Merge pull request #20 from matejdro/screenshots

add screenshot packets

src/commonMain/kotlin/io/rebble/libpebblecommon/packets/Screenshot.kt

@@ -0,0 +1,68 @@
+package io.rebble.libpebblecommon.packets
+
+import io.rebble.libpebblecommon.protocolhelpers.PacketRegistry
+import io.rebble.libpebblecommon.protocolhelpers.PebblePacket
+import io.rebble.libpebblecommon.protocolhelpers.ProtocolEndpoint
+import io.rebble.libpebblecommon.structmapper.SUByte
+import io.rebble.libpebblecommon.structmapper.SUInt
+import io.rebble.libpebblecommon.structmapper.SUnboundBytes
+import io.rebble.libpebblecommon.structmapper.StructMappable
+
+class ScreenshotRequest : PebblePacket(ProtocolEndpoint.SCREENSHOT) {
+    /**
+     * Command. Only one command (take screenshot, value 0) is supported for now
+     */
+    val command = SUByte(m, 0u)
+}
+
+class ScreenshotResponse : PebblePacket(ProtocolEndpoint.SCREENSHOT) {
+    val data = SUnboundBytes(m)
+}
+
+class ScreenshotHeader : StructMappable() {
+    /**
+     * @see ScreenshotResponseCode
+     */
+    val responseCode = SUByte(m)
+
+    /**
+     * @see ScreenshotVersion
+     */
+    val version = SUInt(m)
+
+    val width = SUInt(m)
+    val height = SUInt(m)
+    val data = SUnboundBytes(m)
+}
+
+enum class ScreenshotResponseCode(val rawCode: UByte) {
+    OK(0u),
+    MalformedCommand(0u),
+    OutOfMemory(0u),
+    AlreadyInProgress(0u);
+
+    companion object {
+        fun fromRawCode(rawCode: UByte): ScreenshotResponseCode {
+            return values().firstOrNull { it.rawCode == rawCode }
+                ?: error("Unknown screenshot response code: $rawCode")
+        }
+    }
+}
+
+enum class ScreenshotVersion(val rawCode: UInt) {
+    BLACK_WHITE_1_BIT(1u),
+    COLOR_8_BIT(2u);
+
+    companion object {
+        fun fromRawCode(rawCode: UInt): ScreenshotVersion {
+            return values().firstOrNull { it.rawCode == rawCode }
+                ?: error("Unknown screenshots version: $rawCode")
+        }
+    }
+}
+
+fun screenshotPacketsRegister() {
+    PacketRegistry.register(ProtocolEndpoint.SCREENSHOT) {
+        ScreenshotResponse()
+    }
+}

src/commonMain/kotlin/io/rebble/libpebblecommon/protocolhelpers/PacketRegistry.kt

@@ -26,6 +26,7 @@ object PacketRegistry {
         appFetchIncomingPacketsRegister()
         putBytesIncomingPacketsRegister()
         appReorderIncomingRegister()
+        screenshotPacketsRegister()
     }
 
     /**

src/commonMain/kotlin/io/rebble/libpebblecommon/services/ScreenshotService.kt

@@ -0,0 +1,29 @@
+package io.rebble.libpebblecommon.services
+
+import io.rebble.libpebblecommon.ProtocolHandler
+import io.rebble.libpebblecommon.packets.ScreenshotRequest
+import io.rebble.libpebblecommon.packets.ScreenshotResponse
+import io.rebble.libpebblecommon.protocolhelpers.PebblePacket
+import io.rebble.libpebblecommon.protocolhelpers.ProtocolEndpoint
+import kotlinx.coroutines.channels.Channel
+
+class ScreenshotService(private val protocolHandler: ProtocolHandler) : ProtocolService {
+    val receivedMessages = Channel<ScreenshotResponse>(Channel.BUFFERED)
+
+    init {
+        protocolHandler.registerReceiveCallback(ProtocolEndpoint.SCREENSHOT, this::receive)
+    }
+
+    suspend fun send(packet: ScreenshotRequest) {
+        protocolHandler.send(packet)
+    }
+
+    fun receive(packet: PebblePacket) {
+        if (packet !is ScreenshotResponse) {
+            throw IllegalStateException("Received invalid packet type: $packet")
+        }
+
+        receivedMessages.offer(packet)
+    }
+
+}

src/commonMain/kotlin/io/rebble/libpebblecommon/structmapper/types.kt

@@ -331,6 +331,44 @@ class SBytes(
     }
 }
 
+/**
+ * Byte array without bounded size. It reads until whole packet buffer is read.
+ *
+ * This must be declared as last object
+ *
+ * Only for reading from watch.
+ */
+class SUnboundBytes(
+    mapper: StructMapper,
+    endianness: Char = '|'
+) : StructElement<UByteArray>(
+    { buf, el ->
+        throw UnsupportedOperationException("SUnboundBytes is read-only")
+    },
+    { buf, el ->
+        val leftBytes = buf.length - buf.readPosition
+        val value = buf.getBytes(leftBytes)
+        el.set(if (el.isLittleEndian) value.reversedArray() else value)
+    },
+    mapper, 0, ubyteArrayOf(), endianness
+) {
+
+    override fun toString(): String {
+        return "SUnboundBytes(value=${get().contentToString()})"
+    }
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other !is SUnboundBytes) return false
+        if (get() != other.get()) return false
+        return true
+    }
+
+    override fun hashCode(): Int {
+        return get().hashCode()
+    }
+}
+
 /**
  * Represents a fixed size list of T
  * @param T the type (must inherit Mappable)