Display alternate symbols at different scales

/* Copyright 2025 Esri
 *
 * 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.
 *
 */

package com.esri.arcgismaps.sample.displayalternatesymbolsatdifferentscales

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Surface
import androidx.compose.runtime.Composable
import com.arcgismaps.ApiKey
import com.arcgismaps.ArcGISEnvironment
import com.esri.arcgismaps.sample.sampleslib.theme.SampleAppTheme
import com.esri.arcgismaps.sample.displayalternatesymbolsatdifferentscales.screens.DisplayAlternateSymbolsAtDifferentScalesScreen

class MainActivity : ComponentActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        // authentication with an API key or named user is
        // required to access basemaps and other location services
        ArcGISEnvironment.apiKey = ApiKey.create(BuildConfig.ACCESS_TOKEN)

        setContent {
            SampleAppTheme {
                DisplayAlternateSymbolsAtDifferentScalesApp()
            }
        }
    }

    @Composable
    private fun DisplayAlternateSymbolsAtDifferentScalesApp() {
        Surface(color = MaterialTheme.colorScheme.background) {
            DisplayAlternateSymbolsAtDifferentScalesScreen(
                sampleName = getString(R.string.display_alternate_symbols_at_different_scales_app_name)
            )
        }
    }
}

/* Copyright 2025 Esri
 *
 * 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.
 *
 */

package com.esri.arcgismaps.sample.displayalternatesymbolsatdifferentscales.components

import android.app.Application
import androidx.lifecycle.AndroidViewModel
import androidx.lifecycle.viewModelScope
import com.arcgismaps.Color
import com.arcgismaps.data.ServiceFeatureTable
import com.arcgismaps.geometry.Point
import com.arcgismaps.mapping.ArcGISMap
import com.arcgismaps.mapping.BasemapStyle
import com.arcgismaps.mapping.Viewpoint
import com.arcgismaps.mapping.layers.FeatureLayer
import com.arcgismaps.mapping.symbology.SimpleMarkerSymbol
import com.arcgismaps.mapping.symbology.SimpleMarkerSymbolStyle
import com.arcgismaps.mapping.symbology.SymbolReferenceProperties
import com.arcgismaps.mapping.symbology.UniqueValue
import com.arcgismaps.mapping.symbology.UniqueValueRenderer
import com.arcgismaps.toolkit.geoviewcompose.MapViewProxy
import com.esri.arcgismaps.sample.sampleslib.components.MessageDialogViewModel
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.asStateFlow
import kotlinx.coroutines.launch

/**
 * ViewModel for the sample demonstrating alternate symbols at different scales.
 */
class DisplayAlternateSymbolsAtDifferentScalesViewModel(app: Application) : AndroidViewModel(app) {

    // Feature layer created from the service, using URL for the SF311 incidents feature layer
    private val featureLayer = FeatureLayer.createWithFeatureTable(
        featureTable = ServiceFeatureTable(
            uri = "https://sampleserver6.arcgisonline.com/arcgis/rest/services/SF311/FeatureServer/0"
        )
    )

    // Map initialized to the a viewpoint and feature layer.
    val arcGISMap: ArcGISMap = ArcGISMap(BasemapStyle.ArcGISTopographic).apply {
        val center = Point(
            x = -13631200.0,
            y = 4546830.0,
            spatialReference = com.arcgismaps.geometry.SpatialReference.webMercator()
        )
        initialViewpoint = Viewpoint(center = center, scale = 7500.0)
        // Add the incidents feature layer
        operationalLayers += featureLayer
    }

    // MapViewProxy to perform viewpoint changes
    val mapViewProxy = MapViewProxy()

    // Expose the current MapView scale
    private val _currentScale = MutableStateFlow(arcGISMap.initialViewpoint?.targetScale)
    val currentScale = _currentScale.asStateFlow()

    // Message dialog helper for errors
    val messageDialogVM = MessageDialogViewModel()

    init {
        viewModelScope.launch {
            // Load the map with the feature layer
            arcGISMap.load().onFailure { return@launch messageDialogVM.showMessageDialog(it) }
            // Configure the unique value renderer
            configureUniqueValueRenderer()
        }
    }

    /**
     * Build the multilayer symbols with reference scale ranges and apply a [UniqueValueRenderer]
     * to the feature layer. Alternate symbols are assigned to scale ranges.
     */
    private fun configureUniqueValueRenderer() {
        // Red triangle used for the base symbol (0 - 5,000)
        val redTriangle = SimpleMarkerSymbol(
            style = SimpleMarkerSymbolStyle.Triangle,
            color = Color.red,
            size = 30f
        ).toMultilayerSymbol().apply {
            referenceProperties = SymbolReferenceProperties(
                minScale = 5_000.0,
                maxScale = 0.0
            )
        }

        // Blue square alternate symbol (5,000 - 10,000)
        val blueSquare = SimpleMarkerSymbol(
            style = SimpleMarkerSymbolStyle.Square,
            color = Color.blue,
            size = 30f
        ).toMultilayerSymbol().apply {
            referenceProperties = SymbolReferenceProperties(
                minScale = 10_000.0,
                maxScale = 5_000.0
            )
        }

        // Yellow diamond alternate symbol (10,000 - 20,000)
        val yellowDiamond = SimpleMarkerSymbol(
            style = SimpleMarkerSymbolStyle.Diamond,
            color = Color.yellow,
            size = 30f
        ).toMultilayerSymbol().apply {
            referenceProperties = SymbolReferenceProperties(
                minScale = 20_000.0,
                maxScale = 10_000.0
            )
        }

        // Unique value using the red triangle and the alternate symbols
        val uniqueValue = UniqueValue(
            description = "unique values based on request type",
            label = "unique value",
            symbol = redTriangle,
            values = listOf("Damaged Property"),
            alternateSymbols = listOf(blueSquare, yellowDiamond)
        )

        // Default purple diamond for other values
        val purpleDiamond = SimpleMarkerSymbol(
            style = SimpleMarkerSymbolStyle.Diamond,
            color = Color.fromRgba(r = 128, g = 0, b = 128),
            size = 15f
        ).toMultilayerSymbol()

        val uniqueValueRenderer = UniqueValueRenderer(
            fieldNames = listOf("req_type"),
            uniqueValues = listOf(uniqueValue),
            defaultSymbol = purpleDiamond
        )

        // Set the renderer to symbolize geo-elements with a distinct symbol.
        featureLayer.renderer = uniqueValueRenderer
    }

    /**
     * Called from the MapView composable when the viewpoint changes.
     */
    fun updateScale(newScale: Double?) {
        _currentScale.value = newScale
    }

    /**
     * Reset the viewpoint to the map's initial viewpoint using MapViewProxy.
     */
    fun resetViewpoint() {
        val initialViewpoint = arcGISMap.initialViewpoint ?: return
        viewModelScope.launch {
            mapViewProxy.setViewpointAnimated(initialViewpoint)
        }
    }
}

/* Copyright 2025 Esri
 *
 * 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.
 *
 */

package com.esri.arcgismaps.sample.displayalternatesymbolsatdifferentscales.screens

import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.padding
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.OutlinedButton
import androidx.compose.material3.Scaffold
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.dp
import androidx.lifecycle.compose.collectAsStateWithLifecycle
import androidx.lifecycle.viewmodel.compose.viewModel
import com.arcgismaps.mapping.Viewpoint
import com.arcgismaps.toolkit.geoviewcompose.MapView
import com.esri.arcgismaps.sample.displayalternatesymbolsatdifferentscales.components.DisplayAlternateSymbolsAtDifferentScalesViewModel
import com.esri.arcgismaps.sample.sampleslib.components.MessageDialog
import com.esri.arcgismaps.sample.sampleslib.components.SampleTopAppBar

/**
 * Main screen layout for the sample.
 */
@Composable
fun DisplayAlternateSymbolsAtDifferentScalesScreen(sampleName: String) {
    val mapViewModel: DisplayAlternateSymbolsAtDifferentScalesViewModel = viewModel()

    // Collect the current scale
    val currentScale by mapViewModel.currentScale.collectAsStateWithLifecycle()

    Scaffold(topBar = { SampleTopAppBar(title = sampleName) }) { padding ->
        Column(
            modifier = Modifier
                .fillMaxSize()
                .padding(padding)
        ) {
            MapView(
                modifier = Modifier
                    .fillMaxWidth()
                    .weight(1f),
                arcGISMap = mapViewModel.arcGISMap,
                mapViewProxy = mapViewModel.mapViewProxy,
                onViewpointChangedForCenterAndScale = { newViewpoint: Viewpoint? ->
                    // Update only the scale in the view model when viewpoint changes
                    mapViewModel.updateScale(newViewpoint?.targetScale)
                }
            )

            // Controls displayed below the MapView
            RendererControls(
                scale = currentScale,
                onReset = mapViewModel::resetViewpoint
            )
        }

        // Show message dialogs for errors
        mapViewModel.messageDialogVM.apply {
            if (dialogStatus) {
                MessageDialog(
                    title = messageTitle,
                    description = messageDescription,
                    onDismissRequest = ::dismissDialog
                )
            }
        }
    }
}

@Composable
private fun RendererControls(scale: Double?, onReset: () -> Unit) {
    Column(
        modifier = Modifier
            .fillMaxWidth()
            .padding(12.dp),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.spacedBy(8.dp)
    ) {
        // Display the current scale; format if available
        val scaleText = scale?.let {
            String.format(null, "Scale: 1:%,d", it.toInt())
        } ?: "Scale: N/A"

        Text(text = scaleText, style = MaterialTheme.typography.titleMedium)
        // Reset viewpoint button
        OutlinedButton(onClick = onReset) {
            Text(text = "Reset Viewpoint")
        }
    }
}