/*
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/

#import <React/RCTFPSGraph.h>

#import <React/RCTAssert.h>

#if RCT_DEV

@interface RCTFPSGraph ()

@property (nonatomic, strong, readonly) CAShapeLayer *graph;
@property (nonatomic, strong, readonly) UILabel *label;

@end

@implementation RCTFPSGraph {
CAShapeLayer *_graph;
UILabel *_label;

CGFloat *_frames;
UIColor *_color;

NSTimeInterval _prevTime;
NSUInteger _frameCount;
NSUInteger _FPS;
NSUInteger _maxFPS;
NSUInteger _minFPS;
NSUInteger _length;
NSUInteger _height;
}

- (instancetype)initWithFrame:(CGRect)frame color:(UIColor *)color
{
if ((self = [super initWithFrame:frame])) {
_frameCount = -1;
_prevTime = -1;
_maxFPS = 0;
_minFPS = 60;
_length = (NSUInteger)floor(frame.size.width);
_height = (NSUInteger)floor(frame.size.height);
_frames = calloc(sizeof(CGFloat), _length);
_color = color;

[self.layer addSublayer:self.graph];
[self addSubview:self.label];
}
return self;
}

- (void)dealloc
{
free(_frames);
}

RCT_NOT_IMPLEMENTED(-(instancetype)initWithFrame : (CGRect)frame)
RCT_NOT_IMPLEMENTED(-(instancetype)initWithCoder : (NSCoder *)aDecoder)

- (CAShapeLayer *)graph
{
if (!_graph) {
_graph = [CAShapeLayer new];
_graph.frame = self.bounds;
_graph.backgroundColor = [_color colorWithAlphaComponent:0.2].CGColor;
_graph.fillColor = _color.CGColor;
}

return _graph;
}

- (UILabel *)label
{
if (!_label) {
_label = [[UILabel alloc] initWithFrame:self.bounds];
_label.font = [UIFont boldSystemFontOfSize:13];
_label.textAlignment = NSTextAlignmentCenter;
}

return _label;
}

- (void)onTick:(NSTimeInterval)timestamp
{
_frameCount++;
if (_prevTime == -1) {
_prevTime = timestamp;
} else if (timestamp - _prevTime >= 1) {
_FPS = round(_frameCount / (timestamp - _prevTime));
_minFPS = MIN(_minFPS, _FPS);
_maxFPS = MAX(_maxFPS, _FPS);

dispatch_async(dispatch_get_main_queue(), ^{
self->_label.text = [NSString stringWithFormat:@"%lu", (unsigned long)self->_FPS];
});

CGFloat scale = 60.0 / _height;
for (NSUInteger i = 0; i < _length - 1; i++) {
_frames[i] = _frames[i + 1];
}
_frames[_length - 1] = _FPS / scale;

CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL, 0, _height);
for (NSUInteger i = 0; i < _length; i++) {
CGPathAddLineToPoint(path, NULL, i, _height - _frames[i]);
}
CGPathAddLineToPoint(path, NULL, _length - 1, _height);

_graph.path = path;
CGPathRelease(path);

_prevTime = timestamp;
_frameCount = 0;
}
}

@end

#endif