#include "UnityAppController+Rendering.h"
#include "UnityAppController+ViewHandling.h"

#include "Unity/InternalProfiler.h"
#include "Unity/UnityMetalSupport.h"
#include "Unity/DisplayManager.h"

#include "UI/UnityView.h"

#include <dlfcn.h>

// _glesContextCreated was renamed to _renderingInited
extern bool _renderingInited;
extern bool _unityAppReady;
extern bool _skipPresent;
extern bool _didResignActive;

static int _renderingAPI = 0;
static int SelectRenderingAPIImpl();

static bool _enableRunLoopAcceptInput = false;

cp_layer_renderer_t _LayerRenderer = nil;
static cp_layer_renderer_state _LayerRendererState = cp_layer_renderer_state_running;
static bool _ShouldDispatchRepaint = false;

@implementation UnityAppController (Rendering)

- (void)createDisplayLink
{
    _displayLink = [CADisplayLink displayLinkWithTarget: self selector: @selector(repaintDisplayLink)];
    [self callbackFramerateChange: -1];
    [_displayLink addToRunLoop: [NSRunLoop currentRunLoop] forMode: NSRunLoopCommonModes];
}

- (void)destroyDisplayLink
{
    [_displayLink invalidate];
    _displayLink = nil;
}

- (void)repaintDisplayLink
{
    if (_LayerRenderer == nil)
    {
        if (!_didResignActive) {
            UnityDisplayLinkCallback(_displayLink.timestamp);
            [self repaint];
        }
    }
    else
    {
        if (_LayerRendererState == cp_layer_renderer_state_running)
        {
            if (UnityIsPaused())
            {
                UnityWillResume();
                UnityPause(0);
            }
            
            UnityDisplayLinkCallback(0.0);
            [self repaint];
        }
        else 
        {
            if (!UnityIsPaused())
                UnityPause(1);

            _LayerRendererState = cp_layer_renderer_get_state(_LayerRenderer);
        }

        if (_ShouldDispatchRepaint)
            dispatch_async(dispatch_get_main_queue(), ^{ [self repaintDisplayLink]; });
    }
}

- (void)repaint
{
#if UNITY_SUPPORT_ROTATION
    [self checkOrientationRequest];
#endif
    [_unityView recreateRenderingSurfaceIfNeeded];
    [_unityView processKeyboard];
    UnityDeliverUIEvents();

    if (!UnityIsPaused())
        UnityRepaint();
}

- (void)callbackGfxInited
{
    InitRendering();
    _renderingInited = true;

    [self shouldAttachRenderDelegate];
    [_unityView recreateRenderingSurface];
    [_renderDelegate mainDisplayInited: _mainDisplay.surface];

    _mainDisplay.surface->allowScreenshot = 1;
}

- (void)callbackPresent:(const UnityFrameStats*)frameStats
{
    if (_skipPresent)
        return;

    // metal needs special processing, because in case of airplay we need extra command buffers to present non-main screen drawables
    if (UnitySelectedRenderingAPI() == apiMetal)
    {
        [[DisplayManager Instance].mainDisplay present];
#if !PLATFORM_VISIONOS
        [[DisplayManager Instance] enumerateNonMainDisplaysWithBlock:^(DisplayConnection* conn) {
            PreparePresentNonMainScreenMTL((UnityDisplaySurfaceMTL*)conn.surface);
        }];
#endif
    }
    else
    {
        [[DisplayManager Instance] present];
    }

    Profiler_FramePresent(frameStats);
}

- (void)callbackFramerateChange:(int)targetFPS
{
#if !PLATFORM_VISIONOS
    int maxFPS = (int)[UIScreen mainScreen].maximumFramesPerSecond;
#else
    // hardcode for visionOS?
    int maxFPS = 90;
#endif
    if (targetFPS <= 0)
        targetFPS = UnityGetTargetFPS();
    if (targetFPS > maxFPS)
    {
        targetFPS = maxFPS;
        UnitySetTargetFPS(targetFPS);
        return;
    }

    _enableRunLoopAcceptInput = (targetFPS == maxFPS && UnityDeviceCPUCount() > 1);

    if (@available(iOS 15.0, tvOS 15.0, *))
        _displayLink.preferredFrameRateRange = CAFrameRateRangeMake(targetFPS, targetFPS, targetFPS);
    else
        _displayLink.preferredFramesPerSecond = targetFPS;
}

- (void)selectRenderingAPI
{
    NSAssert(_renderingAPI == 0, @"[UnityAppController selectRenderingApi] called twice");
    _renderingAPI = SelectRenderingAPIImpl();
}

- (UnityRenderingAPI)renderingAPI
{
    NSAssert(_renderingAPI != 0, @"[UnityAppController renderingAPI] called before [UnityAppController selectRenderingApi]");
    return (UnityRenderingAPI)_renderingAPI;
}

@end

@interface UnityVisionOSCompositorBridge : NSObject

+ (void)setLayerRenderer:(cp_layer_renderer_t)layerRenderer;
+ (void)setLayerRendererState:(NSNumber*)layerRendererState;

@end

@implementation UnityVisionOSCompositorBridge

+ (void)setLayerRenderer:(cp_layer_renderer_t)layerRenderer
{
    _LayerRenderer = layerRenderer;
    if (layerRenderer == nil)
    {
        _ShouldDispatchRepaint = false;
        [_UnityAppController createDisplayLink];
    }
    else
    {
        _ShouldDispatchRepaint = true;
        [_UnityAppController destroyDisplayLink];
        
        // Manually call repaintDisplayLink to kick off dispatched repaint loop
        [_UnityAppController repaintDisplayLink];
    }
}

+ (void)setLayerRendererState:(NSNumber*) layerRendererStateObject
{
    _LayerRendererState = (cp_layer_renderer_state)layerRendererStateObject.intValue;
}

@end

extern "C" void UnityGfxInitedCallback()
{
    [GetAppController() callbackGfxInited];
}

extern "C" void UnityPresentContextCallback(struct UnityFrameStats const* unityFrameStats)
{
    [GetAppController() callbackPresent: unityFrameStats];
}

extern "C" void UnityFramerateChangeCallback(int targetFPS)
{
    [GetAppController() callbackFramerateChange: targetFPS];
}

static NSBundle*        _MetalBundle    = nil;
static id<MTLDevice>    _MetalDevice    = nil;

static bool IsMetalSupported(int /*api*/)
{
    _MetalBundle = [NSBundle bundleWithPath: @"/System/Library/Frameworks/Metal.framework"];
    if (_MetalBundle)
    {
        [_MetalBundle load];
        _MetalDevice = ((MTLCreateSystemDefaultDeviceFunc)::dlsym(dlopen(0, RTLD_LOCAL | RTLD_LAZY), "MTLCreateSystemDefaultDevice"))();
        if (_MetalDevice)
            return true;
    }

    [_MetalBundle unload];
    return false;
}

static int SelectRenderingAPIImpl()
{
    const int api = UnityGetRenderingAPI();
    if (api == apiMetal && IsMetalSupported(0))
        return api;

#if TARGET_IPHONE_SIMULATOR || TARGET_TVOS_SIMULATOR
    printf_console("On Simulator, Metal is supported only from iOS 13, and it requires at least macOS 10.15 and Xcode 11. Setting no graphics device.\n");
#endif
    return apiNoGraphics;
}

extern "C" NSBundle*            UnityGetMetalBundle()
{
    return _MetalBundle;
}

extern "C" MTLDeviceRef         UnityGetMetalDevice()       { return _MetalDevice; }
extern "C" MTLCommandQueueRef   UnityGetMetalCommandQueue() { return ((UnityDisplaySurfaceMTL*)GetMainDisplaySurface())->commandQueue; }
extern "C" int                  UnitySelectedRenderingAPI() { return _renderingAPI; }

// deprecated and no longer used by unity itself (will soon be removed)
extern "C" MTLCommandQueueRef   UnityGetMetalDrawableCommandQueue() { return UnityGetMetalCommandQueue(); }


extern "C" UnityRenderBufferHandle  UnityBackbufferColor()      { return GetMainDisplaySurface()->unityColorBuffer; }
extern "C" UnityRenderBufferHandle  UnityBackbufferDepth()      { return GetMainDisplaySurface()->unityDepthBuffer; }

extern "C" void                 DisplayManagerEndFrameRendering() { [[DisplayManager Instance] endFrameRendering]; }

extern "C" void                 UnityPrepareScreenshot()    { UnitySetRenderTarget(GetMainDisplaySurface()->unityColorBuffer, GetMainDisplaySurface()->unityDepthBuffer); }

extern "C" void UnityRepaint()
{
    @autoreleasepool
    {
        Profiler_FrameStart();
        if (UnityIsBatchmode())
            UnityBatchPlayerLoop();
        else
            UnityPlayerLoop();
        Profiler_FrameEnd();
    }
}