[UNTIL-19514] Print engine epson ios support

iosApp/iosApp/Info.plist

@@ -9,5 +9,20 @@
 		<key>UIApplicationSupportsMultipleScenes</key>
 		<false/>
 	</dict>
+	<key>NSBluetoothAlwaysUsageDescription</key>
+	<string>Required to discover and connect to Epson printers via Bluetooth.</string>
+	<key>NSLocalNetworkUsageDescription</key>
+	<string>Required to discover and connect to Epson printers on the local network.</string>
+	<key>NSBonjourServices</key>
+	<array>
+		<string>_printer._tcp</string>
+		<string>_pdl-datastream._tcp</string>
+		<string>_ipp._tcp</string>
+		<string>_ipps._tcp</string>
+	</array>
+	<key>UISupportedExternalAccessoryProtocols</key>
+	<array>
+		<string>com.epson.escpos</string>
+	</array>
 </dict>
 </plist>

print-plugins/epson/src/iosMain/kotlin/de/tillhub/printengine/epson/EpsonPrinterDiscovery.ios.kt

@@ -1,10 +1,102 @@
 package de.tillhub.printengine.epson
 
+import com.epson.epos2.Epos2DeviceInfo
+import com.epson.epos2.Epos2Discovery
+import com.epson.epos2.Epos2DiscoveryDelegateProtocol
+import com.epson.epos2.Epos2FilterOption
+import de.tillhub.printengine.data.ConnectionType
 import de.tillhub.printengine.data.DiscoveryState
+import de.tillhub.printengine.data.ExternalPrinter
+import de.tillhub.printengine.data.PrinterInfo
+import de.tillhub.printengine.data.PrinterServiceVersion
+import de.tillhub.printengine.data.PrintingFontType
+import de.tillhub.printengine.data.PrintingPaperSpec
 import de.tillhub.printengine.external.PrinterDiscovery
+import kotlinx.cinterop.ExperimentalForeignApi
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.channels.awaitClose
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.callbackFlow
+import kotlinx.coroutines.withContext
+import platform.darwin.NSObject
 
+@OptIn(ExperimentalForeignApi::class)
 actual class EpsonPrinterDiscovery : PrinterDiscovery {
+
+    private companion object {
+        const val CHARACTER_COUNT = 42
+        const val MANUFACTURER_EPSON = "EPSON"
+
+        // ePOS2.h enum values
+        const val EPOS2_SUCCESS = 0
+        const val EPOS2_PORTTYPE_ALL = 0
+        const val EPOS2_TYPE_PRINTER = 1
+        const val EPOS2_MODEL_ALL = 0
+    }
+
     actual override val observePrinters: Flow<DiscoveryState>
-        get() = TODO("Not yet implemented")
+        get() = callbackFlow {
+            trySend(DiscoveryState.Idle)
+
+            val discoveredPrinters = mutableMapOf<String, ExternalPrinter>()
+
+            val filterOption = Epos2FilterOption().apply {
+                portType = EPOS2_PORTTYPE_ALL
+                deviceType = EPOS2_TYPE_PRINTER
+                deviceModel = EPOS2_MODEL_ALL
+            }
+
+            // Epson SDK dispatches onDiscovery callbacks sequentially on its internal thread
+            val discoveryDelegate = object : NSObject(), Epos2DiscoveryDelegateProtocol {
+                override fun onDiscovery(deviceInfo: Epos2DeviceInfo?) {
+                    val info = deviceInfo ?: return
+                    if (!info.isValid()) return
+                    val printer = createPrinter(info)
+                    discoveredPrinters[printer.connectionAddress] = printer
+                    trySend(DiscoveryState.Discovering(discoveredPrinters.values.toList()))
+                }
+            }
+
+            val result = withContext(Dispatchers.Main) {
+                Epos2Discovery.start(filterOption, discoveryDelegate)
+            }
+            if (result != EPOS2_SUCCESS) {
+                trySend(DiscoveryState.Error("Discovery start failed with code: $result"))
+            }
+
+            awaitClose {
+                Epos2Discovery.stop()
+                // Reference delegate to prevent Kotlin/Native GC from collecting it
+                // while the Epson SDK still holds a weak reference to it
+                discoveryDelegate.hashCode()
+            }
+        }
+
+    private fun createPrinter(deviceInfo: Epos2DeviceInfo): ExternalPrinter {
+        val target = deviceInfo.target ?: ""
+        val dividerIdx = target.indexOf(':')
+        val protocol = if (dividerIdx >= 0) target.substring(0, dividerIdx) else ""
+        val address = if (dividerIdx >= 0) target.substring(dividerIdx + 1) else target
+
+        return ExternalPrinter(
+            info = PrinterInfo(
+                serialNumber = "n/a",
+                deviceModel = deviceInfo.deviceName ?: "",
+                printerVersion = "n/a",
+                printerPaperSpec = PrintingPaperSpec.External(CHARACTER_COUNT),
+                printingFontType = PrintingFontType.DEFAULT_FONT_SIZE,
+                printerHead = "n/a",
+                printedDistance = 0,
+                serviceVersion = PrinterServiceVersion.Unknown,
+            ),
+            manufacturer = MANUFACTURER_EPSON,
+            connectionAddress = address,
+            connectionType = protocol.toConnectionType(),
+        )
+    }
+
+    private fun String.toConnectionType(): ConnectionType = ConnectionType.entries.find { it.value == this }
+        ?: ConnectionType.LAN
+
+    private fun Epos2DeviceInfo.isValid(): Boolean = deviceType == EPOS2_TYPE_PRINTER && !deviceName.isNullOrEmpty()
 }

sample/src/commonMain/kotlin/de/tillhub/printengine/sample/ui/PrinterLayout.kt

@@ -30,6 +30,7 @@ fun PrinterLayout(
     printState: PrinterState,
     printers: List<ExternalPrinter>,
     onPrinterSelected: (ExternalPrinter?) -> Unit,
+    discoveryStatus: String? = null,
 ) {
     Column(
         modifier = Modifier.fillMaxSize(),
@@ -41,6 +42,14 @@ fun PrinterLayout(
             textAlign = TextAlign.Center,
             style = MaterialTheme.typography.bodyLarge,
         )
+        if (discoveryStatus != null) {
+            Spacer(modifier = Modifier.height(8.dp))
+            Text(
+                text = discoveryStatus,
+                textAlign = TextAlign.Center,
+                style = MaterialTheme.typography.bodySmall,
+            )
+        }
         Spacer(modifier = Modifier.height(36.dp))
         Button(onClick = { onPrinterSelected(null) }) {
             Text(text = "Print sample job")

sample/src/iosMain/kotlin/de/tillhub/printengine/sample/MainViewController.kt

@@ -3,6 +3,7 @@ package de.tillhub.printengine.sample
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateListOf
@@ -13,11 +14,13 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.window.ComposeUIViewController
 import de.tillhub.printengine.PrintEngine
+import de.tillhub.printengine.data.DiscoveryState
 import de.tillhub.printengine.data.ExternalPrinter
 import de.tillhub.printengine.data.PrintCommand
 import de.tillhub.printengine.data.PrintJob
 import de.tillhub.printengine.data.PrinterState
 import de.tillhub.printengine.data.PrintingIntensity
+import de.tillhub.printengine.epson.EpsonPrinterDiscovery
 import de.tillhub.printengine.epson.EpsonServiceProvider
 import de.tillhub.printengine.sample.ui.PrinterLayout
 import de.tillhub.printengine.sample.ui.theme.TillhubPrintEngineTheme
@@ -34,8 +37,32 @@ fun MainViewController(): UIViewController = ComposeUIViewController {
 
     val printers = remember { mutableStateListOf<ExternalPrinter>() }
     var initialized by remember { mutableStateOf(false) }
+    var discoveryStatus by remember { mutableStateOf("Searching for printers…") }
     val scope = rememberCoroutineScope()
 
+    LaunchedEffect(Unit) {
+        printEngine.discoverExternalPrinters(
+            EpsonPrinterDiscovery(),
+        ).collect { state ->
+            when (state) {
+                is DiscoveryState.Idle -> discoveryStatus = "Searching for printers…"
+                is DiscoveryState.Discovering -> {
+                    printers.clear()
+                    printers.addAll(state.printers)
+                    discoveryStatus = "Found ${state.printers.size} printer(s)"
+                }
+                is DiscoveryState.Finished -> {
+                    printers.clear()
+                    printers.addAll(state.printers)
+                    discoveryStatus = "Discovery done: ${state.printers.size} printer(s)"
+                }
+                is DiscoveryState.Error -> {
+                    discoveryStatus = "Discovery error: ${state.message}"
+                }
+            }
+        }
+    }
+
     val printState by printEngine.printer.printerState
         .collectAsState(PrinterState.CheckingForPrinter)
 
@@ -46,6 +73,7 @@ fun MainViewController(): UIViewController = ComposeUIViewController {
         ) {
             PrinterLayout(
                 printState = printState,
+                discoveryStatus = discoveryStatus,
                 printers = printers,
                 onPrinterSelected = { selectedPrinter ->
                     scope.launch {
@@ -56,6 +84,7 @@ fun MainViewController(): UIViewController = ComposeUIViewController {
                                 }
                                 initialized = true
                             } catch (_: Exception) {
+                                discoveryStatus = "Failed to initialize printer"
                                 return@launch
                             }
                         }