/*
 * This file is part of mpv.
 *
 * mpv is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * mpv is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with mpv.  If not, see <http://www.gnu.org/licenses/>.
 */

import Cocoa
import IOKit.pwr_mgt

class CocoaCB: NSObject {

    var mpv: MPVHelper!
    var window: Window!
    var view: EventsView!
    var layer: VideoLayer!
    var link: CVDisplayLink?

    var cursorHidden: Bool = false
    var cursorVisibilityWanted: Bool = true
    var isShuttingDown: Bool = false

    enum State {
        case uninit
        case needsInit
        case `init`
    }
    var backendState: State = .uninit

    let eventsLock = NSLock()
    var events: Int = 0

    var lightSensor: io_connect_t = 0
    var lastLmu: UInt64 = 0
    var lightSensorIOPort: IONotificationPortRef?
    var displaySleepAssertion: IOPMAssertionID = IOPMAssertionID(0)

    let queue: DispatchQueue = DispatchQueue(label: "io.mpv.queue")

    override init() {
        super.init()
        window = Window(cocoaCB: self)

        view = EventsView(frame: window.contentView!.bounds, cocoaCB: self)
        window.contentView!.addSubview(view)

        layer = VideoLayer(cocoaCB: self)
        view.layer = layer
        view.wantsLayer = true
        view.layerContentsPlacement = .scaleProportionallyToFit
    }

    func setMpvHandle(_ ctx: OpaquePointer) {
        mpv = MPVHelper(ctx)
        layer.setUpRender()
    }

    func preinit() {
        if backendState == .uninit {
            backendState = .needsInit
            DispatchQueue.main.async {
                self.updateICCProfile()
            }
            startDisplayLink()
        }
    }

    func uninit() {
        layer.setVideo(false)
        window.orderOut(nil)
    }

    func reconfig() {
        if backendState == .needsInit {
            initBackend()
        } else {
            layer.setVideo(true)
            updateWindowSize()
            layer.update()
        }
    }

    func initBackend() {
        NSApp.setActivationPolicy(.regular)

        let targetScreen = getTargetScreen(forFullscreen: false) ?? NSScreen.main()
        let wr = getWindowGeometry(forScreen: targetScreen!, videoOut: mpv.mpctx!.pointee.video_out)
        let win = Window(contentRect: wr, styleMask: window.styleMask,
                              screen: targetScreen, cocoaCB: self)
        win.title = window.title
        win.setOnTop(mpv.getBoolProperty("ontop"))
        win.keepAspect = mpv.getBoolProperty("keepaspect-window")
        window.close()
        window = win
        window.contentView!.addSubview(view)
        view.frame = window.contentView!.frame
        window.initTitleBar()

        setAppIcon()
        window.isRestorable = false
        window.makeMain()
        window.makeKeyAndOrderFront(nil)
        NSApp.activate(ignoringOtherApps: true)
        layer.setVideo(true)

        if mpv.getBoolProperty("fullscreen") {
            DispatchQueue.main.async {
                self.window.toggleFullScreen(nil)
            }
        } else {
            window.isMovableByWindowBackground = true
        }

        initLightSensor()
        addDisplayReconfigureObserver()
        backendState = .init
    }

    func updateWindowSize() {
        let targetScreen = getTargetScreen(forFullscreen: false) ?? NSScreen.main()
        let wr = getWindowGeometry(forScreen: targetScreen!, videoOut: mpv.mpctx!.pointee.video_out)
        if !window.isVisible {
            window.makeKeyAndOrderFront(nil)
        }
        layer.atomicDrawingStart()
        window.updateSize(wr.size)
    }

    func setAppIcon() {
        if let app = NSApp as? Application {
            NSApp.applicationIconImage = app.getMPVIcon()
        }
    }

    let linkCallback: CVDisplayLinkOutputCallback = {
                    (displayLink: CVDisplayLink,
                           inNow: UnsafePointer<CVTimeStamp>,
                    inOutputTime: UnsafePointer<CVTimeStamp>,
                         flagsIn: CVOptionFlags,
                        flagsOut: UnsafeMutablePointer<CVOptionFlags>,
              displayLinkContext: UnsafeMutableRawPointer?) -> CVReturn in
        let ccb: CocoaCB = MPVHelper.bridge(ptr: displayLinkContext!)
        ccb.mpv.reportRenderFlip()
        return kCVReturnSuccess
    }

    func startDisplayLink() {
        let displayId = UInt32(window.screen!.deviceDescription["NSScreenNumber"] as! Int)
        CVDisplayLinkCreateWithActiveCGDisplays(&link)
        CVDisplayLinkSetCurrentCGDisplay(link!, displayId)
        if #available(macOS 10.12, *) {
            CVDisplayLinkSetOutputHandler(link!) { link, now, out, inFlags, outFlags -> CVReturn in
                self.mpv.reportRenderFlip()
                return kCVReturnSuccess
            }
        } else {
            CVDisplayLinkSetOutputCallback(link!, linkCallback, MPVHelper.bridge(obj: self))
        }
        CVDisplayLinkStart(link!)
    }

    func stopDisplaylink() {
        if link != nil && CVDisplayLinkIsRunning(link!) {
            CVDisplayLinkStop(link!)
        }
    }

    func updateDisplaylink() {
        let displayId = UInt32(window.screen!.deviceDescription["NSScreenNumber"] as! Int)
        CVDisplayLinkSetCurrentCGDisplay(link!, displayId)

        queue.asyncAfter(deadline: DispatchTime.now() + 0.1) {
            self.flagEvents(VO_EVENT_WIN_STATE)
        }
    }

    func currentFps() -> Double {
        var actualFps = CVDisplayLinkGetActualOutputVideoRefreshPeriod(link!)
        let nominalData = CVDisplayLinkGetNominalOutputVideoRefreshPeriod(link!)

        if (nominalData.flags & Int32(CVTimeFlags.isIndefinite.rawValue)) < 1 {
            let nominalFps = Double(nominalData.timeScale) / Double(nominalData.timeValue)

            if actualFps > 0 {
                actualFps = 1/actualFps
            }

            if fabs(actualFps - nominalFps) > 0.1 {
                mpv.sendVerbose("Falling back to nominal display refresh rate: \(nominalFps)")
                return nominalFps
            } else {
                return actualFps
            }
        }
        mpv.sendWarning("Falling back to standard display refresh rate: 60Hz")
        return 60.0
    }

    func enableDisplaySleep() {
        IOPMAssertionRelease(displaySleepAssertion)
        displaySleepAssertion = IOPMAssertionID(0)
    }

    func disableDisplaySleep() {
        if displaySleepAssertion != IOPMAssertionID(0) { return }
        IOPMAssertionCreateWithName(
            kIOPMAssertionTypePreventUserIdleDisplaySleep as CFString,
            IOPMAssertionLevel(kIOPMAssertionLevelOn),
            "io.mpv.video_playing_back" as CFString,
            &displaySleepAssertion)
    }

    func updateCusorVisibility() {
        setCursorVisiblility(cursorVisibilityWanted)
    }

    func setCursorVisiblility(_ visible: Bool) {
        let visibility = visible ? true : !view.canHideCursor()

        if visibility && cursorHidden {
            NSCursor.unhide()
            cursorHidden = false;
        } else if !visibility && !cursorHidden {
            NSCursor.hide()
            cursorHidden = true
        }
    }

    func updateICCProfile() {
        mpv.setRenderICCProfile(window.screen!.colorSpace!)
        layer.colorspace = window.screen!.colorSpace!.cgColorSpace!
    }

    func lmuToLux(_ v: UInt64) -> Int {
        // the polinomial approximation for apple lmu value -> lux was empirically
        // derived by firefox developers (Apple provides no documentation).
        // https://bugzilla.mozilla.org/show_bug.cgi?id=793728
        let power_c4 = 1 / pow(10, 27)
        let power_c3 = 1 / pow(10, 19)
        let power_c2 = 1 / pow(10, 12)
        let power_c1 = 1 / pow(10, 5)

        let term4 = -3.0 * power_c4 * pow(Decimal(v), 4)
        let term3 = 2.6 * power_c3 * pow(Decimal(v), 3)
        let term2 = -3.4 * power_c2 * pow(Decimal(v), 2)
        let term1 = 3.9 * power_c1 * Decimal(v)

        let lux = Int(ceil( Double((term4 + term3 + term2 + term1 - 0.19) as NSNumber)))
        return Int(lux > 0 ? lux : 0)
    }

    var lightSensorCallback: IOServiceInterestCallback = { (ctx, service, messageType, messageArgument) -> Void in
        let ccb: CocoaCB = MPVHelper.bridge(ptr: ctx!)

        var outputs: UInt32 = 2
        var values: [UInt64] = [0, 0]

        var kr = IOConnectCallMethod(ccb.lightSensor, 0, nil, 0, nil, 0, &values, &outputs, nil, nil)
        if kr == KERN_SUCCESS {
            var mean = (values[0] + values[1]) / 2
            if ccb.lastLmu != mean {
                ccb.lastLmu = mean
                ccb.mpv.setRenderLux(ccb.lmuToLux(ccb.lastLmu))
            }
        }
    }

    func initLightSensor() {
        let srv = IOServiceGetMatchingService(kIOMasterPortDefault, IOServiceMatching("AppleLMUController"))
        if srv == IO_OBJECT_NULL {
            mpv.sendVerbose("Can't find an ambient light sensor")
            return
        }

        lightSensorIOPort = IONotificationPortCreate(kIOMasterPortDefault)
        IONotificationPortSetDispatchQueue(lightSensorIOPort, queue)
        var n = io_object_t()
        IOServiceAddInterestNotification(lightSensorIOPort, srv, kIOGeneralInterest, lightSensorCallback, MPVHelper.bridge(obj: self), &n)
        let kr = IOServiceOpen(srv, mach_task_self_, 0, &lightSensor)
        IOObjectRelease(srv)

        if kr != KERN_SUCCESS {
            mpv.sendVerbose("Can't start ambient light sensor connection")
            return
        }
        lightSensorCallback(MPVHelper.bridge(obj: self), 0, 0, nil)
    }

    func uninitLightSensor() {
        if lightSensorIOPort != nil {
            IONotificationPortDestroy(lightSensorIOPort)
            IOObjectRelease(lightSensor)
        }
    }

    var reconfigureCallback: CGDisplayReconfigurationCallBack = { (display, flags, userInfo) in
        if flags.contains(.setModeFlag) {
            let ccb: CocoaCB = MPVHelper.bridge(ptr: userInfo!)
            let displayID = (ccb.window.screen!.deviceDescription["NSScreenNumber"] as! NSNumber).intValue
            if UInt32(displayID) == display {
                ccb.mpv.sendVerbose("Detected display mode change, updating screen refresh rate\n");
                ccb.flagEvents(VO_EVENT_WIN_STATE)
            }
        }
    }

    func addDisplayReconfigureObserver() {
        CGDisplayRegisterReconfigurationCallback(reconfigureCallback, MPVHelper.bridge(obj: self))
    }

    func removeDisplayReconfigureObserver() {
        CGDisplayRemoveReconfigurationCallback(reconfigureCallback, MPVHelper.bridge(obj: self))
    }

    func getTargetScreen(forFullscreen fs: Bool) -> NSScreen? {
        let screenID = fs ? mpv.getStringProperty("fs-screen") ?? "current":
                            mpv.getStringProperty("screen") ?? "current"

        switch screenID {
        case "current", "default", "all":
            return getScreenBy(id: -1)
        default:
            return getScreenBy(id: Int(screenID)!)
        }
    }

    func getScreenBy(id screenID: Int) -> NSScreen? {
        let screens = NSScreen.screens()
        if screenID >= screens!.count {
            mpv.sendInfo("Screen ID \(screenID) does not exist, falling back to current device")
            return nil
        } else if screenID < 0 {
            return nil
        }
        return screens![screenID]
    }

    func getWindowGeometry(forScreen targetScreen: NSScreen,
                           videoOut vo: UnsafeMutablePointer<vo>) -> NSRect {
        let r = targetScreen.convertRectToBacking(targetScreen.frame)
        var screenRC: mp_rect = mp_rect(x0: Int32(0),
                                        y0: Int32(0),
                                        x1: Int32(r.size.width),
                                        y1: Int32(r.size.height))

        var geo: vo_win_geometry = vo_win_geometry()
        vo_calc_window_geometry2(vo, &screenRC, Double(targetScreen.backingScaleFactor), &geo)

        // flip y coordinates
        geo.win.y1 = Int32(r.size.height) - geo.win.y1
        geo.win.y0 = Int32(r.size.height) - geo.win.y0

        let wr = NSMakeRect(CGFloat(geo.win.x0), CGFloat(geo.win.y1),
                            CGFloat(geo.win.x1 - geo.win.x0),
                            CGFloat(geo.win.y0 - geo.win.y1))
        return targetScreen.convertRectFromBacking(wr)
    }

    func flagEvents(_ ev: Int) {
        eventsLock.lock()
        events |= ev
        eventsLock.unlock()
    }

    func checkEvents() -> Int {
        eventsLock.lock()
        let ev = events
        events = 0
        eventsLock.unlock()
        return ev
    }

    var controlCallback: mp_render_cb_control_fn = { ( ctx, events, request, data ) -> Int32 in
        let ccb: CocoaCB = MPVHelper.bridge(ptr: ctx!)

        switch mp_voctrl(request) {
        case VOCTRL_CHECK_EVENTS:
            events!.pointee = Int32(ccb.checkEvents())
            return VO_TRUE
        case VOCTRL_FULLSCREEN:
            DispatchQueue.main.async {
                ccb.window.toggleFullScreen(nil)
            }
            return VO_TRUE
        case VOCTRL_GET_FULLSCREEN:
            let fsData = data!.assumingMemoryBound(to: Int32.self)
            fsData.pointee = ccb.window.isInFullscreen ? 1 : 0
            return VO_TRUE
        case VOCTRL_GET_DISPLAY_FPS:
            let fps = data!.assumingMemoryBound(to: CDouble.self)
            fps.pointee = ccb.currentFps()
            return VO_TRUE
        case VOCTRL_RESTORE_SCREENSAVER:
            ccb.enableDisplaySleep()
            return VO_TRUE
        case VOCTRL_KILL_SCREENSAVER:
            ccb.disableDisplaySleep()
            return VO_TRUE
        case VOCTRL_SET_CURSOR_VISIBILITY:
            ccb.cursorVisibilityWanted = data!.assumingMemoryBound(to: CBool.self).pointee
            DispatchQueue.main.async {
                ccb.setCursorVisiblility(ccb.cursorVisibilityWanted)
            }
            return VO_TRUE
        case VOCTRL_SET_UNFS_WINDOW_SIZE:
            let sizeData = data!.assumingMemoryBound(to: Int32.self)
            let size = UnsafeBufferPointer(start: sizeData, count: 2)
            var rect = NSMakeRect(0, 0, CGFloat(size[0]), CGFloat(size[1]))
            DispatchQueue.main.async {
                if !ccb.mpv.getBoolProperty("hidpi-window-scale") {
                    rect = ccb.window.currentScreen!.convertRectFromBacking(rect)
                }
                ccb.window.updateSize(rect.size)
            }
            return VO_TRUE
        case VOCTRL_GET_WIN_STATE:
            let minimized = data!.assumingMemoryBound(to: Int32.self)
            minimized.pointee = ccb.window.isMiniaturized ? VO_WIN_STATE_MINIMIZED : Int32(0)
            return VO_TRUE
        case VOCTRL_UPDATE_WINDOW_TITLE:
            let titleData = data!.assumingMemoryBound(to: Int8.self)
            let title = String(cString: titleData)
            DispatchQueue.main.async {
                ccb.window.title = String(cString: titleData)
            }
            return VO_TRUE
        case VOCTRL_PREINIT:
            ccb.preinit()
            return VO_TRUE
        case VOCTRL_UNINIT:
            DispatchQueue.main.async {
                ccb.uninit()
            }
            return VO_TRUE
        case VOCTRL_RECONFIG:
            DispatchQueue.main.async {
                ccb.reconfig()
            }
            return VO_TRUE
        default:
            return VO_NOTIMPL
        }
    }

    func shutdown(_ destroy: Bool = false) {
        setCursorVisiblility(true)
        layer.setVideo(false)
        stopDisplaylink()
        uninitLightSensor()
        removeDisplayReconfigureObserver()
        mpv.deinitRender()
        mpv.deinitMPV(destroy)
    }

    func checkShutdown() {
        if isShuttingDown {
            shutdown(true)
        }
    }

    func processEvent(_ event: UnsafePointer<mpv_event>) {
        switch event.pointee.event_id {
        case MPV_EVENT_SHUTDOWN:
            if window.isAnimating {
                isShuttingDown = true
                return
            }
            shutdown()
        case MPV_EVENT_PROPERTY_CHANGE:
            if backendState == .init {
                handlePropertyChange(event)
            }
        default:
            break
        }
    }

    func handlePropertyChange(_ event: UnsafePointer<mpv_event>) {
        let pData = OpaquePointer(event.pointee.data)
        guard let property = UnsafePointer<mpv_event_property>(pData)?.pointee else {
            return
        }

        switch String(cString: property.name) {
        case "border":
            if let data = MPVHelper.mpvFlagToBool(property.data) {
                window.border = data
            }
        case "ontop":
            if let data = MPVHelper.mpvFlagToBool(property.data) {
                window.setOnTop(data)
            }
        case "keepaspect-window":
            if let data = MPVHelper.mpvFlagToBool(property.data) {
                window.keepAspect = data
            }
        case "macos-title-bar-style":
            if let data = MPVHelper.mpvStringArrayToString(property.data) {
                window.setTitleBarStyle(data)
            }
        default:
            break
        }
    }
}