

    @Composable
    override fun A2uiComponentScope.Content(
        properties: A2uiComponentProperties,
        modifier: Modifier,
    ) {
        // Reactively resolve dynamic data binding and subscribe to updates
        val text = properties.bind(textProp) ?: ""

        // Read the static configuration property
        val variant = properties[variantProp] ?: "body"
        val textStyle = if (variant == "title") {
            MaterialTheme.typography.titleLarge
        } else {
            MaterialTheme.typography.bodyLarge
        }

        Text(
            text = text,
            style = textStyle,
            modifier = modifier,
        )
    }
}

val labelProp = A2uiProperty.dynamicString("label", required = true)
val valueProp = A2uiProperty.dynamicBoolean("value")

@Composable
fun A2uiComponentScope.CustomCheckbox(properties: A2uiComponentProperties) {
    // Read a dynamic property from the data model subscribing to updates
    val label = properties.bind(labelProp) ?: ""

    // Bind a property value and its updater to handle two-way data binding
    val checked = properties.bind(valueProp) ?: false
    val onCheckedChange = properties.bindUpdater(valueProp)

    Row(verticalAlignment = Alignment.CenterVertically) {
        Checkbox(
            checked = checked,
            onCheckedChange = onCheckedChange,
            enabled = (onCheckedChange != null), // Read-only if no writable path was bound
        )
        Text(text = label)
    }
}

object CustomButtonComponent : A2uiComponent {
    private val childProp = A2uiProperty.componentId("child", required = true)
    private val actionProp = A2uiProperty.action("action", required = true)

    override val name = "Button"
    override val description = "A clickable button."
    override val properties = listOf(childProp, actionProp)

    @Composable
    override fun A2uiComponentScope.Content(
        properties: A2uiComponentProperties,
        modifier: Modifier,
    ) {
        val actionDefinition = properties[actionProp]
        val childId = properties[childProp] ?: return
        val currentAction by rememberUpdatedState(actionDefinition)
        val onClick: () -> Unit = remember {
            { currentAction?.let { dispatchAction(it) } }
        }

        Button(onClick = onClick, modifier = modifier) {
            val childState = observeA2uiComponentState(id = childId)
            when (childState) {
                is A2uiComponentState.Loading -> CircularProgressIndicator()
                is A2uiComponentState.Error -> Text("Error")
                is A2uiComponentState.Success -> A2uiComponent(childState.component)
            }
        }
    }
}

val headerChildProp = A2uiProperty.componentId("headerId", required = true)

@Composable
fun A2uiComponentScope.CustomCompositeContent(
    properties: A2uiComponentProperties,
) {
    val headerId = properties[headerChildProp] ?: return

    val headerState = observeA2uiComponentState(id = headerId)
    when (headerState) {
        is A2uiComponentState.Loading -> {
            // Render a localized loading placeholder
            LinearProgressIndicator()
        }
        is A2uiComponentState.Error -> {
            // Render a localized error fallback
            Text("Failed to load header")
        }
        is A2uiComponentState.Success -> {
            // Forward the resolved child component to the visual UI router
            A2uiComponent(headerState.component)
        }
    }
}

val childrenProp = A2uiProperty.childList("children", required = true)

@Composable
fun A2uiComponentScope.CustomColumn(
    properties: A2uiComponentProperties,
    modifier: Modifier = Modifier,
) {
    // Resolve child references (supports both static ID arrays and dynamic data templates)
    val childReferences = properties.bindChildReferences(childrenProp) ?: return

    Column(modifier = modifier) {
        childReferences.forEach { reference ->
            key(reference.id, reference.baseDataPath) {
                val childState = observeA2uiComponentState(reference)
                when (childState) {
                    is A2uiComponentState.Loading -> CircularProgressIndicator()
                    is A2uiComponentState.Error -> Text("Failed to load child")
                    is A2uiComponentState.Success -> A2uiComponent(childState.component)
                }
            }
        }
    }
}

// Configure an Image component for the Basic Catalog using Coil
val coilImage = MaterialA2uiBasicCatalogV1Defaults.image { url, desc, scale, modifier, onError ->
    AsyncImage(
        model = url,
        contentDescription = desc,
        contentScale = scale,
        modifier = modifier,
        onError = { state -> onError(state.result.throwable) },
    )
}