wear/watchface/watchface/src/main/java/androidx/wear/watchface/control/InteractiveInstanceManager.kt

/*
 * Copyright 2020 The Android Open Source Project
 *
 * 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 androidx.wear.watchface.control

import android.os.Build
import android.util.Log
import androidx.annotation.UiThread
import androidx.annotation.VisibleForTesting
import androidx.wear.watchface.IndentingPrintWriter
import androidx.wear.watchface.WatchFaceService
import androidx.wear.watchface.control.data.WallpaperInteractiveWatchFaceInstanceParams
import androidx.wear.watchface.utility.TraceEvent

/** Keeps track of [InteractiveWatchFaceImpl]s. */
internal class InteractiveInstanceManager {
    private constructor()

    private class RefCountedInteractiveWatchFaceInstance(
        val impl: InteractiveWatchFaceImpl,
        var refcount: Int
    ) {
        @UiThread
        fun dump(writer: IndentingPrintWriter) {
            writer.println("InteractiveInstanceManager:")
            writer.increaseIndent()
            writer.println("impl.instanceId=${impl.instanceId}")
            writer.println("refcount=$refcount")
            impl.engine?.dump(writer)
            writer.decreaseIndent()
        }
    }

    class PendingWallpaperInteractiveWatchFaceInstance(
        val params: WallpaperInteractiveWatchFaceInstanceParams,
        val callback: IPendingInteractiveWatchFace
    )

    companion object {
        private const val TAG = "InteractiveInstanceManager"

        private val instances = HashMap<String, RefCountedInteractiveWatchFaceInstance>()
        private val pendingWallpaperInteractiveWatchFaceInstanceLock = Any()
        private var pendingWallpaperInteractiveWatchFaceInstance:
            PendingWallpaperInteractiveWatchFaceInstance? =
            null
        private var parameterlessEngine: WatchFaceService.EngineWrapper? = null

        @VisibleForTesting
        fun getInstances() =
            synchronized(pendingWallpaperInteractiveWatchFaceInstanceLock) {
                instances.map { it.key }
            }

        fun addInstance(impl: InteractiveWatchFaceImpl) {
            synchronized(pendingWallpaperInteractiveWatchFaceInstanceLock) {
                require(!instances.containsKey(impl.instanceId)) {
                    "Already have an InteractiveWatchFaceImpl with id ${impl.instanceId}"
                }
                instances[impl.instanceId] = RefCountedInteractiveWatchFaceInstance(impl, 1)
            }
        }

        /**
         * We either return the pendingWallpaperInteractiveWatchFaceInstance if there is one or set
         * parameterlessEngine. A parameterless engine, is one that's been created without any start
         * up params. Typically this can only happen if a WSL watchface is upgraded to an androidx
         * one, so WallpaperManager knows about it but WearServices/WSL does not.
         */
        fun setParameterlessEngineOrTakePendingWallpaperInteractiveWatchFaceInstance(
            parameterlessEngine: WatchFaceService.EngineWrapper?
        ): PendingWallpaperInteractiveWatchFaceInstance? {
            synchronized(pendingWallpaperInteractiveWatchFaceInstanceLock) {
                require(this.parameterlessEngine == null || parameterlessEngine == null) {
                    "Already have a parameterlessEngine registered"
                }

                if (pendingWallpaperInteractiveWatchFaceInstance == null) {
                    this.parameterlessEngine = parameterlessEngine
                    return null
                } else {
                    val returnValue = pendingWallpaperInteractiveWatchFaceInstance
                    pendingWallpaperInteractiveWatchFaceInstance = null
                    return returnValue
                }
            }
        }

        /**
         * A parameterless engine, is one that's been created without any start up params. Typically
         * this can only happen if a WSL watchface is upgraded to an androidx one, so
         * WallpaperManager knows about it but WearServices/WSL does not.
         */
        fun setParameterlessEngine(parameterlessEngine: WatchFaceService.EngineWrapper?) {
            synchronized(pendingWallpaperInteractiveWatchFaceInstanceLock) {
                require(this.parameterlessEngine == null || parameterlessEngine == null) {
                    "Already have a parameterlessEngine registered"
                }
                this.parameterlessEngine = parameterlessEngine
            }
        }

        fun getParameterlessEngine(): WatchFaceService.EngineWrapper? {
            synchronized(pendingWallpaperInteractiveWatchFaceInstanceLock) {
                return parameterlessEngine
            }
        }

        fun getAndRetainInstance(instanceId: String): InteractiveWatchFaceImpl? {
            synchronized(pendingWallpaperInteractiveWatchFaceInstanceLock) {
                val refCountedInstance = instances[instanceId] ?: return null
                refCountedInstance.refcount++
                return refCountedInstance.impl
            }
        }

        fun releaseInstance(instanceId: String) {
            synchronized(pendingWallpaperInteractiveWatchFaceInstanceLock) {
                instances[instanceId]?.let {
                    if (--it.refcount == 0) {
                        it.impl.onDestroy()
                        instances.remove(instanceId)
                    }
                }
            }
        }

        fun deleteInstance(instanceId: String) {
            synchronized(pendingWallpaperInteractiveWatchFaceInstanceLock) {
                instances[instanceId]?.impl?.onDestroy()
                instances.remove(instanceId)
            }
        }

        fun renameInstance(oldInstanceId: String, newInstanceId: String) {
            synchronized(pendingWallpaperInteractiveWatchFaceInstanceLock) {
                val instance = instances.remove(oldInstanceId)
                require(instance != null) {
                    "Expected an InteractiveWatchFaceImpl with id $oldInstanceId"
                }
                require(!instances.containsKey(newInstanceId)) {
                    "Already have an InteractiveWatchFaceImpl with id $newInstanceId"
                }
                instances.put(newInstanceId, instance)
            }
        }

        fun getCurrentInteractiveInstance(): InteractiveWatchFaceImpl? {
            synchronized(pendingWallpaperInteractiveWatchFaceInstanceLock) {
                if (instances.size == 1) {
                    return instances.entries.first().value.impl
                }
            }
            return null
        }

        /** Can be called on any thread. */
        fun getExistingInstanceOrSetPendingWallpaperInteractiveWatchFaceInstance(
            value: PendingWallpaperInteractiveWatchFaceInstance
        ): IInteractiveWatchFace? {
            val impl =
                synchronized(pendingWallpaperInteractiveWatchFaceInstanceLock) {
                    val instance = instances[value.params.instanceId]

                    if (instance == null) {
                        parameterlessEngine?.let {
                            parameterlessEngine = null
                            it.attachToParameterlessEngine(value)
                            return null
                        }

                        TraceEvent("Set pendingWallpaperInteractiveWatchFaceInstance").use {
                            pendingWallpaperInteractiveWatchFaceInstance = value
                        }
                        return null
                    }
                    if (instance.impl.engine == parameterlessEngine) {
                        parameterlessEngine = null
                    }
                    instance.impl
                }

            // The system on reboot will use this to connect to an existing watch face, we need to
            // ensure there isn't a skew between the style the watch face actually has and what the
            // system thinks we should have. Note runBlocking is safe here because we never await.
            val engine = impl.engine!!
            engine.setUserStyle(value.params.userStyle)

            // Note prior to android U, auxiliaryComponentPackageName may be non null for regular
            // watch faces.
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE &&
                engine.resourceOnlyWatchFacePackageName !=
                    value.params.auxiliaryComponentPackageName
            ) {
                val message =
                    "Existing instance has the resourceOnlyWatchFacePackageName of " +
                        "${engine.resourceOnlyWatchFacePackageName}, which is different from the " +
                        "argument watchFaceId of ${value.params.auxiliaryComponentPackageName}."
                Log.e(TAG, message)
                throw IllegalStateException(message)
            }

            return impl
        }

        /** Can be called on any thread. */
        fun takePendingWallpaperInteractiveWatchFaceInstance():
            PendingWallpaperInteractiveWatchFaceInstance? {
            synchronized(pendingWallpaperInteractiveWatchFaceInstanceLock) {
                val returnValue = pendingWallpaperInteractiveWatchFaceInstance
                pendingWallpaperInteractiveWatchFaceInstance = null
                return returnValue
            }
        }

        @UiThread
        fun dump(writer: IndentingPrintWriter) {
            writer.println("InteractiveInstanceManager instances:")
            writer.increaseIndent()
            pendingWallpaperInteractiveWatchFaceInstance?.let {
                writer.println(
                    "Pending WallpaperInteractiveWatchFaceInstance id ${it.params.instanceId}"
                )
            }
            synchronized(pendingWallpaperInteractiveWatchFaceInstanceLock) {
                for ((_, value) in instances) {
                    value.dump(writer)
                }
            }
            writer.decreaseIndent()
        }
    }
}