//
//  VideoDecoderRenderer.m
//  Moonlight
//
//  Created by Cameron Gutman on 10/18/14.
//  Copyright (c) 2014 Moonlight Stream. All rights reserved.
//

#import "VideoDecoderRenderer.h"
#import "StreamView.h"

#include "Limelight.h"

@implementation VideoDecoderRenderer {
    StreamView* _view;
    id<ConnectionCallbacks> _callbacks;
    float _streamAspectRatio;
    
    AVSampleBufferDisplayLayer* displayLayer;
    int videoFormat, videoWidth, videoHeight;
    int frameRate;
    
    NSMutableArray *parameterSetBuffers;
    NSData *masteringDisplayColorVolume;
    NSData *contentLightLevelInfo;
    CMVideoFormatDescriptionRef formatDesc;
    
    CADisplayLink* _displayLink;
    BOOL framePacing;
}

- (void)reinitializeDisplayLayer
{
    CALayer *oldLayer = displayLayer;
    
    displayLayer = [[AVSampleBufferDisplayLayer alloc] init];
    displayLayer.backgroundColor = [UIColor blackColor].CGColor;
    
    // Ensure the AVSampleBufferDisplayLayer is sized to preserve the aspect ratio
    // of the video stream. We used to use AVLayerVideoGravityResizeAspect, but that
    // respects the PAR encoded in the SPS which causes our computed video-relative
    // touch location to be wrong in StreamView if the aspect ratio of the host
    // desktop doesn't match the aspect ratio of the stream.
    CGSize videoSize;
    if (_view.bounds.size.width > _view.bounds.size.height * _streamAspectRatio) {
        videoSize = CGSizeMake(_view.bounds.size.height * _streamAspectRatio, _view.bounds.size.height);
    } else {
        videoSize = CGSizeMake(_view.bounds.size.width, _view.bounds.size.width / _streamAspectRatio);
    }
    displayLayer.position = CGPointMake(CGRectGetMidX(_view.bounds), CGRectGetMidY(_view.bounds));
    displayLayer.bounds = CGRectMake(0, 0, videoSize.width, videoSize.height);
    displayLayer.videoGravity = AVLayerVideoGravityResize;

    // Hide the layer until we get an IDR frame. This ensures we
    // can see the loading progress label as the stream is starting.
    displayLayer.hidden = YES;
    
    if (oldLayer != nil) {
        // Switch out the old display layer with the new one
        [_view.layer replaceSublayer:oldLayer with:displayLayer];
    }
    else {
        [_view.layer addSublayer:displayLayer];
    }
    
    if (formatDesc != nil) {
        CFRelease(formatDesc);
        formatDesc = nil;
    }
}

- (id)initWithView:(StreamView*)view callbacks:(id<ConnectionCallbacks>)callbacks streamAspectRatio:(float)aspectRatio useFramePacing:(BOOL)useFramePacing
{
    self = [super init];
    
    _view = view;
    _callbacks = callbacks;
    _streamAspectRatio = aspectRatio;
    framePacing = useFramePacing;
    
    parameterSetBuffers = [[NSMutableArray alloc] init];
    
    [self reinitializeDisplayLayer];
    
    return self;
}

- (void)setupWithVideoFormat:(int)videoFormat width:(int)videoWidth height:(int)videoHeight frameRate:(int)frameRate
{
    self->videoFormat = videoFormat;
    self->videoWidth = videoWidth;
    self->videoHeight = videoHeight;
    self->frameRate = frameRate;
}

- (void)start
{
    _displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(displayLinkCallback:)];
    if (@available(iOS 15.0, tvOS 15.0, *)) {
        _displayLink.preferredFrameRateRange = CAFrameRateRangeMake(self->frameRate, self->frameRate, self->frameRate);
    }
    else {
        _displayLink.preferredFramesPerSecond = self->frameRate;
    }
    [_displayLink addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];
}

// TODO: Refactor this
int DrSubmitDecodeUnit(PDECODE_UNIT decodeUnit);

- (void)displayLinkCallback:(CADisplayLink *)sender
{
    VIDEO_FRAME_HANDLE handle;
    PDECODE_UNIT du;
    
    while (LiPollNextVideoFrame(&handle, &du)) {
        LiCompleteVideoFrame(handle, DrSubmitDecodeUnit(du));
        
        if (framePacing) {
            // Calculate the actual display refresh rate
            double displayRefreshRate = 1 / (_displayLink.targetTimestamp - _displayLink.timestamp);
            
            // Only pace frames if the display refresh rate is >= 90% of our stream frame rate.
            // Battery saver, accessibility settings, or device thermals can cause the actual
            // refresh rate of the display to drop below the physical maximum.
            if (displayRefreshRate >= frameRate * 0.9f) {
                // Keep one pending frame to smooth out gaps due to
                // network jitter at the cost of 1 frame of latency
                if (LiGetPendingVideoFrames() == 1) {
                    break;
                }
            }
        }
    }
}

- (void)stop
{
    [_displayLink invalidate];
}

#define NALU_START_PREFIX_SIZE 3
#define NAL_LENGTH_PREFIX_SIZE 4

- (void)updateAnnexBBufferForRange:(CMBlockBufferRef)frameBuffer dataBlock:(CMBlockBufferRef)dataBuffer offset:(int)offset length:(int)nalLength
{
    OSStatus status;
    size_t oldOffset = CMBlockBufferGetDataLength(frameBuffer);
    
    // Append a 4 byte buffer to the frame block for the length prefix
    status = CMBlockBufferAppendMemoryBlock(frameBuffer, NULL,
                                            NAL_LENGTH_PREFIX_SIZE,
                                            kCFAllocatorDefault, NULL, 0,
                                            NAL_LENGTH_PREFIX_SIZE, 0);
    if (status != noErr) {
        Log(LOG_E, @"CMBlockBufferAppendMemoryBlock failed: %d", (int)status);
        return;
    }
    
    // Write the length prefix to the new buffer
    const int dataLength = nalLength - NALU_START_PREFIX_SIZE;
    const uint8_t lengthBytes[] = {(uint8_t)(dataLength >> 24), (uint8_t)(dataLength >> 16),
        (uint8_t)(dataLength >> 8), (uint8_t)dataLength};
    status = CMBlockBufferReplaceDataBytes(lengthBytes, frameBuffer,
                                           oldOffset, NAL_LENGTH_PREFIX_SIZE);
    if (status != noErr) {
        Log(LOG_E, @"CMBlockBufferReplaceDataBytes failed: %d", (int)status);
        return;
    }
    
    // Attach the data buffer to the frame buffer by reference
    status = CMBlockBufferAppendBufferReference(frameBuffer, dataBuffer, offset + NALU_START_PREFIX_SIZE, dataLength, 0);
    if (status != noErr) {
        Log(LOG_E, @"CMBlockBufferAppendBufferReference failed: %d", (int)status);
        return;
    }
}

// This function must free data for bufferType == BUFFER_TYPE_PICDATA
- (int)submitDecodeBuffer:(unsigned char *)data length:(int)length bufferType:(int)bufferType frameType:(int)frameType pts:(unsigned int)pts
{
    OSStatus status;
    
    // Construct a new format description object each time we receive an IDR frame
    if (frameType == FRAME_TYPE_IDR) {
        if (bufferType != BUFFER_TYPE_PICDATA) {
            if (bufferType == BUFFER_TYPE_VPS || bufferType == BUFFER_TYPE_SPS || bufferType == BUFFER_TYPE_PPS) {
                // Add new parameter set into the parameter set array
                int startLen = data[2] == 0x01 ? 3 : 4;
                [parameterSetBuffers addObject:[NSData dataWithBytes:&data[startLen] length:length - startLen]];
                
                // We must reconstruct the format description if we get new parameter sets
                formatDesc = NULL;
            }
            
            // Data is NOT to be freed here. It's a direct usage of the caller's buffer.
            
            // No frame data to submit for these NALUs
            return DR_OK;
        }
        else if (frameType == FRAME_TYPE_IDR && formatDesc == NULL) {
            // Create the new format description when we get the first picture data buffer of an IDR frame.
            // This is the only way we know that there is no more CSD for this frame.
            if (videoFormat & VIDEO_FORMAT_MASK_H264) {
                // Construct parameter set arrays for the format description
                size_t parameterSetCount = [parameterSetBuffers count];
                const uint8_t* parameterSetPointers[parameterSetCount];
                size_t parameterSetSizes[parameterSetCount];
                for (int i = 0; i < parameterSetCount; i++) {
                    NSData* parameterSet = parameterSetBuffers[i];
                    parameterSetPointers[i] = parameterSet.bytes;
                    parameterSetSizes[i] = parameterSet.length;
                }
                
                Log(LOG_I, @"Constructing new H264 format description");
                status = CMVideoFormatDescriptionCreateFromH264ParameterSets(kCFAllocatorDefault,
                                                                             parameterSetCount,
                                                                             parameterSetPointers,
                                                                             parameterSetSizes,
                                                                             NAL_LENGTH_PREFIX_SIZE,
                                                                             &formatDesc);
                if (status != noErr) {
                    Log(LOG_E, @"Failed to create H264 format description: %d", (int)status);
                    formatDesc = NULL;
                }
                
                // Free parameter set buffers after submission
                [parameterSetBuffers removeAllObjects];
            }
            else if (videoFormat & VIDEO_FORMAT_MASK_H265) {
                // Construct parameter set arrays for the format description
                size_t parameterSetCount = [parameterSetBuffers count];
                const uint8_t* parameterSetPointers[parameterSetCount];
                size_t parameterSetSizes[parameterSetCount];
                for (int i = 0; i < parameterSetCount; i++) {
                    NSData* parameterSet = parameterSetBuffers[i];
                    parameterSetPointers[i] = parameterSet.bytes;
                    parameterSetSizes[i] = parameterSet.length;
                }
                
                Log(LOG_I, @"Constructing new HEVC format description");
                
                NSMutableDictionary* videoFormatParams = [[NSMutableDictionary alloc] init];
                
                if (contentLightLevelInfo) {
                    [videoFormatParams setObject:contentLightLevelInfo forKey:(__bridge NSString*)kCMFormatDescriptionExtension_ContentLightLevelInfo];
                }
                
                if (masteringDisplayColorVolume) {
                    [videoFormatParams setObject:masteringDisplayColorVolume forKey:(__bridge NSString*)kCMFormatDescriptionExtension_MasteringDisplayColorVolume];
                }
                
                status = CMVideoFormatDescriptionCreateFromHEVCParameterSets(kCFAllocatorDefault,
                                                                             parameterSetCount,
                                                                             parameterSetPointers,
                                                                             parameterSetSizes,
                                                                             NAL_LENGTH_PREFIX_SIZE,
                                                                             (__bridge CFDictionaryRef)videoFormatParams,
                                                                             &formatDesc);
                
                if (status != noErr) {
                    Log(LOG_E, @"Failed to create HEVC format description: %d", (int)status);
                    formatDesc = NULL;
                }
                
                // Free parameter set buffers after submission
                [parameterSetBuffers removeAllObjects];
            }
#if defined(__IPHONE_16_0) || defined(__TVOS_16_0)
            else if (videoFormat & VIDEO_FORMAT_MASK_AV1) {
                // AV1 doesn't have a special format description function like H.264 and HEVC have, so we just use the generic one
                // TODO: Is this correct?
                status = CMVideoFormatDescriptionCreate(kCFAllocatorDefault, kCMVideoCodecType_AV1, videoWidth, videoHeight, nil, &formatDesc);
                if (status != noErr) {
                    Log(LOG_E, @"Failed to create AV1 format description: %d", (int)status);
                    formatDesc = NULL;
                }
            }
#endif
            else {
                // Unsupported codec!
                abort();
            }
        }
    }
    
    if (formatDesc == NULL) {
        // Can't decode if we haven't gotten our parameter sets yet
        free(data);
        return DR_NEED_IDR;
    }
    
    // Check for previous decoder errors before doing anything
    if (displayLayer.status == AVQueuedSampleBufferRenderingStatusFailed) {
        Log(LOG_E, @"Display layer rendering failed: %@", displayLayer.error);
        
        // Recreate the display layer. We are already on the main thread,
        // so this is safe to do right here.
        [self reinitializeDisplayLayer];
        
        // Request an IDR frame to initialize the new decoder
        free(data);
        return DR_NEED_IDR;
    }
    
    // Now we're decoding actual frame data here
    CMBlockBufferRef frameBlockBuffer;
    CMBlockBufferRef dataBlockBuffer;
    
    status = CMBlockBufferCreateWithMemoryBlock(NULL, data, length, kCFAllocatorDefault, NULL, 0, length, 0, &dataBlockBuffer);
    if (status != noErr) {
        Log(LOG_E, @"CMBlockBufferCreateWithMemoryBlock failed: %d", (int)status);
        free(data);
        return DR_NEED_IDR;
    }
    
    // From now on, CMBlockBuffer owns the data pointer and will free it when it's dereferenced
    
    status = CMBlockBufferCreateEmpty(NULL, 0, 0, &frameBlockBuffer);
    if (status != noErr) {
        Log(LOG_E, @"CMBlockBufferCreateEmpty failed: %d", (int)status);
        CFRelease(dataBlockBuffer);
        return DR_NEED_IDR;
    }
    
    // H.264 and HEVC formats require NAL prefix fixups from Annex B to length-delimited
    if (videoFormat & (VIDEO_FORMAT_MASK_H264 | VIDEO_FORMAT_MASK_H265)) {
        int lastOffset = -1;
        for (int i = 0; i < length - NALU_START_PREFIX_SIZE; i++) {
            // Search for a NALU
            if (data[i] == 0 && data[i+1] == 0 && data[i+2] == 1) {
                // It's the start of a new NALU
                if (lastOffset != -1) {
                    // We've seen a start before this so enqueue that NALU
                    [self updateAnnexBBufferForRange:frameBlockBuffer dataBlock:dataBlockBuffer offset:lastOffset length:i - lastOffset];
                }
                
                lastOffset = i;
            }
        }
        
        if (lastOffset != -1) {
            // Enqueue the remaining data
            [self updateAnnexBBufferForRange:frameBlockBuffer dataBlock:dataBlockBuffer offset:lastOffset length:length - lastOffset];
        }
    }
    else {
        // For formats that require no length-changing fixups, just append a reference to the raw data block
        status = CMBlockBufferAppendBufferReference(frameBlockBuffer, dataBlockBuffer, 0, length, 0);
        if (status != noErr) {
            Log(LOG_E, @"CMBlockBufferAppendBufferReference failed: %d", (int)status);
            return DR_NEED_IDR;
        }
    }
        
    CMSampleBufferRef sampleBuffer;
    
    CMSampleTimingInfo sampleTiming = {kCMTimeInvalid, CMTimeMake(pts, 1000), kCMTimeInvalid};
    
    status = CMSampleBufferCreateReady(kCFAllocatorDefault,
                                  frameBlockBuffer,
                                  formatDesc, 1, 1,
                                  &sampleTiming, 0, NULL,
                                  &sampleBuffer);
    if (status != noErr) {
        Log(LOG_E, @"CMSampleBufferCreate failed: %d", (int)status);
        CFRelease(dataBlockBuffer);
        CFRelease(frameBlockBuffer);
        return DR_NEED_IDR;
    }

    // Enqueue the next frame
    [self->displayLayer enqueueSampleBuffer:sampleBuffer];
    
    if (frameType == FRAME_TYPE_IDR) {
        // Ensure the layer is visible now
        self->displayLayer.hidden = NO;
        
        // Tell our parent VC to hide the progress indicator
        [self->_callbacks videoContentShown];
    }
    
    // Dereference the buffers
    CFRelease(dataBlockBuffer);
    CFRelease(frameBlockBuffer);
    CFRelease(sampleBuffer);
    
    return DR_OK;
}

- (void)setHdrMode:(BOOL)enabled {
    SS_HDR_METADATA hdrMetadata;
    
    BOOL hasMetadata = enabled && LiGetHdrMetadata(&hdrMetadata);
    BOOL metadataChanged = NO;
    
    if (hasMetadata && hdrMetadata.displayPrimaries[0].x != 0 && hdrMetadata.maxDisplayLuminance != 0) {
        // This data is all in big-endian
        struct {
          vector_ushort2 primaries[3];
          vector_ushort2 white_point;
          uint32_t luminance_max;
          uint32_t luminance_min;
        } __attribute__((packed, aligned(4))) mdcv;

        // mdcv is in GBR order while SS_HDR_METADATA is in RGB order
        mdcv.primaries[0].x = __builtin_bswap16(hdrMetadata.displayPrimaries[1].x);
        mdcv.primaries[0].y = __builtin_bswap16(hdrMetadata.displayPrimaries[1].y);
        mdcv.primaries[1].x = __builtin_bswap16(hdrMetadata.displayPrimaries[2].x);
        mdcv.primaries[1].y = __builtin_bswap16(hdrMetadata.displayPrimaries[2].y);
        mdcv.primaries[2].x = __builtin_bswap16(hdrMetadata.displayPrimaries[0].x);
        mdcv.primaries[2].y = __builtin_bswap16(hdrMetadata.displayPrimaries[0].y);

        mdcv.white_point.x = __builtin_bswap16(hdrMetadata.whitePoint.x);
        mdcv.white_point.y = __builtin_bswap16(hdrMetadata.whitePoint.y);

        // These luminance values are in 10000ths of a nit
        mdcv.luminance_max = __builtin_bswap32((uint32_t)hdrMetadata.maxDisplayLuminance * 10000);
        mdcv.luminance_min = __builtin_bswap32(hdrMetadata.minDisplayLuminance);

        NSData* newMdcv = [NSData dataWithBytes:&mdcv length:sizeof(mdcv)];
        if (masteringDisplayColorVolume == nil || ![newMdcv isEqualToData:masteringDisplayColorVolume]) {
            masteringDisplayColorVolume = newMdcv;
            metadataChanged = YES;
        }
    }
    else if (masteringDisplayColorVolume != nil) {
        masteringDisplayColorVolume = nil;
        metadataChanged = YES;
    }
    
    if (hasMetadata && hdrMetadata.maxContentLightLevel != 0 && hdrMetadata.maxFrameAverageLightLevel != 0) {
        // This data is all in big-endian
        struct {
            uint16_t max_content_light_level;
            uint16_t max_frame_average_light_level;
        } __attribute__((packed, aligned(2))) cll;

        cll.max_content_light_level = __builtin_bswap16(hdrMetadata.maxContentLightLevel);
        cll.max_frame_average_light_level = __builtin_bswap16(hdrMetadata.maxFrameAverageLightLevel);

        NSData* newCll = [NSData dataWithBytes:&cll length:sizeof(cll)];
        if (contentLightLevelInfo == nil || ![newCll isEqualToData:contentLightLevelInfo]) {
            contentLightLevelInfo = newCll;
            metadataChanged = YES;
        }
    }
    else if (contentLightLevelInfo != nil) {
        contentLightLevelInfo = nil;
        metadataChanged = YES;
    }
    
    // If the metadata changed, request an IDR frame to re-create the CMVideoFormatDescription
    if (metadataChanged) {
        LiRequestIdrFrame();
    }
}

@end