Hello, mpv! 🎉

Model/Player/Backends/MPVBackend.swift

@@ -0,0 +1,305 @@
+import AVFAudio
+import CoreMedia
+import Foundation
+import Logging
+import SwiftUI
+
+final class MPVBackend: PlayerBackend {
+    private var logger = Logger(label: "mpv-backend")
+
+    var model: PlayerModel!
+    var controls: PlayerControlsModel!
+
+    var stream: Stream?
+    var video: Video?
+    var currentTime: CMTime?
+
+    var loadedVideo = false
+    var isLoadingVideo = true
+
+    var isPlaying = true { didSet {
+        if isPlaying {
+            startClientUpdates()
+        } else {
+            stopControlsUpdates()
+        }
+
+        updateControlsIsPlaying()
+    }}
+    var playerItemDuration: CMTime?
+
+    var controller: MPVViewController!
+    var client: MPVClient! { didSet { client.backend = self } }
+
+    private var clientTimer: RepeatingTimer!
+
+    private var onFileLoaded: (() -> Void)?
+
+    private var controlsUpdates = false
+    private var timeObserverThrottle = Throttle(interval: 2)
+
+    init(model: PlayerModel, controls: PlayerControlsModel? = nil) {
+        self.model = model
+        self.controls = controls
+
+        clientTimer = .init(timeInterval: 1)
+        clientTimer.eventHandler = getClientUpdates
+    }
+
+    func bestPlayable(_ streams: [Stream]) -> Stream? {
+        streams.filter { $0.kind == .adaptive }.max { $0.resolution < $1.resolution } ??
+            streams.first { $0.kind == .hls } ??
+            streams.first
+    }
+
+    func canPlay(_ stream: Stream) -> Bool {
+        stream.resolution != .unknown && stream.format != "AV1"
+    }
+
+    func playStream(_ stream: Stream, of video: Video, preservingTime: Bool, upgrading _: Bool) {
+        let updateCurrentStream = {
+            DispatchQueue.main.async { [weak self] in
+                self?.stream = stream
+                self?.video = video
+                self?.model.stream = stream
+            }
+        }
+
+        let startPlaying = {
+            #if !os(macOS)
+                try? AVAudioSession.sharedInstance().setActive(true)
+            #endif
+
+            DispatchQueue.main.async { [weak self] in
+                guard let self = self else {
+                    return
+                }
+
+                self.startClientUpdates()
+
+                if !preservingTime,
+                   let segment = self.model.sponsorBlock.segments.first,
+                   segment.start < 3,
+                   self.model.lastSkipped.isNil
+                {
+                    self.seek(to: segment.endTime) { finished in
+                        guard finished else {
+                            return
+                        }
+
+                        self.model.lastSkipped = segment
+                        self.play()
+                    }
+                } else {
+                    self.play()
+                }
+            }
+        }
+
+        let replaceItem: (CMTime?) -> Void = { [weak self] time in
+            guard let self = self else {
+                return
+            }
+
+            self.stop()
+
+            if let url = stream.singleAssetURL {
+                self.onFileLoaded = { [weak self] in
+                    self?.setIsLoadingVideo(false)
+                    updateCurrentStream()
+                    startPlaying()
+                }
+
+                self.client.loadFile(url, time: time) { [weak self] _ in
+                    self?.setIsLoadingVideo(true)
+                }
+            } else {
+                self.onFileLoaded = { [weak self] in
+                    self?.client.addAudio(stream.audioAsset.url) { _ in
+                        self?.setIsLoadingVideo(false)
+                        updateCurrentStream()
+                        startPlaying()
+                    }
+                }
+
+                self.client.loadFile(stream.videoAsset.url, time: time) { [weak self] _ in
+                    self?.setIsLoadingVideo(true)
+                    self?.pause()
+                }
+            }
+        }
+
+        if preservingTime {
+            if model.preservedTime.isNil {
+                model.saveTime {
+                    replaceItem(self.model.preservedTime)
+                }
+            } else {
+                replaceItem(self.model.preservedTime)
+            }
+        } else {
+            replaceItem(nil)
+        }
+    }
+
+    func play() {
+        isPlaying = true
+        startClientUpdates()
+
+        client?.play()
+    }
+
+    func pause() {
+        isPlaying = false
+        stopClientUpdates()
+
+        client?.pause()
+    }
+
+    func togglePlay() {
+        isPlaying ? pause() : play()
+    }
+
+    func stop() {
+        client?.stop()
+    }
+
+    func seek(to time: CMTime, completionHandler: ((Bool) -> Void)?) {
+        client.seek(to: time) { [weak self] _ in
+            self?.getClientUpdates()
+            self?.updateControls()
+            completionHandler?(true)
+        }
+    }
+
+    func seek(relative time: CMTime, completionHandler: ((Bool) -> Void)? = nil) {
+        client.seek(relative: time) { [weak self] _ in
+            self?.getClientUpdates()
+            self?.updateControls()
+            completionHandler?(true)
+        }
+    }
+
+    func setRate(_: Float) {
+        // TODO: Implement rate change
+    }
+
+    func closeItem() {}
+
+    func enterFullScreen() {}
+
+    func exitFullScreen() {}
+
+    func closePiP(wasPlaying _: Bool) {}
+
+    func updateControls() {
+        DispatchQueue.main.async { [weak self] in
+            self?.logger.info("updating controls")
+            self?.controls.currentTime = self?.currentTime ?? .zero
+            self?.controls.duration = self?.playerItemDuration ?? .zero
+        }
+    }
+
+    func startControlsUpdates() {
+        self.logger.info("starting controls updates")
+        controlsUpdates = true
+    }
+
+    func stopControlsUpdates() {
+        self.logger.info("stopping controls updates")
+        controlsUpdates = false
+    }
+
+    func startClientUpdates() {
+        clientTimer.resume()
+    }
+
+    private func getClientUpdates() {
+        self.logger.info("getting client updates")
+
+        currentTime = client?.currentTime
+        playerItemDuration = client?.duration
+
+        if controlsUpdates {
+            updateControls()
+        }
+
+        if let currentTime = currentTime {
+            model.handleSegments(at: currentTime)
+        }
+
+        self.timeObserverThrottle.execute {
+            self.model.updateWatch()
+        }
+    }
+
+    private func stopClientUpdates() {
+        clientTimer.suspend()
+    }
+
+    private func updateControlsIsPlaying() {
+        DispatchQueue.main.async { [weak self] in
+            self?.controls.isPlaying = self?.isPlaying ?? false
+        }
+    }
+
+    private func setIsLoadingVideo(_ value: Bool) {
+        isLoadingVideo = value
+        DispatchQueue.main.async { [weak self] in
+            self?.controls.isLoadingVideo = value
+        }
+    }
+
+    func handle(_ event: UnsafePointer<mpv_event>!) {
+        logger.info("\(String(cString: mpv_event_name(event.pointee.event_id)))")
+
+        switch event.pointee.event_id {
+        case MPV_EVENT_SHUTDOWN:
+            mpv_destroy(client.mpv)
+            client.mpv = nil
+
+        case MPV_EVENT_LOG_MESSAGE:
+            let logmsg = UnsafeMutablePointer<mpv_event_log_message>(OpaquePointer(event.pointee.data))
+            logger.info(.init(stringLiteral: "log: \(String(cString: (logmsg!.pointee.prefix)!)), "
+                    + "\(String(cString: (logmsg!.pointee.level)!)), "
+                    + "\(String(cString: (logmsg!.pointee.text)!))"))
+
+        case MPV_EVENT_FILE_LOADED:
+            onFileLoaded?()
+            onFileLoaded = nil
+
+        case MPV_EVENT_END_FILE:
+            break
+            // DispatchQueue.main.async { [weak self] in
+            // TODO: handle EOF
+            // self?.handleEndOfFile(event)
+            // }
+
+        default:
+            logger.info(.init(stringLiteral: "event: \(String(cString: mpv_event_name(event.pointee.event_id)))"))
+        }
+    }
+
+    func handleEndOfFile(_: UnsafePointer<mpv_event>!) {
+        guard !isLoadingVideo else {
+            return
+        }
+
+        model.prepareCurrentItemForHistory(finished: true)
+
+        if model.queue.isEmpty {
+            #if !os(macOS)
+                try? AVAudioSession.sharedInstance().setActive(false)
+            #endif
+            model.resetQueue()
+
+            model.hide()
+        } else {
+            model.advanceToNextItem()
+        }
+    }
+
+    func setNeedsDrawing(_ needsDrawing: Bool) {
+        client?.setNeedsDrawing(needsDrawing)
+    }
+}